hush: make expand_vars_to_list() a bit more sane
[oweals/busybox.git] / shell / ash.c
index b285e3d33b3f96dd3f5975a6d53f00437454f492..051cc671fcef4a21d68a36ccea38c8251ce476fc 100644 (file)
 //config:      default y
 //config:      depends on ASH || SH_IS_ASH || BASH_IS_ASH
 //config:
+//config:config ASH_BASH_SOURCE_CURDIR
+//config:      bool "'source' and '.' builtins search current directory after $PATH"
+//config:      default n   # do not encourage non-standard behavior
+//config:      depends on ASH_BASH_COMPAT
+//config:      help
+//config:      This is not compliant with standards. Avoid if possible.
+//config:
+//config:config ASH_BASH_NOT_FOUND_HOOK
+//config:      bool "command_not_found_handle hook support"
+//config:      default y
+//config:      depends on ASH_BASH_COMPAT
+//config:      help
+//config:      Enable support for the 'command_not_found_handle' hook function,
+//config:      from GNU bash, which allows for alternative command not found
+//config:      handling.
+//config:
 //config:config ASH_JOB_CONTROL
 //config:      bool "Job control"
 //config:      default y
 
 #define JOBS ENABLE_ASH_JOB_CONTROL
 
-#include <setjmp.h>
 #include <fnmatch.h>
 #include <sys/times.h>
 #include <sys/utsname.h> /* for setting $HOSTNAME */
 #define IF_BASH_PATTERN_SUBST       IF_ASH_BASH_COMPAT
 #define    BASH_SUBSTR          ENABLE_ASH_BASH_COMPAT
 #define IF_BASH_SUBSTR              IF_ASH_BASH_COMPAT
-/* [[ EXPR ]] */
+/* BASH_TEST2: [[ EXPR ]]
+ * Status of [[ support:
+ * We replace && and || with -a and -o
+ * TODO:
+ * singleword+noglob expansion:
+ *   v='a b'; [[ $v = 'a b' ]]; echo 0:$?
+ *   [[ /bin/n* ]]; echo 0:$?
+ * -a/-o are not AND/OR ops! (they are just strings)
+ * quoting needs to be considered (-f is an operator, "-f" and ""-f are not; etc)
+ * = is glob match operator, not equality operator: STR = GLOB
+ * (in GLOB, quoting is significant on char-by-char basis: a*cd"*")
+ * == same as =
+ * add =~ regex match operator: STR =~ REGEX
+ */
 #define    BASH_TEST2           (ENABLE_ASH_BASH_COMPAT * ENABLE_ASH_TEST)
 #define    BASH_SOURCE          ENABLE_ASH_BASH_COMPAT
 #define    BASH_PIPEFAIL        ENABLE_ASH_BASH_COMPAT
 #define    BASH_HOSTNAME_VAR    ENABLE_ASH_BASH_COMPAT
 #define    BASH_SHLVL_VAR       ENABLE_ASH_BASH_COMPAT
+#define    BASH_XTRACEFD        ENABLE_ASH_BASH_COMPAT
+#define    BASH_READ_D          ENABLE_ASH_BASH_COMPAT
+#define IF_BASH_READ_D              IF_ASH_BASH_COMPAT
 
 #if defined(__ANDROID_API__) && __ANDROID_API__ <= 24
 /* Bionic at least up to version 24 has no glob() */
@@ -236,6 +267,12 @@ typedef long arith_t;
 # define IF_NOT_FEATURE_SH_STANDALONE(...) __VA_ARGS__
 #endif
 
+#ifndef F_DUPFD_CLOEXEC
+# define F_DUPFD_CLOEXEC F_DUPFD
+#endif
+#ifndef O_CLOEXEC
+# define O_CLOEXEC 0
+#endif
 #ifndef PIPE_BUF
 # define PIPE_BUF 4096           /* amount of buffering in a pipe */
 #endif
@@ -244,6 +281,19 @@ typedef long arith_t;
 # error "Do not even bother, ash will not run on NOMMU machine"
 #endif
 
+/* We use a trick to have more optimized code (fewer pointer reloads):
+ *  ash.c:   extern struct globals *const ash_ptr_to_globals;
+ *  ash_ptr_hack.c: struct globals *ash_ptr_to_globals;
+ * This way, compiler in ash.c knows the pointer can not change.
+ *
+ * However, this may break on weird arches or toolchains. In this case,
+ * set "-DBB_GLOBAL_CONST=''" in CONFIG_EXTRA_CFLAGS to disable
+ * this optimization.
+ */
+#ifndef BB_GLOBAL_CONST
+# define BB_GLOBAL_CONST const
+#endif
+
 
 /* ============ Hash table sizes. Configurable. */
 
@@ -309,6 +359,8 @@ struct globals_misc {
        /* shell level: 0 for the main shell, 1 for its children, and so on */
        int shlvl;
 #define rootshell (!shlvl)
+       int errlinno;
+
        char *minusc;  /* argument to -c option */
 
        char *curdir; // = nullstr;     /* current working directory */
@@ -365,7 +417,7 @@ struct globals_misc {
 #define S_DFL      1            /* default signal handling (SIG_DFL) */
 #define S_CATCH    2            /* signal is caught */
 #define S_IGN      3            /* signal is ignored (SIG_IGN) */
-#define S_HARD_IGN 4            /* signal is ignored permanently */
+#define S_HARD_IGN 4            /* signal is ignored permanently (it was SIG_IGN on entry to shell) */
 
        /* indicates specified signal received */
        uint8_t gotsig[NSIG - 1]; /* offset by 1: "signal" 0 is meaningless */
@@ -379,13 +431,14 @@ struct globals_misc {
 #endif
        pid_t backgndpid;        /* pid of last background process */
 };
-extern struct globals_misc *const ash_ptr_to_globals_misc;
+extern struct globals_misc *BB_GLOBAL_CONST ash_ptr_to_globals_misc;
 #define G_misc (*ash_ptr_to_globals_misc)
 #define exitstatus        (G_misc.exitstatus )
 #define back_exitstatus   (G_misc.back_exitstatus )
 #define job_warning       (G_misc.job_warning)
 #define rootpid     (G_misc.rootpid    )
 #define shlvl       (G_misc.shlvl      )
+#define errlinno    (G_misc.errlinno   )
 #define minusc      (G_misc.minusc     )
 #define curdir      (G_misc.curdir     )
 #define physdir     (G_misc.physdir    )
@@ -720,6 +773,7 @@ union node;
 
 struct ncmd {
        smallint type; /* Nxxxx */
+       int linno;
        union node *assign;
        union node *args;
        union node *redirect;
@@ -733,6 +787,7 @@ struct npipe {
 
 struct nredir {
        smallint type;
+       int linno;
        union node *n;
        union node *redirect;
 };
@@ -752,6 +807,7 @@ struct nif {
 
 struct nfor {
        smallint type;
+       int linno;
        union node *args;
        union node *body;
        char *var;
@@ -759,6 +815,7 @@ struct nfor {
 
 struct ncase {
        smallint type;
+       int linno;
        union node *expr;
        union node *cases;
 };
@@ -770,6 +827,13 @@ struct nclist {
        union node *body;
 };
 
+struct ndefun {
+       smallint type;
+       int linno;
+       char *text;
+       union node *body;
+};
+
 struct narg {
        smallint type;
        union node *next;
@@ -821,6 +885,7 @@ union node {
        struct nfor nfor;
        struct ncase ncase;
        struct nclist nclist;
+       struct ndefun ndefun;
        struct narg narg;
        struct nfile nfile;
        struct ndup ndup;
@@ -1226,6 +1291,10 @@ struct strpush {
        int unget;
 };
 
+/*
+ * The parsefile structure pointed to by the global variable parsefile
+ * contains information about the current file being read.
+ */
 struct parsefile {
        struct parsefile *prev; /* preceding file on stack */
        int linno;              /* current line */
@@ -1246,7 +1315,6 @@ struct parsefile {
 
 static struct parsefile basepf;        /* top level input file */
 static struct parsefile *g_parsefile = &basepf;  /* current input file */
-static int startlinno;                 /* line # where last token started */
 static char *commandname;              /* currently executing command */
 
 
@@ -1260,7 +1328,7 @@ ash_vmsg(const char *msg, va_list ap)
                if (strcmp(arg0, commandname))
                        fprintf(stderr, "%s: ", commandname);
                if (!iflag || g_parsefile->pf_fd > 0)
-                       fprintf(stderr, "line %d: ", startlinno);
+                       fprintf(stderr, "line %d: ", errlinno);
        }
        vfprintf(stderr, msg, ap);
        newline_and_flush(stderr);
@@ -1305,21 +1373,15 @@ ash_msg_and_raise_error(const char *msg, ...)
 }
 
 /*
- * Use '%m' to append error string on platforms that support it, '%s' and
- * strerror() on those that don't.
- *
  * 'fmt' must be a string literal.
  */
-#ifdef HAVE_PRINTF_PERCENTM
-#define ash_msg_and_raise_perror(fmt, ...) ash_msg_and_raise_error(fmt ": %m", ##__VA_ARGS__)
-#else
-#define ash_msg_and_raise_perror(fmt, ...) ash_msg_and_raise_error(fmt ": %s", ##__VA_ARGS__, strerror(errno))
-#endif
+#define ash_msg_and_raise_perror(fmt, ...) ash_msg_and_raise_error(fmt ": "STRERROR_FMT, ##__VA_ARGS__ STRERROR_ERRNO)
 
 static void raise_error_syntax(const char *) NORETURN;
 static void
 raise_error_syntax(const char *msg)
 {
+       errlinno = g_parsefile->linno;
        ash_msg_and_raise_error("syntax error: %s", msg);
        /* NOTREACHED */
 }
@@ -1442,7 +1504,7 @@ struct globals_memstack {
        size_t g_stacknleft; // = MINSIZE;
        struct stack_block stackbase;
 };
-extern struct globals_memstack *const ash_ptr_to_globals_memstack;
+extern struct globals_memstack *BB_GLOBAL_CONST ash_ptr_to_globals_memstack;
 #define G_memstack (*ash_ptr_to_globals_memstack)
 #define g_stackp     (G_memstack.g_stackp    )
 #define g_stacknxt   (G_memstack.g_stacknxt  )
@@ -1532,7 +1594,7 @@ sstrdup(const char *p)
        return memcpy(stalloc(len), p, len);
 }
 
-static inline void
+static ALWAYS_INLINE void
 grabstackblock(size_t len)
 {
        stalloc(len);
@@ -1899,10 +1961,6 @@ nextopt(const char *optstring)
 
 /* ============ Shell variables */
 
-/*
- * The parsefile structure pointed to by the global variable parsefile
- * contains information about the current file being read.
- */
 struct shparam {
        int nparam;             /* # of positional parameters (without $0) */
 #if ENABLE_ASH_GETOPTS
@@ -2011,6 +2069,7 @@ static const struct {
 #if ENABLE_ASH_GETOPTS
        { VSTRFIXED|VTEXTFIXED       , defoptindvar, getoptsreset    },
 #endif
+       { VSTRFIXED|VTEXTFIXED       , NULL /* inited to linenovar */, NULL },
 #if ENABLE_ASH_RANDOM_SUPPORT
        { VSTRFIXED|VTEXTFIXED|VUNSET|VDYNAMIC, "RANDOM", change_random },
 #endif
@@ -2031,25 +2090,18 @@ struct globals_var {
        int preverrout_fd;   /* stderr fd: usually 2, unless redirect moved it */
        struct var *vartab[VTABSIZE];
        struct var varinit[ARRAY_SIZE(varinit_data)];
+       int lineno;
+       char linenovar[sizeof("LINENO=") + sizeof(int)*3];
 };
-extern struct globals_var *const ash_ptr_to_globals_var;
+extern struct globals_var *BB_GLOBAL_CONST ash_ptr_to_globals_var;
 #define G_var (*ash_ptr_to_globals_var)
 #define shellparam    (G_var.shellparam   )
 //#define redirlist     (G_var.redirlist    )
 #define preverrout_fd (G_var.preverrout_fd)
 #define vartab        (G_var.vartab       )
 #define varinit       (G_var.varinit      )
-#define INIT_G_var() do { \
-       unsigned i; \
-       (*(struct globals_var**)&ash_ptr_to_globals_var) = xzalloc(sizeof(G_var)); \
-       barrier(); \
-       for (i = 0; i < ARRAY_SIZE(varinit_data); i++) { \
-               varinit[i].flags    = varinit_data[i].flags; \
-               varinit[i].var_text = varinit_data[i].var_text; \
-               varinit[i].var_func = varinit_data[i].var_func; \
-       } \
-} while (0)
-
+#define lineno        (G_var.lineno       )
+#define linenovar     (G_var.linenovar    )
 #define vifs      varinit[0]
 #if ENABLE_ASH_MAIL
 # define vmail    (&vifs)[1]
@@ -2063,14 +2115,28 @@ extern struct globals_var *const ash_ptr_to_globals_var;
 #define vps4      (&vps2)[1]
 #if ENABLE_ASH_GETOPTS
 # define voptind  (&vps4)[1]
+# define vlineno  (&voptind)[1]
 # if ENABLE_ASH_RANDOM_SUPPORT
-#  define vrandom (&voptind)[1]
+#  define vrandom (&vlineno)[1]
 # endif
 #else
+# define vlineno  (&vps4)[1]
 # if ENABLE_ASH_RANDOM_SUPPORT
-#  define vrandom (&vps4)[1]
+#  define vrandom (&vlineno)[1]
 # endif
 #endif
+#define INIT_G_var() do { \
+       unsigned i; \
+       (*(struct globals_var**)&ash_ptr_to_globals_var) = xzalloc(sizeof(G_var)); \
+       barrier(); \
+       for (i = 0; i < ARRAY_SIZE(varinit_data); i++) { \
+               varinit[i].flags    = varinit_data[i].flags; \
+               varinit[i].var_text = varinit_data[i].var_text; \
+               varinit[i].var_func = varinit_data[i].var_func; \
+       } \
+       strcpy(linenovar, "LINENO="); \
+       vlineno.var_text = linenovar; \
+} while (0)
 
 /*
  * The following macros access the values of the above variables.
@@ -2096,7 +2162,9 @@ extern struct globals_var *const ash_ptr_to_globals_var;
 static void FAST_FUNC
 getoptsreset(const char *value)
 {
-       shellparam.optind = number(value) ?: 1;
+       shellparam.optind = 1;
+       if (is_number(value))
+               shellparam.optind = number(value) ?: 1;
        shellparam.optoff = -1;
 }
 #endif
@@ -2204,8 +2272,12 @@ lookupvar(const char *name)
                if (v->flags & VDYNAMIC)
                        v->var_func(NULL);
 #endif
-               if (!(v->flags & VUNSET))
+               if (!(v->flags & VUNSET)) {
+                       if (v == &vlineno && v->var_text == linenovar) {
+                               fmtstr(linenovar+7, sizeof(linenovar)-7, "%d", lineno);
+                       }
                        return var_end(v->var_text);
+               }
        }
        return NULL;
 }
@@ -2382,8 +2454,11 @@ listsetvar(struct strlist *list_set_var, int flags)
 /*
  * Generate a list of variables satisfying the given conditions.
  */
+#if !ENABLE_FEATURE_SH_NOFORK
+# define listvars(on, off, lp, end) listvars(on, off, end)
+#endif
 static char **
-listvars(int on, int off, char ***end)
+listvars(int on, int off, struct strlist *lp, char ***end)
 {
        struct var **vpp;
        struct var *vp;
@@ -2396,12 +2471,40 @@ listvars(int on, int off, char ***end)
        do {
                for (vp = *vpp; vp; vp = vp->next) {
                        if ((vp->flags & mask) == on) {
+#if ENABLE_FEATURE_SH_NOFORK
+                               /* If variable with the same name is both
+                                * exported and temporarily set for a command:
+                                *  export ZVAR=5
+                                *  ZVAR=6 printenv
+                                * then "ZVAR=6" will be both in vartab and
+                                * lp lists. Do not pass it twice to printenv.
+                                */
+                               struct strlist *lp1 = lp;
+                               while (lp1) {
+                                       if (strcmp(lp1->text, vp->var_text) == 0)
+                                               goto skip;
+                                       lp1 = lp1->next;
+                               }
+#endif
                                if (ep == stackstrend())
                                        ep = growstackstr();
                                *ep++ = (char*)vp->var_text;
+#if ENABLE_FEATURE_SH_NOFORK
+ skip: ;
+#endif
                        }
                }
        } while (++vpp < vartab + VTABSIZE);
+
+#if ENABLE_FEATURE_SH_NOFORK
+       while (lp) {
+               if (ep == stackstrend())
+                       ep = growstackstr();
+               *ep++ = lp->text;
+               lp = lp->next;
+       }
+#endif
+
        if (ep == stackstrend())
                ep = growstackstr();
        if (end)
@@ -2743,7 +2846,7 @@ cdcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
        goto docd;
 
  err:
-       ash_msg_and_raise_error("can't cd to %s", dest);
+       ash_msg_and_raise_perror("can't cd to %s", dest);
        /* NOTREACHED */
  out:
        if (flags & CD_PRINT)
@@ -3536,9 +3639,12 @@ setsignal(int signo)
 #endif
                }
        }
-//TODO: if !rootshell, we reset SIGQUIT to DFL,
-//whereas we have to restore it to what shell got on entry
-//from the parent. See comment above
+       /* if !rootshell, we reset SIGQUIT to DFL,
+        * whereas we have to restore it to what shell got on entry.
+        * This is handled by the fact that if signal was IGNored on entry,
+        * then cur_act is S_HARD_IGN and we never change its sigaction
+        * (see code below).
+        */
 
        if (signo == SIGCHLD)
                new_act = S_CATCH;
@@ -3562,10 +3668,18 @@ setsignal(int signo)
                                cur_act = S_IGN;   /* don't hard ignore these */
                        }
                }
+               if (act.sa_handler == SIG_DFL && new_act == S_DFL) {
+                       /* installing SIG_DFL over SIG_DFL is a no-op */
+                       /* saves one sigaction call in each "sh -c SCRIPT" invocation */
+                       *t = S_DFL;
+                       return;
+               }
        }
        if (cur_act == S_HARD_IGN || cur_act == new_act)
                return;
 
+       *t = new_act;
+
        act.sa_handler = SIG_DFL;
        switch (new_act) {
        case S_CATCH:
@@ -3575,16 +3689,13 @@ setsignal(int signo)
                act.sa_handler = SIG_IGN;
                break;
        }
-
        /* flags and mask matter only if !DFL and !IGN, but we do it
         * for all cases for more deterministic behavior:
         */
-       act.sa_flags = 0;
+       act.sa_flags = 0; //TODO: why not SA_RESTART?
        sigfillset(&act.sa_mask);
 
        sigaction_set(signo, &act);
-
-       *t = new_act;
 }
 
 /* mode flags for set_curjob */
@@ -3876,12 +3987,13 @@ setjobctl(int on)
                                        goto out;
                }
                /* fd is a tty at this point */
-               fd = fcntl(fd, F_DUPFD, 10);
+               fd = fcntl(fd, F_DUPFD_CLOEXEC, 10);
                if (ofd >= 0) /* if it is "/dev/tty", close. If 0/1/2, don't */
                        close(ofd);
                if (fd < 0)
                        goto out; /* F_DUPFD failed */
-               close_on_exec_on(fd);
+               if (F_DUPFD_CLOEXEC == F_DUPFD) /* if old libc (w/o F_DUPFD_CLOEXEC) */
+                       close_on_exec_on(fd);
                while (1) { /* while we are in the background */
                        pgrp = tcgetpgrp(fd);
                        if (pgrp < 0) {
@@ -4770,7 +4882,7 @@ cmdtxt(union node *n)
                p = "; done";
                goto dodo;
        case NDEFUN:
-               cmdputs(n->narg.text);
+               cmdputs(n->ndefun.text);
                p = "() { ... }";
                goto dotail2;
        case NCMD:
@@ -4981,7 +5093,7 @@ forkchild(struct job *jp, union node *n, int mode)
                if (jp->nprocs == 0) {
                        close(0);
                        if (open(bb_dev_null, O_RDONLY) != 0)
-                               ash_msg_and_raise_error("can't open '%s'", bb_dev_null);
+                               ash_msg_and_raise_perror("can't open '%s'", bb_dev_null);
                }
        }
        if (oldlvl == 0) {
@@ -5070,7 +5182,7 @@ forkshell(struct job *jp, union node *n, int mode)
                TRACE(("Fork failed, errno=%d", errno));
                if (jp)
                        freejob(jp);
-               ash_msg_and_raise_error("can't fork");
+               ash_msg_and_raise_perror("can't fork");
        }
        if (pid == 0) {
                CLEAR_RANDOM_T(&random_gen); /* or else $RANDOM repeats in child */
@@ -5213,7 +5325,7 @@ openhere(union node *redir)
        size_t len = 0;
 
        if (pipe(pip) < 0)
-               ash_msg_and_raise_error("pipe call failed");
+               ash_msg_and_raise_perror("can't create pipe");
        if (redir->type == NHERE) {
                len = strlen(redir->nhere.doc->narg.text);
                if (len <= PIPE_BUF) {
@@ -5291,7 +5403,7 @@ openredirect(union node *redir)
                                f = open(fname, O_WRONLY, 0666);
                                if (f < 0)
                                        goto ecreate;
-                               if (fstat(f, &sb) < 0 && S_ISREG(sb.st_mode)) {
+                               if (!fstat(f, &sb) && S_ISREG(sb.st_mode)) {
                                        close(f);
                                        errno = EEXIST;
                                        goto ecreate;
@@ -5331,13 +5443,14 @@ savefd(int from)
        int newfd;
        int err;
 
-       newfd = fcntl(from, F_DUPFD, 10);
+       newfd = fcntl(from, F_DUPFD_CLOEXEC, 10);
        err = newfd < 0 ? errno : 0;
        if (err != EBADF) {
                if (err)
                        ash_msg_and_raise_perror("%d", from);
                close(from);
-               fcntl(newfd, F_SETFD, FD_CLOEXEC);
+               if (F_DUPFD_CLOEXEC == F_DUPFD)
+                       close_on_exec_on(newfd);
        }
 
        return newfd;
@@ -5355,12 +5468,15 @@ dup2_or_raise(int from, int to)
        return newfd;
 }
 static int
-fcntl_F_DUPFD(int fd, int avoid_fd)
+dup_CLOEXEC(int fd, int avoid_fd)
 {
        int newfd;
  repeat:
-       newfd = fcntl(fd, F_DUPFD, avoid_fd + 1);
-       if (newfd < 0) {
+       newfd = fcntl(fd, F_DUPFD_CLOEXEC, avoid_fd + 1);
+       if (newfd >= 0) {
+               if (F_DUPFD_CLOEXEC == F_DUPFD) /* if old libc (w/o F_DUPFD_CLOEXEC) */
+                       close_on_exec_on(newfd);
+       } else { /* newfd < 0 */
                if (errno == EBUSY)
                        goto repeat;
                if (errno == EINTR)
@@ -5373,7 +5489,7 @@ xdup_CLOEXEC_and_close(int fd, int avoid_fd)
 {
        int newfd;
  repeat:
-       newfd = fcntl(fd, F_DUPFD, avoid_fd + 1);
+       newfd = fcntl(fd, F_DUPFD_CLOEXEC, avoid_fd + 1);
        if (newfd < 0) {
                if (errno == EBUSY)
                        goto repeat;
@@ -5384,7 +5500,8 @@ xdup_CLOEXEC_and_close(int fd, int avoid_fd)
                        return fd;
                ash_msg_and_raise_perror("%d", newfd);
        }
-       fcntl(newfd, F_SETFD, FD_CLOEXEC);
+       if (F_DUPFD_CLOEXEC == F_DUPFD)
+               close_on_exec_on(newfd);
        close(fd);
        return newfd;
 }
@@ -5476,7 +5593,7 @@ save_fd_on_redirect(int fd, int avoid_fd, struct redirtab *sq)
        for (i = 0; sq->two_fd[i].orig_fd != EMPTY; i++) {
                /* If we collide with an already moved fd... */
                if (fd == sq->two_fd[i].moved_to) {
-                       new_fd = fcntl_F_DUPFD(fd, avoid_fd);
+                       new_fd = dup_CLOEXEC(fd, avoid_fd);
                        sq->two_fd[i].moved_to = new_fd;
                        TRACE(("redirect_fd %d: already busy, moving to %d\n", fd, new_fd));
                        if (new_fd < 0) /* what? */
@@ -5491,7 +5608,7 @@ save_fd_on_redirect(int fd, int avoid_fd, struct redirtab *sq)
        }
 
        /* If this fd is open, we move and remember it; if it's closed, new_fd = CLOSED (-1) */
-       new_fd = fcntl_F_DUPFD(fd, avoid_fd);
+       new_fd = dup_CLOEXEC(fd, avoid_fd);
        TRACE(("redirect_fd %d: previous fd is moved to %d (-1 if it was closed)\n", fd, new_fd));
        if (new_fd < 0) {
                if (errno != EBADF)
@@ -5544,12 +5661,10 @@ static void
 redirect(union node *redir, int flags)
 {
        struct redirtab *sv;
-       int sv_pos;
 
        if (!redir)
                return;
 
-       sv_pos = 0;
        sv = NULL;
        INT_OFF;
        if (flags & REDIR_PUSH)
@@ -5745,6 +5860,26 @@ ash_arith(const char *s)
        return result;
 }
 #endif
+#if BASH_SUBSTR
+# if ENABLE_FEATURE_SH_MATH
+static int substr_atoi(const char *s)
+{
+       arith_t t = ash_arith(s);
+       if (sizeof(t) > sizeof(int)) {
+               /* clamp very large or very large negative nums for ${v:N:M}:
+                * else "${v:0:0x100000001}" would work as "${v:0:1}"
+                */
+               if (t > INT_MAX)
+                       t = INT_MAX;
+               if (t < INT_MIN)
+                       t = INT_MIN;
+       }
+       return t;
+}
+# else
+#  define substr_atoi(s) number(s)
+# endif
+#endif
 
 /*
  * expandarg flags
@@ -5765,10 +5900,9 @@ ash_arith(const char *s)
  * performs globbing, and thus diverges from what we do).
  */
 #define EXP_CASE        0x10    /* keeps quotes around for CASE pattern */
-#define EXP_QPAT        0x20    /* pattern in quoted parameter expansion */
-#define EXP_VARTILDE2   0x40    /* expand tildes after colons only */
-#define EXP_WORD        0x80    /* expand word in parameter expansion */
-#define EXP_QUOTED      0x100   /* expand word in double quotes */
+#define EXP_VARTILDE2   0x20    /* expand tildes after colons only */
+#define EXP_WORD        0x40    /* expand word in parameter expansion */
+#define EXP_QUOTED      0x80    /* expand word in double quotes */
 /*
  * rmescape() flags
  */
@@ -5776,10 +5910,9 @@ ash_arith(const char *s)
 #define RMESCAPE_GLOB   0x2     /* Add backslashes for glob */
 #define RMESCAPE_GROW   0x8     /* Grow strings instead of stalloc */
 #define RMESCAPE_HEAP   0x10    /* Malloc strings instead of stalloc */
-#define RMESCAPE_SLASH  0x20    /* Stop globbing after slash */
 
 /* Add CTLESC when necessary. */
-#define QUOTES_ESC     (EXP_FULL | EXP_CASE | EXP_QPAT)
+#define QUOTES_ESC     (EXP_FULL | EXP_CASE)
 /* Do not skip NUL characters. */
 #define QUOTES_KEEPNUL EXP_TILDE
 
@@ -5854,7 +5987,10 @@ ifsbreakup(char *string, struct arglist *arglist)
                realifs = ifsset() ? ifsval() : defifs;
                ifsp = &ifsfirst;
                do {
+                       int afternul;
+
                        p = string + ifsp->begoff;
+                       afternul = nulonly;
                        nulonly = ifsp->nulonly;
                        ifs = nulonly ? nullstr : realifs;
                        ifsspc = 0;
@@ -5866,7 +6002,7 @@ ifsbreakup(char *string, struct arglist *arglist)
                                        p++;
                                        continue;
                                }
-                               if (!nulonly)
+                               if (!(afternul || nulonly))
                                        ifsspc = (strchr(defifs, *p) != NULL);
                                /* Ignore IFS whitespace at start */
                                if (q == start && ifsspc) {
@@ -5957,19 +6093,21 @@ esclen(const char *start, const char *p)
 /*
  * Remove any CTLESC characters from a string.
  */
+#if !BASH_PATTERN_SUBST
+#define rmescapes(str, flag, slash_position) \
+       rmescapes(str, flag)
+#endif
 static char *
-rmescapes(char *str, int flag)
+rmescapes(char *str, int flag, int *slash_position)
 {
        static const char qchars[] ALIGN1 = {
                IF_BASH_PATTERN_SUBST('/',) CTLESC, CTLQUOTEMARK, '\0' };
 
        char *p, *q, *r;
-       unsigned inquotes;
        unsigned protect_against_glob;
        unsigned globbing;
-       IF_BASH_PATTERN_SUBST(unsigned slash = flag & RMESCAPE_SLASH;)
 
-       p = strpbrk(str, qchars IF_BASH_PATTERN_SUBST(+ !slash));
+       p = strpbrk(str, qchars IF_BASH_PATTERN_SUBST(+ !slash_position));
        if (!p)
                return str;
 
@@ -5996,18 +6134,21 @@ rmescapes(char *str, int flag)
                }
        }
 
-       inquotes = 0;
        globbing = flag & RMESCAPE_GLOB;
        protect_against_glob = globbing;
        while (*p) {
                if ((unsigned char)*p == CTLQUOTEMARK) {
-// Note: both inquotes and protect_against_glob only affect whether
+// Note: protect_against_glob only affect whether
 // CTLESC,<ch> gets converted to <ch> or to \<ch>
-                       inquotes = ~inquotes;
                        p++;
                        protect_against_glob = globbing;
                        continue;
                }
+               if (*p == '\\') {
+                       /* naked back slash */
+                       protect_against_glob = 0;
+                       goto copy;
+               }
                if ((unsigned char)*p == CTLESC) {
                        p++;
 #if DEBUG
@@ -6033,26 +6174,23 @@ rmescapes(char *str, int flag)
                                if (*p == '*'
                                 || *p == '?'
                                 || *p == '['
-                                || *p == '\\' /* case '\' in \\ ) echo ok;; *) echo WRONG;; esac */
-                                || *p == ']' /* case ']' in [a\]] ) echo ok;; *) echo WRONG;; esac */
-                                || *p == '-' /* case '-' in [a\-c]) echo ok;; *) echo WRONG;; esac */
-                                || *p == '!' /* case '!' in [\!] ) echo ok;; *) echo WRONG;; esac */
+                                || *p == '\\' /* case '\' in \\    ) echo ok;; *) echo WRONG;; esac */
+                                || *p == ']'  /* case ']' in [a\]] ) echo ok;; *) echo WRONG;; esac */
+                                || *p == '-'  /* case '-' in [a\-c]) echo ok;; *) echo WRONG;; esac */
+                                || *p == '!'  /* case '!' in [\!]  ) echo ok;; *) echo WRONG;; esac */
                                /* Some libc support [^negate], that's why "^" also needs love */
-                                || *p == '^' /* case '^' in [\^] ) echo ok;; *) echo WRONG;; esac */
+                                || *p == '^'  /* case '^' in [\^]  ) echo ok;; *) echo WRONG;; esac */
                                ) {
                                        *q++ = '\\';
                                }
                        }
-               } else if (*p == '\\' && !inquotes) {
-                       /* naked back slash */
-                       protect_against_glob = 0;
-                       goto copy;
                }
 #if BASH_PATTERN_SUBST
-               else if (*p == '/' && slash) {
-                       /* stop handling globbing and mark location of slash */
-                       globbing = slash = 0;
-                       *p = CTLESC;
+               else if (slash_position && p == str + *slash_position) {
+                       /* stop handling globbing */
+                       globbing = 0;
+                       *slash_position = q - r;
+                       slash_position = NULL;
                }
 #endif
                protect_against_glob = globbing;
@@ -6076,7 +6214,7 @@ rmescapes(char *str, int flag)
 static char *
 preglob(const char *pattern, int flag)
 {
-       return rmescapes((char *)pattern, flag | RMESCAPE_GLOB);
+       return rmescapes((char *)pattern, flag | RMESCAPE_GLOB, NULL);
 }
 
 /*
@@ -6277,7 +6415,7 @@ evalbackcmd(union node *n, struct backcmd *result)
        }
 
        if (pipe(pip) < 0)
-               ash_msg_and_raise_error("pipe call failed");
+               ash_msg_and_raise_perror("can't create pipe");
        jp = makejob(/*n,*/ 1);
        if (forkshell(jp, n, FORK_NOJOB) == 0) {
                /* child */
@@ -6419,7 +6557,7 @@ expari(int flag)
        expdest = p;
 
        if (flag & QUOTES_ESC)
-               rmescapes(p + 1, 0);
+               rmescapes(p + 1, 0, NULL);
 
        len = cvtnum(ash_arith(p + 1));
 
@@ -6527,12 +6665,12 @@ argstr(char *p, int flags)
                case CTLENDVAR: /* ??? */
                        goto breakloop;
                case CTLQUOTEMARK:
-                       inquotes ^= EXP_QUOTED;
                        /* "$@" syntax adherence hack */
-                       if (inquotes && !memcmp(p, dolatstr + 1, DOLATSTRLEN - 1)) {
-                               p = evalvar(p + 1, flags | inquotes) + 1;
+                       if (!inquotes && !memcmp(p, dolatstr + 1, DOLATSTRLEN - 1)) {
+                               p = evalvar(p + 1, flags | EXP_QUOTED) + 1;
                                goto start;
                        }
+                       inquotes ^= EXP_QUOTED;
  addquote:
                        if (flags & QUOTES_ESC) {
                                p--;
@@ -6543,16 +6681,6 @@ argstr(char *p, int flags)
                case CTLESC:
                        startloc++;
                        length++;
-
-                       /*
-                        * Quoted parameter expansion pattern: remove quote
-                        * unless inside inner quotes or we have a literal
-                        * backslash.
-                        */
-                       if (((flags | inquotes) & (EXP_QPAT | EXP_QUOTED)) ==
-                           EXP_QPAT && *p != '\\')
-                               break;
-
                        goto addquote;
                case CTLVAR:
                        TRACE(("argstr: evalvar('%s')\n", p));
@@ -6707,20 +6835,67 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
        char *rmesc, *rmescend;
        char *str;
        int amount, resetloc;
+       int argstr_flags;
        IF_BASH_PATTERN_SUBST(int workloc;)
-       IF_BASH_PATTERN_SUBST(char *repl = NULL;)
+       IF_BASH_PATTERN_SUBST(int slash_pos;)
+       IF_BASH_PATTERN_SUBST(char *repl;)
        int zero;
        char *(*scan)(char*, char*, char*, char*, int, int);
 
        //bb_error_msg("subevalvar(p:'%s',varname:'%s',strloc:%d,subtype:%d,startloc:%d,varflags:%x,quotes:%d)",
        //              p, varname, strloc, subtype, startloc, varflags, quotes);
 
-       argstr(p, EXP_TILDE | (subtype != VSASSIGN && subtype != VSQUESTION ?
-                       (flag & (EXP_QUOTED | EXP_QPAT) ? EXP_QPAT : EXP_CASE) : 0)
-       );
+#if BASH_PATTERN_SUBST
+       /* For "${v/pattern/repl}", we must find the delimiter _before_
+        * argstr() call expands possible variable references in pattern:
+        * think about "v=a; a=a/; echo ${v/$a/r}" case.
+        */
+       repl = NULL;
+       if (subtype == VSREPLACE || subtype == VSREPLACEALL) {
+               /* Find '/' and replace with NUL */
+               repl = p;
+               for (;;) {
+                       /* Handle escaped slashes, e.g. "${v/\//_}" (they are CTLESC'ed by this point) */
+                       if (*repl == '\0') {
+                               repl = NULL;
+                               break;
+                       }
+                       if (*repl == '/') {
+                               *repl = '\0';
+                               break;
+                       }
+                       if ((unsigned char)*repl == CTLESC && repl[1])
+                               repl++;
+                       repl++;
+               }
+       }
+#endif
+       argstr_flags = EXP_TILDE;
+       if (subtype != VSASSIGN
+        && subtype != VSQUESTION
+#if BASH_SUBSTR
+        && subtype != VSSUBSTR
+#endif
+       ) {
+               /* EXP_CASE keeps CTLESC's */
+               argstr_flags = EXP_TILDE | EXP_CASE;
+       }
+       argstr(p, argstr_flags);
+       //bb_error_msg("str0:'%s'", (char *)stackblock() + strloc);
+#if BASH_PATTERN_SUBST
+       slash_pos = -1;
+       if (repl) {
+               slash_pos = expdest - ((char *)stackblock() + strloc);
+               STPUTC('/', expdest);
+               //bb_error_msg("repl+1:'%s'", repl + 1);
+               argstr(repl + 1, EXP_TILDE); /* EXP_TILDE: echo "${v/x/~}" expands ~ ! */
+               *repl = '/';
+       }
+#endif
        STPUTC('\0', expdest);
        argbackq = saveargbackq;
        startp = (char *)stackblock() + startloc;
+       //bb_error_msg("str1:'%s'", (char *)stackblock() + strloc);
 
        switch (subtype) {
        case VSASSIGN:
@@ -6740,13 +6915,10 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
 
                loc = str = stackblock() + strloc;
 
-# if !ENABLE_FEATURE_SH_MATH
-#  define ash_arith number
-# endif
                /* Read POS in ${var:POS:LEN} */
                colon = strchr(loc, ':');
                if (colon) *colon = '\0';
-               pos = ash_arith(loc);
+               pos = substr_atoi(loc);
                if (colon) *colon = ':';
 
                /* Read LEN in ${var:POS:LEN} */
@@ -6754,7 +6926,6 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
                /* *loc != '\0', guaranteed by parser */
                if (quotes) {
                        char *ptr;
-
                        /* Adjust the length by the number of escapes */
                        for (ptr = startp; ptr < (str - 1); ptr++) {
                                if ((unsigned char)*ptr == CTLESC) {
@@ -6766,19 +6937,15 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
                orig_len = len;
                if (*loc++ == ':') {
                        /* ${var::LEN} */
-                       len = ash_arith(loc);
+                       len = substr_atoi(loc);
                } else {
                        /* Skip POS in ${var:POS:LEN} */
                        len = orig_len;
-                       while (*loc && *loc != ':') {
+                       while (*loc && *loc != ':')
                                loc++;
-                       }
-                       if (*loc++ == ':') {
-                               len = ash_arith(loc);
-                       }
+                       if (*loc++ == ':')
+                               len = substr_atoi(loc);
                }
-#  undef ash_arith
-
                if (pos < 0) {
                        /* ${VAR:$((-n)):l} starts n chars from the end */
                        pos = orig_len + pos;
@@ -6818,6 +6985,8 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
        resetloc = expdest - (char *)stackblock();
 
 #if BASH_PATTERN_SUBST
+       repl = NULL;
+
        /* We'll comeback here if we grow the stack while handling
         * a VSREPLACE or VSREPLACEALL, since our pointers into the
         * stack will need rebasing, and we'll need to remove our work
@@ -6832,8 +7001,10 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
 
        rmesc = startp;
        rmescend = (char *)stackblock() + strloc;
+       //bb_error_msg("str7:'%s'", rmescend);
        if (quotes) {
-               rmesc = rmescapes(startp, RMESCAPE_ALLOC | RMESCAPE_GROW);
+//TODO: how to handle slash_pos here if string changes (shortens?)
+               rmesc = rmescapes(startp, RMESCAPE_ALLOC | RMESCAPE_GROW, NULL);
                if (rmesc != startp) {
                        rmescend = expdest;
                        startp = (char *)stackblock() + startloc;
@@ -6846,12 +7017,13 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
         * The result is a_\_z_c (not a\_\_z_c)!
         *
         * The search pattern and replace string treat backslashes differently!
-        * RMESCAPE_SLASH causes preglob to work differently on the pattern
+        * "&slash_pos" causes rmescapes() to work differently on the pattern
         * and string.  It's only used on the first call.
         */
-       preglob(str, IF_BASH_PATTERN_SUBST(
-               (subtype == VSREPLACE || subtype == VSREPLACEALL) && !repl ?
-                       RMESCAPE_SLASH : ) 0);
+       //bb_error_msg("str8:'%s' slash_pos:%d", str, slash_pos);
+       rmescapes(str, RMESCAPE_GLOB,
+               repl ? NULL : (slash_pos < 0 ? NULL : &slash_pos)
+       );
 
 #if BASH_PATTERN_SUBST
        workloc = expdest - (char *)stackblock();
@@ -6860,11 +7032,12 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
                char *idx, *end;
 
                if (!repl) {
-                       repl = strchr(str, CTLESC);
-                       if (repl)
+                       //bb_error_msg("str9:'%s' slash_pos:%d", str, slash_pos);
+                       repl = nullstr;
+                       if (slash_pos >= 0) {
+                               repl = str + slash_pos;
                                *repl++ = '\0';
-                       else
-                               repl = nullstr;
+                       }
                }
                //bb_error_msg("str:'%s' repl:'%s'", str, repl);
 
@@ -7030,7 +7203,7 @@ varvalue(char *name, int varflags, int flags, int *quotedp)
        case '-':
                expdest = makestrspace(NOPTS, expdest);
                for (i = NOPTS - 1; i >= 0; i--) {
-                       if (optlist[i]) {
+                       if (optlist[i] && optletters(i)) {
                                USTPUTC(optletters(i), expdest);
                                len++;
                        }
@@ -7277,13 +7450,13 @@ hasmeta(const char *p)
                p = strpbrk(p, chars);
                if (!p)
                        break;
-               switch ((unsigned char) *p) {
+               switch ((unsigned char)*p) {
                case CTLQUOTEMARK:
                        for (;;) {
                                p++;
-                               if (*p == CTLQUOTEMARK)
+                               if ((unsigned char)*p == CTLQUOTEMARK)
                                        break;
-                               if (*p == CTLESC)
+                               if ((unsigned char)*p == CTLESC)
                                        p++;
                                if (*p == '\0') /* huh? */
                                        return 0;
@@ -7384,7 +7557,7 @@ expandmeta(struct strlist *str /*, int flag*/)
                        INT_ON;
  nometa:
                        *exparg.lastp = str;
-                       rmescapes(str->text, 0);
+                       rmescapes(str->text, 0, NULL);
                        exparg.lastp = &str->next;
                        break;
                default:        /* GLOB_NOSPACE */
@@ -7402,9 +7575,16 @@ expandmeta(struct strlist *str /*, int flag*/)
 /*
  * Do metacharacter (i.e. *, ?, [...]) expansion.
  */
+typedef struct exp_t {
+       char *dir;
+       unsigned dir_max;
+} exp_t;
 static void
-expmeta(char *expdir, char *enddir, char *name)
+expmeta(exp_t *exp, char *name, unsigned name_len, unsigned expdir_len)
 {
+#define expdir exp->dir
+#define expdir_max exp->dir_max
+       char *enddir = expdir + expdir_len;
        char *p;
        const char *cp;
        char *start;
@@ -7447,15 +7627,15 @@ expmeta(char *expdir, char *enddir, char *name)
                }
        }
        if (metaflag == 0) {    /* we've reached the end of the file name */
-               if (enddir != expdir)
-                       metaflag++;
+               if (!expdir_len)
+                       return;
                p = name;
                do {
                        if (*p == '\\')
                                p++;
                        *enddir++ = *p;
                } while (*p++);
-               if (metaflag == 0 || lstat(expdir, &statb) >= 0)
+               if (lstat(expdir, &statb) == 0)
                        addfname(expdir);
                return;
        }
@@ -7468,19 +7648,14 @@ expmeta(char *expdir, char *enddir, char *name)
                        *enddir++ = *p++;
                } while (p < start);
        }
-       if (enddir == expdir) {
+       *enddir = '\0';
+       cp = expdir;
+       expdir_len = enddir - cp;
+       if (!expdir_len)
                cp = ".";
-       } else if (enddir == expdir + 1 && *expdir == '/') {
-               cp = "/";
-       } else {
-               cp = expdir;
-               enddir[-1] = '\0';
-       }
        dirp = opendir(cp);
        if (dirp == NULL)
                return;
-       if (enddir != expdir)
-               enddir[-1] = '/';
        if (*endname == 0) {
                atend = 1;
        } else {
@@ -7488,6 +7663,7 @@ expmeta(char *expdir, char *enddir, char *name)
                *endname = '\0';
                endname += esc + 1;
        }
+       name_len -= endname - name;
        matchdot = 0;
        p = start;
        if (*p == '\\')
@@ -7502,16 +7678,30 @@ expmeta(char *expdir, char *enddir, char *name)
                                strcpy(enddir, dp->d_name);
                                addfname(expdir);
                        } else {
-                               for (p = enddir, cp = dp->d_name; (*p++ = *cp++) != '\0';)
-                                       continue;
-                               p[-1] = '/';
-                               expmeta(expdir, p, endname);
+                               unsigned offset;
+                               unsigned len;
+
+                               p = stpcpy(enddir, dp->d_name);
+                               *p = '/';
+
+                               offset = p - expdir + 1;
+                               len = offset + name_len + NAME_MAX;
+                               if (len > expdir_max) {
+                                       len += PATH_MAX;
+                                       expdir = ckrealloc(expdir, len);
+                                       expdir_max = len;
+                               }
+
+                               expmeta(exp, endname, name_len, offset);
+                               enddir = expdir + expdir_len;
                        }
                }
        }
        closedir(dirp);
        if (!atend)
                endname[-esc - 1] = esc ? '\\' : '/';
+#undef expdir
+#undef expdir_max
 }
 
 static struct strlist *
@@ -7584,10 +7774,11 @@ expandmeta(struct strlist *str /*, int flag*/)
        /* TODO - EXP_REDIR */
 
        while (str) {
-               char *expdir;
+               exp_t exp;
                struct strlist **savelastp;
                struct strlist *sp;
                char *p;
+               unsigned len;
 
                if (fflag)
                        goto nometa;
@@ -7597,13 +7788,12 @@ expandmeta(struct strlist *str /*, int flag*/)
 
                INT_OFF;
                p = preglob(str->text, RMESCAPE_ALLOC | RMESCAPE_HEAP);
-               {
-                       int i = strlen(str->text);
-//BUGGY estimation of how long expanded name can be
-                       expdir = ckmalloc(i < 2048 ? 2048 : i+1);
-               }
-               expmeta(expdir, expdir, p);
-               free(expdir);
+               len = strlen(p);
+               exp.dir_max = len + PATH_MAX;
+               exp.dir = ckmalloc(exp.dir_max);
+
+               expmeta(&exp, p, len, 0);
+               free(exp.dir);
                if (p != str->text)
                        free(p);
                INT_ON;
@@ -7613,7 +7803,7 @@ expandmeta(struct strlist *str /*, int flag*/)
                         */
  nometa:
                        *exparg.lastp = str;
-                       rmescapes(str->text, 0);
+                       rmescapes(str->text, 0, NULL);
                        exparg.lastp = &str->next;
                } else {
                        *exparg.lastp = NULL;
@@ -7693,8 +7883,9 @@ static int
 patmatch(char *pattern, const char *string)
 {
        char *p = preglob(pattern, 0);
-       //bb_error_msg("fnmatch(pattern:'%s',str:'%s')", p, string);
-       return pmatch(p, string);
+       int r = pmatch(p, string);
+       //bb_error_msg("!fnmatch(pattern:'%s',str:'%s',0):%d", p, string, r);
+       return r;
 }
 
 /*
@@ -7796,7 +7987,7 @@ tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) const char *cmd, char **argv, c
                        while (*envp)
                                putenv(*envp++);
                        popredir(/*drop:*/ 1);
-                       run_applet_no_and_exit(applet_no, cmd, argv);
+                       run_noexec_applet_and_exit(applet_no, cmd, argv);
                }
                /* re-exec ourselves with the new arguments */
                execve(bb_busybox_exec_path, argv, envp);
@@ -7855,7 +8046,7 @@ static void shellexec(char *prog, char **argv, const char *path, int idx)
        int exerrno;
        int applet_no = -1; /* used only by FEATURE_SH_STANDALONE */
 
-       envp = listvars(VEXPORT, VUNSET, /*end:*/ NULL);
+       envp = listvars(VEXPORT, VUNSET, /*strlist:*/ NULL, /*end:*/ NULL);
        if (strchr(prog, '/') != NULL
 #if ENABLE_FEATURE_SH_STANDALONE
         || (applet_no = find_applet_by_name(prog)) >= 0
@@ -8539,6 +8730,9 @@ calcsize(int funcblocksize, union node *n)
                funcblocksize = calcsize(funcblocksize, n->nclist.next);
                break;
        case NDEFUN:
+               funcblocksize = calcsize(funcblocksize, n->ndefun.body);
+               funcblocksize += SHELL_ALIGN(strlen(n->ndefun.text) + 1);
+               break;
        case NARG:
                funcblocksize = sizenodelist(funcblocksize, n->narg.backquote);
                funcblocksize += SHELL_ALIGN(strlen(n->narg.text) + 1); /* was funcstringsize += ... */
@@ -8614,6 +8808,7 @@ copynode(union node *n)
                new->ncmd.redirect = copynode(n->ncmd.redirect);
                new->ncmd.args = copynode(n->ncmd.args);
                new->ncmd.assign = copynode(n->ncmd.assign);
+               new->ncmd.linno = n->ncmd.linno;
                break;
        case NPIPE:
                new->npipe.cmdlist = copynodelist(n->npipe.cmdlist);
@@ -8624,6 +8819,7 @@ copynode(union node *n)
        case NSUBSHELL:
                new->nredir.redirect = copynode(n->nredir.redirect);
                new->nredir.n = copynode(n->nredir.n);
+               new->nredir.linno = n->nredir.linno;
                break;
        case NAND:
        case NOR:
@@ -8642,10 +8838,12 @@ copynode(union node *n)
                new->nfor.var = nodeckstrdup(n->nfor.var);
                new->nfor.body = copynode(n->nfor.body);
                new->nfor.args = copynode(n->nfor.args);
+               new->nfor.linno = n->nfor.linno;
                break;
        case NCASE:
                new->ncase.cases = copynode(n->ncase.cases);
                new->ncase.expr = copynode(n->ncase.expr);
+               new->ncase.linno = n->ncase.linno;
                break;
        case NCLIST:
                new->nclist.body = copynode(n->nclist.body);
@@ -8653,6 +8851,10 @@ copynode(union node *n)
                new->nclist.next = copynode(n->nclist.next);
                break;
        case NDEFUN:
+               new->ndefun.body = copynode(n->ndefun.body);
+               new->ndefun.text = nodeckstrdup(n->ndefun.text);
+               new->ndefun.linno = n->ndefun.linno;
+               break;
        case NARG:
                new->narg.backquote = copynodelist(n->narg.backquote);
                new->narg.text = nodeckstrdup(n->narg.text);
@@ -8721,7 +8923,7 @@ defun(union node *func)
        INT_OFF;
        entry.cmdtype = CMDFUNCTION;
        entry.u.func = copyfunc(func);
-       addcmdentry(func->narg.text, &entry);
+       addcmdentry(func->ndefun.text, &entry);
        INT_ON;
 }
 
@@ -8731,8 +8933,8 @@ defun(union node *func)
 #define SKIPFUNC       (1 << 2)
 static smallint evalskip;       /* set to SKIPxxx if we are skipping commands */
 static int skipcount;           /* number of levels to skip */
-static int funcnest;            /* depth of function calls */
 static int loopnest;            /* current loop nesting level */
+static int funcline;            /* starting line number of current function, or 0 if not in a function */
 
 /* Forward decl way out to parsing code - dotrap needs it */
 static int evalstring(char *s, int flags);
@@ -8827,6 +9029,9 @@ evaltree(union node *n, int flags)
                status = !evaltree(n->nnot.com, EV_TESTED);
                goto setstatus;
        case NREDIR:
+               errlinno = lineno = n->nredir.linno;
+               if (funcline)
+                       lineno -= funcline - 1;
                expredir(n->nredir.redirect);
                pushredir(n->nredir.redirect);
                status = redirectsafe(n->nredir.redirect, REDIR_PUSH);
@@ -8981,6 +9186,10 @@ evalfor(union node *n, int flags)
        struct stackmark smark;
        int status = 0;
 
+       errlinno = lineno = n->ncase.linno;
+       if (funcline)
+               lineno -= funcline - 1;
+
        setstackmark(&smark);
        arglist.list = NULL;
        arglist.lastp = &arglist.list;
@@ -9012,6 +9221,10 @@ evalcase(union node *n, int flags)
        struct stackmark smark;
        int status = 0;
 
+       errlinno = lineno = n->ncase.linno;
+       if (funcline)
+               lineno -= funcline - 1;
+
        setstackmark(&smark);
        arglist.list = NULL;
        arglist.lastp = &arglist.list;
@@ -9046,6 +9259,10 @@ evalsubshell(union node *n, int flags)
        int backgnd = (n->type == NBACKGND); /* FORK_BG(1) if yes, else FORK_FG(0) */
        int status;
 
+       errlinno = lineno = n->nredir.linno;
+       if (funcline)
+               lineno -= funcline - 1;
+
        expredir(n->nredir.redirect);
        if (!backgnd && (flags & EV_EXIT) && !may_have_traps)
                goto nofork;
@@ -9168,7 +9385,7 @@ evalpipe(union node *n, int flags)
                if (lp->next) {
                        if (pipe(pip) < 0) {
                                close(prevfd);
-                               ash_msg_and_raise_error("pipe call failed");
+                               ash_msg_and_raise_perror("can't create pipe");
                        }
                }
                if (forkshell(jp, lp->n, n->npipe.pipe_backgnd) == 0) {
@@ -9353,8 +9570,10 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
        struct jmploc *volatile savehandler;
        struct jmploc jmploc;
        int e;
+       int savefuncline;
 
        saveparam = shellparam;
+       savefuncline = funcline;
        savehandler = exception_handler;
        e = setjmp(jmploc.loc);
        if (e) {
@@ -9364,7 +9583,7 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
        exception_handler = &jmploc;
        shellparam.malloced = 0;
        func->count++;
-       funcnest++;
+       funcline = func->n.ndefun.linno;
        INT_ON;
        shellparam.nparam = argc - 1;
        shellparam.p = argv + 1;
@@ -9373,11 +9592,11 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
        shellparam.optoff = -1;
 #endif
        pushlocalvars();
-       evaltree(func->n.narg.next, flags & EV_TESTED);
+       evaltree(func->n.ndefun.body, flags & EV_TESTED);
        poplocalvars(0);
  funcdone:
        INT_OFF;
-       funcnest--;
+       funcline = savefuncline;
        freefunc(func);
        freeparam(&shellparam);
        shellparam = saveparam;
@@ -9741,6 +9960,10 @@ evalcommand(union node *cmd, int flags)
        char **nargv;
        smallint cmd_is_exec;
 
+       errlinno = lineno = cmd->ncmd.linno;
+       if (funcline)
+               lineno -= funcline - 1;
+
        /* First expand the arguments. */
        TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags));
        setstackmark(&smark);
@@ -9786,12 +10009,21 @@ evalcommand(union node *cmd, int flags)
        *nargv = NULL;
 
        lastarg = NULL;
-       if (iflag && funcnest == 0 && argc > 0)
+       if (iflag && funcline == 0 && argc > 0)
                lastarg = nargv[-1];
 
        expredir(cmd->ncmd.redirect);
        redir_stop = pushredir(cmd->ncmd.redirect);
        preverrout_fd = 2;
+       if (BASH_XTRACEFD && xflag) {
+               /* NB: bash closes fd == $BASH_XTRACEFD when it is changed.
+                * we do not emulate this. We only use its value.
+                */
+               const char *xtracefd = lookupvar("BASH_XTRACEFD");
+               if (xtracefd && is_number(xtracefd))
+                       preverrout_fd = atoi(xtracefd);
+
+       }
        status = redirectsafe(cmd->ncmd.redirect, REDIR_PUSH | REDIR_SAVEFD2);
 
        path = vpath.var_text;
@@ -9907,7 +10139,9 @@ evalcommand(union node *cmd, int flags)
        switch (cmdentry.cmdtype) {
        default: {
 
-#if ENABLE_FEATURE_SH_NOFORK
+#if ENABLE_FEATURE_SH_STANDALONE \
+ && ENABLE_FEATURE_SH_NOFORK \
+ && NUM_APPLETS > 1
 /* (1) BUG: if variables are set, we need to fork, or save/restore them
  *     around run_nofork_applet() call.
  * (2) Should this check also be done in forkshell()?
@@ -9916,13 +10150,35 @@ evalcommand(union node *cmd, int flags)
                /* find_command() encodes applet_no as (-2 - applet_no) */
                int applet_no = (- cmdentry.u.index - 2);
                if (applet_no >= 0 && APPLET_IS_NOFORK(applet_no)) {
-                       listsetvar(varlist.list, VEXPORT|VSTACK);
-                       /* run <applet>_main() */
+                       char **sv_environ;
+
+                       INT_OFF;
+                       sv_environ = environ;
+                       environ = listvars(VEXPORT, VUNSET, varlist.list, /*end:*/ NULL);
+                       /*
+                        * Run <applet>_main().
+                        * Signals (^C) can't interrupt here.
+                        * Otherwise we can mangle stdio or malloc internal state.
+                        * This makes applets which can run for a long time
+                        * and/or wait for user input ineligible for NOFORK:
+                        * for example, "yes" or "rm" (rm -i waits for input).
+                        */
                        status = run_nofork_applet(applet_no, argv);
+                       environ = sv_environ;
+                       /*
+                        * Try enabling NOFORK for "yes" applet.
+                        * ^C _will_ stop it (write returns EINTR),
+                        * but this causes stdout FILE to be stuck
+                        * and needing clearerr(). What if other applets
+                        * also can get EINTRs? Do we need to switch
+                        * our signals to SA_RESTART?
+                        */
+                       /*clearerr(stdout);*/
+                       INT_ON;
                        break;
                }
 #endif
-               /* Can we avoid forking off? For example, very last command
+               /* Can we avoid forking? For example, very last command
                 * in a script or a subshell does not need forking,
                 * we can just exec it.
                 */
@@ -10441,6 +10697,34 @@ pgetc_eatbnl(void)
        return c;
 }
 
+struct synstack {
+       smalluint syntax;
+       uint8_t innerdq   :1;
+       uint8_t varpushed :1;
+       uint8_t dblquote  :1;
+       int varnest;            /* levels of variables expansion */
+       int dqvarnest;          /* levels of variables expansion within double quotes */
+       int parenlevel;         /* levels of parens in arithmetic */
+       struct synstack *prev;
+       struct synstack *next;
+};
+
+static void
+synstack_push(struct synstack **stack, struct synstack *next, int syntax)
+{
+       memset(next, 0, sizeof(*next));
+       next->syntax = syntax;
+       next->next = *stack;
+       (*stack)->prev = next;
+       *stack = next;
+}
+
+static ALWAYS_INLINE void
+synstack_pop(struct synstack **stack)
+{
+       *stack = (*stack)->next;
+}
+
 /*
  * To handle the "." command, a stack of input files is used.  Pushfile
  * adds a new entry to the stack and popfile restores the previous level.
@@ -10531,17 +10815,18 @@ setinputfile(const char *fname, int flags)
        int fd;
 
        INT_OFF;
-       fd = open(fname, O_RDONLY);
+       fd = open(fname, O_RDONLY | O_CLOEXEC);
        if (fd < 0) {
                if (flags & INPUT_NOFILE_OK)
                        goto out;
                exitstatus = 127;
-               ash_msg_and_raise_error("can't open '%s'", fname);
+               ash_msg_and_raise_perror("can't open '%s'", fname);
        }
        if (fd < 10)
                fd = savefd(fd);
-       else
+       else if (O_CLOEXEC == 0) /* old libc */
                close_on_exec_on(fd);
+
        setinputfd(fd, flags & INPUT_PUSH_FILE);
  out:
        INT_ON;
@@ -10791,7 +11076,7 @@ shiftcmd(int argc UNUSED_PARAM, char **argv)
        if (argv[1])
                n = number(argv[1]);
        if (n > shellparam.nparam)
-               n = 0; /* bash compat, was = shellparam.nparam; */
+               return 1;
        INT_OFF;
        shellparam.nparam -= n;
        for (ap1 = shellparam.p; --n >= 0; ap1++) {
@@ -10822,7 +11107,7 @@ showvars(const char *sep_prefix, int on, int off)
        const char *sep;
        char **ep, **epend;
 
-       ep = listvars(on, off, &epend);
+       ep = listvars(on, off, /*strlist:*/ NULL, &epend);
        qsort(ep, epend - ep, sizeof(char *), vpcmp);
 
        sep = *sep_prefix ? " " : sep_prefix;
@@ -10831,9 +11116,17 @@ showvars(const char *sep_prefix, int on, int off)
                const char *p;
                const char *q;
 
-               p = strchrnul(*ep, '=');
+               p = endofname(*ep);
+/* Used to have simple "p = strchrnul(*ep, '=')" here instead, but this
+ * makes "export -p" to have output not suitable for "eval":
+ * import os
+ * os.environ["test-test"]="test"
+ * if os.fork() == 0:
+ *   os.execv("ash", [ 'ash', '-c', 'eval $(export -p); echo OK' ])  # fixes this
+ * os.execv("ash", [ 'ash', '-c', 'env | grep test-test' ])
+ */
                q = nullstr;
-               if (*p)
+               if (*p == '=')
                        q = single_quote(++p);
                out1fmt("%s%s%.*s%s\n", sep_prefix, sep, (int)(p - *ep), *ep, q);
        }
@@ -10909,6 +11202,7 @@ getopts(char *optstr, char *optvar, char **optfirst)
                p = *optnext;
                if (p == NULL || *p != '-' || *++p == '\0') {
  atend:
+                       unsetvar("OPTARG");
                        p = NULL;
                        done = 1;
                        goto out;
@@ -10921,7 +11215,11 @@ getopts(char *optstr, char *optvar, char **optfirst)
        c = *p++;
        for (q = optstr; *q != c;) {
                if (*q == '\0') {
-                       if (optstr[0] == ':') {
+                       /* OPTERR is a bashism */
+                       const char *cp = lookupvar("OPTERR");
+                       if ((cp && LONE_CHAR(cp, '0'))
+                        || (optstr[0] == ':')
+                       ) {
                                sbuf[0] = c;
                                /*sbuf[1] = '\0'; - already is */
                                setvar0("OPTARG", sbuf);
@@ -10938,7 +11236,11 @@ getopts(char *optstr, char *optvar, char **optfirst)
 
        if (*++q == ':') {
                if (*p == '\0' && (p = *optnext) == NULL) {
-                       if (optstr[0] == ':') {
+                       /* OPTERR is a bashism */
+                       const char *cp = lookupvar("OPTERR");
+                       if ((cp && LONE_CHAR(cp, '0'))
+                        || (optstr[0] == ':')
+                       ) {
                                sbuf[0] = c;
                                /*sbuf[1] = '\0'; - already is */
                                setvar0("OPTARG", sbuf);
@@ -11244,7 +11546,7 @@ parsefname(void)
                if (quoteflag == 0)
                        n->type = NXHERE;
                TRACE(("Here document %d\n", n->type));
-               rmescapes(wordtext, 0);
+               rmescapes(wordtext, 0, NULL);
                here->eofmark = wordtext;
                here->next = NULL;
                if (heredoclist == NULL)
@@ -11269,6 +11571,7 @@ simplecmd(void)
        union node *vars, **vpp;
        union node **rpp, *redir;
        int savecheckkwd;
+       int savelinno;
 #if BASH_TEST2
        smallint double_brackets_flag = 0;
 #endif
@@ -11282,6 +11585,7 @@ simplecmd(void)
        rpp = &redir;
 
        savecheckkwd = CHKALIAS;
+       savelinno = g_parsefile->linno;
        for (;;) {
                int t;
                checkkwd = savecheckkwd;
@@ -11337,10 +11641,12 @@ simplecmd(void)
                                case TLP:
                                        function_flag = 0;
                                        break;
+# if BASH_TEST2
                                case TWORD:
                                        if (strcmp("[[", wordtext) == 0)
                                                goto do_func;
                                        /* fall through */
+# endif
                                default:
                                        raise_error_unexpected_syntax(-1);
                                }
@@ -11371,7 +11677,9 @@ simplecmd(void)
                                }
                                n->type = NDEFUN;
                                checkkwd = CHKNL | CHKKWD | CHKALIAS;
-                               n->narg.next = parse_command();
+                               n->ndefun.text = n->narg.text;
+                               n->ndefun.linno = g_parsefile->linno;
+                               n->ndefun.body = parse_command();
                                return n;
                        }
                        IF_BASH_FUNCTION(function_flag = 0;)
@@ -11386,7 +11694,9 @@ simplecmd(void)
        *vpp = NULL;
        *rpp = NULL;
        n = stzalloc(sizeof(struct ncmd));
-       n->type = NCMD;
+       if (NCMD != 0)
+               n->type = NCMD;
+       n->ncmd.linno = savelinno;
        n->ncmd.args = args;
        n->ncmd.assign = vars;
        n->ncmd.redirect = redir;
@@ -11402,10 +11712,13 @@ parse_command(void)
        union node *redir, **rpp;
        union node **rpp2;
        int t;
+       int savelinno;
 
        redir = NULL;
        rpp2 = &redir;
 
+       savelinno = g_parsefile->linno;
+
        switch (readtoken()) {
        default:
                raise_error_unexpected_syntax(-1);
@@ -11456,6 +11769,7 @@ parse_command(void)
                        raise_error_syntax("bad for loop variable");
                n1 = stzalloc(sizeof(struct nfor));
                n1->type = NFOR;
+               n1->nfor.linno = savelinno;
                n1->nfor.var = wordtext;
                checkkwd = CHKNL | CHKKWD | CHKALIAS;
                if (readtoken() == TIN) {
@@ -11496,6 +11810,7 @@ parse_command(void)
        case TCASE:
                n1 = stzalloc(sizeof(struct ncase));
                n1->type = NCASE;
+               n1->ncase.linno = savelinno;
                if (readtoken() != TWORD)
                        raise_error_unexpected_syntax(TWORD);
                n1->ncase.expr = n2 = stzalloc(sizeof(struct narg));
@@ -11547,6 +11862,7 @@ parse_command(void)
        case TLP:
                n1 = stzalloc(sizeof(struct nredir));
                n1->type = NSUBSHELL;
+               n1->nredir.linno = savelinno;
                n1->nredir.n = list(0);
                /*n1->nredir.redirect = NULL; - stzalloc did it */
                t = TRP;
@@ -11580,6 +11896,7 @@ parse_command(void)
                if (n1->type != NSUBSHELL) {
                        n2 = stzalloc(sizeof(struct nredir));
                        n2->type = NREDIR;
+                       n2->nredir.linno = savelinno;
                        n2->nredir.n = n1;
                        n1 = n2;
                }
@@ -11670,21 +11987,13 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
        size_t len;
        struct nodelist *bqlist;
        smallint quotef;
-       smallint dblquote;
        smallint oldstyle;
-       IF_FEATURE_SH_MATH(smallint prevsyntax;) /* syntax before arithmetic */
        smallint pssyntax;   /* we are expanding a prompt string */
-       int varnest;         /* levels of variables expansion */
-       IF_FEATURE_SH_MATH(int arinest;)    /* levels of arithmetic expansion */
-       IF_FEATURE_SH_MATH(int parenlevel;) /* levels of parens in arithmetic */
-       int dqvarnest;       /* levels of variables expansion within double quotes */
-
        IF_BASH_DOLLAR_SQUOTE(smallint bash_dollar_squote = 0;)
+       /* syntax stack */
+       struct synstack synbase = { };
+       struct synstack *synstack = &synbase;
 
-       startlinno = g_parsefile->linno;
-       bqlist = NULL;
-       quotef = 0;
-       IF_FEATURE_SH_MATH(prevsyntax = 0;)
 #if ENABLE_ASH_EXPAND_PRMT
        pssyntax = (syntax == PSSYNTAX);
        if (pssyntax)
@@ -11692,11 +12001,12 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
 #else
        pssyntax = 0; /* constant */
 #endif
-       dblquote = (syntax == DQSYNTAX);
-       varnest = 0;
-       IF_FEATURE_SH_MATH(arinest = 0;)
-       IF_FEATURE_SH_MATH(parenlevel = 0;)
-       dqvarnest = 0;
+       synstack->syntax = syntax;
+
+       if (syntax == DQSYNTAX)
+               synstack->dblquote = 1;
+       quotef = 0;
+       bqlist = NULL;
 
        STARTSTACKSTR(out);
  loop:
@@ -11704,10 +12014,13 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
        CHECKEND();     /* set c to PEOF if at end of here document */
        for (;;) {      /* until end of line or end of word */
                CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
-               switch (SIT(c, syntax)) {
+               switch (SIT(c, synstack->syntax)) {
                case CNL:       /* '\n' */
-                       if (syntax == BASESYNTAX)
+                       if (synstack->syntax == BASESYNTAX
+                        && !synstack->varnest
+                       ) {
                                goto endword;   /* exit outer loop */
+                       }
                        USTPUTC(c, out);
                        nlprompt();
                        c = pgetc();
@@ -11726,13 +12039,13 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
                                if (c & 0x100) {
                                        /* Unknown escape. Encode as '\z' */
                                        c = (unsigned char)c;
-                                       if (eofmark == NULL || dblquote)
+                                       if (eofmark == NULL || synstack->dblquote)
                                                USTPUTC(CTLESC, out);
                                        USTPUTC('\\', out);
                                }
                        }
 #endif
-                       if (eofmark == NULL || dblquote)
+                       if (!eofmark || synstack->dblquote || synstack->varnest)
                                USTPUTC(CTLESC, out);
                        USTPUTC(c, out);
                        break;
@@ -11749,13 +12062,17 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
                                        USTPUTC(CTLESC, out);
                                        USTPUTC('\\', out);
                                }
-                               /* Backslash is retained if we are in "str" and next char isn't special */
-                               if (dblquote
+                               /* Backslash is retained if we are in "str"
+                                * and next char isn't dquote-special.
+                                */
+                               if (synstack->dblquote
                                 && c != '\\'
                                 && c != '`'
                                 && c != '$'
-                                && (c != '"' || eofmark != NULL)
+                                && (c != '"' || (eofmark != NULL && !synstack->varnest))
+                                && (c != '}' || !synstack->varnest)
                                ) {
+                                       USTPUTC(CTLESC, out); /* protect '\' from glob */
                                        USTPUTC('\\', out);
                                }
                                USTPUTC(CTLESC, out);
@@ -11764,56 +12081,62 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
                        }
                        break;
                case CSQUOTE:
-                       syntax = SQSYNTAX;
+                       synstack->syntax = SQSYNTAX;
  quotemark:
                        if (eofmark == NULL) {
                                USTPUTC(CTLQUOTEMARK, out);
                        }
                        break;
                case CDQUOTE:
-                       syntax = DQSYNTAX;
-                       dblquote = 1;
+                       synstack->syntax = DQSYNTAX;
+                       synstack->dblquote = 1;
+ toggledq:
+                       if (synstack->varnest)
+                               synstack->innerdq ^= 1;
                        goto quotemark;
                case CENDQUOTE:
                        IF_BASH_DOLLAR_SQUOTE(bash_dollar_squote = 0;)
-                       if (eofmark != NULL && varnest == 0) {
+                       if (eofmark != NULL && synstack->varnest == 0) {
                                USTPUTC(c, out);
-                       } else {
-                               if (dqvarnest == 0) {
-                                       syntax = BASESYNTAX;
-                                       dblquote = 0;
-                               }
-                               quotef = 1;
-                               goto quotemark;
+                               break;
                        }
-                       break;
+
+                       if (synstack->dqvarnest == 0) {
+                               synstack->syntax = BASESYNTAX;
+                               synstack->dblquote = 0;
+                       }
+
+                       quotef = 1;
+
+                       if (c == '"')
+                               goto toggledq;
+
+                       goto quotemark;
                case CVAR:      /* '$' */
                        PARSESUB();             /* parse substitution */
                        break;
                case CENDVAR:   /* '}' */
-                       if (varnest > 0) {
-                               varnest--;
-                               if (dqvarnest > 0) {
-                                       dqvarnest--;
-                               }
+                       if (!synstack->innerdq && synstack->varnest > 0) {
+                               if (!--synstack->varnest && synstack->varpushed)
+                                       synstack_pop(&synstack);
+                               else if (synstack->dqvarnest > 0)
+                                       synstack->dqvarnest--;
                                c = CTLENDVAR;
                        }
                        USTPUTC(c, out);
                        break;
 #if ENABLE_FEATURE_SH_MATH
                case CLP:       /* '(' in arithmetic */
-                       parenlevel++;
+                       synstack->parenlevel++;
                        USTPUTC(c, out);
                        break;
                case CRP:       /* ')' in arithmetic */
-                       if (parenlevel > 0) {
-                               parenlevel--;
+                       if (synstack->parenlevel > 0) {
+                               synstack->parenlevel--;
                        } else {
                                if (pgetc_eatbnl() == ')') {
                                        c = CTLENDARI;
-                                       if (--arinest == 0) {
-                                               syntax = prevsyntax;
-                                       }
+                                       synstack_pop(&synstack);
                                } else {
                                        /*
                                         * unbalanced parens
@@ -11826,6 +12149,12 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
                        break;
 #endif
                case CBQUOTE:   /* '`' */
+                       if (checkkwd & CHKEOFMARK) {
+                               quotef = 1;
+                               USTPUTC('`', out);
+                               break;
+                       }
+
                        PARSEBACKQOLD();
                        break;
                case CENDFILE:
@@ -11833,7 +12162,7 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
                case CIGN:
                        break;
                default:
-                       if (varnest == 0) {
+                       if (synstack->varnest == 0) {
 #if BASH_REDIR_OUTPUT
                                if (c == '&') {
 //Can't call pgetc_eatbnl() here, this requires three-deep pungetc()
@@ -11852,13 +12181,12 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
  endword:
 
 #if ENABLE_FEATURE_SH_MATH
-       if (syntax == ARISYNTAX)
+       if (synstack->syntax == ARISYNTAX)
                raise_error_syntax("missing '))'");
 #endif
-       if (syntax != BASESYNTAX && eofmark == NULL)
+       if (synstack->syntax != BASESYNTAX && eofmark == NULL)
                raise_error_syntax("unterminated quoted string");
-       if (varnest != 0) {
-               startlinno = g_parsefile->linno;
+       if (synstack->varnest != 0) {
                /* { */
                raise_error_syntax("missing '}'");
        }
@@ -11959,7 +12287,7 @@ parseredir: {
        np = stzalloc(sizeof(struct nfile));
        if (c == '>') {
                np->nfile.fd = 1;
-               c = pgetc();
+               c = pgetc_eatbnl();
                if (c == '>')
                        np->type = NAPPEND;
                else if (c == '|')
@@ -11981,7 +12309,7 @@ parseredir: {
 #endif
        else { /* c == '<' */
                /*np->nfile.fd = 0; - stzalloc did it */
-               c = pgetc();
+               c = pgetc_eatbnl();
                switch (c) {
                case '<':
                        if (sizeof(struct nfile) != sizeof(struct nhere)) {
@@ -11991,7 +12319,7 @@ parseredir: {
                        np->type = NHERE;
                        heredoc = stzalloc(sizeof(struct heredoc));
                        heredoc->here = np;
-                       c = pgetc();
+                       c = pgetc_eatbnl();
                        if (c == '-') {
                                heredoc->striptabs = 1;
                        } else {
@@ -12040,7 +12368,7 @@ parsesub: {
         || (c != '(' && c != '{' && !is_name(c) && !is_special(c))
        ) {
 #if BASH_DOLLAR_SQUOTE
-               if (syntax != DQSYNTAX && c == '\'')
+               if (synstack->syntax != DQSYNTAX && c == '\'')
                        bash_dollar_squote = 1;
                else
 #endif
@@ -12060,6 +12388,8 @@ parsesub: {
                }
        } else {
                /* $VAR, $<specialchar>, ${...}, or PEOA/PEOF */
+               smalluint newsyn = synstack->syntax;
+
                USTPUTC(CTLVAR, out);
                typeloc = out - (char *)stackblock();
                STADJUST(1, out);
@@ -12081,7 +12411,7 @@ parsesub: {
                                STPUTC(c, out);
                                c = pgetc_eatbnl();
                        } while (isdigit(c));
-               } else if (is_special(c)) {
+               } else {
                        /* $[{[#]]<specialchar>[}] */
                        int cc = c;
 
@@ -12099,10 +12429,16 @@ parsesub: {
                                        cc = '#';
                                }
                        }
+
+                       if (!is_special(cc)) {
+                               if (subtype == VSLENGTH)
+                                       subtype = 0;
+                               goto badsub;
+                       }
+
                        USTPUTC(cc, out);
-               } else {
-                       goto badsub;
                }
+
                if (c != '}' && subtype == VSLENGTH) {
                        /* ${#VAR didn't end with } */
                        goto badsub;
@@ -12112,6 +12448,8 @@ parsesub: {
                        static const char types[] ALIGN1 = "}-+?=";
                        /* ${VAR...} but not $VAR or ${#VAR} */
                        /* c == first char after VAR */
+                       int cc = c;
+
                        switch (c) {
                        case ':':
                                c = pgetc_eatbnl();
@@ -12136,21 +12474,24 @@ parsesub: {
                                break;
                        }
                        case '%':
-                       case '#': {
-                               int cc = c;
+                       case '#':
                                subtype = (c == '#' ? VSTRIMLEFT : VSTRIMRIGHT);
                                c = pgetc_eatbnl();
-                               if (c != cc)
-                                       goto badsub;
-                               subtype++;
+                               if (c == cc)
+                                       subtype++;
+                               else
+                                       pungetc();
+
+                               newsyn = BASESYNTAX;
                                break;
-                       }
 #if BASH_PATTERN_SUBST
                        case '/':
                                /* ${v/[/]pattern/repl} */
 //TODO: encode pattern and repl separately.
-// Currently ${v/$var_with_slash/repl} is horribly broken
+// Currently cases like: v=1;echo ${v/$((1/1))/ONE}
+// are broken (should print "ONE")
                                subtype = VSREPLACE;
+                               newsyn = BASESYNTAX;
                                c = pgetc_eatbnl();
                                if (c != '/')
                                        goto badsub;
@@ -12162,11 +12503,26 @@ parsesub: {
  badsub:
                        pungetc();
                }
+
+               if (newsyn == ARISYNTAX)
+                       newsyn = DQSYNTAX;
+
+               if ((newsyn != synstack->syntax || synstack->innerdq)
+                && subtype != VSNORMAL
+               ) {
+                       synstack_push(&synstack,
+                               synstack->prev ?: alloca(sizeof(*synstack)),
+                               newsyn);
+
+                       synstack->varpushed = 1;
+                       synstack->dblquote = newsyn != BASESYNTAX;
+               }
+
                ((unsigned char *)stackblock())[typeloc] = subtype;
                if (subtype != VSNORMAL) {
-                       varnest++;
-                       if (dblquote)
-                               dqvarnest++;
+                       synstack->varnest++;
+                       if (synstack->dblquote)
+                               synstack->dqvarnest++;
                }
                STPUTC('=', out);
        }
@@ -12215,25 +12571,15 @@ parsebackq: {
                        int pc;
 
                        setprompt_if(needprompt, 2);
-                       pc = pgetc();
+                       pc = pgetc_eatbnl();
                        switch (pc) {
                        case '`':
                                goto done;
 
                        case '\\':
-                               pc = pgetc();
-                               if (pc == '\n') {
-                                       nlprompt();
-                                       /*
-                                        * If eating a newline, avoid putting
-                                        * the newline into the new character
-                                        * stream (via the STPUTC after the
-                                        * switch).
-                                        */
-                                       continue;
-                               }
+                               pc = pgetc(); /* or pgetc_eatbnl()? why (example)? */
                                if (pc != '\\' && pc != '`' && pc != '$'
-                                && (!dblquote || pc != '"')
+                                && (!synstack->dblquote || pc != '"')
                                ) {
                                        STPUTC('\\', pout);
                                }
@@ -12244,7 +12590,6 @@ parsebackq: {
 
                        case PEOF:
                        IF_ASH_ALIAS(case PEOA:)
-                               startlinno = g_parsefile->linno;
                                raise_error_syntax("EOF in backquote substitution");
 
                        case '\n':
@@ -12309,10 +12654,11 @@ parsebackq: {
  * Parse an arithmetic expansion (indicate start of one and set state)
  */
 parsearith: {
-       if (++arinest == 1) {
-               prevsyntax = syntax;
-               syntax = ARISYNTAX;
-       }
+
+       synstack_push(&synstack,
+                       synstack->prev ?: alloca(sizeof(*synstack)),
+                       ARISYNTAX);
+       synstack->dblquote = 1;
        USTPUTC(CTLARI, out);
        goto parsearith_return;
 }
@@ -12326,8 +12672,6 @@ parsearith: {
  *      quoted.
  * If the token is TREDIR, then we set redirnode to a structure containing
  *      the redirection.
- * In all cases, the variable startlinno is set to the number of the line
- *      on which the token starts.
  *
  * [Change comment:  here documents and internal procedures]
  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
@@ -12365,9 +12709,8 @@ xxreadtoken(void)
                return lasttoken;
        }
        setprompt_if(needprompt, 2);
-       startlinno = g_parsefile->linno;
        for (;;) {                      /* until token or start of word found */
-               c = pgetc();
+               c = pgetc_eatbnl();
                if (c == ' ' || c == '\t' IF_ASH_ALIAS( || c == PEOA))
                        continue;
 
@@ -12376,11 +12719,7 @@ xxreadtoken(void)
                                continue;
                        pungetc();
                } else if (c == '\\') {
-                       if (pgetc() != '\n') {
-                               pungetc();
-                               break; /* return readtoken1(...) */
-                       }
-                       nlprompt();
+                       break; /* return readtoken1(...) */
                } else {
                        const char *p;
 
@@ -12395,7 +12734,7 @@ xxreadtoken(void)
                                        break; /* return readtoken1(...) */
 
                                if ((int)(p - xxreadtoken_chars) >= xxreadtoken_singles) {
-                                       int cc = pgetc();
+                                       int cc = pgetc_eatbnl();
                                        if (cc == c) {    /* double occurrence? */
                                                p += xxreadtoken_doubles + 1;
                                        } else {
@@ -12426,9 +12765,8 @@ xxreadtoken(void)
                return lasttoken;
        }
        setprompt_if(needprompt, 2);
-       startlinno = g_parsefile->linno;
        for (;;) {      /* until token or start of word found */
-               c = pgetc();
+               c = pgetc_eatbnl();
                switch (c) {
                case ' ': case '\t':
                IF_ASH_ALIAS(case PEOA:)
@@ -12438,30 +12776,23 @@ xxreadtoken(void)
                                continue;
                        pungetc();
                        continue;
-               case '\\':
-                       if (pgetc() == '\n') {
-                               nlprompt();
-                               continue;
-                       }
-                       pungetc();
-                       goto breakloop;
                case '\n':
                        nlnoprompt();
                        RETURN(TNL);
                case PEOF:
                        RETURN(TEOF);
                case '&':
-                       if (pgetc() == '&')
+                       if (pgetc_eatbnl() == '&')
                                RETURN(TAND);
                        pungetc();
                        RETURN(TBACKGND);
                case '|':
-                       if (pgetc() == '|')
+                       if (pgetc_eatbnl() == '|')
                                RETURN(TOR);
                        pungetc();
                        RETURN(TPIPE);
                case ';':
-                       if (pgetc() == ';')
+                       if (pgetc_eatbnl() == ';')
                                RETURN(TENDCASE);
                        pungetc();
                        RETURN(TSEMI);
@@ -12469,11 +12800,9 @@ xxreadtoken(void)
                        RETURN(TLP);
                case ')':
                        RETURN(TRP);
-               default:
-                       goto breakloop;
                }
+               break;
        }
- breakloop:
        return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
 #undef RETURN
 }
@@ -12609,7 +12938,24 @@ expandstr(const char *ps, int syntax_type)
 
        saveprompt = doprompt;
        doprompt = 0;
-       readtoken1(pgetc(), syntax_type, FAKEEOFMARK, 0);
+
+       /* readtoken1() might die horribly.
+        * Try a prompt with syntactically wrong command:
+        * PS1='$(date "+%H:%M:%S) > '
+        */
+       {
+               volatile int saveint;
+               struct jmploc *volatile savehandler = exception_handler;
+               struct jmploc jmploc;
+               SAVE_INT(saveint);
+               if (setjmp(jmploc.loc) == 0) {
+                       exception_handler = &jmploc;
+                       readtoken1(pgetc(), syntax_type, FAKEEOFMARK, 0);
+               }
+               exception_handler = savehandler;
+               RESTORE_INT(saveint);
+       }
+
        doprompt = saveprompt;
 
        popfile();
@@ -12678,7 +13024,7 @@ evalstring(char *s, int flags)
 
        exception_handler = savehandler;
        if (ex)
-                longjmp(exception_handler->loc, ex);
+               longjmp(exception_handler->loc, ex);
 
        return status;
 }
@@ -12801,10 +13147,14 @@ find_dot_file(char *name)
                if (fullname != name)
                        stunalloc(fullname);
        }
+       /* not found in PATH */
 
-       /* not found in the PATH */
+#if ENABLE_ASH_BASH_SOURCE_CURDIR
+       return name;
+#else
        ash_msg_and_raise_error("%s: not found", name);
        /* NOTREACHED */
+#endif
 }
 
 static int FAST_FUNC
@@ -13059,8 +13409,21 @@ find_command(char *name, struct cmdentry *entry, int act, const char *path)
        /* We failed.  If there was an entry for this command, delete it */
        if (cmdp && updatetbl)
                delete_cmd_entry();
-       if (act & DO_ERR)
+       if (act & DO_ERR) {
+#if ENABLE_ASH_BASH_NOT_FOUND_HOOK
+               struct tblentry *hookp = cmdlookup("command_not_found_handle", 0);
+               if (hookp && hookp->cmdtype == CMDFUNCTION) {
+                       char *argv[3];
+                       argv[0] = (char*) "command_not_found_handle";
+                       argv[1] = name;
+                       argv[2] = NULL;
+                       evalfun(hookp->param.func, 2, argv, 0);
+                       entry->cmdtype = CMDUNKNOWN;
+                       return;
+               }
+#endif
                ash_msg("%s: %s", name, errmsg(e, "not found"));
+       }
        entry->cmdtype = CMDUNKNOWN;
        return;
 
@@ -13315,21 +13678,23 @@ static const unsigned char timescmd_str[] ALIGN1 = {
 static int FAST_FUNC
 timescmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 {
-       unsigned long clk_tck, s, t;
+       unsigned clk_tck;
        const unsigned char *p;
        struct tms buf;
 
        clk_tck = bb_clk_tck();
-       times(&buf);
 
+       times(&buf);
        p = timescmd_str;
        do {
+               unsigned sec, frac;
+               unsigned long t;
                t = *(clock_t *)(((char *) &buf) + p[1]);
-               s = t / clk_tck;
-               t = t % clk_tck;
-               out1fmt("%lum%lu.%03lus%c",
-                       s / 60, s % 60,
-                       (t * 1000) / clk_tck,
+               sec = t / clk_tck;
+               frac = t % clk_tck;
+               out1fmt("%um%u.%03us%c",
+                       sec / 60, sec % 60,
+                       (frac * 1000) / clk_tck,
                        p[0]);
                p += 2;
        } while (*p);
@@ -13368,10 +13733,10 @@ letcmd(int argc UNUSED_PARAM, char **argv)
  *      -p PROMPT       Display PROMPT on stderr (if input is from tty)
  *      -t SECONDS      Timeout after SECONDS (tty or pipe only)
  *      -u FD           Read from given FD instead of fd 0
+ *      -d DELIM        End on DELIM char, not newline
  * This uses unbuffered input, which may be avoidable in some cases.
  * TODO: bash also has:
  *      -a ARRAY        Read into array[0],[1],etc
- *      -d DELIM        End on DELIM char, not newline
  *      -e              Use line editing (tty only)
  */
 static int FAST_FUNC
@@ -13381,11 +13746,12 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
        char *opt_p = NULL;
        char *opt_t = NULL;
        char *opt_u = NULL;
+       char *opt_d = NULL; /* optimized out if !BASH */
        int read_flags = 0;
        const char *r;
        int i;
 
-       while ((i = nextopt("p:u:rt:n:s")) != '\0') {
+       while ((i = nextopt("p:u:rt:n:sd:")) != '\0') {
                switch (i) {
                case 'p':
                        opt_p = optionarg;
@@ -13405,6 +13771,11 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
                case 'u':
                        opt_u = optionarg;
                        break;
+#if BASH_READ_D
+               case 'd':
+                       opt_d = optionarg;
+                       break;
+#endif
                default:
                        break;
                }
@@ -13422,12 +13793,15 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
                opt_n,
                opt_p,
                opt_t,
-               opt_u
+               opt_u,
+               opt_d
        );
        INT_ON;
 
        if ((uintptr_t)r == 1 && errno == EINTR) {
-               /* to get SIGCHLD: sleep 1 & read x; echo $x */
+               /* To get SIGCHLD: sleep 1 & read x; echo $x
+                * Correct behavior is to not exit "read"
+                */
                if (pending_sig == 0)
                        goto again;
        }
@@ -13481,8 +13855,8 @@ umaskcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
                }
        } else {
                char *modestr = *argptr;
-                /* numeric umasks are taken as-is */
-                /* symbolic umasks are inverted: "umask a=rx" calls umask(222) */
+               /* numeric umasks are taken as-is */
+               /* symbolic umasks are inverted: "umask a=rx" calls umask(222) */
                if (!isdigit(modestr[0]))
                        mask ^= 0777;
                mask = bb_parse_mode(modestr, mask);
@@ -13542,13 +13916,15 @@ exitshell(void)
        /* NOTREACHED */
 }
 
-static void
+/* Don't inline: conserve stack of caller from having our locals too */
+static NOINLINE void
 init(void)
 {
        /* we will never free this */
        basepf.next_to_pgetc = basepf.buf = ckmalloc(IBUFSIZ);
+       basepf.linno = 1;
 
-       sigmode[SIGCHLD - 1] = S_DFL;
+       sigmode[SIGCHLD - 1] = S_DFL; /* ensure we install handler even if it is SIG_IGNed */
        setsignal(SIGCHLD);
 
        /* bash re-enables SIGHUP which is SIG_IGNed on entry.
@@ -13559,12 +13935,21 @@ init(void)
        {
                char **envp;
                const char *p;
-               struct stat st1, st2;
 
                initvar();
                for (envp = environ; envp && *envp; envp++) {
-                       p = endofname(*envp);
-                       if (p != *envp && *p == '=') {
+/* Used to have
+ *                     p = endofname(*envp);
+ *                     if (p != *envp && *p == '=') {
+ * here to weed out badly-named variables, but this breaks
+ * scenarios where people do want them passed to children:
+ * import os
+ * os.environ["test-test"]="test"
+ * if os.fork() == 0:
+ *   os.execv("ash", [ 'ash', '-c', 'eval $(export -p); echo OK' ])  # fixes this
+ * os.execv("ash", [ 'ash', '-c', 'env | grep test-test' ])  # breaks this
+ */
+                       if (strchr(*envp, '=')) {
                                setvareq(*envp, VEXPORT|VTEXTFIXED);
                        }
                }
@@ -13585,6 +13970,7 @@ init(void)
 #endif
                p = lookupvar("PWD");
                if (p) {
+                       struct stat st1, st2;
                        if (p[0] != '/' || stat(p, &st1) || stat(".", &st2)
                         || st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino
                        ) {
@@ -13597,7 +13983,7 @@ init(void)
 
 
 //usage:#define ash_trivial_usage
-//usage:       "[-/+OPTIONS] [-/+o OPT]... [-c 'SCRIPT' [ARG0 [ARGS]] / FILE [ARGS]]"
+//usage:       "[-/+OPTIONS] [-/+o OPT]... [-c 'SCRIPT' [ARG0 [ARGS]] / FILE [ARGS] / -s [ARGS]]"
 //usage:#define ash_full_usage "\n\n"
 //usage:       "Unix shell interpreter"