tls: code shrink
[oweals/busybox.git] / shell / shell_common.c
index f02ed81eac07d2482e421bca9f3357eae1cc8ed3..f2bf5ab65457c2145825f104e2c51ced41dcf4c9 100644 (file)
@@ -20,6 +20,7 @@
 #include "shell_common.h"
 
 const char defifsvar[] ALIGN1 = "IFS= \t\n";
+const char defoptindvar[] ALIGN1 = "OPTIND=1";
 
 
 int FAST_FUNC is_well_formed_var_name(const char *s, char terminator)
@@ -36,32 +37,37 @@ int FAST_FUNC is_well_formed_var_name(const char *s, char terminator)
 
 /* read builtin */
 
+/* Needs to be interruptible: shell must handle traps and shell-special signals
+ * while inside read. To implement this, be sure to not loop on EINTR
+ * and return errno == EINTR reliably.
+ */
 //TODO: use more efficient setvar() which takes a pointer to malloced "VAR=VAL"
 //string. hush naturally has it, and ash has setvareq().
 //Here we can simply store "VAR=" at buffer start and store read data directly
 //after "=", then pass buffer to setvar() to consume.
 const char* FAST_FUNC
-shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
-       char       **argv,
-       const char *ifs,
-       int        read_flags,
-       const char *opt_n,
-       const char *opt_p,
-       const char *opt_t,
-       const char *opt_u
-)
+shell_builtin_read(struct builtin_read_params *params)
 {
+       struct pollfd pfd[1];
+#define fd (pfd[0].fd) /* -u FD */
+       unsigned err;
        unsigned end_ms; /* -t TIMEOUT */
-       int fd; /* -u FD */
        int nchars; /* -n NUM */
        char **pp;
        char *buffer;
+       char delim;
        struct termios tty, old_tty;
        const char *retval;
        int bufpos; /* need to be able to hold -1 */
        int startword;
        smallint backslash;
+       char **argv;
+       const char *ifs;
+       int read_flags;
+
+       errno = err = 0;
 
+       argv = params->argv;
        pp = argv;
        while (*pp) {
                if (!is_well_formed_var_name(*pp, '\0')) {
@@ -73,65 +79,91 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
        }
 
        nchars = 0; /* if != 0, -n is in effect */
-       if (opt_n) {
-               nchars = bb_strtou(opt_n, NULL, 10);
+       if (params->opt_n) {
+               nchars = bb_strtou(params->opt_n, NULL, 10);
                if (nchars < 0 || errno)
                        return "invalid count";
                /* note: "-n 0": off (bash 3.2 does this too) */
        }
+
        end_ms = 0;
-       if (opt_t) {
-               end_ms = bb_strtou(opt_t, NULL, 10);
-               if (errno || end_ms > UINT_MAX / 2048)
+       if (params->opt_t && !ENABLE_FEATURE_SH_READ_FRAC) {
+               end_ms = bb_strtou(params->opt_t, NULL, 10);
+               if (errno)
                        return "invalid timeout";
+               if (end_ms > UINT_MAX / 2048) /* be safely away from overflow */
+                       end_ms = UINT_MAX / 2048;
                end_ms *= 1000;
-#if 0 /* even bash has no -t N.NNN support */
-               ts.tv_sec = bb_strtou(opt_t, &p, 10);
-               ts.tv_usec = 0;
-               /* EINVAL means number is ok, but not terminated by NUL */
-               if (*p == '.' && errno == EINVAL) {
-                       char *p2;
-                       if (*++p) {
-                               int scale;
-                               ts.tv_usec = bb_strtou(p, &p2, 10);
-                               if (errno)
-                                       return "invalid timeout";
-                               scale = p2 - p;
-                               /* normalize to usec */
-                               if (scale > 6)
+       }
+       if (params->opt_t && ENABLE_FEATURE_SH_READ_FRAC) {
+               /* bash 4.3 (maybe earlier) supports -t N.NNNNNN */
+               char *p;
+               /* Eat up to three fractional digits */
+               int frac_digits = 3 + 1;
+
+               end_ms = bb_strtou(params->opt_t, &p, 10);
+               if (end_ms > UINT_MAX / 2048) /* be safely away from overflow */
+                       end_ms = UINT_MAX / 2048;
+
+               if (errno) {
+                       /* EINVAL = number is ok, but not NUL terminated */
+                       if (errno != EINVAL || *p != '.')
+                               return "invalid timeout";
+                       /* Do not check the rest: bash allows "0.123456xyz" */
+                       while (*++p && --frac_digits) {
+                               end_ms *= 10;
+                               end_ms += (*p - '0');
+                               if ((unsigned char)(*p - '0') > 9)
                                        return "invalid timeout";
-                               while (scale++ < 6)
-                                       ts.tv_usec *= 10;
                        }
-               } else if (ts.tv_sec < 0 || errno) {
-                       return "invalid timeout";
                }
-               if (!(ts.tv_sec | ts.tv_usec)) { /* both are 0? */
-                       return "invalid timeout";
+               while (--frac_digits > 0) {
+                       end_ms *= 10;
                }
-#endif /* if 0 */
        }
+
        fd = STDIN_FILENO;
-       if (opt_u) {
-               fd = bb_strtou(opt_u, NULL, 10);
+       if (params->opt_u) {
+               fd = bb_strtou(params->opt_u, NULL, 10);
                if (fd < 0 || errno)
                        return "invalid file descriptor";
        }
 
-       if (opt_p && isatty(fd)) {
-               fputs(opt_p, stderr);
+       if (params->opt_t && end_ms == 0) {
+               /* "If timeout is 0, read returns immediately, without trying
+                * to read any data. The exit status is 0 if input is available
+                * on the specified file descriptor, non-zero otherwise."
+                * bash seems to ignore -p PROMPT for this use case.
+                */
+               int r;
+               pfd[0].events = POLLIN;
+               r = poll(pfd, 1, /*timeout:*/ 0);
+               /* Return 0 only if poll returns 1 ("one fd ready"), else return 1: */
+               return (const char *)(uintptr_t)(r <= 0);
+       }
+
+       if (params->opt_p && isatty(fd)) {
+               fputs(params->opt_p, stderr);
                fflush_all();
        }
 
+       ifs = params->ifs;
        if (ifs == NULL)
                ifs = defifs;
 
+       read_flags = params->read_flags;
        if (nchars || (read_flags & BUILTIN_READ_SILENT)) {
                tcgetattr(fd, &tty);
                old_tty = tty;
                if (nchars) {
                        tty.c_lflag &= ~ICANON;
-                       tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
+                       // Setting it to more than 1 breaks poll():
+                       // it blocks even if there's data. !??
+                       //tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
+                       /* reads will block only if < 1 char is available */
+                       tty.c_cc[VMIN] = 1;
+                       /* no timeout (reads block forever) */
+                       tty.c_cc[VTIME] = 0;
                }
                if (read_flags & BUILTIN_READ_SILENT) {
                        tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
@@ -146,55 +178,72 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
        retval = (const char *)(uintptr_t)0;
        startword = 1;
        backslash = 0;
-       if (end_ms) /* NB: end_ms stays nonzero: */
-               end_ms = ((unsigned)monotonic_ms() + end_ms) | 1;
+       if (params->opt_t)
+               end_ms += (unsigned)monotonic_ms();
        buffer = NULL;
        bufpos = 0;
+       delim = params->opt_d ? params->opt_d[0] : '\n';
        do {
                char c;
+               int timeout;
 
-               if (end_ms) {
-                       int timeout;
-                       struct pollfd pfd[1];
+               if ((bufpos & 0xff) == 0)
+                       buffer = xrealloc(buffer, bufpos + 0x101);
 
-                       pfd[0].fd = fd;
-                       pfd[0].events = POLLIN;
+               timeout = -1;
+               if (params->opt_t) {
                        timeout = end_ms - (unsigned)monotonic_ms();
-                       if (timeout <= 0 /* already late? */
-                        || safe_poll(pfd, 1, timeout) != 1 /* no? wait... */
-                       ) { /* timed out! */
+                       /* ^^^^^^^^^^^^^ all values are unsigned,
+                        * wrapping math is used here, good even if
+                        * 32-bit unix time wrapped (year 2038+).
+                        */
+                       if (timeout <= 0) { /* already late? */
                                retval = (const char *)(uintptr_t)1;
                                goto ret;
                        }
                }
 
-               if ((bufpos & 0xff) == 0)
-                       buffer = xrealloc(buffer, bufpos + 0x100);
-               if (nonblock_safe_read(fd, &buffer[bufpos], 1) != 1) {
+               /* We must poll even if timeout is -1:
+                * we want to be interrupted if signal arrives,
+                * regardless of SA_RESTART-ness of that signal!
+                */
+               errno = 0;
+               pfd[0].events = POLLIN;
+               if (poll(pfd, 1, timeout) <= 0) {
+                       /* timed out, or EINTR */
+                       err = errno;
+                       retval = (const char *)(uintptr_t)1;
+                       goto ret;
+               }
+               if (read(fd, &buffer[bufpos], 1) != 1) {
+                       err = errno;
                        retval = (const char *)(uintptr_t)1;
                        break;
                }
+
                c = buffer[bufpos];
                if (c == '\0')
                        continue;
-               if (backslash) {
-                       backslash = 0;
-                       if (c != '\n')
-                               goto put;
-                       continue;
-               }
-               if (!(read_flags & BUILTIN_READ_RAW) && c == '\\') {
-                       backslash = 1;
-                       continue;
+               if (!(read_flags & BUILTIN_READ_RAW)) {
+                       if (backslash) {
+                               backslash = 0;
+                               if (c != '\n')
+                                       goto put;
+                               continue;
+                       }
+                       if (c == '\\') {
+                               backslash = 1;
+                               continue;
+                       }
                }
-               if (c == '\n')
+               if (c == delim) /* '\n' or -d CHAR */
                        break;
 
                /* $IFS splitting. NOT done if we run "read"
                 * without variable names (bash compat).
                 * Thus, "read" and "read REPLY" are not the same.
                 */
-               if (argv[0]) {
+               if (!params->opt_d && argv[0]) {
 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
                        const char *is_ifs = strchr(ifs, c);
                        if (startword && is_ifs) {
@@ -209,7 +258,7 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
                        if (argv[1] != NULL && is_ifs) {
                                buffer[bufpos] = '\0';
                                bufpos = 0;
-                               setvar(*argv, buffer);
+                               params->setvar(*argv, buffer);
                                argv++;
                                /* can we skip one non-space ifs char? (2: yes) */
                                startword = isspace(c) ? 2 : 1;
@@ -222,25 +271,63 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
 
        if (argv[0]) {
                /* Remove trailing space $IFS chars */
-               while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
+               while (--bufpos >= 0
+                && isspace(buffer[bufpos])
+                && strchr(ifs, buffer[bufpos]) != NULL
+               ) {
                        continue;
+               }
                buffer[bufpos + 1] = '\0';
+
+               /* Last variable takes the entire remainder with delimiters
+                * (sans trailing whitespace $IFS),
+                * but ***only "if there are fewer vars than fields"(c)***!
+                * The "X:Y:" case below: there are two fields,
+                * and therefore last delimiter (:) is eaten:
+                * IFS=": "
+                * echo "X:Y:Z:"  | (read x y; echo "|$x|$y|") # |X|Y:Z:|
+                * echo "X:Y:Z"   | (read x y; echo "|$x|$y|") # |X|Y:Z|
+                * echo "X:Y:"    | (read x y; echo "|$x|$y|") # |X|Y|, not |X|Y:|
+                * echo "X:Y  : " | (read x y; echo "|$x|$y|") # |X|Y|
+                */
+               if (bufpos >= 0
+                && strchr(ifs, buffer[bufpos]) != NULL
+               ) {
+                       /* There _is_ a non-whitespace IFS char */
+                       /* Skip whitespace IFS char before it */
+                       while (--bufpos >= 0
+                        && isspace(buffer[bufpos])
+                        && strchr(ifs, buffer[bufpos]) != NULL
+                       ) {
+                               continue;
+                       }
+                       /* Are there $IFS chars? */
+                       if (strcspn(buffer, ifs) >= ++bufpos) {
+                               /* No: last var takes one field, not more */
+                               /* So, drop trailing IFS delims */
+                               buffer[bufpos] = '\0';
+                       }
+               }
+
                /* Use the remainder as a value for the next variable */
-               setvar(*argv, buffer);
+               params->setvar(*argv, buffer);
                /* Set the rest to "" */
                while (*++argv)
-                       setvar(*argv, "");
+                       params->setvar(*argv, "");
        } else {
                /* Note: no $IFS removal */
                buffer[bufpos] = '\0';
-               setvar("REPLY", buffer);
+               params->setvar("REPLY", buffer);
        }
 
  ret:
        free(buffer);
        if (read_flags & BUILTIN_READ_SILENT)
                tcsetattr(fd, TCSANOW, &old_tty);
+
+       errno = err;
        return retval;
+#undef fd
 }
 
 /* ulimit builtin */
@@ -286,6 +373,12 @@ static const struct limits limits_tbl[] = {
 #ifdef RLIMIT_LOCKS
        { RLIMIT_LOCKS,         0,      'w',    "locks" },
 #endif
+#ifdef RLIMIT_NICE
+       { RLIMIT_NICE,          0,      'e',    "scheduling priority" },
+#endif
+#ifdef RLIMIT_RTPRIO
+       { RLIMIT_RTPRIO,        0,      'r',    "real-time priority" },
+#endif
 };
 
 enum {
@@ -294,7 +387,7 @@ enum {
 };
 
 /* "-": treat args as parameters of option with ASCII code 1 */
-static const char ulimit_opt_string[] = "-HSa"
+static const char ulimit_opt_string[] ALIGN1 = "-HSa"
 #ifdef RLIMIT_FSIZE
                        "f::"
 #endif
@@ -327,6 +420,12 @@ static const char ulimit_opt_string[] = "-HSa"
 #endif
 #ifdef RLIMIT_LOCKS
                        "w::"
+#endif
+#ifdef RLIMIT_NICE
+                       "e::"
+#endif
+#ifdef RLIMIT_RTPRIO
+                       "r::"
 #endif
                        ;
 
@@ -340,7 +439,7 @@ static void printlim(unsigned opts, const struct rlimit *limit,
                val = limit->rlim_cur;
 
        if (val == RLIM_INFINITY)
-               printf("unlimited\n");
+               puts("unlimited");
        else {
                val >>= l->factor_shift;
                printf("%llu\n", (long long) val);
@@ -357,20 +456,12 @@ shell_builtin_ulimit(char **argv)
         * ulimit 123 -c2 -l 456
         */
 
-       /* In case getopt was already called:
-        * reset the libc getopt() function, which keeps internal state.
+       /* In case getopt() was already called:
+        * reset libc getopt() internal state.
         */
-#ifdef __GLIBC__
-       optind = 0;
-#else /* BSD style */
-       optind = 1;
-       /* optreset = 1; */
-#endif
-       /* optarg = NULL; opterr = 0; optopt = 0; - do we need this?? */
+       GETOPT_RESET();
 
-       argc = 1;
-       while (argv[argc])
-               argc++;
+       argc = string_array_len(argv);
 
        opts = 0;
        while (1) {
@@ -453,7 +544,6 @@ shell_builtin_ulimit(char **argv)
                        /* bad option. getopt already complained. */
                        break;
                }
-
        } /* while (there are options) */
 
        return 0;