Updates from both Vladimir and Larry
[oweals/busybox.git] / hush.c
diff --git a/hush.c b/hush.c
index 59568189fe2038a855685fe810a563d81afbee24..2b100983e788074c5561ec20e39ccd7077fb65db 100644 (file)
--- a/hush.c
+++ b/hush.c
 #define applet_name "hush"
 #include "standalone.h"
 #define shell_main main
-#define BB_FEATURE_SH_SIMPLE_PROMPT
+#undef BB_FEATURE_SH_FANCY_PROMPT
 #endif
 
 typedef enum {
@@ -227,6 +227,14 @@ struct close_me {
        struct close_me *next;
 };
 
+struct variables {
+       char *name;
+       char *value;
+       int flg_export;
+       int flg_read_only;
+       struct variables *next;
+};
+
 /* globals, connect us to the outside world
  * the first three support $?, $#, and $1 */
 char **global_argv;
@@ -249,12 +257,11 @@ static struct jobset *job_list;
 static unsigned int last_bg_pid;
 static char *PS1;
 static char *PS2;
-static char **__shell_local_env;
+struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
+struct variables *top_vars = &shell_ver;
 
 #define B_CHUNK (100)
 #define B_NOSPAC 1
-#define MAX_LINE 256       /* for cwd */
-#define MAX_READ 256       /* for builtin_read */
 
 typedef struct {
        char *data;
@@ -303,12 +310,12 @@ static void debug_printf(const char *format, ...)
        va_end(args);
 }
 #else
-static void debug_printf(const char *format, ...) { }
+static inline void debug_printf(const char *format, ...) { }
 #endif
 #define final_printf debug_printf
 
-void __syntax(char *file, int line) {
-       fprintf(stderr,"syntax error %s:%d\n",file,line);
+static void __syntax(char *file, int line) {
+       error_msg("syntax error %s:%d", file, line);
 }
 #define syntax() __syntax(__FILE__, __LINE__)
 
@@ -356,13 +363,13 @@ static int setup_redirects(struct child_prog *prog, int squirrel[]);
 static int pipe_wait(struct pipe *pi);
 static int run_list_real(struct pipe *pi);
 static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn));
+int controlling_tty(int check_pgrp);
 static int run_pipe_real(struct pipe *pi);
 /*   extended glob support: */
 static int globhack(const char *src, int flags, glob_t *pglob);
 static int glob_needed(const char *s);
 static int xglob(o_string *dest, int flags, glob_t *pglob);
 /*   variable assignment: */
-static int set_local_var(const char *s);
 static int is_assignment(const char *s);
 /*   data structure manipulation: */
 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
@@ -390,8 +397,8 @@ static void remove_bg_job(struct pipe *pi);
 static void free_pipe(struct pipe *pi);
 /*     local variable support */
 static char *get_local_var(const char *var);
-static int   set_local_var(const char *s);
 static void  unset_local_var(const char *name);
+static int set_local_var(const char *s, int flg_export);
 
 
 /* Table of built-in functions.  They can be forked or not, depending on
@@ -427,6 +434,17 @@ static struct built_in_command bltins[] = {
        {NULL, NULL, NULL}
 };
 
+static const char *set_cwd(void)
+{
+       if(cwd==unknown)
+               cwd = NULL;     /* xgetcwd(arg) called free(arg) */
+       cwd = xgetcwd((char *)cwd);
+       if (!cwd)
+               cwd = unknown;
+       return cwd;
+}
+
+
 /* built-in 'cd <path>' handler */
 static int builtin_cd(struct child_prog *child)
 {
@@ -439,9 +457,7 @@ static int builtin_cd(struct child_prog *child)
                printf("cd: %s: %s\n", newdir, strerror(errno));
                return EXIT_FAILURE;
        }
-       cwd = xgetcwd((char *)cwd);
-       if (!cwd)
-               cwd = unknown;
+       set_cwd();
        return EXIT_SUCCESS;
 }
 
@@ -477,43 +493,48 @@ static int builtin_exit(struct child_prog *child)
 /* built-in 'export VAR=value' handler */
 static int builtin_export(struct child_prog *child)
 {
-       int res;
-       char *value, *name = child->argv[1];
+       int res = 0;
+       char *name = child->argv[1];
 
        if (name == NULL) {
                return (builtin_env(child));
        }
 
-       value = strchr(name, '=');
-       if (!value) {
-               /* They are exporting something without an =VALUE.
-                * Assume this is a local shell variable they are exporting */
-               name = get_local_var(name);
-               if (! name ) { 
-                       error_msg("export failed");
-                       return (EXIT_FAILURE);
+       name = strdup(name);
+
+       if(name) {
+               char *value = strchr(name, '=');
+
+               if (!value) {
+                       char *tmp;
+                       /* They are exporting something without an =VALUE */
+
+                       value = get_local_var(name);
+                       if (value) {
+                               size_t ln = strlen(name);
+
+                               tmp = realloc(name, ln+strlen(value)+2);
+                               if(tmp==NULL)
+                                       res = -1;
+                               else {
+                                       sprintf(tmp+ln, "=%s", value);
+                                       name = tmp;
+                               }
+                       } else {
+                               /* bash does not return an error when trying to export
+                                * an undefined variable.  Do likewise. */
+                               res = 1;
+                       }
                }
-               /* FIXME -- I leak memory!!!!! */
-               value = malloc(strlen(child->argv[1]) + strlen(name) + 2);
-               sprintf(value, "%s=%s", child->argv[1], name);
-       } else {
-               /* Bourne shells always put exported variables into the 
-                * local shell variable list.  Do that first... */
-               set_local_var(name);
-               /* FIXME -- I leak memory!!!!! */
-               value = strdup(name);
-       }
-
-       /* FIXME -- I leak memory!!!!!
-        * It seems most putenv implementations place the very char* pointer
-        * we pass in directly into the environ array, so the memory holding
-        * this string has to be persistant.  We can't even use the memory for
-        * the local shell variable list, since where that memory is keeps 
-        * changing due to reallocs... */
-       res = putenv(value);
-       if (res)
+       }
+       if (res<0)
                perror_msg("export");
-       return (res);
+       else if(res==0)
+               res = set_local_var(name, 1);
+       else
+               res = 0;
+       free(name);
+       return res;
 }
 
 /* built-in 'fg' and 'bg' handler */
@@ -554,7 +575,7 @@ static int builtin_fg_bg(struct child_prog *child)
                signal(SIGTTOU, SIG_IGN);
                /* suppress messages when run from /linuxrc mag@sysgo.de */
                if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
-                       perror_msg("tcsetpgrp"); 
+                       perror_msg("tcsetpgrp-1"); 
                signal(SIGTTOU, SIG_DFL);
                job_list->fg = pi;
        }
@@ -605,66 +626,52 @@ static int builtin_jobs(struct child_prog *child)
 /* built-in 'pwd' handler */
 static int builtin_pwd(struct child_prog *dummy)
 {
-       cwd = xgetcwd((char *)cwd);
-       if (!cwd)
-               cwd = unknown;
-       puts(cwd);
+       puts(set_cwd());
        return EXIT_SUCCESS;
 }
 
 /* built-in 'read VAR' handler */
 static int builtin_read(struct child_prog *child)
 {
-       int res = 0, len, newlen;
-       char *s;
-       char string[MAX_READ];
+       int res;
 
        if (child->argv[1]) {
-               /* argument (VAR) given: put "VAR=" into buffer */
-               strcpy(string, child->argv[1]);
-               len = strlen(string);
-               string[len++] = '=';
-               string[len]   = '\0';
-               /* XXX would it be better to go through in_str? */
-               fgets(&string[len], sizeof(string) - len, stdin);       /* read string */
-               newlen = strlen(string);
-               if(newlen > len)
-                       string[--newlen] = '\0';        /* chomp trailing newline */
-               /*
-               ** string should now contain "VAR=<value>"
-               ** copy it (putenv() won't do that, so we must make sure
-               ** the string resides in a static buffer!)
-               */
-               res = -1;
-               if((s = strdup(string)))
-                       res = putenv(s);
+               char string[BUFSIZ];
+               char *var = 0;
+
+               string[0] = 0;  /* In case stdin has only EOF */
+               /* read string */
+               fgets(string, sizeof(string), stdin);
+               chomp(string);
+               var = malloc(strlen(child->argv[1])+strlen(string)+2);
+               if(var) {
+                       sprintf(var, "%s=%s", child->argv[1], string);
+                       res = set_local_var(var, 0);
+               } else
+                       res = -1;
                if (res)
-                       fprintf(stderr, "read: %s\n", strerror(errno));
+                       fprintf(stderr, "read: %m\n");
+               free(var);      /* So not move up to avoid breaking errno */
+               return res;
+       } else {
+               do res=getchar(); while(res!='\n' && res!=EOF);
+               return 0;
        }
-       else
-               fgets(string, sizeof(string), stdin);
-
-       return (res);
 }
 
 /* built-in 'set VAR=value' handler */
 static int builtin_set(struct child_prog *child)
 {
-       int res;
        char *temp = child->argv[1];
+       struct variables *e;
+
+       if (temp == NULL)
+               for(e = top_vars; e; e=e->next)
+                       printf("%s=%s\n", e->name, e->value);
+       else
+               set_local_var(temp, 0);
 
-       if (child->argv[1] == NULL) {
-               char **e = __shell_local_env;
-               if (e == NULL) return EXIT_FAILURE;
-               for (; *e; e++) {
-                       puts(*e);
-               }
                return EXIT_SUCCESS;
-       }
-       res = set_local_var(temp);
-       if (res)
-               fprintf(stderr, "set: %s\n", strerror(errno));
-       return (res);
 }
 
 
@@ -697,7 +704,7 @@ static int builtin_source(struct child_prog *child)
        /* XXX search through $PATH is missing */
        input = fopen(child->argv[1], "r");
        if (!input) {
-               fprintf(stderr, "Couldn't open file '%s'\n", child->argv[1]);
+               error_msg("Couldn't open file '%s'", child->argv[1]);
                return EXIT_FAILURE;
        }
 
@@ -732,11 +739,7 @@ static int builtin_umask(struct child_prog *child)
 /* built-in 'unset VAR' handler */
 static int builtin_unset(struct child_prog *child)
 {
-       if (child->argv[1] == NULL) {
-               fprintf(stderr, "unset: parameter required.\n");
-               return EXIT_FAILURE;
-       }
-       unsetenv(child->argv[1]);
+       /* bash returned already true */
        unset_local_var(child->argv[1]);
        return EXIT_SUCCESS;
 }
@@ -838,7 +841,7 @@ static int static_peek(struct in_str *i)
 
 static inline void cmdedit_set_initial_prompt(void)
 {
-#ifdef BB_FEATURE_SH_SIMPLE_PROMPT
+#ifndef BB_FEATURE_SH_FANCY_PROMPT
        PS1 = NULL;
 #else
        PS1 = getenv("PS1");
@@ -850,7 +853,7 @@ static inline void cmdedit_set_initial_prompt(void)
 static inline void setup_prompt_string(int promptmode, char **prompt_str)
 {
        debug_printf("setup_prompt_string %d ",promptmode);
-#ifdef BB_FEATURE_SH_SIMPLE_PROMPT
+#ifndef BB_FEATURE_SH_FANCY_PROMPT
        /* Set up the prompt */
        if (promptmode == 1) {
                if (PS1)
@@ -998,8 +1001,7 @@ static int setup_redirects(struct child_prog *prog, int squirrel[])
                        if (openfd < 0) {
                        /* this could get lost if stderr has been redirected, but
                           bash and ash both lose it as well (though zsh doesn't!) */
-                               fprintf(stderr,"error opening %s: %s\n", redir->word.gl_pathv[0],
-                                       strerror(errno));
+                               perror_msg("error opening %s", redir->word.gl_pathv[0]);
                                return 1;
                        }
                } else {
@@ -1056,13 +1058,17 @@ static int pipe_wait(struct pipe *pi)
        return rcode;
 }
 
-/* very simple version for testing */
+/* never returns */
+/* XXX no exit() here.  If you don't exec, use _exit instead.
+ * The at_exit handlers apparently confuse the calling process,
+ * in particular stdin handling.  Not sure why? */
 static void pseudo_exec(struct child_prog *child)
 {
        int i, rcode;
        struct built_in_command *x;
        if (child->argv) {
                for (i=0; is_assignment(child->argv[i]); i++) {
+                       debug_printf("pid %d environment modification: %s\n",getpid(),child->argv[i]);
                        putenv(strdup(child->argv[i]));
                }
                child->argv+=i;  /* XXX this hack isn't so horrible, since we are about
@@ -1071,7 +1077,9 @@ static void pseudo_exec(struct child_prog *child)
                /* If a variable is assigned in a forest, and nobody listens,
                 * was it ever really set?
                 */
-               if (child->argv[0] == NULL) exit(EXIT_SUCCESS);
+               if (child->argv[0] == NULL) {
+                       _exit(EXIT_SUCCESS);
+               }
 
                /*
                 * Check if the command matches any of the builtins.
@@ -1082,7 +1090,7 @@ static void pseudo_exec(struct child_prog *child)
                for (x = bltins; x->cmd; x++) {
                        if (strcmp(child->argv[0], x->cmd) == 0 ) {
                                debug_printf("builtin exec %s\n", child->argv[0]);
-                               exit(x->function(child));
+                               _exit(x->function(child));
                        }
                }
 
@@ -1122,19 +1130,19 @@ static void pseudo_exec(struct child_prog *child)
 #endif
                debug_printf("exec of %s\n",child->argv[0]);
                execvp(child->argv[0],child->argv);
-               perror("execvp");
-               exit(1);
+               perror_msg("couldn't exec: %s",child->argv[0]);
+               _exit(1);
        } else if (child->group) {
                debug_printf("runtime nesting to group\n");
                interactive=0;    /* crucial!!!! */
                rcode = run_list_real(child->group);
                /* OK to leak memory by not calling run_list_test,
                 * since this process is about to exit */
-               exit(rcode);
+               _exit(rcode);
        } else {
                /* Can happen.  See what bash does with ">foo" by itself. */
                debug_printf("trying to pseudo_exec null command\n");
-               exit(EXIT_SUCCESS);
+               _exit(EXIT_SUCCESS);
        }
 }
 
@@ -1160,10 +1168,9 @@ static void insert_bg_job(struct pipe *pi)
        /* physically copy the struct job */
        memcpy(thejob, pi, sizeof(struct pipe));
        thejob->next = NULL;
-       //thejob->num_progs = 0;
        thejob->running_progs = thejob->num_progs;
        thejob->stopped_progs = 0;
-       thejob->text = xmalloc(MAX_LINE);
+       thejob->text = xmalloc(BUFSIZ); /* cmdedit buffer size */
 
        //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
        {
@@ -1222,7 +1229,7 @@ static void free_pipe(struct pipe *pi)
    have, figure out why and see if a job has completed */
 static void checkjobs()
 {
-       int status;
+       int status, ctty;
        int prognum = 0;
        struct pipe *pi;
        pid_t childpid;
@@ -1262,8 +1269,31 @@ static void checkjobs()
                perror_msg("waitpid");
 
        /* move the shell to the foreground */
-       if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
-               perror_msg("tcsetpgrp"); 
+       if (interactive && (ctty=controlling_tty(0))!=-1) {
+               if (tcsetpgrp(ctty, getpgrp()))
+                       perror_msg("tcsetpgrp-2");
+       }
+}
+
+/* Figure out our controlling tty, checking in order stderr,
+ * stdin, and stdout.  If check_pgrp is set, also check that
+ * we belong to the foreground process group associated with
+ * that tty.  The value of ctty is needed in order to call
+ * tcsetpgrp(ctty, ...); */
+int controlling_tty(int check_pgrp)
+{
+       pid_t curpgrp;
+       int ctty;
+
+       if ((curpgrp = tcgetpgrp(ctty = 2)) < 0
+               && (curpgrp = tcgetpgrp(ctty = 0)) < 0
+               && (curpgrp = tcgetpgrp(ctty = 1)) < 0)
+               return errno = ENOTTY, -1;
+
+       if (check_pgrp && curpgrp != getpgrp())
+               return errno = EPERM, -1;
+
+       return ctty;
 }
 
 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
@@ -1293,17 +1323,11 @@ static int run_pipe_real(struct pipe *pi)
 
        ctty = -1;
        nextin = 0;
-       pi->pgrp = 0;
+       pi->pgrp = -1;
 
        /* Check if we are supposed to run in the foreground */
        if (interactive && pi->followup!=PIPE_BG) {
-               if ((pi->pgrp = tcgetpgrp(ctty = 2)) < 0
-                               && (pi->pgrp = tcgetpgrp(ctty = 0)) < 0
-                               && (pi->pgrp = tcgetpgrp(ctty = 1)) < 0)
-                       return errno = ENOTTY, -1;
-
-               if (pi->pgrp < 0 && pi->pgrp != getpgrp())
-                       return errno = EPERM, -1;
+               if ((ctty = controlling_tty(pi->pgrp<0)) < 0) return -1;
        }
 
        /* Check if this is a simple builtin (not part of a pipe).
@@ -1327,7 +1351,7 @@ static int run_pipe_real(struct pipe *pi)
                if (i!=0 && child->argv[i]==NULL) {
                        /* assignments, but no command: set the local environment */
                        for (i=0; child->argv[i]!=NULL; i++) {
-                               set_local_var(child->argv[i]);
+                               set_local_var(child->argv[i], 0);
                        }
                        return EXIT_SUCCESS;   /* don't worry about errors in set_local_var() yet */
                }
@@ -1393,11 +1417,11 @@ static int run_pipe_real(struct pipe *pi)
                         * and the pipe fd is available for dup'ing. */
                        setup_redirects(child,NULL);
                        
-                       if (pi->followup!=PIPE_BG) {
+                       if (interactive && pi->followup!=PIPE_BG) {
                                /* If we (the child) win the race, put ourselves in the process
                                 * group whose leader is the first process in this pipe. */
                                if (pi->pgrp < 0) {
-                                       pi->pgrp = child->pid;
+                                       pi->pgrp = getpid();
                                }
                                if (setpgid(0, pi->pgrp) == 0) {
                                        signal(SIGTTOU, SIG_IGN);
@@ -1459,13 +1483,15 @@ static int run_list_real(struct pipe *pi)
                        if (interactive) {
                                /* move the new process group into the foreground */
                                /* suppress messages when run from /linuxrc mag@sysgo.de */
+                               /* XXX probably this "0" should come from controlling_tty() */
                                if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
-                                       perror_msg("tcsetpgrp");
+                                       perror_msg("tcsetpgrp-3");
                                rcode = pipe_wait(pi);
                                if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
-                                       perror_msg("tcsetpgrp");
+                                       perror_msg("tcsetpgrp-4");
                        } else {
                                rcode = pipe_wait(pi);
+                               debug_printf("pipe_wait returned %d\n",rcode);
                        }
                }
                last_return_code=rcode;
@@ -1646,12 +1672,10 @@ static int xglob(o_string *dest, int flags, glob_t *pglob)
                gr = globhack(dest->data, flags, pglob);
                debug_printf("globhack returned %d\n",gr);
        }
-       if (gr == GLOB_NOSPACE) {
-               fprintf(stderr,"out of memory during glob\n");
-               exit(1);
-       }
+       if (gr == GLOB_NOSPACE)
+               error_msg_and_die("out of memory during glob");
        if (gr != 0) { /* GLOB_ABORTED ? */
-               fprintf(stderr,"glob(3) error %d\n",gr);
+               error_msg("glob(3) error %d",gr);
        }
        /* globprint(glob_target); */
        return gr;
@@ -1660,129 +1684,120 @@ static int xglob(o_string *dest, int flags, glob_t *pglob)
 /* This is used to get/check local shell variables */
 static char *get_local_var(const char *s)
 {
-       char **p;
-       int len;
+       struct variables *cur;
 
        if (!s)
                return NULL;
-       if (!__shell_local_env)
-               return NULL;
-       len = strlen(s);
-
-       for (p = __shell_local_env; *p; p++) {
-               if (memcmp(s, *p, len) == 0 && (*p)[len] == '=') {
-                       return *p + len + 1;
-               }
-       }
+       for (cur = top_vars; cur; cur=cur->next)
+               if(strcmp(cur->name, s)==0)
+                       return cur->value;
        return NULL;
 }
 
-/* This is used to set local shell variables */
-static int set_local_var(const char *s)
+/* This is used to set local shell variables
+   flg_export==0 if only local (not exporting) variable
+   flg_export==1 if "new" exporting environ
+   flg_export>1  if current startup environ (not call putenv()) */
+static int set_local_var(const char *s, int flg_export)
 {
-       char **ep;
-       char *tmp,*name, *value;
-       size_t size;
-       size_t namelen;
-       size_t vallen;
+       char *name, *value;
        int result=0;
+       struct variables *cur;
+       char *newval = 0;
 
-       name=tmp=strdup(s);
+       name=strdup(s);
 
        /* Assume when we enter this function that we are already in
         * NAME=VALUE format.  So the first order of business is to
         * split 's' on the '=' into 'name' and 'value' */ 
        value = strchr(name, '=');
-       if (!value) {
+       if (value==0 || (newval = strdup(value+1))==0) {
                result = -1;
-               goto done_already;
-       }
-       *value='\0';
-       ++value;
-
-       namelen = strlen (name);
-       vallen = strlen (value);
-
-       /* Now see how many local environment entries we have, and check
-        * if we match an existing environment entry (so we can overwrite it) */
-       size = 0;
-       for (ep = __shell_local_env; ep && *ep != NULL; ++ep) {
-               if (!memcmp (*ep, name, namelen) && (*ep)[namelen] == '=')
-                       break;
-               else
-                       ++size;
-       }
+       } else {
+               *value++ = 0;
 
-       if (ep == NULL || *ep == NULL) {
-               static char **last_environ = NULL;
-               char **new_environ = (char **) malloc((size + 2) * sizeof(char *));
-               if (new_environ == NULL) {
-                       result = -1;
-                       goto done_already;
-               }
-               memcpy((__ptr_t) new_environ, (__ptr_t) __shell_local_env, 
-                               size * sizeof(char *));
-
-               new_environ[size] = malloc (namelen + 1 + vallen + 1);
-               if (new_environ[size] == NULL) {
-                       free (new_environ);
-                       errno=ENOMEM;
-                       result = -1;
-                       goto done_already;
+               for(cur = top_vars; cur; cur = cur->next) {
+                       if(strcmp(cur->name, name)==0)
+                               break;
                }
-               memcpy (new_environ[size], name, namelen);
-               new_environ[size][namelen] = '=';
-               memcpy (&new_environ[size][namelen + 1], value, vallen + 1);
-
-               new_environ[size + 1] = NULL;
-
-               if (last_environ != NULL)
-                       free ((__ptr_t) last_environ);
-               last_environ = new_environ;
-               __shell_local_env = new_environ;
-       }
-       else {
-               size_t len = strlen (*ep);
-               if (len < namelen + 1 + vallen) {
-                       char *new = malloc (namelen + 1 + vallen + 1);
-                       if (new == NULL) {
+
+               if(cur) {
+                       if(strcmp(cur->value, value)==0) {
+                               if(flg_export>0 && cur->flg_export==0)
+                                       cur->flg_export=flg_export;
+                               else
+                                       result++;
+                       } else {
+                               if(cur->flg_read_only) {
+                                       result = -1;
+                                       error_msg("%s: readonly variable", name);
+                               } else {
+                                       if(flg_export>0 || cur->flg_export>1)
+                                               cur->flg_export=1;
+                                       free(cur->value);
+                                       cur->value = newval;
+                                       newval = 0; /* protect free */
+                               }
+                       }
+               } else {
+                       cur = malloc(sizeof(struct variables));
+                       if(cur==0) {
                                result = -1;
-                               goto done_already;
+                       } else {
+                               cur->name = strdup(name);
+                               if(cur->name == 0) {
+                                       free(cur);
+                                       result = -1;
+                               } else {
+                                       struct variables *bottom = top_vars;
+                                       cur->value = newval;
+                                       newval = 0;     /* protect free */
+                                       cur->next = 0;
+                                       cur->flg_export = flg_export;
+                                       cur->flg_read_only = 0;
+                                       while(bottom->next) bottom=bottom->next;
+                                       bottom->next = cur;
+                               }
                        }
-                       *ep = new;
-                       memcpy (*ep, name, namelen);
-                       (*ep)[namelen] = '=';
                }
-               memcpy (&(*ep)[namelen + 1], value, vallen + 1);
        }
 
-       /* One last little detail...  If this variable is already
-        * in the environment we must set it there as well... */
-       tmp = getenv(name);
-       if (tmp) { 
-               /* FIXME -- I leak memory!!!!! */
-               putenv(strdup(s));
+       if(result==0 && cur->flg_export==1) {
+               *(value-1) = '=';
+               result = putenv(name);
+       } else {
+               free(name);
+               if(result>0)            /* equivalent to previous set */
+                       result = 0;
        }
-
-done_already:
-       free(name);
+       free(newval);
        return result;
 }
 
 static void unset_local_var(const char *name)
 {
-       char **ep, **dp;
-       size_t namelen;
-
-       if (!name)
-               return;
-       namelen = strlen(name);
-       for (dp = ep = __shell_local_env; ep && *ep != NULL; ++ep) {
-               if (memcmp (*ep, name, namelen)==0 && (*ep)[namelen] == '=') {
-                       *dp = *ep;
-                       ++dp;
-                       *ep = NULL;
-                       break;
+       struct variables *cur;
+
+       if (name) {
+               for (cur = top_vars; cur; cur=cur->next) {
+                       if(strcmp(cur->name, name)==0)
+                               break;
+               }
+               if(cur!=0) {
+                       struct variables *next = top_vars;
+                       if(cur->flg_read_only) {
+                               error_msg("%s: readonly variable", name);
+                               return;
+                       } else {
+                               if(cur->flg_export)
+                                       unsetenv(cur->name);
+                               free(cur->name);
+                               free(cur->value);
+                               while (next->next != cur)
+                                       next = next->next;
+                               next->next = cur->next;
+                       }
+                       free(cur);
                }
        }
 }
@@ -1963,7 +1978,7 @@ static int done_word(o_string *dest, struct p_context *ctx)
        if (ctx->pending_redirect) {
                ctx->pending_redirect=NULL;
                if (glob_target->gl_pathc != 1) {
-                       fprintf(stderr, "ambiguous redirect\n");
+                       error_msg("ambiguous redirect");
                        return 1;
                }
        } else {
@@ -2049,7 +2064,7 @@ static int redirect_dup_num(struct in_str *input)
        }
        if (ok) return d;
 
-       fprintf(stderr, "ambiguous redirect\n");
+       error_msg("ambiguous redirect");
        return -2;
 }
 
@@ -2098,9 +2113,9 @@ FILE *generate_stream_from_list(struct pipe *head)
 #if 0
 #define SURROGATE "surrogate response"
                write(1,SURROGATE,sizeof(SURROGATE));
-               exit(run_list(head));
+               _exit(run_list(head));
 #else
-               exit(run_list_real(head));   /* leaks memory */
+               _exit(run_list_real(head));   /* leaks memory */
 #endif
        }
        debug_printf("forked child %d\n",pid);
@@ -2261,7 +2276,7 @@ static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *i
                case '-':
                case '_':
                        /* still unhandled, but should be eventually */
-                       fprintf(stderr,"unhandled syntax: $%c\n",ch);
+                       error_msg("unhandled syntax: $%c",ch);
                        return 1;
                        break;
                default:
@@ -2500,44 +2515,73 @@ static int parse_file_outer(FILE *f)
        return rcode;
 }
 
+
+/* I think Erik wrote this.  It looks imperfect at best */
+void grab_tty_control(void)
+{
+       pid_t initialpgrp;
+       do {
+               initialpgrp = tcgetpgrp(fileno(stderr));
+               if (initialpgrp < 0) {
+                       error_msg("sh: can't access tty; job control disabled\n");
+               }
+               if (initialpgrp == -1)
+                       initialpgrp = getpgrp();
+               else if (initialpgrp != getpgrp()) {
+                       killpg(initialpgrp, SIGTTIN);
+                       continue;
+               }
+       } while (0);
+}
+
 int shell_main(int argc, char **argv)
 {
        int opt;
        FILE *input;
        struct jobset joblist_end = { NULL, NULL };
+       char **e = environ;
+
+       /* FIXME */
+       fprintf(stderr, "sizeof(map)=%d\n", sizeof(map));
 
-       /* (re?) initialize globals */
-       ifs=NULL;
-       fake_mode=0;
-       interactive=0;
+
+       /* XXX what should these be while sourcing /etc/profile? */
+       global_argc = argc;
+       global_argv = argv;
+       
+       /* (re?) initialize globals.  Sometimes shell_main() ends up calling
+        * shell_main(), therefore we cannot rely on the BSS to zero out this 
+        * stuff.  Reset these to 0 every time. */
+       ifs = NULL;
+       memset(map,0,sizeof(map));
+       fake_mode = 0;
+       interactive = 0;
        close_me_head = NULL;
+       last_bg_pid = 0;
+
+       /* Initialize some more globals to non-zero values */
+       set_cwd();
        job_list = &joblist_end;
-       last_bg_pid=0;
+#ifdef BB_FEATURE_COMMAND_EDITING
+       cmdedit_set_initial_prompt();
+#else
+       PS1 = NULL;
+#endif
        PS2 = "> ";
-       __shell_local_env = 0;
+
+       /* initialize our shell local variables with the values 
+        * currently living in the environment */
+       if (e) {
+               for (; *e; e++)
+                       set_local_var(*e, 2);   /* without call putenv() */
+       }
 
        last_return_code=EXIT_SUCCESS;
 
-       /* XXX what should these be while sourcing /etc/profile? */
-       global_argc = argc;
-       global_argv = argv;
 
        /* If we get started under a job aware app (like bash 
         * for example), make sure we are now in charge so we 
         * don't fight over who gets the foreground */
-       do { 
-               pid_t initialpgrp;
-               initialpgrp = tcgetpgrp(fileno(stderr));
-               if (initialpgrp < 0) {
-                       error_msg_and_die("sh: can't access tty; job control disabled\n");
-               }
-               if (initialpgrp == -1)
-                       initialpgrp = getpgrp();
-               else if (initialpgrp != getpgrp()) {
-                       killpg(initialpgrp, SIGTTIN);
-                       continue;
-               }
-       } while (0);
        /* don't pay any attention to this signal; it just confuses 
           things and isn't really meant for shells anyway */
        signal(SIGTTOU, SIG_IGN);
@@ -2554,16 +2598,6 @@ int shell_main(int argc, char **argv)
        }
        input=stdin;
        
-       /* initialize the cwd -- this is never freed...*/
-       cwd = xgetcwd(0);
-       if (!cwd)
-               cwd = unknown;
-#ifdef BB_FEATURE_COMMAND_EDITING
-       cmdedit_set_initial_prompt();
-#else
-       PS1 = NULL;
-#endif
-       
        while ((opt = getopt(argc, argv, "c:xif")) > 0) {
                switch (opt) {
                        case 'c':
@@ -2581,9 +2615,13 @@ int shell_main(int argc, char **argv)
                                fake_mode++;
                                break;
                        default:
+#ifndef BB_VER
                                fprintf(stderr, "Usage: sh [FILE]...\n"
                                                "   or: sh -c command [args]...\n\n");
                                exit(EXIT_FAILURE);
+#else
+                               show_usage();
+#endif
                }
        }
        /* A shell is interactive if the `-i' flag was given, or if all of
@@ -2602,6 +2640,9 @@ int shell_main(int argc, char **argv)
        if (interactive) {
                /* Looks like they want an interactive shell */
                fprintf(stdout, "\nhush -- the humble shell v0.01 (testing)\n\n");
+               grab_tty_control();
+       }
+       if (argv[optind]==NULL) {
                opt=parse_file_outer(stdin);
                goto final_return;
        }