Re-organized some sections and added a whole new section on avoiding the
[oweals/busybox.git] / sh.c
diff --git a/sh.c b/sh.c
index b96b46456814a4e36e6d5d9458c2b39fbf06f7d0..7f5b9060207c30bb20c33de7a2e688c2948577d0 100644 (file)
--- a/sh.c
+++ b/sh.c
  *
  */
 
-#include "internal.h"
+
+//#define BB_FEATURE_SH_BACKTICKS
+//#define BB_FEATURE_SH_IF_EXPRESSIONS
+#define BB_FEATURE_SH_ENVIRONMENT
+//#define DEBUG_SHELL
+
+
+#include "busybox.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <ctype.h>
 #include <sys/ioctl.h>
 #include <sys/wait.h>
 #include <unistd.h>
+#include <getopt.h>
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
 #include "cmdedit.h"
 #endif
 
-
+#define MAX_LINE       256     /* size of input buffer for `read' builtin */
+#define MAX_READ       128     /* size of input buffer for `read' builtin */
 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
 
 
@@ -49,6 +58,13 @@ enum redirectionType { REDIRECT_INPUT, REDIRECT_OVERWRITE,
        REDIRECT_APPEND
 };
 
+static const unsigned int REGULAR_JOB_CONTEXT=0x1;
+static const unsigned int IF_TRUE_CONTEXT=0x2;
+static const unsigned int IF_FALSE_CONTEXT=0x4;
+static const unsigned int THEN_EXP_CONTEXT=0x8;
+static const unsigned int ELSE_EXP_CONTEXT=0x10;
+
+
 struct jobSet {
        struct job *head;                       /* head of list of running jobs */
        struct job *fg;                         /* current foreground job */
@@ -80,63 +96,94 @@ struct job {
        struct childProgram *progs;     /* array of programs in job */
        struct job *next;                       /* to track background commands */
        int stoppedProgs;                       /* number of programs alive, but stopped */
+       int jobContext;                         /* bitmask defining current context */
 };
 
 struct builtInCommand {
        char *cmd;                                      /* name */
        char *descr;                            /* description */
-       char *usage;                            /* usage */
        int (*function) (struct job *, struct jobSet * jobList);        /* function ptr */
 };
 
-/* Some function prototypes */
-static int shell_cd(struct job *cmd, struct jobSet *junk);
-static int shell_env(struct job *dummy, struct jobSet *junk);
-static int shell_exit(struct job *cmd, struct jobSet *junk);
-static int shell_fg_bg(struct job *cmd, struct jobSet *jobList);
-static int shell_help(struct job *cmd, struct jobSet *junk);
-static int shell_jobs(struct job *dummy, struct jobSet *jobList);
-static int shell_pwd(struct job *dummy, struct jobSet *junk);
-static int shell_export(struct job *cmd, struct jobSet *junk);
-static int shell_source(struct job *cmd, struct jobSet *jobList);
-static int shell_unset(struct job *cmd, struct jobSet *junk);
+/* function prototypes for builtins */
+static int builtin_cd(struct job *cmd, struct jobSet *junk);
+static int builtin_env(struct job *dummy, struct jobSet *junk);
+static int builtin_exec(struct job *cmd, struct jobSet *junk);
+static int builtin_exit(struct job *cmd, struct jobSet *junk);
+static int builtin_fg_bg(struct job *cmd, struct jobSet *jobList);
+static int builtin_help(struct job *cmd, struct jobSet *junk);
+static int builtin_jobs(struct job *dummy, struct jobSet *jobList);
+static int builtin_pwd(struct job *dummy, struct jobSet *junk);
+static int builtin_export(struct job *cmd, struct jobSet *junk);
+static int builtin_source(struct job *cmd, struct jobSet *jobList);
+static int builtin_unset(struct job *cmd, struct jobSet *junk);
+static int builtin_read(struct job *cmd, struct jobSet *junk);
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+static int builtin_if(struct job *cmd, struct jobSet *junk);
+static int builtin_then(struct job *cmd, struct jobSet *junk);
+static int builtin_else(struct job *cmd, struct jobSet *junk);
+static int builtin_fi(struct job *cmd, struct jobSet *junk);
+#endif
+
 
+/* function prototypes for shell stuff */
 static void checkJobs(struct jobSet *jobList);
 static int getCommand(FILE * source, char *command);
-static int parseCommand(char **commandPtr, struct job *job, int *isBg);
-static int setupRedirections(struct childProgram *prog);
-static int runCommand(struct job newJob, struct jobSet *jobList, int inBg);
+static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobList, int *inBg);
+static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int outPipe[2]);
 static int busy_loop(FILE * input);
 
 
-/* Table of built-in functions */
+/* Table of built-in functions (these are non-forking builtins, meaning they
+ * can change global variables in the parent shell process but they will not
+ * work with pipes and redirects; 'unset foo | whatever' will not work) */
 static struct builtInCommand bltins[] = {
-       {"bg", "Resume a job in the background", "bg [%%job]", shell_fg_bg},
-       {"cd", "Change working directory", "cd [dir]", shell_cd},
-       {"env", "Print all environment variables", "env", shell_env},
-       {"exit", "Exit from shell()", "exit", shell_exit},
-       {"fg", "Bring job into the foreground", "fg [%%job]", shell_fg_bg},
-       {"jobs", "Lists the active jobs", "jobs", shell_jobs},
-       {"pwd", "Print current directory", "pwd", shell_pwd},
-       {"export", "Set environment variable", "export [VAR=value]", shell_export},
-       {"unset", "Unset environment variable", "unset VAR", shell_unset},
-       {".", "Source-in and run commands in a file", ". filename", shell_source},
-       {"help", "List shell built-in commands", "help", shell_help},
-       {NULL, NULL, NULL, NULL}
+       {"bg", "Resume a job in the background", builtin_fg_bg},
+       {"cd", "Change working directory", builtin_cd},
+       {"exec", "Exec command, replacing this shell with the exec'd process", builtin_exec},
+       {"exit", "Exit from shell()", builtin_exit},
+       {"fg", "Bring job into the foreground", builtin_fg_bg},
+       {"jobs", "Lists the active jobs", builtin_jobs},
+       {"export", "Set environment variable", builtin_export},
+       {"unset", "Unset environment variable", builtin_unset},
+       {"read", "Input environment variable", builtin_read},
+       {".", "Source-in and run commands in a file", builtin_source},
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+       {"if", NULL, builtin_if},
+       {"then", NULL, builtin_then},
+       {"else", NULL, builtin_else},
+       {"fi", NULL, builtin_fi},
+#endif
+       {NULL, NULL, NULL}
 };
 
-static const char shell_usage[] =
-
-       "sh [FILE]...\n\n" "The BusyBox command interpreter (shell).\n\n";
-
+/* Table of forking built-in functions (things that fork cannot change global
+ * variables in the parent process, such as the current working directory) */
+static struct builtInCommand bltins_forking[] = {
+       {"env", "Print all environment variables", builtin_env},
+       {"pwd", "Print current directory", builtin_pwd},
+       {"help", "List shell built-in commands", builtin_help},
+       {NULL, NULL, NULL}
+};
 
-static char cwd[1024];
 static char *prompt = "# ";
+static char *cwd;
+static char *local_pending_command = NULL;
+static char *promptStr = NULL;
+static struct jobSet jobList = { NULL, NULL };
+static int argc;
+static char **argv;
+#ifdef BB_FEATURE_SH_ENVIRONMENT
+static int lastBgPid=-1;
+static int lastReturnCode=-1;
+static int showXtrace=FALSE;
+#endif
+       
 
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
-void win_changed(int sig)
+void win_changed(int junk)
 {
-       struct winsize win = { 0, 0 };
+       struct winsize win = { 0, 0, 0, 0 };
        ioctl(0, TIOCGWINSZ, &win);
        if (win.ws_col > 0) {
                cmdedit_setwidth( win.ws_col - 1);
@@ -146,7 +193,7 @@ void win_changed(int sig)
 
 
 /* built-in 'cd <path>' handler */
-static int shell_cd(struct job *cmd, struct jobSet *junk)
+static int builtin_cd(struct job *cmd, struct jobSet *junk)
 {
        char *newdir;
 
@@ -158,13 +205,13 @@ static int shell_cd(struct job *cmd, struct jobSet *junk)
                printf("cd: %s: %s\n", newdir, strerror(errno));
                return FALSE;
        }
-       getcwd(cwd, sizeof(cwd));
+       getcwd(cwd, sizeof(char)*MAX_LINE);
 
        return TRUE;
 }
 
 /* built-in 'env' handler */
-static int shell_env(struct job *dummy, struct jobSet *junk)
+static int builtin_env(struct job *dummy, struct jobSet *junk)
 {
        char **e;
 
@@ -174,30 +221,42 @@ static int shell_env(struct job *dummy, struct jobSet *junk)
        return (0);
 }
 
+/* built-in 'exec' handler */
+static int builtin_exec(struct job *cmd, struct jobSet *junk)
+{
+       if (cmd->progs[0].argv[1])
+       {
+               cmd->progs[0].argv++;
+               execvp(cmd->progs[0].argv[0], cmd->progs[0].argv);
+               fatalError("Exec to %s failed: %s\n", cmd->progs[0].argv[0],
+                               strerror(errno));
+       }
+       return TRUE;
+}
+
 /* built-in 'exit' handler */
-static int shell_exit(struct job *cmd, struct jobSet *junk)
+static int builtin_exit(struct job *cmd, struct jobSet *junk)
 {
        if (!cmd->progs[0].argv[1] == 1)
                exit TRUE;
 
-       else
-               exit(atoi(cmd->progs[0].argv[1]));
+       exit (atoi(cmd->progs[0].argv[1]));
 }
 
 /* built-in 'fg' and 'bg' handler */
-static int shell_fg_bg(struct job *cmd, struct jobSet *jobList)
+static int builtin_fg_bg(struct job *cmd, struct jobSet *jobList)
 {
        int i, jobNum;
        struct job *job=NULL;
 
        if (!jobList->head) {
                if (!cmd->progs[0].argv[1] || cmd->progs[0].argv[2]) {
-                       fprintf(stderr, "%s: exactly one argument is expected\n",
+                       errorMsg("%s: exactly one argument is expected\n",
                                        cmd->progs[0].argv[0]);
                        return FALSE;
                }
                if (sscanf(cmd->progs[0].argv[1], "%%%d", &jobNum) != 1) {
-                       fprintf(stderr, "%s: bad argument '%s'\n",
+                       errorMsg("%s: bad argument '%s'\n",
                                        cmd->progs[0].argv[0], cmd->progs[0].argv[1]);
                        return FALSE;
                        for (job = jobList->head; job; job = job->next) {
@@ -211,15 +270,16 @@ static int shell_fg_bg(struct job *cmd, struct jobSet *jobList)
        }
 
        if (!job) {
-               fprintf(stderr, "%s: unknown job %d\n",
+               errorMsg("%s: unknown job %d\n",
                                cmd->progs[0].argv[0], jobNum);
                return FALSE;
        }
 
        if (*cmd->progs[0].argv[0] == 'f') {
                /* Make this job the foreground job */
-               if (tcsetpgrp(0, job->pgrp))
-                       perror("tcsetpgrp");
+               /* suppress messages when run from /linuxrc mag@sysgo.de */
+               if (tcsetpgrp(0, job->pgrp) && errno != ENOTTY)
+                       perror("tcsetpgrp"); 
                jobList->fg = job;
        }
 
@@ -235,13 +295,20 @@ static int shell_fg_bg(struct job *cmd, struct jobSet *jobList)
 }
 
 /* built-in 'help' handler */
-static int shell_help(struct job *cmd, struct jobSet *junk)
+static int builtin_help(struct job *dummy, struct jobSet *junk)
 {
        struct builtInCommand *x;
 
        fprintf(stdout, "\nBuilt-in commands:\n");
        fprintf(stdout, "-------------------\n");
        for (x = bltins; x->cmd; x++) {
+               if (x->descr==NULL)
+                       continue;
+               fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
+       }
+       for (x = bltins_forking; x->cmd; x++) {
+               if (x->descr==NULL)
+                       continue;
                fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
        }
        fprintf(stdout, "\n\n");
@@ -249,7 +316,7 @@ static int shell_help(struct job *cmd, struct jobSet *junk)
 }
 
 /* built-in 'jobs' handler */
-static int shell_jobs(struct job *dummy, struct jobSet *jobList)
+static int builtin_jobs(struct job *dummy, struct jobSet *jobList)
 {
        struct job *job;
        char *statusString;
@@ -267,20 +334,20 @@ static int shell_jobs(struct job *dummy, struct jobSet *jobList)
 
 
 /* built-in 'pwd' handler */
-static int shell_pwd(struct job *dummy, struct jobSet *junk)
+static int builtin_pwd(struct job *dummy, struct jobSet *junk)
 {
-       getcwd(cwd, sizeof(cwd));
+       getcwd(cwd, sizeof(char)*MAX_LINE);
        fprintf(stdout, "%s\n", cwd);
        return TRUE;
 }
 
 /* built-in 'export VAR=value' handler */
-static int shell_export(struct job *cmd, struct jobSet *junk)
+static int builtin_export(struct job *cmd, struct jobSet *junk)
 {
        int res;
 
        if (!cmd->progs[0].argv[1] == 1) {
-               return (shell_env(cmd, junk));
+               return (builtin_env(cmd, junk));
        }
        res = putenv(cmd->progs[0].argv[1]);
        if (res)
@@ -288,8 +355,150 @@ static int shell_export(struct job *cmd, struct jobSet *junk)
        return (res);
 }
 
+/* built-in 'read VAR' handler */
+static int builtin_read(struct job *cmd, struct jobSet *junk)
+{
+       int res = 0, len, newlen;
+       char *s;
+       char string[MAX_READ];
+
+       if (cmd->progs[0].argv[1]) {
+               /* argument (VAR) given: put "VAR=" into buffer */
+               strcpy(string, cmd->progs[0].argv[1]);
+               len = strlen(string);
+               string[len++] = '=';
+               string[len]   = '\0';
+               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);
+               if (res)
+                       fprintf(stdout, "read: %s\n", strerror(errno));
+       }
+       else
+               fgets(string, sizeof(string), stdin);
+
+       return (res);
+}
+
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+/* Built-in handler for 'if' commands */
+static int builtin_if(struct job *cmd, struct jobSet *jobList)
+{
+       int status;
+       char* charptr1=cmd->text+3; /* skip over the leading 'if ' */
+
+       /* Now run the 'if' command */
+       status=strlen(charptr1);
+       local_pending_command = xmalloc(status+1);
+       strncpy(local_pending_command, charptr1, status); 
+       local_pending_command[status]='\0';
+#ifdef DEBUG_SHELL
+       fprintf(stderr, "'if' now testing '%s'\n", local_pending_command);
+#endif
+       status = busy_loop(NULL); /* Frees local_pending_command */
+#ifdef DEBUG_SHELL
+       fprintf(stderr, "if test returned ");
+#endif
+       if (status == 0) {
+#ifdef DEBUG_SHELL
+               fprintf(stderr, "TRUE\n");
+#endif
+               cmd->jobContext |= IF_TRUE_CONTEXT;
+       } else {
+#ifdef DEBUG_SHELL
+               fprintf(stderr, "FALSE\n");
+#endif
+               cmd->jobContext |= IF_FALSE_CONTEXT;
+       }
+
+       return status;
+}
+
+/* Built-in handler for 'then' (part of the 'if' command) */
+static int builtin_then(struct job *cmd, struct jobSet *junk)
+{
+       int status;
+       char* charptr1=cmd->text+5; /* skip over the leading 'then ' */
+
+       if (! (cmd->jobContext & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
+               errorMsg("unexpected token `then'\n");
+               return FALSE;
+       }
+       /* If the if result was FALSE, skip the 'then' stuff */
+       if (cmd->jobContext & IF_FALSE_CONTEXT) {
+               return TRUE;
+       }
+
+       cmd->jobContext |= THEN_EXP_CONTEXT;
+       //printf("Hit an then -- jobContext=%d\n", cmd->jobContext);
+
+       /* Now run the 'then' command */
+       status=strlen(charptr1);
+       local_pending_command = xmalloc(status+1);
+       strncpy(local_pending_command, charptr1, status); 
+       local_pending_command[status]='\0';
+#ifdef DEBUG_SHELL
+       fprintf(stderr, "'then' now running '%s'\n", charptr1);
+#endif
+       return( busy_loop(NULL));
+}
+
+/* Built-in handler for 'else' (part of the 'if' command) */
+static int builtin_else(struct job *cmd, struct jobSet *junk)
+{
+       int status;
+       char* charptr1=cmd->text+5; /* skip over the leading 'else ' */
+
+       if (! (cmd->jobContext & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
+               errorMsg("unexpected token `else'\n");
+               return FALSE;
+       }
+       /* If the if result was TRUE, skip the 'else' stuff */
+       if (cmd->jobContext & IF_TRUE_CONTEXT) {
+               return TRUE;
+       }
+
+       cmd->jobContext |= ELSE_EXP_CONTEXT;
+       //printf("Hit an else -- jobContext=%d\n", cmd->jobContext);
+
+       /* Now run the 'else' command */
+       status=strlen(charptr1);
+       local_pending_command = xmalloc(status+1);
+       strncpy(local_pending_command, charptr1, status); 
+       local_pending_command[status]='\0';
+#ifdef DEBUG_SHELL
+       fprintf(stderr, "'else' now running '%s'\n", charptr1);
+#endif
+       return( busy_loop(NULL));
+}
+
+/* Built-in handler for 'fi' (part of the 'if' command) */
+static int builtin_fi(struct job *cmd, struct jobSet *junk)
+{
+       if (! (cmd->jobContext & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
+               errorMsg("unexpected token `fi'\n");
+               return FALSE;
+       }
+       /* Clear out the if and then context bits */
+       cmd->jobContext &= ~(IF_TRUE_CONTEXT|IF_FALSE_CONTEXT|THEN_EXP_CONTEXT|ELSE_EXP_CONTEXT);
+#ifdef DEBUG_SHELL
+       fprintf(stderr, "Hit an fi   -- jobContext=%d\n", cmd->jobContext);
+#endif
+       return TRUE;
+}
+#endif
+
 /* Built-in '.' handler (read-in and execute commands from file) */
-static int shell_source(struct job *cmd, struct jobSet *junk)
+static int builtin_source(struct job *cmd, struct jobSet *junk)
 {
        FILE *input;
        int status;
@@ -306,11 +515,12 @@ static int shell_source(struct job *cmd, struct jobSet *junk)
 
        /* Now run the file */
        status = busy_loop(input);
+       fclose(input);
        return (status);
 }
 
 /* built-in 'unset VAR' handler */
-static int shell_unset(struct job *cmd, struct jobSet *junk)
+static int builtin_unset(struct job *cmd, struct jobSet *junk)
 {
        if (!cmd->progs[0].argv[1] == 1) {
                fprintf(stdout, "unset: parameter required.\n");
@@ -336,6 +546,7 @@ static void freeJob(struct job *cmd)
        if (cmd->text)
                free(cmd->text);
        free(cmd->cmdBuf);
+       memset(cmd, 0, sizeof(struct job));
 }
 
 /* remove a job from the jobList */
@@ -374,6 +585,10 @@ static void checkJobs(struct jobSet *jobList)
                                break;
                }
 
+               /* This happens on backticked commands */
+               if(job==NULL)
+                       return;
+
                if (WIFEXITED(status) || WIFSIGNALED(status)) {
                        /* child exited */
                        job->runningProgs--;
@@ -399,18 +614,78 @@ static void checkJobs(struct jobSet *jobList)
                perror("waitpid");
 }
 
+static int setupRedirections(struct childProgram *prog)
+{
+       int i;
+       int openfd;
+       int mode = O_RDONLY;
+       struct redirectionSpecifier *redir = prog->redirections;
+
+       for (i = 0; i < prog->numRedirections; i++, redir++) {
+               switch (redir->type) {
+               case REDIRECT_INPUT:
+                       mode = O_RDONLY;
+                       break;
+               case REDIRECT_OVERWRITE:
+                       mode = O_WRONLY | O_CREAT | O_TRUNC;
+                       break;
+               case REDIRECT_APPEND:
+                       mode = O_WRONLY | O_CREAT | O_APPEND;
+                       break;
+               }
+
+               openfd = open(redir->filename, mode, 0666);
+               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!) */
+                       errorMsg("error opening %s: %s\n", redir->filename,
+                                       strerror(errno));
+                       return 1;
+               }
+
+               if (openfd != redir->fd) {
+                       dup2(openfd, redir->fd);
+                       close(openfd);
+               }
+       }
+
+       return 0;
+}
+
+
 static int getCommand(FILE * source, char *command)
 {
+       if (source == NULL) {
+               if (local_pending_command) {
+                       /* a command specified (-c option): return it & mark it done */
+                       strcpy(command, local_pending_command);
+                       free(local_pending_command);
+                       local_pending_command = NULL;
+                       return 0;
+               }
+               return 1;
+       }
+
        if (source == stdin) {
 #ifdef BB_FEATURE_SH_COMMAND_EDITING
                int len;
-               char *promptStr;
+
+               /*
+               ** enable command line editing only while a command line
+               ** is actually being read; otherwise, we'll end up bequeathing
+               ** atexit() handlers and other unwanted stuff to our
+               ** child processes (rob@sysgo.de)
+               */
+               cmdedit_init();
+               signal(SIGWINCH, win_changed);
                len=fprintf(stdout, "%s %s", cwd, prompt);
                fflush(stdout);
-               promptStr=(char*)malloc(sizeof(char)*(len+1));
+               promptStr=(char*)xmalloc(sizeof(char)*(len+1));
                sprintf(promptStr, "%s %s", cwd, prompt);
                cmdedit_read_input(promptStr, command);
                free( promptStr);
+               cmdedit_terminate();
+               signal(SIGWINCH, SIG_DFL);
                return 0;
 #else
                fprintf(stdout, "%s %s", cwd, prompt);
@@ -430,17 +705,40 @@ static int getCommand(FILE * source, char *command)
        return 0;
 }
 
+#ifdef BB_FEATURE_SH_ENVIRONMENT
+#define __MAX_INT_CHARS 7
+static char* itoa(register int i)
+{
+       static char a[__MAX_INT_CHARS];
+       register char *b = a + sizeof(a) - 1;
+       int   sign = (i < 0);
+
+       if (sign)
+               i = -i;
+       *b = 0;
+       do
+       {
+               *--b = '0' + (i % 10);
+               i /= 10;
+       }
+       while (i);
+       if (sign)
+               *--b = '-';
+       return b;
+}
+#endif
+
 static void globLastArgument(struct childProgram *prog, int *argcPtr,
                                                         int *argcAllocedPtr)
 {
-       int argc = *argcPtr;
+       int argc_l = *argcPtr;
        int argcAlloced = *argcAllocedPtr;
        int rc;
        int flags;
        int i;
-       char *src, *dst;
+       char *src, *dst, *var;
 
-       if (argc > 1) {                         /* cmd->globResult is already initialized */
+       if (argc_l > 1) {                               /* cmd->globResult is already initialized */
                flags = GLOB_APPEND;
                i = prog->globResult.gl_pathc;
        } else {
@@ -448,34 +746,83 @@ static void globLastArgument(struct childProgram *prog, int *argcPtr,
                flags = 0;
                i = 0;
        }
+       /* do shell variable substitution */
+       if(*prog->argv[argc_l - 1] == '$') {
+               if ((var = getenv(prog->argv[argc_l - 1] + 1))) {
+                       prog->argv[argc_l - 1] = var;
+               } 
+#ifdef BB_FEATURE_SH_ENVIRONMENT
+               else {
+                       switch(*(prog->argv[argc_l - 1] + 1)) {
+                               case '?':
+                                       prog->argv[argc_l - 1] = itoa(lastReturnCode);
+                                       break;
+                               case '$':
+                                       prog->argv[argc_l - 1] = itoa(getpid());
+                                       break;
+                               case '#':
+                                       prog->argv[argc_l - 1] = itoa(argc-1);
+                                       break;
+                               case '!':
+                                       if (lastBgPid==-1)
+                                               *(prog->argv[argc_l - 1])='\0';
+                                       else
+                                               prog->argv[argc_l - 1] = itoa(lastBgPid);
+                                       break;
+                               case '0':case '1':case '2':case '3':case '4':
+                               case '5':case '6':case '7':case '8':case '9':
+                                       {
+                                               int index=*(prog->argv[argc_l - 1] + 1)-48;
+                                               if (index >= argc) {
+                                                       *(prog->argv[argc_l - 1])='\0';
+                                               } else {
+                                                       prog->argv[argc_l - 1] = argv[index];
+                                               }
+                                       }
+                                       break;
+                       }
+               }
+#endif
+       }
 
-       rc = glob(prog->argv[argc - 1], flags, NULL, &prog->globResult);
-       if (rc == GLOB_NOSPACE) {
-               fprintf(stderr, "out of space during glob operation\n");
-               return;
-       } else if (rc == GLOB_NOMATCH ||
+       if (strpbrk(prog->argv[argc_l - 1],"*[]?")!= NULL){
+               rc = glob(prog->argv[argc_l - 1], flags, NULL, &prog->globResult);
+               if (rc == GLOB_NOSPACE) {
+                       errorMsg("out of space during glob operation\n");
+                       return;
+               } else if (rc == GLOB_NOMATCH ||
                           (!rc && (prog->globResult.gl_pathc - i) == 1 &&
-                               !strcmp(prog->argv[argc - 1],
-                                               prog->globResult.gl_pathv[i]))) {
-               /* we need to remove whatever \ quoting is still present */
-               src = dst = prog->argv[argc - 1];
-               while (*src) {
-                       if (*src != '\\')
-                               *dst++ = *src;
-                       src++;
+                               strcmp(prog->argv[argc_l - 1],
+                                               prog->globResult.gl_pathv[i]) == 0)) {
+                       /* we need to remove whatever \ quoting is still present */
+                       src = dst = prog->argv[argc_l - 1];
+                       while (*src) {
+                               if (*src != '\\')
+                                       *dst++ = *src;
+                               src++;
+                       }
+                       *dst = '\0';
+               } else if (!rc) {
+                       argcAlloced += (prog->globResult.gl_pathc - i);
+                       prog->argv = xrealloc(prog->argv, argcAlloced * sizeof(*prog->argv));
+                       memcpy(prog->argv + (argc_l - 1), prog->globResult.gl_pathv + i,
+                                  sizeof(*(prog->argv)) * (prog->globResult.gl_pathc - i));
+                       argc_l += (prog->globResult.gl_pathc - i - 1);
                }
-               *dst = '\0';
-       } else if (!rc) {
-               argcAlloced += (prog->globResult.gl_pathc - i);
-               prog->argv =
-                       realloc(prog->argv, argcAlloced * sizeof(*prog->argv));
-               memcpy(prog->argv + (argc - 1), prog->globResult.gl_pathv + i,
-                          sizeof(*(prog->argv)) * (prog->globResult.gl_pathc - i));
-               argc += (prog->globResult.gl_pathc - i - 1);
+       }else{
+                       src = dst = prog->argv[argc_l - 1];
+                       while (*src) {
+                               if (*src != '\\')
+                                       *dst++ = *src;
+                               src++;
+                       }
+                       *dst = '\0';
+                       prog->globResult.gl_pathc=0;
+                       if (flags==0)
+                               prog->globResult.gl_pathv=NULL;
        }
-
        *argcAllocedPtr = argcAlloced;
-       *argcPtr = argc;
+       *argcPtr = argc_l;
 }
 
 /* Return cmd->numProgs as 0 if no command is present (e.g. an empty
@@ -483,12 +830,12 @@ static void globLastArgument(struct childProgram *prog, int *argcPtr,
    the beginning of the next command (if the original command had more 
    then one job associated with it) or NULL if no more commands are 
    present. */
-static int parseCommand(char **commandPtr, struct job *job, int *isBg)
+static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobList, int *inBg)
 {
        char *command;
        char *returnCommand = NULL;
        char *src, *buf, *chptr;
-       int argc = 0;
+       int argc_l = 0;
        int done = 0;
        int argvAlloced;
        int i;
@@ -502,22 +849,22 @@ static int parseCommand(char **commandPtr, struct job *job, int *isBg)
 
        /* this handles empty lines or leading '#' characters */
        if (!**commandPtr || (**commandPtr == '#')) {
-               job->numProgs = 0;
-               *commandPtr = NULL;
+               job->numProgs=0;
                return 0;
        }
 
-       *isBg = 0;
+       *inBg = 0;
        job->numProgs = 1;
-       job->progs = malloc(sizeof(*job->progs));
+       job->progs = xmalloc(sizeof(*job->progs));
 
        /* We set the argv elements to point inside of this string. The 
-          memory is freed by freeJob(). 
+          memory is freed by freeJob(). Allocate twice the original
+          length in case we need to quote every single character.
 
           Getting clean memory relieves us of the task of NULL 
           terminating things and makes the rest of this look a bit 
           cleaner (though it is, admittedly, a tad less efficient) */
-       job->cmdBuf = command = calloc(1, strlen(*commandPtr) + 1);
+       job->cmdBuf = command = xcalloc(2*strlen(*commandPtr) + 1, sizeof(char));
        job->text = NULL;
 
        prog = job->progs;
@@ -527,7 +874,7 @@ static int parseCommand(char **commandPtr, struct job *job, int *isBg)
        prog->isStopped = 0;
 
        argvAlloced = 5;
-       prog->argv = malloc(sizeof(*prog->argv) * argvAlloced);
+       prog->argv = xmalloc(sizeof(*prog->argv) * argvAlloced);
        prog->argv[0] = job->cmdBuf;
 
        buf = command;
@@ -539,7 +886,7 @@ static int parseCommand(char **commandPtr, struct job *job, int *isBg)
                        if (*src == '\\') {
                                src++;
                                if (!*src) {
-                                       fprintf(stderr, "character expected after \\\n");
+                                       errorMsg("character expected after \\\n");
                                        freeJob(job);
                                        return 1;
                                }
@@ -551,18 +898,17 @@ static int parseCommand(char **commandPtr, struct job *job, int *isBg)
                                           *src == ']') *buf++ = '\\';
                        *buf++ = *src;
                } else if (isspace(*src)) {
-                       if (*prog->argv[argc]) {
-                               buf++, argc++;
+                       if (*prog->argv[argc_l]) {
+                               buf++, argc_l++;
                                /* +1 here leaves room for the NULL which ends argv */
-                               if ((argc + 1) == argvAlloced) {
+                               if ((argc_l + 1) == argvAlloced) {
                                        argvAlloced += 5;
-                                       prog->argv = realloc(prog->argv,
-                                                                                sizeof(*prog->argv) *
-                                                                                argvAlloced);
+                                       prog->argv = xrealloc(prog->argv,
+                                                                                 sizeof(*prog->argv) *
+                                                                                 argvAlloced);
                                }
-                               prog->argv[argc] = buf;
-
-                               globLastArgument(prog, &argc, &argvAlloced);
+                               globLastArgument(prog, &argc_l, &argvAlloced);
+                               prog->argv[argc_l] = buf;
                        }
                } else
                        switch (*src) {
@@ -572,26 +918,30 @@ static int parseCommand(char **commandPtr, struct job *job, int *isBg)
                                break;
 
                        case '#':                       /* comment */
-                               done = 1;
+                               if (*(src-1)== '$')
+                                       *buf++ = *src;
+                               else
+                                       done = 1;
                                break;
 
                        case '>':                       /* redirections */
                        case '<':
                                i = prog->numRedirections++;
-                               prog->redirections = realloc(prog->redirections,
-                                                                                        sizeof(*prog->redirections) *
-                                                                                        (i + 1));
+                               prog->redirections = xrealloc(prog->redirections,
+                                                                                         sizeof(*prog->redirections) *
+                                                                                         (i + 1));
 
                                prog->redirections[i].fd = -1;
-                               if (buf != prog->argv[argc]) {
+                               if (buf != prog->argv[argc_l]) {
                                        /* the stuff before this character may be the file number 
                                           being redirected */
                                        prog->redirections[i].fd =
-                                               strtol(prog->argv[argc], &chptr, 10);
+                                               strtol(prog->argv[argc_l], &chptr, 10);
 
-                                       if (*chptr && *prog->argv[argc]) {
-                                               buf++, argc++;
-                                               globLastArgument(prog, &argc, &argvAlloced);
+                                       if (*chptr && *prog->argv[argc_l]) {
+                                               buf++, argc_l++;
+                                               globLastArgument(prog, &argc_l, &argvAlloced);
+                                               prog->argv[argc_l] = buf;
                                        }
                                }
 
@@ -618,8 +968,9 @@ static int parseCommand(char **commandPtr, struct job *job, int *isBg)
                                        chptr++;
 
                                if (!*chptr) {
-                                       fprintf(stderr, "file name expected after %c\n", *src);
+                                       errorMsg("file name expected after %c\n", *src);
                                        freeJob(job);
+                                       job->numProgs=0;
                                        return 1;
                                }
 
@@ -628,32 +979,34 @@ static int parseCommand(char **commandPtr, struct job *job, int *isBg)
                                        *buf++ = *chptr++;
 
                                src = chptr - 1;        /* we src++ later */
-                               prog->argv[argc] = ++buf;
+                               prog->argv[argc_l] = ++buf;
                                break;
 
                        case '|':                       /* pipe */
                                /* finish this command */
-                               if (*prog->argv[argc])
-                                       argc++;
-                               if (!argc) {
-                                       fprintf(stderr, "empty command in pipe\n");
+                               if (*prog->argv[argc_l])
+                                       argc_l++;
+                               if (!argc_l) {
+                                       errorMsg("empty command in pipe\n");
                                        freeJob(job);
+                                       job->numProgs=0;
                                        return 1;
                                }
-                               prog->argv[argc] = NULL;
+                               prog->argv[argc_l] = NULL;
 
                                /* and start the next */
                                job->numProgs++;
-                               job->progs = realloc(job->progs,
-                                                                        sizeof(*job->progs) * job->numProgs);
+                               job->progs = xrealloc(job->progs,
+                                                                         sizeof(*job->progs) * job->numProgs);
                                prog = job->progs + (job->numProgs - 1);
                                prog->numRedirections = 0;
                                prog->redirections = NULL;
                                prog->freeGlob = 0;
-                               argc = 0;
+                               prog->isStopped = 0;
+                               argc_l = 0;
 
                                argvAlloced = 5;
-                               prog->argv = malloc(sizeof(*prog->argv) * argvAlloced);
+                               prog->argv = xmalloc(sizeof(*prog->argv) * argvAlloced);
                                prog->argv[0] = ++buf;
 
                                src++;
@@ -661,7 +1014,9 @@ static int parseCommand(char **commandPtr, struct job *job, int *isBg)
                                        src++;
 
                                if (!*src) {
-                                       fprintf(stderr, "empty command in pipe\n");
+                                       errorMsg("empty command in pipe\n");
+                                       freeJob(job);
+                                       job->numProgs=0;
                                        return 1;
                                }
                                src--;                  /* we'll ++ it at the end of the loop */
@@ -669,17 +1024,88 @@ static int parseCommand(char **commandPtr, struct job *job, int *isBg)
                                break;
 
                        case '&':                       /* background */
-                               *isBg = 1;
+                               *inBg = 1;
                        case ';':                       /* multiple commands */
                                done = 1;
                                returnCommand = *commandPtr + (src - *commandPtr) + 1;
                                break;
 
+#ifdef BB_FEATURE_SH_BACKTICKS
+                       case '`':
+                               /* Exec a backtick-ed command */
+                               {
+                                       char* charptr1=NULL, *charptr2;
+                                       char* ptr=NULL;
+                                       struct job *newJob;
+                                       struct jobSet njobList = { NULL, NULL };
+                                       int pipefd[2];
+                                       int size;
+
+                                       ptr=strchr(++src, '`');
+                                       if (ptr==NULL) {
+                                               fprintf(stderr, "Unmatched '`' in command\n");
+                                               freeJob(job);
+                                               return 1;
+                                       }
+
+                                       /* Make some space to hold just the backticked command */
+                                       charptr1 = charptr2 = xmalloc(1+ptr-src);
+                                       memcpy(charptr1, src, ptr-src);
+                                       charptr1[ptr-src] = '\0';
+                                       newJob = xmalloc(sizeof(struct job));
+                                       /* Now parse and run the backticked command */
+                                       if (!parseCommand(&charptr1, newJob, &njobList, inBg) 
+                                                       && newJob->numProgs) {
+                                               pipe(pipefd);
+                                               runCommand(newJob, &njobList, 0, pipefd);
+                                       }
+                                       checkJobs(jobList);
+                                       freeJob(newJob);
+                                       free(charptr2);
+                                       
+                                       /* Make a copy of any stuff left over in the command 
+                                        * line after the second backtick */
+                                       charptr2 = xmalloc(strlen(ptr)+1);
+                                       memcpy(charptr2, ptr+1, strlen(ptr));
+
+
+                                       /* Copy the output from the backtick-ed command into the
+                                        * command line, making extra room as needed  */
+                                       --src;
+                                       charptr1 = xmalloc(BUFSIZ);
+                                       while ( (size=fullRead(pipefd[0], charptr1, BUFSIZ-1)) >0) {
+                                               int newSize=src - *commandPtr + size + 1 + strlen(charptr2);
+                                               if (newSize > BUFSIZ) {
+                                                       *commandPtr=xrealloc(*commandPtr, src - *commandPtr + 
+                                                                       size + 1 + strlen(charptr2));
+                                               }
+                                               memcpy(src, charptr1, size); 
+                                               src+=size;
+                                       }
+                                       free(charptr1);
+                                       close(pipefd[0]);
+                                       if (*(src-1)=='\n')
+                                               --src;
+
+                                       /* Now paste into the *commandPtr all the stuff 
+                                        * leftover after the second backtick */
+                                       memcpy(src, charptr2, strlen(charptr2)+1);
+                                       free(charptr2);
+
+                                       /* Now recursively call parseCommand to deal with the new
+                                        * and improved version of the command line with the backtick
+                                        * results expanded in place... */
+                                       freeJob(job);
+                                       return(parseCommand(commandPtr, job, jobList, inBg));
+                               }
+                               break;
+#endif // BB_FEATURE_SH_BACKTICKS
+
                        case '\\':
                                src++;
                                if (!*src) {
+                                       errorMsg("character expected after \\\n");
                                        freeJob(job);
-                                       fprintf(stderr, "character expected after \\\n");
                                        return 1;
                                }
                                if (*src == '*' || *src == '[' || *src == ']'
@@ -692,60 +1118,79 @@ static int parseCommand(char **commandPtr, struct job *job, int *isBg)
                src++;
        }
 
-       if (*prog->argv[argc]) {
-               argc++;
-               globLastArgument(prog, &argc, &argvAlloced);
+       if (*prog->argv[argc_l]) {
+               argc_l++;
+               globLastArgument(prog, &argc_l, &argvAlloced);
        }
-       if (!argc) {
+       if (!argc_l) {
                freeJob(job);
                return 0;
        }
-       prog->argv[argc] = NULL;
+       prog->argv[argc_l] = NULL;
 
        if (!returnCommand) {
-               job->text = malloc(strlen(*commandPtr) + 1);
+               job->text = xmalloc(strlen(*commandPtr) + 1);
                strcpy(job->text, *commandPtr);
        } else {
                /* This leaves any trailing spaces, which is a bit sloppy */
                count = returnCommand - *commandPtr;
-               job->text = malloc(count + 1);
+               job->text = xmalloc(count + 1);
                strncpy(job->text, *commandPtr, count);
                job->text[count] = '\0';
        }
 
        *commandPtr = returnCommand;
-
+       
        return 0;
 }
 
-static int runCommand(struct job newJob, struct jobSet *jobList, int inBg)
+static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int outPipe[2])
 {
-       struct job *job;
+       struct job *theJob;
        int i;
        int nextin, nextout;
        int pipefds[2];                         /* pipefd[0] is for reading */
        struct builtInCommand *x;
-
-       /* handle built-ins here -- we don't fork() so we can't background
-          these very easily */
-       for (x = bltins; x->cmd; x++) {
-               if (!strcmp(newJob.progs[0].argv[0], x->cmd)) {
-                       return (x->function(&newJob, jobList));
-               }
-       }
+#ifdef BB_FEATURE_SH_STANDALONE_SHELL
+       struct BB_applet search_applet, *applet;
+#endif
 
        nextin = 0, nextout = 1;
-       for (i = 0; i < newJob.numProgs; i++) {
-               if ((i + 1) < newJob.numProgs) {
+       for (i = 0; i < newJob->numProgs; i++) {
+               if ((i + 1) < newJob->numProgs) {
                        pipe(pipefds);
                        nextout = pipefds[1];
                } else {
-                       nextout = 1;
+                       if (outPipe[1]!=-1) {
+                               nextout = outPipe[1];
+                       } else {
+                               nextout = 1;
+                       }
                }
 
-               if (!(newJob.progs[i].pid = fork())) {
+#ifdef BB_FEATURE_SH_ENVIRONMENT
+               if (showXtrace==TRUE) {
+                       int j;
+                       fprintf(stderr, "+ ");
+                       for (j = 0; newJob->progs[i].argv[j]; j++)
+                               fprintf(stderr, "%s ", newJob->progs[i].argv[j]);
+                       fprintf(stderr, "\n");
+               }
+#endif
+
+               /* Check if the command matches any non-forking builtins */
+               for (x = bltins; x->cmd; x++) {
+                       if (strcmp(newJob->progs[i].argv[0], x->cmd) == 0 ) {
+                               return(x->function(newJob, jobList));
+                       }
+               }
+
+               if (!(newJob->progs[i].pid = fork())) {
                        signal(SIGTTOU, SIG_DFL);
 
+                       if (outPipe[1]!=-1) {
+                               close(outPipe[0]);
+                       }
                        if (nextin != 0) {
                                dup2(nextin, 0);
                                close(nextin);
@@ -753,21 +1198,68 @@ static int runCommand(struct job newJob, struct jobSet *jobList, int inBg)
 
                        if (nextout != 1) {
                                dup2(nextout, 1);
+                               dup2(nextout, 2);
                                close(nextout);
+                               close(pipefds[0]);
                        }
 
                        /* explicit redirections override pipes */
-                       setupRedirections(newJob.progs + i);
+                       setupRedirections(newJob->progs + i);
 
-                       execvp(newJob.progs[i].argv[0], newJob.progs[i].argv);
-                       fatalError("sh: %s: %s\n", newJob.progs[i].argv[0],
-                                          strerror(errno));
+                       /* Check if the command matches any of the other builtins */
+                       for (x = bltins_forking; x->cmd; x++) {
+                               if (strcmp(newJob->progs[i].argv[0], x->cmd) == 0) {
+                                       applet_name=x->cmd;
+                                       exit (x->function(newJob, jobList));
+                               }
+                       }
+#ifdef BB_FEATURE_SH_STANDALONE_SHELL
+                       /* Check if the command matches any busybox internal
+                        * commands ("applets") here.  Following discussions from
+                        * November 2000 on busybox@opensource.lineo.com, don't use
+                        * get_last_path_component().  This way explicit (with
+                        * slashes) filenames will never be interpreted as an
+                        * applet, just like with builtins.  This way the user can
+                        * override an applet with an explicit filename reference.
+                        * The only downside to this change is that an explicit
+                        * /bin/foo invocation fill fork and exec /bin/foo, even if
+                        * /bin/foo is a symlink to busybox.
+                        */
+                       search_applet.name = newJob->progs[i].argv[0];
+
+#ifdef BB_FEATURE_SH_BUILTINS_ALWAYS_WIN
+                       /* If you enable BB_FEATURE_SH_BUILTINS_ALWAYS_WIN, then
+                        * if you run /bin/cat, it will use BusyBox cat even if 
+                        * /bin/cat exists on the filesystem and is _not_ busybox.
+                        * Some systems want this, others do not.  Choose wisely.  :-)
+                        */
+                       search_applet.name = get_last_path_component(search_applet.name);
+#endif
+
+                       /* Do a binary search to find the applet entry given the name. */
+                       applet = bsearch(&search_applet, applets, NUM_APPLETS,
+                                       sizeof(struct BB_applet), applet_name_compare);
+                       if (applet != NULL) {
+                               int argc_l;
+                               char** argv=newJob->progs[i].argv;
+                               for(argc_l=0;*argv!=NULL; argv++, argc_l++);
+                               applet_name=applet->name;
+                               optind = 1;
+                               exit((*(applet->main)) (argc_l, newJob->progs[i].argv));
+                       }
+#endif
+
+                       execvp(newJob->progs[i].argv[0], newJob->progs[i].argv);
+                       fatalError("%s: %s\n", newJob->progs[i].argv[0],
+                                       strerror(errno));
+               }
+               if (outPipe[1]!=-1) {
+                       close(outPipe[1]);
                }
 
                /* put our child in the process group whose leader is the
                   first process in this pipe */
-               setpgid(newJob.progs[i].pid, newJob.progs[0].pid);
-
+               setpgid(newJob->progs[i].pid, newJob->progs[0].pid);
                if (nextin != 0)
                        close(nextin);
                if (nextout != 1)
@@ -778,94 +1270,63 @@ static int runCommand(struct job newJob, struct jobSet *jobList, int inBg)
                nextin = pipefds[0];
        }
 
-       newJob.pgrp = newJob.progs[0].pid;
+       newJob->pgrp = newJob->progs[0].pid;
 
-       /* find the ID for the job to use */
-       newJob.jobId = 1;
-       for (job = jobList->head; job; job = job->next)
-               if (job->jobId >= newJob.jobId)
-                       newJob.jobId = job->jobId + 1;
+       /* find the ID for the theJob to use */
+       newJob->jobId = 1;
+       for (theJob = jobList->head; theJob; theJob = theJob->next)
+               if (theJob->jobId >= newJob->jobId)
+                       newJob->jobId = theJob->jobId + 1;
 
-       /* add the job to the list of running jobs */
+       /* add the theJob to the list of running jobs */
        if (!jobList->head) {
-               job = jobList->head = malloc(sizeof(*job));
+               theJob = jobList->head = xmalloc(sizeof(*theJob));
        } else {
-               for (job = jobList->head; job->next; job = job->next);
-               job->next = malloc(sizeof(*job));
-               job = job->next;
+               for (theJob = jobList->head; theJob->next; theJob = theJob->next);
+               theJob->next = xmalloc(sizeof(*theJob));
+               theJob = theJob->next;
        }
 
-       *job = newJob;
-       job->next = NULL;
-       job->runningProgs = job->numProgs;
-       job->stoppedProgs = 0;
+       *theJob = *newJob;
+       theJob->next = NULL;
+       theJob->runningProgs = theJob->numProgs;
+       theJob->stoppedProgs = 0;
 
        if (inBg) {
-               /* we don't wait for background jobs to return -- append it 
-                  to the list of backgrounded jobs and leave it alone */
-               printf("[%d] %d\n", job->jobId,
-                          newJob.progs[newJob.numProgs - 1].pid);
+               /* we don't wait for background theJobs to return -- append it 
+                  to the list of backgrounded theJobs and leave it alone */
+               printf("[%d] %d\n", theJob->jobId,
+                          newJob->progs[newJob->numProgs - 1].pid);
+#ifdef BB_FEATURE_SH_ENVIRONMENT
+               lastBgPid=newJob->progs[newJob->numProgs - 1].pid;
+#endif
        } else {
-               jobList->fg = job;
+               jobList->fg = theJob;
 
                /* move the new process group into the foreground */
-               if (tcsetpgrp(0, newJob.pgrp))
+               /* suppress messages when run from /linuxrc mag@sysgo.de */
+               if (tcsetpgrp(0, newJob->pgrp) && errno != ENOTTY)
                        perror("tcsetpgrp");
        }
 
        return 0;
 }
 
-static int setupRedirections(struct childProgram *prog)
-{
-       int i;
-       int openfd;
-       int mode = O_RDONLY;
-       struct redirectionSpecifier *redir = prog->redirections;
-
-       for (i = 0; i < prog->numRedirections; i++, redir++) {
-               switch (redir->type) {
-               case REDIRECT_INPUT:
-                       mode = O_RDONLY;
-                       break;
-               case REDIRECT_OVERWRITE:
-                       mode = O_RDWR | O_CREAT | O_TRUNC;
-                       break;
-               case REDIRECT_APPEND:
-                       mode = O_RDWR | O_CREAT | O_APPEND;
-                       break;
-               }
-
-               openfd = open(redir->filename, mode, 0666);
-               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->filename,
-                                       strerror(errno));
-                       return 1;
-               }
-
-               if (openfd != redir->fd) {
-                       dup2(openfd, redir->fd);
-                       close(openfd);
-               }
-       }
-
-       return 0;
-}
-
-
 static int busy_loop(FILE * input)
 {
        char *command;
        char *nextCommand = NULL;
-       struct jobSet jobList = { NULL, NULL };
        struct job newJob;
+       pid_t  parent_pgrp;
        int i;
-       int status;
        int inBg;
+       int status;
+       newJob.jobContext = REGULAR_JOB_CONTEXT;
+
+       /* save current owner of TTY so we can restore it on exit */
+       parent_pgrp = tcgetpgrp(0);
 
-       command = (char *) calloc(BUFSIZ, sizeof(char));
+       command = (char *) xcalloc(BUFSIZ, sizeof(char));
 
        /* don't pay any attention to this signal; it just confuses 
           things and isn't really meant for shells anyway */
@@ -884,15 +1345,21 @@ static int busy_loop(FILE * input)
                                nextCommand = command;
                        }
 
-                       if (!parseCommand(&nextCommand, &newJob, &inBg) &&
+                       if (!parseCommand(&nextCommand, &newJob, &jobList, &inBg) &&
                                newJob.numProgs) {
-                               runCommand(newJob, &jobList, inBg);
+                               int pipefds[2] = {-1,-1};
+                               runCommand(&newJob, &jobList, inBg, pipefds);
+                       }
+                       else {
+                               free(command);
+                               command = (char *) xcalloc(BUFSIZ, sizeof(char));
+                               nextCommand = NULL;
                        }
                } else {
                        /* a job is running in the foreground; wait for it */
                        i = 0;
                        while (!jobList.fg->progs[i].pid ||
-                                  jobList.fg->progs[i].isStopped) i++;
+                                  jobList.fg->progs[i].isStopped == 1) i++;
 
                        waitpid(jobList.fg->progs[i].pid, &status, WUNTRACED);
 
@@ -901,15 +1368,17 @@ static int busy_loop(FILE * input)
                                jobList.fg->runningProgs--;
                                jobList.fg->progs[i].pid = 0;
 
+#ifdef BB_FEATURE_SH_ENVIRONMENT
+                               lastReturnCode=WEXITSTATUS(status);
+#endif
+#if 0
+                               printf("'%s' exited -- return code %d\n", jobList.fg->text, lastReturnCode);
+#endif
                                if (!jobList.fg->runningProgs) {
                                        /* child exited */
 
                                        removeJob(&jobList, jobList.fg);
                                        jobList.fg = NULL;
-
-                                       /* move the shell to the foreground */
-                                       if (tcsetpgrp(0, getpid()))
-                                               perror("tcsetpgrp");
                                }
                        } else {
                                /* the child was stopped */
@@ -925,50 +1394,105 @@ static int busy_loop(FILE * input)
 
                        if (!jobList.fg) {
                                /* move the shell to the foreground */
-                               if (tcsetpgrp(0, getpid()))
-                                       perror("tcsetpgrp");
+                               /* suppress messages when run from /linuxrc mag@sysgo.de */
+                               if (tcsetpgrp(0, getpid()) && errno != ENOTTY)
+                                       perror("tcsetpgrp"); 
                        }
                }
        }
        free(command);
 
+       /* return controlling TTY back to parent process group before exiting */
+       if (tcsetpgrp(0, parent_pgrp))
+               perror("tcsetpgrp");
+
+       /* return exit status if called with "-c" */
+       if (input == NULL && WIFEXITED(status))
+               return WEXITSTATUS(status);
+       
        return 0;
 }
 
 
-int shell_main(int argc, char **argv)
+#ifdef BB_FEATURE_CLEAN_UP
+void free_memory(void)
 {
-       FILE *input = stdin;
-
-       if (argc > 2) {
-               usage(shell_usage);
+       if (promptStr)
+               free(promptStr);
+       if (cwd)
+               free(cwd);
+       if (local_pending_command)
+               free(local_pending_command);
+
+       if (jobList.fg && !jobList.fg->runningProgs) {
+               removeJob(&jobList, jobList.fg);
        }
-       /* initialize the cwd */
-       getcwd(cwd, sizeof(cwd));
-
-#ifdef BB_FEATURE_SH_COMMAND_EDITING
-       cmdedit_init();
-       signal(SIGWINCH, win_changed);
-       win_changed(0);
+}
 #endif
 
+
+int shell_main(int argc_l, char **argv_l)
+{
+       int opt, interactive=FALSE;
+       FILE *input = stdin;
+       argc = argc_l;
+       argv = argv_l;
+
+
        //if (argv[0] && argv[0][0] == '-') {
-       //      shell_source("/etc/profile");
+       //      builtin_source("/etc/profile");
        //}
 
-       if (argc < 2) {
+       while ((opt = getopt(argc_l, argv_l, "cx")) > 0) {
+               switch (opt) {
+                       case 'c':
+                               input = NULL;
+                               if (local_pending_command != 0)
+                                       fatalError("multiple -c arguments\n");
+                               local_pending_command = xstrdup(argv[optind]);
+                               optind++;
+                               argv = argv+optind;
+                               break;
+#ifdef BB_FEATURE_SH_ENVIRONMENT
+                       case 'x':
+                               showXtrace = TRUE;
+                               break;
+#endif
+                       case 'i':
+                               interactive = TRUE;
+                               break;
+                       default:
+                               usage(shell_usage);
+               }
+       }
+       /* A shell is interactive if the `-i' flag was given, or if all of
+        * the following conditions are met:
+        *        no -c command
+        *    no arguments remaining or the -s flag given
+        *    standard input is a terminal
+        *    standard output is a terminal
+        *    Refer to Posix.2, the description of the `sh' utility. */
+       if (interactive==TRUE || ( argv[optind]==NULL && input==stdin && isatty(fileno(stdin)) && isatty(fileno(stdout)))) {
+               //fprintf(stdout, "optind=%d  argv[optind]='%s'\n", optind, argv[optind]);
+               /* Looks like they want an interactive shell */
                fprintf(stdout, "\n\nBusyBox v%s (%s) Built-in shell\n", BB_VER, BB_BT);
                fprintf(stdout, "Enter 'help' for a list of built-in commands.\n\n");
-       } else {
-               if (*argv[1]=='-') {
-                       usage("sh\n\nlash -- the BusyBox LAme SHell (command interpreter)\n");
-               }
-               input = fopen(argv[1], "r");
-               if (!input) {
-                       fatalError("sh: Couldn't open file '%s': %s\n", argv[1],
-                                          strerror(errno));
-               }
+       } else if (local_pending_command==NULL) {
+               //fprintf(stdout, "optind=%d  argv[optind]='%s'\n", optind, argv[optind]);
+               input = xfopen(argv[optind], "r");
        }
 
+       /* initialize the cwd -- this is never freed...*/
+       cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
+       getcwd(cwd, sizeof(char)*MAX_LINE);
+
+#ifdef BB_FEATURE_CLEAN_UP
+       atexit(free_memory);
+#endif
+
+#ifdef BB_FEATURE_SH_COMMAND_EDITING
+       win_changed(0);
+#endif
+
        return (busy_loop(input));
 }