projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 2614d1e5 C |
1 | /* exec.c */ |
| 2 | #include <signal.h> | |
| 3 | #include <errno.h> | |
| 4 | #include <setjmp.h> | |
| 5 | #include "rc.h" | |
| 6 | #include "jbwrap.h" | |
| 7 | ||
| 8 | /* | |
| 9 | Takes an argument list and does the appropriate thing (calls a | |
| 10 | builtin, calls a function, etc.) | |
| 11 | */ | |
| 12 | ||
| 13 | extern void exec(List *s, bool parent) { | |
| 14 | char **av, **ev = NULL; | |
| 15 | int pid, stat; | |
| 16 | builtin_t *b; | |
| 17 | char *path = NULL; | |
| 18 | bool didfork, returning, saw_exec, saw_builtin; | |
| 19 | av = list2array(s, dashex); | |
| 20 | saw_builtin = saw_exec = FALSE; | |
| 21 | do { | |
| 22 | if (*av == NULL || isabsolute(*av)) | |
| 23 | b = NULL; | |
| 24 | else if (!saw_builtin && fnlookup(*av) != NULL) | |
| 25 | b = funcall; | |
| 26 | else | |
| 27 | b = isbuiltin(*av); | |
| 28 | ||
| 29 | /* | |
| 30 | a builtin applies only to the immmediately following | |
| 31 | command, e.g., builtin exec echo hi | |
| 32 | */ | |
| 33 | saw_builtin = FALSE; | |
| 34 | ||
| 35 | if (b == b_exec) { | |
| 36 | av++; | |
| 37 | saw_exec = TRUE; | |
| 38 | parent = FALSE; | |
| 39 | } else if (b == b_builtin) { | |
| 40 | av++; | |
| 41 | saw_builtin = TRUE; | |
| 42 | } | |
| 43 | } while (b == b_exec || b == b_builtin); | |
| 44 | if (*av == NULL && saw_exec) { /* do redirs and return on a null exec */ | |
| 45 | doredirs(); | |
| 46 | return; | |
| 47 | } | |
| 48 | /* force an exit on exec with any rc_error, but not for null commands as above */ | |
| 49 | if (saw_exec) | |
| 50 | rc_pid = -1; | |
| 51 | if (b == NULL) { | |
| 52 | path = which(*av, TRUE); | |
| 53 | if (path == NULL && *av != NULL) { /* perform null commands for redirections */ | |
| 54 | set(FALSE); | |
| 55 | redirq = NULL; | |
| 56 | if (parent) | |
| 57 | return; | |
| 58 | rc_exit(1); | |
| 59 | } | |
| 60 | ev = makeenv(); /* environment only needs to be built for execve() */ | |
| 61 | } | |
| 62 | /* | |
| 63 | If parent & the redirq is nonnull, builtin or not it has to fork. | |
| 64 | If the fifoq is nonnull, then it must be emptied at the end so we | |
| 65 | must fork no matter what. | |
| 66 | */ | |
| 67 | if ((parent && (b == NULL || redirq != NULL)) || outstanding_cmdarg()) { | |
| 68 | pid = rc_fork(); | |
| 69 | didfork = TRUE; | |
| 70 | } else { | |
| 71 | pid = 0; | |
| 72 | didfork = FALSE; | |
| 73 | } | |
| 74 | returning = (!didfork && parent); | |
| 75 | switch (pid) { | |
| 76 | case -1: | |
| 77 | uerror("fork"); | |
| 78 | rc_error(NULL); | |
| 79 | /* NOTREACHED */ | |
| 80 | case 0: | |
| 81 | if (!returning) | |
| 82 | setsigdefaults(FALSE); | |
| 83 | pop_cmdarg(FALSE); | |
| 84 | doredirs(); | |
| 85 | ||
| 86 | /* null commands performed for redirections */ | |
| 87 | if (*av == NULL || b != NULL) { | |
| 88 | if (b != NULL) | |
| 89 | (*b)(av); | |
| 90 | if (returning) | |
| 91 | return; | |
| 92 | rc_exit(getstatus()); | |
| 93 | } | |
| 94 | execve(path, (char * const *) av, (char * const *) ev); | |
| 95 | uerror(*av); | |
| 96 | rc_exit(1); | |
| 97 | /* NOTREACHED */ | |
| 98 | default: | |
| 99 | redirq = NULL; | |
| 100 | rc_wait4(pid, &stat, TRUE); | |
| 101 | setstatus(-1, stat); | |
| 102 | if ((stat & 0xff) == 0) | |
| 103 | nl_on_intr = FALSE; | |
| 104 | SIGCHK; | |
| 105 | nl_on_intr = TRUE; | |
| 106 | pop_cmdarg(TRUE); | |
| 107 | } | |
| 108 | } |