[3621] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Utility routines.
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| 4 | *
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| 5 | * Copyright (C) 2006 Gabriel Somlo <somlo at cmu.edu>
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| 6 | *
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| 7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 8 | */
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| 9 |
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| 10 | #include "libbb.h"
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| 11 |
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| 12 | /* check if path points to an executable file;
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| 13 | * return 1 if found;
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| 14 | * return 0 otherwise;
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| 15 | */
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| 16 | int FAST_FUNC file_is_executable(const char *name)
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| 17 | {
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| 18 | struct stat s;
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| 19 | return (!access(name, X_OK) && !stat(name, &s) && S_ISREG(s.st_mode));
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| 20 | }
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| 21 |
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| 22 | /* search (*PATHp) for an executable file;
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| 23 | * return allocated string containing full path if found;
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| 24 | * PATHp points to the component after the one where it was found
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| 25 | * (or NULL),
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| 26 | * you may call find_executable again with this PATHp to continue
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| 27 | * (if it's not NULL).
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| 28 | * return NULL otherwise; (PATHp is undefined)
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| 29 | * in all cases (*PATHp) contents will be trashed (s/:/NUL/).
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| 30 | */
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| 31 | char* FAST_FUNC find_executable(const char *filename, char **PATHp)
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| 32 | {
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| 33 | /* About empty components in $PATH:
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| 34 | * http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap08.html
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| 35 | * 8.3 Other Environment Variables - PATH
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| 36 | * A zero-length prefix is a legacy feature that indicates the current
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| 37 | * working directory. It appears as two adjacent colons ( "::" ), as an
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| 38 | * initial colon preceding the rest of the list, or as a trailing colon
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| 39 | * following the rest of the list.
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| 40 | */
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| 41 | char *p, *n;
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| 42 |
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| 43 | p = *PATHp;
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| 44 | while (p) {
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| 45 | n = strchr(p, ':');
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| 46 | if (n)
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| 47 | *n++ = '\0';
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| 48 | p = concat_path_file(
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| 49 | p[0] ? p : ".", /* handle "::" case */
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| 50 | filename
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| 51 | );
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| 52 | if (file_is_executable(p)) {
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| 53 | *PATHp = n;
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| 54 | return p;
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| 55 | }
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| 56 | free(p);
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| 57 | p = n;
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| 58 | } /* on loop exit p == NULL */
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| 59 | return p;
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| 60 | }
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| 61 |
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| 62 | /* search $PATH for an executable file;
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| 63 | * return 1 if found;
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| 64 | * return 0 otherwise;
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| 65 | */
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| 66 | int FAST_FUNC executable_exists(const char *filename)
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| 67 | {
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| 68 | char *path = xstrdup(getenv("PATH"));
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| 69 | char *tmp = path;
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| 70 | char *ret = find_executable(filename, &tmp);
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| 71 | free(path);
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| 72 | free(ret);
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| 73 | return ret != NULL;
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| 74 | }
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| 75 |
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| 76 | #if ENABLE_FEATURE_PREFER_APPLETS
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| 77 | /* just like the real execvp, but try to launch an applet named 'file' first */
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| 78 | int FAST_FUNC BB_EXECVP(const char *file, char *const argv[])
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| 79 | {
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| 80 | if (find_applet_by_name(file) >= 0)
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| 81 | execvp(bb_busybox_exec_path, argv);
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| 82 | return execvp(file, argv);
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| 83 | }
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| 84 | #endif
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| 85 |
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| 86 | void FAST_FUNC BB_EXECVP_or_die(char **argv)
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| 87 | {
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| 88 | BB_EXECVP(argv[0], argv);
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| 89 | /* SUSv3-mandated exit codes */
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| 90 | xfunc_error_retval = (errno == ENOENT) ? 127 : 126;
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| 91 | bb_perror_msg_and_die("can't execute '%s'", argv[0]);
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| 92 | }
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| 93 |
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| 94 | /* Typical idiom for applets which exec *optional* PROG [ARGS] */
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| 95 | void FAST_FUNC exec_prog_or_SHELL(char **argv)
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| 96 | {
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| 97 | if (argv[0]) {
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| 98 | BB_EXECVP_or_die(argv);
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| 99 | }
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| 100 | run_shell(getenv("SHELL"), /*login:*/ 1, NULL, NULL);
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| 101 | }
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