1 /* vi: set sw=4 ts=4: */
5 * Copyright (C) 2006 Gabriel Somlo <somlo at cmu.edu>
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
11 /* check if path points to an executable file;
15 int FAST_FUNC file_is_executable(const char *name)
18 return (!access(name, X_OK) && !stat(name, &s) && S_ISREG(s.st_mode));
21 /* search (*PATHp) for an executable file;
22 * return allocated string containing full path if found;
23 * PATHp points to the component after the one where it was found
25 * you may call find_executable again with this PATHp to continue
27 * return NULL otherwise; (PATHp is undefined)
28 * in all cases (*PATHp) contents will be trashed (s/:/NUL/).
30 char* FAST_FUNC find_executable(const char *filename, char **PATHp)
32 /* About empty components in $PATH:
33 * http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap08.html
34 * 8.3 Other Environment Variables - PATH
35 * A zero-length prefix is a legacy feature that indicates the current
36 * working directory. It appears as two adjacent colons ( "::" ), as an
37 * initial colon preceding the rest of the list, or as a trailing colon
38 * following the rest of the list.
48 p[0] ? p : ".", /* handle "::" case */
51 if (file_is_executable(p)) {
57 } /* on loop exit p == NULL */
61 /* search $PATH for an executable file;
65 int FAST_FUNC executable_exists(const char *filename)
67 char *path = xstrdup(getenv("PATH"));
69 char *ret = find_executable(filename, &tmp);
75 #if ENABLE_FEATURE_PREFER_APPLETS
76 /* just like the real execvp, but try to launch an applet named 'file' first */
77 int FAST_FUNC BB_EXECVP(const char *file, char *const argv[])
79 if (find_applet_by_name(file) >= 0)
80 execvp(bb_busybox_exec_path, argv);
81 return execvp(file, argv);
85 void FAST_FUNC BB_EXECVP_or_die(char **argv)
87 BB_EXECVP(argv[0], argv);
88 /* SUSv3-mandated exit codes */
89 xfunc_error_retval = (errno == ENOENT) ? 127 : 126;
90 bb_perror_msg_and_die("can't execute '%s'", argv[0]);
93 /* Typical idiom for applets which exec *optional* PROG [ARGS] */
94 void FAST_FUNC exec_prog_or_SHELL(char **argv)
97 BB_EXECVP_or_die(argv);
99 run_shell(getenv("SHELL"), /*login:*/ 1, NULL);