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