blob: 3a1d4ff445e9d94123c1c431d9384e670d67976f
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); |
101 | } |
102 |