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49d9e06fba
This allows to simplify "which" applet code function old new delta find_executable 93 111 +18 which_main 191 177 -14 builtin_source 316 294 -22 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 1/2 up/down: 18/-36) Total: -18 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
97 lines
2.7 KiB
C
97 lines
2.7 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Utility routines.
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*
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* Copyright (C) 2006 Gabriel Somlo <somlo at cmu.edu>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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#include "libbb.h"
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/* check if path points to an executable file;
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* return 1 if found;
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* return 0 otherwise;
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*/
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int FAST_FUNC file_is_executable(const char *name)
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{
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struct stat s;
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return (!access(name, X_OK) && !stat(name, &s) && S_ISREG(s.st_mode));
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}
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/* search (*PATHp) for an executable file;
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* return allocated string containing full path if found;
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* PATHp points to the component after the one where it was found
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* (or NULL if found in last component),
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* you may call find_executable again with this PATHp to continue
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* return NULL otherwise (PATHp is undefined)
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*/
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char* FAST_FUNC find_executable(const char *name, const char **PATHp)
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{
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/* About empty components in $PATH:
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* http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap08.html
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* 8.3 Other Environment Variables - PATH
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* A zero-length prefix is a legacy feature that indicates the current
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* working directory. It appears as two adjacent colons ( "::" ), as an
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* initial colon preceding the rest of the list, or as a trailing colon
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* following the rest of the list.
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*/
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char *p = (char*) *PATHp;
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if (!p)
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return NULL;
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while (1) {
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const char *end = strchrnul(p, ':');
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int sz = end - p;
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if (sz != 0) {
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p = xasprintf("%.*s/%s", sz, p, name);
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} else {
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/* We have xxx::yyy in $PATH,
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* it means "use current dir" */
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p = xstrdup(name);
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// A bit of discrepancy wrt the path used if file is found here.
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// bash 5.2.15 "type" returns "./NAME".
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// GNU which v2.21 returns "/CUR/DIR/NAME".
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// With -a, both skip over all colons: xxx::::yyy is the same as xxx::yyy,
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// current dir is not tried the second time.
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}
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if (file_is_executable(p)) {
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*PATHp = (*end ? end+1 : NULL);
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return p;
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}
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free(p);
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if (*end == '\0')
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return NULL;
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p = (char *) end + 1;
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}
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}
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/* search $PATH for an executable file;
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* return 1 if found;
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* return 0 otherwise;
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*/
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int FAST_FUNC executable_exists(const char *name)
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{
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const char *path = getenv("PATH");
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char *ret = find_executable(name, &path);
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free(ret);
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return ret != NULL;
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}
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#if ENABLE_FEATURE_PREFER_APPLETS
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/* just like the real execvp, but try to launch an applet named 'file' first */
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int FAST_FUNC BB_EXECVP(const char *file, char *const argv[])
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{
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if (find_applet_by_name(file) >= 0)
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execvp(bb_busybox_exec_path, argv);
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return execvp(file, argv);
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}
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#endif
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void FAST_FUNC BB_EXECVP_or_die(char **argv)
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{
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BB_EXECVP(argv[0], argv);
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/* SUSv3-mandated exit codes */
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xfunc_error_retval = (errno == ENOENT) ? 127 : 126;
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bb_perror_msg_and_die("can't execute '%s'", argv[0]);
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}
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