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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 2006 Gabriel Somlo <somlo at cmu.edu>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
/* check if path points to an executable file;
* return 1 if found;
* return 0 otherwise;
*/
int FAST_FUNC file_is_executable(const char *name)
{
struct stat s;
return (!access(name, X_OK) && !stat(name, &s) && S_ISREG(s.st_mode));
}
/* search (*PATHp) for an executable file;
* return allocated string containing full path if found;
* PATHp points to the component after the one where it was found
* (or NULL),
* you may call find_executable again with this PATHp to continue
* (if it's not NULL).
* return NULL otherwise; (PATHp is undefined)
* in all cases (*PATHp) contents are temporarily modified
* but are restored on return (s/:/NUL/ and back).
*/
char* FAST_FUNC find_executable(const char *filename, char **PATHp)
{
/* About empty components in $PATH:
* http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap08.html
* 8.3 Other Environment Variables - PATH
* A zero-length prefix is a legacy feature that indicates the current
* working directory. It appears as two adjacent colons ( "::" ), as an
* initial colon preceding the rest of the list, or as a trailing colon
* following the rest of the list.
*/
char *p, *n;
p = *PATHp;
while (p) {
int ex;
n = strchr(p, ':');
if (n) *n = '\0';
p = concat_path_file(
p[0] ? p : ".", /* handle "::" case */
filename
);
ex = file_is_executable(p);
if (n) *n++ = ':';
if (ex) {
*PATHp = n;
return p;
}
free(p);
p = n;
} /* on loop exit p == NULL */
return p;
}
/* search $PATH for an executable file;
* return 1 if found;
* return 0 otherwise;
*/
int FAST_FUNC executable_exists(const char *filename)
{
char *path = getenv("PATH");
char *ret = find_executable(filename, &path);
free(ret);
return ret != NULL;
}
#if ENABLE_FEATURE_PREFER_APPLETS
/* just like the real execvp, but try to launch an applet named 'file' first */
int FAST_FUNC BB_EXECVP(const char *file, char *const argv[])
{
if (find_applet_by_name(file) >= 0)
execvp(bb_busybox_exec_path, argv);
return execvp(file, argv);
}
#endif
void FAST_FUNC BB_EXECVP_or_die(char **argv)
{
BB_EXECVP(argv[0], argv);
/* SUSv3-mandated exit codes */
xfunc_error_retval = (errno == ENOENT) ? 127 : 126;
bb_perror_msg_and_die("can't execute '%s'", argv[0]);
}
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