hush/libbb/execable.c

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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 execable_file(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_execable again with this PATHp to continue
* (if it's not NULL).
* return NULL otherwise; (PATHp is undefined)
* in all cases (*PATHp) contents will be trashed (s/:/NUL/).
*/
char* FAST_FUNC find_execable(const char *filename, char **PATHp)
{
char *p, *n;
p = *PATHp;
while (p) {
n = strchr(p, ':');
if (n)
*n++ = '\0';
if (*p != '\0') { /* it's not a PATH="foo::bar" situation */
p = concat_path_file(p, filename);
if (execable_file(p)) {
*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 exists_execable(const char *filename)
{
char *path = xstrdup(getenv("PATH"));
char *tmp = path;
char *ret = find_execable(filename, &tmp);
free(path);
if (ret) {
free(ret);
return 1;
}
return 0;
}
#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
int 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]);
}