busybox/debianutils/which.c
Denys Vlasenko 49d9e06fba libbb: modify find_executable() to not temporarily write to PATH
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>
2024-10-08 04:03:17 +02:00

71 lines
1.7 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
* Copyright (C) 2006 Gabriel Somlo <somlo at cmu.edu>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config WHICH
//config: bool "which (4 kb)"
//config: default y
//config: help
//config: which is used to find programs in your PATH and
//config: print out their pathnames.
//applet:IF_WHICH(APPLET_NOFORK(which, which, BB_DIR_USR_BIN, BB_SUID_DROP, which))
//kbuild:lib-$(CONFIG_WHICH) += which.o
//usage:#define which_trivial_usage
//usage: "[-a] COMMAND..."
//usage:#define which_full_usage "\n\n"
//usage: "Locate COMMAND\n"
//usage: "\n -a Show all matches"
//usage:
//usage:#define which_example_usage
//usage: "$ which login\n"
//usage: "/bin/login\n"
#include "libbb.h"
int which_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int which_main(int argc UNUSED_PARAM, char **argv)
{
const char *env_path;
int status = 0;
env_path = getenv("PATH");
if (!env_path)
env_path = bb_default_root_path;
getopt32(argv, "^" "a" "\0" "-1"/*at least one arg*/);
argv += optind;
do {
int missing = 1;
/* If file contains a slash don't use PATH */
if (strchr(*argv, '/')) {
if (file_is_executable(*argv)) {
missing = 0;
puts(*argv);
}
} else {
const char *path;
char *p;
path = env_path;
/* NOFORK NB: xmalloc inside find_executable(), must have no allocs above! */
while ((p = find_executable(*argv, &path)) != NULL) {
missing = 0;
puts(p);
free(p);
if (!option_mask32) /* -a not set */
break;
}
}
status |= missing;
} while (*++argv);
return status;
}