debianutils/which.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   4  * Copyright (C) 2006 Gabriel Somlo <somlo at cmu.edu>
   5  *
   6  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   7  */
   8 //config:config WHICH
   9 //config:       bool "which (3.8 kb)"
  10 //config:       default y
  11 //config:       help
  12 //config:       which is used to find programs in your PATH and
  13 //config:       print out their pathnames.
  14
  15 //applet:IF_WHICH(APPLET_NOFORK(which, which, BB_DIR_USR_BIN, BB_SUID_DROP, which))
  16
  17 //kbuild:lib-$(CONFIG_WHICH) += which.o
  18
  19 //usage:#define which_trivial_usage
  20 //usage:       "[COMMAND]..."
  21 //usage:#define which_full_usage "\n\n"
  22 //usage:       "Locate a COMMAND"
  23 //usage:
  24 //usage:#define which_example_usage
  25 //usage:       "$ which login\n"
  26 //usage:       "/bin/login\n"
  27
  28 #include "libbb.h"
  29
  30 int which_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  31 int which_main(int argc UNUSED_PARAM, char **argv)
  32 {
  33         char *env_path;
  34         int status = 0;
  35         /* This sizeof(): bb_default_root_path is shorter than BB_PATH_ROOT_PATH */
  36         char buf[sizeof(BB_PATH_ROOT_PATH)];
  37
  38         env_path = getenv("PATH");
  39         if (!env_path)
  40                 /* env_path must be writable, and must not alloc, so... */
  41                 env_path = strcpy(buf, bb_default_root_path);
  42
  43         getopt32(argv, "^" "a" "\0" "-1"/*at least one arg*/);
  44         argv += optind;
  45
  46         do {
  47                 int missing = 1;
  48
  49                 /* If file contains a slash don't use PATH */
  50                 if (strchr(*argv, '/')) {
  51                         if (file_is_executable(*argv)) {
  52                                 missing = 0;
  53                                 puts(*argv);
  54                         }
  55                 } else {
  56                         char *path;
  57                         char *p;
  58
  59                         path = env_path;
  60                         /* NOFORK NB: xmalloc inside find_executable(), must have no allocs above! */
  61                         while ((p = find_executable(*argv, &path)) != NULL) {
  62                                 missing = 0;
  63                                 puts(p);
  64                                 free(p);
  65                                 if (!option_mask32) /* -a not set */
  66                                         break;
  67                         }
  68                 }
  69                 status |= missing;
  70         } while (*++argv);
  71
  72         return status;
  73 }