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1 /* Locating a program in PATH. |
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2 Copyright (C) 2001-2003 Free Software Foundation, Inc. |
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3 Written by Bruno Haible <haible@clisp.cons.org>, 2001. |
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4 |
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5 This program is free software; you can redistribute it and/or modify |
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6 it under the terms of the GNU General Public License as published by |
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7 the Free Software Foundation; either version 2, or (at your option) |
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8 any later version. |
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9 |
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10 This program is distributed in the hope that it will be useful, |
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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13 GNU General Public License for more details. |
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14 |
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15 You should have received a copy of the GNU General Public License |
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16 along with this program; if not, write to the Free Software Foundation, |
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17 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
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18 |
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19 |
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20 #ifdef HAVE_CONFIG_H |
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21 # include "config.h" |
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22 #endif |
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23 |
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24 /* Specification. */ |
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25 #include "findprog.h" |
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26 |
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27 #include <stdbool.h> |
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28 #include <stdlib.h> |
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29 #include <string.h> |
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30 |
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31 #ifdef HAVE_UNISTD_H |
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32 # include <unistd.h> |
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33 #endif |
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34 |
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35 #include "xalloc.h" |
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36 #include "pathname.h" |
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37 |
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38 |
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39 const char * |
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40 find_in_path (const char *progname) |
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41 { |
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42 #if defined _WIN32 || defined __WIN32__ || defined __EMX__ || defined __DJGPP__ |
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43 /* Win32, OS/2, DOS */ |
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44 /* The searching rules with .COM, .EXE, .BAT, .CMD etc. suffixes are |
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45 too complicated. Leave it to the OS. */ |
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46 return progname; |
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47 #else |
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48 /* Unix */ |
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49 char *path; |
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50 char *dir; |
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51 char *cp; |
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52 |
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53 if (strchr (progname, '/') != NULL) |
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54 /* If progname contains a slash, it is either absolute or relative to |
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55 the current directory. PATH is not used. */ |
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56 return progname; |
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57 |
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58 path = getenv ("PATH"); |
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59 if (path == NULL || *path == '\0') |
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60 /* If PATH is not set, the default search path is implementation |
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61 dependent. */ |
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62 return progname; |
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63 |
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64 /* Make a copy, to prepare for destructive modifications. */ |
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65 path = xstrdup (path); |
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66 for (dir = path; ; dir = cp + 1) |
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67 { |
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68 bool last; |
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69 char *progpathname; |
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70 |
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71 /* Extract next directory in PATH. */ |
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72 for (cp = dir; *cp != '\0' && *cp != ':'; cp++) |
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73 ; |
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74 last = (*cp == '\0'); |
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75 *cp = '\0'; |
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76 |
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77 /* Empty PATH components designate the current directory. */ |
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78 if (dir == cp) |
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79 dir = "."; |
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80 |
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81 /* Concatenate dir and progname. */ |
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82 progpathname = concatenated_pathname (dir, progname, NULL); |
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83 |
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84 /* On systems which have the eaccess() system call, let's use it. |
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85 On other systems, let's hope that this program is not installed |
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86 setuid or setgid, so that it is ok to call access() despite its |
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87 design flaw. */ |
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88 if (eaccess (progpathname, X_OK) == 0) |
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89 { |
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90 /* Found! */ |
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91 if (strcmp (progpathname, progname) == 0) |
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92 { |
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93 free (progpathname); |
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94 |
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95 /* Add the "./" prefix for real, that concatenated_pathname() |
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96 optimized away. This avoids a second PATH search when the |
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97 caller uses execlp/execvp. */ |
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98 progpathname = xmalloc (2 + strlen (progname) + 1); |
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99 progpathname[0] = '.'; |
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100 progpathname[1] = '/'; |
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101 memcpy (progpathname + 2, progname, strlen (progname) + 1); |
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102 } |
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103 |
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104 free (path); |
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105 return progpathname; |
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106 } |
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107 |
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108 free (progpathname); |
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109 |
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110 if (last) |
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111 break; |
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112 } |
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113 |
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114 /* Not found in PATH. An error will be signalled at the first call. */ |
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115 free (path); |
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116 return progname; |
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117 #endif |
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118 } |
