1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
|
/* Locating a program in a given path.
Copyright (C) 2001-2004, 2006-2020 Free Software Foundation, Inc.
Written by Bruno Haible <haible@clisp.cons.org>, 2001, 2019.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "findprog.h"
#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "filename.h"
#include "concat-filename.h"
#include "xalloc.h"
#if (defined _WIN32 && !defined __CYGWIN__) || defined __EMX__ || defined __DJGPP__
/* Native Windows, OS/2, DOS */
# define NATIVE_SLASH '\\'
#else
/* Unix */
# define NATIVE_SLASH '/'
#endif
/* Separator in PATH like lists of pathnames. */
#if (defined _WIN32 && !defined __CYGWIN__) || defined __EMX__ || defined __DJGPP__
/* Native Windows, OS/2, DOS */
# define PATH_SEPARATOR ';'
#else
/* Unix */
# define PATH_SEPARATOR ':'
#endif
/* The list of suffixes that the execlp/execvp function tries when searching
for the program. */
static const char * const suffixes[] =
{
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
"", ".com", ".exe", ".bat", ".cmd"
/* Note: Files without any suffix are not considered executable. */
/* Note: The cmd.exe program does a different lookup: It searches according
to the PATHEXT environment variable.
See <https://stackoverflow.com/questions/7839150/>.
Also, it executes files ending .bat and .cmd directly without letting the
kernel interpret the program file. */
#elif defined __CYGWIN__
"", ".exe", ".com"
#elif defined __EMX__
"", ".exe"
#elif defined __DJGPP__
"", ".com", ".exe", ".bat"
#else /* Unix */
""
#endif
};
const char *
find_in_given_path (const char *progname, const char *path,
bool optimize_for_exec)
{
{
bool has_slash = false;
{
const char *p;
for (p = progname; *p != '\0'; p++)
if (ISSLASH (*p))
{
has_slash = true;
break;
}
}
if (has_slash)
{
/* If progname contains a slash, it is either absolute or relative to
the current directory. PATH is not used. */
if (optimize_for_exec)
/* The execl/execv/execlp/execvp functions will try the various
suffixes anyway and fail if no executable is found. */
return progname;
else
{
/* Try the various suffixes and see whether one of the files
with such a suffix is actually executable. */
int failure_errno;
size_t i;
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
const char *progbasename;
{
const char *p;
progbasename = progname;
for (p = progname; *p != '\0'; p++)
if (ISSLASH (*p))
progbasename = p + 1;
}
#endif
/* Try all platform-dependent suffixes. */
failure_errno = ENOENT;
for (i = 0; i < sizeof (suffixes) / sizeof (suffixes[0]); i++)
{
const char *suffix = suffixes[i];
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
/* File names without a '.' are not considered executable, and
for file names with a '.' no additional suffix is tried. */
if ((*suffix != '\0') != (strchr (progbasename, '.') != NULL))
#endif
{
/* Concatenate progname and suffix. */
char *progpathname =
xconcatenated_filename ("", progname, suffix);
/* On systems which have the eaccess() system call, let's
use it. On other systems, let's hope that this program
is not installed setuid or setgid, so that it is ok to
call access() despite its design flaw. */
if (eaccess (progpathname, X_OK) == 0)
{
/* Found! */
if (strcmp (progpathname, progname) == 0)
{
free (progpathname);
return progname;
}
else
return progpathname;
}
if (errno != ENOENT)
failure_errno = errno;
free (progpathname);
}
}
errno = failure_errno;
return NULL;
}
}
}
if (path == NULL)
/* If PATH is not set, the default search path is implementation dependent.
In practice, it is treated like an empty PATH. */
path = "";
{
int failure_errno;
/* Make a copy, to prepare for destructive modifications. */
char *path_copy = xstrdup (path);
char *path_rest;
char *cp;
failure_errno = ENOENT;
for (path_rest = path_copy; ; path_rest = cp + 1)
{
const char *dir;
bool last;
size_t i;
/* Extract next directory in PATH. */
dir = path_rest;
for (cp = path_rest; *cp != '\0' && *cp != PATH_SEPARATOR; cp++)
;
last = (*cp == '\0');
*cp = '\0';
/* Empty PATH components designate the current directory. */
if (dir == cp)
dir = ".";
/* Try all platform-dependent suffixes. */
for (i = 0; i < sizeof (suffixes) / sizeof (suffixes[0]); i++)
{
const char *suffix = suffixes[i];
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
/* File names without a '.' are not considered executable, and
for file names with a '.' no additional suffix is tried. */
if ((*suffix != '\0') != (strchr (progname, '.') != NULL))
#endif
{
/* Concatenate dir, progname, and suffix. */
char *progpathname =
xconcatenated_filename (dir, progname, suffix);
/* On systems which have the eaccess() system call, let's
use it. On other systems, let's hope that this program
is not installed setuid or setgid, so that it is ok to
call access() despite its design flaw. */
if (eaccess (progpathname, X_OK) == 0)
{
/* Found! */
if (strcmp (progpathname, progname) == 0)
{
free (progpathname);
/* Add the "./" prefix for real, that
xconcatenated_filename() optimized away. This
avoids a second PATH search when the caller uses
execl/execv/execlp/execvp. */
progpathname =
XNMALLOC (2 + strlen (progname) + 1, char);
progpathname[0] = '.';
progpathname[1] = NATIVE_SLASH;
memcpy (progpathname + 2, progname,
strlen (progname) + 1);
}
free (path_copy);
return progpathname;
}
if (errno != ENOENT)
failure_errno = errno;
free (progpathname);
}
}
if (last)
break;
}
/* Not found in PATH. */
free (path_copy);
errno = failure_errno;
return NULL;
}
}
|
