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[glibc.git] / posix / execvp.c
blob963b769fca1871d5cce369605ab54ec83d68e79c
1 /* Copyright (C) 1991, 92, 95, 96, 97, 98, 99 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
19 #include <unistd.h>
20 #include <stdarg.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <errno.h>
24 #include <paths.h>
27 /* The file is accessible but it is not an executable file. Invoke
28 the shell to interpret it as a script. */
29 static void
30 internal_function
31 script_execute (const char *file, char *const argv[])
33 /* Count the arguments. */
34 int argc = 0;
35 while (argv[argc++])
38 /* Construct an argument list for the shell. */
40 char *new_argv[argc + 1];
41 new_argv[0] = (char *) _PATH_BSHELL;
42 new_argv[1] = (char *) file;
43 while (argc > 1)
45 new_argv[argc] = argv[argc - 1];
46 --argc;
49 /* Execute the shell. */
50 __execve (new_argv[0], new_argv, __environ);
55 /* Execute FILE, searching in the `PATH' environment variable if it contains
56 no slashes, with arguments ARGV and environment from `environ'. */
57 int
58 execvp (file, argv)
59 const char *file;
60 char *const argv[];
62 if (*file == '\0')
64 /* We check the simple case first. */
65 __set_errno (ENOENT);
66 return -1;
69 if (strchr (file, '/') != NULL)
71 /* Don't search when it contains a slash. */
72 __execve (file, argv, __environ);
74 if (errno == ENOEXEC)
75 script_execute (file, argv);
77 else
79 int got_eacces = 0;
80 char *path, *p, *name;
81 size_t len;
82 size_t pathlen;
84 path = getenv ("PATH");
85 if (path == NULL)
87 /* There is no `PATH' in the environment.
88 The default search path is the current directory
89 followed by the path `confstr' returns for `_CS_PATH'. */
90 len = confstr (_CS_PATH, (char *) NULL, 0);
91 path = (char *) __alloca (1 + len);
92 path[0] = ':';
93 (void) confstr (_CS_PATH, path + 1, len);
96 len = strlen (file) + 1;
97 pathlen = strlen (path);
98 name = __alloca (pathlen + len + 1);
99 /* Copy the file name at the top. */
100 name = (char *) memcpy (name + pathlen + 1, file, len);
101 /* And add the slash. */
102 *--name = '/';
104 p = path;
107 char *startp;
109 path = p;
110 p = __strchrnul (path, ':');
112 if (p == path)
113 /* Two adjacent colons, or a colon at the beginning or the end
114 of `PATH' means to search the current directory. */
115 startp = name + 1;
116 else
117 startp = (char *) memcpy (name - (p - path), path, p - path);
119 /* Try to execute this name. If it works, execv will not return. */
120 __execve (startp, argv, __environ);
122 if (errno == ENOEXEC)
123 script_execute (startp, argv);
125 switch (errno)
127 case EACCES:
128 /* Record the we got a `Permission denied' error. If we end
129 up finding no executable we can use, we want to diagnose
130 that we did find one but were denied access. */
131 got_eacces = 1;
132 case ENOENT:
133 case ESTALE:
134 case ENOTDIR:
135 /* Those errors indicate the file is missing or not executable
136 by us, in which case we want to just try the next path
137 directory. */
138 break;
140 default:
141 /* Some other error means we found an executable file, but
142 something went wrong executing it; return the error to our
143 caller. */
144 return -1;
147 while (*p++ != '\0');
149 /* We tried every element and none of them worked. */
150 if (got_eacces)
151 /* At least one failure was due to permissions, so report that
152 error. */
153 __set_errno (EACCES);
156 /* Return the error from the last attempt (probably ENOENT). */
157 return -1;