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
|
/* Copyright (C) 1991, 92, 95, 96, 97, 98, 99 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <unistd.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <paths.h>
/* The file is accessible but it is not an executable file. Invoke
the shell to interpret it as a script. */
static void
internal_function
script_execute (const char *file, char *const argv[])
{
/* Count the arguments. */
int argc = 0;
while (argv[argc++])
;
/* Construct an argument list for the shell. */
{
char *new_argv[argc + 1];
new_argv[0] = (char *) _PATH_BSHELL;
new_argv[1] = (char *) file;
while (argc > 1)
{
new_argv[argc] = argv[argc - 1];
--argc;
}
/* Execute the shell. */
__execve (new_argv[0], new_argv, __environ);
}
}
/* Execute FILE, searching in the `PATH' environment variable if it contains
no slashes, with arguments ARGV and environment from `environ'. */
int
execvp (file, argv)
const char *file;
char *const argv[];
{
if (*file == '\0')
{
/* We check the simple case first. */
__set_errno (ENOENT);
return -1;
}
if (strchr (file, '/') != NULL)
{
/* Don't search when it contains a slash. */
__execve (file, argv, __environ);
if (errno == ENOEXEC)
script_execute (file, argv);
}
else
{
int got_eacces = 0;
char *path, *p, *name;
size_t len;
size_t pathlen;
path = getenv ("PATH");
if (path == NULL)
{
/* There is no `PATH' in the environment.
The default search path is the current directory
followed by the path `confstr' returns for `_CS_PATH'. */
len = confstr (_CS_PATH, (char *) NULL, 0);
path = (char *) __alloca (1 + len);
path[0] = ':';
(void) confstr (_CS_PATH, path + 1, len);
}
len = strlen (file) + 1;
pathlen = strlen (path);
name = __alloca (pathlen + len + 1);
/* Copy the file name at the top. */
name = (char *) memcpy (name + pathlen + 1, file, len);
/* And add the slash. */
*--name = '/';
p = path;
do
{
char *startp;
path = p;
p = __strchrnul (path, ':');
if (p == path)
/* Two adjacent colons, or a colon at the beginning or the end
of `PATH' means to search the current directory. */
startp = name + 1;
else
startp = (char *) memcpy (name - (p - path), path, p - path);
/* Try to execute this name. If it works, execv will not return. */
__execve (startp, argv, __environ);
if (errno == ENOEXEC)
script_execute (startp, argv);
switch (errno)
{
case EACCES:
/* Record the we got a `Permission denied' error. If we end
up finding no executable we can use, we want to diagnose
that we did find one but were denied access. */
got_eacces = 1;
case ENOENT:
case ESTALE:
case ENOTDIR:
/* Those errors indicate the file is missing or not executable
by us, in which case we want to just try the next path
directory. */
break;
default:
/* Some other error means we found an executable file, but
something went wrong executing it; return the error to our
caller. */
return -1;
}
}
while (*p++ != '\0');
/* We tried every element and none of them worked. */
if (got_eacces)
/* At least one failure was due to permissions, so report that
error. */
__set_errno (EACCES);
}
/* Return the error from the last attempt (probably ENOENT). */
return -1;
}
|
