1*4882a593Smuzhiyun /* Copyright (C) 2006 by Paolo Giarrusso - modified from glibc' execvp.c.
2*4882a593Smuzhiyun Original copyright notice follows:
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun Copyright (C) 1991,92,1995-99,2002,2004 Free Software Foundation, Inc.
5*4882a593Smuzhiyun This file is part of the GNU C Library.
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun The GNU C Library is free software; you can redistribute it and/or
8*4882a593Smuzhiyun modify it under the terms of the GNU Lesser General Public
9*4882a593Smuzhiyun License as published by the Free Software Foundation; either
10*4882a593Smuzhiyun version 2.1 of the License, or (at your option) any later version.
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun The GNU C Library is distributed in the hope that it will be useful,
13*4882a593Smuzhiyun but WITHOUT ANY WARRANTY; without even the implied warranty of
14*4882a593Smuzhiyun MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15*4882a593Smuzhiyun Lesser General Public License for more details.
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun You should have received a copy of the GNU Lesser General Public
18*4882a593Smuzhiyun License along with the GNU C Library; if not, write to the Free
19*4882a593Smuzhiyun Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
20*4882a593Smuzhiyun 02111-1307 USA. */
21*4882a593Smuzhiyun #include <unistd.h>
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun #include <stdbool.h>
24*4882a593Smuzhiyun #include <stdlib.h>
25*4882a593Smuzhiyun #include <string.h>
26*4882a593Smuzhiyun #include <errno.h>
27*4882a593Smuzhiyun #include <limits.h>
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun #ifndef TEST
30*4882a593Smuzhiyun #include <um_malloc.h>
31*4882a593Smuzhiyun #else
32*4882a593Smuzhiyun #include <stdio.h>
33*4882a593Smuzhiyun #define um_kmalloc malloc
34*4882a593Smuzhiyun #endif
35*4882a593Smuzhiyun #include <os.h>
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun /* Execute FILE, searching in the `PATH' environment variable if it contains
38*4882a593Smuzhiyun no slashes, with arguments ARGV and environment from `environ'. */
execvp_noalloc(char * buf,const char * file,char * const argv[])39*4882a593Smuzhiyun int execvp_noalloc(char *buf, const char *file, char *const argv[])
40*4882a593Smuzhiyun {
41*4882a593Smuzhiyun if (*file == '\0') {
42*4882a593Smuzhiyun return -ENOENT;
43*4882a593Smuzhiyun }
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun if (strchr (file, '/') != NULL) {
46*4882a593Smuzhiyun /* Don't search when it contains a slash. */
47*4882a593Smuzhiyun execv(file, argv);
48*4882a593Smuzhiyun } else {
49*4882a593Smuzhiyun int got_eacces;
50*4882a593Smuzhiyun size_t len, pathlen;
51*4882a593Smuzhiyun char *name, *p;
52*4882a593Smuzhiyun char *path = getenv("PATH");
53*4882a593Smuzhiyun if (path == NULL)
54*4882a593Smuzhiyun path = ":/bin:/usr/bin";
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun len = strlen(file) + 1;
57*4882a593Smuzhiyun pathlen = strlen(path);
58*4882a593Smuzhiyun /* Copy the file name at the top. */
59*4882a593Smuzhiyun name = memcpy(buf + pathlen + 1, file, len);
60*4882a593Smuzhiyun /* And add the slash. */
61*4882a593Smuzhiyun *--name = '/';
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun got_eacces = 0;
64*4882a593Smuzhiyun p = path;
65*4882a593Smuzhiyun do {
66*4882a593Smuzhiyun char *startp;
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun path = p;
69*4882a593Smuzhiyun //Let's avoid this GNU extension.
70*4882a593Smuzhiyun //p = strchrnul (path, ':');
71*4882a593Smuzhiyun p = strchr(path, ':');
72*4882a593Smuzhiyun if (!p)
73*4882a593Smuzhiyun p = strchr(path, '\0');
74*4882a593Smuzhiyun
75*4882a593Smuzhiyun if (p == path)
76*4882a593Smuzhiyun /* Two adjacent colons, or a colon at the beginning or the end
77*4882a593Smuzhiyun of `PATH' means to search the current directory. */
78*4882a593Smuzhiyun startp = name + 1;
79*4882a593Smuzhiyun else
80*4882a593Smuzhiyun startp = memcpy(name - (p - path), path, p - path);
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun /* Try to execute this name. If it works, execv will not return. */
83*4882a593Smuzhiyun execv(startp, argv);
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun /*
86*4882a593Smuzhiyun if (errno == ENOEXEC) {
87*4882a593Smuzhiyun }
88*4882a593Smuzhiyun */
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun switch (errno) {
91*4882a593Smuzhiyun case EACCES:
92*4882a593Smuzhiyun /* Record the we got a `Permission denied' error. If we end
93*4882a593Smuzhiyun up finding no executable we can use, we want to diagnose
94*4882a593Smuzhiyun that we did find one but were denied access. */
95*4882a593Smuzhiyun got_eacces = 1;
96*4882a593Smuzhiyun case ENOENT:
97*4882a593Smuzhiyun case ESTALE:
98*4882a593Smuzhiyun case ENOTDIR:
99*4882a593Smuzhiyun /* Those errors indicate the file is missing or not executable
100*4882a593Smuzhiyun by us, in which case we want to just try the next path
101*4882a593Smuzhiyun directory. */
102*4882a593Smuzhiyun case ENODEV:
103*4882a593Smuzhiyun case ETIMEDOUT:
104*4882a593Smuzhiyun /* Some strange filesystems like AFS return even
105*4882a593Smuzhiyun stranger error numbers. They cannot reasonably mean
106*4882a593Smuzhiyun anything else so ignore those, too. */
107*4882a593Smuzhiyun case ENOEXEC:
108*4882a593Smuzhiyun /* We won't go searching for the shell
109*4882a593Smuzhiyun * if it is not executable - the Linux
110*4882a593Smuzhiyun * kernel already handles this enough,
111*4882a593Smuzhiyun * for us. */
112*4882a593Smuzhiyun break;
113*4882a593Smuzhiyun
114*4882a593Smuzhiyun default:
115*4882a593Smuzhiyun /* Some other error means we found an executable file, but
116*4882a593Smuzhiyun something went wrong executing it; return the error to our
117*4882a593Smuzhiyun caller. */
118*4882a593Smuzhiyun return -errno;
119*4882a593Smuzhiyun }
120*4882a593Smuzhiyun } while (*p++ != '\0');
121*4882a593Smuzhiyun
122*4882a593Smuzhiyun /* We tried every element and none of them worked. */
123*4882a593Smuzhiyun if (got_eacces)
124*4882a593Smuzhiyun /* At least one failure was due to permissions, so report that
125*4882a593Smuzhiyun error. */
126*4882a593Smuzhiyun return -EACCES;
127*4882a593Smuzhiyun }
128*4882a593Smuzhiyun
129*4882a593Smuzhiyun /* Return the error from the last attempt (probably ENOENT). */
130*4882a593Smuzhiyun return -errno;
131*4882a593Smuzhiyun }
132*4882a593Smuzhiyun #ifdef TEST
main(int argc,char ** argv)133*4882a593Smuzhiyun int main(int argc, char**argv)
134*4882a593Smuzhiyun {
135*4882a593Smuzhiyun char buf[PATH_MAX];
136*4882a593Smuzhiyun int ret;
137*4882a593Smuzhiyun argc--;
138*4882a593Smuzhiyun if (!argc) {
139*4882a593Smuzhiyun os_warn("Not enough arguments\n");
140*4882a593Smuzhiyun return 1;
141*4882a593Smuzhiyun }
142*4882a593Smuzhiyun argv++;
143*4882a593Smuzhiyun if (ret = execvp_noalloc(buf, argv[0], argv)) {
144*4882a593Smuzhiyun errno = -ret;
145*4882a593Smuzhiyun perror("execvp_noalloc");
146*4882a593Smuzhiyun }
147*4882a593Smuzhiyun return 0;
148*4882a593Smuzhiyun }
149*4882a593Smuzhiyun #endif
150