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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 | /* Copyright (C) 2006 by Paolo Giarrusso - modified from glibc' execvp.c.
Original copyright notice follows:
Copyright (C) 1991,92,1995-99,2002,2004 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 <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#ifndef TEST
#include <um_malloc.h>
#else
#include <stdio.h>
#define um_kmalloc malloc
#endif
#include <os.h>
/* Execute FILE, searching in the `PATH' environment variable if it contains
no slashes, with arguments ARGV and environment from `environ'. */
int execvp_noalloc(char *buf, const char *file, char *const argv[])
{
if (*file == '\0') {
return -ENOENT;
}
if (strchr (file, '/') != NULL) {
/* Don't search when it contains a slash. */
execv(file, argv);
} else {
int got_eacces;
size_t len, pathlen;
char *name, *p;
char *path = getenv("PATH");
if (path == NULL)
path = ":/bin:/usr/bin";
len = strlen(file) + 1;
pathlen = strlen(path);
/* Copy the file name at the top. */
name = memcpy(buf + pathlen + 1, file, len);
/* And add the slash. */
*--name = '/';
got_eacces = 0;
p = path;
do {
char *startp;
path = p;
//Let's avoid this GNU extension.
//p = strchrnul (path, ':');
p = strchr(path, ':');
if (!p)
p = strchr(path, '\0');
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 = memcpy(name - (p - path), path, p - path);
/* Try to execute this name. If it works, execv will not return. */
execv(startp, argv);
/*
if (errno == ENOEXEC) {
}
*/
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. */
case ENODEV:
case ETIMEDOUT:
/* Some strange filesystems like AFS return even
stranger error numbers. They cannot reasonably mean
anything else so ignore those, too. */
case ENOEXEC:
/* We won't go searching for the shell
* if it is not executable - the Linux
* kernel already handles this enough,
* for us. */
break;
default:
/* Some other error means we found an executable file, but
something went wrong executing it; return the error to our
caller. */
return -errno;
}
} 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. */
return -EACCES;
}
/* Return the error from the last attempt (probably ENOENT). */
return -errno;
}
#ifdef TEST
int main(int argc, char**argv)
{
char buf[PATH_MAX];
int ret;
argc--;
if (!argc) {
fprintf(stderr, "Not enough arguments\n");
return 1;
}
argv++;
if (ret = execvp_noalloc(buf, argv[0], argv)) {
errno = -ret;
perror("execvp_noalloc");
}
return 0;
}
#endif
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