glibc/posix/execvp.c

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1995-02-18 02:27:10 +01:00
/* Copyright (C) 1991, 1992 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <unistd.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <limits.h>
#include <sys/types.h>
#ifndef HAVE_GNU_LD
#define __environ environ
#endif
/* Execute FILE, searching in the `PATH' environment variable if it contains
no slashes, with arguments ARGV and environment from `environ'. */
int
DEFUN(execvp, (file, argv), CONST char *file AND char *CONST argv[])
{
if (strchr (file, '/') == NULL)
{
char *path, *p;
struct stat st;
size_t len;
uid_t uid;
gid_t gid;
int ngroups;
gid_t groups[NGROUPS_MAX];
char *name;
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;
name = __alloca (strlen (path) + len);
uid = geteuid ();
gid = getegid ();
ngroups = getgroups (sizeof (groups) / sizeof (groups[0]), groups);
p = path;
do
{
path = p;
p = strchr (path, ':');
if (p == NULL)
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. */
(void) memcpy (name, file, len);
else
{
/* Construct the pathname to try. */
(void) memcpy (name, path, p - path);
name[p - path] = '/';
(void) memcpy (&name[(p - path) + 1], file, len);
}
if (stat (name, &st) == 0 && S_ISREG (st.st_mode))
{
int bit = S_IXOTH;
if (st.st_uid == uid)
bit = S_IXUSR;
else if (st.st_gid == gid)
bit = S_IXGRP;
else
{
register int i;
for (i = 0; i < ngroups; ++i)
if (st.st_gid == groups[i])
{
bit = S_IXGRP;
break;
}
}
if (st.st_mode & bit)
{
file = name;
break;
}
}
}
while (*p++ != '\0');
}
return __execve (file, argv, __environ);
}