145 lines
4.3 KiB
C
145 lines
4.3 KiB
C
/* $NetBSD: posix_spawnp.c,v 1.4 2020/05/11 14:54:34 kre Exp $ */
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/*-
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* Copyright (c) 2011 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Martin Husemann <martin@NetBSD.org>.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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__RCSID("$NetBSD: posix_spawnp.c,v 1.4 2020/05/11 14:54:34 kre Exp $");
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#endif /* LIBC_SCCS and not lint */
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#include "namespace.h"
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#include <assert.h>
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#include <errno.h>
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#include <paths.h>
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#include <spawn.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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int posix_spawnp(pid_t * __restrict pid, const char * __restrict file,
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const posix_spawn_file_actions_t *fa,
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const posix_spawnattr_t * __restrict sa,
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char * const *__restrict cav, char * const *__restrict env)
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{
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char fpath[FILENAME_MAX];
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const char *path, *p;
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size_t lp, ln;
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int err;
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_DIAGASSERT(file != NULL);
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/*
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* If there is a / in the name, fall straight through to posix_spawn().
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*/
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if (strchr(file, '/') != NULL)
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return posix_spawn(pid, file, fa, sa, cav, env);
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/* Get the path we're searching. */
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if ((path = getenv("PATH")) == NULL)
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path = _PATH_DEFPATH;
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/*
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* Find an executable image with the given name in the PATH
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*/
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ln = strlen(file);
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err = 0;
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do {
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/* Find the end of this path element. */
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for (p = path; *path != 0 && *path != ':'; path++)
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continue;
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/*
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* It's a SHELL path -- double, leading and trailing colons
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* mean the current directory.
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*/
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if (p == path) {
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p = ".";
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lp = 1;
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} else
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lp = (size_t)(path - p);
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/*
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* Once we gain chdir/fchdir file actions, this will need
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* serious work, as we must treat "." relative to the
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* target of the (final) chdir performed.
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*
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* Fortunately, that day is yet to come.
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*/
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/*
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* If the path is too long complain. This is a possible
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* security issue; given a way to make the path too long
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* the user may execute the wrong program.
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*/
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if (lp + ln + 2 > sizeof(fpath)) {
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(void)write(STDERR_FILENO, "posix_spawnp: ", 14);
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(void)write(STDERR_FILENO, p, lp);
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(void)write(STDERR_FILENO, ": path too long\n", 16);
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continue;
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}
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memcpy(fpath, p, lp);
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fpath[lp] = '/';
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memcpy(fpath + lp + 1, file, ln);
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fpath[lp + ln + 1] = '\0';
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/*
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* It would be nice (much better) to try posix_spawn()
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* here, using the current fpath as the filename, but
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* there's no guarantee that it is safe to execute it
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* twice (the file actions may screw us) so that we
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* cannot do. This test is weak, barely even adequate.
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* but unless we are forced into making posix_spawmp()
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* become a system call (with PATH as an arg, or an array
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* of possible paths to try, based upon PATH and file)
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* we really have no better method.
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*/
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if (access(fpath, X_OK) == 0)
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break;
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if (err == 0)
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err = errno;
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fpath[0] = '\0';
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} while (*path++ == ':'); /* Otherwise, *path was NUL */
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if (fpath[0] == '\0')
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return err;
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/*
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* Use posix_spawn() with the found binary
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*/
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return posix_spawn(pid, fpath, fa, sa, cav, env);
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}
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