freebsd-dev/lib/libc/gen/wordexp.c
Pedro F. Giffuni d915a14ef0 libc: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-25 17:12:48 +00:00

413 lines
10 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2002 Tim J. Robbins.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "namespace.h"
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wordexp.h>
#include "un-namespace.h"
#include "libc_private.h"
__FBSDID("$FreeBSD$");
static int we_askshell(const char *, wordexp_t *, int);
static int we_check(const char *);
/*
* wordexp --
* Perform shell word expansion on `words' and place the resulting list
* of words in `we'. See wordexp(3).
*
* Specified by IEEE Std. 1003.1-2001.
*/
int
wordexp(const char * __restrict words, wordexp_t * __restrict we, int flags)
{
int error;
if (flags & WRDE_REUSE)
wordfree(we);
if ((flags & WRDE_APPEND) == 0) {
we->we_wordc = 0;
we->we_wordv = NULL;
we->we_strings = NULL;
we->we_nbytes = 0;
}
if ((error = we_check(words)) != 0) {
wordfree(we);
return (error);
}
if ((error = we_askshell(words, we, flags)) != 0) {
wordfree(we);
return (error);
}
return (0);
}
static size_t
we_read_fully(int fd, char *buffer, size_t len)
{
size_t done;
ssize_t nread;
done = 0;
do {
nread = _read(fd, buffer + done, len - done);
if (nread == -1 && errno == EINTR)
continue;
if (nread <= 0)
break;
done += nread;
} while (done != len);
return done;
}
static bool
we_write_fully(int fd, const char *buffer, size_t len)
{
size_t done;
ssize_t nwritten;
done = 0;
do {
nwritten = _write(fd, buffer + done, len - done);
if (nwritten == -1 && errno == EINTR)
continue;
if (nwritten <= 0)
return (false);
done += nwritten;
} while (done != len);
return (true);
}
/*
* we_askshell --
* Use the `freebsd_wordexp' /bin/sh builtin function to do most of the
* work in expanding the word string. This function is complicated by
* memory management.
*/
static int
we_askshell(const char *words, wordexp_t *we, int flags)
{
int pdesw[2]; /* Pipe for writing words */
int pdes[2]; /* Pipe for reading output */
char wfdstr[sizeof(int) * 3 + 1];
char buf[35]; /* Buffer for byte and word count */
long nwords, nbytes; /* Number of words, bytes from child */
long i; /* Handy integer */
size_t sofs; /* Offset into we->we_strings */
size_t vofs; /* Offset into we->we_wordv */
pid_t pid; /* Process ID of child */
pid_t wpid; /* waitpid return value */
int status; /* Child exit status */
int error; /* Our return value */
int serrno; /* errno to return */
char *np, *p; /* Handy pointers */
char *nstrings; /* Temporary for realloc() */
char **nwv; /* Temporary for realloc() */
sigset_t newsigblock, oldsigblock;
const char *ifs;
serrno = errno;
ifs = getenv("IFS");
if (pipe2(pdesw, O_CLOEXEC) < 0)
return (WRDE_NOSPACE); /* XXX */
snprintf(wfdstr, sizeof(wfdstr), "%d", pdesw[0]);
if (pipe2(pdes, O_CLOEXEC) < 0) {
_close(pdesw[0]);
_close(pdesw[1]);
return (WRDE_NOSPACE); /* XXX */
}
(void)sigemptyset(&newsigblock);
(void)sigaddset(&newsigblock, SIGCHLD);
(void)__libc_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
if ((pid = fork()) < 0) {
serrno = errno;
_close(pdesw[0]);
_close(pdesw[1]);
_close(pdes[0]);
_close(pdes[1]);
(void)__libc_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
errno = serrno;
return (WRDE_NOSPACE); /* XXX */
}
else if (pid == 0) {
/*
* We are the child; make /bin/sh expand `words'.
*/
(void)__libc_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
if ((pdes[1] != STDOUT_FILENO ?
_dup2(pdes[1], STDOUT_FILENO) :
_fcntl(pdes[1], F_SETFD, 0)) < 0)
_exit(1);
if (_fcntl(pdesw[0], F_SETFD, 0) < 0)
_exit(1);
execl(_PATH_BSHELL, "sh", flags & WRDE_UNDEF ? "-u" : "+u",
"-c", "IFS=$1;eval \"$2\";"
"freebsd_wordexp -f \"$3\" ${4:+\"$4\"}",
"",
ifs != NULL ? ifs : " \t\n",
flags & WRDE_SHOWERR ? "" : "exec 2>/dev/null",
wfdstr,
flags & WRDE_NOCMD ? "-p" : "",
(char *)NULL);
_exit(1);
}
/*
* We are the parent; write the words.
*/
_close(pdes[1]);
_close(pdesw[0]);
if (!we_write_fully(pdesw[1], words, strlen(words))) {
_close(pdesw[1]);
error = WRDE_SYNTAX;
goto cleanup;
}
_close(pdesw[1]);
/*
* Read the output of the shell wordexp function,
* which is a byte indicating that the words were parsed successfully,
* a 64-bit hexadecimal word count, a dummy byte, a 64-bit hexadecimal
* byte count (not including terminating null bytes), followed by the
* expanded words separated by nulls.
*/
switch (we_read_fully(pdes[0], buf, 34)) {
case 1:
error = buf[0] == 'C' ? WRDE_CMDSUB : WRDE_BADVAL;
serrno = errno;
goto cleanup;
case 34:
break;
default:
error = WRDE_SYNTAX;
serrno = errno;
goto cleanup;
}
buf[17] = '\0';
nwords = strtol(buf + 1, NULL, 16);
buf[34] = '\0';
nbytes = strtol(buf + 18, NULL, 16) + nwords;
/*
* Allocate or reallocate (when flags & WRDE_APPEND) the word vector
* and string storage buffers for the expanded words we're about to
* read from the child.
*/
sofs = we->we_nbytes;
vofs = we->we_wordc;
if ((flags & (WRDE_DOOFFS|WRDE_APPEND)) == (WRDE_DOOFFS|WRDE_APPEND))
vofs += we->we_offs;
we->we_wordc += nwords;
we->we_nbytes += nbytes;
if ((nwv = reallocarray(we->we_wordv, (we->we_wordc + 1 +
(flags & WRDE_DOOFFS ? we->we_offs : 0)),
sizeof(char *))) == NULL) {
error = WRDE_NOSPACE;
goto cleanup;
}
we->we_wordv = nwv;
if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) {
error = WRDE_NOSPACE;
goto cleanup;
}
for (i = 0; i < vofs; i++)
if (we->we_wordv[i] != NULL)
we->we_wordv[i] += nstrings - we->we_strings;
we->we_strings = nstrings;
if (we_read_fully(pdes[0], we->we_strings + sofs, nbytes) != nbytes) {
error = WRDE_NOSPACE; /* abort for unknown reason */
serrno = errno;
goto cleanup;
}
error = 0;
cleanup:
_close(pdes[0]);
do
wpid = _waitpid(pid, &status, 0);
while (wpid < 0 && errno == EINTR);
(void)__libc_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
if (error != 0) {
errno = serrno;
return (error);
}
if (wpid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0)
return (WRDE_NOSPACE); /* abort for unknown reason */
/*
* Break the null-terminated expanded word strings out into
* the vector.
*/
if (vofs == 0 && flags & WRDE_DOOFFS)
while (vofs < we->we_offs)
we->we_wordv[vofs++] = NULL;
p = we->we_strings + sofs;
while (nwords-- != 0) {
we->we_wordv[vofs++] = p;
if ((np = memchr(p, '\0', nbytes)) == NULL)
return (WRDE_NOSPACE); /* XXX */
nbytes -= np - p + 1;
p = np + 1;
}
we->we_wordv[vofs] = NULL;
return (0);
}
/*
* we_check --
* Check that the string contains none of the following unquoted
* special characters: <newline> |&;<>(){}
* This mainly serves for {} which are normally legal in sh.
* It deliberately does not attempt to model full sh syntax.
*/
static int
we_check(const char *words)
{
char c;
/* Saw \ or $, possibly not special: */
bool quote = false, dollar = false;
/* Saw ', ", ${, ` or $(, possibly not special: */
bool have_sq = false, have_dq = false, have_par_begin = false;
bool have_cmd = false;
/* Definitely saw a ', ", ${, ` or $(, need a closing character: */
bool need_sq = false, need_dq = false, need_par_end = false;
bool need_cmd_old = false, need_cmd_new = false;
while ((c = *words++) != '\0') {
switch (c) {
case '\\':
quote = !quote;
continue;
case '$':
if (quote)
quote = false;
else
dollar = !dollar;
continue;
case '\'':
if (!quote && !have_sq && !have_dq)
need_sq = true;
else
need_sq = false;
have_sq = true;
break;
case '"':
if (!quote && !have_sq && !have_dq)
need_dq = true;
else
need_dq = false;
have_dq = true;
break;
case '`':
if (!quote && !have_sq && !have_cmd)
need_cmd_old = true;
else
need_cmd_old = false;
have_cmd = true;
break;
case '{':
if (!quote && !dollar && !have_sq && !have_dq &&
!have_cmd)
return (WRDE_BADCHAR);
if (dollar) {
if (!quote && !have_sq)
need_par_end = true;
have_par_begin = true;
}
break;
case '}':
if (!quote && !have_sq && !have_dq && !have_par_begin &&
!have_cmd)
return (WRDE_BADCHAR);
need_par_end = false;
break;
case '(':
if (!quote && !dollar && !have_sq && !have_dq &&
!have_cmd)
return (WRDE_BADCHAR);
if (dollar) {
if (!quote && !have_sq)
need_cmd_new = true;
have_cmd = true;
}
break;
case ')':
if (!quote && !have_sq && !have_dq && !have_cmd)
return (WRDE_BADCHAR);
need_cmd_new = false;
break;
case '|': case '&': case ';': case '<': case '>': case '\n':
if (!quote && !have_sq && !have_dq && !have_cmd)
return (WRDE_BADCHAR);
break;
default:
break;
}
quote = dollar = false;
}
if (quote || dollar || need_sq || need_dq || need_par_end ||
need_cmd_old || need_cmd_new)
return (WRDE_SYNTAX);
return (0);
}
/*
* wordfree --
* Free the result of wordexp(). See wordexp(3).
*
* Specified by IEEE Std. 1003.1-2001.
*/
void
wordfree(wordexp_t *we)
{
if (we == NULL)
return;
free(we->we_wordv);
free(we->we_strings);
we->we_wordv = NULL;
we->we_strings = NULL;
we->we_nbytes = 0;
we->we_wordc = 0;
}