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freebsd-dev/lib/libc/gen/wordexp.c

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/*-
* 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 <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wordexp.h>
#include "un-namespace.h"
__FBSDID("$FreeBSD$");
static int we_askshell(const char *, wordexp_t *, int);
static int we_check(const char *, int);
/*
* 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, flags)) != 0) {
wordfree(we);
return (error);
}
if ((error = we_askshell(words, we, flags)) != 0) {
wordfree(we);
return (error);
}
return (0);
}
/*
* we_askshell --
* Use the `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 pdes[2]; /* Pipe to child */
char bbuf[9]; /* Buffer for byte count */
char wbuf[9]; /* Buffer for 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 */
int status; /* Child exit status */
char *ifs; /* IFS env. var. */
char *np, *p; /* Handy pointers */
char *nstrings; /* Temporary for realloc() */
char **nwv; /* Temporary for realloc() */
if ((ifs = getenv("IFS")) == NULL)
ifs = " \t\n";
if (pipe(pdes) < 0)
return (WRDE_NOSPACE); /* XXX */
if ((pid = fork()) < 0) {
_close(pdes[0]);
_close(pdes[1]);
return (WRDE_NOSPACE); /* XXX */
}
else if (pid == 0) {
/*
* We are the child; just get /bin/sh to run the wordexp
* builtin on `words'.
*/
int devnull;
char *cmd;
_close(pdes[0]);
if (_dup2(pdes[1], STDOUT_FILENO) < 0)
_exit(1);
_close(pdes[1]);
if (asprintf(&cmd, "wordexp%c%s\n", *ifs, words) < 0)
_exit(1);
if ((flags & WRDE_SHOWERR) == 0) {
if ((devnull = _open(_PATH_DEVNULL, O_RDWR, 0666)) < 0)
_exit(1);
if (_dup2(devnull, STDERR_FILENO) < 0)
_exit(1);
_close(devnull);
}
execl(_PATH_BSHELL, "sh", flags & WRDE_UNDEF ? "-u" : "+u",
"-c", cmd, NULL);
_exit(1);
}
/*
* We are the parent; read the output of the shell wordexp function,
* which is a 32-bit hexadecimal word count, a 32-bit hexadecimal
* byte count (not including terminating null bytes), followed by
* the expanded words separated by nulls.
*/
_close(pdes[1]);
if (_read(pdes[0], wbuf, 8) != 8 || _read(pdes[0], bbuf, 8) != 8) {
_close(pdes[0]);
_waitpid(pid, &status, 0);
return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
}
wbuf[8] = bbuf[8] = '\0';
nwords = strtol(wbuf, NULL, 16);
nbytes = strtol(bbuf, 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_DOOFS|WRDE_APPEND)) == (WRDE_DOOFS|WRDE_APPEND))
vofs += we->we_offs;
we->we_wordc += nwords;
we->we_nbytes += nbytes;
if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 +
(flags & WRDE_DOOFS ? we->we_offs : 0)) *
sizeof(char *))) == NULL) {
_close(pdes[0]);
_waitpid(pid, &status, 0);
return (WRDE_NOSPACE);
}
we->we_wordv = nwv;
if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) {
_close(pdes[0]);
_waitpid(pid, &status, 0);
return (WRDE_NOSPACE);
}
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 (_read(pdes[0], we->we_strings + sofs, nbytes) != nbytes) {
_close(pdes[0]);
_waitpid(pid, &status, 0);
return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
}
if (_waitpid(pid, &status, 0) < 0 || !WIFEXITED(status) ||
WEXITSTATUS(status) != 0) {
_close(pdes[0]);
return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
}
_close(pdes[0]);
/*
* Break the null-terminated expanded word strings out into
* the vector.
*/
if (vofs == 0 && flags & WRDE_DOOFS)
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> |&;<>(){}
* or command substitutions when WRDE_NOCMD is set in flags.
*/
static int
we_check(const char *words, int flags)
{
char c;
int dquote, level, quote, squote;
quote = squote = dquote = 0;
while ((c = *words++) != '\0') {
switch (c) {
case '\\':
quote ^= 1;
continue;
case '\'':
if (quote + dquote == 0)
squote ^= 1;
break;
case '"':
if (quote + squote == 0)
dquote ^= 1;
break;
case '`':
if (quote + squote == 0 && flags & WRDE_NOCMD)
return (WRDE_CMDSUB);
while ((c = *words++) != '\0' && c != '`')
if (c == '\\' && (c = *words++) == '\0')
break;
if (c == '\0')
return (WRDE_SYNTAX);
break;
case '|': case '&': case ';': case '<': case '>':
case '{': case '}': case '(': case ')': case '\n':
if (quote + squote + dquote == 0)
return (WRDE_BADCHAR);
break;
case '$':
if ((c = *words++) == '\0')
break;
else if (quote + squote == 0 && c == '(') {
if (flags & WRDE_NOCMD && *words != '(')
return (WRDE_CMDSUB);
level = 1;
while ((c = *words++) != '\0') {
if (c == '\\') {
if ((c = *words++) == '\0')
break;
} else if (c == '(')
level++;
else if (c == ')' && --level == 0)
break;
}
if (c == '\0' || level != 0)
return (WRDE_SYNTAX);
} else if (quote + squote == 0 && c == '{') {
level = 1;
while ((c = *words++) != '\0') {
if (c == '\\') {
if ((c = *words++) == '\0')
break;
} else if (c == '{')
level++;
else if (c == '}' && --level == 0)
break;
}
if (c == '\0' || level != 0)
return (WRDE_SYNTAX);
} else
c = *--words;
break;
default:
break;
}
quote = 0;
}
if (quote + squote + dquote != 0)
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;
}
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