1/*- 2 * Copyright (c) 2002 Tim J. Robbins. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include "namespace.h" 28#include <sys/cdefs.h> 29#include <sys/types.h> 30#include <sys/wait.h> 31#include <errno.h> 32#include <fcntl.h> 33#include <paths.h> 34#include <signal.h> 35#include <stdio.h> 36#include <stdlib.h> 37#include <string.h> 38#include <unistd.h> 39#include <wordexp.h> 40#include "un-namespace.h" 41 42__FBSDID("$FreeBSD$"); 43 44static int we_askshell(const char *, wordexp_t *, int); 45static int we_check(const char *, int); 46 47/* 48 * wordexp -- 49 * Perform shell word expansion on `words' and place the resulting list 50 * of words in `we'. See wordexp(3). 51 * 52 * Specified by IEEE Std. 1003.1-2001. 53 */ 54int 55wordexp(const char * __restrict words, wordexp_t * __restrict we, int flags) 56{ 57 int error; 58 59 if (flags & WRDE_REUSE) 60 wordfree(we); 61 if ((flags & WRDE_APPEND) == 0) { 62 we->we_wordc = 0; 63 we->we_wordv = NULL; 64 we->we_strings = NULL; 65 we->we_nbytes = 0; 66 } 67 if ((error = we_check(words, flags)) != 0) { 68 wordfree(we); 69 return (error); 70 } 71 if ((error = we_askshell(words, we, flags)) != 0) { 72 wordfree(we); 73 return (error); 74 } 75 return (0); 76} 77 78static size_t 79we_read_fully(int fd, char *buffer, size_t len) 80{ 81 size_t done; 82 ssize_t nread; 83 84 done = 0; 85 do { 86 nread = _read(fd, buffer + done, len - done); 87 if (nread == -1 && errno == EINTR) 88 continue; 89 if (nread <= 0) 90 break; 91 done += nread; 92 } while (done != len); 93 return done; 94} 95 96/* 97 * we_askshell -- 98 * Use the `wordexp' /bin/sh builtin function to do most of the work 99 * in expanding the word string. This function is complicated by 100 * memory management. 101 */ 102static int 103we_askshell(const char *words, wordexp_t *we, int flags) 104{ 105 int pdes[2]; /* Pipe to child */ 106 char bbuf[9]; /* Buffer for byte count */ 107 char wbuf[9]; /* Buffer for word count */ 108 long nwords, nbytes; /* Number of words, bytes from child */ 109 long i; /* Handy integer */ 110 size_t sofs; /* Offset into we->we_strings */ 111 size_t vofs; /* Offset into we->we_wordv */ 112 pid_t pid; /* Process ID of child */ 113 pid_t wpid; /* waitpid return value */ 114 int status; /* Child exit status */ 115 int error; /* Our return value */ 116 int serrno; /* errno to return */ 117 char *np, *p; /* Handy pointers */ 118 char *nstrings; /* Temporary for realloc() */ 119 char **nwv; /* Temporary for realloc() */ 120 sigset_t newsigblock, oldsigblock; 121 122 serrno = errno; 123 124 if (pipe2(pdes, O_CLOEXEC) < 0) 125 return (WRDE_NOSPACE); /* XXX */ 126 (void)sigemptyset(&newsigblock); 127 (void)sigaddset(&newsigblock, SIGCHLD); 128 (void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock); 129 if ((pid = fork()) < 0) { 130 serrno = errno; 131 _close(pdes[0]); 132 _close(pdes[1]); 133 (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL); 134 errno = serrno; 135 return (WRDE_NOSPACE); /* XXX */ 136 } 137 else if (pid == 0) { 138 /* 139 * We are the child; just get /bin/sh to run the wordexp 140 * builtin on `words'. 141 */ 142 (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL); 143 if ((pdes[1] != STDOUT_FILENO ? 144 _dup2(pdes[1], STDOUT_FILENO) : 145 _fcntl(pdes[1], F_SETFD, 0)) < 0) 146 _exit(1); 147 execl(_PATH_BSHELL, "sh", flags & WRDE_UNDEF ? "-u" : "+u", 148 "-c", "eval \"$1\";eval \"wordexp $2\"", "", 149 flags & WRDE_SHOWERR ? "" : "exec 2>/dev/null", words, 150 (char *)NULL); 151 _exit(1); 152 } 153 154 /* 155 * We are the parent; read the output of the shell wordexp function, 156 * which is a 32-bit hexadecimal word count, a 32-bit hexadecimal 157 * byte count (not including terminating null bytes), followed by 158 * the expanded words separated by nulls. 159 */ 160 _close(pdes[1]); 161 if (we_read_fully(pdes[0], wbuf, 8) != 8 || 162 we_read_fully(pdes[0], bbuf, 8) != 8) { 163 error = flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX; 164 serrno = errno; 165 goto cleanup; 166 } 167 wbuf[8] = bbuf[8] = '\0'; 168 nwords = strtol(wbuf, NULL, 16); 169 nbytes = strtol(bbuf, NULL, 16) + nwords; 170 171 /* 172 * Allocate or reallocate (when flags & WRDE_APPEND) the word vector 173 * and string storage buffers for the expanded words we're about to 174 * read from the child. 175 */ 176 sofs = we->we_nbytes; 177 vofs = we->we_wordc; 178 if ((flags & (WRDE_DOOFFS|WRDE_APPEND)) == (WRDE_DOOFFS|WRDE_APPEND)) 179 vofs += we->we_offs; 180 we->we_wordc += nwords; 181 we->we_nbytes += nbytes; 182 if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 + 183 (flags & WRDE_DOOFFS ? we->we_offs : 0)) * 184 sizeof(char *))) == NULL) { 185 error = WRDE_NOSPACE; 186 goto cleanup; 187 } 188 we->we_wordv = nwv; 189 if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) { 190 error = WRDE_NOSPACE; 191 goto cleanup; 192 } 193 for (i = 0; i < vofs; i++) 194 if (we->we_wordv[i] != NULL) 195 we->we_wordv[i] += nstrings - we->we_strings; 196 we->we_strings = nstrings; 197 198 if (we_read_fully(pdes[0], we->we_strings + sofs, nbytes) != nbytes) { 199 error = flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX; 200 serrno = errno; 201 goto cleanup; 202 } 203 204 error = 0; 205cleanup: 206 _close(pdes[0]); 207 do 208 wpid = _waitpid(pid, &status, 0); 209 while (wpid < 0 && errno == EINTR); 210 (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL); 211 if (error != 0) { 212 errno = serrno; 213 return (error); 214 } 215 if (wpid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) 216 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 217 218 /* 219 * Break the null-terminated expanded word strings out into 220 * the vector. 221 */ 222 if (vofs == 0 && flags & WRDE_DOOFFS) 223 while (vofs < we->we_offs) 224 we->we_wordv[vofs++] = NULL; 225 p = we->we_strings + sofs; 226 while (nwords-- != 0) { 227 we->we_wordv[vofs++] = p; 228 if ((np = memchr(p, '\0', nbytes)) == NULL) 229 return (WRDE_NOSPACE); /* XXX */ 230 nbytes -= np - p + 1; 231 p = np + 1; 232 } 233 we->we_wordv[vofs] = NULL; 234 235 return (0); 236} 237 238/* 239 * we_check -- 240 * Check that the string contains none of the following unquoted 241 * special characters: <newline> |&;<>(){} 242 * or command substitutions when WRDE_NOCMD is set in flags. 243 */ 244static int 245we_check(const char *words, int flags) 246{ 247 char c; 248 int dquote, level, quote, squote; 249 250 quote = squote = dquote = 0; 251 while ((c = *words++) != '\0') { 252 switch (c) { 253 case '\\': 254 if (squote == 0) 255 quote ^= 1; 256 continue; 257 case '\'': 258 if (quote + dquote == 0) 259 squote ^= 1; 260 break; 261 case '"': 262 if (quote + squote == 0) 263 dquote ^= 1; 264 break; 265 case '`': 266 if (quote + squote == 0 && flags & WRDE_NOCMD) 267 return (WRDE_CMDSUB); 268 while ((c = *words++) != '\0' && c != '`') 269 if (c == '\\' && (c = *words++) == '\0') 270 break; 271 if (c == '\0') 272 return (WRDE_SYNTAX); 273 break; 274 case '|': case '&': case ';': case '<': case '>': 275 case '{': case '}': case '(': case ')': case '\n': 276 if (quote + squote + dquote == 0) 277 return (WRDE_BADCHAR); 278 break; 279 case '$': 280 if ((c = *words++) == '\0') 281 break; 282 else if (quote + squote == 0 && c == '(') { 283 if (flags & WRDE_NOCMD && *words != '(') 284 return (WRDE_CMDSUB); 285 level = 1; 286 while ((c = *words++) != '\0') { 287 if (c == '\\') { 288 if ((c = *words++) == '\0') 289 break; 290 } else if (c == '(') 291 level++; 292 else if (c == ')' && --level == 0) 293 break; 294 } 295 if (c == '\0' || level != 0) 296 return (WRDE_SYNTAX); 297 } else if (quote + squote == 0 && c == '{') { 298 level = 1; 299 while ((c = *words++) != '\0') { 300 if (c == '\\') { 301 if ((c = *words++) == '\0') 302 break; 303 } else if (c == '{') 304 level++; 305 else if (c == '}' && --level == 0) 306 break; 307 } 308 if (c == '\0' || level != 0) 309 return (WRDE_SYNTAX); 310 } else 311 --words; 312 break; 313 default: 314 break; 315 } 316 quote = 0; 317 } 318 if (quote + squote + dquote != 0) 319 return (WRDE_SYNTAX); 320 321 return (0); 322} 323 324/* 325 * wordfree -- 326 * Free the result of wordexp(). See wordexp(3). 327 * 328 * Specified by IEEE Std. 1003.1-2001. 329 */ 330void 331wordfree(wordexp_t *we) 332{ 333 334 if (we == NULL) 335 return; 336 free(we->we_wordv); 337 free(we->we_strings); 338 we->we_wordv = NULL; 339 we->we_strings = NULL; 340 we->we_nbytes = 0; 341 we->we_wordc = 0; 342} 343