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 44 static int we_askshell(const char *, wordexp_t *, int); 45 static 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 */ 54 int 55 wordexp(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 78 static size_t 79 we_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 */ 102 static int 103 we_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 (pipe(pdes) < 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 int devnull; 143 char *cmd; 144 145 (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL); 146 _close(pdes[0]); 147 if (_dup2(pdes[1], STDOUT_FILENO) < 0) 148 _exit(1); 149 _close(pdes[1]); 150 if (asprintf(&cmd, "wordexp %s\n", words) < 0) 151 _exit(1); 152 if ((flags & WRDE_SHOWERR) == 0) { 153 if ((devnull = _open(_PATH_DEVNULL, O_RDWR, 0666)) < 0) 154 _exit(1); 155 if (_dup2(devnull, STDERR_FILENO) < 0) 156 _exit(1); 157 _close(devnull); 158 } 159 execl(_PATH_BSHELL, "sh", flags & WRDE_UNDEF ? "-u" : "+u", 160 "-c", cmd, (char *)NULL); 161 _exit(1); 162 } 163 164 /* 165 * We are the parent; read the output of the shell wordexp function, 166 * which is a 32-bit hexadecimal word count, a 32-bit hexadecimal 167 * byte count (not including terminating null bytes), followed by 168 * the expanded words separated by nulls. 169 */ 170 _close(pdes[1]); 171 if (we_read_fully(pdes[0], wbuf, 8) != 8 || 172 we_read_fully(pdes[0], bbuf, 8) != 8) { 173 error = flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX; 174 serrno = errno; 175 goto cleanup; 176 } 177 wbuf[8] = bbuf[8] = '\0'; 178 nwords = strtol(wbuf, NULL, 16); 179 nbytes = strtol(bbuf, NULL, 16) + nwords; 180 181 /* 182 * Allocate or reallocate (when flags & WRDE_APPEND) the word vector 183 * and string storage buffers for the expanded words we're about to 184 * read from the child. 185 */ 186 sofs = we->we_nbytes; 187 vofs = we->we_wordc; 188 if ((flags & (WRDE_DOOFFS|WRDE_APPEND)) == (WRDE_DOOFFS|WRDE_APPEND)) 189 vofs += we->we_offs; 190 we->we_wordc += nwords; 191 we->we_nbytes += nbytes; 192 if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 + 193 (flags & WRDE_DOOFFS ? we->we_offs : 0)) * 194 sizeof(char *))) == NULL) { 195 error = WRDE_NOSPACE; 196 goto cleanup; 197 } 198 we->we_wordv = nwv; 199 if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) { 200 error = WRDE_NOSPACE; 201 goto cleanup; 202 } 203 for (i = 0; i < vofs; i++) 204 if (we->we_wordv[i] != NULL) 205 we->we_wordv[i] += nstrings - we->we_strings; 206 we->we_strings = nstrings; 207 208 if (we_read_fully(pdes[0], we->we_strings + sofs, nbytes) != nbytes) { 209 error = flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX; 210 serrno = errno; 211 goto cleanup; 212 } 213 214 error = 0; 215 cleanup: 216 _close(pdes[0]); 217 do 218 wpid = _waitpid(pid, &status, 0); 219 while (wpid < 0 && errno == EINTR); 220 (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL); 221 if (error != 0) { 222 errno = serrno; 223 return (error); 224 } 225 if (wpid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) 226 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 227 228 /* 229 * Break the null-terminated expanded word strings out into 230 * the vector. 231 */ 232 if (vofs == 0 && flags & WRDE_DOOFFS) 233 while (vofs < we->we_offs) 234 we->we_wordv[vofs++] = NULL; 235 p = we->we_strings + sofs; 236 while (nwords-- != 0) { 237 we->we_wordv[vofs++] = p; 238 if ((np = memchr(p, '\0', nbytes)) == NULL) 239 return (WRDE_NOSPACE); /* XXX */ 240 nbytes -= np - p + 1; 241 p = np + 1; 242 } 243 we->we_wordv[vofs] = NULL; 244 245 return (0); 246 } 247 248 /* 249 * we_check -- 250 * Check that the string contains none of the following unquoted 251 * special characters: <newline> |&;<>(){} 252 * or command substitutions when WRDE_NOCMD is set in flags. 253 */ 254 static int 255 we_check(const char *words, int flags) 256 { 257 char c; 258 int dquote, level, quote, squote; 259 260 quote = squote = dquote = 0; 261 while ((c = *words++) != '\0') { 262 switch (c) { 263 case '\\': 264 quote ^= 1; 265 continue; 266 case '\'': 267 if (quote + dquote == 0) 268 squote ^= 1; 269 break; 270 case '"': 271 if (quote + squote == 0) 272 dquote ^= 1; 273 break; 274 case '`': 275 if (quote + squote == 0 && flags & WRDE_NOCMD) 276 return (WRDE_CMDSUB); 277 while ((c = *words++) != '\0' && c != '`') 278 if (c == '\\' && (c = *words++) == '\0') 279 break; 280 if (c == '\0') 281 return (WRDE_SYNTAX); 282 break; 283 case '|': case '&': case ';': case '<': case '>': 284 case '{': case '}': case '(': case ')': case '\n': 285 if (quote + squote + dquote == 0) 286 return (WRDE_BADCHAR); 287 break; 288 case '$': 289 if ((c = *words++) == '\0') 290 break; 291 else if (quote + squote == 0 && c == '(') { 292 if (flags & WRDE_NOCMD && *words != '(') 293 return (WRDE_CMDSUB); 294 level = 1; 295 while ((c = *words++) != '\0') { 296 if (c == '\\') { 297 if ((c = *words++) == '\0') 298 break; 299 } else if (c == '(') 300 level++; 301 else if (c == ')' && --level == 0) 302 break; 303 } 304 if (c == '\0' || level != 0) 305 return (WRDE_SYNTAX); 306 } else if (quote + squote == 0 && c == '{') { 307 level = 1; 308 while ((c = *words++) != '\0') { 309 if (c == '\\') { 310 if ((c = *words++) == '\0') 311 break; 312 } else if (c == '{') 313 level++; 314 else if (c == '}' && --level == 0) 315 break; 316 } 317 if (c == '\0' || level != 0) 318 return (WRDE_SYNTAX); 319 } else 320 --words; 321 break; 322 default: 323 break; 324 } 325 quote = 0; 326 } 327 if (quote + squote + dquote != 0) 328 return (WRDE_SYNTAX); 329 330 return (0); 331 } 332 333 /* 334 * wordfree -- 335 * Free the result of wordexp(). See wordexp(3). 336 * 337 * Specified by IEEE Std. 1003.1-2001. 338 */ 339 void 340 wordfree(wordexp_t *we) 341 { 342 343 if (we == NULL) 344 return; 345 free(we->we_wordv); 346 free(we->we_strings); 347 we->we_wordv = NULL; 348 we->we_strings = NULL; 349 we->we_nbytes = 0; 350 we->we_wordc = 0; 351 } 352