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 const char *ifs; 122 123 serrno = errno; 124 ifs = getenv("IFS"); 125 126 if (pipe2(pdes, O_CLOEXEC) < 0) 127 return (WRDE_NOSPACE); /* XXX */ 128 (void)sigemptyset(&newsigblock); 129 (void)sigaddset(&newsigblock, SIGCHLD); 130 (void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock); 131 if ((pid = fork()) < 0) { 132 serrno = errno; 133 _close(pdes[0]); 134 _close(pdes[1]); 135 (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL); 136 errno = serrno; 137 return (WRDE_NOSPACE); /* XXX */ 138 } 139 else if (pid == 0) { 140 /* 141 * We are the child; just get /bin/sh to run the wordexp 142 * builtin on `words'. 143 */ 144 (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL); 145 if ((pdes[1] != STDOUT_FILENO ? 146 _dup2(pdes[1], STDOUT_FILENO) : 147 _fcntl(pdes[1], F_SETFD, 0)) < 0) 148 _exit(1); 149 execl(_PATH_BSHELL, "sh", flags & WRDE_UNDEF ? "-u" : "+u", 150 "-c", "IFS=$1;eval \"$2\";eval \"wordexp $3\"", "", 151 ifs != NULL ? ifs : " \t\n", 152 flags & WRDE_SHOWERR ? "" : "exec 2>/dev/null", words, 153 (char *)NULL); 154 _exit(1); 155 } 156 157 /* 158 * We are the parent; read the output of the shell wordexp function, 159 * which is a 32-bit hexadecimal word count, a 32-bit hexadecimal 160 * byte count (not including terminating null bytes), followed by 161 * the expanded words separated by nulls. 162 */ 163 _close(pdes[1]); 164 if (we_read_fully(pdes[0], wbuf, 8) != 8 || 165 we_read_fully(pdes[0], bbuf, 8) != 8) { 166 error = flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX; 167 serrno = errno; 168 goto cleanup; 169 } 170 wbuf[8] = bbuf[8] = '\0'; 171 nwords = strtol(wbuf, NULL, 16); 172 nbytes = strtol(bbuf, NULL, 16) + nwords; 173 174 /* 175 * Allocate or reallocate (when flags & WRDE_APPEND) the word vector 176 * and string storage buffers for the expanded words we're about to 177 * read from the child. 178 */ 179 sofs = we->we_nbytes; 180 vofs = we->we_wordc; 181 if ((flags & (WRDE_DOOFFS|WRDE_APPEND)) == (WRDE_DOOFFS|WRDE_APPEND)) 182 vofs += we->we_offs; 183 we->we_wordc += nwords; 184 we->we_nbytes += nbytes; 185 if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 + 186 (flags & WRDE_DOOFFS ? we->we_offs : 0)) * 187 sizeof(char *))) == NULL) { 188 error = WRDE_NOSPACE; 189 goto cleanup; 190 } 191 we->we_wordv = nwv; 192 if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) { 193 error = WRDE_NOSPACE; 194 goto cleanup; 195 } 196 for (i = 0; i < vofs; i++) 197 if (we->we_wordv[i] != NULL) 198 we->we_wordv[i] += nstrings - we->we_strings; 199 we->we_strings = nstrings; 200 201 if (we_read_fully(pdes[0], we->we_strings + sofs, nbytes) != nbytes) { 202 error = flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX; 203 serrno = errno; 204 goto cleanup; 205 } 206 207 error = 0; 208 cleanup: 209 _close(pdes[0]); 210 do 211 wpid = _waitpid(pid, &status, 0); 212 while (wpid < 0 && errno == EINTR); 213 (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL); 214 if (error != 0) { 215 errno = serrno; 216 return (error); 217 } 218 if (wpid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) 219 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 220 221 /* 222 * Break the null-terminated expanded word strings out into 223 * the vector. 224 */ 225 if (vofs == 0 && flags & WRDE_DOOFFS) 226 while (vofs < we->we_offs) 227 we->we_wordv[vofs++] = NULL; 228 p = we->we_strings + sofs; 229 while (nwords-- != 0) { 230 we->we_wordv[vofs++] = p; 231 if ((np = memchr(p, '\0', nbytes)) == NULL) 232 return (WRDE_NOSPACE); /* XXX */ 233 nbytes -= np - p + 1; 234 p = np + 1; 235 } 236 we->we_wordv[vofs] = NULL; 237 238 return (0); 239 } 240 241 /* 242 * we_check -- 243 * Check that the string contains none of the following unquoted 244 * special characters: <newline> |&;<>(){} 245 * or command substitutions when WRDE_NOCMD is set in flags. 246 */ 247 static int 248 we_check(const char *words, int flags) 249 { 250 char c; 251 int dquote, level, quote, squote; 252 253 quote = squote = dquote = 0; 254 while ((c = *words++) != '\0') { 255 switch (c) { 256 case '\\': 257 if (squote == 0) 258 quote ^= 1; 259 continue; 260 case '\'': 261 if (quote + dquote == 0) 262 squote ^= 1; 263 break; 264 case '"': 265 if (quote + squote == 0) 266 dquote ^= 1; 267 break; 268 case '`': 269 if (quote + squote == 0 && flags & WRDE_NOCMD) 270 return (WRDE_CMDSUB); 271 while ((c = *words++) != '\0' && c != '`') 272 if (c == '\\' && (c = *words++) == '\0') 273 break; 274 if (c == '\0') 275 return (WRDE_SYNTAX); 276 break; 277 case '|': case '&': case ';': case '<': case '>': 278 case '{': case '}': case '(': case ')': case '\n': 279 if (quote + squote + dquote == 0) 280 return (WRDE_BADCHAR); 281 break; 282 case '$': 283 if ((c = *words++) == '\0') 284 break; 285 else if (quote + squote == 0 && c == '(') { 286 if (flags & WRDE_NOCMD && *words != '(') 287 return (WRDE_CMDSUB); 288 level = 1; 289 while ((c = *words++) != '\0') { 290 if (c == '\\') { 291 if ((c = *words++) == '\0') 292 break; 293 } else if (c == '(') 294 level++; 295 else if (c == ')' && --level == 0) 296 break; 297 } 298 if (c == '\0' || level != 0) 299 return (WRDE_SYNTAX); 300 } else if (quote + squote == 0 && c == '{') { 301 level = 1; 302 while ((c = *words++) != '\0') { 303 if (c == '\\') { 304 if ((c = *words++) == '\0') 305 break; 306 } else if (c == '{') 307 level++; 308 else if (c == '}' && --level == 0) 309 break; 310 } 311 if (c == '\0' || level != 0) 312 return (WRDE_SYNTAX); 313 } else 314 --words; 315 break; 316 default: 317 break; 318 } 319 quote = 0; 320 } 321 if (quote + squote + dquote != 0) 322 return (WRDE_SYNTAX); 323 324 return (0); 325 } 326 327 /* 328 * wordfree -- 329 * Free the result of wordexp(). See wordexp(3). 330 * 331 * Specified by IEEE Std. 1003.1-2001. 332 */ 333 void 334 wordfree(wordexp_t *we) 335 { 336 337 if (we == NULL) 338 return; 339 free(we->we_wordv); 340 free(we->we_strings); 341 we->we_wordv = NULL; 342 we->we_strings = NULL; 343 we->we_nbytes = 0; 344 we->we_wordc = 0; 345 } 346