wordexp.c revision 108865
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 <fcntl.h> 32#include <paths.h> 33#include <stdio.h> 34#include <stdlib.h> 35#include <string.h> 36#include <unistd.h> 37#include <wordexp.h> 38#include "un-namespace.h" 39 40__FBSDID("$FreeBSD: head/lib/libc/gen/wordexp.c 108865 2003-01-07 06:07:56Z tjr $"); 41 42static int we_askshell(const char *, wordexp_t *, int); 43static int we_check(const char *, int); 44 45/* 46 * wordexp -- 47 * Perform shell word expansion on `words' and place the resulting list 48 * of words in `we'. See wordexp(3). 49 * 50 * Specified by IEEE Std. 1003.1-2001. 51 */ 52int 53wordexp(const char * __restrict words, wordexp_t * __restrict we, int flags) 54{ 55 int error; 56 57 if (flags & WRDE_REUSE) 58 wordfree(we); 59 if ((flags & WRDE_APPEND) == 0) { 60 we->we_wordc = 0; 61 we->we_wordv = NULL; 62 we->we_strings = NULL; 63 we->we_nbytes = 0; 64 } 65 if ((error = we_check(words, flags)) != 0) { 66 wordfree(we); 67 return (error); 68 } 69 if ((error = we_askshell(words, we, flags)) != 0) { 70 wordfree(we); 71 return (error); 72 } 73 return (0); 74} 75 76/* 77 * we_askshell -- 78 * Use the `wordexp' /bin/sh builtin function to do most of the work 79 * in expanding the word string. This function is complicated by 80 * memory management. 81 */ 82static int 83we_askshell(const char *words, wordexp_t *we, int flags) 84{ 85 int pdes[2]; /* Pipe to child */ 86 char bbuf[9]; /* Buffer for byte count */ 87 char wbuf[9]; /* Buffer for word count */ 88 long nwords, nbytes; /* Number of words, bytes from child */ 89 long i; /* Handy integer */ 90 size_t sofs; /* Offset into we->we_strings */ 91 size_t vofs; /* Offset into we->we_wordv */ 92 pid_t pid; /* Process ID of child */ 93 int status; /* Child exit status */ 94 char *ifs; /* IFS env. var. */ 95 char *np, *p; /* Handy pointers */ 96 char *nstrings; /* Temporary for realloc() */ 97 char **nwv; /* Temporary for realloc() */ 98 99 if ((ifs = getenv("IFS")) == NULL) 100 ifs = " \t\n"; 101 102 if (pipe(pdes) < 0) 103 return (WRDE_NOSPACE); /* XXX */ 104 if ((pid = fork()) < 0) { 105 _close(pdes[0]); 106 _close(pdes[1]); 107 return (WRDE_NOSPACE); /* XXX */ 108 } 109 else if (pid == 0) { 110 /* 111 * We are the child; just get /bin/sh to run the wordexp 112 * builtin on `words'. 113 */ 114 int devnull; 115 char *cmd; 116 117 _close(pdes[0]); 118 if (_dup2(pdes[1], STDOUT_FILENO) < 0) 119 _exit(1); 120 _close(pdes[1]); 121 if (asprintf(&cmd, "wordexp%c%s\n", *ifs, words) < 0) 122 _exit(1); 123 if ((flags & WRDE_SHOWERR) == 0) { 124 if ((devnull = _open(_PATH_DEVNULL, O_RDWR, 0666)) < 0) 125 _exit(1); 126 if (_dup2(devnull, STDERR_FILENO) < 0) 127 _exit(1); 128 _close(devnull); 129 } 130 execl(_PATH_BSHELL, "sh", flags & WRDE_UNDEF ? "-u" : "+u", 131 "-c", cmd, NULL); 132 _exit(1); 133 } 134 135 /* 136 * We are the parent; read the output of the shell wordexp function, 137 * which is a 32-bit hexadecimal word count, a 32-bit hexadecimal 138 * byte count (not including terminating null bytes), followed by 139 * the expanded words separated by nulls. 140 */ 141 _close(pdes[1]); 142 if (_read(pdes[0], wbuf, 8) != 8 || _read(pdes[0], bbuf, 8) != 8) { 143 _close(pdes[0]); 144 _waitpid(pid, &status, 0); 145 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 146 } 147 wbuf[8] = bbuf[8] = '\0'; 148 nwords = strtol(wbuf, NULL, 16); 149 nbytes = strtol(bbuf, NULL, 16) + nwords; 150 151 /* 152 * Allocate or reallocate (when flags & WRDE_APPEND) the word vector 153 * and string storage buffers for the expanded words we're about to 154 * read from the child. 155 */ 156 sofs = we->we_nbytes; 157 vofs = we->we_wordc; 158 if ((flags & (WRDE_DOOFS|WRDE_APPEND)) == (WRDE_DOOFS|WRDE_APPEND)) 159 vofs += we->we_offs; 160 we->we_wordc += nwords; 161 we->we_nbytes += nbytes; 162 if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 + 163 (flags & WRDE_DOOFS ? we->we_offs : 0)) * 164 sizeof(char *))) == NULL) { 165 _close(pdes[0]); 166 _waitpid(pid, &status, 0); 167 return (WRDE_NOSPACE); 168 } 169 we->we_wordv = nwv; 170 if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) { 171 _close(pdes[0]); 172 _waitpid(pid, &status, 0); 173 return (WRDE_NOSPACE); 174 } 175 for (i = 0; i < vofs; i++) 176 if (we->we_wordv[i] != NULL) 177 we->we_wordv[i] += nstrings - we->we_strings; 178 we->we_strings = nstrings; 179 180 if (_read(pdes[0], we->we_strings + sofs, nbytes) != nbytes) { 181 _close(pdes[0]); 182 _waitpid(pid, &status, 0); 183 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 184 } 185 186 if (_waitpid(pid, &status, 0) < 0 || !WIFEXITED(status) || 187 WEXITSTATUS(status) != 0) { 188 _close(pdes[0]); 189 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 190 } 191 _close(pdes[0]); 192 193 /* 194 * Break the null-terminated expanded word strings out into 195 * the vector. 196 */ 197 if (vofs == 0 && flags & WRDE_DOOFS) 198 while (vofs < we->we_offs) 199 we->we_wordv[vofs++] = NULL; 200 p = we->we_strings + sofs; 201 while (nwords-- != 0) { 202 we->we_wordv[vofs++] = p; 203 if ((np = memchr(p, '\0', nbytes)) == NULL) 204 return (WRDE_NOSPACE); /* XXX */ 205 nbytes -= np - p + 1; 206 p = np + 1; 207 } 208 we->we_wordv[vofs] = NULL; 209 210 return (0); 211} 212 213/* 214 * we_check -- 215 * Check that the string contains none of the following unquoted 216 * special characters: <newline> |&;<>(){} 217 * or command substitutions when WRDE_NOCMD is set in flags. 218 */ 219static int 220we_check(const char *words, int flags) 221{ 222 char c; 223 int dquote, level, quote, squote; 224 225 quote = squote = dquote = 0; 226 while ((c = *words++) != '\0') { 227 switch (c) { 228 case '\\': 229 quote ^= 1; 230 continue; 231 case '\'': 232 if (quote + dquote == 0) 233 squote ^= 1; 234 break; 235 case '"': 236 if (quote + squote == 0) 237 dquote ^= 1; 238 break; 239 case '`': 240 if (quote + squote == 0 && flags & WRDE_NOCMD) 241 return (WRDE_CMDSUB); 242 while ((c = *words++) != '\0' && c != '`') 243 if (c == '\\' && (c = *words++) == '\0') 244 break; 245 if (c == '\0') 246 return (WRDE_SYNTAX); 247 break; 248 case '|': case '&': case ';': case '<': case '>': 249 case '{': case '}': case '(': case ')': case '\n': 250 if (quote + squote + dquote == 0) 251 return (WRDE_BADCHAR); 252 break; 253 case '$': 254 if ((c = *words++) == '\0') 255 break; 256 else if (quote + squote == 0 && c == '(') { 257 if (flags & WRDE_NOCMD && *words != '(') 258 return (WRDE_CMDSUB); 259 level = 1; 260 while ((c = *words++) != '\0') { 261 if (c == '\\') { 262 if ((c = *words++) == '\0') 263 break; 264 } else if (c == '(') 265 level++; 266 else if (c == ')' && --level == 0) 267 break; 268 } 269 if (c == '\0' || level != 0) 270 return (WRDE_SYNTAX); 271 } else if (quote + squote == 0 && c == '{') { 272 level = 1; 273 while ((c = *words++) != '\0') { 274 if (c == '\\') { 275 if ((c = *words++) == '\0') 276 break; 277 } else if (c == '{') 278 level++; 279 else if (c == '}' && --level == 0) 280 break; 281 } 282 if (c == '\0' || level != 0) 283 return (WRDE_SYNTAX); 284 } else 285 c = *--words; 286 break; 287 default: 288 break; 289 } 290 quote = 0; 291 } 292 if (quote + squote + dquote != 0) 293 return (WRDE_SYNTAX); 294 295 return (0); 296} 297 298/* 299 * wordfree -- 300 * Free the result of wordexp(). See wordexp(3). 301 * 302 * Specified by IEEE Std. 1003.1-2001. 303 */ 304void 305wordfree(wordexp_t *we) 306{ 307 308 if (we == NULL) 309 return; 310 free(we->we_wordv); 311 free(we->we_strings); 312 we->we_wordv = NULL; 313 we->we_strings = NULL; 314 we->we_nbytes = 0; 315 we->we_wordc = 0; 316} 317