wordexp.c revision 1.2
1 /* $NetBSD: wordexp.c,v 1.2 2005/11/29 03:11:59 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2002 Tim J. Robbins. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include "namespace.h" 30 #include <sys/cdefs.h> 31 #include <sys/types.h> 32 #include <assert.h> 33 #include <sys/wait.h> 34 #include <fcntl.h> 35 #include <paths.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <unistd.h> 40 #include <wordexp.h> 41 42 #if defined(LIBC_SCCS) && !defined(lint) 43 #if 0 44 __FBSDID("$FreeBSD: /repoman/r/ncvs/src/lib/libc/gen/wordexp.c,v 1.5 2004/04/09 11:32:32 tjr Exp $"); 45 #else 46 __RCSID("$NetBSD: wordexp.c,v 1.2 2005/11/29 03:11:59 christos Exp $"); 47 #endif 48 #endif /* LIBC_SCCS and not lint */ 49 50 static int we_askshell(const char *, wordexp_t *, int); 51 static int we_check(const char *, int); 52 53 /* 54 * wordexp -- 55 * Perform shell word expansion on `words' and place the resulting list 56 * of words in `we'. See wordexp(3). 57 * 58 */ 59 int 60 wordexp(const char * __restrict words, wordexp_t * __restrict we, int flags) 61 { 62 int error; 63 64 _DIAGASSERT(we != NULL); 65 _DIAGASSERT(words != NULL); 66 if (flags & WRDE_REUSE) 67 wordfree(we); 68 if ((flags & WRDE_APPEND) == 0) { 69 we->we_wordc = 0; 70 we->we_wordv = NULL; 71 we->we_strings = NULL; 72 we->we_nbytes = 0; 73 } 74 if ((error = we_check(words, flags)) != 0) { 75 wordfree(we); 76 return (error); 77 } 78 if ((error = we_askshell(words, we, flags)) != 0) { 79 wordfree(we); 80 return (error); 81 } 82 return (0); 83 } 84 85 /* 86 * we_askshell -- 87 * Use the `wordexp' /bin/sh builtin function to do most of the work 88 * in expanding the word string. This function is complicated by 89 * memory management. 90 */ 91 static int 92 we_askshell(const char *words, wordexp_t *we, int flags) 93 { 94 int pdes[2]; /* Pipe to child */ 95 size_t nwords, nbytes; /* Number of words, bytes from child */ 96 int i; /* Handy integer */ 97 size_t sofs; /* Offset into we->we_strings */ 98 size_t vofs; /* Offset into we->we_wordv */ 99 pid_t pid; /* Process ID of child */ 100 int status; /* Child exit status */ 101 const char *ifs; /* IFS env. var. */ 102 char *np, *p; /* Handy pointers */ 103 char *nstrings; /* Temporary for realloc() */ 104 char **nwv; /* Temporary for realloc() */ 105 FILE *fp; /* Stream to read pipe */ 106 extern char **environ; 107 char *cmd; 108 109 if ((ifs = getenv("IFS")) == NULL) 110 ifs = " \t\n"; 111 if (asprintf(&cmd, "wordexp%c%s\n", *ifs, words) < 0) 112 return (WRDE_NOSPACE); 113 if (pipe(pdes) < 0) { 114 free(cmd); 115 return (WRDE_ERRNO); 116 } 117 if ((fp = fdopen(pdes[0], "r")) == NULL) { 118 free(cmd); 119 return (WRDE_ERRNO); 120 } 121 if ((pid = fork()) < 0) { 122 free(cmd); 123 fclose(fp); 124 close(pdes[1]); 125 return (WRDE_ERRNO); 126 } 127 else if (pid == 0) { 128 /* 129 * We are the child; just get /bin/sh to run the wordexp 130 * builtin on `words'. 131 */ 132 int devnull; 133 134 close(pdes[0]); 135 if (pdes[1] != STDOUT_FILENO) { 136 if (dup2(pdes[1], STDOUT_FILENO) < 0) 137 _exit(1); 138 close(pdes[1]); 139 } 140 if ((flags & WRDE_SHOWERR) == 0) { 141 if ((devnull = open(_PATH_DEVNULL, O_RDWR, 0666)) < 0) 142 _exit(1); 143 if (dup2(devnull, STDERR_FILENO) < 0) 144 _exit(1); 145 close(devnull); 146 } 147 execle(_PATH_BSHELL, "sh", flags & WRDE_UNDEF ? "-u" : "+u", 148 "-c", cmd, (char *)NULL, environ); 149 _exit(1); 150 } 151 152 /* 153 * We are the parent; read the output of the shell wordexp function, 154 * which is a decimal word count, an null, a decimal byte count, 155 * (not including terminating null bytes), a null and then followed 156 * by the expanded words separated by nulls. 157 */ 158 free(cmd); 159 close(pdes[1]); 160 /* read the word count */ 161 nwords = 0; 162 while ((i = getc(fp)) != EOF) { 163 if (i == '\0') 164 break; 165 nwords *= 10; 166 nwords += (i - '0'); 167 } 168 /* read the byte count */ 169 nbytes = 0; 170 while ((i = getc(fp)) != EOF) { 171 if (i == '\0') 172 break; 173 nbytes *= 10; 174 nbytes += (i - '0'); 175 } 176 if (i == EOF) { 177 fclose(fp); 178 waitpid(pid, &status, 0); 179 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 180 } 181 nbytes += nwords; 182 183 /* 184 * Allocate or reallocate (when flags & WRDE_APPEND) the word vector 185 * and string storage buffers for the expanded words we're about to 186 * read from the child. 187 */ 188 sofs = we->we_nbytes; 189 vofs = we->we_wordc; 190 if ((flags & (WRDE_DOOFFS|WRDE_APPEND)) == (WRDE_DOOFFS|WRDE_APPEND)) 191 vofs += we->we_offs; 192 we->we_wordc += nwords; 193 we->we_nbytes += nbytes; 194 if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 + 195 (flags & WRDE_DOOFFS ? we->we_offs : 0)) * 196 sizeof(char *))) == NULL) { 197 fclose(fp); 198 waitpid(pid, &status, 0); 199 return (WRDE_NOSPACE); 200 } 201 we->we_wordv = nwv; 202 if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) { 203 fclose(fp); 204 waitpid(pid, &status, 0); 205 return (WRDE_NOSPACE); 206 } 207 for (i = 0; i < vofs; i++) 208 if (we->we_wordv[i] != NULL) 209 we->we_wordv[i] += nstrings - we->we_strings; 210 we->we_strings = nstrings; 211 212 if (fread(we->we_strings + sofs, sizeof(char), nbytes, fp) != nbytes) { 213 fclose(fp); 214 waitpid(pid, &status, 0); 215 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 216 } 217 218 if (waitpid(pid, &status, 0) < 0 || !WIFEXITED(status) || 219 WEXITSTATUS(status) != 0) { 220 fclose(fp); 221 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 222 } 223 fclose(fp); 224 225 /* 226 * Break the null-terminated expanded word strings out into 227 * the vector. 228 */ 229 if (vofs == 0 && flags & WRDE_DOOFFS) 230 while (vofs < we->we_offs) 231 we->we_wordv[vofs++] = NULL; 232 p = we->we_strings + sofs; 233 while (nwords-- != 0) { 234 we->we_wordv[vofs++] = p; 235 if ((np = memchr(p, '\0', nbytes)) == NULL) 236 return (WRDE_NOSPACE); /* XXX */ 237 nbytes -= np - p + 1; 238 p = np + 1; 239 } 240 we->we_wordv[vofs] = NULL; 241 242 return (0); 243 } 244 245 /* 246 * we_check -- 247 * Check that the string contains none of the following unquoted 248 * special characters: <newline> |&;<>(){} 249 * or command substitutions when WRDE_NOCMD is set in flags. 250 */ 251 static int 252 we_check(const char *words, int flags) 253 { 254 char c; 255 int dquote, level, quote, squote; 256 257 quote = squote = dquote = 0; 258 while ((c = *words++) != '\0') { 259 switch (c) { 260 case '\\': 261 quote ^= 1; 262 continue; 263 case '\'': 264 if (quote + dquote == 0) 265 squote ^= 1; 266 break; 267 case '"': 268 if (quote + squote == 0) 269 dquote ^= 1; 270 break; 271 case '`': 272 if (quote + squote == 0 && flags & WRDE_NOCMD) 273 return (WRDE_CMDSUB); 274 while ((c = *words++) != '\0' && c != '`') 275 if (c == '\\' && (c = *words++) == '\0') 276 break; 277 if (c == '\0') 278 return (WRDE_SYNTAX); 279 break; 280 case '|': case '&': case ';': case '<': case '>': 281 case '{': case '}': case '(': case ')': case '\n': 282 if (quote + squote + dquote == 0) 283 return (WRDE_BADCHAR); 284 break; 285 case '$': 286 if ((c = *words++) == '\0') 287 break; 288 else if (quote + squote == 0 && c == '(') { 289 if (flags & WRDE_NOCMD && *words != '(') 290 return (WRDE_CMDSUB); 291 level = 1; 292 while ((c = *words++) != '\0') { 293 if (c == '\\') { 294 if ((c = *words++) == '\0') 295 break; 296 } else if (c == '(') 297 level++; 298 else if (c == ')' && --level == 0) 299 break; 300 } 301 if (c == '\0' || level != 0) 302 return (WRDE_SYNTAX); 303 } else if (quote + squote == 0 && c == '{') { 304 level = 1; 305 while ((c = *words++) != '\0') { 306 if (c == '\\') { 307 if ((c = *words++) == '\0') 308 break; 309 } else if (c == '{') 310 level++; 311 else if (c == '}' && --level == 0) 312 break; 313 } 314 if (c == '\0' || level != 0) 315 return (WRDE_SYNTAX); 316 } else 317 c = *--words; 318 break; 319 default: 320 break; 321 } 322 quote = 0; 323 } 324 if (quote + squote + dquote != 0) 325 return (WRDE_SYNTAX); 326 327 return (0); 328 } 329 330 /* 331 * wordfree -- 332 * Free the result of wordexp(). See wordexp(3). 333 * 334 */ 335 void 336 wordfree(wordexp_t *we) 337 { 338 _DIAGASSERT(we != NULL); 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
Indexes created Thu Sep 25 08:09:54 GMT 2025