1 /* $NetBSD: wordexp.c,v 1.4 2024/01/20 14:52:47 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 #include "extern.h" 42 43 #if defined(LIBC_SCCS) && !defined(lint) 44 #if 0 45 __FBSDID("$FreeBSD: /repoman/r/ncvs/src/lib/libc/gen/wordexp.c,v 1.5 2004/04/09 11:32:32 tjr Exp $"); 46 #else 47 __RCSID("$NetBSD: wordexp.c,v 1.4 2024/01/20 14:52:47 christos Exp $"); 48 #endif 49 #endif /* LIBC_SCCS and not lint */ 50 51 static int we_askshell(const char *, wordexp_t *, int); 52 static int we_check(const char *, int); 53 54 /* 55 * wordexp -- 56 * Perform shell word expansion on `words' and place the resulting list 57 * of words in `we'. See wordexp(3). 58 * 59 */ 60 int 61 wordexp(const char * __restrict words, wordexp_t * __restrict we, int flags) 62 { 63 int error; 64 65 _DIAGASSERT(we != NULL); 66 _DIAGASSERT(words != NULL); 67 if (flags & WRDE_REUSE) 68 wordfree(we); 69 if ((flags & WRDE_APPEND) == 0) { 70 we->we_wordc = 0; 71 we->we_wordv = NULL; 72 we->we_strings = NULL; 73 we->we_nbytes = 0; 74 } 75 if ((error = we_check(words, flags)) != 0) { 76 wordfree(we); 77 return (error); 78 } 79 if ((error = we_askshell(words, we, flags)) != 0) { 80 wordfree(we); 81 return (error); 82 } 83 return (0); 84 } 85 86 /* 87 * we_askshell -- 88 * Use the `wordexp' /bin/sh builtin function to do most of the work 89 * in expanding the word string. This function is complicated by 90 * memory management. 91 */ 92 static int 93 we_askshell(const char *words, wordexp_t *we, int flags) 94 { 95 int pdes[2]; /* Pipe to child */ 96 size_t nwords, nbytes; /* Number of words, bytes from child */ 97 int i; /* Handy integer */ 98 unsigned int ui; /* For array iteration */ 99 size_t sofs; /* Offset into we->we_strings */ 100 size_t vofs; /* Offset into we->we_wordv */ 101 pid_t pid; /* Process ID of child */ 102 int status; /* Child exit status */ 103 const char *ifs; /* IFS env. var. */ 104 char *np, *p; /* Handy pointers */ 105 char *nstrings; /* Temporary for realloc() */ 106 char **nwv; /* Temporary for realloc() */ 107 FILE *fp; /* Stream to read pipe */ 108 char *cmd; 109 110 if ((ifs = getenv("IFS")) == NULL) 111 ifs = " \t\n"; 112 if (asprintf(&cmd, "wordexp%c%s\n", *ifs, words) < 0) 113 return (WRDE_NOSPACE); 114 if (pipe(pdes) < 0) { 115 free(cmd); 116 return (WRDE_ERRNO); 117 } 118 if ((fp = fdopen(pdes[0], "r")) == NULL) { 119 free(cmd); 120 return (WRDE_ERRNO); 121 } 122 if ((pid = fork()) < 0) { 123 free(cmd); 124 fclose(fp); 125 close(pdes[1]); 126 return (WRDE_ERRNO); 127 } 128 else if (pid == 0) { 129 /* 130 * We are the child; just get /bin/sh to run the wordexp 131 * builtin on `words'. 132 */ 133 int devnull; 134 135 close(pdes[0]); 136 if (pdes[1] != STDOUT_FILENO) { 137 if (dup2(pdes[1], STDOUT_FILENO) < 0) 138 _exit(1); 139 close(pdes[1]); 140 } 141 if ((flags & WRDE_SHOWERR) == 0) { 142 if ((devnull = open(_PATH_DEVNULL, O_RDWR, 0666)) < 0) 143 _exit(1); 144 if (dup2(devnull, STDERR_FILENO) < 0) 145 _exit(1); 146 close(devnull); 147 } 148 execle(_PATH_BSHELL, "sh", flags & WRDE_UNDEF ? "-u" : "+u", 149 "-c", cmd, (char *)NULL, environ); 150 _exit(1); 151 } 152 153 /* 154 * We are the parent; read the output of the shell wordexp function, 155 * which is a decimal word count, an null, a decimal byte count, 156 * (not including terminating null bytes), a null and then followed 157 * by the expanded words separated by nulls. 158 */ 159 free(cmd); 160 close(pdes[1]); 161 /* read the word count */ 162 nwords = 0; 163 while ((i = getc(fp)) != EOF) { 164 if (i == '\0') 165 break; 166 nwords *= 10; 167 nwords += (i - '0'); 168 } 169 /* read the byte count */ 170 nbytes = 0; 171 while ((i = getc(fp)) != EOF) { 172 if (i == '\0') 173 break; 174 nbytes *= 10; 175 nbytes += (i - '0'); 176 } 177 if (i == EOF) { 178 fclose(fp); 179 waitpid(pid, &status, 0); 180 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 181 } 182 nbytes += nwords; 183 184 /* 185 * Allocate or reallocate (when flags & WRDE_APPEND) the word vector 186 * and string storage buffers for the expanded words we're about to 187 * read from the child. 188 */ 189 sofs = we->we_nbytes; 190 vofs = we->we_wordc; 191 if ((flags & (WRDE_DOOFFS|WRDE_APPEND)) == (WRDE_DOOFFS|WRDE_APPEND)) 192 vofs += we->we_offs; 193 we->we_wordc += nwords; 194 we->we_nbytes += nbytes; 195 if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 + 196 (flags & WRDE_DOOFFS ? we->we_offs : 0)) * 197 sizeof(char *))) == NULL) { 198 fclose(fp); 199 waitpid(pid, &status, 0); 200 return (WRDE_NOSPACE); 201 } 202 we->we_wordv = nwv; 203 if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) { 204 fclose(fp); 205 waitpid(pid, &status, 0); 206 return (WRDE_NOSPACE); 207 } 208 for (ui = 0; ui < vofs; ui++) 209 if (we->we_wordv[ui] != NULL) 210 we->we_wordv[ui] += nstrings - we->we_strings; 211 we->we_strings = nstrings; 212 213 if (fread(we->we_strings + sofs, sizeof(char), nbytes, fp) != nbytes) { 214 fclose(fp); 215 waitpid(pid, &status, 0); 216 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 217 } 218 219 if (waitpid(pid, &status, 0) < 0 || !WIFEXITED(status) || 220 WEXITSTATUS(status) != 0) { 221 fclose(fp); 222 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 223 } 224 fclose(fp); 225 226 /* 227 * Break the null-terminated expanded word strings out into 228 * the vector. 229 */ 230 if (vofs == 0 && flags & WRDE_DOOFFS) 231 while (vofs < we->we_offs) 232 we->we_wordv[vofs++] = NULL; 233 p = we->we_strings + sofs; 234 while (nwords-- != 0) { 235 we->we_wordv[vofs++] = p; 236 if ((np = memchr(p, '\0', nbytes)) == NULL) 237 return (WRDE_NOSPACE); /* XXX */ 238 nbytes -= np - p + 1; 239 p = np + 1; 240 } 241 we->we_wordv[vofs] = NULL; 242 243 return (0); 244 } 245 246 /* 247 * we_check -- 248 * Check that the string contains none of the following unquoted 249 * special characters: <newline> |&;<>(){} 250 * or command substitutions when WRDE_NOCMD is set in flags. 251 */ 252 static int 253 we_check(const char *words, int flags) 254 { 255 char c; 256 int dquote, level, quote, squote; 257 258 quote = squote = dquote = 0; 259 while ((c = *words++) != '\0') { 260 switch (c) { 261 case '\\': 262 quote ^= 1; 263 continue; 264 case '\'': 265 if (quote + dquote == 0) 266 squote ^= 1; 267 break; 268 case '"': 269 if (quote + squote == 0) 270 dquote ^= 1; 271 break; 272 case '`': 273 if (quote + squote == 0 && flags & WRDE_NOCMD) 274 return (WRDE_CMDSUB); 275 while ((c = *words++) != '\0' && c != '`') 276 if (c == '\\' && (c = *words++) == '\0') 277 break; 278 if (c == '\0') 279 return (WRDE_SYNTAX); 280 break; 281 case '|': case '&': case ';': case '<': case '>': 282 case '{': case '}': case '(': case ')': case '\n': 283 if (quote + squote + dquote == 0) 284 return (WRDE_BADCHAR); 285 break; 286 case '$': 287 if ((c = *words++) == '\0') 288 break; 289 else if (quote + squote == 0 && c == '(') { 290 if (flags & WRDE_NOCMD && *words != '(') 291 return (WRDE_CMDSUB); 292 level = 1; 293 while ((c = *words++) != '\0') { 294 if (c == '\\') { 295 if ((c = *words++) == '\0') 296 break; 297 } else if (c == '(') 298 level++; 299 else if (c == ')' && --level == 0) 300 break; 301 } 302 if (c == '\0' || level != 0) 303 return (WRDE_SYNTAX); 304 } else if (quote + squote == 0 && c == '{') { 305 level = 1; 306 while ((c = *words++) != '\0') { 307 if (c == '\\') { 308 if ((c = *words++) == '\0') 309 break; 310 } else if (c == '{') 311 level++; 312 else if (c == '}' && --level == 0) 313 break; 314 } 315 if (c == '\0' || level != 0) 316 return (WRDE_SYNTAX); 317 } else 318 c = *--words; 319 break; 320 default: 321 break; 322 } 323 quote = 0; 324 } 325 if (quote + squote + dquote != 0) 326 return (WRDE_SYNTAX); 327 328 return (0); 329 } 330 331 /* 332 * wordfree -- 333 * Free the result of wordexp(). See wordexp(3). 334 * 335 */ 336 void 337 wordfree(wordexp_t *we) 338 { 339 _DIAGASSERT(we != NULL); 340 free(we->we_wordv); 341 free(we->we_strings); 342 we->we_wordv = NULL; 343 we->we_strings = NULL; 344 we->we_nbytes = 0; 345 we->we_wordc = 0; 346 } 347
Indexes created Sat Sep 20 22:09:52 GMT 2025