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 * $FreeBSD: src/lib/libc/gen/wordexp.c,v 1.6 2004/06/30 13:55:08 tjr Exp $ 27 * $DragonFly: src/lib/libc/gen/wordexp.c,v 1.1 2008/10/06 21:01:37 swildner Exp $ 28 */ 29 30 #include <sys/types.h> 31 #include <sys/wait.h> 32 #include <fcntl.h> 33 #include <paths.h> 34 #include <stdio.h> 35 #include <stdlib.h> 36 #include <string.h> 37 #include <unistd.h> 38 #include <wordexp.h> 39 40 static int we_askshell(const char *, wordexp_t *, int); 41 static int we_check(const char *, int); 42 43 /* 44 * wordexp -- 45 * Perform shell word expansion on `words' and place the resulting list 46 * of words in `we'. See wordexp(3). 47 * 48 * Specified by IEEE Std. 1003.1-2001. 49 */ 50 int 51 wordexp(const char * __restrict words, wordexp_t * __restrict we, int flags) 52 { 53 int error; 54 55 if (flags & WRDE_REUSE) 56 wordfree(we); 57 if ((flags & WRDE_APPEND) == 0) { 58 we->we_wordc = 0; 59 we->we_wordv = NULL; 60 we->we_strings = NULL; 61 we->we_nbytes = 0; 62 } 63 if ((error = we_check(words, flags)) != 0) { 64 wordfree(we); 65 return (error); 66 } 67 if ((error = we_askshell(words, we, flags)) != 0) { 68 wordfree(we); 69 return (error); 70 } 71 return (0); 72 } 73 74 /* 75 * we_askshell -- 76 * Use the `wordexp' /bin/sh builtin function to do most of the work 77 * in expanding the word string. This function is complicated by 78 * memory management. 79 */ 80 static int 81 we_askshell(const char *words, wordexp_t *we, int flags) 82 { 83 int pdes[2]; /* Pipe to child */ 84 char bbuf[9]; /* Buffer for byte count */ 85 char wbuf[9]; /* Buffer for word count */ 86 long nwords, nbytes; /* Number of words, bytes from child */ 87 long i; /* Handy integer */ 88 size_t sofs; /* Offset into we->we_strings */ 89 size_t vofs; /* Offset into we->we_wordv */ 90 pid_t pid; /* Process ID of child */ 91 int status; /* Child exit status */ 92 char *ifs; /* IFS env. var. */ 93 char *np, *p; /* Handy pointers */ 94 char *nstrings; /* Temporary for realloc() */ 95 char **nwv; /* Temporary for realloc() */ 96 97 if ((ifs = getenv("IFS")) == NULL) 98 ifs = " \t\n"; 99 100 if (pipe(pdes) < 0) 101 return (WRDE_NOSPACE); /* XXX */ 102 if ((pid = fork()) < 0) { 103 _close(pdes[0]); 104 _close(pdes[1]); 105 return (WRDE_NOSPACE); /* XXX */ 106 } 107 else if (pid == 0) { 108 /* 109 * We are the child; just get /bin/sh to run the wordexp 110 * builtin on `words'. 111 */ 112 int devnull; 113 char *cmd; 114 115 _close(pdes[0]); 116 if (_dup2(pdes[1], STDOUT_FILENO) < 0) 117 _exit(1); 118 _close(pdes[1]); 119 if (asprintf(&cmd, "wordexp%c%s\n", *ifs, words) < 0) 120 _exit(1); 121 if ((flags & WRDE_SHOWERR) == 0) { 122 if ((devnull = _open(_PATH_DEVNULL, O_RDWR, 0666)) < 0) 123 _exit(1); 124 if (_dup2(devnull, STDERR_FILENO) < 0) 125 _exit(1); 126 _close(devnull); 127 } 128 execl(_PATH_BSHELL, "sh", flags & WRDE_UNDEF ? "-u" : "+u", 129 "-c", cmd, (char *)NULL); 130 _exit(1); 131 } 132 133 /* 134 * We are the parent; read the output of the shell wordexp function, 135 * which is a 32-bit hexadecimal word count, a 32-bit hexadecimal 136 * byte count (not including terminating null bytes), followed by 137 * the expanded words separated by nulls. 138 */ 139 _close(pdes[1]); 140 if (_read(pdes[0], wbuf, 8) != 8 || _read(pdes[0], bbuf, 8) != 8) { 141 _close(pdes[0]); 142 _waitpid(pid, &status, 0); 143 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 144 } 145 wbuf[8] = bbuf[8] = '\0'; 146 nwords = strtol(wbuf, NULL, 16); 147 nbytes = strtol(bbuf, NULL, 16) + nwords; 148 149 /* 150 * Allocate or reallocate (when flags & WRDE_APPEND) the word vector 151 * and string storage buffers for the expanded words we're about to 152 * read from the child. 153 */ 154 sofs = we->we_nbytes; 155 vofs = we->we_wordc; 156 if ((flags & (WRDE_DOOFFS|WRDE_APPEND)) == (WRDE_DOOFFS|WRDE_APPEND)) 157 vofs += we->we_offs; 158 we->we_wordc += nwords; 159 we->we_nbytes += nbytes; 160 if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 + 161 (flags & WRDE_DOOFFS ? we->we_offs : 0)) * 162 sizeof(char *))) == NULL) { 163 _close(pdes[0]); 164 _waitpid(pid, &status, 0); 165 return (WRDE_NOSPACE); 166 } 167 we->we_wordv = nwv; 168 if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) { 169 _close(pdes[0]); 170 _waitpid(pid, &status, 0); 171 return (WRDE_NOSPACE); 172 } 173 for (i = 0; i < vofs; i++) 174 if (we->we_wordv[i] != NULL) 175 we->we_wordv[i] += nstrings - we->we_strings; 176 we->we_strings = nstrings; 177 178 if (_read(pdes[0], we->we_strings + sofs, nbytes) != nbytes) { 179 _close(pdes[0]); 180 _waitpid(pid, &status, 0); 181 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 182 } 183 184 if (_waitpid(pid, &status, 0) < 0 || !WIFEXITED(status) || 185 WEXITSTATUS(status) != 0) { 186 _close(pdes[0]); 187 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 188 } 189 _close(pdes[0]); 190 191 /* 192 * Break the null-terminated expanded word strings out into 193 * the vector. 194 */ 195 if (vofs == 0 && flags & WRDE_DOOFFS) 196 while (vofs < we->we_offs) 197 we->we_wordv[vofs++] = NULL; 198 p = we->we_strings + sofs; 199 while (nwords-- != 0) { 200 we->we_wordv[vofs++] = p; 201 if ((np = memchr(p, '\0', nbytes)) == NULL) 202 return (WRDE_NOSPACE); /* XXX */ 203 nbytes -= np - p + 1; 204 p = np + 1; 205 } 206 we->we_wordv[vofs] = NULL; 207 208 return (0); 209 } 210 211 /* 212 * we_check -- 213 * Check that the string contains none of the following unquoted 214 * special characters: <newline> |&;<>(){} 215 * or command substitutions when WRDE_NOCMD is set in flags. 216 */ 217 static int 218 we_check(const char *words, int flags) 219 { 220 char c; 221 int dquote, level, quote, squote; 222 223 quote = squote = dquote = 0; 224 while ((c = *words++) != '\0') { 225 switch (c) { 226 case '\\': 227 quote ^= 1; 228 continue; 229 case '\'': 230 if (quote + dquote == 0) 231 squote ^= 1; 232 break; 233 case '"': 234 if (quote + squote == 0) 235 dquote ^= 1; 236 break; 237 case '`': 238 if (quote + squote == 0 && flags & WRDE_NOCMD) 239 return (WRDE_CMDSUB); 240 while ((c = *words++) != '\0' && c != '`') 241 if (c == '\\' && (c = *words++) == '\0') 242 break; 243 if (c == '\0') 244 return (WRDE_SYNTAX); 245 break; 246 case '|': case '&': case ';': case '<': case '>': 247 case '{': case '}': case '(': case ')': case '\n': 248 if (quote + squote + dquote == 0) 249 return (WRDE_BADCHAR); 250 break; 251 case '$': 252 if ((c = *words++) == '\0') 253 break; 254 else if (quote + squote == 0 && c == '(') { 255 if (flags & WRDE_NOCMD && *words != '(') 256 return (WRDE_CMDSUB); 257 level = 1; 258 while ((c = *words++) != '\0') { 259 if (c == '\\') { 260 if ((c = *words++) == '\0') 261 break; 262 } else if (c == '(') 263 level++; 264 else if (c == ')' && --level == 0) 265 break; 266 } 267 if (c == '\0' || level != 0) 268 return (WRDE_SYNTAX); 269 } else if (quote + squote == 0 && c == '{') { 270 level = 1; 271 while ((c = *words++) != '\0') { 272 if (c == '\\') { 273 if ((c = *words++) == '\0') 274 break; 275 } else if (c == '{') 276 level++; 277 else if (c == '}' && --level == 0) 278 break; 279 } 280 if (c == '\0' || level != 0) 281 return (WRDE_SYNTAX); 282 } else 283 c = *--words; 284 break; 285 default: 286 break; 287 } 288 quote = 0; 289 } 290 if (quote + squote + dquote != 0) 291 return (WRDE_SYNTAX); 292 293 return (0); 294 } 295 296 /* 297 * wordfree -- 298 * Free the result of wordexp(). See wordexp(3). 299 * 300 * Specified by IEEE Std. 1003.1-2001. 301 */ 302 void 303 wordfree(wordexp_t *we) 304 { 305 306 if (we == NULL) 307 return; 308 free(we->we_wordv); 309 free(we->we_strings); 310 we->we_wordv = NULL; 311 we->we_strings = NULL; 312 we->we_nbytes = 0; 313 we->we_wordc = 0; 314 } 315