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 */ 28 29 #include "namespace.h" 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 #include "un-namespace.h" 40 41 static int we_askshell(const char *, wordexp_t *, int); 42 static int we_check(const char *, int); 43 44 /* 45 * wordexp -- 46 * Perform shell word expansion on `words' and place the resulting list 47 * of words in `we'. See wordexp(3). 48 * 49 * Specified by IEEE Std. 1003.1-2001. 50 */ 51 int 52 wordexp(const char * __restrict words, wordexp_t * __restrict we, int flags) 53 { 54 int error; 55 56 if (flags & WRDE_REUSE) 57 wordfree(we); 58 if ((flags & WRDE_APPEND) == 0) { 59 we->we_wordc = 0; 60 we->we_wordv = NULL; 61 we->we_strings = NULL; 62 we->we_nbytes = 0; 63 } 64 if ((error = we_check(words, flags)) != 0) { 65 wordfree(we); 66 return (error); 67 } 68 if ((error = we_askshell(words, we, flags)) != 0) { 69 wordfree(we); 70 return (error); 71 } 72 return (0); 73 } 74 75 /* 76 * we_askshell -- 77 * Use the `wordexp' /bin/sh builtin function to do most of the work 78 * in expanding the word string. This function is complicated by 79 * memory management. 80 */ 81 static int 82 we_askshell(const char *words, wordexp_t *we, int flags) 83 { 84 int pdes[2]; /* Pipe to child */ 85 char bbuf[9]; /* Buffer for byte count */ 86 char wbuf[9]; /* Buffer for word count */ 87 long nwords, nbytes; /* Number of words, bytes from child */ 88 long i; /* Handy integer */ 89 size_t sofs; /* Offset into we->we_strings */ 90 size_t vofs; /* Offset into we->we_wordv */ 91 pid_t pid; /* Process ID of child */ 92 int status; /* Child exit status */ 93 char *ifs; /* IFS env. var. */ 94 char *np, *p; /* Handy pointers */ 95 char *nstrings; /* Temporary for realloc() */ 96 char **nwv; /* Temporary for realloc() */ 97 98 if ((ifs = getenv("IFS")) == NULL) 99 ifs = " \t\n"; 100 101 if (pipe(pdes) < 0) 102 return (WRDE_NOSPACE); /* XXX */ 103 if ((pid = fork()) < 0) { 104 _close(pdes[0]); 105 _close(pdes[1]); 106 return (WRDE_NOSPACE); /* XXX */ 107 } 108 else if (pid == 0) { 109 /* 110 * We are the child; just get /bin/sh to run the wordexp 111 * builtin on `words'. 112 */ 113 int devnull; 114 char *cmd; 115 116 _close(pdes[0]); 117 if (_dup2(pdes[1], STDOUT_FILENO) < 0) 118 _exit(1); 119 _close(pdes[1]); 120 if (asprintf(&cmd, "wordexp%c%s\n", *ifs, words) < 0) 121 _exit(1); 122 if ((flags & WRDE_SHOWERR) == 0) { 123 if ((devnull = _open(_PATH_DEVNULL, O_RDWR, 0666)) < 0) 124 _exit(1); 125 if (_dup2(devnull, STDERR_FILENO) < 0) 126 _exit(1); 127 _close(devnull); 128 } 129 execl(_PATH_BSHELL, "sh", flags & WRDE_UNDEF ? "-u" : "+u", 130 "-c", cmd, NULL); 131 _exit(1); 132 } 133 134 /* 135 * We are the parent; read the output of the shell wordexp function, 136 * which is a 32-bit hexadecimal word count, a 32-bit hexadecimal 137 * byte count (not including terminating null bytes), followed by 138 * the expanded words separated by nulls. 139 */ 140 _close(pdes[1]); 141 if (_read(pdes[0], wbuf, 8) != 8 || _read(pdes[0], bbuf, 8) != 8) { 142 _close(pdes[0]); 143 _waitpid(pid, &status, 0); 144 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 145 } 146 wbuf[8] = bbuf[8] = '\0'; 147 nwords = strtol(wbuf, NULL, 16); 148 nbytes = strtol(bbuf, NULL, 16) + nwords; 149 150 /* 151 * Allocate or reallocate (when flags & WRDE_APPEND) the word vector 152 * and string storage buffers for the expanded words we're about to 153 * read from the child. 154 */ 155 sofs = we->we_nbytes; 156 vofs = we->we_wordc; 157 if ((flags & (WRDE_DOOFFS|WRDE_APPEND)) == (WRDE_DOOFFS|WRDE_APPEND)) 158 vofs += we->we_offs; 159 we->we_wordc += nwords; 160 we->we_nbytes += nbytes; 161 if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 + 162 (flags & WRDE_DOOFFS ? we->we_offs : 0)) * 163 sizeof(char *))) == NULL) { 164 _close(pdes[0]); 165 _waitpid(pid, &status, 0); 166 return (WRDE_NOSPACE); 167 } 168 we->we_wordv = nwv; 169 if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) { 170 _close(pdes[0]); 171 _waitpid(pid, &status, 0); 172 return (WRDE_NOSPACE); 173 } 174 for (i = 0; i < vofs; i++) 175 if (we->we_wordv[i] != NULL) 176 we->we_wordv[i] += nstrings - we->we_strings; 177 we->we_strings = nstrings; 178 179 if (_read(pdes[0], we->we_strings + sofs, nbytes) != nbytes) { 180 _close(pdes[0]); 181 _waitpid(pid, &status, 0); 182 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 183 } 184 185 if (_waitpid(pid, &status, 0) < 0 || !WIFEXITED(status) || 186 WEXITSTATUS(status) != 0) { 187 _close(pdes[0]); 188 return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX); 189 } 190 _close(pdes[0]); 191 192 /* 193 * Break the null-terminated expanded word strings out into 194 * the vector. 195 */ 196 if (vofs == 0 && flags & WRDE_DOOFFS) 197 while (vofs < we->we_offs) 198 we->we_wordv[vofs++] = NULL; 199 p = we->we_strings + sofs; 200 while (nwords-- != 0) { 201 we->we_wordv[vofs++] = p; 202 if ((np = memchr(p, '\0', nbytes)) == NULL) 203 return (WRDE_NOSPACE); /* XXX */ 204 nbytes -= np - p + 1; 205 p = np + 1; 206 } 207 we->we_wordv[vofs] = NULL; 208 209 return (0); 210 } 211 212 /* 213 * we_check -- 214 * Check that the string contains none of the following unquoted 215 * special characters: <newline> |&;<>(){} 216 * or command substitutions when WRDE_NOCMD is set in flags. 217 */ 218 static int 219 we_check(const char *words, int flags) 220 { 221 char c; 222 int dquote, level, quote, squote; 223 224 quote = squote = dquote = 0; 225 while ((c = *words++) != '\0') { 226 switch (c) { 227 case '\\': 228 quote ^= 1; 229 continue; 230 case '\'': 231 if (quote + dquote == 0) 232 squote ^= 1; 233 break; 234 case '"': 235 if (quote + squote == 0) 236 dquote ^= 1; 237 break; 238 case '`': 239 if (quote + squote == 0 && flags & WRDE_NOCMD) 240 return (WRDE_CMDSUB); 241 while ((c = *words++) != '\0' && c != '`') 242 if (c == '\\' && (c = *words++) == '\0') 243 break; 244 if (c == '\0') 245 return (WRDE_SYNTAX); 246 break; 247 case '|': case '&': case ';': case '<': case '>': 248 case '{': case '}': case '(': case ')': case '\n': 249 if (quote + squote + dquote == 0) 250 return (WRDE_BADCHAR); 251 break; 252 case '$': 253 if ((c = *words++) == '\0') 254 break; 255 else if (quote + squote == 0 && c == '(') { 256 if (flags & WRDE_NOCMD && *words != '(') 257 return (WRDE_CMDSUB); 258 level = 1; 259 while ((c = *words++) != '\0') { 260 if (c == '\\') { 261 if ((c = *words++) == '\0') 262 break; 263 } else if (c == '(') 264 level++; 265 else if (c == ')' && --level == 0) 266 break; 267 } 268 if (c == '\0' || level != 0) 269 return (WRDE_SYNTAX); 270 } else if (quote + squote == 0 && c == '{') { 271 level = 1; 272 while ((c = *words++) != '\0') { 273 if (c == '\\') { 274 if ((c = *words++) == '\0') 275 break; 276 } else if (c == '{') 277 level++; 278 else if (c == '}' && --level == 0) 279 break; 280 } 281 if (c == '\0' || level != 0) 282 return (WRDE_SYNTAX); 283 } else 284 c = *--words; 285 break; 286 default: 287 break; 288 } 289 quote = 0; 290 } 291 if (quote + squote + dquote != 0) 292 return (WRDE_SYNTAX); 293 294 return (0); 295 } 296 297 /* 298 * wordfree -- 299 * Free the result of wordexp(). See wordexp(3). 300 * 301 * Specified by IEEE Std. 1003.1-2001. 302 */ 303 void 304 wordfree(wordexp_t *we) 305 { 306 307 if (we == NULL) 308 return; 309 free(we->we_wordv); 310 free(we->we_strings); 311 we->we_wordv = NULL; 312 we->we_strings = NULL; 313 we->we_nbytes = 0; 314 we->we_wordc = 0; 315 } 316