1 /* 2 * subst.c --- substitution program 3 * 4 * Subst is used as a quicky program to do @ substitutions 5 * 6 */ 7 8 #include <stdio.h> 9 #include <errno.h> 10 #include <stdlib.h> 11 #include <unistd.h> 12 #include <string.h> 13 #include <ctype.h> 14 #include <sys/types.h> 15 #include <sys/stat.h> 16 #include <time.h> 17 #include <utime.h> 18 19 #ifdef HAVE_GETOPT_H 20 #include <getopt.h> 21 #else 22 extern char *optarg; 23 extern int optind; 24 #endif 25 26 27 struct subst_entry { 28 char *name; 29 char *value; 30 struct subst_entry *next; 31 }; 32 33 static struct subst_entry *subst_table = 0; 34 35 static int add_subst(char *name, char *value) 36 { 37 struct subst_entry *ent = 0; 38 39 ent = (struct subst_entry *) malloc(sizeof(struct subst_entry)); 40 if (!ent) 41 goto fail; 42 ent->name = (char *) malloc(strlen(name)+1); 43 if (!ent->name) 44 goto fail; 45 ent->value = (char *) malloc(strlen(value)+1); 46 if (!ent->value) 47 goto fail; 48 strcpy(ent->name, name); 49 strcpy(ent->value, value); 50 ent->next = subst_table; 51 subst_table = ent; 52 return 0; 53 fail: 54 if (ent) { 55 free(ent->name); 56 free(ent); 57 } 58 return ENOMEM; 59 } 60 61 static struct subst_entry *fetch_subst_entry(char *name) 62 { 63 struct subst_entry *ent; 64 65 for (ent = subst_table; ent; ent = ent->next) { 66 if (strcmp(name, ent->name) == 0) 67 break; 68 } 69 return ent; 70 } 71 72 /* 73 * Given the starting and ending position of the replacement name, 74 * check to see if it is valid, and pull it out if it is. 75 */ 76 static char *get_subst_symbol(const char *begin, size_t len, char prefix) 77 { 78 static char replace_name[128]; 79 char *cp, *start; 80 81 start = replace_name; 82 if (prefix) 83 *start++ = prefix; 84 85 if (len > sizeof(replace_name)-2) 86 return NULL; 87 memcpy(start, begin, len); 88 start[len] = 0; 89 90 /* 91 * The substitution variable must all be in the of [0-9A-Za-z_]. 92 * If it isn't, this must be an invalid symbol name. 93 */ 94 for (cp = start; *cp; cp++) { 95 if (!(*cp >= 'a' && *cp <= 'z') && 96 !(*cp >= 'A' && *cp <= 'Z') && 97 !(*cp >= '0' && *cp <= '9') && 98 !(*cp == '_')) 99 return NULL; 100 } 101 return (replace_name); 102 } 103 104 static void replace_string(char *begin, char *end, char *newstr) 105 { 106 int replace_len, len; 107 108 replace_len = strlen(newstr); 109 len = end - begin; 110 if (replace_len == 0) 111 memmove(begin, end+1, strlen(end)+1); 112 else if (replace_len != len+1) 113 memmove(end+(replace_len-len-1), end, 114 strlen(end)+1); 115 memcpy(begin, newstr, replace_len); 116 } 117 118 static void substitute_line(char *line) 119 { 120 char *ptr, *name_ptr, *end_ptr; 121 struct subst_entry *ent; 122 char *replace_name; 123 size_t len; 124 125 /* 126 * Expand all @FOO@ substitutions 127 */ 128 ptr = line; 129 while (ptr) { 130 name_ptr = strchr(ptr, '@'); 131 if (!name_ptr) 132 break; /* No more */ 133 if (*(++name_ptr) == '@') { 134 /* 135 * Handle tytso@@mit.edu --> tytso (at) mit.edu 136 */ 137 memmove(name_ptr-1, name_ptr, strlen(name_ptr)+1); 138 ptr = name_ptr+1; 139 continue; 140 } 141 end_ptr = strchr(name_ptr, '@'); 142 if (!end_ptr) 143 break; 144 len = end_ptr - name_ptr; 145 replace_name = get_subst_symbol(name_ptr, len, 0); 146 if (!replace_name) { 147 ptr = name_ptr; 148 continue; 149 } 150 ent = fetch_subst_entry(replace_name); 151 if (!ent) { 152 fprintf(stderr, "Unfound expansion: '%s'\n", 153 replace_name); 154 ptr = end_ptr + 1; 155 continue; 156 } 157 #if 0 158 fprintf(stderr, "Replace name = '%s' with '%s'\n", 159 replace_name, ent->value); 160 #endif 161 ptr = name_ptr-1; 162 replace_string(ptr, end_ptr, ent->value); 163 if ((ent->value[0] == '@') && 164 (strlen(replace_name) == strlen(ent->value)-2) && 165 !strncmp(replace_name, ent->value+1, 166 strlen(ent->value)-2)) 167 /* avoid an infinite loop */ 168 ptr += strlen(ent->value); 169 } 170 /* 171 * Now do a second pass to expand ${FOO} 172 */ 173 ptr = line; 174 while (ptr) { 175 name_ptr = strchr(ptr, '$'); 176 if (!name_ptr) 177 break; /* No more */ 178 if (*(++name_ptr) != '{') { 179 ptr = name_ptr; 180 continue; 181 } 182 name_ptr++; 183 end_ptr = strchr(name_ptr, '}'); 184 if (!end_ptr) 185 break; 186 len = end_ptr - name_ptr; 187 replace_name = get_subst_symbol(name_ptr, len, '$'); 188 if (!replace_name) { 189 ptr = name_ptr; 190 continue; 191 } 192 ent = fetch_subst_entry(replace_name); 193 if (!ent) { 194 ptr = end_ptr + 1; 195 continue; 196 } 197 #if 0 198 fprintf(stderr, "Replace name = '%s' with '%s'\n", 199 replace_name, ent->value); 200 #endif 201 ptr = name_ptr-2; 202 replace_string(ptr, end_ptr, ent->value); 203 } 204 } 205 206 static void parse_config_file(FILE *f) 207 { 208 char line[2048]; 209 char *cp, *ptr; 210 211 while (!feof(f)) { 212 memset(line, 0, sizeof(line)); 213 if (fgets(line, sizeof(line), f) == NULL) 214 break; 215 /* 216 * Strip newlines and comments. 217 */ 218 cp = strchr(line, '\n'); 219 if (cp) 220 *cp = 0; 221 cp = strchr(line, '#'); 222 if (cp) 223 *cp = 0; 224 /* 225 * Skip trailing and leading whitespace 226 */ 227 for (cp = line + strlen(line) - 1; cp >= line; cp--) { 228 if (*cp == ' ' || *cp == '\t') 229 *cp = 0; 230 else 231 break; 232 } 233 cp = line; 234 while (*cp && isspace(*cp)) 235 cp++; 236 ptr = cp; 237 /* 238 * Skip empty lines 239 */ 240 if (*ptr == 0) 241 continue; 242 /* 243 * Ignore future extensions 244 */ 245 if (*ptr == '@') 246 continue; 247 /* 248 * Parse substitutions 249 */ 250 for (cp = ptr; *cp; cp++) 251 if (isspace(*cp)) 252 break; 253 *cp = 0; 254 for (cp++; *cp; cp++) 255 if (!isspace(*cp)) 256 break; 257 #if 0 258 printf("Substitute: '%s' for '%s'\n", ptr, cp ? cp : "<NULL>"); 259 #endif 260 add_subst(ptr, cp); 261 } 262 } 263 264 /* 265 * Return 0 if the files are different, 1 if the files are the same. 266 */ 267 static int compare_file(const char *outfn, const char *newfn) 268 { 269 FILE *old_f, *new_f; 270 char oldbuf[2048], newbuf[2048], *oldcp, *newcp; 271 int retval; 272 273 old_f = fopen(outfn, "r"); 274 if (!old_f) 275 return 0; 276 new_f = fopen(newfn, "r"); 277 if (!new_f) { 278 fclose(old_f); 279 return 0; 280 } 281 282 while (1) { 283 oldcp = fgets(oldbuf, sizeof(oldbuf), old_f); 284 newcp = fgets(newbuf, sizeof(newbuf), new_f); 285 if (!oldcp && !newcp) { 286 retval = 1; 287 break; 288 } 289 if (!oldcp || !newcp || strcmp(oldbuf, newbuf)) { 290 retval = 0; 291 break; 292 } 293 } 294 fclose(old_f); 295 fclose(new_f); 296 return retval; 297 } 298 299 300 301 int main(int argc, char **argv) 302 { 303 char line[2048]; 304 int c; 305 FILE *in, *out; 306 char *outfn = NULL, *newfn = NULL; 307 int verbose = 0; 308 int adjust_timestamp = 0; 309 struct stat stbuf; 310 struct utimbuf ut; 311 312 while ((c = getopt (argc, argv, "f:tv")) != EOF) { 313 switch (c) { 314 case 'f': 315 in = fopen(optarg, "r"); 316 if (!in) { 317 perror(optarg); 318 exit(1); 319 } 320 parse_config_file(in); 321 fclose(in); 322 break; 323 case 't': 324 adjust_timestamp++; 325 break; 326 case 'v': 327 verbose++; 328 break; 329 default: 330 fprintf(stderr, "%s: [-f config-file] [file]\n", 331 argv[0]); 332 break; 333 } 334 } 335 if (optind < argc) { 336 in = fopen(argv[optind], "r"); 337 if (!in) { 338 perror(argv[optind]); 339 exit(1); 340 } 341 optind++; 342 } else 343 in = stdin; 344 345 if (optind < argc) { 346 outfn = argv[optind]; 347 newfn = (char *) malloc(strlen(outfn)+20); 348 if (!newfn) { 349 fprintf(stderr, "Memory error! Exiting.\n"); 350 exit(1); 351 } 352 strcpy(newfn, outfn); 353 strcat(newfn, ".new"); 354 out = fopen(newfn, "w"); 355 if (!out) { 356 perror(newfn); 357 exit(1); 358 } 359 } else { 360 out = stdout; 361 outfn = 0; 362 } 363 364 while (!feof(in)) { 365 if (fgets(line, sizeof(line), in) == NULL) 366 break; 367 substitute_line(line); 368 fputs(line, out); 369 } 370 fclose(in); 371 fclose(out); 372 if (outfn) { 373 struct stat st; 374 if (compare_file(outfn, newfn)) { 375 if (verbose) 376 printf("No change, keeping %s.\n", outfn); 377 if (adjust_timestamp) { 378 if (stat(outfn, &stbuf) == 0) { 379 if (verbose) 380 printf("Updating modtime for %s\n", outfn); 381 ut.actime = stbuf.st_atime; 382 ut.modtime = time(0); 383 if (utime(outfn, &ut) < 0) 384 perror("utime"); 385 } 386 } 387 unlink(newfn); 388 } else { 389 if (verbose) 390 printf("Creating or replacing %s.\n", outfn); 391 rename(newfn, outfn); 392 } 393 /* set read-only to alert user it is a generated file */ 394 if (stat(outfn, &st) == 0) 395 chmod(outfn, st.st_mode & ~0222); 396 } 397 return (0); 398 } 399 400 401
