editors/sed.c

   1 /*
   2  * sed.c - very minimalist version of sed
   3  *
   4  * Copyright (C) 1999,2000,2001 by Lineo, inc. and Mark Whitley
   5  * Copyright (C) 1999,2000,2001 by Mark Whitley <markw@codepoet.org>
   6  * Copyright (C) 2002  Matt Kraai
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21  *
  22  */
  23
  24 /*
  25         Supported features and commands in this version of sed:
  26
  27          - comments ('#')
  28          - address matching: num|/matchstr/[,num|/matchstr/|$]command
  29          - commands: (p)rint, (d)elete, (s)ubstitue (with g & I flags)
  30          - edit commands: (a)ppend, (i)nsert, (c)hange
  31          - file commands: (r)ead
  32          - backreferences in substitution expressions (\1, \2...\9)
  33          - grouped commands: {cmd1;cmd2}
  34
  35          (Note: Specifying an address (range) to match is *optional*; commands
  36          default to the whole pattern space if no specific address match was
  37          requested.)
  38
  39         Unsupported features:
  40
  41          - transliteration (y/source-chars/dest-chars/) (use 'tr')
  42          - no pattern space hold space storing / swapping (x, etc.)
  43          - no labels / branching (: label, b, t, and friends)
  44          - and lots, lots more.
  45
  46         Reference http://www.opengroup.org/onlinepubs/007904975/utilities/sed.html
  47 */
  48
  49 #include <stdio.h>
  50 #include <unistd.h> /* for getopt() */
  51 #include <regex.h>
  52 #include <string.h> /* for strdup() */
  53 #include <errno.h>
  54 #include <ctype.h> /* for isspace() */
  55 #include <stdlib.h>
  56 #include "busybox.h"
  57
  58 /* externs */
  59 extern void xregcomp(regex_t *preg, const char *regex, int cflags);
  60 extern int optind; /* in unistd.h */
  61 extern char *optarg; /* ditto */
  62
  63 /* options */
  64 static int be_quiet = 0;
  65
  66
  67 typedef struct sed_cmd_s {
  68         /* Order by alignment requirements */
  69
  70         /* address storage */
  71         regex_t *beg_match; /* sed -e '/match/cmd' */
  72         regex_t *end_match; /* sed -e '/match/,/end_match/cmd' */
  73
  74         /* SUBSTITUTION COMMAND SPECIFIC FIELDS */
  75
  76         /* sed -e 's/sub_match/replace/' */
  77         regex_t *sub_match;
  78         char *replace;
  79
  80         /* EDIT COMMAND (a,i,c) SPECIFIC FIELDS */
  81         char *editline;
  82
  83         /* FILE COMMAND (r) SPECIFIC FIELDS */
  84         char *filename;
  85
  86         /* address storage */
  87         int beg_line; /* 'sed 1p'   0 == no begining line, apply commands to all lines */
  88         int end_line; /* 'sed 1,3p' 0 == no end line, use only beginning. -1 == $ */
  89         /* SUBSTITUTION COMMAND SPECIFIC FIELDS */
  90
  91         unsigned int num_backrefs:4; /* how many back references (\1..\9) */
  92                         /* Note:  GNU/POSIX sed does not save more than nine backrefs, so
  93                          * we only use 4 bits to hold the number */
  94         unsigned int sub_g:1; /* sed -e 's/foo/bar/g' (global) */
  95         unsigned int sub_p:2; /* sed -e 's/foo/bar/p' (print substitution) */
  96
  97         /* GENERAL FIELDS */
  98         char delimiter;     /* The delimiter used to separate regexps */
  99
 100         /* the command */
 101         char cmd; /* p,d,s (add more at your leisure :-) */
 102
 103         /* inversion flag */
 104         int invert;         /* the '!' after the address */
 105 } sed_cmd_t;
 106
 107 /* globals */
 108 static sed_cmd_t **sed_cmds = NULL; /* growable arrary holding a sequence of sed cmds */
 109 static int ncmds = 0; /* number of sed commands */
 110
 111 /*static char *cur_file = NULL;*/ /* file currently being processed XXX: do I need this? */
 112
 113 const char * const semicolon_whitespace = "; \n\r\t\v\0";
 114
 115 #ifdef CONFIG_FEATURE_CLEAN_UP
 116 static void destroy_cmd_strs(void)
 117 {
 118         if (sed_cmds == NULL)
 119                 return;
 120
 121         /* destroy all the elements in the array */
 122         while (--ncmds >= 0) {
 123
 124                 if (sed_cmds[ncmds]->beg_match) {
 125                         regfree(sed_cmds[ncmds]->beg_match);
 126                         free(sed_cmds[ncmds]->beg_match);
 127                 }
 128                 if (sed_cmds[ncmds]->end_match) {
 129                         regfree(sed_cmds[ncmds]->end_match);
 130                         free(sed_cmds[ncmds]->end_match);
 131                 }
 132                 if (sed_cmds[ncmds]->sub_match) {
 133                         regfree(sed_cmds[ncmds]->sub_match);
 134                         free(sed_cmds[ncmds]->sub_match);
 135                 }
 136                 free(sed_cmds[ncmds]->replace);
 137         }
 138
 139         /* destroy the array */
 140         free(sed_cmds);
 141         sed_cmds = NULL;
 142 }
 143 #endif
 144
 145
 146 /*
 147  * index_of_next_unescaped_regexp_delim - walks left to right through a string
 148  * beginning at a specified index and returns the index of the next regular
 149  * expression delimiter (typically a forward * slash ('/')) not preceeded by
 150  * a backslash ('\').
 151  */
 152 static int index_of_next_unescaped_regexp_delim(const char delimiter, const char *str, int idx)
 153 {
 154         int bracket = -1;
 155         int escaped = 0;
 156         char ch;
 157
 158         for ( ; (ch = str[idx]); idx++) {
 159                 if (bracket != -1) {
 160                         if (ch == ']' && !(bracket == idx - 1 ||
 161                                                                          (bracket == idx - 2 && str[idx-1] == '^')))
 162                                 bracket = -1;
 163                 } else if (escaped)
 164                         escaped = 0;
 165                 else if (ch == '\\')
 166                         escaped = 1;
 167                 else if (ch == '[')
 168                         bracket = idx;
 169                 else if (ch == delimiter)
 170                         return idx;
 171         }
 172
 173         /* if we make it to here, we've hit the end of the string */
 174         return -1;
 175 }
 176
 177 /*
 178  * returns the index in the string just past where the address ends.
 179  */
 180 static int get_address(char *delimiter, char *my_str, int *linenum, regex_t **regex)
 181 {
 182         int idx = 0;
 183         if (isdigit(my_str[idx])) {
 184                 char *endstr;
 185                 *linenum = strtol(my_str, &endstr, 10);
 186                 /* endstr shouldnt ever equal NULL */
 187                 idx = endstr - my_str;
 188         }
 189         else if (my_str[idx] == '$') {
 190                 *linenum = -1;
 191                 idx++;
 192         }
 193         else if (my_str[idx] == '/' || my_str[idx] == '\\') {
 194                 int idx_start = 1;
 195
 196                 *delimiter = '/';
 197                 if (my_str[idx] == '\\') {
 198                         idx_start++;
 199                         *delimiter = my_str[++idx];
 200                 }
 201                 idx = index_of_next_unescaped_regexp_delim(*delimiter, my_str, ++idx);
 202                 if (idx == -1) {
 203                         error_msg_and_die("unterminated match expression");
 204                 }
 205                 my_str[idx] = '\0';
 206                 *regex = (regex_t *)xmalloc(sizeof(regex_t));
 207                 xregcomp(*regex, my_str+idx_start, REG_NEWLINE);
 208                 idx++; /* so it points to the next character after the last '/' */
 209         }
 210         return idx;
 211 }
 212
 213 static int parse_subst_cmd(sed_cmd_t * const sed_cmd, const char *substr)
 214 {
 215         int oldidx, cflags = REG_NEWLINE;
 216         char *match;
 217         int idx = 0;
 218         int j;
 219
 220         /*
 221          * the string that gets passed to this function should look like this:
 222          *    s/match/replace/gIp
 223          *    ||     |        |||
 224          *    mandatory       optional
 225          *
 226          *    (all three of the '/' slashes are mandatory)
 227          */
 228
 229         /* verify that the 's' is followed by something.  That something
 230          * (typically a 'slash') is now our regexp delimiter... */
 231         if (substr[idx] == '\0')
 232                 error_msg_and_die("bad format in substitution expression");
 233         else
 234             sed_cmd->delimiter=substr[idx];
 235
 236         /* save the match string */
 237         oldidx = idx+1;
 238         idx = index_of_next_unescaped_regexp_delim(sed_cmd->delimiter, substr, ++idx);
 239         if (idx == -1)
 240                 error_msg_and_die("bad format in substitution expression");
 241         match = xstrndup(substr + oldidx, idx - oldidx);
 242
 243         /* determine the number of back references in the match string */
 244         /* Note: we compute this here rather than in the do_subst_command()
 245          * function to save processor time, at the expense of a little more memory
 246          * (4 bits) per sed_cmd */
 247
 248         /* sed_cmd->num_backrefs = 0; */ /* XXX: not needed? --apparently not */
 249         for (j = 0; match[j]; j++) {
 250                 /* GNU/POSIX sed does not save more than nine backrefs */
 251                 if (match[j] == '\\' && match[j+1] == '(' && sed_cmd->num_backrefs <= 9)
 252                         sed_cmd->num_backrefs++;
 253         }
 254
 255         /* save the replacement string */
 256         oldidx = idx+1;
 257         idx = index_of_next_unescaped_regexp_delim(sed_cmd->delimiter, substr, ++idx);
 258         if (idx == -1)
 259                 error_msg_and_die("bad format in substitution expression");
 260         sed_cmd->replace = xstrndup(substr + oldidx, idx - oldidx);
 261
 262         /* process the flags */
 263         while (substr[++idx]) {
 264                 switch (substr[idx]) {
 265                         case 'g':
 266                                 sed_cmd->sub_g = 1;
 267                                 break;
 268                         /* Hmm, i dont see the I option mentioned in the standard */
 269                         case 'I':
 270                                 cflags |= REG_ICASE;
 271                                 break;
 272                         case 'p':
 273                                 sed_cmd->sub_p = 1;
 274                                 break;
 275                         default:
 276                                 /* any whitespace or semicolon trailing after a s/// is ok */
 277                                 if (strchr(semicolon_whitespace, substr[idx]))
 278                                         goto out;
 279                                 /* else */
 280                                 error_msg_and_die("bad option in substitution expression");
 281                 }
 282         }
 283
 284 out:
 285         /* compile the match string into a regex */
 286         sed_cmd->sub_match = (regex_t *)xmalloc(sizeof(regex_t));
 287         xregcomp(sed_cmd->sub_match, match, cflags);
 288         free(match);
 289
 290         return idx;
 291 }
 292
 293 static int parse_edit_cmd(sed_cmd_t *sed_cmd, const char *editstr)
 294 {
 295         int i, j;
 296
 297         /*
 298          * the string that gets passed to this function should look like this:
 299          *
 300          *    need one of these
 301          *    |
 302          *    |    this backslash (immediately following the edit command) is mandatory
 303          *    |    |
 304          *    [aic]\
 305          *    TEXT1\
 306          *    TEXT2\
 307          *    TEXTN
 308          *
 309          * as soon as we hit a TEXT line that has no trailing '\', we're done.
 310          * this means a command like:
 311          *
 312          * i\
 313          * INSERTME
 314          *
 315          * is a-ok.
 316          *
 317          */
 318         if ((*editstr != '\\') || ((editstr[1] != '\n') && (editstr[1] != '\r'))) {
 319                 error_msg_and_die("bad format in edit expression");
 320         }
 321
 322         /* store the edit line text */
 323         sed_cmd->editline = xmalloc(strlen(&editstr[2]) + 2);
 324         for (i = 2, j = 0; editstr[i] != '\0' && strchr("\r\n", editstr[i]) == NULL;
 325                         i++, j++) {
 326                 if ((editstr[i] == '\\') && strchr("\n\r", editstr[i+1]) != NULL) {
 327                         sed_cmd->editline[j] = '\n';
 328                         i++;
 329                 } else
 330                         sed_cmd->editline[j] = editstr[i];
 331         }
 332
 333         /* figure out if we need to add a newline */
 334         if (sed_cmd->editline[j-1] != '\n')
 335                 sed_cmd->editline[j++] = '\n';
 336
 337         /* terminate string */
 338         sed_cmd->editline[j] = '\0';
 339
 340         return i;
 341 }
 342
 343
 344 static int parse_file_cmd(sed_cmd_t *sed_cmd, const char *filecmdstr)
 345 {
 346         int idx = 0;
 347         int filenamelen = 0;
 348
 349         /*
 350          * the string that gets passed to this function should look like this:
 351          *    '[ ]filename'
 352          *      |  |
 353          *      |  a filename
 354          *      |
 355          *     optional whitespace
 356
 357          *   re: the file to be read, the GNU manual says the following: "Note that
 358          *   if filename cannot be read, it is treated as if it were an empty file,
 359          *   without any error indication." Thus, all of the following commands are
 360          *   perfectly leagal:
 361          *
 362          *   sed -e '1r noexist'
 363          *   sed -e '1r ;'
 364          *   sed -e '1r'
 365          */
 366
 367         /* the file command may be followed by whitespace; move past it. */
 368         while (isspace(filecmdstr[++idx]))
 369                 { ; }
 370
 371         /* the first non-whitespace we get is a filename. the filename ends when we
 372          * hit a normal sed command terminator or end of string */
 373         filenamelen = strcspn(&filecmdstr[idx], semicolon_whitespace);
 374         sed_cmd->filename = xmalloc(filenamelen + 1);
 375         safe_strncpy(sed_cmd->filename, &filecmdstr[idx], filenamelen + 1);
 376
 377         return idx + filenamelen;
 378 }
 379
 380 /*
 381  *  Process the commands arguments
 382  */
 383 static char *parse_cmd_str(sed_cmd_t * const sed_cmd, char *cmdstr)
 384 {
 385         /* handle (s)ubstitution command */
 386         if (sed_cmd->cmd == 's') {
 387                 cmdstr += parse_subst_cmd(sed_cmd, cmdstr);
 388         }
 389         /* handle edit cmds: (a)ppend, (i)nsert, and (c)hange */
 390         else if (strchr("aic", sed_cmd->cmd)) {
 391                 if ((sed_cmd->end_line || sed_cmd->end_match) && sed_cmd->cmd != 'c')
 392                         error_msg_and_die("only a beginning address can be specified for edit commands");
 393                 cmdstr += parse_edit_cmd(sed_cmd, cmdstr);
 394         }
 395         /* handle file cmds: (r)ead */
 396         else if (sed_cmd->cmd == 'r') {
 397                 if (sed_cmd->end_line || sed_cmd->end_match)
 398                         error_msg_and_die("Command only uses one address");
 399                 cmdstr += parse_file_cmd(sed_cmd, cmdstr);
 400         }
 401         /* if it wasnt a single-letter command that takes no arguments
 402          * then it must be an invalid command.
 403          */
 404         else if (strchr("nNpPqd=", sed_cmd->cmd) == 0) {
 405                 error_msg_and_die("Unsupported command %c", sed_cmd->cmd);
 406         }
 407
 408         /* give back whatever's left over */
 409         return(cmdstr);
 410 }
 411
 412 static char *add_cmd(sed_cmd_t *sed_cmd, char *cmdstr)
 413 {
 414
 415         /* Skip over leading whitespace and semicolons */
 416         cmdstr += strspn(cmdstr, semicolon_whitespace);
 417
 418         /* if we ate the whole thing, that means there was just trailing
 419          * whitespace or a final / no-op semicolon. either way, get out */
 420         if (*cmdstr == '\0') {
 421                 return(NULL);
 422         }
 423
 424         /* if this is a comment, jump past it and keep going */
 425         if (*cmdstr == '#') {
 426                 return(strpbrk(cmdstr, "\n\r"));
 427         }
 428
 429         /* parse the command
 430          * format is: [addr][,addr]cmd
 431          *            |----||-----||-|
 432          *            part1 part2  part3
 433          */
 434
 435         /* first part (if present) is an address: either a '$', a number or a /regex/ */
 436         cmdstr += get_address(&(sed_cmd->delimiter), cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
 437
 438         /* second part (if present) will begin with a comma */
 439         if (*cmdstr == ',') {
 440                 int idx;
 441                 cmdstr++;
 442                 idx = get_address(&(sed_cmd->delimiter), cmdstr, &sed_cmd->end_line, &sed_cmd->end_match);
 443                 if (idx == 0) {
 444                         error_msg_and_die("get_address: no address found in string\n"
 445                                 "\t(you probably didn't check the string you passed me)");
 446                 }
 447                 cmdstr += idx;
 448         }
 449
 450         /* skip whitespace before the command */
 451         while (isspace(*cmdstr)) {
 452                 cmdstr++;
 453         }
 454
 455         /* there my be the inversion flag between part2 and part3 */
 456         if (*cmdstr == '!') {
 457                 sed_cmd->invert = 1;
 458                 cmdstr++;
 459
 460 #ifdef SED_FEATURE_STRICT_CHECKING
 461                 /* According to the spec
 462                  * It is unspecified whether <blank>s can follow a '!' character,
 463                  * and conforming applications shall not follow a '!' character
 464                  * with <blank>s.
 465                  */
 466                 if (isblank(cmdstr[idx]) {
 467                         error_msg_and_die("blank follows '!'");
 468                 }
 469 #else
 470                 /* skip whitespace before the command */
 471                 while (isspace(*cmdstr)) {
 472                         cmdstr++;
 473                 }
 474 #endif
 475
 476         }
 477
 478         /* last part (mandatory) will be a command */
 479         if (*cmdstr == '\0')
 480                 error_msg_and_die("missing command");
 481
 482         sed_cmd->cmd = *cmdstr;
 483         cmdstr++;
 484
 485         if (sed_cmd->cmd == '{') {
 486                 do {
 487                         char *end_ptr = strpbrk(cmdstr, ";}");
 488                         *end_ptr = '\0';
 489                         add_cmd(sed_cmd, cmdstr);
 490                         cmdstr = end_ptr + 1;
 491                 } while (*cmdstr != '\0');
 492         } else {
 493
 494                 cmdstr = parse_cmd_str(sed_cmd, cmdstr);
 495
 496                 /* Add the command to the command array */
 497                 sed_cmds = xrealloc(sed_cmds, sizeof(sed_cmd_t) * (++ncmds));
 498                 sed_cmds[ncmds-1] = xmalloc(sizeof(sed_cmd_t));
 499                 memcpy(sed_cmds[ncmds-1], sed_cmd, sizeof(sed_cmd_t));
 500         }
 501         return(cmdstr);
 502 }
 503
 504 static void add_cmd_str(char *cmdstr)
 505 {
 506         do {
 507                 sed_cmd_t *sed_cmd;
 508                 sed_cmd = xcalloc(1, sizeof(sed_cmd_t));
 509                 cmdstr = add_cmd(sed_cmd, cmdstr);
 510         } while (cmdstr && strlen(cmdstr));
 511 }
 512
 513
 514 static void load_cmd_file(char *filename)
 515 {
 516         FILE *cmdfile;
 517         char *line;
 518         char *nextline;
 519
 520         cmdfile = xfopen(filename, "r");
 521
 522         while ((line = get_line_from_file(cmdfile)) != NULL) {
 523                 /* if a line ends with '\' it needs the next line appended to it */
 524                 while (line[strlen(line)-2] == '\\' &&
 525                                 (nextline = get_line_from_file(cmdfile)) != NULL) {
 526                         line = xrealloc(line, strlen(line) + strlen(nextline) + 1);
 527                         strcat(line, nextline);
 528                         free(nextline);
 529                 }
 530                 /* eat trailing newline (if any) --if I don't do this, edit commands
 531                  * (aic) will print an extra newline */
 532                 chomp(line);
 533                 add_cmd_str(line);
 534                 free(line);
 535         }
 536 }
 537
 538 struct pipeline {
 539         char *buf;
 540         int idx;
 541         int len;
 542 };
 543
 544 #define PIPE_MAGIC 0x7f
 545 #define PIPE_GROW 64
 546
 547 void pipe_putc(struct pipeline *const pipeline, char c)
 548 {
 549         if (pipeline->buf[pipeline->idx] == PIPE_MAGIC) {
 550                 pipeline->buf =
 551                         xrealloc(pipeline->buf, pipeline->len + PIPE_GROW);
 552                 memset(pipeline->buf + pipeline->len, 0, PIPE_GROW);
 553                 pipeline->len += PIPE_GROW;
 554                 pipeline->buf[pipeline->len - 1] = PIPE_MAGIC;
 555         }
 556         pipeline->buf[pipeline->idx++] = (c);
 557 }
 558
 559 #define pipeputc(c)     pipe_putc(pipeline, c)
 560
 561 #if 0
 562 { if (pipeline[pipeline_idx] == PIPE_MAGIC) { \
 563         pipeline = xrealloc(pipeline, pipeline_len+PIPE_GROW); \
 564         memset(pipeline+pipeline_len, 0, PIPE_GROW); \
 565         pipeline_len += PIPE_GROW; \
 566         pipeline[pipeline_len-1] = PIPE_MAGIC; } \
 567         pipeline[pipeline_idx++] = (c); }
 568 #endif
 569
 570 static void print_subst_w_backrefs(const char *line, const char *replace,
 571         regmatch_t *regmatch, struct pipeline *const pipeline, int matches)
 572 {
 573         int i;
 574
 575         /* go through the replacement string */
 576         for (i = 0; replace[i]; i++) {
 577                 /* if we find a backreference (\1, \2, etc.) print the backref'ed * text */
 578                 if (replace[i] == '\\' && isdigit(replace[i+1])) {
 579                         int j;
 580                         char tmpstr[2];
 581                         int backref;
 582                         ++i; /* i now indexes the backref number, instead of the leading slash */
 583                         tmpstr[0] = replace[i];
 584                         tmpstr[1] = 0;
 585                         backref = atoi(tmpstr);
 586                         /* print out the text held in regmatch[backref] */
 587                         if (backref <= matches && regmatch[backref].rm_so != -1)
 588                                 for (j = regmatch[backref].rm_so; j < regmatch[backref].rm_eo; j++)
 589                                         pipeputc(line[j]);
 590                 }
 591
 592                 /* if we find a backslash escaped character, print the character */
 593                 else if (replace[i] == '\\') {
 594                         ++i;
 595                         pipeputc(replace[i]);
 596                 }
 597
 598                 /* if we find an unescaped '&' print out the whole matched text.
 599                  * fortunately, regmatch[0] contains the indicies to the whole matched
 600                  * expression (kinda seems like it was designed for just such a
 601                  * purpose...) */
 602                 else if (replace[i] == '&' && replace[i-1] != '\\') {
 603                         int j;
 604                         for (j = regmatch[0].rm_so; j < regmatch[0].rm_eo; j++)
 605                                 pipeputc(line[j]);
 606                 }
 607                 /* nothing special, just print this char of the replacement string to stdout */
 608                 else
 609                         pipeputc(replace[i]);
 610         }
 611 }
 612
 613 static int do_subst_command(const sed_cmd_t *sed_cmd, char **line)
 614 {
 615         char *hackline = *line;
 616         struct pipeline thepipe = { NULL, 0 , 0};
 617         struct pipeline *const pipeline = &thepipe;
 618         int altered = 0;
 619         regmatch_t *regmatch = NULL;
 620
 621         /* we only proceed if the substitution 'search' expression matches */
 622         if (regexec(sed_cmd->sub_match, hackline, 0, NULL, 0) == REG_NOMATCH)
 623                 return 0;
 624
 625         /* whaddaya know, it matched. get the number of back references */
 626         regmatch = xmalloc(sizeof(regmatch_t) * (sed_cmd->num_backrefs+1));
 627
 628         /* allocate more PIPE_GROW bytes
 629            if replaced string is larger than original */
 630         thepipe.len = strlen(hackline)+PIPE_GROW;
 631         thepipe.buf = xcalloc(1, thepipe.len);
 632         /* buffer magic */
 633         thepipe.buf[thepipe.len-1] = PIPE_MAGIC;
 634
 635         /* and now, as long as we've got a line to try matching and if we can match
 636          * the search string, we make substitutions */
 637         while ((*hackline || !altered) && (regexec(sed_cmd->sub_match, hackline,
 638                                         sed_cmd->num_backrefs+1, regmatch, 0) != REG_NOMATCH) ) {
 639                 int i;
 640
 641                 /* print everything before the match */
 642                 for (i = 0; i < regmatch[0].rm_so; i++)
 643                         pipeputc(hackline[i]);
 644
 645                 /* then print the substitution string */
 646                 print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch,
 647                                 pipeline, sed_cmd->num_backrefs);
 648
 649                 /* advance past the match */
 650                 hackline += regmatch[0].rm_eo;
 651                 /* flag that something has changed */
 652                 altered++;
 653
 654                 /* if we're not doing this globally, get out now */
 655                 if (!sed_cmd->sub_g)
 656                         break;
 657         }
 658
 659         for (; *hackline; hackline++) pipeputc(*hackline);
 660         if (thepipe.buf[thepipe.idx] == PIPE_MAGIC) thepipe.buf[thepipe.idx] = 0;
 661
 662         /* cleanup */
 663         free(regmatch);
 664
 665         free(*line);
 666         *line = thepipe.buf;
 667         return altered;
 668 }
 669
 670
 671 static void process_file(FILE *file)
 672 {
 673         char *line;
 674         static int linenum = 0; /* GNU sed does not restart counting lines at EOF */
 675         unsigned int still_in_range = 0;
 676         int altered;
 677         int i;
 678
 679         line = get_line_from_file(file);
 680         if (line == NULL) {
 681                 return;
 682         }
 683         chomp(line);
 684
 685         /* go through every line in the file */
 686         do {
 687                 char *next_line;
 688
 689                 /* Read one line in advance so we can act on the last line, the '$' address */
 690                 next_line = get_line_from_file(file);
 691
 692                 chomp(next_line);
 693                 linenum++;
 694                 altered = 0;
 695
 696                 /* for every line, go through all the commands */
 697                 for (i = 0; i < ncmds; i++) {
 698                         sed_cmd_t *sed_cmd = sed_cmds[i];
 699                         int deleted = 0;
 700
 701                         /*
 702                          * entry point into sedding...
 703                          */
 704                         int matched = (
 705                                         /* no range necessary */
 706                                         (sed_cmd->beg_line == 0 && sed_cmd->end_line == 0 &&
 707                                          sed_cmd->beg_match == NULL &&
 708                                          sed_cmd->end_match == NULL) ||
 709                                         /* this line number is the first address we're looking for */
 710                                         (sed_cmd->beg_line && (sed_cmd->beg_line == linenum)) ||
 711                                         /* this line matches our first address regex */
 712                                         (sed_cmd->beg_match && (regexec(sed_cmd->beg_match, line, 0, NULL, 0) == 0)) ||
 713                                         /* we are currently within the beginning & ending address range */
 714                                         still_in_range || ((sed_cmd->beg_line == -1) && (next_line == NULL))
 715                            );
 716
 717                         if (sed_cmd->invert ^ matched) {
 718
 719                                 /*
 720                                  * actual sedding
 721                                  */
 722                                 switch (sed_cmd->cmd) {
 723                                         case '=':
 724                                                 printf("%d\n", linenum);
 725                                                 break;
 726                                         case 'P': {     /* Write the current pattern space upto the first newline */
 727                                                         char *tmp = strchr(line, '\n');
 728                                                         if (tmp) {
 729                                                                 *tmp = '\0';
 730                                                         }
 731                                                 }
 732                                         case 'p':       /* Write the current pattern space to output */
 733                                                 puts(line);
 734                                                 break;
 735                                         case 'd':
 736                                                 altered++;
 737                                                 deleted = 1;
 738                                                 break;
 739
 740                                         case 's':
 741
 742                                                 /*
 743                                                  * Some special cases for 's' printing to make it compliant with
 744                                                  * GNU sed printing behavior (aka "The -n | s///p Matrix"):
 745                                                  *
 746                                                  *    -n ONLY = never print anything regardless of any successful
 747                                                  *    substitution
 748                                                  *
 749                                                  *    s///p ONLY = always print successful substitutions, even if
 750                                                  *    the line is going to be printed anyway (line will be printed
 751                                                  *    twice).
 752                                                  *
 753                                                  *    -n AND s///p = print ONLY a successful substitution ONE TIME;
 754                                                  *    no other lines are printed - this is the reason why the 'p'
 755                                                  *    flag exists in the first place.
 756                                                  */
 757
 758                                                 /* if the user specified that they didn't want anything printed (i.e., a -n
 759                                                  * flag and no 'p' flag after the s///), then there's really no point doing
 760                                                  * anything here. */
 761                                                 if (be_quiet && !sed_cmd->sub_p)
 762                                                         break;
 763
 764                                                 /* we print the line once, unless we were told to be quiet */
 765                                                 if (!be_quiet)
 766                                                         altered |= do_subst_command(sed_cmd, &line);
 767
 768                                                 /* we also print the line if we were given the 'p' flag
 769                                                  * (this is quite possibly the second printing) */
 770                                                 if (sed_cmd->sub_p)
 771                                                         altered |= do_subst_command(sed_cmd, &line);
 772                                                 if (altered && (i+1 >= ncmds || sed_cmds[i+1]->cmd != 's'))
 773                                                         puts(line);
 774
 775                                                 break;
 776
 777                                         case 'a':
 778                                                 puts(line);
 779                                                 fputs(sed_cmd->editline, stdout);
 780                                                 altered++;
 781                                                 break;
 782
 783                                         case 'i':
 784                                                 fputs(sed_cmd->editline, stdout);
 785                                                 break;
 786
 787                                         case 'c':
 788                                                 /* single-address case */
 789                                                 if ((sed_cmd->end_match == NULL && sed_cmd->end_line == 0)
 790                                                 /* multi-address case */
 791                                                 /* - matching text */
 792                                                 || (sed_cmd->end_match && (regexec(sed_cmd->end_match, line, 0, NULL, 0) == 0))
 793                                                 /* - matching line numbers */
 794                                                 || (sed_cmd->end_line > 0 && sed_cmd->end_line == linenum))
 795                                                 {
 796                                                         fputs(sed_cmd->editline, stdout);
 797                                                 }
 798                                                 altered++;
 799
 800                                                 break;
 801
 802                                         case 'r': {
 803                                                         FILE *outfile;
 804                                                         puts(line);
 805                                                         outfile = fopen(sed_cmd->filename, "r");
 806                                                         if (outfile)
 807                                                                 print_file(outfile);
 808                                                                 /* else if we couldn't open the output file,
 809                                                                  * no biggie, just don't print anything */
 810                                                                 altered++;
 811                                                 }
 812                                                 break;
 813                                         case 'q':       /* Branch to end of script and quit */
 814                                                 free(line);
 815                                                 return;
 816                                         case 'n':       /* Read next line from input */
 817                                                 free(line);
 818                                                 line = next_line;
 819                                                 next_line = get_line_from_file(file);
 820                                                 chomp(next_line);
 821                                                 linenum++;
 822                                                 break;
 823                                         case 'N':       /* Append the next line to the current line */
 824                                                 line = realloc(line, strlen(line) + strlen(next_line) + 2);
 825                                                 strcat(line, "\n");
 826                                                 strcat(line, next_line);
 827                                                 next_line = get_line_from_file(file);
 828                                                 chomp(next_line);
 829                                                 linenum++;
 830                                 }
 831                         }
 832
 833                         /*
 834                          * exit point from sedding...
 835                          */
 836                         if (matched) {
 837                                 if (
 838                                         /* this is a single-address command or... */
 839                                         (sed_cmd->end_line == 0 && sed_cmd->end_match == NULL) || (
 840                                                 /* we were in the middle of our address range (this
 841                                                  * isn't the first time through) and.. */
 842                                                 (still_in_range == 1) && (
 843                                                         /* this line number is the last address we're looking for or... */
 844                                                         (sed_cmd->end_line && (sed_cmd->end_line == linenum)) ||
 845                                                         /* this line matches our last address regex */
 846                                                         (sed_cmd->end_match && (regexec(sed_cmd->end_match, line, 0, NULL, 0) == 0))
 847                                                 )
 848                                         )
 849                                 ) {
 850                                         /* we're out of our address range */
 851                                         still_in_range = 0;
 852                                 }
 853
 854                                 /* didn't hit the exit? then we're still in the middle of an address range */
 855                                 else {
 856                                         still_in_range = 1;
 857                                 }
 858                         }
 859
 860                         if (deleted)
 861                                 break;
 862                 }
 863
 864                 /* we will print the line unless we were told to be quiet or if the
 865                  * line was altered (via a 'd'elete or 's'ubstitution), in which case
 866                  * the altered line was already printed */
 867                 if (!be_quiet && !altered)
 868                         puts(line);
 869
 870                 free(line);
 871                 line = next_line;
 872         } while (line);
 873 }
 874
 875 extern int sed_main(int argc, char **argv)
 876 {
 877         int opt, status = EXIT_SUCCESS;
 878
 879 #ifdef CONFIG_FEATURE_CLEAN_UP
 880         /* destroy command strings on exit */
 881         if (atexit(destroy_cmd_strs) == -1)
 882                 perror_msg_and_die("atexit");
 883 #endif
 884
 885         /* do normal option parsing */
 886         while ((opt = getopt(argc, argv, "ne:f:")) > 0) {
 887                 switch (opt) {
 888                         case 'n':
 889                                 be_quiet++;
 890                                 break;
 891                         case 'e':
 892                                 add_cmd_str(optarg);
 893                                 break;
 894                         case 'f':
 895                                 load_cmd_file(optarg);
 896                                 break;
 897                         default:
 898                                 show_usage();
 899                 }
 900         }
 901
 902         /* if we didn't get a pattern from a -e and no command file was specified,
 903          * argv[optind] should be the pattern. no pattern, no worky */
 904         if (ncmds == 0) {
 905                 if (argv[optind] == NULL)
 906                         show_usage();
 907                 else {
 908                         add_cmd_str(argv[optind]);
 909                         optind++;
 910                 }
 911         }
 912
 913         /* argv[(optind)..(argc-1)] should be names of file to process. If no
 914          * files were specified or '-' was specified, take input from stdin.
 915          * Otherwise, we process all the files specified. */
 916         if (argv[optind] == NULL || (strcmp(argv[optind], "-") == 0)) {
 917                 process_file(stdin);
 918         }
 919         else {
 920                 int i;
 921                 FILE *file;
 922                 for (i = optind; i < argc; i++) {
 923                         file = wfopen(argv[i], "r");
 924                         if (file) {
 925                                 process_file(file);
 926                                 fclose(file);
 927                         } else
 928                                 status = EXIT_FAILURE;
 929                 }
 930         }
 931
 932         return status;
 933 }