editors/sed.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * sed.c - very minimalist version of sed
   4  *
   5  * Copyright (C) 1999,2000,2001 by Lineo, inc. and Mark Whitley
   6  * Copyright (C) 1999,2000,2001 by Mark Whitley <markw@codepoet.org>
   7  * Copyright (C) 2002  Matt Kraai
   8  * Copyright (C) 2003 by Glenn McGrath <bug1@optushome.com.au>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  *
  24  */
  25
  26 /* Code overview.
  27
  28   Files are laid out to avoid unnecessary function declarations.  So for
  29   example, every function add_cmd calls occurs before add_cmd in this file.
  30
  31   add_cmd() is called on each line of sed command text (from a file or from
  32   the command line).  It calls get_address() and parse_cmd_args().  The
  33   resulting sed_cmd_t structures are appended to a linked list
  34   (sed_cmd_head/sed_cmd_tail).
  35
  36   process_file() does actual sedding, reading data lines from an input FILE *
  37   (which could be stdin) and applying the sed command list (sed_cmd_head) to
  38   each of the resulting lines.
  39
  40   sed_main() is where external code calls into this, with a command line.
  41 */
  42
  43
  44 /*
  45         Supported features and commands in this version of sed:
  46
  47          - comments ('#')
  48          - address matching: num|/matchstr/[,num|/matchstr/|$]command
  49          - commands: (p)rint, (d)elete, (s)ubstitue (with g & I flags)
  50          - edit commands: (a)ppend, (i)nsert, (c)hange
  51          - file commands: (r)ead
  52          - backreferences in substitution expressions (\1, \2...\9)
  53          - grouped commands: {cmd1;cmd2}
  54          - transliteration (y/source-chars/dest-chars/)
  55          - pattern space hold space storing / swapping (g, h, x)
  56          - labels / branching (: label, b, t)
  57
  58          (Note: Specifying an address (range) to match is *optional*; commands
  59          default to the whole pattern space if no specific address match was
  60          requested.)
  61
  62         Unsupported features:
  63
  64          - GNU extensions
  65          - and more.
  66
  67         Todo:
  68
  69          - Create a wrapper around regex to make libc's regex conform with sed
  70          - Fix bugs
  71
  72
  73         Reference http://www.opengroup.org/onlinepubs/007904975/utilities/sed.html
  74 */
  75
  76 #include <stdio.h>
  77 #include <unistd.h>             /* for getopt() */
  78 #include <regex.h>
  79 #include <string.h>             /* for strdup() */
  80 #include <errno.h>
  81 #include <ctype.h>              /* for isspace() */
  82 #include <stdlib.h>
  83 #include "busybox.h"
  84
  85 typedef struct sed_cmd_s {
  86     /* Ordered by alignment requirements: currently 36 bytes on x86 */
  87
  88     /* address storage */
  89     regex_t *beg_match; /* sed -e '/match/cmd' */
  90     regex_t *end_match; /* sed -e '/match/,/end_match/cmd' */
  91     regex_t *sub_match; /* For 's/sub_match/string/' */
  92     int beg_line;               /* 'sed 1p'   0 == apply commands to all lines */
  93     int end_line;               /* 'sed 1,3p' 0 == one line only. -1 = last line ($) */
  94
  95     FILE *file;                 /* File (sr) command writes to, -1 for none. */
  96     char *string;               /* Data string for (saicytb) commands. */
  97
  98     unsigned short which_match;         /* (s) Which match to replace (0 for all) */
  99
 100     /* Bitfields (gcc won't group them if we don't) */
 101     unsigned int invert:1;                      /* the '!' after the address */
 102     unsigned int in_match:1;            /* Next line also included in match? */
 103     unsigned int no_newline:1;          /* Last line written by (sr) had no '\n' */
 104     unsigned int sub_p:1;                       /* (s) print option */
 105
 106
 107     /* GENERAL FIELDS */
 108     char cmd;                           /* The command char: abcdDgGhHilnNpPqrstwxy:={} */
 109     struct sed_cmd_s *next;     /* Next command (linked list, NULL terminated) */
 110 } sed_cmd_t;
 111
 112 /* globals */
 113 /* options */
 114 static int be_quiet = 0;
 115
 116 static const char bad_format_in_subst[] =
 117         "bad format in substitution expression";
 118 const char *const semicolon_whitespace = "; \n\r\t\v";
 119
 120 regmatch_t regmatch[10];
 121 static regex_t *previous_regex_ptr = NULL;
 122
 123 /* linked list of sed commands */
 124 static sed_cmd_t sed_cmd_head;
 125 static sed_cmd_t *sed_cmd_tail = &sed_cmd_head;
 126
 127 /* Linked list of append lines */
 128 struct append_list {
 129         char *string;
 130         struct append_list *next;
 131 };
 132 struct append_list *append_head=NULL, *append_tail=NULL;
 133
 134 #ifdef CONFIG_FEATURE_CLEAN_UP
 135 static void free_and_close_stuff(void)
 136 {
 137         sed_cmd_t *sed_cmd = sed_cmd_head.next;
 138
 139         while(append_head) {
 140                 append_tail=append_head->next;
 141                 free(append_head->string);
 142                 free(append_head);
 143                 append_head=append_tail;
 144         }
 145
 146         while (sed_cmd) {
 147                 sed_cmd_t *sed_cmd_next = sed_cmd->next;
 148
 149                 if(sed_cmd->file)
 150                         bb_xprint_and_close_file(sed_cmd->file);
 151
 152                 if (sed_cmd->beg_match) {
 153                         regfree(sed_cmd->beg_match);
 154                         free(sed_cmd->beg_match);
 155                 }
 156                 if (sed_cmd->end_match) {
 157                         regfree(sed_cmd->end_match);
 158                         free(sed_cmd->end_match);
 159                 }
 160                 if (sed_cmd->sub_match) {
 161                         regfree(sed_cmd->sub_match);
 162                         free(sed_cmd->sub_match);
 163                 }
 164                 free(sed_cmd->string);
 165                 free(sed_cmd);
 166                 sed_cmd = sed_cmd_next;
 167         }
 168 }
 169 #endif
 170
 171 /* strdup, replacing "\n" with '\n', and "\delimiter" with 'delimiter' */
 172
 173 static void parse_escapes(char *dest, const char *string, int len, char from, char to)
 174 {
 175         int i=0;
 176
 177         while(i<len) {
 178                 if(string[i] == '\\') {
 179                         if(!to || string[i+1] == from) {
 180                                 *(dest++) = to ? to : string[i+1];
 181                                 i+=2;
 182                                 continue;
 183                         } else *(dest++)=string[i++];
 184                 }
 185                 *(dest++) = string[i++];
 186         }
 187         *dest=0;
 188 }
 189
 190 static char *copy_parsing_slashn(const char *string, int len)
 191 {
 192         char *dest=xmalloc(len+1);
 193
 194         parse_escapes(dest,string,len,'n','\n');
 195         return dest;
 196 }
 197
 198
 199 /*
 200  * index_of_next_unescaped_regexp_delim - walks left to right through a string
 201  * beginning at a specified index and returns the index of the next regular
 202  * expression delimiter (typically a forward * slash ('/')) not preceeded by
 203  * a backslash ('\').
 204  */
 205 static int index_of_next_unescaped_regexp_delim(const char delimiter,
 206         const char *str)
 207 {
 208         int bracket = -1;
 209         int escaped = 0;
 210         int idx = 0;
 211         char ch;
 212
 213         for (; (ch = str[idx]); idx++) {
 214                 if (bracket != -1) {
 215                         if (ch == ']' && !(bracket == idx - 1 || (bracket == idx - 2
 216                                         && str[idx - 1] == '^')))
 217                                 bracket = -1;
 218                 } else if (escaped)
 219                         escaped = 0;
 220                 else if (ch == '\\')
 221                         escaped = 1;
 222                 else if (ch == '[')
 223                         bracket = idx;
 224                 else if (ch == delimiter)
 225                         return idx;
 226         }
 227
 228         /* if we make it to here, we've hit the end of the string */
 229         return -1;
 230 }
 231
 232 /*
 233  *  Returns the index of the third delimiter
 234  */
 235 static int parse_regex_delim(const char *cmdstr, char **match, char **replace)
 236 {
 237         const char *cmdstr_ptr = cmdstr;
 238         char delimiter;
 239         int idx = 0;
 240
 241         /* verify that the 's' or 'y' is followed by something.  That something
 242          * (typically a 'slash') is now our regexp delimiter... */
 243         if (*cmdstr == '\0') bb_error_msg_and_die(bad_format_in_subst);
 244         delimiter = *(cmdstr_ptr++);
 245
 246         /* save the match string */
 247         idx = index_of_next_unescaped_regexp_delim(delimiter, cmdstr_ptr);
 248         if (idx == -1) {
 249                 bb_error_msg_and_die(bad_format_in_subst);
 250         }
 251         *match = copy_parsing_slashn(cmdstr_ptr, idx);
 252
 253         /* save the replacement string */
 254         cmdstr_ptr += idx + 1;
 255         idx = index_of_next_unescaped_regexp_delim(delimiter, cmdstr_ptr);
 256         if (idx == -1) {
 257                 bb_error_msg_and_die(bad_format_in_subst);
 258         }
 259         *replace = copy_parsing_slashn(cmdstr_ptr, idx);
 260
 261         return ((cmdstr_ptr - cmdstr) + idx);
 262 }
 263
 264 /*
 265  * returns the index in the string just past where the address ends.
 266  */
 267 static int get_address(char *my_str, int *linenum, regex_t ** regex)
 268 {
 269         char *pos = my_str;
 270
 271         if (isdigit(*my_str)) {
 272                 *linenum = strtol(my_str, &pos, 10);
 273                 /* endstr shouldnt ever equal NULL */
 274         } else if (*my_str == '$') {
 275                 *linenum = -1;
 276                 pos++;
 277         } else if (*my_str == '/' || *my_str == '\\') {
 278                 int next;
 279                 char delimiter;
 280                 char *temp;
 281
 282                 if (*my_str == '\\') delimiter = *(++pos);
 283                 else delimiter = '/';
 284                 next = index_of_next_unescaped_regexp_delim(delimiter, ++pos);
 285                 if (next == -1)
 286                         bb_error_msg_and_die("unterminated match expression");
 287
 288                 temp=copy_parsing_slashn(pos,next);
 289                 *regex = (regex_t *) xmalloc(sizeof(regex_t));
 290                 xregcomp(*regex, temp, REG_NEWLINE);
 291                 free(temp);
 292                 /* Move position to next character after last delimiter */
 293                 pos+=(next+1);
 294         }
 295         return pos - my_str;
 296 }
 297
 298 /* Grab a filename.  Whitespace at start is skipped, then goes to EOL. */
 299 static int parse_file_cmd(sed_cmd_t * sed_cmd, const char *filecmdstr, char **retval)
 300 {
 301         int start = 0, idx, hack=0;
 302
 303         /* Skip whitespace, then grab filename to end of line */
 304         while (isspace(filecmdstr[start])) start++;
 305         idx=start;
 306         while(filecmdstr[idx] && filecmdstr[idx]!='\n') idx++;
 307         /* If lines glued together, put backslash back. */
 308         if(filecmdstr[idx]=='\n') hack=1;
 309         if(idx==start) bb_error_msg_and_die("Empty filename");
 310         *retval = bb_xstrndup(filecmdstr+start, idx-start+hack+1);
 311         if(hack) *(idx+*retval)='\\';
 312
 313         return idx;
 314 }
 315
 316 static int parse_subst_cmd(sed_cmd_t * const sed_cmd, char *substr)
 317 {
 318         int cflags = 0;
 319         char *match;
 320         int idx = 0;
 321
 322         /*
 323          * A substitution command should look something like this:
 324          *    s/match/replace/ #gIpw
 325          *    ||     |        |||
 326          *    mandatory       optional
 327          */
 328         idx = parse_regex_delim(substr, &match, &sed_cmd->string);
 329
 330         /* determine the number of back references in the match string */
 331         /* Note: we compute this here rather than in the do_subst_command()
 332          * function to save processor time, at the expense of a little more memory
 333          * (4 bits) per sed_cmd */
 334
 335         /* process the flags */
 336
 337         sed_cmd->which_match=1;
 338         while (substr[++idx]) {
 339                 /* Parse match number */
 340                 if(isdigit(substr[idx])) {
 341                         if(match[0]!='^') {
 342                                 /* Match 0 treated as all, multiple matches we take the last one. */
 343                                 char *pos=substr+idx;
 344                                 sed_cmd->which_match=(unsigned short)strtol(substr+idx,&pos,10);
 345                                 idx=pos-substr;
 346                         }
 347                         /* Skip spaces */
 348                         if(isspace(substr[idx])) continue;
 349                         continue;
 350                 }
 351                 switch (substr[idx]) {
 352                         /* Replace all occurrences */
 353                         case 'g':
 354                                 if (match[0] != '^') sed_cmd->which_match = 0;
 355                                 break;
 356                         /* Print pattern space */
 357                         case 'p':
 358                                 sed_cmd->sub_p = 1;
 359                                 break;
 360                         case 'w':
 361                         {
 362                                 char *temp;
 363                                 idx+=parse_file_cmd(sed_cmd,substr+idx,&temp);
 364
 365                                 break;
 366                         }
 367                         /* Ignore case (gnu exension) */
 368                         case 'I':
 369                                 cflags |= REG_ICASE;
 370                                 break;
 371                         case ';':
 372                         case '}':
 373                                 goto out;
 374                         default:
 375                                 bb_error_msg_and_die("bad option in substitution expression");
 376                 }
 377         }
 378 out:
 379         /* compile the match string into a regex */
 380         if (*match != '\0') {
 381                 /* If match is empty, we use last regex used at runtime */
 382                 sed_cmd->sub_match = (regex_t *) xmalloc(sizeof(regex_t));
 383                 xregcomp(sed_cmd->sub_match, match, cflags);
 384         }
 385         free(match);
 386
 387         return idx;
 388 }
 389
 390 /*
 391  *  Process the commands arguments
 392  */
 393 static char *parse_cmd_args(sed_cmd_t *sed_cmd, char *cmdstr)
 394 {
 395         /* handle (s)ubstitution command */
 396         if (sed_cmd->cmd == 's') cmdstr += parse_subst_cmd(sed_cmd, cmdstr);
 397         /* handle edit cmds: (a)ppend, (i)nsert, and (c)hange */
 398         else if (strchr("aic", sed_cmd->cmd)) {
 399                 if ((sed_cmd->end_line || sed_cmd->end_match) && sed_cmd->cmd != 'c')
 400                         bb_error_msg_and_die
 401                                 ("only a beginning address can be specified for edit commands");
 402                 while(isspace(*cmdstr)) cmdstr++;
 403                 sed_cmd->string = bb_xstrdup(cmdstr);
 404                 parse_escapes(sed_cmd->string,sed_cmd->string,strlen(cmdstr),0,0);
 405                 cmdstr += strlen(cmdstr);
 406         /* handle file cmds: (r)ead */
 407         } else if(strchr("rw", sed_cmd->cmd)) {
 408                 if (sed_cmd->end_line || sed_cmd->end_match)
 409                         bb_error_msg_and_die("Command only uses one address");
 410                 cmdstr += parse_file_cmd(sed_cmd, cmdstr, &sed_cmd->string);
 411                 if(sed_cmd->cmd=='w')
 412                         sed_cmd->file=bb_xfopen(sed_cmd->string,"w");
 413         /* handle branch commands */
 414         } else if (strchr(":bt", sed_cmd->cmd)) {
 415                 int length;
 416
 417                 while(isspace(*cmdstr)) cmdstr++;
 418                 length = strcspn(cmdstr, semicolon_whitespace);
 419                 if (length) {
 420                         sed_cmd->string = strndup(cmdstr, length);
 421                         cmdstr += length;
 422                 }
 423         }
 424         /* translation command */
 425         else if (sed_cmd->cmd == 'y') {
 426                 char *match, *replace;
 427                 int i=cmdstr[0];
 428
 429                 cmdstr+=parse_regex_delim(cmdstr, &match, &replace)+1;
 430                 /* \n already parsed, but \delimiter needs unescaping. */
 431                 parse_escapes(match,match,strlen(match),i,i);
 432                 parse_escapes(replace,replace,strlen(replace),i,i);
 433
 434                 sed_cmd->string = xcalloc(1, (strlen(match) + 1) * 2);
 435                 for (i = 0; match[i] && replace[i]; i++) {
 436                         sed_cmd->string[i * 2] = match[i];
 437                         sed_cmd->string[(i * 2) + 1] = replace[i];
 438                 }
 439                 free(match);
 440                 free(replace);
 441         }
 442         /* if it wasnt a single-letter command that takes no arguments
 443          * then it must be an invalid command.
 444          */
 445         else if (strchr("dDgGhHlnNpPqx={}", sed_cmd->cmd) == 0) {
 446                 bb_error_msg_and_die("Unsupported command %c", sed_cmd->cmd);
 447         }
 448
 449         /* give back whatever's left over */
 450         return (cmdstr);
 451 }
 452
 453
 454 /* Parse address+command sets, skipping comment lines. */
 455
 456 void add_cmd(char *cmdstr)
 457 {
 458         static char *add_cmd_line=NULL;
 459         sed_cmd_t *sed_cmd;
 460         int temp;
 461
 462         /* Append this line to any unfinished line from last time. */
 463         if(add_cmd_line) {
 464                 int lastlen=strlen(add_cmd_line);
 465                 char *tmp=xmalloc(lastlen+strlen(cmdstr)+2);
 466
 467                 memcpy(tmp,add_cmd_line,lastlen);
 468                 tmp[lastlen]='\n';
 469                 strcpy(tmp+lastlen+1,cmdstr);
 470                 free(add_cmd_line);
 471                 cmdstr=add_cmd_line=tmp;
 472         } else add_cmd_line=NULL;
 473
 474         /* If this line ends with backslash, request next line. */
 475         temp=strlen(cmdstr);
 476         if(temp && cmdstr[temp-1]=='\\') {
 477                 if(!add_cmd_line) add_cmd_line=strdup(cmdstr);
 478                 add_cmd_line[temp-1]=0;
 479                 return;
 480         }
 481
 482         /* Loop parsing all commands in this line. */
 483         while(*cmdstr) {
 484                 /* Skip leading whitespace and semicolons */
 485                 cmdstr += strspn(cmdstr, semicolon_whitespace);
 486
 487                 /* If no more commands, exit. */
 488                 if(!*cmdstr) break;
 489
 490                 /* if this is a comment, jump past it and keep going */
 491                 if (*cmdstr == '#') {
 492                         /* "#n" is the same as using -n on the command line */
 493                         if (cmdstr[1] == 'n') be_quiet++;
 494                         if(!(cmdstr=strpbrk(cmdstr, "\n\r"))) break;
 495                         continue;
 496                 }
 497
 498                 /* parse the command
 499                  * format is: [addr][,addr][!]cmd
 500                  *            |----||-----||-|
 501                  *            part1 part2  part3
 502                  */
 503
 504                 sed_cmd = xcalloc(1, sizeof(sed_cmd_t));
 505
 506                 /* first part (if present) is an address: either a '$', a number or a /regex/ */
 507                 cmdstr += get_address(cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
 508
 509                 /* second part (if present) will begin with a comma */
 510                 if (*cmdstr == ',') {
 511                         int idx;
 512
 513                         cmdstr++;
 514                         idx = get_address(cmdstr, &sed_cmd->end_line, &sed_cmd->end_match);
 515                         if (!idx) bb_error_msg_and_die("get_address: no address found in string\n");
 516                         cmdstr += idx;
 517                 }
 518
 519                 /* skip whitespace before the command */
 520                 while (isspace(*cmdstr)) cmdstr++;
 521
 522                 /* Check for inversion flag */
 523                 if (*cmdstr == '!') {
 524                         sed_cmd->invert = 1;
 525                         cmdstr++;
 526
 527                         /* skip whitespace before the command */
 528                         while (isspace(*cmdstr)) cmdstr++;
 529                 }
 530
 531                 /* last part (mandatory) will be a command */
 532                 if (!*cmdstr) bb_error_msg_and_die("missing command");
 533                 sed_cmd->cmd = *(cmdstr++);
 534                 cmdstr = parse_cmd_args(sed_cmd, cmdstr);
 535
 536                 /* Add the command to the command array */
 537                 sed_cmd_tail->next = sed_cmd;
 538                 sed_cmd_tail = sed_cmd_tail->next;
 539         }
 540
 541         /* If we glued multiple lines together, free the memory. */
 542         if(add_cmd_line) {
 543                 free(add_cmd_line);
 544                 add_cmd_line=NULL;
 545         }
 546 }
 547
 548 struct pipeline {
 549         char *buf;      /* Space to hold string */
 550         int idx;        /* Space used */
 551         int len;        /* Space allocated */
 552 } pipeline;
 553
 554 #define PIPE_GROW 64
 555
 556 void pipe_putc(char c)
 557 {
 558         if(pipeline.idx==pipeline.len) {
 559                 pipeline.buf = xrealloc(pipeline.buf, pipeline.len + PIPE_GROW);
 560                 pipeline.len+=PIPE_GROW;
 561         }
 562         pipeline.buf[pipeline.idx++] = (c);
 563 }
 564
 565 static void do_subst_w_backrefs(const char *line, const char *replace)
 566 {
 567         int i,j;
 568
 569         /* go through the replacement string */
 570         for (i = 0; replace[i]; i++) {
 571                 /* if we find a backreference (\1, \2, etc.) print the backref'ed * text */
 572                 if (replace[i] == '\\' && replace[i+1]>'0' && replace[i+1]<='9') {
 573                         int backref=replace[++i]-'0';
 574
 575                         /* print out the text held in regmatch[backref] */
 576                         if(regmatch[backref].rm_so != -1)
 577                                 for (j = regmatch[backref].rm_so; j < regmatch[backref].rm_eo; j++)
 578                                         pipe_putc(line[j]);
 579                 }
 580
 581                 /* if we find a backslash escaped character, print the character */
 582                 else if (replace[i] == '\\') pipe_putc(replace[++i]);
 583
 584                 /* if we find an unescaped '&' print out the whole matched text. */
 585                 else if (replace[i] == '&')
 586                         for (j = regmatch[0].rm_so; j < regmatch[0].rm_eo; j++)
 587                                 pipe_putc(line[j]);
 588                 /* Otherwise just output the character. */
 589                 else pipe_putc(replace[i]);
 590         }
 591 }
 592
 593 static int do_subst_command(sed_cmd_t * sed_cmd, char **line)
 594 {
 595         char *oldline = *line;
 596         int altered = 0;
 597         int match_count=0;
 598         regex_t *current_regex;
 599
 600         /* Handle empty regex. */
 601         if (sed_cmd->sub_match == NULL) {
 602                 current_regex = previous_regex_ptr;
 603                 if(!current_regex)
 604                         bb_error_msg_and_die("No previous regexp.");
 605         } else previous_regex_ptr = current_regex = sed_cmd->sub_match;
 606
 607         /* Find the first match */
 608         if(REG_NOMATCH==regexec(current_regex, oldline, 10, regmatch, 0))
 609                 return 0;
 610
 611         /* Initialize temporary output buffer. */
 612         pipeline.buf=xmalloc(PIPE_GROW);
 613         pipeline.len=PIPE_GROW;
 614         pipeline.idx=0;
 615
 616         /* Now loop through, substituting for matches */
 617         do {
 618                 int i;
 619
 620                 match_count++;
 621
 622                 /* If we aren't interested in this match, output old line to
 623                    end of match and continue */
 624                 if(sed_cmd->which_match && sed_cmd->which_match!=match_count) {
 625                         for(i=0;i<regmatch[0].rm_eo;i++)
 626                                 pipe_putc(oldline[i]);
 627                         continue;
 628                 }
 629
 630                 /* print everything before the match */
 631                 for (i = 0; i < regmatch[0].rm_so; i++) pipe_putc(oldline[i]);
 632
 633                 /* then print the substitution string */
 634                 do_subst_w_backrefs(oldline, sed_cmd->string);
 635
 636                 /* advance past the match */
 637                 oldline += regmatch[0].rm_eo;
 638                 /* flag that something has changed */
 639                 altered++;
 640
 641                 /* if we're not doing this globally, get out now */
 642                 if (sed_cmd->which_match) break;
 643         } while (*oldline && (regexec(current_regex, oldline, 10, regmatch, 0) != REG_NOMATCH));
 644
 645         /* Copy rest of string into output pipeline */
 646
 647         while(*oldline) pipe_putc(*(oldline++));
 648         pipe_putc(0);
 649
 650         free(*line);
 651         *line = pipeline.buf;
 652         return altered;
 653 }
 654
 655 /* Set command pointer to point to this label.  (Does not handle null label.) */
 656 static sed_cmd_t *branch_to(const char *label)
 657 {
 658         sed_cmd_t *sed_cmd;
 659
 660         for (sed_cmd = sed_cmd_head.next; sed_cmd; sed_cmd = sed_cmd->next) {
 661                 if ((sed_cmd->cmd == ':') && (sed_cmd->string) && (strcmp(sed_cmd->string, label) == 0)) {
 662                         return (sed_cmd);
 663                 }
 664         }
 665         bb_error_msg_and_die("Can't find label for jump to `%s'", label);
 666 }
 667
 668 /* Append copy of string to append buffer */
 669 static void append(char *s)
 670 {
 671         struct append_list *temp=calloc(1,sizeof(struct append_list));
 672
 673         if(append_head)
 674                 append_tail=(append_tail->next=temp);
 675         else append_head=append_tail=temp;
 676         temp->string=strdup(s);
 677 }
 678
 679 static void flush_append(void)
 680 {
 681         /* Output appended lines. */
 682         while(append_head) {
 683                 puts(append_head->string);
 684                 append_tail=append_head->next;
 685                 free(append_head->string);
 686                 free(append_head);
 687                 append_head=append_tail;
 688         }
 689         append_head=append_tail=NULL;
 690 }
 691
 692 /* Get next line of input, flushing append buffer and noting if we hit EOF
 693  * without a newline on the last line.
 694  */
 695 static char *get_next_line(FILE * file, int *no_newline)
 696 {
 697         char *temp;
 698         int len;
 699
 700         flush_append();
 701         temp=bb_get_line_from_file(file);
 702         if(temp) {
 703                 len=strlen(temp);
 704                 if(len && temp[len-1]=='\n') temp[len-1]=0;
 705                 else *no_newline=1;
 706         }
 707
 708         return temp;
 709 }
 710
 711 /* Output line of text.  missing_newline means the last line output did not
 712    end with a newline.  no_newline means this line does not end with a
 713    newline. */
 714
 715 static int puts_maybe_newline(char *s, FILE *file, int missing_newline, int no_newline)
 716 {
 717         if(missing_newline) fputc('\n',file);
 718         fputs(s,file);
 719         if(!no_newline) fputc('\n',file);
 720
 721         return no_newline;
 722 }
 723
 724 #define sed_puts(s,n) missing_newline=puts_maybe_newline(s,stdout,missing_newline,n)
 725
 726 static void process_file(FILE * file)
 727 {
 728         char *pattern_space, *next_line, *hold_space=NULL;
 729         static int linenum = 0, missing_newline=0;
 730         int no_newline,next_no_newline=0;
 731
 732         next_line = get_next_line(file,&next_no_newline);
 733
 734         /* go through every line in the file */
 735         for(;;) {
 736                 sed_cmd_t *sed_cmd;
 737                 int substituted=0;
 738
 739                 /* Advance to next line.  Stop if out of lines. */
 740                 if(!(pattern_space=next_line)) break;
 741                 no_newline=next_no_newline;
 742
 743                 /* Read one line in advance so we can act on the last line, the '$' address */
 744                 next_line = get_next_line(file,&next_no_newline);
 745                 linenum++;
 746 restart:
 747                 /* for every line, go through all the commands */
 748                 for (sed_cmd = sed_cmd_head.next; sed_cmd; sed_cmd = sed_cmd->next) {
 749                         int old_matched, matched;
 750
 751                         old_matched = sed_cmd->in_match;
 752
 753                         /* Determine if this command matches this line: */
 754
 755                         /* Are we continuing a previous multi-line match? */
 756
 757                         sed_cmd->in_match = sed_cmd->in_match
 758
 759                         /* Or is no range necessary? */
 760                                 || (!sed_cmd->beg_line && !sed_cmd->end_line
 761                                         && !sed_cmd->beg_match && !sed_cmd->end_match)
 762
 763                         /* Or did we match the start of a numerical range? */
 764                                 || (sed_cmd->beg_line > 0 && (sed_cmd->beg_line == linenum))
 765
 766                         /* Or does this line match our begin address regex? */
 767                                 || (sed_cmd->beg_match &&
 768                                     !regexec(sed_cmd->beg_match, pattern_space, 0, NULL, 0))
 769
 770                         /* Or did we match last line of input? */
 771                                 || (sed_cmd->beg_line == -1 && next_line == NULL);
 772
 773                         /* Snapshot the value */
 774
 775                         matched = sed_cmd->in_match;
 776
 777                         /* Is this line the end of the current match? */
 778
 779                         if(matched) {
 780                                 sed_cmd->in_match = !(
 781                                         /* has the ending line come, or is this a single address command? */
 782                                         (sed_cmd->end_line ?
 783                                                 sed_cmd->end_line==-1 ?
 784                                                         !next_line
 785                                                         : sed_cmd->end_line<=linenum
 786                                                 : !sed_cmd->end_match)
 787                                         /* or does this line matches our last address regex */
 788                                         || (sed_cmd->end_match && old_matched && (regexec(sed_cmd->end_match, pattern_space, 0, NULL, 0) == 0))
 789                                 );
 790                         }
 791
 792                         /* Skip blocks of commands we didn't match. */
 793                         if (sed_cmd->cmd == '{') {
 794                                 if(sed_cmd->invert ? matched : !matched)
 795                                         while(sed_cmd && sed_cmd->cmd!='}') sed_cmd=sed_cmd->next;
 796                                 if(!sed_cmd) bb_error_msg_and_die("Unterminated {");
 797                                 continue;
 798                         }
 799
 800                         /* Okay, so did this line match? */
 801                         if (sed_cmd->invert ? !matched : matched) {
 802                                 /* Update last used regex in case a blank substitute BRE is found */
 803                                 if (sed_cmd->beg_match) {
 804                                         previous_regex_ptr = sed_cmd->beg_match;
 805                                 }
 806
 807                                 /* actual sedding */
 808                                 switch (sed_cmd->cmd) {
 809
 810                                         /* Print line number */
 811                                         case '=':
 812                                                 printf("%d\n", linenum);
 813                                                 break;
 814
 815                                         /* Write the current pattern space up to the first newline */
 816                                         case 'P':
 817                                         {
 818                                                 char *tmp = strchr(pattern_space, '\n');
 819
 820                                                 if (tmp) {
 821                                                         *tmp = '\0';
 822                                                         sed_puts(pattern_space,1);
 823                                                         *tmp = '\n';
 824                                                         break;
 825                                                 }
 826                                                 /* Fall Through */
 827                                         }
 828
 829                                         /* Write the current pattern space to output */
 830                                         case 'p':
 831                                                 sed_puts(pattern_space,no_newline);
 832                                                 break;
 833                                         /* Delete up through first newline */
 834                                         case 'D':
 835                                         {
 836                                                 char *tmp = strchr(pattern_space,'\n');
 837
 838                                                 if(tmp) {
 839                                                         tmp=bb_xstrdup(tmp+1);
 840                                                         free(pattern_space);
 841                                                         pattern_space=tmp;
 842                                                         goto restart;
 843                                                 }
 844                                         }
 845                                         /* discard this line. */
 846                                         case 'd':
 847                                                 goto discard_line;
 848
 849                                         /* Substitute with regex */
 850                                         case 's':
 851                                                 if(do_subst_command(sed_cmd, &pattern_space)) {
 852                                                         substituted|=1;
 853
 854                                                         /* handle p option */
 855                                                         if(sed_cmd->sub_p)
 856                                                                 sed_puts(pattern_space,no_newline);
 857                                                         /* handle w option */
 858                                                         if(sed_cmd->file)
 859                                                                 sed_cmd->no_newline=puts_maybe_newline(pattern_space, sed_cmd->file, sed_cmd->no_newline, no_newline);
 860
 861                                                 }
 862                                                 break;
 863
 864                                         /* Append line to linked list to be printed later */
 865                                         case 'a':
 866                                         {
 867                                                 append(sed_cmd->string);
 868                                                 break;
 869                                         }
 870
 871                                         /* Insert text before this line */
 872                                         case 'i':
 873                                                 sed_puts(sed_cmd->string,1);
 874                                                 break;
 875
 876                                         /* Cut and paste text (replace) */
 877                                         case 'c':
 878                                                 /* Only triggers on last line of a matching range. */
 879                                                 if (!sed_cmd->in_match) sed_puts(sed_cmd->string,1);
 880                                                 goto discard_line;
 881
 882                                         /* Read file, append contents to output */
 883                                         case 'r':
 884                                         {
 885                                                 FILE *outfile;
 886
 887                                                 outfile = fopen(sed_cmd->string, "r");
 888                                                 if (outfile) {
 889                                                         char *line;
 890
 891                                                         while ((line = bb_get_chomped_line_from_file(outfile))
 892                                                                         != NULL)
 893                                                                 append(line);
 894                                                         bb_xprint_and_close_file(outfile);
 895                                                 }
 896
 897                                                 break;
 898                                         }
 899
 900                                         /* Write pattern space to file. */
 901                                         case 'w':
 902                                                 sed_cmd->no_newline=puts_maybe_newline(pattern_space,sed_cmd->file, sed_cmd->no_newline,no_newline);
 903                                                 break;
 904
 905                                         /* Read next line from input */
 906                                         case 'n':
 907                                                 if (!be_quiet)
 908                                                         sed_puts(pattern_space,no_newline);
 909                                                 if (next_line) {
 910                                                         free(pattern_space);
 911                                                         pattern_space = next_line;
 912                                                         no_newline=next_no_newline;
 913                                                         next_line = get_next_line(file,&next_no_newline);
 914                                                         linenum++;
 915                                                         break;
 916                                                 }
 917                                                 /* fall through */
 918
 919                                         /* Quit.  End of script, end of input. */
 920                                         case 'q':
 921                                                 /* Exit the outer while loop */
 922                                                 free(next_line);
 923                                                 next_line = NULL;
 924                                                 goto discard_commands;
 925
 926                                         /* Append the next line to the current line */
 927                                         case 'N':
 928                                         {
 929                                                 /* If no next line, jump to end of script and exit. */
 930                                                 if (next_line == NULL) {
 931                                                         /* Jump to end of script and exit */
 932                                                         free(next_line);
 933                                                         next_line = NULL;
 934                                                         goto discard_line;
 935                                                 /* append next_line, read new next_line. */
 936                                                 } else {
 937                                                         int len=strlen(pattern_space);
 938
 939                                                         pattern_space = realloc(pattern_space, len + strlen(next_line) + 2);
 940                                                         pattern_space[len]='\n';
 941                                                         strcpy(pattern_space+len+1, next_line);
 942                                                         no_newline=next_no_newline;
 943                                                         next_line = get_next_line(file,&next_no_newline);
 944                                                         linenum++;
 945                                                 }
 946                                                 break;
 947                                         }
 948
 949                                         /* Test if substition worked, branch if so. */
 950                                         case 't':
 951                                                 if (!substituted) break;
 952                                                 substituted=0;
 953                                                         /* Fall through */
 954                                         /* Branch to label */
 955                                         case 'b':
 956                                                 if (!sed_cmd->string) goto discard_commands;
 957                                                 else sed_cmd = branch_to(sed_cmd->string);
 958                                                 break;
 959                                         /* Transliterate characters */
 960                                         case 'y':
 961                                         {
 962                                                 int i;
 963
 964                                                 for (i = 0; pattern_space[i]; i++) {
 965                                                         int j;
 966
 967                                                         for (j = 0; sed_cmd->string[j]; j += 2) {
 968                                                                 if (pattern_space[i] == sed_cmd->string[j]) {
 969                                                                         pattern_space[i] = sed_cmd->string[j + 1];
 970                                                                 }
 971                                                         }
 972                                                 }
 973
 974                                                 break;
 975                                         }
 976                                         case 'g':       /* Replace pattern space with hold space */
 977                                                 free(pattern_space);
 978                                                 if (hold_space) {
 979                                                         pattern_space = strdup(hold_space);
 980                                                         no_newline=0;
 981                                                 }
 982                                                 break;
 983                                         case 'G':       /* Append newline and hold space to pattern space */
 984                                         {
 985                                                 int pattern_space_size = 2;
 986                                                 int hold_space_size = 0;
 987
 988                                                 if (pattern_space)
 989                                                         pattern_space_size += strlen(pattern_space);
 990                                                 if (hold_space) hold_space_size = strlen(hold_space);
 991                                                 pattern_space = xrealloc(pattern_space, pattern_space_size + hold_space_size);
 992                                                 if (pattern_space_size == 2) pattern_space[0]=0;
 993                                                 strcat(pattern_space, "\n");
 994                                                 if (hold_space) strcat(pattern_space, hold_space);
 995                                                 no_newline=0;
 996
 997                                                 break;
 998                                         }
 999                                         case 'h':       /* Replace hold space with pattern space */
1000                                                 free(hold_space);
1001                                                 hold_space = strdup(pattern_space);
1002                                                 break;
1003                                         case 'H':       /* Append newline and pattern space to hold space */
1004                                         {
1005                                                 int hold_space_size = 2;
1006                                                 int pattern_space_size = 0;
1007
1008                                                 if (hold_space) hold_space_size += strlen(hold_space);
1009                                                 if (pattern_space)
1010                                                         pattern_space_size = strlen(pattern_space);
1011                                                 hold_space = xrealloc(hold_space,
1012                                                                                         hold_space_size + pattern_space_size);
1013
1014                                                 if (hold_space_size == 2) hold_space[0]=0;
1015                                                 strcat(hold_space, "\n");
1016                                                 if (pattern_space) strcat(hold_space, pattern_space);
1017
1018                                                 break;
1019                                         }
1020                                         case 'x': /* Exchange hold and pattern space */
1021                                         {
1022                                                 char *tmp = pattern_space;
1023                                                 pattern_space = hold_space;
1024                                                 no_newline=0;
1025                                                 hold_space = tmp;
1026                                                 break;
1027                                         }
1028                                 }
1029                         }
1030                 }
1031
1032                 /*
1033                  * exit point from sedding...
1034                  */
1035 discard_commands:
1036                 /* we will print the line unless we were told to be quiet ('-n')
1037                    or if the line was suppressed (ala 'd'elete) */
1038                 if (!be_quiet) sed_puts(pattern_space,no_newline);
1039
1040                 /* Delete and such jump here. */
1041 discard_line:
1042                 flush_append();
1043                 free(pattern_space);
1044         }
1045 }
1046
1047 /* It is possible to have a command line argument with embedded
1048    newlines.  This counts as multiple command lines. */
1049
1050 static void add_cmd_block(char *cmdstr)
1051 {
1052         int go=1;
1053         char *temp=bb_xstrdup(cmdstr),*temp2=temp;
1054
1055         while(go) {
1056                 int len=strcspn(temp2,"\n");
1057                 if(!temp2[len]) go=0;
1058                 else temp2[len]=0;
1059                 add_cmd(temp2);
1060                 temp2+=len+1;
1061         }
1062         free(temp);
1063 }
1064
1065 extern int sed_main(int argc, char **argv)
1066 {
1067         int opt, status = EXIT_SUCCESS;
1068
1069 #ifdef CONFIG_FEATURE_CLEAN_UP
1070         /* destroy command strings on exit */
1071         if (atexit(free_and_close_stuff) == -1)
1072                 bb_perror_msg_and_die("atexit");
1073 #endif
1074
1075         /* do normal option parsing */
1076         while ((opt = getopt(argc, argv, "ne:f:")) > 0) {
1077                 switch (opt) {
1078                 case 'n':
1079                         be_quiet++;
1080                         break;
1081                 case 'e':
1082                         add_cmd_block(optarg);
1083                         break;
1084                 case 'f':
1085                 {
1086                         FILE *cmdfile;
1087                         char *line;
1088
1089                         cmdfile = bb_xfopen(optarg, "r");
1090
1091                         while ((line = bb_get_chomped_line_from_file(cmdfile))
1092                                  != NULL) {
1093                                 add_cmd(line);
1094                                 free(line);
1095                         }
1096                         bb_xprint_and_close_file(cmdfile);
1097
1098                         break;
1099                 }
1100                 default:
1101                         bb_show_usage();
1102                 }
1103         }
1104
1105         /* if we didn't get a pattern from a -e and no command file was specified,
1106          * argv[optind] should be the pattern. no pattern, no worky */
1107         if (sed_cmd_head.next == NULL) {
1108                 if (argv[optind] == NULL)
1109                         bb_show_usage();
1110                 else
1111                         add_cmd_block(argv[optind++]);
1112         }
1113         /* Flush any unfinished commands. */
1114         add_cmd("");
1115
1116         /* argv[(optind)..(argc-1)] should be names of file to process. If no
1117          * files were specified or '-' was specified, take input from stdin.
1118          * Otherwise, we process all the files specified. */
1119         if (argv[optind] == NULL) {
1120                 process_file(stdin);
1121         } else {
1122                 int i;
1123                 FILE *file;
1124
1125                 for (i = optind; i < argc; i++) {
1126                         if(!strcmp(argv[i], "-")) {
1127                                 process_file(stdin);
1128                         } else {
1129                                 file = bb_wfopen(argv[i], "r");
1130                                 if (file) {
1131                                         process_file(file);
1132                                         fclose(file);
1133                                 } else {
1134                                         status = EXIT_FAILURE;
1135                                 }
1136                         }
1137                 }
1138         }
1139
1140         return status;
1141 }