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
   9  * Copyright (C) 2003,2004 by Rob Landley <rob@landley.net>
  10  *
  11  * MAINTAINER: Rob Landley <rob@landley.net>
  12  *
  13  * Licensed under GPLv2, see file LICENSE in this source tree.
  14  */
  15
  16 /* Code overview.
  17  *
  18  * Files are laid out to avoid unnecessary function declarations.  So for
  19  * example, every function add_cmd calls occurs before add_cmd in this file.
  20  *
  21  * add_cmd() is called on each line of sed command text (from a file or from
  22  * the command line).  It calls get_address() and parse_cmd_args().  The
  23  * resulting sed_cmd_t structures are appended to a linked list
  24  * (G.sed_cmd_head/G.sed_cmd_tail).
  25  *
  26  * add_input_file() adds a FILE* to the list of input files.  We need to
  27  * know all input sources ahead of time to find the last line for the $ match.
  28  *
  29  * process_files() does actual sedding, reading data lines from each input FILE*
  30  * (which could be stdin) and applying the sed command list (sed_cmd_head) to
  31  * each of the resulting lines.
  32  *
  33  * sed_main() is where external code calls into this, with a command line.
  34  */
  35
  36 /* Supported features and commands in this version of sed:
  37  *
  38  * - comments ('#')
  39  * - address matching: num|/matchstr/[,num|/matchstr/|$]command
  40  * - commands: (p)rint, (d)elete, (s)ubstitue (with g & I flags)
  41  * - edit commands: (a)ppend, (i)nsert, (c)hange
  42  * - file commands: (r)ead
  43  * - backreferences in substitution expressions (\0, \1, \2...\9)
  44  * - grouped commands: {cmd1;cmd2}
  45  * - transliteration (y/source-chars/dest-chars/)
  46  * - pattern space hold space storing / swapping (g, h, x)
  47  * - labels / branching (: label, b, t, T)
  48  *
  49  * (Note: Specifying an address (range) to match is *optional*; commands
  50  * default to the whole pattern space if no specific address match was
  51  * requested.)
  52  *
  53  * Todo:
  54  * - Create a wrapper around regex to make libc's regex conform with sed
  55  *
  56  * Reference http://www.opengroup.org/onlinepubs/007904975/utilities/sed.html
  57  */
  58
  59 //usage:#define sed_trivial_usage
  60 //usage:       "[-inr] [-f FILE]... [-e CMD]... [FILE]...\n"
  61 //usage:       "or: sed [-inr] CMD [FILE]..."
  62 //usage:#define sed_full_usage "\n\n"
  63 //usage:       "        -e CMD  Add CMD to sed commands to be executed"
  64 //usage:     "\n        -f FILE Add FILE contents to sed commands to be executed"
  65 //usage:     "\n        -i      Edit files in-place (else sends result to stdout)"
  66 //usage:     "\n        -n      Suppress automatic printing of pattern space"
  67 //usage:     "\n        -r      Use extended regex syntax"
  68 //usage:     "\n"
  69 //usage:     "\nIf no -e or -f, the first non-option argument is the sed command string."
  70 //usage:     "\nRemaining arguments are input files (stdin if none)."
  71 //usage:
  72 //usage:#define sed_example_usage
  73 //usage:       "$ echo \"foo\" | sed -e 's/f[a-zA-Z]o/bar/g'\n"
  74 //usage:       "bar\n"
  75
  76 #include "libbb.h"
  77 #include "xregex.h"
  78
  79 #if 0
  80 # define dbg(...) bb_error_msg(__VA_ARGS__)
  81 #else
  82 # define dbg(...) ((void)0)
  83 #endif
  84
  85
  86 enum {
  87         OPT_in_place = 1 << 0,
  88 };
  89
  90 /* Each sed command turns into one of these structures. */
  91 typedef struct sed_cmd_s {
  92         /* Ordered by alignment requirements: currently 36 bytes on x86 */
  93         struct sed_cmd_s *next; /* Next command (linked list, NULL terminated) */
  94
  95         /* address storage */
  96         regex_t *beg_match;     /* sed -e '/match/cmd' */
  97         regex_t *end_match;     /* sed -e '/match/,/end_match/cmd' */
  98         regex_t *sub_match;     /* For 's/sub_match/string/' */
  99         int beg_line;           /* 'sed 1p'   0 == apply commands to all lines */
 100         int beg_line_orig;      /* copy of the above, needed for -i */
 101         int end_line;           /* 'sed 1,3p' 0 == one line only. -1 = last line ($) */
 102
 103         FILE *sw_file;          /* File (sw) command writes to, -1 for none. */
 104         char *string;           /* Data string for (saicytb) commands. */
 105
 106         unsigned which_match;   /* (s) Which match to replace (0 for all) */
 107
 108         /* Bitfields (gcc won't group them if we don't) */
 109         unsigned invert:1;      /* the '!' after the address */
 110         unsigned in_match:1;    /* Next line also included in match? */
 111         unsigned sub_p:1;       /* (s) print option */
 112
 113         char sw_last_char;      /* Last line written by (sw) had no '\n' */
 114
 115         /* GENERAL FIELDS */
 116         char cmd;               /* The command char: abcdDgGhHilnNpPqrstwxy:={} */
 117 } sed_cmd_t;
 118
 119 static const char semicolon_whitespace[] ALIGN1 = "; \n\r\t\v";
 120
 121 struct globals {
 122         /* options */
 123         int be_quiet, regex_type;
 124         FILE *nonstdout;
 125         char *outname, *hold_space;
 126
 127         /* List of input files */
 128         int input_file_count, current_input_file;
 129         FILE **input_file_list;
 130
 131         regmatch_t regmatch[10];
 132         regex_t *previous_regex_ptr;
 133
 134         /* linked list of sed commands */
 135         sed_cmd_t *sed_cmd_head, **sed_cmd_tail;
 136
 137         /* Linked list of append lines */
 138         llist_t *append_head;
 139
 140         char *add_cmd_line;
 141
 142         struct pipeline {
 143                 char *buf;  /* Space to hold string */
 144                 int idx;    /* Space used */
 145                 int len;    /* Space allocated */
 146         } pipeline;
 147 } FIX_ALIASING;
 148 #define G (*(struct globals*)&bb_common_bufsiz1)
 149 struct BUG_G_too_big {
 150         char BUG_G_too_big[sizeof(G) <= COMMON_BUFSIZE ? 1 : -1];
 151 };
 152 #define INIT_G() do { \
 153         G.sed_cmd_tail = &G.sed_cmd_head; \
 154 } while (0)
 155
 156
 157 #if ENABLE_FEATURE_CLEAN_UP
 158 static void sed_free_and_close_stuff(void)
 159 {
 160         sed_cmd_t *sed_cmd = G.sed_cmd_head;
 161
 162         llist_free(G.append_head, free);
 163
 164         while (sed_cmd) {
 165                 sed_cmd_t *sed_cmd_next = sed_cmd->next;
 166
 167                 if (sed_cmd->sw_file)
 168                         xprint_and_close_file(sed_cmd->sw_file);
 169
 170                 if (sed_cmd->beg_match) {
 171                         regfree(sed_cmd->beg_match);
 172                         free(sed_cmd->beg_match);
 173                 }
 174                 if (sed_cmd->end_match) {
 175                         regfree(sed_cmd->end_match);
 176                         free(sed_cmd->end_match);
 177                 }
 178                 if (sed_cmd->sub_match) {
 179                         regfree(sed_cmd->sub_match);
 180                         free(sed_cmd->sub_match);
 181                 }
 182                 free(sed_cmd->string);
 183                 free(sed_cmd);
 184                 sed_cmd = sed_cmd_next;
 185         }
 186
 187         free(G.hold_space);
 188
 189         while (G.current_input_file < G.input_file_count)
 190                 fclose(G.input_file_list[G.current_input_file++]);
 191 }
 192 #else
 193 void sed_free_and_close_stuff(void);
 194 #endif
 195
 196 /* If something bad happens during -i operation, delete temp file */
 197
 198 static void cleanup_outname(void)
 199 {
 200         if (G.outname) unlink(G.outname);
 201 }
 202
 203 /* strcpy, replacing "\from" with 'to'. If to is NUL, replacing "\any" with 'any' */
 204
 205 static void parse_escapes(char *dest, const char *string, int len, char from, char to)
 206 {
 207         int i = 0;
 208
 209         while (i < len) {
 210                 if (string[i] == '\\') {
 211                         if (!to || string[i+1] == from) {
 212                                 *dest++ = to ? to : string[i+1];
 213                                 i += 2;
 214                                 continue;
 215                         }
 216                         *dest++ = string[i++];
 217                 }
 218                 /* TODO: is it safe wrt a string with trailing '\\' ? */
 219                 *dest++ = string[i++];
 220         }
 221         *dest = '\0';
 222 }
 223
 224 static char *copy_parsing_escapes(const char *string, int len)
 225 {
 226         const char *s;
 227         char *dest = xmalloc(len + 1);
 228
 229         /* sed recognizes \n */
 230         /* GNU sed also recognizes \t and \r */
 231         for (s = "\nn\tt\rr"; *s; s += 2) {
 232                 parse_escapes(dest, string, len, s[1], s[0]);
 233                 string = dest;
 234                 len = strlen(dest);
 235         }
 236         return dest;
 237 }
 238
 239
 240 /*
 241  * index_of_next_unescaped_regexp_delim - walks left to right through a string
 242  * beginning at a specified index and returns the index of the next regular
 243  * expression delimiter (typically a forward slash ('/')) not preceded by
 244  * a backslash ('\').  A negative delimiter disables square bracket checking.
 245  */
 246 static int index_of_next_unescaped_regexp_delim(int delimiter, const char *str)
 247 {
 248         int bracket = -1;
 249         int escaped = 0;
 250         int idx = 0;
 251         char ch;
 252
 253         if (delimiter < 0) {
 254                 bracket--;
 255                 delimiter = -delimiter;
 256         }
 257
 258         for (; (ch = str[idx]) != '\0'; idx++) {
 259                 if (bracket >= 0) {
 260                         if (ch == ']'
 261                          && !(bracket == idx - 1 || (bracket == idx - 2 && str[idx - 1] == '^'))
 262                         ) {
 263                                 bracket = -1;
 264                         }
 265                 } else if (escaped)
 266                         escaped = 0;
 267                 else if (ch == '\\')
 268                         escaped = 1;
 269                 else if (bracket == -1 && ch == '[')
 270                         bracket = idx;
 271                 else if (ch == delimiter)
 272                         return idx;
 273         }
 274
 275         /* if we make it to here, we've hit the end of the string */
 276         bb_error_msg_and_die("unmatched '%c'", delimiter);
 277 }
 278
 279 /*
 280  *  Returns the index of the third delimiter
 281  */
 282 static int parse_regex_delim(const char *cmdstr, char **match, char **replace)
 283 {
 284         const char *cmdstr_ptr = cmdstr;
 285         unsigned char delimiter;
 286         int idx = 0;
 287
 288         /* verify that the 's' or 'y' is followed by something.  That something
 289          * (typically a 'slash') is now our regexp delimiter... */
 290         if (*cmdstr == '\0')
 291                 bb_error_msg_and_die("bad format in substitution expression");
 292         delimiter = *cmdstr_ptr++;
 293
 294         /* save the match string */
 295         idx = index_of_next_unescaped_regexp_delim(delimiter, cmdstr_ptr);
 296         *match = copy_parsing_escapes(cmdstr_ptr, idx);
 297
 298         /* save the replacement string */
 299         cmdstr_ptr += idx + 1;
 300         idx = index_of_next_unescaped_regexp_delim(- (int)delimiter, cmdstr_ptr);
 301         *replace = copy_parsing_escapes(cmdstr_ptr, idx);
 302
 303         return ((cmdstr_ptr - cmdstr) + idx);
 304 }
 305
 306 /*
 307  * returns the index in the string just past where the address ends.
 308  */
 309 static int get_address(const char *my_str, int *linenum, regex_t ** regex)
 310 {
 311         const char *pos = my_str;
 312
 313         if (isdigit(*my_str)) {
 314                 *linenum = strtol(my_str, (char**)&pos, 10);
 315                 /* endstr shouldnt ever equal NULL */
 316         } else if (*my_str == '$') {
 317                 *linenum = -1;
 318                 pos++;
 319         } else if (*my_str == '/' || *my_str == '\\') {
 320                 int next;
 321                 char delimiter;
 322                 char *temp;
 323
 324                 delimiter = '/';
 325                 if (*my_str == '\\')
 326                         delimiter = *++pos;
 327                 next = index_of_next_unescaped_regexp_delim(delimiter, ++pos);
 328                 temp = copy_parsing_escapes(pos, next);
 329                 *regex = xzalloc(sizeof(regex_t));
 330                 xregcomp(*regex, temp, G.regex_type|REG_NEWLINE);
 331                 free(temp);
 332                 /* Move position to next character after last delimiter */
 333                 pos += (next+1);
 334         }
 335         return pos - my_str;
 336 }
 337
 338 /* Grab a filename.  Whitespace at start is skipped, then goes to EOL. */
 339 static int parse_file_cmd(/*sed_cmd_t *sed_cmd,*/ const char *filecmdstr, char **retval)
 340 {
 341         int start = 0, idx, hack = 0;
 342
 343         /* Skip whitespace, then grab filename to end of line */
 344         while (isspace(filecmdstr[start]))
 345                 start++;
 346         idx = start;
 347         while (filecmdstr[idx] && filecmdstr[idx] != '\n')
 348                 idx++;
 349
 350         /* If lines glued together, put backslash back. */
 351         if (filecmdstr[idx] == '\n')
 352                 hack = 1;
 353         if (idx == start)
 354                 bb_error_msg_and_die("empty filename");
 355         *retval = xstrndup(filecmdstr+start, idx-start+hack+1);
 356         if (hack)
 357                 (*retval)[idx] = '\\';
 358
 359         return idx;
 360 }
 361
 362 static int parse_subst_cmd(sed_cmd_t *sed_cmd, const char *substr)
 363 {
 364         int cflags = G.regex_type;
 365         char *match;
 366         int idx;
 367
 368         /*
 369          * A substitution command should look something like this:
 370          *    s/match/replace/ #gIpw
 371          *    ||     |        |||
 372          *    mandatory       optional
 373          */
 374         idx = parse_regex_delim(substr, &match, &sed_cmd->string);
 375
 376         /* determine the number of back references in the match string */
 377         /* Note: we compute this here rather than in the do_subst_command()
 378          * function to save processor time, at the expense of a little more memory
 379          * (4 bits) per sed_cmd */
 380
 381         /* process the flags */
 382
 383         sed_cmd->which_match = 1;
 384         while (substr[++idx]) {
 385                 /* Parse match number */
 386                 if (isdigit(substr[idx])) {
 387                         if (match[0] != '^') {
 388                                 /* Match 0 treated as all, multiple matches we take the last one. */
 389                                 const char *pos = substr + idx;
 390 /* FIXME: error check? */
 391                                 sed_cmd->which_match = (unsigned)strtol(substr+idx, (char**) &pos, 10);
 392                                 idx = pos - substr;
 393                         }
 394                         continue;
 395                 }
 396                 /* Skip spaces */
 397                 if (isspace(substr[idx]))
 398                         continue;
 399
 400                 switch (substr[idx]) {
 401                 /* Replace all occurrences */
 402                 case 'g':
 403                         if (match[0] != '^')
 404                                 sed_cmd->which_match = 0;
 405                         break;
 406                 /* Print pattern space */
 407                 case 'p':
 408                         sed_cmd->sub_p = 1;
 409                         break;
 410                 /* Write to file */
 411                 case 'w':
 412                 {
 413                         char *temp;
 414                         idx += parse_file_cmd(/*sed_cmd,*/ substr+idx, &temp);
 415                         break;
 416                 }
 417                 /* Ignore case (gnu exension) */
 418                 case 'I':
 419                         cflags |= REG_ICASE;
 420                         break;
 421                 /* Comment */
 422                 case '#':
 423                         // while (substr[++idx]) continue;
 424                         idx += strlen(substr + idx); // same
 425                         /* Fall through */
 426                 /* End of command */
 427                 case ';':
 428                 case '}':
 429                         goto out;
 430                 default:
 431                         bb_error_msg_and_die("bad option in substitution expression");
 432                 }
 433         }
 434  out:
 435         /* compile the match string into a regex */
 436         if (*match != '\0') {
 437                 /* If match is empty, we use last regex used at runtime */
 438                 sed_cmd->sub_match = xzalloc(sizeof(regex_t));
 439                 dbg("xregcomp('%s',%x)", match, cflags);
 440                 xregcomp(sed_cmd->sub_match, match, cflags);
 441                 dbg("regcomp ok");
 442         }
 443         free(match);
 444
 445         return idx;
 446 }
 447
 448 /*
 449  *  Process the commands arguments
 450  */
 451 static const char *parse_cmd_args(sed_cmd_t *sed_cmd, const char *cmdstr)
 452 {
 453         static const char cmd_letters[] = "saicrw:btTydDgGhHlnNpPqx={}";
 454         enum {
 455                 IDX_s = 0,
 456                 IDX_a,
 457                 IDX_i,
 458                 IDX_c,
 459                 IDX_r,
 460                 IDX_w,
 461                 IDX_colon,
 462                 IDX_b,
 463                 IDX_t,
 464                 IDX_T,
 465                 IDX_y,
 466                 IDX_d,
 467                 IDX_D,
 468                 IDX_g,
 469                 IDX_G,
 470                 IDX_h,
 471                 IDX_H,
 472                 IDX_l,
 473                 IDX_n,
 474                 IDX_N,
 475                 IDX_p,
 476                 IDX_P,
 477                 IDX_q,
 478                 IDX_x,
 479                 IDX_equal,
 480                 IDX_lbrace,
 481                 IDX_rbrace,
 482                 IDX_nul
 483         };
 484         struct chk { char chk[sizeof(cmd_letters)-1 == IDX_nul ? 1 : -1]; };
 485
 486         unsigned idx = strchrnul(cmd_letters, sed_cmd->cmd) - cmd_letters;
 487
 488         /* handle (s)ubstitution command */
 489         if (idx == IDX_s) {
 490                 cmdstr += parse_subst_cmd(sed_cmd, cmdstr);
 491         }
 492         /* handle edit cmds: (a)ppend, (i)nsert, and (c)hange */
 493         else if (idx <= IDX_c) { /* a,i,c */
 494                 if ((sed_cmd->end_line || sed_cmd->end_match) && sed_cmd->cmd != 'c')
 495                         bb_error_msg_and_die("only a beginning address can be specified for edit commands");
 496                 for (;;) {
 497                         if (*cmdstr == '\n' || *cmdstr == '\\') {
 498                                 cmdstr++;
 499                                 break;
 500                         }
 501                         if (!isspace(*cmdstr))
 502                                 break;
 503                         cmdstr++;
 504                 }
 505                 sed_cmd->string = xstrdup(cmdstr);
 506                 /* "\anychar" -> "anychar" */
 507                 parse_escapes(sed_cmd->string, sed_cmd->string, strlen(cmdstr), '\0', '\0');
 508                 cmdstr += strlen(cmdstr);
 509         }
 510         /* handle file cmds: (r)ead */
 511         else if (idx <= IDX_w) { /* r,w */
 512                 if (sed_cmd->end_line || sed_cmd->end_match)
 513                         bb_error_msg_and_die("command only uses one address");
 514                 cmdstr += parse_file_cmd(/*sed_cmd,*/ cmdstr, &sed_cmd->string);
 515                 if (sed_cmd->cmd == 'w') {
 516                         sed_cmd->sw_file = xfopen_for_write(sed_cmd->string);
 517                         sed_cmd->sw_last_char = '\n';
 518                 }
 519         }
 520         /* handle branch commands */
 521         else if (idx <= IDX_T) { /* :,b,t,T */
 522                 int length;
 523
 524                 cmdstr = skip_whitespace(cmdstr);
 525                 length = strcspn(cmdstr, semicolon_whitespace);
 526                 if (length) {
 527                         sed_cmd->string = xstrndup(cmdstr, length);
 528                         cmdstr += length;
 529                 }
 530         }
 531         /* translation command */
 532         else if (idx == IDX_y) {
 533                 char *match, *replace;
 534                 int i = cmdstr[0];
 535
 536                 cmdstr += parse_regex_delim(cmdstr, &match, &replace)+1;
 537                 /* \n already parsed, but \delimiter needs unescaping. */
 538                 parse_escapes(match, match, strlen(match), i, i);
 539                 parse_escapes(replace, replace, strlen(replace), i, i);
 540
 541                 sed_cmd->string = xzalloc((strlen(match) + 1) * 2);
 542                 for (i = 0; match[i] && replace[i]; i++) {
 543                         sed_cmd->string[i*2] = match[i];
 544                         sed_cmd->string[i*2+1] = replace[i];
 545                 }
 546                 free(match);
 547                 free(replace);
 548         }
 549         /* if it wasnt a single-letter command that takes no arguments
 550          * then it must be an invalid command.
 551          */
 552         else if (idx >= IDX_nul) { /* not d,D,g,G,h,H,l,n,N,p,P,q,x,=,{,} */
 553                 bb_error_msg_and_die("unsupported command %c", sed_cmd->cmd);
 554         }
 555
 556         /* give back whatever's left over */
 557         return cmdstr;
 558 }
 559
 560
 561 /* Parse address+command sets, skipping comment lines. */
 562
 563 static void add_cmd(const char *cmdstr)
 564 {
 565         sed_cmd_t *sed_cmd;
 566         unsigned len, n;
 567
 568         /* Append this line to any unfinished line from last time. */
 569         if (G.add_cmd_line) {
 570                 char *tp = xasprintf("%s\n%s", G.add_cmd_line, cmdstr);
 571                 free(G.add_cmd_line);
 572                 cmdstr = G.add_cmd_line = tp;
 573         }
 574
 575         /* If this line ends with unescaped backslash, request next line. */
 576         n = len = strlen(cmdstr);
 577         while (n && cmdstr[n-1] == '\\')
 578                 n--;
 579         if ((len - n) & 1) { /* if odd number of trailing backslashes */
 580                 if (!G.add_cmd_line)
 581                         G.add_cmd_line = xstrdup(cmdstr);
 582                 G.add_cmd_line[len-1] = '\0';
 583                 return;
 584         }
 585
 586         /* Loop parsing all commands in this line. */
 587         while (*cmdstr) {
 588                 /* Skip leading whitespace and semicolons */
 589                 cmdstr += strspn(cmdstr, semicolon_whitespace);
 590
 591                 /* If no more commands, exit. */
 592                 if (!*cmdstr) break;
 593
 594                 /* if this is a comment, jump past it and keep going */
 595                 if (*cmdstr == '#') {
 596                         /* "#n" is the same as using -n on the command line */
 597                         if (cmdstr[1] == 'n')
 598                                 G.be_quiet++;
 599                         cmdstr = strpbrk(cmdstr, "\n\r");
 600                         if (!cmdstr) break;
 601                         continue;
 602                 }
 603
 604                 /* parse the command
 605                  * format is: [addr][,addr][!]cmd
 606                  *            |----||-----||-|
 607                  *            part1 part2  part3
 608                  */
 609
 610                 sed_cmd = xzalloc(sizeof(sed_cmd_t));
 611
 612                 /* first part (if present) is an address: either a '$', a number or a /regex/ */
 613                 cmdstr += get_address(cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
 614                 sed_cmd->beg_line_orig = sed_cmd->beg_line;
 615
 616                 /* second part (if present) will begin with a comma */
 617                 if (*cmdstr == ',') {
 618                         int idx;
 619
 620                         cmdstr++;
 621                         idx = get_address(cmdstr, &sed_cmd->end_line, &sed_cmd->end_match);
 622                         if (!idx)
 623                                 bb_error_msg_and_die("no address after comma");
 624                         cmdstr += idx;
 625                 }
 626
 627                 /* skip whitespace before the command */
 628                 cmdstr = skip_whitespace(cmdstr);
 629
 630                 /* Check for inversion flag */
 631                 if (*cmdstr == '!') {
 632                         sed_cmd->invert = 1;
 633                         cmdstr++;
 634
 635                         /* skip whitespace before the command */
 636                         cmdstr = skip_whitespace(cmdstr);
 637                 }
 638
 639                 /* last part (mandatory) will be a command */
 640                 if (!*cmdstr)
 641                         bb_error_msg_and_die("missing command");
 642                 sed_cmd->cmd = *cmdstr++;
 643                 cmdstr = parse_cmd_args(sed_cmd, cmdstr);
 644
 645                 /* Add the command to the command array */
 646                 *G.sed_cmd_tail = sed_cmd;
 647                 G.sed_cmd_tail = &sed_cmd->next;
 648         }
 649
 650         /* If we glued multiple lines together, free the memory. */
 651         free(G.add_cmd_line);
 652         G.add_cmd_line = NULL;
 653 }
 654
 655 /* Append to a string, reallocating memory as necessary. */
 656
 657 #define PIPE_GROW 64
 658
 659 static void pipe_putc(char c)
 660 {
 661         if (G.pipeline.idx == G.pipeline.len) {
 662                 G.pipeline.buf = xrealloc(G.pipeline.buf,
 663                                 G.pipeline.len + PIPE_GROW);
 664                 G.pipeline.len += PIPE_GROW;
 665         }
 666         G.pipeline.buf[G.pipeline.idx++] = c;
 667 }
 668
 669 static void do_subst_w_backrefs(char *line, char *replace)
 670 {
 671         int i, j;
 672
 673         /* go through the replacement string */
 674         for (i = 0; replace[i]; i++) {
 675                 /* if we find a backreference (\1, \2, etc.) print the backref'ed * text */
 676                 if (replace[i] == '\\') {
 677                         unsigned backref = replace[++i] - '0';
 678                         if (backref <= 9) {
 679                                 /* print out the text held in G.regmatch[backref] */
 680                                 if (G.regmatch[backref].rm_so != -1) {
 681                                         j = G.regmatch[backref].rm_so;
 682                                         while (j < G.regmatch[backref].rm_eo)
 683                                                 pipe_putc(line[j++]);
 684                                 }
 685                                 continue;
 686                         }
 687                         /* I _think_ it is impossible to get '\' to be
 688                          * the last char in replace string. Thus we dont check
 689                          * for replace[i] == NUL. (counterexample anyone?) */
 690                         /* if we find a backslash escaped character, print the character */
 691                         pipe_putc(replace[i]);
 692                         continue;
 693                 }
 694                 /* if we find an unescaped '&' print out the whole matched text. */
 695                 if (replace[i] == '&') {
 696                         j = G.regmatch[0].rm_so;
 697                         while (j < G.regmatch[0].rm_eo)
 698                                 pipe_putc(line[j++]);
 699                         continue;
 700                 }
 701                 /* Otherwise just output the character. */
 702                 pipe_putc(replace[i]);
 703         }
 704 }
 705
 706 static int do_subst_command(sed_cmd_t *sed_cmd, char **line_p)
 707 {
 708         char *line = *line_p;
 709         int altered = 0;
 710         unsigned match_count = 0;
 711         regex_t *current_regex;
 712
 713         current_regex = sed_cmd->sub_match;
 714         /* Handle empty regex. */
 715         if (!current_regex) {
 716                 current_regex = G.previous_regex_ptr;
 717                 if (!current_regex)
 718                         bb_error_msg_and_die("no previous regexp");
 719         }
 720         G.previous_regex_ptr = current_regex;
 721
 722         /* Find the first match */
 723         dbg("matching '%s'", line);
 724         if (REG_NOMATCH == regexec(current_regex, line, 10, G.regmatch, 0)) {
 725                 dbg("no match");
 726                 return 0;
 727         }
 728         dbg("match");
 729
 730         /* Initialize temporary output buffer. */
 731         G.pipeline.buf = xmalloc(PIPE_GROW);
 732         G.pipeline.len = PIPE_GROW;
 733         G.pipeline.idx = 0;
 734
 735         /* Now loop through, substituting for matches */
 736         do {
 737                 int i;
 738
 739                 /* Work around bug in glibc regexec, demonstrated by:
 740                  * echo " a.b" | busybox sed 's [^ .]* x g'
 741                  * The match_count check is so not to break
 742                  * echo "hi" | busybox sed 's/^/!/g'
 743                  */
 744                 if (!G.regmatch[0].rm_so && !G.regmatch[0].rm_eo && match_count) {
 745                         pipe_putc(*line++);
 746                         continue;
 747                 }
 748
 749                 match_count++;
 750
 751                 /* If we aren't interested in this match, output old line to
 752                    end of match and continue */
 753                 if (sed_cmd->which_match
 754                  && (sed_cmd->which_match != match_count)
 755                 ) {
 756                         for (i = 0; i < G.regmatch[0].rm_eo; i++)
 757                                 pipe_putc(*line++);
 758                         continue;
 759                 }
 760
 761                 /* print everything before the match */
 762                 for (i = 0; i < G.regmatch[0].rm_so; i++)
 763                         pipe_putc(line[i]);
 764
 765                 /* then print the substitution string */
 766                 do_subst_w_backrefs(line, sed_cmd->string);
 767
 768                 /* advance past the match */
 769                 line += G.regmatch[0].rm_eo;
 770                 /* flag that something has changed */
 771                 altered++;
 772
 773                 /* if we're not doing this globally, get out now */
 774                 if (sed_cmd->which_match != 0)
 775                         break;
 776
 777                 if (*line == '\0')
 778                         break;
 779
 780 //maybe (G.regmatch[0].rm_eo ? REG_NOTBOL : 0) instead of unconditional REG_NOTBOL?
 781         } while (regexec(current_regex, line, 10, G.regmatch, REG_NOTBOL) != REG_NOMATCH);
 782
 783         /* Copy rest of string into output pipeline */
 784         while (1) {
 785                 char c = *line++;
 786                 pipe_putc(c);
 787                 if (c == '\0')
 788                         break;
 789         }
 790
 791         free(*line_p);
 792         *line_p = G.pipeline.buf;
 793         return altered;
 794 }
 795
 796 /* Set command pointer to point to this label.  (Does not handle null label.) */
 797 static sed_cmd_t *branch_to(char *label)
 798 {
 799         sed_cmd_t *sed_cmd;
 800
 801         for (sed_cmd = G.sed_cmd_head; sed_cmd; sed_cmd = sed_cmd->next) {
 802                 if (sed_cmd->cmd == ':' && sed_cmd->string && !strcmp(sed_cmd->string, label)) {
 803                         return sed_cmd;
 804                 }
 805         }
 806         bb_error_msg_and_die("can't find label for jump to '%s'", label);
 807 }
 808
 809 static void append(char *s)
 810 {
 811         llist_add_to_end(&G.append_head, xstrdup(s));
 812 }
 813
 814 static void flush_append(void)
 815 {
 816         char *data;
 817
 818         /* Output appended lines. */
 819         while ((data = (char *)llist_pop(&G.append_head))) {
 820                 fprintf(G.nonstdout, "%s\n", data);
 821                 free(data);
 822         }
 823 }
 824
 825 static void add_input_file(FILE *file)
 826 {
 827         G.input_file_list = xrealloc_vector(G.input_file_list, 2, G.input_file_count);
 828         G.input_file_list[G.input_file_count++] = file;
 829 }
 830
 831 /* Get next line of input from G.input_file_list, flushing append buffer and
 832  * noting if we ran out of files without a newline on the last line we read.
 833  */
 834 enum {
 835         NO_EOL_CHAR = 1,
 836         LAST_IS_NUL = 2,
 837 };
 838 static char *get_next_line(char *gets_char)
 839 {
 840         char *temp = NULL;
 841         int len;
 842         char gc;
 843
 844         flush_append();
 845
 846         /* will be returned if last line in the file
 847          * doesn't end with either '\n' or '\0' */
 848         gc = NO_EOL_CHAR;
 849         while (G.current_input_file < G.input_file_count) {
 850                 FILE *fp = G.input_file_list[G.current_input_file];
 851                 /* Read line up to a newline or NUL byte, inclusive,
 852                  * return malloc'ed char[]. length of the chunk read
 853                  * is stored in len. NULL if EOF/error */
 854                 temp = bb_get_chunk_from_file(fp, &len);
 855                 if (temp) {
 856                         /* len > 0 here, it's ok to do temp[len-1] */
 857                         char c = temp[len-1];
 858                         if (c == '\n' || c == '\0') {
 859                                 temp[len-1] = '\0';
 860                                 gc = c;
 861                                 if (c == '\0') {
 862                                         int ch = fgetc(fp);
 863                                         if (ch != EOF)
 864                                                 ungetc(ch, fp);
 865                                         else
 866                                                 gc = LAST_IS_NUL;
 867                                 }
 868                         }
 869                         /* else we put NO_EOL_CHAR into *gets_char */
 870                         break;
 871
 872                 /* NB: I had the idea of peeking next file(s) and returning
 873                  * NO_EOL_CHAR only if it is the *last* non-empty
 874                  * input file. But there is a case where this won't work:
 875                  * file1: "a woo\nb woo"
 876                  * file2: "c no\nd no"
 877                  * sed -ne 's/woo/bang/p' input1 input2 => "a bang\nb bang"
 878                  * (note: *no* newline after "b bang"!) */
 879                 }
 880                 /* Close this file and advance to next one */
 881                 fclose(fp);
 882                 G.current_input_file++;
 883         }
 884         *gets_char = gc;
 885         return temp;
 886 }
 887
 888 /* Output line of text. */
 889 /* Note:
 890  * The tricks with NO_EOL_CHAR and last_puts_char are there to emulate gnu sed.
 891  * Without them, we had this:
 892  * echo -n thingy >z1
 893  * echo -n again >z2
 894  * >znull
 895  * sed "s/i/z/" z1 z2 znull | hexdump -vC
 896  * output:
 897  * gnu sed 4.1.5:
 898  * 00000000  74 68 7a 6e 67 79 0a 61  67 61 7a 6e              |thzngy.agazn|
 899  * bbox:
 900  * 00000000  74 68 7a 6e 67 79 61 67  61 7a 6e                 |thzngyagazn|
 901  */
 902 static void puts_maybe_newline(char *s, FILE *file, char *last_puts_char, char last_gets_char)
 903 {
 904         char lpc = *last_puts_char;
 905
 906         /* Need to insert a '\n' between two files because first file's
 907          * last line wasn't terminated? */
 908         if (lpc != '\n' && lpc != '\0') {
 909                 fputc('\n', file);
 910                 lpc = '\n';
 911         }
 912         fputs(s, file);
 913
 914         /* 'x' - just something which is not '\n', '\0' or NO_EOL_CHAR */
 915         if (s[0])
 916                 lpc = 'x';
 917
 918         /* had trailing '\0' and it was last char of file? */
 919         if (last_gets_char == LAST_IS_NUL) {
 920                 fputc('\0', file);
 921                 lpc = 'x'; /* */
 922         } else
 923         /* had trailing '\n' or '\0'? */
 924         if (last_gets_char != NO_EOL_CHAR) {
 925                 fputc(last_gets_char, file);
 926                 lpc = last_gets_char;
 927         }
 928
 929         if (ferror(file)) {
 930                 xfunc_error_retval = 4;  /* It's what gnu sed exits with... */
 931                 bb_error_msg_and_die(bb_msg_write_error);
 932         }
 933         *last_puts_char = lpc;
 934 }
 935
 936 #define sed_puts(s, n) (puts_maybe_newline(s, G.nonstdout, &last_puts_char, n))
 937
 938 static int beg_match(sed_cmd_t *sed_cmd, const char *pattern_space)
 939 {
 940         int retval = sed_cmd->beg_match && !regexec(sed_cmd->beg_match, pattern_space, 0, NULL, 0);
 941         if (retval)
 942                 G.previous_regex_ptr = sed_cmd->beg_match;
 943         return retval;
 944 }
 945
 946 /* Process all the lines in all the files */
 947
 948 static void process_files(void)
 949 {
 950         char *pattern_space, *next_line;
 951         int linenum = 0;
 952         char last_puts_char = '\n';
 953         char last_gets_char, next_gets_char;
 954         sed_cmd_t *sed_cmd;
 955         int substituted;
 956
 957         /* Prime the pump */
 958         next_line = get_next_line(&next_gets_char);
 959
 960         /* Go through every line in each file */
 961  again:
 962         substituted = 0;
 963
 964         /* Advance to next line.  Stop if out of lines. */
 965         pattern_space = next_line;
 966         if (!pattern_space)
 967                 return;
 968         last_gets_char = next_gets_char;
 969
 970         /* Read one line in advance so we can act on the last line,
 971          * the '$' address */
 972         next_line = get_next_line(&next_gets_char);
 973         linenum++;
 974
 975         /* For every line, go through all the commands */
 976  restart:
 977         for (sed_cmd = G.sed_cmd_head; sed_cmd; sed_cmd = sed_cmd->next) {
 978                 int old_matched, matched;
 979
 980                 old_matched = sed_cmd->in_match;
 981
 982                 /* Determine if this command matches this line: */
 983
 984                 dbg("match1:%d", sed_cmd->in_match);
 985                 dbg("match2:%d", (!sed_cmd->beg_line && !sed_cmd->end_line
 986                                 && !sed_cmd->beg_match && !sed_cmd->end_match));
 987                 dbg("match3:%d", (sed_cmd->beg_line > 0
 988                         && (sed_cmd->end_line || sed_cmd->end_match
 989                             ? (sed_cmd->beg_line <= linenum)
 990                             : (sed_cmd->beg_line == linenum)
 991                             )
 992                         ));
 993                 dbg("match4:%d", (beg_match(sed_cmd, pattern_space)));
 994                 dbg("match5:%d", (sed_cmd->beg_line == -1 && next_line == NULL));
 995
 996                 /* Are we continuing a previous multi-line match? */
 997                 sed_cmd->in_match = sed_cmd->in_match
 998                         /* Or is no range necessary? */
 999                         || (!sed_cmd->beg_line && !sed_cmd->end_line
1000                                 && !sed_cmd->beg_match && !sed_cmd->end_match)
1001                         /* Or did we match the start of a numerical range? */
1002                         || (sed_cmd->beg_line > 0
1003                             && (sed_cmd->end_line || sed_cmd->end_match
1004                                   /* note: even if end is numeric and is < linenum too,
1005                                    * GNU sed matches! We match too, therefore we don't
1006                                    * check here that linenum <= end.
1007                                    * Example:
1008                                    * printf '1\n2\n3\n4\n' | sed -n '1{N;N;d};1p;2,3p;3p;4p'
1009                                    * first three input lines are deleted;
1010                                    * 4th line is matched and printed
1011                                    * by "2,3" (!) and by "4" ranges
1012                                    */
1013                                 ? (sed_cmd->beg_line <= linenum)    /* N,end */
1014                                 : (sed_cmd->beg_line == linenum)    /* N */
1015                                 )
1016                             )
1017                         /* Or does this line match our begin address regex? */
1018                         || (beg_match(sed_cmd, pattern_space))
1019                         /* Or did we match last line of input? */
1020                         || (sed_cmd->beg_line == -1 && next_line == NULL);
1021
1022                 /* Snapshot the value */
1023                 matched = sed_cmd->in_match;
1024
1025                 dbg("cmd:'%c' matched:%d beg_line:%d end_line:%d linenum:%d",
1026                         sed_cmd->cmd, matched, sed_cmd->beg_line, sed_cmd->end_line, linenum);
1027
1028                 /* Is this line the end of the current match? */
1029
1030                 if (matched) {
1031                         /* once matched, "n,xxx" range is dead, disabling it */
1032                         if (sed_cmd->beg_line > 0) {
1033                                 sed_cmd->beg_line = -2;
1034                         }
1035                         sed_cmd->in_match = !(
1036                                 /* has the ending line come, or is this a single address command? */
1037                                 (sed_cmd->end_line
1038                                         ? sed_cmd->end_line == -1
1039                                                 ? !next_line
1040                                                 : (sed_cmd->end_line <= linenum)
1041                                         : !sed_cmd->end_match
1042                                 )
1043                                 /* or does this line matches our last address regex */
1044                                 || (sed_cmd->end_match && old_matched
1045                                      && (regexec(sed_cmd->end_match,
1046                                                  pattern_space, 0, NULL, 0) == 0)
1047                                 )
1048                         );
1049                 }
1050
1051                 /* Skip blocks of commands we didn't match */
1052                 if (sed_cmd->cmd == '{') {
1053                         if (sed_cmd->invert ? matched : !matched) {
1054                                 unsigned nest_cnt = 0;
1055                                 while (1) {
1056                                         if (sed_cmd->cmd == '{')
1057                                                 nest_cnt++;
1058                                         if (sed_cmd->cmd == '}') {
1059                                                 nest_cnt--;
1060                                                 if (nest_cnt == 0)
1061                                                         break;
1062                                         }
1063                                         sed_cmd = sed_cmd->next;
1064                                         if (!sed_cmd)
1065                                                 bb_error_msg_and_die("unterminated {");
1066                                 }
1067                         }
1068                         continue;
1069                 }
1070
1071                 /* Okay, so did this line match? */
1072                 if (sed_cmd->invert ? matched : !matched)
1073                         continue; /* no */
1074
1075                 /* Update last used regex in case a blank substitute BRE is found */
1076                 if (sed_cmd->beg_match) {
1077                         G.previous_regex_ptr = sed_cmd->beg_match;
1078                 }
1079
1080                 /* actual sedding */
1081                 dbg("pattern_space:'%s' next_line:'%s' cmd:%c",
1082                                 pattern_space, next_line, sed_cmd->cmd);
1083                 switch (sed_cmd->cmd) {
1084
1085                 /* Print line number */
1086                 case '=':
1087                         fprintf(G.nonstdout, "%d\n", linenum);
1088                         break;
1089
1090                 /* Write the current pattern space up to the first newline */
1091                 case 'P':
1092                 {
1093                         char *tmp = strchr(pattern_space, '\n');
1094                         if (tmp) {
1095                                 *tmp = '\0';
1096                                 /* TODO: explain why '\n' below */
1097                                 sed_puts(pattern_space, '\n');
1098                                 *tmp = '\n';
1099                                 break;
1100                         }
1101                         /* Fall Through */
1102                 }
1103
1104                 /* Write the current pattern space to output */
1105                 case 'p':
1106                         /* NB: we print this _before_ the last line
1107                          * (of current file) is printed. Even if
1108                          * that line is nonterminated, we print
1109                          * '\n' here (gnu sed does the same) */
1110                         sed_puts(pattern_space, '\n');
1111                         break;
1112                 /* Delete up through first newline */
1113                 case 'D':
1114                 {
1115                         char *tmp = strchr(pattern_space, '\n');
1116                         if (tmp) {
1117                                 overlapping_strcpy(pattern_space, tmp + 1);
1118                                 goto restart;
1119                         }
1120                 }
1121                 /* discard this line. */
1122                 case 'd':
1123                         goto discard_line;
1124
1125                 /* Substitute with regex */
1126                 case 's':
1127                         if (!do_subst_command(sed_cmd, &pattern_space))
1128                                 break;
1129                         dbg("do_subst_command succeeeded:'%s'", pattern_space);
1130                         substituted |= 1;
1131
1132                         /* handle p option */
1133                         if (sed_cmd->sub_p)
1134                                 sed_puts(pattern_space, last_gets_char);
1135                         /* handle w option */
1136                         if (sed_cmd->sw_file)
1137                                 puts_maybe_newline(
1138                                         pattern_space, sed_cmd->sw_file,
1139                                         &sed_cmd->sw_last_char, last_gets_char);
1140                         break;
1141
1142                 /* Append line to linked list to be printed later */
1143                 case 'a':
1144                         append(sed_cmd->string);
1145                         break;
1146
1147                 /* Insert text before this line */
1148                 case 'i':
1149                         sed_puts(sed_cmd->string, '\n');
1150                         break;
1151
1152                 /* Cut and paste text (replace) */
1153                 case 'c':
1154                         /* Only triggers on last line of a matching range. */
1155                         if (!sed_cmd->in_match)
1156                                 sed_puts(sed_cmd->string, '\n');
1157                         goto discard_line;
1158
1159                 /* Read file, append contents to output */
1160                 case 'r':
1161                 {
1162                         FILE *rfile;
1163                         rfile = fopen_for_read(sed_cmd->string);
1164                         if (rfile) {
1165                                 char *line;
1166
1167                                 while ((line = xmalloc_fgetline(rfile))
1168                                                 != NULL)
1169                                         append(line);
1170                                 xprint_and_close_file(rfile);
1171                         }
1172
1173                         break;
1174                 }
1175
1176                 /* Write pattern space to file. */
1177                 case 'w':
1178                         puts_maybe_newline(
1179                                 pattern_space, sed_cmd->sw_file,
1180                                 &sed_cmd->sw_last_char, last_gets_char);
1181                         break;
1182
1183                 /* Read next line from input */
1184                 case 'n':
1185                         if (!G.be_quiet)
1186                                 sed_puts(pattern_space, last_gets_char);
1187                         if (next_line) {
1188                                 free(pattern_space);
1189                                 pattern_space = next_line;
1190                                 last_gets_char = next_gets_char;
1191                                 next_line = get_next_line(&next_gets_char);
1192                                 substituted = 0;
1193                                 linenum++;
1194                                 break;
1195                         }
1196                         /* fall through */
1197
1198                 /* Quit.  End of script, end of input. */
1199                 case 'q':
1200                         /* Exit the outer while loop */
1201                         free(next_line);
1202                         next_line = NULL;
1203                         goto discard_commands;
1204
1205                 /* Append the next line to the current line */
1206                 case 'N':
1207                 {
1208                         int len;
1209                         /* If no next line, jump to end of script and exit. */
1210                         /* http://www.gnu.org/software/sed/manual/sed.html:
1211                          * "Most versions of sed exit without printing anything
1212                          * when the N command is issued on the last line of
1213                          * a file. GNU sed prints pattern space before exiting
1214                          * unless of course the -n command switch has been
1215                          * specified. This choice is by design."
1216                          */
1217                         if (next_line == NULL) {
1218                                 //goto discard_line;
1219                                 goto discard_commands; /* GNU behavior */
1220                         }
1221                         /* Append next_line, read new next_line. */
1222                         len = strlen(pattern_space);
1223                         pattern_space = xrealloc(pattern_space, len + strlen(next_line) + 2);
1224                         pattern_space[len] = '\n';
1225                         strcpy(pattern_space + len+1, next_line);
1226                         last_gets_char = next_gets_char;
1227                         next_line = get_next_line(&next_gets_char);
1228                         linenum++;
1229                         break;
1230                 }
1231
1232                 /* Test/branch if substitution occurred */
1233                 case 't':
1234                         if (!substituted) break;
1235                         substituted = 0;
1236                         /* Fall through */
1237                 /* Test/branch if substitution didn't occur */
1238                 case 'T':
1239                         if (substituted) break;
1240                         /* Fall through */
1241                 /* Branch to label */
1242                 case 'b':
1243                         if (!sed_cmd->string) goto discard_commands;
1244                         else sed_cmd = branch_to(sed_cmd->string);
1245                         break;
1246                 /* Transliterate characters */
1247                 case 'y':
1248                 {
1249                         int i, j;
1250                         for (i = 0; pattern_space[i]; i++) {
1251                                 for (j = 0; sed_cmd->string[j]; j += 2) {
1252                                         if (pattern_space[i] == sed_cmd->string[j]) {
1253                                                 pattern_space[i] = sed_cmd->string[j + 1];
1254                                                 break;
1255                                         }
1256                                 }
1257                         }
1258
1259                         break;
1260                 }
1261                 case 'g':       /* Replace pattern space with hold space */
1262                         free(pattern_space);
1263                         pattern_space = xstrdup(G.hold_space ? G.hold_space : "");
1264                         break;
1265                 case 'G':       /* Append newline and hold space to pattern space */
1266                 {
1267                         int pattern_space_size = 2;
1268                         int hold_space_size = 0;
1269
1270                         if (pattern_space)
1271                                 pattern_space_size += strlen(pattern_space);
1272                         if (G.hold_space)
1273                                 hold_space_size = strlen(G.hold_space);
1274                         pattern_space = xrealloc(pattern_space,
1275                                         pattern_space_size + hold_space_size);
1276                         if (pattern_space_size == 2)
1277                                 pattern_space[0] = 0;
1278                         strcat(pattern_space, "\n");
1279                         if (G.hold_space)
1280                                 strcat(pattern_space, G.hold_space);
1281                         last_gets_char = '\n';
1282
1283                         break;
1284                 }
1285                 case 'h':       /* Replace hold space with pattern space */
1286                         free(G.hold_space);
1287                         G.hold_space = xstrdup(pattern_space);
1288                         break;
1289                 case 'H':       /* Append newline and pattern space to hold space */
1290                 {
1291                         int hold_space_size = 2;
1292                         int pattern_space_size = 0;
1293
1294                         if (G.hold_space)
1295                                 hold_space_size += strlen(G.hold_space);
1296                         if (pattern_space)
1297                                 pattern_space_size = strlen(pattern_space);
1298                         G.hold_space = xrealloc(G.hold_space,
1299                                         hold_space_size + pattern_space_size);
1300
1301                         if (hold_space_size == 2)
1302                                 *G.hold_space = 0;
1303                         strcat(G.hold_space, "\n");
1304                         if (pattern_space)
1305                                 strcat(G.hold_space, pattern_space);
1306
1307                         break;
1308                 }
1309                 case 'x': /* Exchange hold and pattern space */
1310                 {
1311                         char *tmp = pattern_space;
1312                         pattern_space = G.hold_space ? G.hold_space : xzalloc(1);
1313                         last_gets_char = '\n';
1314                         G.hold_space = tmp;
1315                         break;
1316                 }
1317                 } /* switch */
1318         } /* for each cmd */
1319
1320         /*
1321          * Exit point from sedding...
1322          */
1323  discard_commands:
1324         /* we will print the line unless we were told to be quiet ('-n')
1325            or if the line was suppressed (ala 'd'elete) */
1326         if (!G.be_quiet)
1327                 sed_puts(pattern_space, last_gets_char);
1328
1329         /* Delete and such jump here. */
1330  discard_line:
1331         flush_append();
1332         free(pattern_space);
1333
1334         goto again;
1335 }
1336
1337 /* It is possible to have a command line argument with embedded
1338  * newlines.  This counts as multiple command lines.
1339  * However, newline can be escaped: 's/e/z\<newline>z/'
1340  * We check for this.
1341  */
1342
1343 static void add_cmd_block(char *cmdstr)
1344 {
1345         char *sv, *eol;
1346
1347         cmdstr = sv = xstrdup(cmdstr);
1348         do {
1349                 eol = strchr(cmdstr, '\n');
1350  next:
1351                 if (eol) {
1352                         /* Count preceding slashes */
1353                         int slashes = 0;
1354                         char *sl = eol;
1355
1356                         while (sl != cmdstr && *--sl == '\\')
1357                                 slashes++;
1358                         /* Odd number of preceding slashes - newline is escaped */
1359                         if (slashes & 1) {
1360                                 overlapping_strcpy(eol - 1, eol);
1361                                 eol = strchr(eol, '\n');
1362                                 goto next;
1363                         }
1364                         *eol = '\0';
1365                 }
1366                 add_cmd(cmdstr);
1367                 cmdstr = eol + 1;
1368         } while (eol);
1369         free(sv);
1370 }
1371
1372 int sed_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1373 int sed_main(int argc UNUSED_PARAM, char **argv)
1374 {
1375         unsigned opt;
1376         llist_t *opt_e, *opt_f;
1377         int status = EXIT_SUCCESS;
1378
1379         INIT_G();
1380
1381         /* destroy command strings on exit */
1382         if (ENABLE_FEATURE_CLEAN_UP) atexit(sed_free_and_close_stuff);
1383
1384         /* Lie to autoconf when it starts asking stupid questions. */
1385         if (argv[1] && !strcmp(argv[1], "--version")) {
1386                 puts("This is not GNU sed version 4.0");
1387                 return 0;
1388         }
1389
1390         /* do normal option parsing */
1391         opt_e = opt_f = NULL;
1392         opt_complementary = "e::f::" /* can occur multiple times */
1393                             "nn"; /* count -n */
1394         /* -i must be first, to match OPT_in_place definition */
1395         opt = getopt32(argv, "irne:f:", &opt_e, &opt_f,
1396                             &G.be_quiet); /* counter for -n */
1397         //argc -= optind;
1398         argv += optind;
1399         if (opt & OPT_in_place) { // -i
1400                 atexit(cleanup_outname);
1401         }
1402         if (opt & 0x2) G.regex_type |= REG_EXTENDED; // -r
1403         //if (opt & 0x4) G.be_quiet++; // -n
1404         while (opt_e) { // -e
1405                 add_cmd_block(llist_pop(&opt_e));
1406         }
1407         while (opt_f) { // -f
1408                 char *line;
1409                 FILE *cmdfile;
1410                 cmdfile = xfopen_for_read(llist_pop(&opt_f));
1411                 while ((line = xmalloc_fgetline(cmdfile)) != NULL) {
1412                         add_cmd(line);
1413                         free(line);
1414                 }
1415                 fclose(cmdfile);
1416         }
1417         /* if we didn't get a pattern from -e or -f, use argv[0] */
1418         if (!(opt & 0x18)) {
1419                 if (!*argv)
1420                         bb_show_usage();
1421                 add_cmd_block(*argv++);
1422         }
1423         /* Flush any unfinished commands. */
1424         add_cmd("");
1425
1426         /* By default, we write to stdout */
1427         G.nonstdout = stdout;
1428
1429         /* argv[0..(argc-1)] should be names of file to process. If no
1430          * files were specified or '-' was specified, take input from stdin.
1431          * Otherwise, we process all the files specified. */
1432         if (argv[0] == NULL) {
1433                 if (opt & OPT_in_place)
1434                         bb_error_msg_and_die(bb_msg_requires_arg, "-i");
1435                 add_input_file(stdin);
1436         } else {
1437                 int i;
1438
1439                 for (i = 0; argv[i]; i++) {
1440                         struct stat statbuf;
1441                         int nonstdoutfd;
1442                         FILE *file;
1443                         sed_cmd_t *sed_cmd;
1444
1445                         if (LONE_DASH(argv[i]) && !(opt & OPT_in_place)) {
1446                                 add_input_file(stdin);
1447                                 process_files();
1448                                 continue;
1449                         }
1450                         file = fopen_or_warn(argv[i], "r");
1451                         if (!file) {
1452                                 status = EXIT_FAILURE;
1453                                 continue;
1454                         }
1455                         add_input_file(file);
1456                         if (!(opt & OPT_in_place)) {
1457                                 continue;
1458                         }
1459
1460                         /* -i: process each FILE separately: */
1461
1462                         G.outname = xasprintf("%sXXXXXX", argv[i]);
1463                         nonstdoutfd = xmkstemp(G.outname);
1464                         G.nonstdout = xfdopen_for_write(nonstdoutfd);
1465
1466                         /* Set permissions/owner of output file */
1467                         fstat(fileno(file), &statbuf);
1468                         /* chmod'ing AFTER chown would preserve suid/sgid bits,
1469                          * but GNU sed 4.2.1 does not preserve them either */
1470                         fchmod(nonstdoutfd, statbuf.st_mode);
1471                         fchown(nonstdoutfd, statbuf.st_uid, statbuf.st_gid);
1472
1473                         process_files();
1474                         fclose(G.nonstdout);
1475                         G.nonstdout = stdout;
1476
1477                         /* unlink(argv[i]); */
1478                         xrename(G.outname, argv[i]);
1479                         free(G.outname);
1480                         G.outname = NULL;
1481
1482                         /* Re-enable disabled range matches */
1483                         for (sed_cmd = G.sed_cmd_head; sed_cmd; sed_cmd = sed_cmd->next) {
1484                                 sed_cmd->beg_line = sed_cmd->beg_line_orig;
1485                         }
1486                 }
1487                 /* Here, to handle "sed 'cmds' nonexistent_file" case we did:
1488                  * if (G.current_input_file >= G.input_file_count)
1489                  *      return status;
1490                  * but it's not needed since process_files() works correctly
1491                  * in this case too. */
1492         }
1493         process_files();
1494
1495         return status;
1496 }