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/|$]command
  40  * - commands: (p)rint, (d)elete, (s)ubstitue (with g & I flags)
  41  * - edit commands: (a)ppend, (i)nsert, (c)hange
  42  * - file commands: (r)ead
  43  * - backreferences in substitution expressions (\0, \1, \2...\9)
  44  * - grouped commands: {cmd1;cmd2}
  45  * - transliteration (y/source-chars/dest-chars/)
  46  * - pattern space hold space storing / swapping (g, h, x)
  47  * - labels / branching (: label, b, t, T)
  48  *
  49  * (Note: Specifying an address (range) to match is *optional*; commands
  50  * default to the whole pattern space if no specific address match was
  51  * requested.)
  52  *
  53  * Todo:
  54  * - Create a wrapper around regex to make libc's regex conform with sed
  55  *
  56  * Reference
  57  * http://www.opengroup.org/onlinepubs/007904975/utilities/sed.html
  58  * http://pubs.opengroup.org/onlinepubs/9699919799/utilities/sed.html
  59  */
  60
  61 //usage:#define sed_trivial_usage
  62 //usage:       "[-inr] [-f FILE]... [-e CMD]... [FILE]...\n"
  63 //usage:       "or: sed [-inr] CMD [FILE]..."
  64 //usage:#define sed_full_usage "\n\n"
  65 //usage:       "        -e CMD  Add CMD to sed commands to be executed"
  66 //usage:     "\n        -f FILE Add FILE contents to sed commands to be executed"
  67 //usage:     "\n        -i[SFX] Edit files in-place (otherwise sends to stdout)"
  68 //usage:     "\n                Optionally back files up, appending SFX"
  69 //usage:     "\n        -n      Suppress automatic printing of pattern space"
  70 //usage:     "\n        -r      Use extended regex syntax"
  71 //usage:     "\n"
  72 //usage:     "\nIf no -e or -f, the first non-option argument is the sed command string."
  73 //usage:     "\nRemaining arguments are input files (stdin if none)."
  74 //usage:
  75 //usage:#define sed_example_usage
  76 //usage:       "$ echo \"foo\" | sed -e 's/f[a-zA-Z]o/bar/g'\n"
  77 //usage:       "bar\n"
  78
  79 #include "libbb.h"
  80 #include "xregex.h"
  81
  82 #if 0
  83 # define dbg(...) bb_error_msg(__VA_ARGS__)
  84 #else
  85 # define dbg(...) ((void)0)
  86 #endif
  87
  88
  89 enum {
  90         OPT_in_place = 1 << 0,
  91 };
  92
  93 /* Each sed command turns into one of these structures. */
  94 typedef struct sed_cmd_s {
  95         /* Ordered by alignment requirements: currently 36 bytes on x86 */
  96         struct sed_cmd_s *next; /* Next command (linked list, NULL terminated) */
  97
  98         /* address storage */
  99         regex_t *beg_match;     /* sed -e '/match/cmd' */
 100         regex_t *end_match;     /* sed -e '/match/,/end_match/cmd' */
 101         regex_t *sub_match;     /* For 's/sub_match/string/' */
 102         int beg_line;           /* 'sed 1p'   0 == apply commands to all lines */
 103         int beg_line_orig;      /* copy of the above, needed for -i */
 104         int end_line;           /* 'sed 1,3p' 0 == one line only. -1 = last line ($) */
 105
 106         FILE *sw_file;          /* File (sw) command writes to, -1 for none. */
 107         char *string;           /* Data string for (saicytb) commands. */
 108
 109         unsigned which_match;   /* (s) Which match to replace (0 for all) */
 110
 111         /* Bitfields (gcc won't group them if we don't) */
 112         unsigned invert:1;      /* the '!' after the address */
 113         unsigned in_match:1;    /* Next line also included in match? */
 114         unsigned sub_p:1;       /* (s) print option */
 115
 116         char sw_last_char;      /* Last line written by (sw) had no '\n' */
 117
 118         /* GENERAL FIELDS */
 119         char cmd;               /* The command char: abcdDgGhHilnNpPqrstwxy:={} */
 120 } sed_cmd_t;
 121
 122 static const char semicolon_whitespace[] ALIGN1 = "; \n\r\t\v";
 123
 124 struct globals {
 125         /* options */
 126         int be_quiet, regex_type;
 127         FILE *nonstdout;
 128         char *outname, *hold_space;
 129
 130         /* List of input files */
 131         int input_file_count, current_input_file;
 132         FILE **input_file_list;
 133
 134         regmatch_t regmatch[10];
 135         regex_t *previous_regex_ptr;
 136
 137         /* linked list of sed commands */
 138         sed_cmd_t *sed_cmd_head, **sed_cmd_tail;
 139
 140         /* Linked list of append lines */
 141         llist_t *append_head;
 142
 143         char *add_cmd_line;
 144
 145         struct pipeline {
 146                 char *buf;  /* Space to hold string */
 147                 int idx;    /* Space used */
 148                 int len;    /* Space allocated */
 149         } pipeline;
 150 } FIX_ALIASING;
 151 #define G (*(struct globals*)&bb_common_bufsiz1)
 152 struct BUG_G_too_big {
 153         char BUG_G_too_big[sizeof(G) <= COMMON_BUFSIZE ? 1 : -1];
 154 };
 155 #define INIT_G() do { \
 156         G.sed_cmd_tail = &G.sed_cmd_head; \
 157 } while (0)
 158
 159
 160 #if ENABLE_FEATURE_CLEAN_UP
 161 static void sed_free_and_close_stuff(void)
 162 {
 163         sed_cmd_t *sed_cmd = G.sed_cmd_head;
 164
 165         llist_free(G.append_head, free);
 166
 167         while (sed_cmd) {
 168                 sed_cmd_t *sed_cmd_next = sed_cmd->next;
 169
 170                 if (sed_cmd->sw_file)
 171                         xprint_and_close_file(sed_cmd->sw_file);
 172
 173                 if (sed_cmd->beg_match) {
 174                         regfree(sed_cmd->beg_match);
 175                         free(sed_cmd->beg_match);
 176                 }
 177                 if (sed_cmd->end_match) {
 178                         regfree(sed_cmd->end_match);
 179                         free(sed_cmd->end_match);
 180                 }
 181                 if (sed_cmd->sub_match) {
 182                         regfree(sed_cmd->sub_match);
 183                         free(sed_cmd->sub_match);
 184                 }
 185                 free(sed_cmd->string);
 186                 free(sed_cmd);
 187                 sed_cmd = sed_cmd_next;
 188         }
 189
 190         free(G.hold_space);
 191
 192         while (G.current_input_file < G.input_file_count)
 193                 fclose(G.input_file_list[G.current_input_file++]);
 194 }
 195 #else
 196 void sed_free_and_close_stuff(void);
 197 #endif
 198
 199 /* If something bad happens during -i operation, delete temp file */
 200
 201 static void cleanup_outname(void)
 202 {
 203         if (G.outname) unlink(G.outname);
 204 }
 205
 206 /* strcpy, replacing "\from" with 'to'. If to is NUL, replacing "\any" with 'any' */
 207
 208 static void parse_escapes(char *dest, const char *string, int len, char from, char to)
 209 {
 210         int i = 0;
 211
 212         while (i < len) {
 213                 if (string[i] == '\\') {
 214                         if (!to || string[i+1] == from) {
 215                                 *dest++ = to ? to : string[i+1];
 216                                 i += 2;
 217                                 continue;
 218                         }
 219                         *dest++ = string[i++];
 220                 }
 221                 /* TODO: is it safe wrt a string with trailing '\\' ? */
 222                 *dest++ = string[i++];
 223         }
 224         *dest = '\0';
 225 }
 226
 227 static char *copy_parsing_escapes(const char *string, int len)
 228 {
 229         const char *s;
 230         char *dest = xmalloc(len + 1);
 231
 232         /* sed recognizes \n */
 233         /* GNU sed also recognizes \t and \r */
 234         for (s = "\nn\tt\rr"; *s; s += 2) {
 235                 parse_escapes(dest, string, len, s[1], s[0]);
 236                 string = dest;
 237                 len = strlen(dest);
 238         }
 239         return dest;
 240 }
 241
 242
 243 /*
 244  * index_of_next_unescaped_regexp_delim - walks left to right through a string
 245  * beginning at a specified index and returns the index of the next regular
 246  * expression delimiter (typically a forward slash ('/')) not preceded by
 247  * a backslash ('\').  A negative delimiter disables square bracket checking.
 248  */
 249 static int index_of_next_unescaped_regexp_delim(int delimiter, const char *str)
 250 {
 251         int bracket = -1;
 252         int escaped = 0;
 253         int idx = 0;
 254         char ch;
 255
 256         if (delimiter < 0) {
 257                 bracket--;
 258                 delimiter = -delimiter;
 259         }
 260
 261         for (; (ch = str[idx]) != '\0'; idx++) {
 262                 if (bracket >= 0) {
 263                         if (ch == ']'
 264                          && !(bracket == idx - 1 || (bracket == idx - 2 && str[idx - 1] == '^'))
 265                         ) {
 266                                 bracket = -1;
 267                         }
 268                 } else if (escaped)
 269                         escaped = 0;
 270                 else if (ch == '\\')
 271                         escaped = 1;
 272                 else if (bracket == -1 && ch == '[')
 273                         bracket = idx;
 274                 else if (ch == delimiter)
 275                         return idx;
 276         }
 277
 278         /* if we make it to here, we've hit the end of the string */
 279         bb_error_msg_and_die("unmatched '%c'", delimiter);
 280 }
 281
 282 /*
 283  *  Returns the index of the third delimiter
 284  */
 285 static int parse_regex_delim(const char *cmdstr, char **match, char **replace)
 286 {
 287         const char *cmdstr_ptr = cmdstr;
 288         unsigned char delimiter;
 289         int idx = 0;
 290
 291         /* verify that the 's' or 'y' is followed by something.  That something
 292          * (typically a 'slash') is now our regexp delimiter... */
 293         if (*cmdstr == '\0')
 294                 bb_error_msg_and_die("bad format in substitution expression");
 295         delimiter = *cmdstr_ptr++;
 296
 297         /* save the match string */
 298         idx = index_of_next_unescaped_regexp_delim(delimiter, cmdstr_ptr);
 299         *match = copy_parsing_escapes(cmdstr_ptr, idx);
 300
 301         /* save the replacement string */
 302         cmdstr_ptr += idx + 1;
 303         idx = index_of_next_unescaped_regexp_delim(- (int)delimiter, cmdstr_ptr);
 304         *replace = copy_parsing_escapes(cmdstr_ptr, idx);
 305
 306         return ((cmdstr_ptr - cmdstr) + idx);
 307 }
 308
 309 /*
 310  * returns the index in the string just past where the address ends.
 311  */
 312 static int get_address(const char *my_str, int *linenum, regex_t ** regex)
 313 {
 314         const char *pos = my_str;
 315
 316         if (isdigit(*my_str)) {
 317                 *linenum = strtol(my_str, (char**)&pos, 10);
 318                 /* endstr shouldnt ever equal NULL */
 319         } else if (*my_str == '$') {
 320                 *linenum = -1;
 321                 pos++;
 322         } else if (*my_str == '/' || *my_str == '\\') {
 323                 int next;
 324                 char delimiter;
 325                 char *temp;
 326
 327                 delimiter = '/';
 328                 if (*my_str == '\\')
 329                         delimiter = *++pos;
 330                 next = index_of_next_unescaped_regexp_delim(delimiter, ++pos);
 331                 temp = copy_parsing_escapes(pos, next);
 332                 *regex = xzalloc(sizeof(regex_t));
 333                 xregcomp(*regex, temp, G.regex_type|REG_NEWLINE);
 334                 free(temp);
 335                 /* Move position to next character after last delimiter */
 336                 pos += (next+1);
 337         }
 338         return pos - my_str;
 339 }
 340
 341 /* Grab a filename.  Whitespace at start is skipped, then goes to EOL. */
 342 static int parse_file_cmd(/*sed_cmd_t *sed_cmd,*/ const char *filecmdstr, char **retval)
 343 {
 344         int start = 0, idx, hack = 0;
 345
 346         /* Skip whitespace, then grab filename to end of line */
 347         while (isspace(filecmdstr[start]))
 348                 start++;
 349         idx = start;
 350         while (filecmdstr[idx] && filecmdstr[idx] != '\n')
 351                 idx++;
 352
 353         /* If lines glued together, put backslash back. */
 354         if (filecmdstr[idx] == '\n')
 355                 hack = 1;
 356         if (idx == start)
 357                 bb_error_msg_and_die("empty filename");
 358         *retval = xstrndup(filecmdstr+start, idx-start+hack+1);
 359         if (hack)
 360                 (*retval)[idx] = '\\';
 361
 362         return idx;
 363 }
 364
 365 static int parse_subst_cmd(sed_cmd_t *sed_cmd, const char *substr)
 366 {
 367         int cflags = G.regex_type;
 368         char *match;
 369         int idx;
 370
 371         /*
 372          * A substitution command should look something like this:
 373          *    s/match/replace/ #gIpw
 374          *    ||     |        |||
 375          *    mandatory       optional
 376          */
 377         idx = parse_regex_delim(substr, &match, &sed_cmd->string);
 378
 379         /* determine the number of back references in the match string */
 380         /* Note: we compute this here rather than in the do_subst_command()
 381          * function to save processor time, at the expense of a little more memory
 382          * (4 bits) per sed_cmd */
 383
 384         /* process the flags */
 385
 386         sed_cmd->which_match = 1;
 387         while (substr[++idx]) {
 388                 /* Parse match number */
 389                 if (isdigit(substr[idx])) {
 390                         if (match[0] != '^') {
 391                                 /* Match 0 treated as all, multiple matches we take the last one. */
 392                                 const char *pos = substr + idx;
 393 /* FIXME: error check? */
 394                                 sed_cmd->which_match = (unsigned)strtol(substr+idx, (char**) &pos, 10);
 395                                 idx = pos - substr;
 396                         }
 397                         continue;
 398                 }
 399                 /* Skip spaces */
 400                 if (isspace(substr[idx]))
 401                         continue;
 402
 403                 switch (substr[idx]) {
 404                 /* Replace all occurrences */
 405                 case 'g':
 406                         if (match[0] != '^')
 407                                 sed_cmd->which_match = 0;
 408                         break;
 409                 /* Print pattern space */
 410                 case 'p':
 411                         sed_cmd->sub_p = 1;
 412                         break;
 413                 /* Write to file */
 414                 case 'w':
 415                 {
 416                         char *temp;
 417                         idx += parse_file_cmd(/*sed_cmd,*/ substr+idx, &temp);
 418                         break;
 419                 }
 420                 /* Ignore case (gnu exension) */
 421                 case 'I':
 422                         cflags |= REG_ICASE;
 423                         break;
 424                 /* Comment */
 425                 case '#':
 426                         // while (substr[++idx]) continue;
 427                         idx += strlen(substr + idx); // same
 428                         /* Fall through */
 429                 /* End of command */
 430                 case ';':
 431                 case '}':
 432                         goto out;
 433                 default:
 434                         bb_error_msg_and_die("bad option in substitution expression");
 435                 }
 436         }
 437  out:
 438         /* compile the match string into a regex */
 439         if (*match != '\0') {
 440                 /* If match is empty, we use last regex used at runtime */
 441                 sed_cmd->sub_match = xzalloc(sizeof(regex_t));
 442                 dbg("xregcomp('%s',%x)", match, cflags);
 443                 xregcomp(sed_cmd->sub_match, match, cflags);
 444                 dbg("regcomp ok");
 445         }
 446         free(match);
 447
 448         return idx;
 449 }
 450
 451 /*
 452  *  Process the commands arguments
 453  */
 454 static const char *parse_cmd_args(sed_cmd_t *sed_cmd, const char *cmdstr)
 455 {
 456         static const char cmd_letters[] = "saicrw:btTydDgGhHlnNpPqx={}";
 457         enum {
 458                 IDX_s = 0,
 459                 IDX_a,
 460                 IDX_i,
 461                 IDX_c,
 462                 IDX_r,
 463                 IDX_w,
 464                 IDX_colon,
 465                 IDX_b,
 466                 IDX_t,
 467                 IDX_T,
 468                 IDX_y,
 469                 IDX_d,
 470                 IDX_D,
 471                 IDX_g,
 472                 IDX_G,
 473                 IDX_h,
 474                 IDX_H,
 475                 IDX_l,
 476                 IDX_n,
 477                 IDX_N,
 478                 IDX_p,
 479                 IDX_P,
 480                 IDX_q,
 481                 IDX_x,
 482                 IDX_equal,
 483                 IDX_lbrace,
 484                 IDX_rbrace,
 485                 IDX_nul
 486         };
 487         struct chk { char chk[sizeof(cmd_letters)-1 == IDX_nul ? 1 : -1]; };
 488
 489         unsigned idx = strchrnul(cmd_letters, sed_cmd->cmd) - cmd_letters;
 490
 491         /* handle (s)ubstitution command */
 492         if (idx == IDX_s) {
 493                 cmdstr += parse_subst_cmd(sed_cmd, cmdstr);
 494         }
 495         /* handle edit cmds: (a)ppend, (i)nsert, and (c)hange */
 496         else if (idx <= IDX_c) { /* a,i,c */
 497                 if (idx < IDX_c) { /* a,i */
 498                         if (sed_cmd->end_line || sed_cmd->end_match)
 499                                 bb_error_msg_and_die("command '%c' uses only one address", sed_cmd->cmd);
 500                 }
 501                 for (;;) {
 502                         if (*cmdstr == '\n' || *cmdstr == '\\') {
 503                                 cmdstr++;
 504                                 break;
 505                         }
 506                         if (!isspace(*cmdstr))
 507                                 break;
 508                         cmdstr++;
 509                 }
 510                 sed_cmd->string = xstrdup(cmdstr);
 511                 /* "\anychar" -> "anychar" */
 512                 parse_escapes(sed_cmd->string, sed_cmd->string, strlen(cmdstr), '\0', '\0');
 513                 cmdstr += strlen(cmdstr);
 514         }
 515         /* handle file cmds: (r)ead */
 516         else if (idx <= IDX_w) { /* r,w */
 517                 if (idx < IDX_w) { /* r */
 518                         if (sed_cmd->end_line || sed_cmd->end_match)
 519                                 bb_error_msg_and_die("command '%c' uses only one address", sed_cmd->cmd);
 520                 }
 521                 cmdstr += parse_file_cmd(/*sed_cmd,*/ cmdstr, &sed_cmd->string);
 522                 if (sed_cmd->cmd == 'w') {
 523                         sed_cmd->sw_file = xfopen_for_write(sed_cmd->string);
 524                         sed_cmd->sw_last_char = '\n';
 525                 }
 526         }
 527         /* handle branch commands */
 528         else if (idx <= IDX_T) { /* :,b,t,T */
 529                 int length;
 530
 531                 cmdstr = skip_whitespace(cmdstr);
 532                 length = strcspn(cmdstr, semicolon_whitespace);
 533                 if (length) {
 534                         sed_cmd->string = xstrndup(cmdstr, length);
 535                         cmdstr += length;
 536                 }
 537         }
 538         /* translation command */
 539         else if (idx == IDX_y) {
 540                 char *match, *replace;
 541                 int i = cmdstr[0];
 542
 543                 cmdstr += parse_regex_delim(cmdstr, &match, &replace)+1;
 544                 /* \n already parsed, but \delimiter needs unescaping. */
 545                 parse_escapes(match, match, strlen(match), i, i);
 546                 parse_escapes(replace, replace, strlen(replace), i, i);
 547
 548                 sed_cmd->string = xzalloc((strlen(match) + 1) * 2);
 549                 for (i = 0; match[i] && replace[i]; i++) {
 550                         sed_cmd->string[i*2] = match[i];
 551                         sed_cmd->string[i*2+1] = replace[i];
 552                 }
 553                 free(match);
 554                 free(replace);
 555         }
 556         /* if it wasnt a single-letter command that takes no arguments
 557          * then it must be an invalid command.
 558          */
 559         else if (idx >= IDX_nul) { /* not d,D,g,G,h,H,l,n,N,p,P,q,x,=,{,} */
 560                 bb_error_msg_and_die("unsupported command %c", sed_cmd->cmd);
 561         }
 562
 563         /* give back whatever's left over */
 564         return cmdstr;
 565 }
 566
 567
 568 /* Parse address+command sets, skipping comment lines. */
 569
 570 static void add_cmd(const char *cmdstr)
 571 {
 572         sed_cmd_t *sed_cmd;
 573         unsigned len, n;
 574
 575         /* Append this line to any unfinished line from last time. */
 576         if (G.add_cmd_line) {
 577                 char *tp = xasprintf("%s\n%s", G.add_cmd_line, cmdstr);
 578                 free(G.add_cmd_line);
 579                 cmdstr = G.add_cmd_line = tp;
 580         }
 581
 582         /* If this line ends with unescaped backslash, request next line. */
 583         n = len = strlen(cmdstr);
 584         while (n && cmdstr[n-1] == '\\')
 585                 n--;
 586         if ((len - n) & 1) { /* if odd number of trailing backslashes */
 587                 if (!G.add_cmd_line)
 588                         G.add_cmd_line = xstrdup(cmdstr);
 589                 G.add_cmd_line[len-1] = '\0';
 590                 return;
 591         }
 592
 593         /* Loop parsing all commands in this line. */
 594         while (*cmdstr) {
 595                 /* Skip leading whitespace and semicolons */
 596                 cmdstr += strspn(cmdstr, semicolon_whitespace);
 597
 598                 /* If no more commands, exit. */
 599                 if (!*cmdstr) break;
 600
 601                 /* if this is a comment, jump past it and keep going */
 602                 if (*cmdstr == '#') {
 603                         /* "#n" is the same as using -n on the command line */
 604                         if (cmdstr[1] == 'n')
 605                                 G.be_quiet++;
 606                         cmdstr = strpbrk(cmdstr, "\n\r");
 607                         if (!cmdstr) break;
 608                         continue;
 609                 }
 610
 611                 /* parse the command
 612                  * format is: [addr][,addr][!]cmd
 613                  *            |----||-----||-|
 614                  *            part1 part2  part3
 615                  */
 616
 617                 sed_cmd = xzalloc(sizeof(sed_cmd_t));
 618
 619                 /* first part (if present) is an address: either a '$', a number or a /regex/ */
 620                 cmdstr += get_address(cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
 621                 sed_cmd->beg_line_orig = sed_cmd->beg_line;
 622
 623                 /* second part (if present) will begin with a comma */
 624                 if (*cmdstr == ',') {
 625                         int idx;
 626
 627                         cmdstr++;
 628                         idx = get_address(cmdstr, &sed_cmd->end_line, &sed_cmd->end_match);
 629                         if (!idx)
 630                                 bb_error_msg_and_die("no address after comma");
 631                         cmdstr += idx;
 632                 }
 633
 634                 /* skip whitespace before the command */
 635                 cmdstr = skip_whitespace(cmdstr);
 636
 637                 /* Check for inversion flag */
 638                 if (*cmdstr == '!') {
 639                         sed_cmd->invert = 1;
 640                         cmdstr++;
 641
 642                         /* skip whitespace before the command */
 643                         cmdstr = skip_whitespace(cmdstr);
 644                 }
 645
 646                 /* last part (mandatory) will be a command */
 647                 if (!*cmdstr)
 648                         bb_error_msg_and_die("missing command");
 649                 sed_cmd->cmd = *cmdstr++;
 650                 cmdstr = parse_cmd_args(sed_cmd, cmdstr);
 651
 652                 /* Add the command to the command array */
 653                 *G.sed_cmd_tail = sed_cmd;
 654                 G.sed_cmd_tail = &sed_cmd->next;
 655         }
 656
 657         /* If we glued multiple lines together, free the memory. */
 658         free(G.add_cmd_line);
 659         G.add_cmd_line = NULL;
 660 }
 661
 662 /* Append to a string, reallocating memory as necessary. */
 663
 664 #define PIPE_GROW 64
 665
 666 static void pipe_putc(char c)
 667 {
 668         if (G.pipeline.idx == G.pipeline.len) {
 669                 G.pipeline.buf = xrealloc(G.pipeline.buf,
 670                                 G.pipeline.len + PIPE_GROW);
 671                 G.pipeline.len += PIPE_GROW;
 672         }
 673         G.pipeline.buf[G.pipeline.idx++] = c;
 674 }
 675
 676 static void do_subst_w_backrefs(char *line, char *replace)
 677 {
 678         int i, j;
 679
 680         /* go through the replacement string */
 681         for (i = 0; replace[i]; i++) {
 682                 /* if we find a backreference (\1, \2, etc.) print the backref'ed text */
 683                 if (replace[i] == '\\') {
 684                         unsigned backref = replace[++i] - '0';
 685                         if (backref <= 9) {
 686                                 /* print out the text held in G.regmatch[backref] */
 687                                 if (G.regmatch[backref].rm_so != -1) {
 688                                         j = G.regmatch[backref].rm_so;
 689                                         while (j < G.regmatch[backref].rm_eo)
 690                                                 pipe_putc(line[j++]);
 691                                 }
 692                                 continue;
 693                         }
 694                         /* I _think_ it is impossible to get '\' to be
 695                          * the last char in replace string. Thus we dont check
 696                          * for replace[i] == NUL. (counterexample anyone?) */
 697                         /* if we find a backslash escaped character, print the character */
 698                         pipe_putc(replace[i]);
 699                         continue;
 700                 }
 701                 /* if we find an unescaped '&' print out the whole matched text. */
 702                 if (replace[i] == '&') {
 703                         j = G.regmatch[0].rm_so;
 704                         while (j < G.regmatch[0].rm_eo)
 705                                 pipe_putc(line[j++]);
 706                         continue;
 707                 }
 708                 /* Otherwise just output the character. */
 709                 pipe_putc(replace[i]);
 710         }
 711 }
 712
 713 static int do_subst_command(sed_cmd_t *sed_cmd, char **line_p)
 714 {
 715         char *line = *line_p;
 716         unsigned match_count = 0;
 717         bool altered = 0;
 718         bool prev_match_empty = 1;
 719         bool tried_at_eol = 0;
 720         regex_t *current_regex;
 721
 722         current_regex = sed_cmd->sub_match;
 723         /* Handle empty regex. */
 724         if (!current_regex) {
 725                 current_regex = G.previous_regex_ptr;
 726                 if (!current_regex)
 727                         bb_error_msg_and_die("no previous regexp");
 728         }
 729         G.previous_regex_ptr = current_regex;
 730
 731         /* Find the first match */
 732         dbg("matching '%s'", line);
 733         if (REG_NOMATCH == regexec(current_regex, line, 10, G.regmatch, 0)) {
 734                 dbg("no match");
 735                 return 0;
 736         }
 737         dbg("match");
 738
 739         /* Initialize temporary output buffer. */
 740         G.pipeline.buf = xmalloc(PIPE_GROW);
 741         G.pipeline.len = PIPE_GROW;
 742         G.pipeline.idx = 0;
 743
 744         /* Now loop through, substituting for matches */
 745         do {
 746                 int start = G.regmatch[0].rm_so;
 747                 int end = G.regmatch[0].rm_eo;
 748                 int i;
 749
 750                 match_count++;
 751
 752                 /* If we aren't interested in this match, output old line to
 753                  * end of match and continue */
 754                 if (sed_cmd->which_match
 755                  && (sed_cmd->which_match != match_count)
 756                 ) {
 757                         for (i = 0; i < end; i++)
 758                                 pipe_putc(*line++);
 759                         /* Null match? Print one more char */
 760                         if (start == end && *line)
 761                                 pipe_putc(*line++);
 762                         goto next;
 763                 }
 764
 765                 /* Print everything before the match */
 766                 for (i = 0; i < start; i++)
 767                         pipe_putc(line[i]);
 768
 769                 /* Then print the substitution string,
 770                  * unless we just matched empty string after non-empty one.
 771                  * Example: string "cccd", pattern "c*", repl "R":
 772                  * result is "RdR", not "RRdR": first match "ccc",
 773                  * second is "" before "d", third is "" after "d".
 774                  * Second match is NOT replaced!
 775                  */
 776                 if (prev_match_empty || start != 0 || start != end) {
 777                         //dbg("%d %d %d", prev_match_empty, start, end);
 778                         dbg("inserting replacement at %d in '%s'", start, line);
 779                         do_subst_w_backrefs(line, sed_cmd->string);
 780                         /* Flag that something has changed */
 781                         altered = 1;
 782                 } else {
 783                         dbg("NOT inserting replacement at %d in '%s'", start, line);
 784                 }
 785
 786                 /* If matched string is empty (f.e. "c*" pattern),
 787                  * copy verbatim one char after it before attempting more matches
 788                  */
 789                 prev_match_empty = (start == end);
 790                 if (prev_match_empty) {
 791                         if (!line[end]) {
 792                                 tried_at_eol = 1;
 793                         } else {
 794                                 pipe_putc(line[end]);
 795                                 end++;
 796                         }
 797                 }
 798
 799                 /* Advance past the match */
 800                 dbg("line += %d", end);
 801                 line += end;
 802
 803                 /* if we're not doing this globally, get out now */
 804                 if (sed_cmd->which_match != 0)
 805                         break;
 806  next:
 807                 /* Exit if we are at EOL and already tried matching at it */
 808                 if (*line == '\0') {
 809                         if (tried_at_eol)
 810                                 break;
 811                         tried_at_eol = 1;
 812                 }
 813
 814 //maybe (end ? REG_NOTBOL : 0) instead of unconditional REG_NOTBOL?
 815         } while (regexec(current_regex, line, 10, G.regmatch, REG_NOTBOL) != REG_NOMATCH);
 816
 817         /* Copy rest of string into output pipeline */
 818         while (1) {
 819                 char c = *line++;
 820                 pipe_putc(c);
 821                 if (c == '\0')
 822                         break;
 823         }
 824
 825         free(*line_p);
 826         *line_p = G.pipeline.buf;
 827         return altered;
 828 }
 829
 830 /* Set command pointer to point to this label.  (Does not handle null label.) */
 831 static sed_cmd_t *branch_to(char *label)
 832 {
 833         sed_cmd_t *sed_cmd;
 834
 835         for (sed_cmd = G.sed_cmd_head; sed_cmd; sed_cmd = sed_cmd->next) {
 836                 if (sed_cmd->cmd == ':' && sed_cmd->string && !strcmp(sed_cmd->string, label)) {
 837                         return sed_cmd;
 838                 }
 839         }
 840         bb_error_msg_and_die("can't find label for jump to '%s'", label);
 841 }
 842
 843 static void append(char *s)
 844 {
 845         llist_add_to_end(&G.append_head, xstrdup(s));
 846 }
 847
 848 static void flush_append(void)
 849 {
 850         char *data;
 851
 852         /* Output appended lines. */
 853         while ((data = (char *)llist_pop(&G.append_head))) {
 854                 fprintf(G.nonstdout, "%s\n", data);
 855                 free(data);
 856         }
 857 }
 858
 859 static void add_input_file(FILE *file)
 860 {
 861         G.input_file_list = xrealloc_vector(G.input_file_list, 2, G.input_file_count);
 862         G.input_file_list[G.input_file_count++] = file;
 863 }
 864
 865 /* Get next line of input from G.input_file_list, flushing append buffer and
 866  * noting if we ran out of files without a newline on the last line we read.
 867  */
 868 enum {
 869         NO_EOL_CHAR = 1,
 870         LAST_IS_NUL = 2,
 871 };
 872 static char *get_next_line(char *gets_char)
 873 {
 874         char *temp = NULL;
 875         int len;
 876         char gc;
 877
 878         flush_append();
 879
 880         /* will be returned if last line in the file
 881          * doesn't end with either '\n' or '\0' */
 882         gc = NO_EOL_CHAR;
 883         while (G.current_input_file < G.input_file_count) {
 884                 FILE *fp = G.input_file_list[G.current_input_file];
 885                 /* Read line up to a newline or NUL byte, inclusive,
 886                  * return malloc'ed char[]. length of the chunk read
 887                  * is stored in len. NULL if EOF/error */
 888                 temp = bb_get_chunk_from_file(fp, &len);
 889                 if (temp) {
 890                         /* len > 0 here, it's ok to do temp[len-1] */
 891                         char c = temp[len-1];
 892                         if (c == '\n' || c == '\0') {
 893                                 temp[len-1] = '\0';
 894                                 gc = c;
 895                                 if (c == '\0') {
 896                                         int ch = fgetc(fp);
 897                                         if (ch != EOF)
 898                                                 ungetc(ch, fp);
 899                                         else
 900                                                 gc = LAST_IS_NUL;
 901                                 }
 902                         }
 903                         /* else we put NO_EOL_CHAR into *gets_char */
 904                         break;
 905
 906                 /* NB: I had the idea of peeking next file(s) and returning
 907                  * NO_EOL_CHAR only if it is the *last* non-empty
 908                  * input file. But there is a case where this won't work:
 909                  * file1: "a woo\nb woo"
 910                  * file2: "c no\nd no"
 911                  * sed -ne 's/woo/bang/p' input1 input2 => "a bang\nb bang"
 912                  * (note: *no* newline after "b bang"!) */
 913                 }
 914                 /* Close this file and advance to next one */
 915                 fclose(fp);
 916                 G.current_input_file++;
 917         }
 918         *gets_char = gc;
 919         return temp;
 920 }
 921
 922 /* Output line of text. */
 923 /* Note:
 924  * The tricks with NO_EOL_CHAR and last_puts_char are there to emulate gnu sed.
 925  * Without them, we had this:
 926  * echo -n thingy >z1
 927  * echo -n again >z2
 928  * >znull
 929  * sed "s/i/z/" z1 z2 znull | hexdump -vC
 930  * output:
 931  * gnu sed 4.1.5:
 932  * 00000000  74 68 7a 6e 67 79 0a 61  67 61 7a 6e              |thzngy.agazn|
 933  * bbox:
 934  * 00000000  74 68 7a 6e 67 79 61 67  61 7a 6e                 |thzngyagazn|
 935  */
 936 static void puts_maybe_newline(char *s, FILE *file, char *last_puts_char, char last_gets_char)
 937 {
 938         char lpc = *last_puts_char;
 939
 940         /* Need to insert a '\n' between two files because first file's
 941          * last line wasn't terminated? */
 942         if (lpc != '\n' && lpc != '\0') {
 943                 fputc('\n', file);
 944                 lpc = '\n';
 945         }
 946         fputs(s, file);
 947
 948         /* 'x' - just something which is not '\n', '\0' or NO_EOL_CHAR */
 949         if (s[0])
 950                 lpc = 'x';
 951
 952         /* had trailing '\0' and it was last char of file? */
 953         if (last_gets_char == LAST_IS_NUL) {
 954                 fputc('\0', file);
 955                 lpc = 'x'; /* */
 956         } else
 957         /* had trailing '\n' or '\0'? */
 958         if (last_gets_char != NO_EOL_CHAR) {
 959                 fputc(last_gets_char, file);
 960                 lpc = last_gets_char;
 961         }
 962
 963         if (ferror(file)) {
 964                 xfunc_error_retval = 4;  /* It's what gnu sed exits with... */
 965                 bb_error_msg_and_die(bb_msg_write_error);
 966         }
 967         *last_puts_char = lpc;
 968 }
 969
 970 #define sed_puts(s, n) (puts_maybe_newline(s, G.nonstdout, &last_puts_char, n))
 971
 972 static int beg_match(sed_cmd_t *sed_cmd, const char *pattern_space)
 973 {
 974         int retval = sed_cmd->beg_match && !regexec(sed_cmd->beg_match, pattern_space, 0, NULL, 0);
 975         if (retval)
 976                 G.previous_regex_ptr = sed_cmd->beg_match;
 977         return retval;
 978 }
 979
 980 /* Process all the lines in all the files */
 981
 982 static void process_files(void)
 983 {
 984         char *pattern_space, *next_line;
 985         int linenum = 0;
 986         char last_puts_char = '\n';
 987         char last_gets_char, next_gets_char;
 988         sed_cmd_t *sed_cmd;
 989         int substituted;
 990
 991         /* Prime the pump */
 992         next_line = get_next_line(&next_gets_char);
 993
 994         /* Go through every line in each file */
 995  again:
 996         substituted = 0;
 997
 998         /* Advance to next line.  Stop if out of lines. */
 999         pattern_space = next_line;
1000         if (!pattern_space)
1001                 return;
1002         last_gets_char = next_gets_char;
1003
1004         /* Read one line in advance so we can act on the last line,
1005          * the '$' address */
1006         next_line = get_next_line(&next_gets_char);
1007         linenum++;
1008
1009         /* For every line, go through all the commands */
1010  restart:
1011         for (sed_cmd = G.sed_cmd_head; sed_cmd; sed_cmd = sed_cmd->next) {
1012                 int old_matched, matched;
1013
1014                 old_matched = sed_cmd->in_match;
1015
1016                 /* Determine if this command matches this line: */
1017
1018                 dbg("match1:%d", sed_cmd->in_match);
1019                 dbg("match2:%d", (!sed_cmd->beg_line && !sed_cmd->end_line
1020                                 && !sed_cmd->beg_match && !sed_cmd->end_match));
1021                 dbg("match3:%d", (sed_cmd->beg_line > 0
1022                         && (sed_cmd->end_line || sed_cmd->end_match
1023                             ? (sed_cmd->beg_line <= linenum)
1024                             : (sed_cmd->beg_line == linenum)
1025                             )
1026                         ));
1027                 dbg("match4:%d", (beg_match(sed_cmd, pattern_space)));
1028                 dbg("match5:%d", (sed_cmd->beg_line == -1 && next_line == NULL));
1029
1030                 /* Are we continuing a previous multi-line match? */
1031                 sed_cmd->in_match = sed_cmd->in_match
1032                         /* Or is no range necessary? */
1033                         || (!sed_cmd->beg_line && !sed_cmd->end_line
1034                                 && !sed_cmd->beg_match && !sed_cmd->end_match)
1035                         /* Or did we match the start of a numerical range? */
1036                         || (sed_cmd->beg_line > 0
1037                             && (sed_cmd->end_line || sed_cmd->end_match
1038                                   /* note: even if end is numeric and is < linenum too,
1039                                    * GNU sed matches! We match too, therefore we don't
1040                                    * check here that linenum <= end.
1041                                    * Example:
1042                                    * printf '1\n2\n3\n4\n' | sed -n '1{N;N;d};1p;2,3p;3p;4p'
1043                                    * first three input lines are deleted;
1044                                    * 4th line is matched and printed
1045                                    * by "2,3" (!) and by "4" ranges
1046                                    */
1047                                 ? (sed_cmd->beg_line <= linenum)    /* N,end */
1048                                 : (sed_cmd->beg_line == linenum)    /* N */
1049                                 )
1050                             )
1051                         /* Or does this line match our begin address regex? */
1052                         || (beg_match(sed_cmd, pattern_space))
1053                         /* Or did we match last line of input? */
1054                         || (sed_cmd->beg_line == -1 && next_line == NULL);
1055
1056                 /* Snapshot the value */
1057                 matched = sed_cmd->in_match;
1058
1059                 dbg("cmd:'%c' matched:%d beg_line:%d end_line:%d linenum:%d",
1060                         sed_cmd->cmd, matched, sed_cmd->beg_line, sed_cmd->end_line, linenum);
1061
1062                 /* Is this line the end of the current match? */
1063
1064                 if (matched) {
1065                         /* once matched, "n,xxx" range is dead, disabling it */
1066                         if (sed_cmd->beg_line > 0) {
1067                                 sed_cmd->beg_line = -2;
1068                         }
1069                         sed_cmd->in_match = !(
1070                                 /* has the ending line come, or is this a single address command? */
1071                                 (sed_cmd->end_line
1072                                         ? sed_cmd->end_line == -1
1073                                                 ? !next_line
1074                                                 : (sed_cmd->end_line <= linenum)
1075                                         : !sed_cmd->end_match
1076                                 )
1077                                 /* or does this line matches our last address regex */
1078                                 || (sed_cmd->end_match && old_matched
1079                                      && (regexec(sed_cmd->end_match,
1080                                                  pattern_space, 0, NULL, 0) == 0)
1081                                 )
1082                         );
1083                 }
1084
1085                 /* Skip blocks of commands we didn't match */
1086                 if (sed_cmd->cmd == '{') {
1087                         if (sed_cmd->invert ? matched : !matched) {
1088                                 unsigned nest_cnt = 0;
1089                                 while (1) {
1090                                         if (sed_cmd->cmd == '{')
1091                                                 nest_cnt++;
1092                                         if (sed_cmd->cmd == '}') {
1093                                                 nest_cnt--;
1094                                                 if (nest_cnt == 0)
1095                                                         break;
1096                                         }
1097                                         sed_cmd = sed_cmd->next;
1098                                         if (!sed_cmd)
1099                                                 bb_error_msg_and_die("unterminated {");
1100                                 }
1101                         }
1102                         continue;
1103                 }
1104
1105                 /* Okay, so did this line match? */
1106                 if (sed_cmd->invert ? matched : !matched)
1107                         continue; /* no */
1108
1109                 /* Update last used regex in case a blank substitute BRE is found */
1110                 if (sed_cmd->beg_match) {
1111                         G.previous_regex_ptr = sed_cmd->beg_match;
1112                 }
1113
1114                 /* actual sedding */
1115                 dbg("pattern_space:'%s' next_line:'%s' cmd:%c",
1116                                 pattern_space, next_line, sed_cmd->cmd);
1117                 switch (sed_cmd->cmd) {
1118
1119                 /* Print line number */
1120                 case '=':
1121                         fprintf(G.nonstdout, "%d\n", linenum);
1122                         break;
1123
1124                 /* Write the current pattern space up to the first newline */
1125                 case 'P':
1126                 {
1127                         char *tmp = strchr(pattern_space, '\n');
1128                         if (tmp) {
1129                                 *tmp = '\0';
1130                                 /* TODO: explain why '\n' below */
1131                                 sed_puts(pattern_space, '\n');
1132                                 *tmp = '\n';
1133                                 break;
1134                         }
1135                         /* Fall Through */
1136                 }
1137
1138                 /* Write the current pattern space to output */
1139                 case 'p':
1140                         /* NB: we print this _before_ the last line
1141                          * (of current file) is printed. Even if
1142                          * that line is nonterminated, we print
1143                          * '\n' here (gnu sed does the same) */
1144                         sed_puts(pattern_space, '\n');
1145                         break;
1146                 /* Delete up through first newline */
1147                 case 'D':
1148                 {
1149                         char *tmp = strchr(pattern_space, '\n');
1150                         if (tmp) {
1151                                 overlapping_strcpy(pattern_space, tmp + 1);
1152                                 goto restart;
1153                         }
1154                 }
1155                 /* discard this line. */
1156                 case 'd':
1157                         goto discard_line;
1158
1159                 /* Substitute with regex */
1160                 case 's':
1161                         if (!do_subst_command(sed_cmd, &pattern_space))
1162                                 break;
1163                         dbg("do_subst_command succeeded:'%s'", pattern_space);
1164                         substituted |= 1;
1165
1166                         /* handle p option */
1167                         if (sed_cmd->sub_p)
1168                                 sed_puts(pattern_space, last_gets_char);
1169                         /* handle w option */
1170                         if (sed_cmd->sw_file)
1171                                 puts_maybe_newline(
1172                                         pattern_space, sed_cmd->sw_file,
1173                                         &sed_cmd->sw_last_char, last_gets_char);
1174                         break;
1175
1176                 /* Append line to linked list to be printed later */
1177                 case 'a':
1178                         append(sed_cmd->string);
1179                         break;
1180
1181                 /* Insert text before this line */
1182                 case 'i':
1183                         sed_puts(sed_cmd->string, '\n');
1184                         break;
1185
1186                 /* Cut and paste text (replace) */
1187                 case 'c':
1188                         /* Only triggers on last line of a matching range. */
1189                         if (!sed_cmd->in_match)
1190                                 sed_puts(sed_cmd->string, '\n');
1191                         goto discard_line;
1192
1193                 /* Read file, append contents to output */
1194                 case 'r':
1195                 {
1196                         FILE *rfile;
1197                         rfile = fopen_for_read(sed_cmd->string);
1198                         if (rfile) {
1199                                 char *line;
1200
1201                                 while ((line = xmalloc_fgetline(rfile))
1202                                                 != NULL)
1203                                         append(line);
1204                                 xprint_and_close_file(rfile);
1205                         }
1206
1207                         break;
1208                 }
1209
1210                 /* Write pattern space to file. */
1211                 case 'w':
1212                         puts_maybe_newline(
1213                                 pattern_space, sed_cmd->sw_file,
1214                                 &sed_cmd->sw_last_char, last_gets_char);
1215                         break;
1216
1217                 /* Read next line from input */
1218                 case 'n':
1219                         if (!G.be_quiet)
1220                                 sed_puts(pattern_space, last_gets_char);
1221                         if (next_line) {
1222                                 free(pattern_space);
1223                                 pattern_space = next_line;
1224                                 last_gets_char = next_gets_char;
1225                                 next_line = get_next_line(&next_gets_char);
1226                                 substituted = 0;
1227                                 linenum++;
1228                                 break;
1229                         }
1230                         /* fall through */
1231
1232                 /* Quit.  End of script, end of input. */
1233                 case 'q':
1234                         /* Exit the outer while loop */
1235                         free(next_line);
1236                         next_line = NULL;
1237                         goto discard_commands;
1238
1239                 /* Append the next line to the current line */
1240                 case 'N':
1241                 {
1242                         int len;
1243                         /* If no next line, jump to end of script and exit. */
1244                         /* http://www.gnu.org/software/sed/manual/sed.html:
1245                          * "Most versions of sed exit without printing anything
1246                          * when the N command is issued on the last line of
1247                          * a file. GNU sed prints pattern space before exiting
1248                          * unless of course the -n command switch has been
1249                          * specified. This choice is by design."
1250                          */
1251                         if (next_line == NULL) {
1252                                 //goto discard_line;
1253                                 goto discard_commands; /* GNU behavior */
1254                         }
1255                         /* Append next_line, read new next_line. */
1256                         len = strlen(pattern_space);
1257                         pattern_space = xrealloc(pattern_space, len + strlen(next_line) + 2);
1258                         pattern_space[len] = '\n';
1259                         strcpy(pattern_space + len+1, next_line);
1260                         last_gets_char = next_gets_char;
1261                         next_line = get_next_line(&next_gets_char);
1262                         linenum++;
1263                         break;
1264                 }
1265
1266                 /* Test/branch if substitution occurred */
1267                 case 't':
1268                         if (!substituted) break;
1269                         substituted = 0;
1270                         /* Fall through */
1271                 /* Test/branch if substitution didn't occur */
1272                 case 'T':
1273                         if (substituted) break;
1274                         /* Fall through */
1275                 /* Branch to label */
1276                 case 'b':
1277                         if (!sed_cmd->string) goto discard_commands;
1278                         else sed_cmd = branch_to(sed_cmd->string);
1279                         break;
1280                 /* Transliterate characters */
1281                 case 'y':
1282                 {
1283                         int i, j;
1284                         for (i = 0; pattern_space[i]; i++) {
1285                                 for (j = 0; sed_cmd->string[j]; j += 2) {
1286                                         if (pattern_space[i] == sed_cmd->string[j]) {
1287                                                 pattern_space[i] = sed_cmd->string[j + 1];
1288                                                 break;
1289                                         }
1290                                 }
1291                         }
1292
1293                         break;
1294                 }
1295                 case 'g':       /* Replace pattern space with hold space */
1296                         free(pattern_space);
1297                         pattern_space = xstrdup(G.hold_space ? G.hold_space : "");
1298                         break;
1299                 case 'G':       /* Append newline and hold space to pattern space */
1300                 {
1301                         int pattern_space_size = 2;
1302                         int hold_space_size = 0;
1303
1304                         if (pattern_space)
1305                                 pattern_space_size += strlen(pattern_space);
1306                         if (G.hold_space)
1307                                 hold_space_size = strlen(G.hold_space);
1308                         pattern_space = xrealloc(pattern_space,
1309                                         pattern_space_size + hold_space_size);
1310                         if (pattern_space_size == 2)
1311                                 pattern_space[0] = 0;
1312                         strcat(pattern_space, "\n");
1313                         if (G.hold_space)
1314                                 strcat(pattern_space, G.hold_space);
1315                         last_gets_char = '\n';
1316
1317                         break;
1318                 }
1319                 case 'h':       /* Replace hold space with pattern space */
1320                         free(G.hold_space);
1321                         G.hold_space = xstrdup(pattern_space);
1322                         break;
1323                 case 'H':       /* Append newline and pattern space to hold space */
1324                 {
1325                         int hold_space_size = 2;
1326                         int pattern_space_size = 0;
1327
1328                         if (G.hold_space)
1329                                 hold_space_size += strlen(G.hold_space);
1330                         if (pattern_space)
1331                                 pattern_space_size = strlen(pattern_space);
1332                         G.hold_space = xrealloc(G.hold_space,
1333                                         hold_space_size + pattern_space_size);
1334
1335                         if (hold_space_size == 2)
1336                                 *G.hold_space = 0;
1337                         strcat(G.hold_space, "\n");
1338                         if (pattern_space)
1339                                 strcat(G.hold_space, pattern_space);
1340
1341                         break;
1342                 }
1343                 case 'x': /* Exchange hold and pattern space */
1344                 {
1345                         char *tmp = pattern_space;
1346                         pattern_space = G.hold_space ? G.hold_space : xzalloc(1);
1347                         last_gets_char = '\n';
1348                         G.hold_space = tmp;
1349                         break;
1350                 }
1351                 } /* switch */
1352         } /* for each cmd */
1353
1354         /*
1355          * Exit point from sedding...
1356          */
1357  discard_commands:
1358         /* we will print the line unless we were told to be quiet ('-n')
1359            or if the line was suppressed (ala 'd'elete) */
1360         if (!G.be_quiet)
1361                 sed_puts(pattern_space, last_gets_char);
1362
1363         /* Delete and such jump here. */
1364  discard_line:
1365         flush_append();
1366         free(pattern_space);
1367
1368         goto again;
1369 }
1370
1371 /* It is possible to have a command line argument with embedded
1372  * newlines.  This counts as multiple command lines.
1373  * However, newline can be escaped: 's/e/z\<newline>z/'
1374  * We check for this.
1375  */
1376
1377 static void add_cmd_block(char *cmdstr)
1378 {
1379         char *sv, *eol;
1380
1381         cmdstr = sv = xstrdup(cmdstr);
1382         do {
1383                 eol = strchr(cmdstr, '\n');
1384  next:
1385                 if (eol) {
1386                         /* Count preceding slashes */
1387                         int slashes = 0;
1388                         char *sl = eol;
1389
1390                         while (sl != cmdstr && *--sl == '\\')
1391                                 slashes++;
1392                         /* Odd number of preceding slashes - newline is escaped */
1393                         if (slashes & 1) {
1394                                 overlapping_strcpy(eol - 1, eol);
1395                                 eol = strchr(eol, '\n');
1396                                 goto next;
1397                         }
1398                         *eol = '\0';
1399                 }
1400                 add_cmd(cmdstr);
1401                 cmdstr = eol + 1;
1402         } while (eol);
1403         free(sv);
1404 }
1405
1406 int sed_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1407 int sed_main(int argc UNUSED_PARAM, char **argv)
1408 {
1409         unsigned opt;
1410         llist_t *opt_e, *opt_f;
1411         char *opt_i;
1412
1413 #if ENABLE_LONG_OPTS
1414         static const char sed_longopts[] ALIGN1 =
1415                 /* name             has_arg             short */
1416                 "in-place\0"        Optional_argument   "i"
1417                 "regexp-extended\0" No_argument         "r"
1418                 "quiet\0"           No_argument         "n"
1419                 "silent\0"          No_argument         "n"
1420                 "expression\0"      Required_argument   "e"
1421                 "file\0"            Required_argument   "f";
1422 #endif
1423
1424         int status = EXIT_SUCCESS;
1425
1426         INIT_G();
1427
1428         /* destroy command strings on exit */
1429         if (ENABLE_FEATURE_CLEAN_UP) atexit(sed_free_and_close_stuff);
1430
1431         /* Lie to autoconf when it starts asking stupid questions. */
1432         if (argv[1] && strcmp(argv[1], "--version") == 0) {
1433                 puts("This is not GNU sed version 4.0");
1434                 return 0;
1435         }
1436
1437         /* do normal option parsing */
1438         opt_e = opt_f = NULL;
1439         opt_i = NULL;
1440         opt_complementary = "e::f::" /* can occur multiple times */
1441                             "nn"; /* count -n */
1442
1443         IF_LONG_OPTS(applet_long_options = sed_longopts);
1444
1445         /* -i must be first, to match OPT_in_place definition */
1446         opt = getopt32(argv, "i::rne:f:", &opt_i, &opt_e, &opt_f,
1447                             &G.be_quiet); /* counter for -n */
1448         //argc -= optind;
1449         argv += optind;
1450         if (opt & OPT_in_place) { // -i
1451                 atexit(cleanup_outname);
1452         }
1453         if (opt & 0x2) G.regex_type |= REG_EXTENDED; // -r
1454         //if (opt & 0x4) G.be_quiet++; // -n
1455         while (opt_e) { // -e
1456                 add_cmd_block(llist_pop(&opt_e));
1457         }
1458         while (opt_f) { // -f
1459                 char *line;
1460                 FILE *cmdfile;
1461                 cmdfile = xfopen_for_read(llist_pop(&opt_f));
1462                 while ((line = xmalloc_fgetline(cmdfile)) != NULL) {
1463                         add_cmd(line);
1464                         free(line);
1465                 }
1466                 fclose(cmdfile);
1467         }
1468         /* if we didn't get a pattern from -e or -f, use argv[0] */
1469         if (!(opt & 0x18)) {
1470                 if (!*argv)
1471                         bb_show_usage();
1472                 add_cmd_block(*argv++);
1473         }
1474         /* Flush any unfinished commands. */
1475         add_cmd("");
1476
1477         /* By default, we write to stdout */
1478         G.nonstdout = stdout;
1479
1480         /* argv[0..(argc-1)] should be names of file to process. If no
1481          * files were specified or '-' was specified, take input from stdin.
1482          * Otherwise, we process all the files specified. */
1483         if (argv[0] == NULL) {
1484                 if (opt & OPT_in_place)
1485                         bb_error_msg_and_die(bb_msg_requires_arg, "-i");
1486                 add_input_file(stdin);
1487         } else {
1488                 int i;
1489
1490                 for (i = 0; argv[i]; i++) {
1491                         struct stat statbuf;
1492                         int nonstdoutfd;
1493                         FILE *file;
1494                         sed_cmd_t *sed_cmd;
1495
1496                         if (LONE_DASH(argv[i]) && !(opt & OPT_in_place)) {
1497                                 add_input_file(stdin);
1498                                 process_files();
1499                                 continue;
1500                         }
1501                         file = fopen_or_warn(argv[i], "r");
1502                         if (!file) {
1503                                 status = EXIT_FAILURE;
1504                                 continue;
1505                         }
1506                         add_input_file(file);
1507                         if (!(opt & OPT_in_place)) {
1508                                 continue;
1509                         }
1510
1511                         /* -i: process each FILE separately: */
1512
1513                         G.outname = xasprintf("%sXXXXXX", argv[i]);
1514                         nonstdoutfd = xmkstemp(G.outname);
1515                         G.nonstdout = xfdopen_for_write(nonstdoutfd);
1516
1517                         /* Set permissions/owner of output file */
1518                         fstat(fileno(file), &statbuf);
1519                         /* chmod'ing AFTER chown would preserve suid/sgid bits,
1520                          * but GNU sed 4.2.1 does not preserve them either */
1521                         fchmod(nonstdoutfd, statbuf.st_mode);
1522                         fchown(nonstdoutfd, statbuf.st_uid, statbuf.st_gid);
1523
1524                         process_files();
1525                         fclose(G.nonstdout);
1526                         G.nonstdout = stdout;
1527
1528                         if (opt_i) {
1529                                 char *backupname = xasprintf("%s%s", argv[i], opt_i);
1530                                 xrename(argv[i], backupname);
1531                                 free(backupname);
1532                         }
1533                         /* else unlink(argv[i]); - rename below does this */
1534                         xrename(G.outname, argv[i]); //TODO: rollback backup on error?
1535                         free(G.outname);
1536                         G.outname = NULL;
1537
1538                         /* Re-enable disabled range matches */
1539                         for (sed_cmd = G.sed_cmd_head; sed_cmd; sed_cmd = sed_cmd->next) {
1540                                 sed_cmd->beg_line = sed_cmd->beg_line_orig;
1541                         }
1542                 }
1543                 /* Here, to handle "sed 'cmds' nonexistent_file" case we did:
1544                  * if (G.current_input_file >= G.input_file_count)
1545                  *      return status;
1546                  * but it's not needed since process_files() works correctly
1547                  * in this case too. */
1548         }
1549         process_files();
1550
1551         return status;
1552 }