2 * sed.c - very minimalist version of sed
4 * Copyright (C) 1999,2000,2001 by Lineo, inc. and Mark Whitley
5 * Copyright (C) 1999,2000,2001 by Mark Whitley <markw@codepoet.org>
6 * Copyright (C) 2002 Matt Kraai
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 Supported features and commands in this version of sed:
28 - address matching: num|/matchstr/[,num|/matchstr/|$]command
29 - commands: (p)rint, (d)elete, (s)ubstitue (with g & I flags)
30 - edit commands: (a)ppend, (i)nsert, (c)hange
31 - file commands: (r)ead
32 - backreferences in substitution expressions (\1, \2...\9)
34 (Note: Specifying an address (range) to match is *optional*; commands
35 default to the whole pattern space if no specific address match was
40 - transliteration (y/source-chars/dest-chars/) (use 'tr')
41 - no pattern space hold space storing / swapping (x, etc.)
42 - no labels / branching (: label, b, t, and friends)
43 - and lots, lots more.
47 #include <unistd.h> /* for getopt() */
49 #include <string.h> /* for strdup() */
51 #include <ctype.h> /* for isspace() */
56 extern void xregcomp(regex_t *preg, const char *regex, int cflags);
57 extern int optind; /* in unistd.h */
58 extern char *optarg; /* ditto */
61 static int be_quiet = 0;
65 /* Order by alignment requirements */
68 regex_t *beg_match; /* sed -e '/match/cmd' */
69 regex_t *end_match; /* sed -e '/match/,/end_match/cmd' */
71 /* SUBSTITUTION COMMAND SPECIFIC FIELDS */
73 /* sed -e 's/sub_match/replace/' */
77 /* EDIT COMMAND (a,i,c) SPECIFIC FIELDS */
80 /* FILE COMMAND (r) SPECIFIC FIELDS */
84 int beg_line; /* 'sed 1p' 0 == no begining line, apply commands to all lines */
85 int end_line; /* 'sed 1,3p' 0 == no end line, use only beginning. -1 == $ */
86 /* SUBSTITUTION COMMAND SPECIFIC FIELDS */
88 unsigned int num_backrefs:4; /* how many back references (\1..\9) */
89 /* Note: GNU/POSIX sed does not save more than nine backrefs, so
90 * we only use 4 bits to hold the number */
91 unsigned int sub_g:1; /* sed -e 's/foo/bar/g' (global) */
92 unsigned int sub_p:2; /* sed -e 's/foo/bar/p' (print substitution) */
95 char delimiter; /* The delimiter used to separate regexps */
98 char cmd; /* p,d,s (add more at your leisure :-) */
102 static struct sed_cmd *sed_cmds = NULL; /* growable arrary holding a sequence of sed cmds */
103 static int ncmds = 0; /* number of sed commands */
105 /*static char *cur_file = NULL;*/ /* file currently being processed XXX: do I need this? */
107 const char * const semicolon_whitespace = "; \n\r\t\v\0";
109 #ifdef CONFIG_FEATURE_CLEAN_UP
110 static void destroy_cmd_strs(void)
112 if (sed_cmds == NULL)
115 /* destroy all the elements in the array */
116 while (--ncmds >= 0) {
118 if (sed_cmds[ncmds].beg_match) {
119 regfree(sed_cmds[ncmds].beg_match);
120 free(sed_cmds[ncmds].beg_match);
122 if (sed_cmds[ncmds].end_match) {
123 regfree(sed_cmds[ncmds].end_match);
124 free(sed_cmds[ncmds].end_match);
126 if (sed_cmds[ncmds].sub_match) {
127 regfree(sed_cmds[ncmds].sub_match);
128 free(sed_cmds[ncmds].sub_match);
130 if (sed_cmds[ncmds].replace)
131 free(sed_cmds[ncmds].replace);
134 /* destroy the array */
142 * index_of_next_unescaped_regexp_delim - walks left to right through a string
143 * beginning at a specified index and returns the index of the next regular
144 * expression delimiter (typically a forward * slash ('/')) not preceeded by
147 static int index_of_next_unescaped_regexp_delim(const struct sed_cmd * const sed_cmd, const char *str, int idx)
153 for ( ; (ch = str[idx]); idx++) {
155 if (ch == ']' && !(bracket == idx - 1 ||
156 (bracket == idx - 2 && str[idx-1] == '^')))
164 else if (ch == sed_cmd->delimiter)
168 /* if we make it to here, we've hit the end of the string */
173 * returns the index in the string just past where the address ends.
175 static int get_address(struct sed_cmd *sed_cmd, const char *str, int *linenum, regex_t **regex)
177 char *my_str = xstrdup(str);
180 olddelimiter = sed_cmd->delimiter;
181 sed_cmd->delimiter = '/';
183 if (isdigit(my_str[idx])) {
186 } while (isdigit(my_str[idx]));
188 *linenum = atoi(my_str);
190 else if (my_str[idx] == '$') {
194 else if (my_str[idx] == '/') {
195 idx = index_of_next_unescaped_regexp_delim(sed_cmd, my_str, ++idx);
197 error_msg_and_die("unterminated match expression");
199 *regex = (regex_t *)xmalloc(sizeof(regex_t));
200 xregcomp(*regex, my_str+1, REG_NEWLINE);
201 idx++; /* so it points to the next character after the last '/' */
204 error_msg("get_address: no address found in string\n"
205 "\t(you probably didn't check the string you passed me)");
210 sed_cmd->delimiter = olddelimiter;
214 static int parse_subst_cmd(struct sed_cmd * const sed_cmd, const char *substr)
216 int oldidx, cflags = REG_NEWLINE;
222 * the string that gets passed to this function should look like this:
223 * s/match/replace/gIp
227 * (all three of the '/' slashes are mandatory)
230 /* verify that the 's' is followed by something. That something
231 * (typically a 'slash') is now our regexp delimiter... */
233 error_msg_and_die("bad format in substitution expression");
235 sed_cmd->delimiter=substr[idx];
237 /* save the match string */
239 idx = index_of_next_unescaped_regexp_delim(sed_cmd, substr, ++idx);
241 error_msg_and_die("bad format in substitution expression");
242 match = xstrndup(substr + oldidx, idx - oldidx);
244 /* determine the number of back references in the match string */
245 /* Note: we compute this here rather than in the do_subst_command()
246 * function to save processor time, at the expense of a little more memory
247 * (4 bits) per sed_cmd */
249 /* sed_cmd->num_backrefs = 0; */ /* XXX: not needed? --apparently not */
250 for (j = 0; match[j]; j++) {
251 /* GNU/POSIX sed does not save more than nine backrefs */
252 if (match[j] == '\\' && match[j+1] == '(' && sed_cmd->num_backrefs <= 9)
253 sed_cmd->num_backrefs++;
256 /* save the replacement string */
258 idx = index_of_next_unescaped_regexp_delim(sed_cmd, substr, ++idx);
260 error_msg_and_die("bad format in substitution expression");
261 sed_cmd->replace = xstrndup(substr + oldidx, idx - oldidx);
263 /* process the flags */
264 while (substr[++idx]) {
265 switch (substr[idx]) {
276 /* any whitespace or semicolon trailing after a s/// is ok */
277 if (strchr(semicolon_whitespace, substr[idx]))
280 error_msg_and_die("bad option in substitution expression");
285 /* compile the match string into a regex */
286 sed_cmd->sub_match = (regex_t *)xmalloc(sizeof(regex_t));
287 xregcomp(sed_cmd->sub_match, match, cflags);
293 static void move_back(char *str, int offset)
295 memmove(str, str + offset, strlen(str + offset) + 1);
298 static int parse_edit_cmd(struct sed_cmd *sed_cmd, const char *editstr)
303 * the string that gets passed to this function should look like this:
307 * | this backslash (immediately following the edit command) is mandatory
314 * as soon as we hit a TEXT line that has no trailing '\', we're done.
315 * this means a command like:
324 if (editstr[1] != '\\' || (editstr[2] != '\n' && editstr[2] != '\r'))
325 error_msg_and_die("bad format in edit expression");
327 /* store the edit line text */
328 sed_cmd->editline = xmalloc(strlen(&editstr[3]) + 2);
329 for (i = 3, j = 0; editstr[i] != '\0' && strchr("\r\n", editstr[i]) == NULL;
331 if (editstr[i] == '\\' && strchr("\n\r", editstr[i+1]) != NULL) {
332 sed_cmd->editline[j] = '\n';
335 sed_cmd->editline[j] = editstr[i];
338 /* figure out if we need to add a newline */
339 if (sed_cmd->editline[j-1] != '\n')
340 sed_cmd->editline[j++] = '\n';
342 /* terminate string */
343 sed_cmd->editline[j] = '\0';
349 static int parse_file_cmd(struct sed_cmd *sed_cmd, const char *filecmdstr)
355 * the string that gets passed to this function should look like this:
360 * optional whitespace
362 * re: the file to be read, the GNU manual says the following: "Note that
363 * if filename cannot be read, it is treated as if it were an empty file,
364 * without any error indication." Thus, all of the following commands are
367 * sed -e '1r noexist'
372 /* the file command may be followed by whitespace; move past it. */
373 while (isspace(filecmdstr[++idx]))
376 /* the first non-whitespace we get is a filename. the filename ends when we
377 * hit a normal sed command terminator or end of string */
378 filenamelen = strcspn(&filecmdstr[idx], semicolon_whitespace);
379 sed_cmd->filename = xmalloc(filenamelen + 1);
380 safe_strncpy(sed_cmd->filename, &filecmdstr[idx], filenamelen + 1);
382 return idx + filenamelen;
386 static char *parse_cmd_str(struct sed_cmd * const sed_cmd, const char *const cmdstr)
391 * format is: [addr][,addr]cmd
396 /* first part (if present) is an address: either a number or a /regex/ */
397 if (isdigit(cmdstr[idx]) || cmdstr[idx] == '/')
398 idx = get_address(sed_cmd, cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
400 /* second part (if present) will begin with a comma */
401 if (cmdstr[idx] == ',')
402 idx += get_address(sed_cmd, &cmdstr[++idx], &sed_cmd->end_line, &sed_cmd->end_match);
404 /* skip whitespace before the command */
405 while (isspace(cmdstr[idx]))
408 /* last part (mandatory) will be a command */
409 if (cmdstr[idx] == '\0')
410 error_msg_and_die("missing command");
411 sed_cmd->cmd = cmdstr[idx];
413 /* if it was a single-letter command that takes no arguments (such as 'p'
414 * or 'd') all we need to do is increment the index past that command */
415 if (strchr("pd", sed_cmd->cmd)) {
418 /* handle (s)ubstitution command */
419 else if (sed_cmd->cmd == 's') {
420 idx += parse_subst_cmd(sed_cmd, &cmdstr[idx]);
422 /* handle edit cmds: (a)ppend, (i)nsert, and (c)hange */
423 else if (strchr("aic", sed_cmd->cmd)) {
424 if ((sed_cmd->end_line || sed_cmd->end_match) && sed_cmd->cmd != 'c')
425 error_msg_and_die("only a beginning address can be specified for edit commands");
426 idx += parse_edit_cmd(sed_cmd, &cmdstr[idx]);
428 /* handle file cmds: (r)ead */
429 else if (sed_cmd->cmd == 'r') {
430 if (sed_cmd->end_line || sed_cmd->end_match)
431 error_msg_and_die("Command only uses one address");
432 idx += parse_file_cmd(sed_cmd, &cmdstr[idx]);
435 error_msg_and_die("invalid command");
438 /* give back whatever's left over */
439 return (char *)&cmdstr[idx];
442 static void add_cmd_str(const char * const cmdstr)
444 char *mystr = (char *)cmdstr;
448 /* trim leading whitespace and semicolons */
449 move_back(mystr, strspn(mystr, semicolon_whitespace));
450 /* if we ate the whole thing, that means there was just trailing
451 * whitespace or a final / no-op semicolon. either way, get out */
452 if (strlen(mystr) == 0)
454 /* if this is a comment, jump past it and keep going */
455 if (mystr[0] == '#') {
456 mystr = strpbrk(mystr, "\n\r");
460 sed_cmds = xrealloc(sed_cmds, sizeof(struct sed_cmd) * (++ncmds));
461 /* zero new element */
462 memset(&sed_cmds[ncmds-1], 0, sizeof(struct sed_cmd));
463 /* load command string into new array element, get remainder */
464 mystr = parse_cmd_str(&sed_cmds[ncmds-1], mystr);
466 } while (mystr && strlen(mystr));
470 static void load_cmd_file(char *filename)
476 cmdfile = xfopen(filename, "r");
478 while ((line = get_line_from_file(cmdfile)) != NULL) {
479 /* if a line ends with '\' it needs the next line appended to it */
480 while (line[strlen(line)-2] == '\\' &&
481 (nextline = get_line_from_file(cmdfile)) != NULL) {
482 line = xrealloc(line, strlen(line) + strlen(nextline) + 1);
483 strcat(line, nextline);
486 /* eat trailing newline (if any) --if I don't do this, edit commands
487 * (aic) will print an extra newline */
500 #define PIPE_MAGIC 0x7f
503 void pipe_putc(struct pipeline *const pipeline, char c)
505 if (pipeline->buf[pipeline->idx] == PIPE_MAGIC) {
507 xrealloc(pipeline->buf, pipeline->len + PIPE_GROW);
508 memset(pipeline->buf + pipeline->len, 0, PIPE_GROW);
509 pipeline->len += PIPE_GROW;
510 pipeline->buf[pipeline->len - 1] = PIPE_MAGIC;
512 pipeline->buf[pipeline->idx++] = (c);
515 #define pipeputc(c) pipe_putc(pipeline, c)
518 { if (pipeline[pipeline_idx] == PIPE_MAGIC) { \
519 pipeline = xrealloc(pipeline, pipeline_len+PIPE_GROW); \
520 memset(pipeline+pipeline_len, 0, PIPE_GROW); \
521 pipeline_len += PIPE_GROW; \
522 pipeline[pipeline_len-1] = PIPE_MAGIC; } \
523 pipeline[pipeline_idx++] = (c); }
526 static void print_subst_w_backrefs(const char *line, const char *replace,
527 regmatch_t *regmatch, struct pipeline *const pipeline, int matches)
531 /* go through the replacement string */
532 for (i = 0; replace[i]; i++) {
533 /* if we find a backreference (\1, \2, etc.) print the backref'ed * text */
534 if (replace[i] == '\\' && isdigit(replace[i+1])) {
538 ++i; /* i now indexes the backref number, instead of the leading slash */
539 tmpstr[0] = replace[i];
541 backref = atoi(tmpstr);
542 /* print out the text held in regmatch[backref] */
543 if (backref <= matches && regmatch[backref].rm_so != -1)
544 for (j = regmatch[backref].rm_so; j < regmatch[backref].rm_eo; j++)
548 /* if we find a backslash escaped character, print the character */
549 else if (replace[i] == '\\') {
551 pipeputc(replace[i]);
554 /* if we find an unescaped '&' print out the whole matched text.
555 * fortunately, regmatch[0] contains the indicies to the whole matched
556 * expression (kinda seems like it was designed for just such a
558 else if (replace[i] == '&' && replace[i-1] != '\\') {
560 for (j = regmatch[0].rm_so; j < regmatch[0].rm_eo; j++)
563 /* nothing special, just print this char of the replacement string to stdout */
565 pipeputc(replace[i]);
569 static int do_subst_command(const struct sed_cmd *sed_cmd, char **line)
571 char *hackline = *line;
572 struct pipeline thepipe = { NULL, 0 , 0};
573 struct pipeline *const pipeline = &thepipe;
575 regmatch_t *regmatch = NULL;
577 /* we only proceed if the substitution 'search' expression matches */
578 if (regexec(sed_cmd->sub_match, hackline, 0, NULL, 0) == REG_NOMATCH)
581 /* whaddaya know, it matched. get the number of back references */
582 regmatch = xmalloc(sizeof(regmatch_t) * (sed_cmd->num_backrefs+1));
584 /* allocate more PIPE_GROW bytes
585 if replaced string is larger than original */
586 thepipe.len = strlen(hackline)+PIPE_GROW;
587 thepipe.buf = xcalloc(1, thepipe.len);
589 thepipe.buf[thepipe.len-1] = PIPE_MAGIC;
591 /* and now, as long as we've got a line to try matching and if we can match
592 * the search string, we make substitutions */
593 while ((*hackline || !altered) && (regexec(sed_cmd->sub_match, hackline,
594 sed_cmd->num_backrefs+1, regmatch, 0) != REG_NOMATCH) ) {
597 /* print everything before the match */
598 for (i = 0; i < regmatch[0].rm_so; i++)
599 pipeputc(hackline[i]);
601 /* then print the substitution string */
602 print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch,
603 pipeline, sed_cmd->num_backrefs);
605 /* advance past the match */
606 hackline += regmatch[0].rm_eo;
607 /* flag that something has changed */
610 /* if we're not doing this globally, get out now */
615 for (; *hackline; hackline++) pipeputc(*hackline);
616 if (thepipe.buf[thepipe.idx] == PIPE_MAGIC) thepipe.buf[thepipe.idx] = 0;
627 static void process_file(FILE *file)
630 static int linenum = 0; /* GNU sed does not restart counting lines at EOF */
631 unsigned int still_in_range = 0;
635 /* go through every line in the file */
636 while ((line = get_line_from_file(file)) != NULL) {
642 /* for every line, go through all the commands */
643 for (i = 0; i < ncmds; i++) {
644 struct sed_cmd *sed_cmd = &sed_cmds[i];
648 * entry point into sedding...
651 /* no range necessary */
652 (sed_cmd->beg_line == 0 && sed_cmd->end_line == 0 &&
653 sed_cmd->beg_match == NULL &&
654 sed_cmd->end_match == NULL) ||
655 /* this line number is the first address we're looking for */
656 (sed_cmd->beg_line && (sed_cmd->beg_line == linenum)) ||
657 /* this line matches our first address regex */
658 (sed_cmd->beg_match && (regexec(sed_cmd->beg_match, line, 0, NULL, 0) == 0)) ||
659 /* we are currently within the beginning & ending address range */
667 switch (sed_cmd->cmd) {
681 * Some special cases for 's' printing to make it compliant with
682 * GNU sed printing behavior (aka "The -n | s///p Matrix"):
684 * -n ONLY = never print anything regardless of any successful
687 * s///p ONLY = always print successful substitutions, even if
688 * the line is going to be printed anyway (line will be printed
691 * -n AND s///p = print ONLY a successful substitution ONE TIME;
692 * no other lines are printed - this is the reason why the 'p'
693 * flag exists in the first place.
696 /* if the user specified that they didn't want anything printed (i.e., a -n
697 * flag and no 'p' flag after the s///), then there's really no point doing
699 if (be_quiet && !sed_cmd->sub_p)
702 /* we print the line once, unless we were told to be quiet */
704 altered |= do_subst_command(sed_cmd, &line);
706 /* we also print the line if we were given the 'p' flag
707 * (this is quite possibly the second printing) */
709 altered |= do_subst_command(sed_cmd, &line);
710 if (altered && (i+1 >= ncmds || sed_cmds[i+1].cmd != 's'))
717 fputs(sed_cmd->editline, stdout);
722 fputs(sed_cmd->editline, stdout);
726 /* single-address case */
727 if ((sed_cmd->end_match == NULL && sed_cmd->end_line == 0)
728 /* multi-address case */
729 /* - matching text */
730 || (sed_cmd->end_match && (regexec(sed_cmd->end_match, line, 0, NULL, 0) == 0))
731 /* - matching line numbers */
732 || (sed_cmd->end_line > 0 && sed_cmd->end_line == linenum))
734 fputs(sed_cmd->editline, stdout);
743 outfile = fopen(sed_cmd->filename, "r");
746 /* else if we couldn't open the output file,
747 * no biggie, just don't print anything */
754 * exit point from sedding...
757 /* this is a single-address command or... */
758 (sed_cmd->end_line == 0 && sed_cmd->end_match == NULL) || (
759 /* we were in the middle of our address range (this
760 * isn't the first time through) and.. */
761 (still_in_range == 1) && (
762 /* this line number is the last address we're looking for or... */
763 (sed_cmd->end_line && (sed_cmd->end_line == linenum)) ||
764 /* this line matches our last address regex */
765 (sed_cmd->end_match && (regexec(sed_cmd->end_match, line, 0, NULL, 0) == 0))
769 /* we're out of our address range */
773 /* didn't hit the exit? then we're still in the middle of an address range */
783 /* we will print the line unless we were told to be quiet or if the
784 * line was altered (via a 'd'elete or 's'ubstitution), in which case
785 * the altered line was already printed */
786 if (!be_quiet && !altered)
793 extern int sed_main(int argc, char **argv)
795 int opt, status = EXIT_SUCCESS;
797 #ifdef CONFIG_FEATURE_CLEAN_UP
798 /* destroy command strings on exit */
799 if (atexit(destroy_cmd_strs) == -1)
800 perror_msg_and_die("atexit");
803 /* do normal option parsing */
804 while ((opt = getopt(argc, argv, "ne:f:")) > 0) {
813 load_cmd_file(optarg);
820 /* if we didn't get a pattern from a -e and no command file was specified,
821 * argv[optind] should be the pattern. no pattern, no worky */
823 if (argv[optind] == NULL)
826 add_cmd_str(argv[optind]);
832 /* argv[(optind)..(argc-1)] should be names of file to process. If no
833 * files were specified or '-' was specified, take input from stdin.
834 * Otherwise, we process all the files specified. */
835 if (argv[optind] == NULL || (strcmp(argv[optind], "-") == 0)) {
841 for (i = optind; i < argc; i++) {
842 file = wfopen(argv[i], "r");
847 status = EXIT_FAILURE;