/* * sed.c - very minimalist version of sed * * Copyright (C) 1999,2000,2001 by Lineo, inc. * Written by Mark Whitley <markw@lineo.com>, <markw@codepoet.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ /* Supported features and commands in this version of sed: - comments ('#') - address matching: num|/matchstr/[,num|/matchstr/|$]command - commands: (p)rint, (d)elete, (s)ubstitue (with g & I flags) - edit commands: (a)ppend, (i)nsert, (c)hange - backreferences in substitution expressions (\1, \2...\9) (Note: Specifying an address (range) to match is *optional*; commands default to the whole pattern space if no specific address match was requested.) Unsupported features: - transliteration (y/source-chars/dest-chars/) (use 'tr') - no pattern space hold space storing / swapping (x, etc.) - no labels / branching (: label, b, t, and friends) - and lots, lots more. */ #include <stdio.h> #include <unistd.h> /* for getopt() */ #include <regex.h> #include <string.h> /* for strdup() */ #include <errno.h> #include <ctype.h> /* for isspace() */ #include <stdlib.h> #include "busybox.h" /* externs */ extern void xregcomp(regex_t *preg, const char *regex, int cflags); extern int optind; /* in unistd.h */ extern char *optarg; /* ditto */ /* options */ static int be_quiet = 0; struct sed_cmd { /* GENERAL FIELDS */ char delimiter; /* The delimiter used to separate regexps */ /* address storage */ int beg_line; /* 'sed 1p' 0 == no begining line, apply commands to all lines */ int end_line; /* 'sed 1,3p' 0 == no end line, use only beginning. -1 == $ */ regex_t *beg_match; /* sed -e '/match/cmd' */ regex_t *end_match; /* sed -e '/match/,/end_match/cmd' */ /* the command */ char cmd; /* p,d,s (add more at your leisure :-) */ /* SUBSTITUTION COMMAND SPECIFIC FIELDS */ /* sed -e 's/sub_match/replace/' */ regex_t *sub_match; char *replace; unsigned int num_backrefs:4; /* how many back references (\1..\9) */ /* Note: GNU/POSIX sed does not save more than nine backrefs, so * we only use 4 bits to hold the number */ unsigned int sub_g:1; /* sed -e 's/foo/bar/g' (global) */ unsigned int sub_p:2; /* sed -e 's/foo/bar/p' (print substitution) */ /* EDIT COMMAND (a,i,c) SPEICIFIC FIELDS */ char *editline; }; /* globals */ static struct sed_cmd *sed_cmds = NULL; /* growable arrary holding a sequence of sed cmds */ static int ncmds = 0; /* number of sed commands */ /*static char *cur_file = NULL;*/ /* file currently being processed XXX: do I need this? */ #ifdef BB_FEATURE_CLEAN_UP static void destroy_cmd_strs() { if (sed_cmds == NULL) return; /* destroy all the elements in the array */ while (--ncmds >= 0) { if (sed_cmds[ncmds].beg_match) { regfree(sed_cmds[ncmds].beg_match); free(sed_cmds[ncmds].beg_match); } if (sed_cmds[ncmds].end_match) { regfree(sed_cmds[ncmds].end_match); free(sed_cmds[ncmds].end_match); } if (sed_cmds[ncmds].sub_match) { regfree(sed_cmds[ncmds].sub_match); free(sed_cmds[ncmds].sub_match); } if (sed_cmds[ncmds].replace) free(sed_cmds[ncmds].replace); } /* destroy the array */ free(sed_cmds); sed_cmds = NULL; } #endif /* * index_of_next_unescaped_regexp_delim - walks left to right through a string * beginning at a specified index and returns the index of the next regular * expression delimiter (typically a forward * slash ('/')) not preceeded by * a backslash ('\'). */ static int index_of_next_unescaped_regexp_delim(struct sed_cmd *sed_cmd, const char *str, int idx) { for ( ; str[idx]; idx++) { if (str[idx] == sed_cmd->delimiter && str[idx-1] != '\\') return idx; } /* if we make it to here, we've hit the end of the string */ return -1; } /* * returns the index in the string just past where the address ends. */ static int get_address(struct sed_cmd *sed_cmd, const char *str, int *line, regex_t **regex) { char *my_str = strdup(str); int idx = 0; char olddelimiter; olddelimiter = sed_cmd->delimiter; sed_cmd->delimiter = '/'; if (isdigit(my_str[idx])) { do { idx++; } while (isdigit(my_str[idx])); my_str[idx] = 0; *line = atoi(my_str); } else if (my_str[idx] == '$') { *line = -1; idx++; } else if (my_str[idx] == '/') { idx = index_of_next_unescaped_regexp_delim(sed_cmd, my_str, ++idx); if (idx == -1) error_msg_and_die("unterminated match expression"); my_str[idx] = '\0'; *regex = (regex_t *)xmalloc(sizeof(regex_t)); xregcomp(*regex, my_str+1, 0); idx++; /* so it points to the next character after the last '/' */ } else { error_msg("get_address: no address found in string\n" "\t(you probably didn't check the string you passed me)"); idx = -1; } free(my_str); sed_cmd->delimiter = olddelimiter; return idx; } static char *strdup_substr(const char *str, int start, int end) { int size = end - start + 1; char *newstr = xmalloc(size); memcpy(newstr, str+start, size-1); newstr[size-1] = '\0'; return newstr; } static int parse_subst_cmd(struct sed_cmd *sed_cmd, const char *substr) { int oldidx, cflags = REG_NEWLINE; char *match; int idx = 0; int j; /* * the string that gets passed to this function should look like this: * s/match/replace/gIp * || | ||| * mandatory optional * * (all three of the '/' slashes are mandatory) */ /* verify that the 's' is followed by something. That something * (typically a 'slash') is now our regexp delimiter... */ if (!substr[++idx]) error_msg_and_die("bad format in substitution expression"); else sed_cmd->delimiter=substr[idx]; /* save the match string */ oldidx = idx+1; idx = index_of_next_unescaped_regexp_delim(sed_cmd, substr, ++idx); if (idx == -1) error_msg_and_die("bad format in substitution expression"); match = strdup_substr(substr, oldidx, idx); /* determine the number of back references in the match string */ /* Note: we compute this here rather than in the do_subst_command() * function to save processor time, at the expense of a little more memory * (4 bits) per sed_cmd */ /* sed_cmd->num_backrefs = 0; */ /* XXX: not needed? --apparently not */ for (j = 0; match[j]; j++) { /* GNU/POSIX sed does not save more than nine backrefs */ if (match[j] == '\\' && match[j+1] == '(' && sed_cmd->num_backrefs <= 9) sed_cmd->num_backrefs++; } /* save the replacement string */ oldidx = idx+1; idx = index_of_next_unescaped_regexp_delim(sed_cmd, substr, ++idx); if (idx == -1) error_msg_and_die("bad format in substitution expression"); sed_cmd->replace = strdup_substr(substr, oldidx, idx); /* process the flags */ while (substr[++idx]) { switch (substr[idx]) { case 'g': sed_cmd->sub_g = 1; break; case 'I': cflags |= REG_ICASE; break; case 'p': sed_cmd->sub_p = 1; break; default: /* any whitespace or semicolon trailing after a s/// is ok */ if (strchr("; \t\v\n\r", substr[idx])) goto out; /* else */ error_msg_and_die("bad option in substitution expression"); } } out: /* compile the match string into a regex */ sed_cmd->sub_match = (regex_t *)xmalloc(sizeof(regex_t)); xregcomp(sed_cmd->sub_match, match, cflags); free(match); return idx; } static int parse_edit_cmd(struct sed_cmd *sed_cmd, const char *editstr) { int idx = 0; int slashes_eaten = 0; char *ptr; /* shorthand */ /* * the string that gets passed to this function should look like this: * * need one of these * | * | this backslash (immediately following the edit command) is mandatory * | | * [aic]\ * TEXT1\ * TEXT2\ * TEXTN * * as soon as we hit a TEXT line that has no trailing '\', we're done. * this means a command like: * * i\ * INSERTME * * is a-ok. * */ if (editstr[1] != '\\' && (editstr[2] != '\n' || editstr[2] != '\r')) error_msg_and_die("bad format in edit expression"); /* store the edit line text */ /* make editline big enough to accomodate the extra '\n' we will tack on * to the end */ sed_cmd->editline = xmalloc(strlen(&editstr[3]) + 2); strcpy(sed_cmd->editline, &editstr[3]); ptr = sed_cmd->editline; /* now we need to go through * and: s/\\[\r\n]$/\n/g on the edit line */ while (ptr[idx]) { while (ptr[idx] != '\\' || (ptr[idx+1] != '\n' && ptr[idx+1] != '\r')) { idx++; if (!ptr[idx]) { goto out; } } /* move the newline over the '\' before it (effectively eats the '\') */ memmove(&ptr[idx], &ptr[idx+1], strlen(&ptr[idx+1])); ptr[strlen(ptr)-1] = 0; slashes_eaten++; /* substitue \r for \n if needed */ if (ptr[idx] == '\r') ptr[idx] = '\n'; } out: /* this accounts for discrepancies between the modified string and the * original string passed in to this function */ idx += slashes_eaten; /* figure out if we need to add a newline */ if (ptr[idx-1] != '\n') { ptr[idx] = '\n'; idx++; } /* terminate string */ ptr[idx]= 0; /* adjust for opening 2 chars [aic]\ */ idx += 2; return idx; } static char *parse_cmd_str(struct sed_cmd *sed_cmd, const char *cmdstr) { int idx = 0; /* parse the command * format is: [addr][,addr]cmd * |----||-----||-| * part1 part2 part3 */ /* first part (if present) is an address: either a number or a /regex/ */ if (isdigit(cmdstr[idx]) || cmdstr[idx] == '/') idx = get_address(sed_cmd, cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match); /* second part (if present) will begin with a comma */ if (cmdstr[idx] == ',') idx += get_address(sed_cmd, &cmdstr[++idx], &sed_cmd->end_line, &sed_cmd->end_match); /* last part (mandatory) will be a command */ if (cmdstr[idx] == '\0') error_msg_and_die("missing command"); if (!strchr("pdsaic", cmdstr[idx])) /* <-- XXX add new commands here */ error_msg_and_die("invalid command"); sed_cmd->cmd = cmdstr[idx]; /* special-case handling for (s)ubstitution */ if (sed_cmd->cmd == 's') { idx += parse_subst_cmd(sed_cmd, &cmdstr[idx]); } /* special-case handling for (a)ppend, (i)nsert, and (c)hange */ else if (strchr("aic", cmdstr[idx])) { if (sed_cmd->end_line || sed_cmd->end_match) error_msg_and_die("only a beginning address can be specified for edit commands"); idx += parse_edit_cmd(sed_cmd, &cmdstr[idx]); } /* if it was a single-letter command (such as 'p' or 'd') we need to * increment the index past that command */ else idx++; /* give back whatever's left over */ return (char *)&cmdstr[idx]; } static void add_cmd_str(const char *cmdstr) { char *mystr = (char *)cmdstr; do { /* trim leading whitespace and semicolons */ memmove(mystr, &mystr[strspn(mystr, "; \n\r\t\v")], strlen(mystr)); /* if we ate the whole thing, that means there was just trailing * whitespace or a final / no-op semicolon. either way, get out */ if (strlen(mystr) == 0) return; /* if this is a comment, jump past it and keep going */ if (mystr[0] == '#') { mystr = strpbrk(mystr, ";\n\r"); continue; } /* grow the array */ sed_cmds = xrealloc(sed_cmds, sizeof(struct sed_cmd) * (++ncmds)); /* zero new element */ memset(&sed_cmds[ncmds-1], 0, sizeof(struct sed_cmd)); /* load command string into new array element, get remainder */ mystr = parse_cmd_str(&sed_cmds[ncmds-1], mystr); } while (mystr && strlen(mystr)); } static void load_cmd_file(char *filename) { FILE *cmdfile; char *line; char *nextline; cmdfile = xfopen(filename, "r"); while ((line = get_line_from_file(cmdfile)) != NULL) { /* if a line ends with '\' it needs the next line appended to it */ while (line[strlen(line)-2] == '\\' && (nextline = get_line_from_file(cmdfile)) != NULL) { line = xrealloc(line, strlen(line) + strlen(nextline) + 1); strcat(line, nextline); free(nextline); } /* eat trailing newline (if any) --if I don't do this, edit commands * (aic) will print an extra newline */ chomp(line); add_cmd_str(line); free(line); } } static void print_subst_w_backrefs(const char *line, const char *replace, regmatch_t *regmatch) { int i; /* go through the replacement string */ for (i = 0; replace[i]; i++) { /* if we find a backreference (\1, \2, etc.) print the backref'ed * text */ if (replace[i] == '\\' && isdigit(replace[i+1])) { int j; char tmpstr[2]; int backref; ++i; /* i now indexes the backref number, instead of the leading slash */ tmpstr[0] = replace[i]; tmpstr[1] = 0; backref = atoi(tmpstr); /* print out the text held in regmatch[backref] */ for (j = regmatch[backref].rm_so; j < regmatch[backref].rm_eo; j++) fputc(line[j], stdout); } /* if we find a backslash escaped character, print the character */ else if (replace[i] == '\\') { ++i; fputc(replace[i], stdout); } /* if we find an unescaped '&' print out the whole matched text. * fortunately, regmatch[0] contains the indicies to the whole matched * expression (kinda seems like it was designed for just such a * purpose...) */ else if (replace[i] == '&' && replace[i-1] != '\\') { int j; for (j = regmatch[0].rm_so; j < regmatch[0].rm_eo; j++) fputc(line[j], stdout); } /* nothing special, just print this char of the replacement string to stdout */ else fputc(replace[i], stdout); } } static int do_subst_command(const struct sed_cmd *sed_cmd, const char *line) { char *hackline = (char *)line; int altered = 0; regmatch_t *regmatch = NULL; /* we only proceed if the substitution 'search' expression matches */ if (regexec(sed_cmd->sub_match, line, 0, NULL, 0) == REG_NOMATCH) return 0; /* whaddaya know, it matched. get the number of back references */ regmatch = xmalloc(sizeof(regmatch_t) * (sed_cmd->num_backrefs+1)); /* and now, as long as we've got a line to try matching and if we can match * the search string, we make substitutions */ while (*hackline && (regexec(sed_cmd->sub_match, hackline, sed_cmd->num_backrefs+1, regmatch, 0) == 0) ) { int i; /* print everything before the match */ for (i = 0; i < regmatch[0].rm_so; i++) fputc(hackline[i], stdout); /* then print the substitution string */ print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch); /* advance past the match */ hackline += regmatch[0].rm_eo; /* flag that something has changed */ altered++; /* if we're not doing this globally, get out now */ if (!sed_cmd->sub_g) break; } /* if there's anything left of the line, print it */ if (*hackline) fputs(hackline, stdout); /* cleanup */ free(regmatch); return altered; } static int do_sed_command(const struct sed_cmd *sed_cmd, const char *line) { int altered = 0; switch (sed_cmd->cmd) { case 'p': fputs(line, stdout); break; case 'd': altered++; break; case 's': /* * Some special cases for 's' printing to make it compliant with * GNU sed printing behavior (aka "The -n | s///p Matrix"): * * -n ONLY = never print anything regardless of any successful * substitution * * s///p ONLY = always print successful substitutions, even if * the line is going to be printed anyway (line will be printed * twice). * * -n AND s///p = print ONLY a successful substitution ONE TIME; * no other lines are printed - this is the reason why the 'p' * flag exists in the first place. */ /* if the user specified that they didn't want anything printed (i.e. a -n * flag and no 'p' flag after the s///), then there's really no point doing * anything here. */ if (be_quiet && !sed_cmd->sub_p) break; /* we print the line once, unless we were told to be quiet */ if (!be_quiet) altered = do_subst_command(sed_cmd, line); /* we also print the line if we were given the 'p' flag * (this is quite possibly the second printing) */ if (sed_cmd->sub_p) altered = do_subst_command(sed_cmd, line); break; case 'a': fputs(line, stdout); fputs(sed_cmd->editline, stdout); altered++; break; case 'i': fputs(sed_cmd->editline, stdout); break; case 'c': fputs(sed_cmd->editline, stdout); altered++; break; } return altered; } static void process_file(FILE *file) { char *line = NULL; static int linenum = 0; /* GNU sed does not restart counting lines at EOF */ unsigned int still_in_range = 0; int line_altered; int i; /* go through every line in the file */ while ((line = get_line_from_file(file)) != NULL) { linenum++; line_altered = 0; /* for every line, go through all the commands */ for (i = 0; i < ncmds; i++) { /* are we acting on a range of matched lines? */ if (sed_cmds[i].beg_match && sed_cmds[i].end_match) { if (still_in_range || regexec(sed_cmds[i].beg_match, line, 0, NULL, 0) == 0) { line_altered += do_sed_command(&sed_cmds[i], line); if (still_in_range && regexec(sed_cmds[i].end_match, line, 0, NULL, 0) == 0) still_in_range = 0; else still_in_range = 1; } } /* are we trying to match a single line? */ else if (sed_cmds[i].beg_match) { if (regexec(sed_cmds[i].beg_match, line, 0, NULL, 0) == 0) line_altered += do_sed_command(&sed_cmds[i], line); } /* are we acting on a range of line numbers? */ else if (sed_cmds[i].beg_line > 0 && sed_cmds[i].end_line != 0) { if (linenum >= sed_cmds[i].beg_line && (sed_cmds[i].end_line == -1 || linenum <= sed_cmds[i].end_line)) line_altered += do_sed_command(&sed_cmds[i], line); } /* are we acting on a specified line number */ else if (sed_cmds[i].beg_line > 0) { if (linenum == sed_cmds[i].beg_line) line_altered += do_sed_command(&sed_cmds[i], line); } /* not acting on matches or line numbers. act on every line */ else line_altered += do_sed_command(&sed_cmds[i], line); } /* we will print the line unless we were told to be quiet or if the * line was altered (via a 'd'elete or 's'ubstitution), in which case * the altered line was already printed */ if (!be_quiet && !line_altered) fputs(line, stdout); free(line); } } extern int sed_main(int argc, char **argv) { int opt; #ifdef BB_FEATURE_CLEAN_UP /* destroy command strings on exit */ if (atexit(destroy_cmd_strs) == -1) perror_msg_and_die("atexit"); #endif /* do normal option parsing */ while ((opt = getopt(argc, argv, "ne:f:")) > 0) { switch (opt) { case 'n': be_quiet++; break; case 'e': add_cmd_str(optarg); break; case 'f': load_cmd_file(optarg); break; default: show_usage(); } } /* if we didn't get a pattern from a -e and no command file was specified, * argv[optind] should be the pattern. no pattern, no worky */ if (ncmds == 0) { if (argv[optind] == NULL) show_usage(); else { add_cmd_str(argv[optind]); optind++; } } /* argv[(optind)..(argc-1)] should be names of file to process. If no * files were specified or '-' was specified, take input from stdin. * Otherwise, we process all the files specified. */ if (argv[optind] == NULL || (strcmp(argv[optind], "-") == 0)) { process_file(stdin); } else { int i; FILE *file; for (i = optind; i < argc; i++) { file = fopen(argv[i], "r"); if (file == NULL) { perror_msg("%s", argv[i]); } else { process_file(file); fclose(file); } } } return 0; }