busybox/sed.c
Mark Whitley 464c5de00d Fixed a couple of buglets:
- add_cmd_str: segv's were being generated if there was a '# comment' line
   (and probably other kinds of lines, too) that was not followed by a
   semi-colon or whitespace
 - parse_edit_cmd: was returning a wrong number (too low) for the index; it
   was not accounting for backslashes eaten, for the fact that we start at the
   3rd index in the string, or for the fact that we add an extra newline.
 - parse_cmd_str: was returning a wrong number (again, too low) for the index
   in the case of single-letter commands (p,d). There was some
   over-compensation for this in the 'return' stmt at the end which also
   needed some help.
 - load_cmd_file: was not eating trailing newlines off the line read from the
   command file. This had the deleterious effect of printing an extra newlines
   after text displayed from edit (i,a,c) commands.
2000-07-14 23:24:00 +00:00

689 lines
17 KiB
C

/*
* sed.c - very minimalist version of sed
*
* Copyright (C) 1999,2000 by Lineo, inc.
* Written by Mark Whitley <markw@lineo.com>, <markw@enol.com>
*
* 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
(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 support for characters other than the '/' character for regex matches
- 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 <stdlib.h> /* for realloc() */
#include <unistd.h> /* for getopt() */
#include <regex.h>
#include <string.h> /* for strdup() */
#include <errno.h>
#include <ctype.h> /* for isspace() */
#include "internal.h"
/* externs */
extern int optind; /* in unistd.h */
extern char *optarg; /* ditto */
/* options */
static int be_quiet = 0;
struct sed_cmd {
/* 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 */
regex_t *sub_match; /* sed -e 's/sub_match/replace/' */
char *replace; /* sed -e 's/sub_match/replace/' XXX: who will hold the \1 \2 \3s? */
unsigned int sub_g:1; /* sed -e 's/foo/bar/g' (global) */
/* edit command (a,i,c) speicific field */
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? */
static const char sed_usage[] =
"sed [-Vhnef] pattern [files...]\n"
#ifndef BB_FEATURE_TRIVIAL_HELP
"\n"
"-n\tsuppress automatic printing of pattern space\n"
"-e script\tadd the script to the commands to be executed\n"
"-f scriptfile\tadd the contents of script-file to the commands to be executed\n"
"-h\tdisplay this help message\n"
"-V\toutput version information and exit\n"
"\n"
"If no -e or -f is given, the first non-option argument is taken as the\n"
"sed script to interpret. All remaining arguments are names of input\n"
"files; if no input files are specified, then the standard input is read.\n"
#endif
;
#if 0
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
#if 0
/*
* trim_str - trims leading and trailing space from a string
*
* Note: This returns a malloc'ed string so you must store and free it
* XXX: This should be in the utility.c file.
* XXX: This is now obsolete. Maybe it belongs nowhere.
*/
static char *trim_str(const char *str)
{
int i;
char *retstr = strdup(str);
/* trim leading whitespace */
memmove(retstr, &retstr[strspn(retstr, " \n\t\v")], strlen(retstr));
/* trim trailing whitespace */
i = strlen(retstr) - 1;
while (isspace(retstr[i]))
i--;
retstr[++i] = 0;
/* Aside:
*
* you know, a strrspn() would really be nice cuz then we could say:
*
* retstr[strrspn(retstr, " \n\t\v") + 1] = 0;
*/
return retstr;
}
#endif
#if 0
/*
* strrspn - works just like strspn() but goes from right to left instead of
* left to right
*/
static size_t strrspn(const char *s, const char *accept)
{
size_t i = strlen(s);
while (strchr(accept, s[--i]))
;
return i;
}
#endif
/*
* index_of_unescaped_slash - walks left to right through a string beginning
* at a specified index and returns the index of the next unescaped slash.
*/
static int index_of_next_unescaped_slash(const char *str, int idx)
{
do {
idx++;
/* test if we've hit the end */
if (str[idx] == 0)
return -1;
} while (str[idx] != '/' && str[idx - 1] != '\\');
return idx;
}
/*
* returns the index in the string just past where the address ends.
*/
static int get_address(const char *str, int *line, regex_t **regex)
{
char *my_str = strdup(str);
int idx = 0;
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_slash(my_str, idx);
if (idx == -1)
fatalError("unterminated match expression\n");
my_str[idx] = '\0';
*regex = (regex_t *)xmalloc(sizeof(regex_t));
xregcomp(*regex, my_str+1, REG_NEWLINE);
idx++; /* so it points to the next character after the last '/' */
}
else {
errorMsg("get_address: no address found in string\n"
"\t(you probably didn't check the string you passed me)\n");
idx = -1;
}
free(my_str);
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;
/*
* the string that gets passed to this function should look like this:
* s/match/replace/gI
* || | ||
* mandatory optional
*
* (all three of the '/' slashes are mandatory)
*/
/* verify that the 's' is followed by a 'slash' */
if (substr[++idx] != '/')
fatalError("bad format in substitution expression\n");
/* save the match string */
oldidx = idx+1;
idx = index_of_next_unescaped_slash(substr, idx);
if (idx == -1)
fatalError("bad format in substitution expression\n");
match = strdup_substr(substr, oldidx, idx);
/* save the replacement string */
oldidx = idx+1;
idx = index_of_next_unescaped_slash(substr, idx);
if (idx == -1)
fatalError("bad format in substitution expression\n");
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;
default:
/* any whitespace or semicolon trailing after a s/// is ok */
if (strchr("; \t\v\n\r", substr[idx]))
goto out;
/* else */
fatalError("bad option in substitution expression\n");
}
}
out:
/* compile the 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'))
fatalError("bad format in edit expression\n");
/* 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:
ptr[idx] = '\n';
ptr[idx+1] = 0;
/* this accounts for discrepancies between the modified string and the
* original string passed in to this function */
idx += slashes_eaten;
/* this accounts for the fact that A) we started at index 3, not at index
* 0 and B) that we added an extra '\n' at the end (if you think the next
* line should read 'idx += 4' remember, arrays are zero-based) */
idx += 3;
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(cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
/* second part (if present) will begin with a comma */
if (cmdstr[idx] == ',')
idx += get_address(&cmdstr[++idx], &sed_cmd->end_line, &sed_cmd->end_match);
/* last part (mandatory) will be a command */
if (cmdstr[idx] == '\0')
fatalError("missing command\n");
if (!strchr("pdsaic", cmdstr[idx])) /* <-- XXX add new commands here */
fatalError("invalid command\n");
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)
fatalError("only a beginning address can be specified for edit commands\n");
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 = realloc(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 = fopen(filename, "r");
if (cmdfile == NULL)
fatalError(strerror(errno));
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 = realloc(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 */
if (line[strlen(line)-1] == '\n')
line[strlen(line)-1] = 0;
add_cmd_str(line);
free(line);
}
}
static int do_subst_command(const struct sed_cmd *sed_cmd, const char *line)
{
int altered = 0;
/* we only substitute if the substitution 'search' expression matches */
if (regexec(sed_cmd->sub_match, line, 0, NULL, 0) == 0) {
regmatch_t regmatch;
int i;
char *ptr = (char *)line;
while (*ptr) {
/* if we can match the search string... */
if (regexec(sed_cmd->sub_match, ptr, 1, &regmatch, 0) == 0) {
/* print everything before the match, */
for (i = 0; i < regmatch.rm_so; i++)
fputc(ptr[i], stdout);
/* then print the substitution in its place */
fputs(sed_cmd->replace, stdout);
/* then advance past the match */
ptr += regmatch.rm_eo;
/* and flag that something has changed */
altered++;
/* if we're not doing this globally... */
if (!sed_cmd->sub_g)
break;
}
/* if we COULD NOT match the search string (meaning we've gone past
* all previous instances), get out */
else
break;
}
/* is there anything left to print? */
if (*ptr)
fputs(ptr, stdout);
}
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':
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);
still_in_range = 1;
if (regexec(sed_cmds[i].end_match, line, 0, NULL, 0) == 0)
still_in_range = 0;
}
}
/* 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 && 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) */
if (!be_quiet && !line_altered)
fputs(line, stdout);
free(line);
}
}
extern int sed_main(int argc, char **argv)
{
int opt;
/* do special-case option parsing */
if (argv[1] && (strcmp(argv[1], "--help") == 0))
usage(sed_usage);
#if 0
/* destroy command strings on exit */
if (atexit(destroy_cmd_strs) == -1) {
perror("sed");
exit(1);
}
#endif
/* do normal option parsing */
while ((opt = getopt(argc, argv, "Vhne:f:")) > 0) {
switch (opt) {
case 'V':
printf("BusyBox v%s (%s)\n", BB_VER, BB_BT);
exit(0);
break;
case 'h':
usage(sed_usage);
break;
case 'n':
be_quiet++;
break;
case 'e':
add_cmd_str(optarg);
break;
case 'f':
load_cmd_file(optarg);
break;
}
}
/* 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)
usage(sed_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) {
errorMsg("%s: %s\n", argv[i], strerror(errno));
} else {
process_file(file);
fclose(file);
}
}
}
return 0;
}