busybox/editors/patch.c

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/* vi: set sw=4 ts=4: */
/*
* busybox patch applet to handle the unified diff format.
2007-09-21 18:46:32 +05:30
* Copyright (C) 2003 Glenn McGrath
*
* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*
* This applet is written to work with patches generated by GNU diff,
* where there is equivalent functionality busybox patch shall behave
* as per GNU patch.
*
* There is a SUSv3 specification for patch, however it looks to be
* incomplete, it doesnt even mention unified diff format.
* http://www.opengroup.org/onlinepubs/007904975/utilities/patch.html
*
* Issues
* - Non-interactive
* - Patches must apply cleanly or patch (not just one hunk) will fail.
* - Reject file isnt saved
*/
#include "libbb.h"
static unsigned copy_lines(FILE *src_stream, FILE *dst_stream, unsigned lines_count)
{
while (src_stream && lines_count) {
char *line;
line = xmalloc_fgets(src_stream);
if (line == NULL) {
break;
}
if (fputs(line, dst_stream) == EOF) {
bb_perror_msg_and_die("error writing to new file");
}
free(line);
lines_count--;
}
return lines_count;
}
/* If patch_level is -1 it will remove all directory names
* char *line must be greater than 4 chars
* returns NULL if the file doesnt exist or error
* returns malloc'ed filename
* NB: frees 1st argument!
*/
static char *extract_filename(char *line, int patch_level, const char *pat)
{
char *temp = NULL, *filename_start_ptr = line + 4;
if (strncmp(line, pat, 4) == 0) {
/* Terminate string at end of source filename */
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line[strcspn(line, "\t\n\r")] = '\0';
/* Skip over (patch_level) number of leading directories */
while (patch_level--) {
temp = strchr(filename_start_ptr, '/');
if (!temp)
break;
filename_start_ptr = temp + 1;
}
temp = xstrdup(filename_start_ptr);
}
free(line);
return temp;
}
int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int patch_main(int argc UNUSED_PARAM, char **argv)
{
struct stat saved_stat;
char *patch_line;
FILE *patch_file;
int patch_level;
int ret = 0;
char plus = '+';
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xfunc_error_retval = 2;
{
const char *p = "-1";
const char *i = "-"; /* compat */
if (getopt32(argv, "p:i:R", &p, &i) & 4)
plus = '-';
patch_level = xatoi(p); /* can be negative! */
patch_file = xfopen_stdin(i);
}
patch_line = xmalloc_fgetline(patch_file);
while (patch_line) {
FILE *src_stream;
FILE *dst_stream;
//char *old_filename;
char *new_filename;
char *backup_filename;
unsigned src_cur_line = 1;
unsigned dst_cur_line = 0;
unsigned dst_beg_line;
unsigned bad_hunk_count = 0;
unsigned hunk_count = 0;
smallint copy_trailing_lines_flag = 0;
/* Skip everything upto the "---" marker
* No need to parse the lines "Only in <dir>", and "diff <args>"
*/
do {
/* Extract the filename used before the patch was generated */
new_filename = extract_filename(patch_line, patch_level, "--- ");
// was old_filename above
patch_line = xmalloc_fgetline(patch_file);
if (!patch_line) goto quit;
} while (!new_filename);
free(new_filename); // "source" filename is irrelevant
new_filename = extract_filename(patch_line, patch_level, "+++ ");
if (!new_filename) {
bb_error_msg_and_die("invalid patch");
}
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/* Get access rights from the file to be patched */
if (stat(new_filename, &saved_stat) != 0) {
char *slash = strrchr(new_filename, '/');
if (slash) {
/* Create leading directories */
*slash = '\0';
bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
*slash = '/';
}
backup_filename = NULL;
src_stream = NULL;
saved_stat.st_mode = 0644;
} else {
backup_filename = xasprintf("%s.orig", new_filename);
xrename(new_filename, backup_filename);
src_stream = xfopen(backup_filename, "r");
}
dst_stream = xfopen(new_filename, "w");
fchmod(fileno(dst_stream), saved_stat.st_mode);
printf("patching file %s\n", new_filename);
/* Handle all hunks for this file */
patch_line = xmalloc_fgets(patch_file);
while (patch_line) {
unsigned count;
unsigned src_beg_line;
unsigned hunk_offset_start;
unsigned src_last_line = 1;
unsigned dst_last_line = 1;
if ((sscanf(patch_line, "@@ -%d,%d +%d,%d", &src_beg_line, &src_last_line, &dst_beg_line, &dst_last_line) < 3)
&& (sscanf(patch_line, "@@ -%d +%d,%d", &src_beg_line, &dst_beg_line, &dst_last_line) < 2)
) {
/* No more hunks for this file */
break;
}
if (plus != '+') {
/* reverse patch */
unsigned tmp = src_last_line;
src_last_line = dst_last_line;
dst_last_line = tmp;
tmp = src_beg_line;
src_beg_line = dst_beg_line;
dst_beg_line = tmp;
}
hunk_count++;
if (src_beg_line && dst_beg_line) {
/* Copy unmodified lines upto start of hunk */
/* src_beg_line will be 0 if it's a new file */
count = src_beg_line - src_cur_line;
if (copy_lines(src_stream, dst_stream, count)) {
bb_error_msg_and_die("bad src file");
}
src_cur_line += count;
dst_cur_line += count;
copy_trailing_lines_flag = 1;
}
src_last_line += hunk_offset_start = src_cur_line;
dst_last_line += dst_cur_line;
while (1) {
free(patch_line);
patch_line = xmalloc_fgets(patch_file);
if (patch_line == NULL)
break; /* EOF */
if ((*patch_line != '-') && (*patch_line != '+')
&& (*patch_line != ' ')
) {
break; /* End of hunk */
}
if (*patch_line != plus) { /* '-' or ' ' */
char *src_line = NULL;
if (src_cur_line == src_last_line)
break;
if (src_stream) {
src_line = xmalloc_fgets(src_stream);
if (src_line) {
int diff = strcmp(src_line, patch_line + 1);
src_cur_line++;
free(src_line);
if (diff)
src_line = NULL;
}
}
if (!src_line) {
bb_error_msg("hunk #%u FAILED at %u", hunk_count, hunk_offset_start);
bad_hunk_count++;
break;
}
if (*patch_line != ' ') { /* '-' */
continue;
}
}
if (dst_cur_line == dst_last_line)
break;
fputs(patch_line + 1, dst_stream);
dst_cur_line++;
} /* end of while loop handling one hunk */
} /* end of while loop handling one file */
/* Cleanup last patched file */
if (copy_trailing_lines_flag) {
copy_lines(src_stream, dst_stream, (unsigned)(-1));
}
if (src_stream) {
fclose(src_stream);
}
fclose(dst_stream);
if (bad_hunk_count) {
ret = 1;
bb_error_msg("%u out of %u hunk FAILED", bad_hunk_count, hunk_count);
} else {
/* It worked, we can remove the backup */
if (backup_filename) {
unlink(backup_filename);
}
if ((dst_cur_line == 0) || (dst_beg_line == 0)) {
/* The new patched file is empty, remove it */
xunlink(new_filename);
// /* old_filename and new_filename may be the same file */
// unlink(old_filename);
}
}
free(backup_filename);
//free(old_filename);
free(new_filename);
} /* end of "while there are patch lines" */
quit:
/* 0 = SUCCESS
* 1 = Some hunks failed
* 2 = More serious problems (exited earlier)
*/
return ret;
}