busybox/editors/patch.c

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/* vi: set sw=4 ts=4: */
/*
* busybox patch applet to handle the unified diff format.
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* 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 <getopt.h>
#include "libbb.h"
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static unsigned int copy_lines(FILE *src_stream, FILE *dest_stream, const unsigned int lines_count)
{
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unsigned int i = 0;
while (src_stream && (i < lines_count)) {
char *line;
line = xmalloc_fgets(src_stream);
if (line == NULL) {
break;
}
if (fputs(line, dest_stream) == EOF) {
bb_perror_msg_and_die("error writing to new file");
}
free(line);
i++;
}
return i;
}
/* 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
*/
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static char *extract_filename(char *line, int patch_level)
{
char *temp, *filename_start_ptr = line + 4;
int i;
/* Terminate string at end of source filename */
temp = strchrnul(filename_start_ptr, '\t');
*temp = '\0';
/* Skip over (patch_level) number of leading directories */
if (patch_level == -1)
patch_level = INT_MAX;
for (i = 0; i < patch_level; i++) {
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temp = strchr(filename_start_ptr, '/');
if (!temp)
break;
filename_start_ptr = temp + 1;
}
return xstrdup(filename_start_ptr);
}
static int file_doesnt_exist(const char *filename)
{
struct stat statbuf;
return stat(filename, &statbuf);
}
int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int patch_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
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int patch_level = -1;
char *patch_line;
int ret;
FILE *patch_file = NULL;
{
char *p, *i;
ret = getopt32(argv, "p:i:", &p, &i);
if (ret & 1)
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patch_level = xatol_range(p, -1, USHRT_MAX);
if (ret & 2) {
patch_file = xfopen(i, "r");
} else {
patch_file = stdin;
}
ret = 0;
}
patch_line = xmalloc_getline(patch_file);
while (patch_line) {
FILE *src_stream;
FILE *dst_stream;
char *original_filename;
char *new_filename;
char *backup_filename;
unsigned int src_cur_line = 1;
unsigned int dest_cur_line = 0;
unsigned int dest_beg_line;
unsigned int bad_hunk_count = 0;
unsigned int hunk_count = 0;
char copy_trailing_lines_flag = 0;
/* Skip everything upto the "---" marker
* No need to parse the lines "Only in <dir>", and "diff <args>"
*/
while (patch_line && strncmp(patch_line, "--- ", 4) != 0) {
free(patch_line);
patch_line = xmalloc_getline(patch_file);
}
/* FIXME: patch_line NULL check?? */
/* Extract the filename used before the patch was generated */
original_filename = extract_filename(patch_line, patch_level);
free(patch_line);
patch_line = xmalloc_getline(patch_file);
/* FIXME: NULL check?? */
if (strncmp(patch_line, "+++ ", 4) != 0) {
ret = 2;
bb_error_msg("invalid patch");
continue;
}
new_filename = extract_filename(patch_line, patch_level);
free(patch_line);
if (file_doesnt_exist(new_filename)) {
char *line_ptr;
/* Create leading directories */
line_ptr = strrchr(new_filename, '/');
if (line_ptr) {
*line_ptr = '\0';
bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
*line_ptr = '/';
}
dst_stream = xfopen(new_filename, "w+");
backup_filename = NULL;
} else {
backup_filename = xmalloc(strlen(new_filename) + 6);
strcpy(backup_filename, new_filename);
strcat(backup_filename, ".orig");
xrename(new_filename, backup_filename);
dst_stream = xfopen(new_filename, "w");
}
if ((backup_filename == NULL) || file_doesnt_exist(original_filename)) {
src_stream = NULL;
} else {
if (strcmp(original_filename, new_filename) == 0) {
src_stream = xfopen(backup_filename, "r");
} else {
src_stream = xfopen(original_filename, "r");
}
}
printf("patching file %s\n", new_filename);
/* Handle each hunk */
patch_line = xmalloc_fgets(patch_file);
while (patch_line) {
unsigned int count;
unsigned int src_beg_line;
unsigned int unused;
unsigned int hunk_offset_start = 0;
int hunk_error = 0;
/* This bit should be improved */
if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4) &&
(sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3) &&
(sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)) {
/* No more hunks for this file */
break;
}
free(patch_line);
hunk_count++;
if (src_beg_line && dest_beg_line) {
/* Copy unmodified lines upto start of hunk */
/* src_beg_line will be 0 if its a new file */
count = src_beg_line - src_cur_line;
if (copy_lines(src_stream, dst_stream, count) != count) {
bb_error_msg_and_die("bad src file");
}
src_cur_line += count;
dest_cur_line += count;
copy_trailing_lines_flag = 1;
}
hunk_offset_start = src_cur_line;
while ((patch_line = xmalloc_fgets(patch_file)) != NULL) {
if ((*patch_line == '-') || (*patch_line == ' ')) {
char *src_line = NULL;
if (src_stream) {
src_line = xmalloc_fgets(src_stream);
if (!src_line) {
hunk_error++;
break;
} else {
src_cur_line++;
}
if (strcmp(src_line, patch_line + 1) != 0) {
bb_error_msg("hunk #%d FAILED at %d", hunk_count, hunk_offset_start);
hunk_error++;
free(patch_line);
/* Probably need to find next hunk, etc... */
/* but for now we just bail out */
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patch_line = NULL;
break;
}
free(src_line);
}
if (*patch_line == ' ') {
fputs(patch_line + 1, dst_stream);
dest_cur_line++;
}
} else if (*patch_line == '+') {
fputs(patch_line + 1, dst_stream);
dest_cur_line++;
} else {
break;
}
free(patch_line);
}
if (hunk_error) {
bad_hunk_count++;
}
}
/* Cleanup last patched file */
if (copy_trailing_lines_flag) {
copy_lines(src_stream, dst_stream, -1);
}
if (src_stream) {
fclose(src_stream);
}
if (dst_stream) {
fclose(dst_stream);
}
if (bad_hunk_count) {
if (!ret) {
ret = 1;
}
bb_error_msg("%d out of %d hunk FAILED", bad_hunk_count, hunk_count);
} else {
/* It worked, we can remove the backup */
if (backup_filename) {
unlink(backup_filename);
}
if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
/* The new patched file is empty, remove it */
xunlink(new_filename);
if (strcmp(new_filename, original_filename) != 0)
xunlink(original_filename);
}
}
}
/* 0 = SUCCESS
* 1 = Some hunks failed
* 2 = More serious problems
*/
return ret;
}