archival/libunarchive/unarchive.c - busybox - Git at Google

 /*
  *  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 Library 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.
  */

 #include <errno.h>
 #include <fnmatch.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <utime.h>
 #include <sys/wait.h>
 #include <signal.h>
 #include "unarchive.h"
 #include "busybox.h"

 /* Extract the data postioned at src_stream to either filesystem, stdout or
  * buffer depending on the value of 'function' which is defined in libbb.h
  *
  * prefix doesnt have to be just a directory, it may prefix the filename as well.
  *
  * e.g. '/var/lib/dpkg/info/dpkg.' will extract all files to the base bath
  * '/var/lib/dpkg/info/' and all files/dirs created in that dir will have
  * 'dpkg.' as their prefix
  *
  * For this reason if prefix does point to a dir then it must end with a
  * trailing '/' or else the last dir will be assumed to be the file prefix
  */
 char *extract_archive(FILE *src_stream, FILE *out_stream, const file_header_t *file_entry,
  const int function, const char *prefix)
 {
 	FILE *dst_stream = NULL;
 	char *full_name = NULL;
 	char *buffer = NULL;
 	struct utimbuf t;

 	/* prefix doesnt have to be a proper path it may prepend
 	 * the filename as well */
 	if (prefix != NULL) {
 		/* strip leading '/' in filename to extract as prefix may not be dir */
 		/* Cant use concat_path_file here as prefix might not be a directory */
 		char *path = file_entry->name;
 		if (strncmp("./", path, 2) == 0) {
 			path += 2;
 			if (strlen(path) == 0) {
 				return(NULL);
 			}
 		}
                bb_asprintf(&full_name, "%s%s", prefix, path);
 	} else {
 		full_name = file_entry->name;
 	}
 	if (function & extract_to_stdout) {
 		if (S_ISREG(file_entry->mode)) {
 			copy_file_chunk(src_stream, out_stream, file_entry->size);
 			archive_offset += file_entry->size;
 		}
 	}
 	else if (function & extract_one_to_buffer) {
 		if (S_ISREG(file_entry->mode)) {
 			buffer = (char *) xmalloc(file_entry->size + 1);
 			fread(buffer, 1, file_entry->size, src_stream);
 			buffer[file_entry->size] = '\0';
 			archive_offset += file_entry->size;
 			return(buffer);
 		}
 	}
 	else if (function & extract_all_to_fs) {
 		struct stat oldfile;
 		int stat_res;
 		stat_res = lstat (full_name, &oldfile);
 		if (stat_res == 0) { /* The file already exists */
 			if ((function & extract_unconditional) || (oldfile.st_mtime < file_entry->mtime)) {
 				if (!S_ISDIR(oldfile.st_mode)) {
 					unlink(full_name); /* Directories might not be empty etc */
 				}
 			} else {
 				if ((function & extract_quiet) != extract_quiet) {
 					error_msg("%s not created: newer or same age file exists", file_entry->name);
 				}
 				seek_sub_file(src_stream, file_entry->size);
 				return (NULL);
 			}
 		}
 		if (function & extract_create_leading_dirs) { /* Create leading directories with default umask */
 			char *buf, *parent;
 			buf = xstrdup(full_name);
 			parent = dirname(buf);
 			if (make_directory (parent, -1, FILEUTILS_RECUR) != 0) {
 				if ((function & extract_quiet) != extract_quiet) {
 					error_msg("couldn't create leading directories");
 				}
 			}
 			free (buf);
 		}
 		switch(file_entry->mode & S_IFMT) {
 			case S_IFREG:
 				if (file_entry->link_name) { /* Found a cpio hard link */
 					if (link(file_entry->link_name, full_name) != 0) {
 						if ((function & extract_quiet) != extract_quiet) {
 							perror_msg("Cannot link from %s to '%s'",
 								file_entry->name, file_entry->link_name);
 						}
 					}
 				} else {
 					if ((dst_stream = wfopen(full_name, "w")) == NULL) {
 						seek_sub_file(src_stream, file_entry->size);
 						return NULL;
 					}
 					archive_offset += file_entry->size;
 					if (file_entry->extract_func) file_entry->extract_func(src_stream, dst_stream);
 					else copy_file_chunk(src_stream, dst_stream, file_entry->size);
 					fclose(dst_stream);
 				}
 				break;
 			case S_IFDIR:
 				if (stat_res != 0) {
 					if (mkdir(full_name, file_entry->mode) < 0) {
 						if ((function & extract_quiet) != extract_quiet) {
 							perror_msg("extract_archive: %s", full_name);
 						}
 					}
 				}
 				break;
 			case S_IFLNK:
 				if (symlink(file_entry->link_name, full_name) < 0) {
 					if ((function & extract_quiet) != extract_quiet) {
 						perror_msg("Cannot create symlink from %s to '%s'", file_entry->name, file_entry->link_name);
 					}
 					return NULL;
 				}
 				break;
 			case S_IFSOCK:
 			case S_IFBLK:
 			case S_IFCHR:
 			case S_IFIFO:
 				if (mknod(full_name, file_entry->mode, file_entry->device) == -1) {
 					if ((function & extract_quiet) != extract_quiet) {
 						perror_msg("Cannot create node %s", file_entry->name);
 					}
 					return NULL;
 				}
 				break;
 		}

 		/* Changing a symlink's properties normally changes the properties of the
 		 * file pointed to, so dont try and change the date or mode, lchown does
 		 * does the right thing, but isnt available in older versions of libc */
 		if (S_ISLNK(file_entry->mode)) {
 #if (__GLIBC__ > 2) && (__GLIBC_MINOR__ > 1)
 			lchown(full_name, file_entry->uid, file_entry->gid);
 #endif
 		} else {
 			if (function & extract_preserve_date) {
 				t.actime = file_entry->mtime;
 				t.modtime = file_entry->mtime;
 				utime(full_name, &t);
 			}
 			chmod(full_name, file_entry->mode);
 			chown(full_name, file_entry->uid, file_entry->gid);
 		}
 	} else {
 		/* If we arent extracting data we have to skip it,
 		 * if data size is 0 then then just do it anyway
 		 * (saves testing for it) */
 		seek_sub_file(src_stream, file_entry->size);
 	}

 	/* extract_list and extract_verbose_list can be used in conjunction
 	 * with one of the above four extraction functions, so do this seperately */
 	if (function & extract_verbose_list) {
 		fprintf(out_stream, "%s %d/%d %8d %s ", mode_string(file_entry->mode),
 			file_entry->uid, file_entry->gid,
 			(int) file_entry->size, time_string(file_entry->mtime));
 	}
 	if ((function & extract_list) || (function & extract_verbose_list)){
 		/* fputs doesnt add a trailing \n, so use fprintf */
 		fprintf(out_stream, "%s\n", full_name);
 	}

 	if (prefix != NULL) {
 	  free(full_name);
 	}

 	return(NULL); /* Maybe we should say if failed */
 }

 char *unarchive(FILE *src_stream, FILE *out_stream, file_header_t *(*get_headers)(FILE *),
 	const int extract_function, const char *prefix, char **include_name, char **exclude_name)
 {
 	file_header_t *file_entry;
 	int extract_flag = TRUE;
 	int i;
 	char *buffer = NULL;
 #ifdef CONFIG_FEATURE_UNARCHIVE_TAPE
 	int pid, tape_pipe[2];

 	if (pipe(tape_pipe) != 0) error_msg_and_die("Can't create pipe\n");
 	if ((pid = fork()) == -1) error_msg_and_die("Fork failed\n");
 	if (pid==0) { /* child process */
 	    close(tape_pipe[0]); /* We don't wan't to read from the pipe */
 	    copyfd(fileno(src_stream), tape_pipe[1]);
 	    close(tape_pipe[1]); /* Send EOF */
 	    exit(0);
 	    /* notreached */
 	}
 	close(tape_pipe[1]); /* Don't want to write down the pipe */
 	fclose(src_stream);
 	src_stream = fdopen(tape_pipe[0], "r");
 #endif
 	archive_offset = 0;
 	while ((file_entry = get_headers(src_stream)) != NULL) {

 		if (include_name != NULL) {
 			extract_flag = FALSE;
 			for(i = 0; include_name[i] != 0; i++) {
 				if (fnmatch(include_name[i], file_entry->name, FNM_LEADING_DIR) == 0) {
 					extract_flag = TRUE;
 					break;
 				}
 			}
 		} else {
 			extract_flag = TRUE;
 		}

 		/* If the file entry is in the exclude list dont extract it */
 		if (exclude_name != NULL) {
 			for(i = 0; exclude_name[i] != 0; i++) {
 				if (fnmatch(exclude_name[i], file_entry->name, FNM_LEADING_DIR) == 0) {
 					extract_flag = FALSE;
 					break;
 				}
 			}
 		}

 		if (extract_flag) {
 			buffer = extract_archive(src_stream, out_stream, file_entry, extract_function, prefix);
 		} else {
 			/* seek past the data entry */
 			seek_sub_file(src_stream, file_entry->size);
 		}
 		free(file_entry->name);
 		free(file_entry->link_name);
 		free(file_entry);
 	}
 #ifdef CONFIG_FEATURE_UNARCHIVE_TAPE
 	kill(pid, SIGTERM);
 	waitpid(pid, NULL, 0);
 #endif
 	return(buffer);
 }
	/*
	* 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 Library 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.
	*/

	#include <errno.h>
	#include <fnmatch.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>
	#include <utime.h>
	#include <sys/wait.h>
	#include <signal.h>
	#include "unarchive.h"
	#include "busybox.h"

	/* Extract the data postioned at src_stream to either filesystem, stdout or
	* buffer depending on the value of 'function' which is defined in libbb.h
	*
	* prefix doesnt have to be just a directory, it may prefix the filename as well.
	*
	* e.g. '/var/lib/dpkg/info/dpkg.' will extract all files to the base bath
	* '/var/lib/dpkg/info/' and all files/dirs created in that dir will have
	* 'dpkg.' as their prefix
	*
	* For this reason if prefix does point to a dir then it must end with a
	* trailing '/' or else the last dir will be assumed to be the file prefix
	*/
	char extract_archive(FILE src_stream, FILE out_stream, const file_header_t file_entry,
	const int function, const char *prefix)
	{
	FILE *dst_stream = NULL;
	char *full_name = NULL;
	char *buffer = NULL;
	struct utimbuf t;

	/* prefix doesnt have to be a proper path it may prepend
	* the filename as well */
	if (prefix != NULL) {
	/* strip leading '/' in filename to extract as prefix may not be dir */
	/* Cant use concat_path_file here as prefix might not be a directory */
	char *path = file_entry->name;
	if (strncmp("./", path, 2) == 0) {
	path += 2;
	if (strlen(path) == 0) {
	return(NULL);
	}
	}
	bb_asprintf(&full_name, "%s%s", prefix, path);
	} else {
	full_name = file_entry->name;
	}
	if (function & extract_to_stdout) {
	if (S_ISREG(file_entry->mode)) {
	copy_file_chunk(src_stream, out_stream, file_entry->size);
	archive_offset += file_entry->size;
	}
	}
	else if (function & extract_one_to_buffer) {
	if (S_ISREG(file_entry->mode)) {
	buffer = (char *) xmalloc(file_entry->size + 1);
	fread(buffer, 1, file_entry->size, src_stream);
	buffer[file_entry->size] = '\0';
	archive_offset += file_entry->size;
	return(buffer);
	}
	}
	else if (function & extract_all_to_fs) {
	struct stat oldfile;
	int stat_res;
	stat_res = lstat (full_name, &oldfile);
	if (stat_res == 0) { /* The file already exists */
	if ((function & extract_unconditional) \|\| (oldfile.st_mtime < file_entry->mtime)) {
	if (!S_ISDIR(oldfile.st_mode)) {
	unlink(full_name); /* Directories might not be empty etc */
	}
	} else {
	if ((function & extract_quiet) != extract_quiet) {
	error_msg("%s not created: newer or same age file exists", file_entry->name);
	}
	seek_sub_file(src_stream, file_entry->size);
	return (NULL);
	}
	}
	if (function & extract_create_leading_dirs) { /* Create leading directories with default umask */
	char buf, parent;
	buf = xstrdup(full_name);
	parent = dirname(buf);
	if (make_directory (parent, -1, FILEUTILS_RECUR) != 0) {
	if ((function & extract_quiet) != extract_quiet) {
	error_msg("couldn't create leading directories");
	}
	}
	free (buf);
	}
	switch(file_entry->mode & S_IFMT) {
	case S_IFREG:
	if (file_entry->link_name) { /* Found a cpio hard link */
	if (link(file_entry->link_name, full_name) != 0) {
	if ((function & extract_quiet) != extract_quiet) {
	perror_msg("Cannot link from %s to '%s'",
	file_entry->name, file_entry->link_name);
	}
	}
	} else {
	if ((dst_stream = wfopen(full_name, "w")) == NULL) {
	seek_sub_file(src_stream, file_entry->size);
	return NULL;
	}
	archive_offset += file_entry->size;
	if (file_entry->extract_func) file_entry->extract_func(src_stream, dst_stream);
	else copy_file_chunk(src_stream, dst_stream, file_entry->size);
	fclose(dst_stream);
	}
	break;
	case S_IFDIR:
	if (stat_res != 0) {
	if (mkdir(full_name, file_entry->mode) < 0) {
	if ((function & extract_quiet) != extract_quiet) {
	perror_msg("extract_archive: %s", full_name);
	}
	}
	}
	break;
	case S_IFLNK:
	if (symlink(file_entry->link_name, full_name) < 0) {
	if ((function & extract_quiet) != extract_quiet) {
	perror_msg("Cannot create symlink from %s to '%s'", file_entry->name, file_entry->link_name);
	}
	return NULL;
	}
	break;
	case S_IFSOCK:
	case S_IFBLK:
	case S_IFCHR:
	case S_IFIFO:
	if (mknod(full_name, file_entry->mode, file_entry->device) == -1) {
	if ((function & extract_quiet) != extract_quiet) {
	perror_msg("Cannot create node %s", file_entry->name);
	}
	return NULL;
	}
	break;
	}

	/* Changing a symlink's properties normally changes the properties of the
	* file pointed to, so dont try and change the date or mode, lchown does
	* does the right thing, but isnt available in older versions of libc */
	if (S_ISLNK(file_entry->mode)) {
	#if (__GLIBC__ > 2) && (__GLIBC_MINOR__ > 1)
	lchown(full_name, file_entry->uid, file_entry->gid);
	#endif
	} else {
	if (function & extract_preserve_date) {
	t.actime = file_entry->mtime;
	t.modtime = file_entry->mtime;
	utime(full_name, &t);
	}
	chmod(full_name, file_entry->mode);
	chown(full_name, file_entry->uid, file_entry->gid);
	}
	} else {
	/* If we arent extracting data we have to skip it,
	* if data size is 0 then then just do it anyway
	* (saves testing for it) */
	seek_sub_file(src_stream, file_entry->size);
	}

	/* extract_list and extract_verbose_list can be used in conjunction
	* with one of the above four extraction functions, so do this seperately */
	if (function & extract_verbose_list) {
	fprintf(out_stream, "%s %d/%d %8d %s ", mode_string(file_entry->mode),
	file_entry->uid, file_entry->gid,
	(int) file_entry->size, time_string(file_entry->mtime));
	}
	if ((function & extract_list) \|\| (function & extract_verbose_list)){
	/* fputs doesnt add a trailing \n, so use fprintf */
	fprintf(out_stream, "%s\n", full_name);
	}

	if (prefix != NULL) {
	free(full_name);
	}

	return(NULL); /* Maybe we should say if failed */
	}

	char unarchive(FILE src_stream, FILE out_stream, file_header_t (get_headers)(FILE ),
	const int extract_function, const char prefix, char include_name, char *exclude_name)
	{
	file_header_t *file_entry;
	int extract_flag = TRUE;
	int i;
	char *buffer = NULL;
	#ifdef CONFIG_FEATURE_UNARCHIVE_TAPE
	int pid, tape_pipe[2];

	if (pipe(tape_pipe) != 0) error_msg_and_die("Can't create pipe\n");
	if ((pid = fork()) == -1) error_msg_and_die("Fork failed\n");
	if (pid==0) { /* child process */
	close(tape_pipe[0]); /* We don't wan't to read from the pipe */
	copyfd(fileno(src_stream), tape_pipe[1]);
	close(tape_pipe[1]); /* Send EOF */
	exit(0);
	/* notreached */
	}
	close(tape_pipe[1]); /* Don't want to write down the pipe */
	fclose(src_stream);
	src_stream = fdopen(tape_pipe[0], "r");
	#endif
	archive_offset = 0;
	while ((file_entry = get_headers(src_stream)) != NULL) {

	if (include_name != NULL) {
	extract_flag = FALSE;
	for(i = 0; include_name[i] != 0; i++) {
	if (fnmatch(include_name[i], file_entry->name, FNM_LEADING_DIR) == 0) {
	extract_flag = TRUE;
	break;
	}
	}
	} else {
	extract_flag = TRUE;
	}

	/* If the file entry is in the exclude list dont extract it */
	if (exclude_name != NULL) {
	for(i = 0; exclude_name[i] != 0; i++) {
	if (fnmatch(exclude_name[i], file_entry->name, FNM_LEADING_DIR) == 0) {
	extract_flag = FALSE;
	break;
	}
	}
	}

	if (extract_flag) {
	buffer = extract_archive(src_stream, out_stream, file_entry, extract_function, prefix);
	} else {
	/* seek past the data entry */
	seek_sub_file(src_stream, file_entry->size);
	}
	free(file_entry->name);
	free(file_entry->link_name);
	free(file_entry);
	}
	#ifdef CONFIG_FEATURE_UNARCHIVE_TAPE
	kill(pid, SIGTERM);
	waitpid(pid, NULL, 0);
	#endif
	return(buffer);
	}