2 * Mini tar implementation for busybox based on code taken from sash.
4 * Copyright (c) 1999 by David I. Bell
5 * Permission is granted to use, distribute, or modify this source,
6 * provided that this copyright notice remains intact.
8 * Permission to distribute this code under the GPL has been granted.
10 * Modified for busybox by Erik Andersen <andersee@debian.org>
11 * Adjusted to grok stdin/stdout options.
13 * Modified to handle device special files by Matt Porter
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License as published by
18 * the Free Software Foundation; either version 2 of the License, or
19 * (at your option) any later version.
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 * General Public License for more details.
26 * You should have received a copy of the GNU General Public License
27 * along with this program; if not, write to the Free Software
28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
40 #include <sys/types.h>
41 #include <sys/sysmacros.h>
44 static const char tar_usage[] =
45 "tar -[cxtvOf] [tarFileName] [FILE] ...\n\n"
46 "Create, extract, or list files from a tar file\n\n"
48 "\tc=create, x=extract, t=list contents, v=verbose,\n"
49 "\tO=extract to stdout, f=tarfile or \"-\" for stdin\n";
56 #define TAR_BLOCK_SIZE 512
57 #define TAR_NAME_SIZE 100
61 * The POSIX (and basic GNU) tar header format.
62 * This structure is always embedded in a TAR_BLOCK_SIZE sized block
63 * with zero padding. We only process this information minimally.
66 char name[TAR_NAME_SIZE];
74 char linkName[TAR_NAME_SIZE];
84 #define TAR_MAGIC "ustar"
85 #define TAR_VERSION "00"
87 #define TAR_TYPE_REGULAR '0'
88 #define TAR_TYPE_HARD_LINK '1'
89 #define TAR_TYPE_SOFT_LINK '2'
96 static int extractFlag;
97 static int createFlag;
98 static int verboseFlag;
99 static int tostdoutFlag;
101 static int inHeader; // <- check me
102 static int badHeader;
103 static int errorFlag;
104 static int skipFileFlag;
105 static int warnedRoot;
109 static char outName[TAR_NAME_SIZE];
113 * Static data associated with the tar file.
115 static const char *tarName;
118 static ino_t tarInode;
122 * Local procedures to restore files from a tar file.
124 static void readTarFile (int fileCount, char **fileTable);
125 static void readData (const char *cp, int count);
126 static long getOctal (const char *cp, int len);
128 static void readHeader (const TarHeader * hp,
129 int fileCount, char **fileTable);
133 * Local procedures to save files into a tar file.
135 static void saveFile (const char *fileName, int seeLinks);
137 static void saveRegularFile (const char *fileName,
138 const struct stat *statbuf);
140 static void saveDirectory (const char *fileName,
141 const struct stat *statbuf);
143 static int wantFileName (const char *fileName,
144 int fileCount, char **fileTable);
146 static void writeHeader (const char *fileName, const struct stat *statbuf);
148 static void writeTarFile (int fileCount, char **fileTable);
149 static void writeTarBlock (const char *buf, int len);
150 static int putOctal (char *cp, int len, long value);
153 extern int tar_main (int argc, char **argv)
169 tostdoutFlag = FALSE;
179 options = (*argv++) + 1;
181 for (; *options; options++) {
184 if (tarName != NULL) {
185 fprintf (stderr, "Only one 'f' option allowed\n");
220 fprintf (stderr, "Unknown tar flag '%c'\n"
221 "Try `tar --help' for more information\n",
230 * Validate the options.
232 if (extractFlag + listFlag + createFlag != (TRUE+FALSE+FALSE)) {
234 "Exactly one of 'c', 'x' or 't' must be specified\n");
240 * Do the correct type of action supplying the rest of the
241 * command line arguments as the list of files to process.
243 if (createFlag==TRUE)
244 writeTarFile (argc, argv);
246 readTarFile (argc, argv);
248 fprintf (stderr, "\n");
254 * Read a tar file and extract or list the specified files within it.
255 * If the list is empty than all files are extracted or listed.
257 static void readTarFile (int fileCount, char **fileTable)
265 skipFileFlag = FALSE;
273 blockSize = sizeof (buf);
277 * Open the tar file for reading.
279 if ((tarName == NULL) || !strcmp (tarName, "-")) {
280 tarFd = fileno(stdin);
282 tarFd = open (tarName, O_RDONLY);
291 * Read blocks from the file until an end of file header block
292 * has been seen. (A real end of file from a read is an error.)
294 while (eofFlag==FALSE) {
296 * Read the next block of data if necessary.
297 * This will be a large block if possible, which we will
298 * then process in the small tar blocks.
302 inCc = fullRead (tarFd, buf, blockSize);
312 "Unexpected end of file from \"%s\"", tarName);
319 * If we are expecting a header block then examine it.
321 if (inHeader==TRUE) {
322 readHeader ((const TarHeader *) cp, fileCount, fileTable);
324 cp += TAR_BLOCK_SIZE;
325 inCc -= TAR_BLOCK_SIZE;
331 * We are currently handling the data for a file.
332 * Process the minimum of the amount of data we have available
333 * and the amount left to be processed for the file.
343 * If the amount left isn't an exact multiple of the tar block
344 * size then round it up to the next block boundary since there
345 * is padding at the end of the file.
347 if (cc % TAR_BLOCK_SIZE)
348 cc += TAR_BLOCK_SIZE - (cc % TAR_BLOCK_SIZE);
356 * Close the tar file if needed.
358 if ((tarFd >= 0) && (close (tarFd) < 0))
362 * Close the output file if needed.
363 * This is only done here on a previous error and so no
364 * message is required on errors.
366 if (tostdoutFlag == FALSE) {
368 (void) close (outFd);
374 * Examine the header block that was just read.
375 * This can specify the information for another file, or it can mark
376 * the end of the tar file.
379 readHeader (const TarHeader * hp, int fileCount, char **fileTable)
396 * If the block is completely empty, then this is the end of the
397 * archive file. If the name is null, then just skip this header.
402 for (cc = TAR_BLOCK_SIZE; cc > 0; cc--) {
413 * There is another file in the archive to examine.
414 * Extract the encoded information and check it.
416 mode = getOctal (hp->mode, sizeof (hp->mode));
417 uid = getOctal (hp->uid, sizeof (hp->uid));
418 gid = getOctal (hp->gid, sizeof (hp->gid));
419 size = getOctal (hp->size, sizeof (hp->size));
420 mtime = getOctal (hp->mtime, sizeof (hp->mtime));
421 checkSum = getOctal (hp->checkSum, sizeof (hp->checkSum));
422 major = getOctal (hp->devMajor, sizeof (hp->devMajor));
423 minor = getOctal (hp->devMinor, sizeof (hp->devMinor));
425 if ((mode < 0) || (uid < 0) || (gid < 0) || (size < 0)) {
426 if (badHeader==FALSE)
427 fprintf (stderr, "Bad tar header, skipping\n");
435 skipFileFlag = FALSE;
439 * Check for the file modes.
441 hardLink = ((hp->typeFlag == TAR_TYPE_HARD_LINK) ||
442 (hp->typeFlag == TAR_TYPE_HARD_LINK - '0'));
444 softLink = ((hp->typeFlag == TAR_TYPE_SOFT_LINK) ||
445 (hp->typeFlag == TAR_TYPE_SOFT_LINK - '0'));
448 * Check for a directory.
450 if (name[strlen (name) - 1] == '/')
454 * Check for absolute paths in the file.
455 * If we find any, then warn the user and make them relative.
461 if (warnedRoot==FALSE) {
463 "Absolute path detected, removing leading slashes\n");
470 * See if we want this file to be restored.
471 * If not, then set up to skip it.
473 if (wantFileName (name, fileCount, fileTable) == FALSE) {
474 if ( !hardLink && !softLink && (S_ISREG (mode) || S_ISCHR (mode)
475 || S_ISBLK (mode) || S_ISSOCK(mode) || S_ISFIFO(mode) ) ) {
476 inHeader = (size == 0)? TRUE : FALSE;
486 * This file is to be handled.
487 * If we aren't extracting then just list information about the file.
489 if (extractFlag==FALSE) {
490 if (verboseFlag==TRUE) {
491 printf ("%s %3d/%-d %9ld %s %s", modeString (mode),
492 uid, gid, size, timeString (mtime), name);
497 printf (" (link to \"%s\")", hp->linkName);
499 printf (" (symlink to \"%s\")", hp->linkName);
500 else if (S_ISREG (mode) || S_ISCHR (mode) || S_ISBLK (mode) ||
501 S_ISSOCK(mode) || S_ISFIFO(mode) ) {
502 inHeader = (size == 0)? TRUE : FALSE;
512 * We really want to extract the file.
514 if (verboseFlag==TRUE)
515 printf ("x %s\n", name);
518 if (link (hp->linkName, name) < 0)
526 if (symlink (hp->linkName, name) < 0)
529 fprintf (stderr, "Cannot create symbolic links\n");
535 * If the file is a directory, then just create the path.
537 if (S_ISDIR (mode)) {
538 createPath (name, mode);
544 * There is a file to write.
545 * First create the path to it if necessary with a default permission.
547 createPath (name, 0777);
549 inHeader = (size == 0)? TRUE : FALSE;
553 * Start the output file.
555 if (tostdoutFlag == TRUE)
556 outFd = fileno(stdout);
558 if ( S_ISCHR(mode) || S_ISBLK(mode) || S_ISSOCK(mode) ) {
560 outFd = mknod (name, mode, makedev(major, minor) );
562 else if (S_ISFIFO(mode) ) {
564 outFd = mkfifo(name, mode);
566 outFd = open (name, O_WRONLY | O_CREAT | O_TRUNC, mode);
577 * If the file is empty, then that's all we need to do.
579 if (size == 0 && (tostdoutFlag == FALSE) && (devFileFlag == FALSE)) {
580 (void) close (outFd);
587 * Handle a data block of some specified size that was read.
589 static void readData (const char *cp, int count)
592 * Reduce the amount of data left in this file.
593 * If there is no more data left, then we need to read
602 * If we aren't extracting files or this file is being
603 * skipped then do nothing more.
605 if (extractFlag==FALSE || skipFileFlag==TRUE)
609 * Write the data to the output file.
611 if (fullWrite (outFd, cp, count) < 0) {
613 if (tostdoutFlag == FALSE) {
614 (void) close (outFd);
622 * If the write failed, close the file and disable further
623 * writes to this file.
625 if (dataCc <= 0 && tostdoutFlag == FALSE) {
635 * Write a tar file containing the specified files.
637 static void writeTarFile (int fileCount, char **fileTable)
642 * Make sure there is at least one file specified.
644 if (fileCount <= 0) {
645 fprintf (stderr, "No files specified to be saved\n");
650 * Create the tar file for writing.
652 if ((tarName == NULL) || !strcmp (tarName, "-")) {
654 tarFd = fileno(stdout);
656 tarFd = open (tarName, O_WRONLY | O_CREAT | O_TRUNC, 0666);
665 * Get the device and inode of the tar file for checking later.
667 if (fstat (tarFd, &statbuf) < 0) {
673 tarDev = statbuf.st_dev;
674 tarInode = statbuf.st_ino;
677 * Append each file name into the archive file.
678 * Follow symbolic links for these top level file names.
680 while (errorFlag==FALSE && (fileCount-- > 0)) {
681 saveFile (*fileTable++, FALSE);
685 * Now write an empty block of zeroes to end the archive.
687 writeTarBlock ("", 1);
692 * Close the tar file and check for errors if it was opened.
694 if ((tostdoutFlag == FALSE) && (tarFd >= 0) && (close (tarFd) < 0))
700 * Save one file into the tar file.
701 * If the file is a directory, then this will recursively save all of
702 * the files and directories within the directory. The seeLinks
703 * flag indicates whether or not we want to see symbolic links as
704 * they really are, instead of blindly following them.
706 static void saveFile (const char *fileName, int seeLinks)
712 if (verboseFlag==TRUE)
713 printf ("a %s\n", fileName);
716 * Check that the file name will fit in the header.
718 if (strlen (fileName) >= TAR_NAME_SIZE) {
719 fprintf (stderr, "%s: File name is too long\n", fileName);
725 * Find out about the file.
729 status = lstat (fileName, &statbuf);
732 status = stat (fileName, &statbuf);
741 * Make sure we aren't trying to save our file into itself.
743 if ((statbuf.st_dev == tarDev) && (statbuf.st_ino == tarInode)) {
744 fprintf (stderr, "Skipping saving of archive file itself\n");
750 * Check the type of file.
752 mode = statbuf.st_mode;
754 if (S_ISDIR (mode)) {
755 saveDirectory (fileName, &statbuf);
759 if (S_ISREG (mode)) {
760 saveRegularFile (fileName, &statbuf);
765 /* Some day add support for tarring these up... but not today. :) */
766 // if (S_ISLNK(mode) || S_ISFIFO(mode) || S_ISBLK(mode) || S_ISCHR (mode) ) {
767 // fprintf (stderr, "%s: This version of tar can't store this type of file\n", fileName);
771 * The file is a strange type of file, ignore it.
773 fprintf (stderr, "%s: not a directory or regular file\n", fileName);
778 * Save a regular file to the tar file.
781 saveRegularFile (const char *fileName, const struct stat *statbuf)
788 char data[TAR_BLOCK_SIZE * 16];
791 * Open the file for reading.
793 fileFd = open (fileName, O_RDONLY);
802 * Write out the header for the file.
804 writeHeader (fileName, statbuf);
807 * Write the data blocks of the file.
808 * We must be careful to write the amount of data that the stat
809 * buffer indicated, even if the file has changed size. Otherwise
810 * the tar file will be incorrect.
812 fullDataCount = statbuf->st_size;
815 while (fullDataCount > 0) {
817 * Get the amount to write this iteration which is
818 * the minumum of the amount left to write and the
821 dataCount = sizeof (data);
823 if (dataCount > fullDataCount)
824 dataCount = (int) fullDataCount;
827 * Read the data from the file if we haven't seen the
833 cc = fullRead (fileFd, data, dataCount);
838 (void) close (fileFd);
845 * If the file ended too soon, complain and set
846 * a flag so we will zero fill the rest of it.
848 if (cc < dataCount) {
850 "%s: Short read - zero filling", fileName);
857 * Zero fill the rest of the data if necessary.
860 memset (data + cc, 0, dataCount - cc);
863 * Write the buffer to the TAR file.
865 writeTarBlock (data, dataCount);
867 fullDataCount -= dataCount;
873 if ((tostdoutFlag == FALSE) && close (fileFd) < 0)
874 fprintf (stderr, "%s: close: %s\n", fileName, strerror (errno));
879 * Save a directory and all of its files to the tar file.
881 static void saveDirectory (const char *dirName, const struct stat *statbuf)
884 struct dirent *entry;
886 char fullName[NAME_MAX];
889 * Construct the directory name as used in the tar file by appending
890 * a slash character to it.
892 strcpy (fullName, dirName);
893 strcat (fullName, "/");
896 * Write out the header for the directory entry.
898 writeHeader (fullName, statbuf);
901 * Open the directory.
903 dir = opendir (dirName);
906 fprintf (stderr, "Cannot read directory \"%s\": %s\n",
907 dirName, strerror (errno));
913 * See if a slash is needed.
915 needSlash = (*dirName && (dirName[strlen (dirName) - 1] != '/'));
918 * Read all of the directory entries and check them,
919 * except for the current and parent directory entries.
921 while (errorFlag==FALSE && ((entry = readdir (dir)) != NULL)) {
922 if ((strcmp (entry->d_name, ".") == 0) ||
923 (strcmp (entry->d_name, "..") == 0)) {
928 * Build the full path name to the file.
930 strcpy (fullName, dirName);
933 strcat (fullName, "/");
935 strcat (fullName, entry->d_name);
938 * Write this file to the tar file, noticing whether or not
939 * the file is a symbolic link.
941 saveFile (fullName, TRUE);
945 * All done, close the directory.
952 * Write a tar header for the specified file name and status.
953 * It is assumed that the file name fits.
955 static void writeHeader (const char *fileName, const struct stat *statbuf)
958 const unsigned char *cp;
963 * Zero the header block in preparation for filling it in.
965 memset ((char *) &header, 0, sizeof (header));
968 * Fill in the header.
970 strcpy (header.name, fileName);
972 strncpy (header.magic, TAR_MAGIC, sizeof (header.magic));
973 strncpy (header.version, TAR_VERSION, sizeof (header.version));
975 putOctal (header.mode, sizeof (header.mode), statbuf->st_mode & 0777);
976 putOctal (header.uid, sizeof (header.uid), statbuf->st_uid);
977 putOctal (header.gid, sizeof (header.gid), statbuf->st_gid);
978 putOctal (header.size, sizeof (header.size), statbuf->st_size);
979 putOctal (header.mtime, sizeof (header.mtime), statbuf->st_mtime);
981 header.typeFlag = TAR_TYPE_REGULAR;
984 * Calculate and store the checksum.
985 * This is the sum of all of the bytes of the header,
986 * with the checksum field itself treated as blanks.
988 memset (header.checkSum, ' ', sizeof (header.checkSum));
990 cp = (const unsigned char *) &header;
991 len = sizeof (header);
997 putOctal (header.checkSum, sizeof (header.checkSum), checkSum);
1000 * Write the tar header.
1002 writeTarBlock ((const char *) &header, sizeof (header));
1007 * Write data to one or more blocks of the tar file.
1008 * The data is always padded out to a multiple of TAR_BLOCK_SIZE.
1009 * The errorFlag static variable is set on an error.
1011 static void writeTarBlock (const char *buf, int len)
1015 char fullBlock[TAR_BLOCK_SIZE];
1018 * If we had a write error before, then do nothing more.
1020 if (errorFlag==TRUE)
1024 * Get the amount of complete and partial blocks.
1026 partialLength = len % TAR_BLOCK_SIZE;
1027 completeLength = len - partialLength;
1030 * Write all of the complete blocks.
1032 if ((completeLength > 0) && !fullWrite (tarFd, buf, completeLength)) {
1041 * If there are no partial blocks left, we are done.
1043 if (partialLength == 0)
1047 * Copy the partial data into a complete block, and pad the rest
1048 * of it with zeroes.
1050 memcpy (fullBlock, buf + completeLength, partialLength);
1051 memset (fullBlock + partialLength, 0, TAR_BLOCK_SIZE - partialLength);
1054 * Write the last complete block.
1056 if (!fullWrite (tarFd, fullBlock, TAR_BLOCK_SIZE)) {
1065 * Read an octal value in a field of the specified width, with optional
1066 * spaces on both sides of the number and with an optional null character
1067 * at the end. Returns -1 on an illegal format.
1069 static long getOctal (const char *cp, int len)
1073 while ((len > 0) && (*cp == ' ')) {
1078 if ((len == 0) || !isOctal (*cp))
1083 while ((len > 0) && isOctal (*cp)) {
1084 val = val * 8 + *cp++ - '0';
1088 while ((len > 0) && (*cp == ' ')) {
1093 if ((len > 0) && *cp)
1101 * Put an octal string into the specified buffer.
1102 * The number is zero and space padded and possibly null padded.
1103 * Returns TRUE if successful.
1105 static int putOctal (char *cp, int len, long value)
1109 char tempBuffer[32];
1112 * Create a string of the specified length with an initial space,
1113 * leading zeroes and the octal number, and a trailing null.
1115 tempString = tempBuffer;
1117 sprintf (tempString, " %0*lo", len - 2, value);
1119 tempLength = strlen (tempString) + 1;
1122 * If the string is too large, suppress the leading space.
1124 if (tempLength > len) {
1130 * If the string is still too large, suppress the trailing null.
1132 if (tempLength > len)
1136 * If the string is still too large, fail.
1138 if (tempLength > len)
1142 * Copy the string to the field.
1144 memcpy (cp, tempString, len);
1151 * See if the specified file name belongs to one of the specified list
1152 * of path prefixes. An empty list implies that all files are wanted.
1153 * Returns TRUE if the file is selected.
1156 wantFileName (const char *fileName, int fileCount, char **fileTable)
1158 const char *pathName;
1163 * If there are no files in the list, then the file is wanted.
1168 fileLength = strlen (fileName);
1171 * Check each of the test paths.
1173 while (fileCount-- > 0) {
1174 pathName = *fileTable++;
1176 pathLength = strlen (pathName);
1178 if (fileLength < pathLength)
1181 if (memcmp (fileName, pathName, pathLength) != 0)
1184 if ((fileLength == pathLength) || (fileName[pathLength] == '/')) {