/* * Mini tar implementation for busybox based on code taken from sash. * * Copyright (c) 1999 by David I. Bell * Permission is granted to use, distribute, or modify this source, * provided that this copyright notice remains intact. * * Permission to distribute this code under the GPL has been granted. * * Modified for busybox by Erik Andersen * Adjusted to grok stdin/stdout options. * * Modified to handle device special files by Matt Porter * * * 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 * */ #include "internal.h" #include #include #include #include #include #include #include #include static const char tar_usage[] = "tar -[cxtvOf] [tarFileName] [FILE] ...\n\n" "Create, extract, or list files from a tar file\n\n" "Options:\n" "\tc=create, x=extract, t=list contents, v=verbose,\n" "\tO=extract to stdout, f=tarfile or \"-\" for stdin\n"; /* * Tar file constants. */ #define TAR_BLOCK_SIZE 512 #define TAR_NAME_SIZE 100 /* * The POSIX (and basic GNU) tar header format. * This structure is always embedded in a TAR_BLOCK_SIZE sized block * with zero padding. We only process this information minimally. */ typedef struct { char name[TAR_NAME_SIZE]; char mode[8]; char uid[8]; char gid[8]; char size[12]; char mtime[12]; char checkSum[8]; char typeFlag; char linkName[TAR_NAME_SIZE]; char magic[6]; char version[2]; char uname[32]; char gname[32]; char devMajor[8]; char devMinor[8]; char prefix[155]; } TarHeader; #define TAR_MAGIC "ustar" #define TAR_VERSION "00" #define TAR_TYPE_REGULAR '0' #define TAR_TYPE_HARD_LINK '1' #define TAR_TYPE_SOFT_LINK '2' /* * Static data. */ static int listFlag; static int extractFlag; static int createFlag; static int verboseFlag; static int tostdoutFlag; static int inHeader; // <- check me static int badHeader; static int errorFlag; static int skipFileFlag; static int warnedRoot; static int eofFlag; static long dataCc; static int outFd; static char outName[TAR_NAME_SIZE]; /* * Static data associated with the tar file. */ static const char *tarName; static int tarFd; static dev_t tarDev; static ino_t tarInode; /* * Local procedures to restore files from a tar file. */ static void readTarFile (int fileCount, char **fileTable); static void readData (const char *cp, int count); static long getOctal (const char *cp, int len); static void readHeader (const TarHeader * hp, int fileCount, char **fileTable); /* * Local procedures to save files into a tar file. */ static void saveFile (const char *fileName, int seeLinks); static void saveRegularFile (const char *fileName, const struct stat *statbuf); static void saveDirectory (const char *fileName, const struct stat *statbuf); static int wantFileName (const char *fileName, int fileCount, char **fileTable); static void writeHeader (const char *fileName, const struct stat *statbuf); static void writeTarFile (int fileCount, char **fileTable); static void writeTarBlock (const char *buf, int len); static int putOctal (char *cp, int len, long value); extern int tar_main (int argc, char **argv) { const char *options; argc--; argv++; if (argc < 1) usage( tar_usage); errorFlag = FALSE; extractFlag = FALSE; createFlag = FALSE; listFlag = FALSE; verboseFlag = FALSE; tostdoutFlag = FALSE; tarName = NULL; tarDev = 0; tarInode = 0; tarFd = -1; /* * Parse the options. */ if (**argv == '-') { options = (*argv++) + 1; argc--; for (; *options; options++) { switch (*options) { case 'f': if (tarName != NULL) { fprintf (stderr, "Only one 'f' option allowed\n"); exit (FALSE); } tarName = *argv++; argc--; break; case 't': listFlag = TRUE; break; case 'x': extractFlag = TRUE; break; case 'c': createFlag = TRUE; break; case 'v': verboseFlag = TRUE; break; case 'O': tostdoutFlag = TRUE; break; case '-': usage( tar_usage); break; default: fprintf (stderr, "Unknown tar flag '%c'\n" "Try `tar --help' for more information\n", *options); exit (FALSE); } } } /* * Validate the options. */ if (extractFlag + listFlag + createFlag != (TRUE+FALSE+FALSE)) { fprintf (stderr, "Exactly one of 'c', 'x' or 't' must be specified\n"); exit (FALSE); } /* * Do the correct type of action supplying the rest of the * command line arguments as the list of files to process. */ if (createFlag==TRUE) writeTarFile (argc, argv); else readTarFile (argc, argv); if (errorFlag==TRUE) fprintf (stderr, "\n"); exit (!errorFlag); } /* * Read a tar file and extract or list the specified files within it. * If the list is empty than all files are extracted or listed. */ static void readTarFile (int fileCount, char **fileTable) { const char *cp; int cc; int inCc; int blockSize; char buf[BUF_SIZE]; skipFileFlag = FALSE; badHeader = FALSE; warnedRoot = FALSE; eofFlag = FALSE; inHeader = TRUE; inCc = 0; dataCc = 0; outFd = -1; blockSize = sizeof (buf); cp = buf; /* * Open the tar file for reading. */ if ((tarName == NULL) || !strcmp (tarName, "-")) { tarFd = fileno(stdin); } else tarFd = open (tarName, O_RDONLY); if (tarFd < 0) { perror (tarName); errorFlag = TRUE; return; } /* * Read blocks from the file until an end of file header block * has been seen. (A real end of file from a read is an error.) */ while (eofFlag==FALSE) { /* * Read the next block of data if necessary. * This will be a large block if possible, which we will * then process in the small tar blocks. */ if (inCc <= 0) { cp = buf; inCc = fullRead (tarFd, buf, blockSize); if (inCc < 0) { perror (tarName); errorFlag = TRUE; goto done; } if (inCc == 0) { fprintf (stderr, "Unexpected end of file from \"%s\"", tarName); errorFlag = TRUE; goto done; } } /* * If we are expecting a header block then examine it. */ if (inHeader==TRUE) { readHeader ((const TarHeader *) cp, fileCount, fileTable); cp += TAR_BLOCK_SIZE; inCc -= TAR_BLOCK_SIZE; continue; } /* * We are currently handling the data for a file. * Process the minimum of the amount of data we have available * and the amount left to be processed for the file. */ cc = inCc; if (cc > dataCc) cc = dataCc; readData (cp, cc); /* * If the amount left isn't an exact multiple of the tar block * size then round it up to the next block boundary since there * is padding at the end of the file. */ if (cc % TAR_BLOCK_SIZE) cc += TAR_BLOCK_SIZE - (cc % TAR_BLOCK_SIZE); cp += cc; inCc -= cc; } done: /* * Close the tar file if needed. */ if ((tarFd >= 0) && (close (tarFd) < 0)) perror (tarName); /* * Close the output file if needed. * This is only done here on a previous error and so no * message is required on errors. */ if (tostdoutFlag == FALSE) { if (outFd >= 0) (void) close (outFd); } } /* * Examine the header block that was just read. * This can specify the information for another file, or it can mark * the end of the tar file. */ static void readHeader (const TarHeader * hp, int fileCount, char **fileTable) { int mode; int uid; int gid; int checkSum; unsigned int major; unsigned int minor; long size; time_t mtime; const char *name; int cc; int hardLink; int softLink; int devFileFlag; /* * If the block is completely empty, then this is the end of the * archive file. If the name is null, then just skip this header. */ name = hp->name; if (*name == '\0') { for (cc = TAR_BLOCK_SIZE; cc > 0; cc--) { if (*name++) return; } eofFlag = TRUE; return; } /* * There is another file in the archive to examine. * Extract the encoded information and check it. */ mode = getOctal (hp->mode, sizeof (hp->mode)); uid = getOctal (hp->uid, sizeof (hp->uid)); gid = getOctal (hp->gid, sizeof (hp->gid)); size = getOctal (hp->size, sizeof (hp->size)); mtime = getOctal (hp->mtime, sizeof (hp->mtime)); checkSum = getOctal (hp->checkSum, sizeof (hp->checkSum)); major = getOctal (hp->devMajor, sizeof (hp->devMajor)); minor = getOctal (hp->devMinor, sizeof (hp->devMinor)); if ((mode < 0) || (uid < 0) || (gid < 0) || (size < 0)) { if (badHeader==FALSE) fprintf (stderr, "Bad tar header, skipping\n"); badHeader = TRUE; return; } badHeader = FALSE; skipFileFlag = FALSE; devFileFlag = FALSE; /* * Check for the file modes. */ hardLink = ((hp->typeFlag == TAR_TYPE_HARD_LINK) || (hp->typeFlag == TAR_TYPE_HARD_LINK - '0')); softLink = ((hp->typeFlag == TAR_TYPE_SOFT_LINK) || (hp->typeFlag == TAR_TYPE_SOFT_LINK - '0')); /* * Check for a directory. */ if (name[strlen (name) - 1] == '/') mode |= S_IFDIR; /* * Check for absolute paths in the file. * If we find any, then warn the user and make them relative. */ if (*name == '/') { while (*name == '/') name++; if (warnedRoot==FALSE) { fprintf (stderr, "Absolute path detected, removing leading slashes\n"); } warnedRoot = TRUE; } /* * See if we want this file to be restored. * If not, then set up to skip it. */ if (wantFileName (name, fileCount, fileTable) == FALSE) { if ( !hardLink && !softLink && (S_ISREG (mode) || S_ISCHR (mode) || S_ISBLK (mode) || S_ISSOCK(mode) || S_ISFIFO(mode) ) ) { inHeader = (size == 0)? TRUE : FALSE; dataCc = size; } skipFileFlag = TRUE; return; } /* * This file is to be handled. * If we aren't extracting then just list information about the file. */ if (extractFlag==FALSE) { if (verboseFlag==TRUE) { printf ("%s %3d/%-d ", modeString (mode), uid, gid); if( S_ISCHR (mode) || S_ISBLK (mode) ) printf ("%4d,%4d %s ", major,minor, timeString (mtime)); else printf ("%9ld %s ", size, timeString (mtime)); } printf ("%s", name); if (hardLink) printf (" (link to \"%s\")", hp->linkName); else if (softLink) printf (" (symlink to \"%s\")", hp->linkName); else if (S_ISREG (mode) || S_ISCHR (mode) || S_ISBLK (mode) || S_ISSOCK(mode) || S_ISFIFO(mode) ) { inHeader = (size == 0)? TRUE : FALSE; dataCc = size; } printf ("\n"); return; } /* * We really want to extract the file. */ if (verboseFlag==TRUE) printf ("x %s\n", name); if (hardLink) { if (link (hp->linkName, name) < 0) perror (name); chmod(name, mode); chown(name, uid, gid); return; } if (softLink) { #ifdef S_ISLNK if (symlink (hp->linkName, name) < 0) perror (name); chmod(name, mode); chown(name, uid, gid); #else fprintf (stderr, "Cannot create symbolic links\n"); #endif return; } /* Set the umask for this process so it doesn't * screw things up. */ umask(0); /* * If the file is a directory, then just create the path. */ if (S_ISDIR (mode)) { createPath (name, mode); chmod(name, mode); chown(name, uid, gid); return; } /* * There is a file to write. * First create the path to it if necessary with default permissions. */ createPath (name, 0777); inHeader = (size == 0)? TRUE : FALSE; dataCc = size; /* * Start the output file. */ if (tostdoutFlag == TRUE) outFd = fileno(stdout); else { if ( S_ISCHR(mode) || S_ISBLK(mode) || S_ISSOCK(mode) ) { devFileFlag = TRUE; outFd = mknod (name, mode, makedev(major, minor) ); } else if (S_ISFIFO(mode) ) { devFileFlag = TRUE; outFd = mkfifo(name, mode); } else { outFd = open (name, O_WRONLY | O_CREAT | O_TRUNC, mode); } } if (outFd < 0) { perror (name); skipFileFlag = TRUE; return; } if (tostdoutFlag == FALSE) { fchmod(outFd, mode); fchown(outFd, uid, gid); } /* * If the file is empty, then that's all we need to do. */ if (size == 0 && (tostdoutFlag == FALSE) && (devFileFlag == FALSE)) { (void) close (outFd); outFd = -1; } } /* * Handle a data block of some specified size that was read. */ static void readData (const char *cp, int count) { /* * Reduce the amount of data left in this file. * If there is no more data left, then we need to read * the header again. */ dataCc -= count; if (dataCc <= 0) inHeader = TRUE; /* * If we aren't extracting files or this file is being * skipped then do nothing more. */ if (extractFlag==FALSE || skipFileFlag==TRUE) return; /* * Write the data to the output file. */ if (fullWrite (outFd, cp, count) < 0) { perror (outName); if (tostdoutFlag == FALSE) { (void) close (outFd); outFd = -1; } skipFileFlag = TRUE; return; } /* * If the write failed, close the file and disable further * writes to this file. */ if (dataCc <= 0 && tostdoutFlag == FALSE) { if (close (outFd)) perror (outName); outFd = -1; } } /* * Write a tar file containing the specified files. */ static void writeTarFile (int fileCount, char **fileTable) { struct stat statbuf; /* * Make sure there is at least one file specified. */ if (fileCount <= 0) { fprintf (stderr, "No files specified to be saved\n"); errorFlag = TRUE; } /* * Create the tar file for writing. */ if ((tarName == NULL) || !strcmp (tarName, "-")) { tostdoutFlag = TRUE; tarFd = fileno(stdout); } else tarFd = open (tarName, O_WRONLY | O_CREAT | O_TRUNC, 0666); if (tarFd < 0) { perror (tarName); errorFlag = TRUE; return; } /* * Get the device and inode of the tar file for checking later. */ if (fstat (tarFd, &statbuf) < 0) { perror (tarName); errorFlag = TRUE; goto done; } tarDev = statbuf.st_dev; tarInode = statbuf.st_ino; /* * Append each file name into the archive file. * Follow symbolic links for these top level file names. */ while (errorFlag==FALSE && (fileCount-- > 0)) { saveFile (*fileTable++, FALSE); } /* * Now write an empty block of zeroes to end the archive. */ writeTarBlock ("", 1); done: /* * Close the tar file and check for errors if it was opened. */ if ((tostdoutFlag == FALSE) && (tarFd >= 0) && (close (tarFd) < 0)) perror (tarName); } /* * Save one file into the tar file. * If the file is a directory, then this will recursively save all of * the files and directories within the directory. The seeLinks * flag indicates whether or not we want to see symbolic links as * they really are, instead of blindly following them. */ static void saveFile (const char *fileName, int seeLinks) { int status; int mode; struct stat statbuf; if (verboseFlag==TRUE) printf ("a %s\n", fileName); /* * Check that the file name will fit in the header. */ if (strlen (fileName) >= TAR_NAME_SIZE) { fprintf (stderr, "%s: File name is too long\n", fileName); return; } /* * Find out about the file. */ #ifdef S_ISLNK if (seeLinks==TRUE) status = lstat (fileName, &statbuf); else #endif status = stat (fileName, &statbuf); if (status < 0) { perror (fileName); return; } /* * Make sure we aren't trying to save our file into itself. */ if ((statbuf.st_dev == tarDev) && (statbuf.st_ino == tarInode)) { fprintf (stderr, "Skipping saving of archive file itself\n"); return; } /* * Check the type of file. */ mode = statbuf.st_mode; if (S_ISDIR (mode)) { saveDirectory (fileName, &statbuf); return; } if (S_ISREG (mode)) { saveRegularFile (fileName, &statbuf); return; } /* Some day add support for tarring these up... but not today. :) */ // if (S_ISLNK(mode) || S_ISFIFO(mode) || S_ISBLK(mode) || S_ISCHR (mode) ) { // fprintf (stderr, "%s: This version of tar can't store this type of file\n", fileName); // } /* * The file is a strange type of file, ignore it. */ fprintf (stderr, "%s: not a directory or regular file\n", fileName); } /* * Save a regular file to the tar file. */ static void saveRegularFile (const char *fileName, const struct stat *statbuf) { int sawEof; int fileFd; int cc; int dataCount; long fullDataCount; char data[TAR_BLOCK_SIZE * 16]; /* * Open the file for reading. */ fileFd = open (fileName, O_RDONLY); if (fileFd < 0) { perror (fileName); return; } /* * Write out the header for the file. */ writeHeader (fileName, statbuf); /* * Write the data blocks of the file. * We must be careful to write the amount of data that the stat * buffer indicated, even if the file has changed size. Otherwise * the tar file will be incorrect. */ fullDataCount = statbuf->st_size; sawEof = FALSE; while (fullDataCount > 0) { /* * Get the amount to write this iteration which is * the minumum of the amount left to write and the * buffer size. */ dataCount = sizeof (data); if (dataCount > fullDataCount) dataCount = (int) fullDataCount; /* * Read the data from the file if we haven't seen the * end of file yet. */ cc = 0; if (sawEof==FALSE) { cc = fullRead (fileFd, data, dataCount); if (cc < 0) { perror (fileName); (void) close (fileFd); errorFlag = TRUE; return; } /* * If the file ended too soon, complain and set * a flag so we will zero fill the rest of it. */ if (cc < dataCount) { fprintf (stderr, "%s: Short read - zero filling", fileName); sawEof = TRUE; } } /* * Zero fill the rest of the data if necessary. */ if (cc < dataCount) memset (data + cc, 0, dataCount - cc); /* * Write the buffer to the TAR file. */ writeTarBlock (data, dataCount); fullDataCount -= dataCount; } /* * Close the file. */ if ((tostdoutFlag == FALSE) && close (fileFd) < 0) fprintf (stderr, "%s: close: %s\n", fileName, strerror (errno)); } /* * Save a directory and all of its files to the tar file. */ static void saveDirectory (const char *dirName, const struct stat *statbuf) { DIR *dir; struct dirent *entry; int needSlash; char fullName[NAME_MAX]; /* * Construct the directory name as used in the tar file by appending * a slash character to it. */ strcpy (fullName, dirName); strcat (fullName, "/"); /* * Write out the header for the directory entry. */ writeHeader (fullName, statbuf); /* * Open the directory. */ dir = opendir (dirName); if (dir == NULL) { fprintf (stderr, "Cannot read directory \"%s\": %s\n", dirName, strerror (errno)); return; } /* * See if a slash is needed. */ needSlash = (*dirName && (dirName[strlen (dirName) - 1] != '/')); /* * Read all of the directory entries and check them, * except for the current and parent directory entries. */ while (errorFlag==FALSE && ((entry = readdir (dir)) != NULL)) { if ((strcmp (entry->d_name, ".") == 0) || (strcmp (entry->d_name, "..") == 0)) { continue; } /* * Build the full path name to the file. */ strcpy (fullName, dirName); if (needSlash) strcat (fullName, "/"); strcat (fullName, entry->d_name); /* * Write this file to the tar file, noticing whether or not * the file is a symbolic link. */ saveFile (fullName, TRUE); } /* * All done, close the directory. */ closedir (dir); } /* * Write a tar header for the specified file name and status. * It is assumed that the file name fits. */ static void writeHeader (const char *fileName, const struct stat *statbuf) { long checkSum; const unsigned char *cp; int len; TarHeader header; /* * Zero the header block in preparation for filling it in. */ memset ((char *) &header, 0, sizeof (header)); /* * Fill in the header. */ strcpy (header.name, fileName); strncpy (header.magic, TAR_MAGIC, sizeof (header.magic)); strncpy (header.version, TAR_VERSION, sizeof (header.version)); putOctal (header.mode, sizeof (header.mode), statbuf->st_mode & 0777); putOctal (header.uid, sizeof (header.uid), statbuf->st_uid); putOctal (header.gid, sizeof (header.gid), statbuf->st_gid); putOctal (header.size, sizeof (header.size), statbuf->st_size); putOctal (header.mtime, sizeof (header.mtime), statbuf->st_mtime); header.typeFlag = TAR_TYPE_REGULAR; /* * Calculate and store the checksum. * This is the sum of all of the bytes of the header, * with the checksum field itself treated as blanks. */ memset (header.checkSum, ' ', sizeof (header.checkSum)); cp = (const unsigned char *) &header; len = sizeof (header); checkSum = 0; while (len-- > 0) checkSum += *cp++; putOctal (header.checkSum, sizeof (header.checkSum), checkSum); /* * Write the tar header. */ writeTarBlock ((const char *) &header, sizeof (header)); } /* * Write data to one or more blocks of the tar file. * The data is always padded out to a multiple of TAR_BLOCK_SIZE. * The errorFlag static variable is set on an error. */ static void writeTarBlock (const char *buf, int len) { int partialLength; int completeLength; char fullBlock[TAR_BLOCK_SIZE]; /* * If we had a write error before, then do nothing more. */ if (errorFlag==TRUE) return; /* * Get the amount of complete and partial blocks. */ partialLength = len % TAR_BLOCK_SIZE; completeLength = len - partialLength; /* * Write all of the complete blocks. */ if ((completeLength > 0) && !fullWrite (tarFd, buf, completeLength)) { perror (tarName); errorFlag = TRUE; return; } /* * If there are no partial blocks left, we are done. */ if (partialLength == 0) return; /* * Copy the partial data into a complete block, and pad the rest * of it with zeroes. */ memcpy (fullBlock, buf + completeLength, partialLength); memset (fullBlock + partialLength, 0, TAR_BLOCK_SIZE - partialLength); /* * Write the last complete block. */ if (!fullWrite (tarFd, fullBlock, TAR_BLOCK_SIZE)) { perror (tarName); errorFlag = TRUE; } } /* * Read an octal value in a field of the specified width, with optional * spaces on both sides of the number and with an optional null character * at the end. Returns -1 on an illegal format. */ static long getOctal (const char *cp, int len) { long val; while ((len > 0) && (*cp == ' ')) { cp++; len--; } if ((len == 0) || !isOctal (*cp)) return -1; val = 0; while ((len > 0) && isOctal (*cp)) { val = val * 8 + *cp++ - '0'; len--; } while ((len > 0) && (*cp == ' ')) { cp++; len--; } if ((len > 0) && *cp) return -1; return val; } /* * Put an octal string into the specified buffer. * The number is zero and space padded and possibly null padded. * Returns TRUE if successful. */ static int putOctal (char *cp, int len, long value) { int tempLength; char *tempString; char tempBuffer[32]; /* * Create a string of the specified length with an initial space, * leading zeroes and the octal number, and a trailing null. */ tempString = tempBuffer; sprintf (tempString, " %0*lo", len - 2, value); tempLength = strlen (tempString) + 1; /* * If the string is too large, suppress the leading space. */ if (tempLength > len) { tempLength--; tempString++; } /* * If the string is still too large, suppress the trailing null. */ if (tempLength > len) tempLength--; /* * If the string is still too large, fail. */ if (tempLength > len) return FALSE; /* * Copy the string to the field. */ memcpy (cp, tempString, len); return TRUE; } /* * See if the specified file name belongs to one of the specified list * of path prefixes. An empty list implies that all files are wanted. * Returns TRUE if the file is selected. */ static int wantFileName (const char *fileName, int fileCount, char **fileTable) { const char *pathName; int fileLength; int pathLength; /* * If there are no files in the list, then the file is wanted. */ if (fileCount == 0) return TRUE; fileLength = strlen (fileName); /* * Check each of the test paths. */ while (fileCount-- > 0) { pathName = *fileTable++; pathLength = strlen (pathName); if (fileLength < pathLength) continue; if (memcmp (fileName, pathName, pathLength) != 0) continue; if ((fileLength == pathLength) || (fileName[pathLength] == '/')) { return TRUE; } } return FALSE; } /* END CODE */