diff options
Diffstat (limited to 'tar.c')
| -rw-r--r-- | tar.c | 513 |
1 files changed, 226 insertions, 287 deletions
@@ -68,57 +68,84 @@ static const char tar_usage[] = #endif -/* - * Tar file constants. - */ -#define TAR_BLOCK_SIZE 512 -#define TAR_NAME_SIZE 100 +/* Tar file constants */ -/* - * 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' +/* POSIX tar Header Block, from POSIX 1003.1-1990 */ +struct TarHeader +{ + /* byte offset */ + char name[100]; /* 0 */ + char mode[8]; /* 100 */ + char uid[8]; /* 108 */ + char gid[8]; /* 116 */ + char size[12]; /* 124 */ + char mtime[12]; /* 136 */ + char chksum[8]; /* 148 */ + char typeflag; /* 156 */ + char linkname[100]; /* 157 */ + char magic[6]; /* 257 */ + char version[2]; /* 263 */ + char uname[32]; /* 265 */ + char gname[32]; /* 297 */ + char devmajor[8]; /* 329 */ + char devminor[8]; /* 337 */ + char prefix[155]; /* 345 */ + /* padding 500 */ +}; +typedef struct TarHeader TarHeader; + + +/* A few useful constants */ +#define TAR_MAGIC "ustar" /* ustar and a null */ +#define TAR_VERSION "00" /* 00 and no null */ +#define TAR_MAGIC_LEN 6 +#define TAR_VERSION_LEN 2 +#define TAR_NAME_LEN 100 +#define TAR_BLOCK_SIZE 512 + +/* A nice enum with all the possible tar file content types */ +enum TarFileType +{ + REGTYPE = '0', /* regular file */ + REGTYPE0 = '\0', /* regular file (ancient bug compat)*/ + LNKTYPE = '1', /* hard link */ + SYMTYPE = '2', /* symbolic link */ + CHRTYPE = '3', /* character special */ + BLKTYPE = '4', /* block special */ + DIRTYPE = '5', /* directory */ + FIFOTYPE = '6', /* FIFO special */ + CONTTYPE = '7', /* reserved */ +}; +typedef enum TarFileType TarFileType; + +/* This struct ignores magic, non-numeric user name, + * non-numeric group name, and the checksum, since + * these are all ignored by BusyBox tar. */ +struct TarInfo +{ + int tarFd; /* An open file descriptor for reading from the tarball */ + char * name; /* File name */ + mode_t mode; /* Unix mode, including device bits. */ + uid_t uid; /* Numeric UID */ + gid_t gid; /* Numeric GID */ + size_t size; /* Size of file */ + time_t mtime; /* Last-modified time */ + enum TarFileType type; /* Regular, directory, link, etc */ + char * linkname; /* Name for symbolic and hard links */ + dev_t device; /* Special device for mknod() */ +}; +typedef struct TarInfo TarInfo; + +/* Static data */ +static const unsigned long TarChecksumOffset = (const unsigned long)&(((TarHeader *)0)->chksum); /* * 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; @@ -134,7 +161,6 @@ static time_t mtime; /* * Static data associated with the tar file. */ -static const char *tarName; static int tarFd; static dev_t tarDev; static ino_t tarInode; @@ -143,35 +169,25 @@ static ino_t tarInode; /* * Local procedures to restore files from a tar file. */ -static void readTarFile(int fileCount, char **fileTable); +static int readTarFile(const char* tarName, int extractFlag, int listFlag, + int tostdoutFlag, int verboseFlag); 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); - +static int parseTarHeader(struct TarHeader *rawHeader, struct TarInfo *header); static int wantFileName(const char *fileName, - - int fileCount, char **fileTable); + int argc, char **argv); #ifdef BB_FEATURE_TAR_CREATE /* * 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 void writeHeader(const char *fileName, const struct stat *statbuf); - -static void writeTarFile(int fileCount, char **fileTable); +static void writeTarFile(int argc, char **argv); static void writeTarBlock(const char *buf, int len); static int putOctal(char *cp, int len, long value); @@ -180,7 +196,13 @@ static int putOctal(char *cp, int len, long value); extern int tar_main(int argc, char **argv) { + const char *tarName=NULL; const char *options; + int listFlag = FALSE; + int extractFlag = FALSE; + int createFlag = FALSE; + int verboseFlag = FALSE; + int tostdoutFlag = FALSE; argc--; argv++; @@ -188,21 +210,7 @@ extern int tar_main(int argc, char **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. - */ + /* Parse options */ if (**argv == '-') options = (*argv++) + 1; else @@ -212,13 +220,12 @@ extern int tar_main(int argc, char **argv) for (; *options; options++) { switch (*options) { case 'f': - if (tarName != NULL) { - fprintf(stderr, "Only one 'f' option allowed\n"); - - exit(FALSE); - } + if (tarName != NULL) + fatalError( "Only one 'f' option allowed\n"); tarName = *argv++; + if (tarName == NULL) + fatalError( "Option requires an argument: No file specified\n"); argc--; break; @@ -253,9 +260,8 @@ extern int tar_main(int argc, char **argv) break; default: - fprintf(stderr, "Unknown tar flag '%c'\n" + fatalError( "Unknown tar flag '%c'\n" "Try `tar --help' for more information\n", *options); - exit(FALSE); } } @@ -265,23 +271,22 @@ extern int tar_main(int argc, char **argv) */ if (createFlag == TRUE) { #ifndef BB_FEATURE_TAR_CREATE - fprintf(stderr, - "This version of tar was not compiled with tar creation support.\n"); - exit(FALSE); + fatalError( "This version of tar was not compiled with tar creation support.\n"); #else - writeTarFile(argc, argv); + exit(writeTarFile(argc, argv)); #endif } else { - readTarFile(argc, argv); + exit(readTarFile(tarName, extractFlag, listFlag, tostdoutFlag, verboseFlag)); } - if (errorFlag == TRUE) { - fprintf(stderr, "\n"); - } - exit(!errorFlag); flagError: - fprintf(stderr, "Exactly one of 'c', 'x' or 't' must be specified\n"); - exit(FALSE); + fatalError( "Exactly one of 'c', 'x' or 't' must be specified\n"); +} + +static void +tarExtractRegularFile(TarInfo *header, int extractFlag, int listFlag, int tostdoutFlag, int verboseFlag) +{ + } @@ -289,178 +294,148 @@ extern int tar_main(int argc, char **argv) * 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) +static int readTarFile(const char* tarName, int extractFlag, int listFlag, + int tostdoutFlag, int verboseFlag) { - 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; + int status, tarFd=0; + int errorFlag=FALSE; + TarHeader rawHeader; + TarInfo header; - /* - * Open the tar file for reading. - */ - if ((tarName == NULL) || !strcmp(tarName, "-")) { + /* Open the tar file for reading. */ + if (!strcmp(tarName, "-")) tarFd = fileno(stdin); - } else + else tarFd = open(tarName, O_RDONLY); - if (tarFd < 0) { - perror(tarName); - errorFlag = TRUE; - return; + errorMsg( "Error opening '%s': %s", tarName, strerror(errno)); + return ( FALSE); } - /* - * 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; + /* Read the tar file */ + while ( (status = fullRead(tarFd, (char*)&rawHeader, TAR_BLOCK_SIZE)) == TAR_BLOCK_SIZE ) { + /* Now see if the header looks ok */ + if ( parseTarHeader(&rawHeader, &header) == FALSE ) { + close( tarFd); + if ( *(header.name) == '\0' ) { + goto endgame; + } else { + errorFlag=TRUE; + errorMsg("Bad tar header, skipping\n"); + continue; } } - - /* - * 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; + if ( *(header.name) == '\0' ) + goto endgame; + + /* If we got here, we can be certain we have a legitimate + * header to work with. So work with it. */ + switch ( header.type ) { + case REGTYPE: + case REGTYPE0: + /* If the name ends in a '/' then assume it is + * supposed to be a directory, and fall through */ + if (header.name[strlen(header.name)-1] != '/') { + tarExtractRegularFile(&header, extractFlag, listFlag, tostdoutFlag, verboseFlag); + break; + } +#if 0 + case Directory: + tarExtractDirectory( &header, extractFlag, listFlag, tostdoutFlag, verboseFlag); + break; + case HardLink: + tarExtractHardLink( &header, extractFlag, listFlag, tostdoutFlag, verboseFlag); + break; + case SymbolicLink: + tarExtractSymLink( &header, extractFlag, listFlag, tostdoutFlag, verboseFlag); + break; + case CharacterDevice: + case BlockDevice: + case FIFO: + tarExtractSpecial( &header, extractFlag, listFlag, tostdoutFlag, verboseFlag); + break; +#endif + default: + close( tarFd); + return( FALSE); } - - /* - * 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) { - close(outFd); - } + close(tarFd); + if (status > 0) { + /* Bummer - we read a partial header */ + errorMsg( "Error reading '%s': %s", tarName, strerror(errno)); + return ( FALSE); } + else + return( status); + + /* Stuff we do when we know we are done with the file */ +endgame: + close( tarFd); + if ( *(header.name) == '\0' ) { + if (errorFlag==FALSE) + return( TRUE); + } + return( FALSE); } - /* - * 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. + * 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 void -readHeader(const TarHeader * hp, int fileCount, char **fileTable) +static long getOctal(const char *cp, int size) { - int checkSum; - int cc; - int hardLink; - int softLink; - int devFileFlag; - unsigned int major; - unsigned int minor; - long size; - struct utimbuf utb; - - /* - * 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. - */ - outName = hp->name; - - if (*outName == '\0') { - for (cc = TAR_BLOCK_SIZE; cc > 0; cc--) { - if (*outName++) - return; - } + long val = 0; - eofFlag = TRUE; - - return; + for(;(size > 0) && (*cp == ' '); cp++, size--); + if ((size == 0) || !isOctal(*cp)) + return -1; + for(; (size > 0) && isOctal(*cp); size--) { + val = val * 8 + *cp++ - '0'; } + for (;(size > 0) && (*cp == ' '); cp++, size--); + if ((size > 0) && *cp) + return -1; + return val; +} - /* - * 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; +/* Parse the tar header and fill in the nice struct with the details */ +static int +parseTarHeader(struct TarHeader *rawHeader, struct TarInfo *header) +{ + long major, minor, chksum, sum; + + header->name = rawHeader->name; + header->mode = getOctal(rawHeader->mode, sizeof(rawHeader->mode)); + header->uid = getOctal(rawHeader->uid, sizeof(rawHeader->uid)); + header->gid = getOctal(rawHeader->gid, sizeof(rawHeader->gid)); + header->size = getOctal(rawHeader->size, sizeof(rawHeader->size)); + header->mtime = getOctal(rawHeader->mtime, sizeof(rawHeader->mtime)); + chksum = getOctal(rawHeader->chksum, sizeof(rawHeader->chksum)); + header->type = rawHeader->typeflag; + header->linkname = rawHeader->linkname; + header->device = MAJOR(getOctal(rawHeader->devmajor, sizeof(rawHeader->devmajor))) | + MINOR(getOctal(rawHeader->devminor, sizeof(rawHeader->devminor))); + + /* Check the checksum */ + sum = ' ' * sizeof(rawHeader->chksum); + for ( i = TarChecksumOffset; i > 0; i-- ) + sum += *s++; + s += sizeof(h->chksum); + for ( i = (512 - TarChecksumOffset - sizeof(h->chksum)); i > 0; i-- ) + sum += *s++; + if (sum == checksum ) + return ( TRUE); + return( FALSE); +} - return; +#if 0 + if ((header->mode < 0) || (header->uid < 0) || + (header->gid < 0) || (header->size < 0)) { + errorMsg(stderr, "Bad tar header, skipping\n"); + return( FALSE); } badHeader = FALSE; @@ -502,7 +477,7 @@ readHeader(const TarHeader * hp, int fileCount, char **fileTable) * See if we want this file to be restored. * If not, then set up to skip it. */ - if (wantFileName(outName, fileCount, fileTable) == FALSE) { + if (wantFileName(outName, argc, argv) == FALSE) { if (!hardLink && !softLink && (S_ISREG(mode) || S_ISCHR(mode) || S_ISBLK(mode) || S_ISSOCK(mode) || S_ISFIFO(mode))) { @@ -726,7 +701,7 @@ static void readData(const char *cp, int count) * Returns TRUE if the file is selected. */ static int -wantFileName(const char *fileName, int fileCount, char **fileTable) +wantFileName(const char *fileName, int argc, char **argv) { const char *pathName; int fileLength; @@ -735,7 +710,7 @@ wantFileName(const char *fileName, int fileCount, char **fileTable) /* * If there are no files in the list, then the file is wanted. */ - if (fileCount == 0) + if (argc == 0) return TRUE; fileLength = strlen(fileName); @@ -743,8 +718,8 @@ wantFileName(const char *fileName, int fileCount, char **fileTable) /* * Check each of the test paths. */ - while (fileCount-- > 0) { - pathName = *fileTable++; + while (argc-- > 0) { + pathName = *argv++; pathLength = strlen(pathName); @@ -762,43 +737,6 @@ wantFileName(const char *fileName, int fileCount, char **fileTable) return FALSE; } -/* - * 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; -} - - - /* From here to the end of the file is the tar writing stuff. * If you do not have BB_FEATURE_TAR_CREATE defined, this will @@ -809,14 +747,14 @@ static long getOctal(const char *cp, int len) /* * Write a tar file containing the specified files. */ -static void writeTarFile(int fileCount, char **fileTable) +static void writeTarFile(int argc, char **argv) { struct stat statbuf; /* * Make sure there is at least one file specified. */ - if (fileCount <= 0) { + if (argc <= 0) { fprintf(stderr, "No files specified to be saved\n"); errorFlag = TRUE; } @@ -852,8 +790,8 @@ static void writeTarFile(int fileCount, char **fileTable) * 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); + while (errorFlag == FALSE && (argc-- > 0)) { + saveFile(*argv++, FALSE); } /* @@ -1284,3 +1222,4 @@ static int putOctal(char *cp, int len, long value) #endif /* END CODE */ +#endif |