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Diffstat (limited to 'bin/pax/ar_io.c')
| -rw-r--r-- | bin/pax/ar_io.c | 1289 |
1 files changed, 1289 insertions, 0 deletions
diff --git a/bin/pax/ar_io.c b/bin/pax/ar_io.c new file mode 100644 index 000000000000..0946a8884c5f --- /dev/null +++ b/bin/pax/ar_io.c @@ -0,0 +1,1289 @@ +/*- + * Copyright (c) 1992 Keith Muller. + * Copyright (c) 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Keith Muller of the University of California, San Diego. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef lint +#if 0 +static char sccsid[] = "@(#)ar_io.c 8.2 (Berkeley) 4/18/94"; +#endif +#endif /* not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/types.h> +#include <sys/ioctl.h> +#include <sys/mtio.h> +#include <sys/stat.h> +#include <sys/wait.h> +#include <err.h> +#include <errno.h> +#include <fcntl.h> +#include <signal.h> +#include <stdint.h> +#include <stdio.h> +#include <string.h> +#include <stdlib.h> +#include <unistd.h> +#include "pax.h" +#include "options.h" +#include "extern.h" + +/* + * Routines which deal directly with the archive I/O device/file. + */ + +#define DMOD 0666 /* default mode of created archives */ +#define EXT_MODE O_RDONLY /* open mode for list/extract */ +#define AR_MODE (O_WRONLY | O_CREAT | O_TRUNC) /* mode for archive */ +#define APP_MODE O_RDWR /* mode for append */ + +static char none[] = "<NONE>"; /* pseudo name for no file */ +static char stdo[] = "<STDOUT>"; /* pseudo name for stdout */ +static char stdn[] = "<STDIN>"; /* pseudo name for stdin */ +static int arfd = -1; /* archive file descriptor */ +static int artyp = ISREG; /* archive type: file/FIFO/tape */ +static int arvol = 1; /* archive volume number */ +static int lstrval = -1; /* return value from last i/o */ +static int io_ok; /* i/o worked on volume after resync */ +static int did_io; /* did i/o ever occur on volume? */ +static int done; /* set via tty termination */ +static struct stat arsb; /* stat of archive device at open */ +static int invld_rec; /* tape has out of spec record size */ +static int wr_trail = 1; /* trailer was rewritten in append */ +static int can_unlnk = 0; /* do we unlink null archives? */ +const char *arcname; /* printable name of archive */ +const char *gzip_program; /* name of gzip program */ +static pid_t zpid = -1; /* pid of child process */ + +static int get_phys(void); +extern sigset_t s_mask; +static void ar_start_gzip(int, const char *, int); + +/* + * ar_open() + * Opens the next archive volume. Determines the type of the device and + * sets up block sizes as required by the archive device and the format. + * Note: we may be called with name == NULL on the first open only. + * Return: + * -1 on failure, 0 otherwise + */ + +int +ar_open(const char *name) +{ + struct mtget mb; + + if (arfd != -1) + (void)close(arfd); + arfd = -1; + can_unlnk = did_io = io_ok = invld_rec = 0; + artyp = ISREG; + flcnt = 0; + + /* + * open based on overall operation mode + */ + switch (act) { + case LIST: + case EXTRACT: + if (name == NULL) { + arfd = STDIN_FILENO; + arcname = stdn; + } else if ((arfd = open(name, EXT_MODE, DMOD)) < 0) + syswarn(0, errno, "Failed open to read on %s", name); + if (arfd != -1 && gzip_program != NULL) + ar_start_gzip(arfd, gzip_program, 0); + break; + case ARCHIVE: + if (name == NULL) { + arfd = STDOUT_FILENO; + arcname = stdo; + } else if ((arfd = open(name, AR_MODE, DMOD)) < 0) + syswarn(0, errno, "Failed open to write on %s", name); + else + can_unlnk = 1; + if (arfd != -1 && gzip_program != NULL) + ar_start_gzip(arfd, gzip_program, 1); + break; + case APPND: + if (name == NULL) { + arfd = STDOUT_FILENO; + arcname = stdo; + } else if ((arfd = open(name, APP_MODE, DMOD)) < 0) + syswarn(0, errno, "Failed open to read/write on %s", + name); + break; + case COPY: + /* + * arfd not used in COPY mode + */ + arcname = none; + lstrval = 1; + return(0); + } + if (arfd < 0) + return(-1); + + if (chdname != NULL) + if (chdir(chdname) != 0) { + syswarn(1, errno, "Failed chdir to %s", chdname); + return(-1); + } + /* + * set up is based on device type + */ + if (fstat(arfd, &arsb) < 0) { + syswarn(0, errno, "Failed stat on %s", arcname); + (void)close(arfd); + arfd = -1; + can_unlnk = 0; + return(-1); + } + if (S_ISDIR(arsb.st_mode)) { + paxwarn(0, "Cannot write an archive on top of a directory %s", + arcname); + (void)close(arfd); + arfd = -1; + can_unlnk = 0; + return(-1); + } + + if (S_ISCHR(arsb.st_mode)) + artyp = ioctl(arfd, MTIOCGET, &mb) ? ISCHR : ISTAPE; + else if (S_ISBLK(arsb.st_mode)) + artyp = ISBLK; + else if ((lseek(arfd, (off_t)0L, SEEK_CUR) == -1) && (errno == ESPIPE)) + artyp = ISPIPE; + else + artyp = ISREG; + + /* + * make sure we beyond any doubt that we only can unlink regular files + * we created + */ + if (artyp != ISREG) + can_unlnk = 0; + /* + * if we are writing, we are done + */ + if (act == ARCHIVE) { + blksz = rdblksz = wrblksz; + lstrval = 1; + return(0); + } + + /* + * set default blksz on read. APPNDs writes rdblksz on the last volume + * On all new archive volumes, we shift to wrblksz (if the user + * specified one, otherwize we will continue to use rdblksz). We + * must to set blocksize based on what kind of device the archive is + * stored. + */ + switch(artyp) { + case ISTAPE: + /* + * Tape drives come in at least two flavors. Those that support + * variable sized records and those that have fixed sized + * records. They must be treated differently. For tape drives + * that support variable sized records, we must make large + * reads to make sure we get the entire record, otherwise we + * will just get the first part of the record (up to size we + * asked). Tapes with fixed sized records may or may not return + * multiple records in a single read. We really do not care + * what the physical record size is UNLESS we are going to + * append. (We will need the physical block size to rewrite + * the trailer). Only when we are appending do we go to the + * effort to figure out the true PHYSICAL record size. + */ + blksz = rdblksz = MAXBLK; + break; + case ISPIPE: + case ISBLK: + case ISCHR: + /* + * Blocksize is not a major issue with these devices (but must + * be kept a multiple of 512). If the user specified a write + * block size, we use that to read. Under append, we must + * always keep blksz == rdblksz. Otherwise we go ahead and use + * the device optimal blocksize as (and if) returned by stat + * and if it is within pax specs. + */ + if ((act == APPND) && wrblksz) { + blksz = rdblksz = wrblksz; + break; + } + + if ((arsb.st_blksize > 0) && (arsb.st_blksize < MAXBLK) && + ((arsb.st_blksize % BLKMULT) == 0)) + rdblksz = arsb.st_blksize; + else + rdblksz = DEVBLK; + /* + * For performance go for large reads when we can without harm + */ + if ((act == APPND) || (artyp == ISCHR)) + blksz = rdblksz; + else + blksz = MAXBLK; + break; + case ISREG: + /* + * if the user specified wrblksz works, use it. Under appends + * we must always keep blksz == rdblksz + */ + if ((act == APPND) && wrblksz && ((arsb.st_size%wrblksz)==0)){ + blksz = rdblksz = wrblksz; + break; + } + /* + * See if we can find the blocking factor from the file size + */ + for (rdblksz = MAXBLK; rdblksz > 0; rdblksz -= BLKMULT) + if ((arsb.st_size % rdblksz) == 0) + break; + /* + * When we cannot find a match, we may have a flawed archive. + */ + if (rdblksz <= 0) + rdblksz = FILEBLK; + /* + * for performance go for large reads when we can + */ + if (act == APPND) + blksz = rdblksz; + else + blksz = MAXBLK; + break; + default: + /* + * should never happen, worse case, slow... + */ + blksz = rdblksz = BLKMULT; + break; + } + lstrval = 1; + return(0); +} + +/* + * ar_close() + * closes archive device, increments volume number, and prints i/o summary + */ +void +ar_close(void) +{ + int status; + + if (arfd < 0) { + did_io = io_ok = flcnt = 0; + return; + } + + /* + * Close archive file. This may take a LONG while on tapes (we may be + * forced to wait for the rewind to complete) so tell the user what is + * going on (this avoids the user hitting control-c thinking pax is + * broken). + */ + if (vflag && (artyp == ISTAPE)) { + if (vfpart) + (void)putc('\n', listf); + (void)fprintf(listf, + "%s: Waiting for tape drive close to complete...", + argv0); + (void)fflush(listf); + } + + /* + * if nothing was written to the archive (and we created it), we remove + * it + */ + if (can_unlnk && (fstat(arfd, &arsb) == 0) && (S_ISREG(arsb.st_mode)) && + (arsb.st_size == 0)) { + (void)unlink(arcname); + can_unlnk = 0; + } + + /* + * for a quick extract/list, pax frequently exits before the child + * process is done + */ + if ((act == LIST || act == EXTRACT) && nflag && zpid > 0) + kill(zpid, SIGINT); + + (void)close(arfd); + + /* Do not exit before child to ensure data integrity */ + if (zpid > 0) + waitpid(zpid, &status, 0); + + if (vflag && (artyp == ISTAPE)) { + (void)fputs("done.\n", listf); + vfpart = 0; + (void)fflush(listf); + } + arfd = -1; + + if (!io_ok && !did_io) { + flcnt = 0; + return; + } + did_io = io_ok = 0; + + /* + * The volume number is only increased when the last device has data + * and we have already determined the archive format. + */ + if (frmt != NULL) + ++arvol; + + if (!vflag) { + flcnt = 0; + return; + } + + /* + * Print out a summary of I/O for this archive volume. + */ + if (vfpart) { + (void)putc('\n', listf); + vfpart = 0; + } + + /* + * If we have not determined the format yet, we just say how many bytes + * we have skipped over looking for a header to id. there is no way we + * could have written anything yet. + */ + if (frmt == NULL) { +# ifdef NET2_STAT + (void)fprintf(listf, "%s: unknown format, %lu bytes skipped.\n", + argv0, rdcnt); +# else + (void)fprintf(listf, "%s: unknown format, %ju bytes skipped.\n", + argv0, (uintmax_t)rdcnt); +# endif + (void)fflush(listf); + flcnt = 0; + return; + } + + if (strcmp(NM_CPIO, argv0) == 0) + (void)fprintf(listf, "%llu blocks\n", + (unsigned long long)((rdcnt ? rdcnt : wrcnt) / 5120)); + else if (strcmp(NM_TAR, argv0) != 0) + (void)fprintf(listf, +# ifdef NET2_STAT + "%s: %s vol %d, %lu files, %lu bytes read, %lu bytes written.\n", + argv0, frmt->name, arvol-1, flcnt, rdcnt, wrcnt); +# else + "%s: %s vol %d, %ju files, %ju bytes read, %ju bytes written.\n", + argv0, frmt->name, arvol-1, (uintmax_t)flcnt, + (uintmax_t)rdcnt, (uintmax_t)wrcnt); +# endif + (void)fflush(listf); + flcnt = 0; +} + +/* + * ar_drain() + * drain any archive format independent padding from an archive read + * from a socket or a pipe. This is to prevent the process on the + * other side of the pipe from getting a SIGPIPE (pax will stop + * reading an archive once a format dependent trailer is detected). + */ +void +ar_drain(void) +{ + int res; + char drbuf[MAXBLK]; + + /* + * we only drain from a pipe/socket. Other devices can be closed + * without reading up to end of file. We sure hope that pipe is closed + * on the other side so we will get an EOF. + */ + if ((artyp != ISPIPE) || (lstrval <= 0)) + return; + + /* + * keep reading until pipe is drained + */ + while ((res = read(arfd, drbuf, sizeof(drbuf))) > 0) + ; + lstrval = res; +} + +/* + * ar_set_wr() + * Set up device right before switching from read to write in an append. + * device dependent code (if required) to do this should be added here. + * For all archive devices we are already positioned at the place we want + * to start writing when this routine is called. + * Return: + * 0 if all ready to write, -1 otherwise + */ + +int +ar_set_wr(void) +{ + off_t cpos; + + /* + * we must make sure the trailer is rewritten on append, ar_next() + * will stop us if the archive containing the trailer was not written + */ + wr_trail = 0; + + /* + * Add any device dependent code as required here + */ + if (artyp != ISREG) + return(0); + /* + * Ok we have an archive in a regular file. If we were rewriting a + * file, we must get rid of all the stuff after the current offset + * (it was not written by pax). + */ + if (((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) || + (ftruncate(arfd, cpos) < 0)) { + syswarn(1, errno, "Unable to truncate archive file"); + return(-1); + } + return(0); +} + +/* + * ar_app_ok() + * check if the last volume in the archive allows appends. We cannot check + * this until we are ready to write since there is no spec that says all + * volumes in a single archive have to be of the same type... + * Return: + * 0 if we can append, -1 otherwise. + */ + +int +ar_app_ok(void) +{ + if (artyp == ISPIPE) { + paxwarn(1, "Cannot append to an archive obtained from a pipe."); + return(-1); + } + + if (!invld_rec) + return(0); + paxwarn(1,"Cannot append, device record size %d does not support %s spec", + rdblksz, argv0); + return(-1); +} + +/* + * ar_read() + * read up to a specified number of bytes from the archive into the + * supplied buffer. When dealing with tapes we may not always be able to + * read what we want. + * Return: + * Number of bytes in buffer. 0 for end of file, -1 for a read error. + */ + +int +ar_read(char *buf, int cnt) +{ + int res = 0; + + /* + * if last i/o was in error, no more reads until reset or new volume + */ + if (lstrval <= 0) + return(lstrval); + + /* + * how we read must be based on device type + */ + switch (artyp) { + case ISTAPE: + if ((res = read(arfd, buf, cnt)) > 0) { + /* + * CAUTION: tape systems may not always return the same + * sized records so we leave blksz == MAXBLK. The + * physical record size that a tape drive supports is + * very hard to determine in a uniform and portable + * manner. + */ + io_ok = 1; + if (res != rdblksz) { + /* + * Record size changed. If this is happens on + * any record after the first, we probably have + * a tape drive which has a fixed record size + * we are getting multiple records in a single + * read). Watch out for record blocking that + * violates pax spec (must be a multiple of + * BLKMULT). + */ + rdblksz = res; + if (rdblksz % BLKMULT) + invld_rec = 1; + } + return(res); + } + break; + case ISREG: + case ISBLK: + case ISCHR: + case ISPIPE: + default: + /* + * Files are so easy to deal with. These other things cannot + * be trusted at all. So when we are dealing with character + * devices and pipes we just take what they have ready for us + * and return. Trying to do anything else with them runs the + * risk of failure. + */ + if ((res = read(arfd, buf, cnt)) > 0) { + io_ok = 1; + return(res); + } + break; + } + + /* + * We are in trouble at this point, something is broken... + */ + lstrval = res; + if (res < 0) + syswarn(1, errno, "Failed read on archive volume %d", arvol); + else + paxwarn(0, "End of archive volume %d reached", arvol); + return(res); +} + +/* + * ar_write() + * Write a specified number of bytes in supplied buffer to the archive + * device so it appears as a single "block". Deals with errors and tries + * to recover when faced with short writes. + * Return: + * Number of bytes written. 0 indicates end of volume reached and with no + * flaws (as best that can be detected). A -1 indicates an unrecoverable + * error in the archive occured. + */ + +int +ar_write(char *buf, int bsz) +{ + int res; + off_t cpos; + + /* + * do not allow pax to create a "bad" archive. Once a write fails on + * an archive volume prevent further writes to it. + */ + if (lstrval <= 0) + return(lstrval); + + if ((res = write(arfd, buf, bsz)) == bsz) { + wr_trail = 1; + io_ok = 1; + return(bsz); + } + /* + * write broke, see what we can do with it. We try to send any partial + * writes that may violate pax spec to the next archive volume. + */ + if (res < 0) + lstrval = res; + else + lstrval = 0; + + switch (artyp) { + case ISREG: + if ((res > 0) && (res % BLKMULT)) { + /* + * try to fix up partial writes which are not BLKMULT + * in size by forcing the runt record to next archive + * volume + */ + if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) + break; + cpos -= (off_t)res; + if (ftruncate(arfd, cpos) < 0) + break; + res = lstrval = 0; + break; + } + if (res >= 0) + break; + /* + * if file is out of space, handle it like a return of 0 + */ + if ((errno == ENOSPC) || (errno == EFBIG) || (errno == EDQUOT)) + res = lstrval = 0; + break; + case ISTAPE: + case ISCHR: + case ISBLK: + if (res >= 0) + break; + if (errno == EACCES) { + paxwarn(0, "Write failed, archive is write protected."); + res = lstrval = 0; + return(0); + } + /* + * see if we reached the end of media, if so force a change to + * the next volume + */ + if ((errno == ENOSPC) || (errno == EIO) || (errno == ENXIO)) + res = lstrval = 0; + break; + case ISPIPE: + default: + /* + * we cannot fix errors to these devices + */ + break; + } + + /* + * Better tell the user the bad news... + * if this is a block aligned archive format, we may have a bad archive + * if the format wants the header to start at a BLKMULT boundary. While + * we can deal with the mis-aligned data, it violates spec and other + * archive readers will likely fail. if the format is not block + * aligned, the user may be lucky (and the archive is ok). + */ + if (res >= 0) { + if (res > 0) + wr_trail = 1; + io_ok = 1; + } + + /* + * If we were trying to rewrite the trailer and it didn't work, we + * must quit right away. + */ + if (!wr_trail && (res <= 0)) { + paxwarn(1,"Unable to append, trailer re-write failed. Quitting."); + return(res); + } + + if (res == 0) + paxwarn(0, "End of archive volume %d reached", arvol); + else if (res < 0) + syswarn(1, errno, "Failed write to archive volume: %d", arvol); + else if (!frmt->blkalgn || ((res % frmt->blkalgn) == 0)) + paxwarn(0,"WARNING: partial archive write. Archive MAY BE FLAWED"); + else + paxwarn(1,"WARNING: partial archive write. Archive IS FLAWED"); + return(res); +} + +/* + * ar_rdsync() + * Try to move past a bad spot on a flawed archive as needed to continue + * I/O. Clears error flags to allow I/O to continue. + * Return: + * 0 when ok to try i/o again, -1 otherwise. + */ + +int +ar_rdsync(void) +{ + long fsbz; + off_t cpos; + off_t mpos; + struct mtop mb; + + /* + * Fail resync attempts at user request (done) or this is going to be + * an update/append to an existing archive. If last i/o hit media end, + * we need to go to the next volume not try a resync. + */ + if ((done > 0) || (lstrval == 0)) + return(-1); + + if ((act == APPND) || (act == ARCHIVE)) { + paxwarn(1, "Cannot allow updates to an archive with flaws."); + return(-1); + } + if (io_ok) + did_io = 1; + + switch(artyp) { + case ISTAPE: + /* + * if the last i/o was a successful data transfer, we assume + * the fault is just a bad record on the tape that we are now + * past. If we did not get any data since the last resync try + * to move the tape forward one PHYSICAL record past any + * damaged tape section. Some tape drives are stubborn and need + * to be pushed. + */ + if (io_ok) { + io_ok = 0; + lstrval = 1; + break; + } + mb.mt_op = MTFSR; + mb.mt_count = 1; + if (ioctl(arfd, MTIOCTOP, &mb) < 0) + break; + lstrval = 1; + break; + case ISREG: + case ISCHR: + case ISBLK: + /* + * try to step over the bad part of the device. + */ + io_ok = 0; + if (((fsbz = arsb.st_blksize) <= 0) || (artyp != ISREG)) + fsbz = BLKMULT; + if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) + break; + mpos = fsbz - (cpos % (off_t)fsbz); + if (lseek(arfd, mpos, SEEK_CUR) < 0) + break; + lstrval = 1; + break; + case ISPIPE: + default: + /* + * cannot recover on these archive device types + */ + io_ok = 0; + break; + } + if (lstrval <= 0) { + paxwarn(1, "Unable to recover from an archive read failure."); + return(-1); + } + paxwarn(0, "Attempting to recover from an archive read failure."); + return(0); +} + +/* + * ar_fow() + * Move the I/O position within the archive foward the specified number of + * bytes as supported by the device. If we cannot move the requested + * number of bytes, return the actual number of bytes moved in skipped. + * Return: + * 0 if moved the requested distance, -1 on complete failure, 1 on + * partial move (the amount moved is in skipped) + */ + +int +ar_fow(off_t sksz, off_t *skipped) +{ + off_t cpos; + off_t mpos; + + *skipped = 0; + if (sksz <= 0) + return(0); + + /* + * we cannot move foward at EOF or error + */ + if (lstrval <= 0) + return(lstrval); + + /* + * Safer to read forward on devices where it is hard to find the end of + * the media without reading to it. With tapes we cannot be sure of the + * number of physical blocks to skip (we do not know physical block + * size at this point), so we must only read foward on tapes! + */ + if (artyp != ISREG) + return(0); + + /* + * figure out where we are in the archive + */ + if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) >= 0) { + /* + * we can be asked to move farther than there are bytes in this + * volume, if so, just go to file end and let normal buf_fill() + * deal with the end of file (it will go to next volume by + * itself) + */ + if ((mpos = cpos + sksz) > arsb.st_size) { + *skipped = arsb.st_size - cpos; + mpos = arsb.st_size; + } else + *skipped = sksz; + if (lseek(arfd, mpos, SEEK_SET) >= 0) + return(0); + } + syswarn(1, errno, "Forward positioning operation on archive failed"); + lstrval = -1; + return(-1); +} + +/* + * ar_rev() + * move the i/o position within the archive backwards the specified byte + * count as supported by the device. With tapes drives we RESET rdblksz to + * the PHYSICAL blocksize. + * NOTE: We should only be called to move backwards so we can rewrite the + * last records (the trailer) of an archive (APPEND). + * Return: + * 0 if moved the requested distance, -1 on complete failure + */ + +int +ar_rev(off_t sksz) +{ + off_t cpos; + struct mtop mb; + int phyblk; + + /* + * make sure we do not have try to reverse on a flawed archive + */ + if (lstrval < 0) + return(lstrval); + + switch(artyp) { + case ISPIPE: + if (sksz <= 0) + break; + /* + * cannot go backwards on these critters + */ + paxwarn(1, "Reverse positioning on pipes is not supported."); + lstrval = -1; + return(-1); + case ISREG: + case ISBLK: + case ISCHR: + default: + if (sksz <= 0) + break; + + /* + * For things other than files, backwards movement has a very + * high probability of failure as we really do not know the + * true attributes of the device we are talking to (the device + * may not even have the ability to lseek() in any direction). + * First we figure out where we are in the archive. + */ + if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) { + syswarn(1, errno, + "Unable to obtain current archive byte offset"); + lstrval = -1; + return(-1); + } + + /* + * we may try to go backwards past the start when the archive + * is only a single record. If this hapens and we are on a + * multi volume archive, we need to go to the end of the + * previous volume and continue our movement backwards from + * there. + */ + if ((cpos -= sksz) < (off_t)0L) { + if (arvol > 1) { + /* + * this should never happen + */ + paxwarn(1,"Reverse position on previous volume."); + lstrval = -1; + return(-1); + } + cpos = (off_t)0L; + } + if (lseek(arfd, cpos, SEEK_SET) < 0) { + syswarn(1, errno, "Unable to seek archive backwards"); + lstrval = -1; + return(-1); + } + break; + case ISTAPE: + /* + * Calculate and move the proper number of PHYSICAL tape + * blocks. If the sksz is not an even multiple of the physical + * tape size, we cannot do the move (this should never happen). + * (We also cannot handler trailers spread over two vols). + * get_phys() also makes sure we are in front of the filemark. + */ + if ((phyblk = get_phys()) <= 0) { + lstrval = -1; + return(-1); + } + + /* + * make sure future tape reads only go by physical tape block + * size (set rdblksz to the real size). + */ + rdblksz = phyblk; + + /* + * if no movement is required, just return (we must be after + * get_phys() so the physical blocksize is properly set) + */ + if (sksz <= 0) + break; + + /* + * ok we have to move. Make sure the tape drive can do it. + */ + if (sksz % phyblk) { + paxwarn(1, + "Tape drive unable to backspace requested amount"); + lstrval = -1; + return(-1); + } + + /* + * move backwards the requested number of bytes + */ + mb.mt_op = MTBSR; + mb.mt_count = sksz/phyblk; + if (ioctl(arfd, MTIOCTOP, &mb) < 0) { + syswarn(1,errno, "Unable to backspace tape %d blocks.", + mb.mt_count); + lstrval = -1; + return(-1); + } + break; + } + lstrval = 1; + return(0); +} + +/* + * get_phys() + * Determine the physical block size on a tape drive. We need the physical + * block size so we know how many bytes we skip over when we move with + * mtio commands. We also make sure we are BEFORE THE TAPE FILEMARK when + * return. + * This is one really SLOW routine... + * Return: + * physical block size if ok (ok > 0), -1 otherwise + */ + +static int +get_phys(void) +{ + int padsz = 0; + int res; + int phyblk; + struct mtop mb; + char scbuf[MAXBLK]; + + /* + * move to the file mark, and then back up one record and read it. + * this should tell us the physical record size the tape is using. + */ + if (lstrval == 1) { + /* + * we know we are at file mark when we get back a 0 from + * read() + */ + while ((res = read(arfd, scbuf, sizeof(scbuf))) > 0) + padsz += res; + if (res < 0) { + syswarn(1, errno, "Unable to locate tape filemark."); + return(-1); + } + } + + /* + * move backwards over the file mark so we are at the end of the + * last record. + */ + mb.mt_op = MTBSF; + mb.mt_count = 1; + if (ioctl(arfd, MTIOCTOP, &mb) < 0) { + syswarn(1, errno, "Unable to backspace over tape filemark."); + return(-1); + } + + /* + * move backwards so we are in front of the last record and read it to + * get physical tape blocksize. + */ + mb.mt_op = MTBSR; + mb.mt_count = 1; + if (ioctl(arfd, MTIOCTOP, &mb) < 0) { + syswarn(1, errno, "Unable to backspace over last tape block."); + return(-1); + } + if ((phyblk = read(arfd, scbuf, sizeof(scbuf))) <= 0) { + syswarn(1, errno, "Cannot determine archive tape blocksize."); + return(-1); + } + + /* + * read foward to the file mark, then back up in front of the filemark + * (this is a bit paranoid, but should be safe to do). + */ + while ((res = read(arfd, scbuf, sizeof(scbuf))) > 0) + ; + if (res < 0) { + syswarn(1, errno, "Unable to locate tape filemark."); + return(-1); + } + mb.mt_op = MTBSF; + mb.mt_count = 1; + if (ioctl(arfd, MTIOCTOP, &mb) < 0) { + syswarn(1, errno, "Unable to backspace over tape filemark."); + return(-1); + } + + /* + * set lstrval so we know that the filemark has not been seen + */ + lstrval = 1; + + /* + * return if there was no padding + */ + if (padsz == 0) + return(phyblk); + + /* + * make sure we can move backwards over the padding. (this should + * never fail). + */ + if (padsz % phyblk) { + paxwarn(1, "Tape drive unable to backspace requested amount"); + return(-1); + } + + /* + * move backwards over the padding so the head is where it was when + * we were first called (if required). + */ + mb.mt_op = MTBSR; + mb.mt_count = padsz/phyblk; + if (ioctl(arfd, MTIOCTOP, &mb) < 0) { + syswarn(1,errno,"Unable to backspace tape over %d pad blocks", + mb.mt_count); + return(-1); + } + return(phyblk); +} + +/* + * ar_next() + * prompts the user for the next volume in this archive. For some devices + * we may allow the media to be changed. Otherwise a new archive is + * prompted for. By pax spec, if there is no controlling tty or an eof is + * read on tty input, we must quit pax. + * Return: + * 0 when ready to continue, -1 when all done + */ + +int +ar_next(void) +{ + static char *arcbuf; + char buf[PAXPATHLEN+2]; + sigset_t o_mask; + + /* + * WE MUST CLOSE THE DEVICE. A lot of devices must see last close, (so + * things like writing EOF etc will be done) (Watch out ar_close() can + * also be called via a signal handler, so we must prevent a race. + */ + if (sigprocmask(SIG_BLOCK, &s_mask, &o_mask) < 0) + syswarn(0, errno, "Unable to set signal mask"); + ar_close(); + if (sigprocmask(SIG_SETMASK, &o_mask, NULL) < 0) + syswarn(0, errno, "Unable to restore signal mask"); + + if (done || !wr_trail || strcmp(NM_TAR, argv0) == 0) + return(-1); + + tty_prnt("\nATTENTION! %s archive volume change required.\n", argv0); + + /* + * if i/o is on stdin or stdout, we cannot reopen it (we do not know + * the name), the user will be forced to type it in. + */ + if (strcmp(arcname, stdo) && strcmp(arcname, stdn) && (artyp != ISREG) + && (artyp != ISPIPE)) { + if (artyp == ISTAPE) { + tty_prnt("%s ready for archive tape volume: %d\n", + arcname, arvol); + tty_prnt("Load the NEXT TAPE on the tape drive"); + } else { + tty_prnt("%s ready for archive volume: %d\n", + arcname, arvol); + tty_prnt("Load the NEXT STORAGE MEDIA (if required)"); + } + + if ((act == ARCHIVE) || (act == APPND)) + tty_prnt(" and make sure it is WRITE ENABLED.\n"); + else + tty_prnt("\n"); + + for(;;) { + tty_prnt("Type \"y\" to continue, \".\" to quit %s,", + argv0); + tty_prnt(" or \"s\" to switch to new device.\nIf you"); + tty_prnt(" cannot change storage media, type \"s\"\n"); + tty_prnt("Is the device ready and online? > "); + + if ((tty_read(buf,sizeof(buf))<0) || !strcmp(buf,".")){ + done = 1; + lstrval = -1; + tty_prnt("Quitting %s!\n", argv0); + vfpart = 0; + return(-1); + } + + if ((buf[0] == '\0') || (buf[1] != '\0')) { + tty_prnt("%s unknown command, try again\n",buf); + continue; + } + + switch (buf[0]) { + case 'y': + case 'Y': + /* + * we are to continue with the same device + */ + if (ar_open(arcname) >= 0) + return(0); + tty_prnt("Cannot re-open %s, try again\n", + arcname); + continue; + case 's': + case 'S': + /* + * user wants to open a different device + */ + tty_prnt("Switching to a different archive\n"); + break; + default: + tty_prnt("%s unknown command, try again\n",buf); + continue; + } + break; + } + } else + tty_prnt("Ready for archive volume: %d\n", arvol); + + /* + * have to go to a different archive + */ + for (;;) { + tty_prnt("Input archive name or \".\" to quit %s.\n", argv0); + tty_prnt("Archive name > "); + + if ((tty_read(buf, sizeof(buf)) < 0) || !strcmp(buf, ".")) { + done = 1; + lstrval = -1; + tty_prnt("Quitting %s!\n", argv0); + vfpart = 0; + return(-1); + } + if (buf[0] == '\0') { + tty_prnt("Empty file name, try again\n"); + continue; + } + if (!strcmp(buf, "..")) { + tty_prnt("Illegal file name: .. try again\n"); + continue; + } + if (strlen(buf) > PAXPATHLEN) { + tty_prnt("File name too long, try again\n"); + continue; + } + + /* + * try to open new archive + */ + if (ar_open(buf) >= 0) { + free(arcbuf); + if ((arcbuf = strdup(buf)) == NULL) { + done = 1; + lstrval = -1; + paxwarn(0, "Cannot save archive name."); + return(-1); + } + arcname = arcbuf; + break; + } + tty_prnt("Cannot open %s, try again\n", buf); + continue; + } + return(0); +} + +/* + * ar_start_gzip() + * starts the gzip compression/decompression process as a child, using magic + * to keep the fd the same in the calling function (parent). + */ +void +ar_start_gzip(int fd, const char *gzip_prog, int wr) +{ + int fds[2]; + const char *gzip_flags; + + if (pipe(fds) < 0) + err(1, "could not pipe"); + zpid = fork(); + if (zpid < 0) + err(1, "could not fork"); + + /* parent */ + if (zpid) { + if (wr) + dup2(fds[1], fd); + else + dup2(fds[0], fd); + close(fds[0]); + close(fds[1]); + } else { + if (wr) { + dup2(fds[0], STDIN_FILENO); + dup2(fd, STDOUT_FILENO); + gzip_flags = "-c"; + } else { + dup2(fds[1], STDOUT_FILENO); + dup2(fd, STDIN_FILENO); + gzip_flags = "-dc"; + } + close(fds[0]); + close(fds[1]); + if (execlp(gzip_prog, gzip_prog, gzip_flags, + (char *)NULL) < 0) + err(1, "could not exec"); + /* NOTREACHED */ + } +} |