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- /* $Source: /u/mark/src/pax/RCS/buffer.c,v $
- *
- * $Revision: 1.2 $
- *
- * buffer.c - Buffer management functions
- *
- * DESCRIPTION
- *
- * These functions handle buffer manipulations for the archiving
- * formats. Functions are provided to get memory for buffers,
- * flush buffers, read and write buffers and de-allocate buffers.
- * Several housekeeping functions are provided as well to get some
- * information about how full buffers are, etc.
- *
- * AUTHOR
- *
- * Mark H. Colburn, NAPS International (mark@jhereg.mn.org)
- *
- * Sponsored by The USENIX Association for public distribution.
- *
- * Copyright (c) 1989 Mark H. Colburn.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms are permitted
- * provided that the above copyright notice is duplicated in all such
- * forms and that any documentation, advertising materials, and other
- * materials related to such distribution and use acknowledge that the
- * software was developed * by Mark H. Colburn and sponsored by The
- * USENIX Association.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
- * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
- *
- * $Log: buffer.c,v $
- * Revision 1.2 89/02/12 10:04:02 mark
- * 1.2 release fixes
- *
- * Revision 1.1 88/12/23 18:02:01 mark
- * Initial revision
- *
- */
- #ifndef lint
- static char *ident = "$Id: buffer.c,v 1.2 89/02/12 10:04:02 mark Exp $";
- static char *copyright = "Copyright (c) 1989 Mark H. Colburn.\nAll rights reserved.\n";
- #endif /* ! lint */
- /* Headers */
- #include "pax.h"
- /* Function Prototypes */
- #ifdef __STDC__
- static int ar_write(int, char *, uint);
- static void buf_pad(OFFSET);
- static int indata(int, OFFSET, char *);
- static void outflush(void);
- static void buf_use(uint);
- static int buf_in_avail(char **, uint *);
- static uint buf_out_avail(char **);
- #else /* !__STDC__ */
- static int ar_write();
- static void buf_pad();
- static int indata();
- static void outflush();
- static void buf_use();
- static int buf_in_avail();
- static uint buf_out_avail();
- #endif /* __STDC__ */
- /* inentry - install a single archive entry
- *
- * DESCRIPTION
- *
- * Inentry reads an archive entry from the archive file and writes it
- * out the the named file. If we are in PASS mode during archive
- * processing, the pass() function is called, otherwise we will
- * extract from the archive file.
- *
- * Inentry actaully calls indata to process the actual data to the
- * file.
- *
- * PARAMETERS
- *
- * char *name - name of the file to extract from the archive
- * Stat *asb - stat block of the file to be extracted from the
- * archive.
- *
- * RETURNS
- *
- * Returns zero if successful, -1 otherwise.
- */
- #ifdef __STDC__
- int inentry(char *name, Stat *asb)
- #else
- int inentry(name, asb)
- char *name;
- Stat *asb;
- #endif
- {
- Link *linkp;
- int ifd;
- int ofd;
- time_t tstamp[2];
- if ((ofd = openout(name, asb, linkp = linkfrom(name, asb), 0)) > 0) {
- if (asb->sb_size || linkp == (Link *)NULL || linkp->l_size == 0) {
- close(indata(ofd, asb->sb_size, name));
- } else if ((ifd = open(linkp->l_path->p_name, O_RDONLY)) < 0) {
- warn(linkp->l_path->p_name, strerror());
- } else {
- passdata(linkp->l_path->p_name, ifd, name, ofd);
- close(ifd);
- close(ofd);
- }
- } else {
- return(buf_skip((OFFSET) asb->sb_size) >= 0);
- }
- tstamp[0] = (!f_pass && f_access_time) ? asb->sb_atime : time((time_t *) 0);
- tstamp[1] = f_mtime ? asb->sb_mtime : time((time_t *) 0);
- utime(name, tstamp);
- return (0);
- }
- /* outdata - write archive data
- *
- * DESCRIPTION
- *
- * Outdata transfers data from the named file to the archive buffer.
- * It knows about the file padding which is required by tar, but no
- * by cpio. Outdata continues after file read errors, padding with
- * null characters if neccessary. Closes the input file descriptor
- * when finished.
- *
- * PARAMETERS
- *
- * int fd - file descriptor of file to read data from
- * char *name - name of file
- * OFFSET size - size of the file
- *
- */
- #ifdef __STDC__
- void outdata(int fd, char *name, OFFSET size)
- #else
- void outdata(fd, name, size)
- int fd;
- char *name;
- OFFSET size;
- #endif
- {
- uint chunk;
- int got;
- int oops;
- uint avail;
- int pad;
- char *buf;
- oops = got = 0;
- if (pad = (size % BLOCKSIZE)) {
- pad = (BLOCKSIZE - pad);
- }
- while (size) {
- avail = buf_out_avail(&buf);
- size -= (chunk = size < avail ? (uint) size : avail);
- if (oops == 0 && (got = read(fd, buf, (unsigned int) chunk)) < 0) {
- oops = -1;
- warn(name, strerror());
- got = 0;
- }
- if (got < chunk) {
- if (oops == 0) {
- oops = -1;
- }
- warn(name, "Early EOF");
- while (got < chunk) {
- buf[got++] = '\0';
- }
- }
- buf_use(chunk);
- }
- close(fd);
- if (ar_format == TAR) {
- buf_pad((OFFSET) pad);
- }
- }
- /* write_eot - write the end of archive record(s)
- *
- * DESCRIPTION
- *
- * Write out an End-Of-Tape record. We actually zero at least one
- * record, through the end of the block. Old tar writes garbage after
- * two zeroed records -- and PDtar used to.
- */
- #ifdef __STDC__
- void write_eot(void)
- #else
- void write_eot()
- #endif
- {
- OFFSET pad;
- char header[M_STRLEN + H_STRLEN + 1];
- if (ar_format == TAR) {
- /* write out two zero blocks for trailer */
- pad = 2 * BLOCKSIZE;
- } else {
- if (pad = (total + M_STRLEN + H_STRLEN + TRAILZ) % BLOCKSIZE) {
- pad = BLOCKSIZE - pad;
- }
- strcpy(header, M_ASCII);
- sprintf(header + M_STRLEN, H_PRINT, 0, 0,
- 0, 0, 0, 1, 0, (time_t) 0, TRAILZ, pad);
- outwrite(header, M_STRLEN + H_STRLEN);
- outwrite(TRAILER, TRAILZ);
- }
- buf_pad((OFFSET) pad);
- outflush();
- }
-
- /* outwrite - write archive data
- *
- * DESCRIPTION
- *
- * Writes out data in the archive buffer to the archive file. The
- * buffer index and the total byte count are incremented by the number
- * of data bytes written.
- *
- * PARAMETERS
- *
- * char *idx - pointer to data to write
- * uint len - length of the data to write
- */
- #ifdef __STDC__
- void outwrite(char *idx, uint len)
- #else
- void outwrite(idx, len)
- char *idx; /* pointer to data to write */
- uint len; /* length of data to write */
- #endif
- {
- uint have;
- uint want;
- char *endx;
- endx = idx + len;
- while (want = endx - idx) {
- if (bufend - bufidx < 0) {
- fatal("Buffer overlow in out_write\n");
- }
- if ((have = bufend - bufidx) == 0) {
- outflush();
- }
- if (have > want) {
- have = want;
- }
- memcpy(bufidx, idx, (int) have);
- bufidx += have;
- idx += have;
- total += have;
- }
- }
- /* passdata - copy data to one file
- *
- * DESCRIPTION
- *
- * Copies a file from one place to another. Doesn't believe in input
- * file descriptor zero (see description of kludge in openin() comments).
- * Closes the provided output file descriptor.
- *
- * PARAMETERS
- *
- * char *from - input file name (old file)
- * int ifd - input file descriptor
- * char *to - output file name (new file)
- * int ofd - output file descriptor
- */
- #ifdef __STDC__
- void passdata(char *from, int ifd, char *to, int ofd)
- #else
- void passdata(from, ifd, to, ofd)
- char *from;
- int ifd;
- char *to;
- int ofd;
- #endif
- {
- int got;
- int sparse;
- char block[BUFSIZ];
- if (ifd) {
- lseek(ifd, (OFFSET) 0, 0);
- sparse = 0;
- while ((got = read(ifd, block, sizeof(block))) > 0
- && (sparse = ar_write(ofd, block, (uint) got)) >= 0) {
- total += got;
- }
- if (got) {
- warn(got < 0 ? from : to, strerror());
- } else if (sparse > 0
- && (lseek(ofd, (OFFSET)(-sparse), 1) < 0
- || write(ofd, block, (uint) sparse) != sparse)) {
- warn(to, strerror());
- }
- }
- close(ofd);
- }
- /* buf_allocate - get space for the I/O buffer
- *
- * DESCRIPTION
- *
- * buf_allocate allocates an I/O buffer using malloc. The resulting
- * buffer is used for all data buffering throughout the program.
- * Buf_allocate must be called prior to any use of the buffer or any
- * of the buffering calls.
- *
- * PARAMETERS
- *
- * int size - size of the I/O buffer to request
- *
- * ERRORS
- *
- * If an invalid size is given for a buffer or if a buffer of the
- * required size cannot be allocated, then the function prints out an
- * error message and returns a non-zero exit status to the calling
- * process, terminating the program.
- *
- */
- #ifdef __STDC__
- void buf_allocate(OFFSET size)
- #else
- void buf_allocate(size)
- OFFSET size;
- #endif
- {
- if (size <= 0) {
- fatal("invalid value for blocksize");
- }
- if ((bufstart = malloc((unsigned) size)) == (char *)NULL) {
- fatal("Cannot allocate I/O buffer");
- }
- bufend = bufidx = bufstart;
- bufend += size;
- }
- /* buf_skip - skip input archive data
- *
- * DESCRIPTION
- *
- * Buf_skip skips past archive data. It is used when the length of
- * the archive data is known, and we do not wish to process the data.
- *
- * PARAMETERS
- *
- * OFFSET len - number of bytes to skip
- *
- * RETURNS
- *
- * Returns zero under normal circumstances, -1 if unreadable data is
- * encountered.
- */
- #ifdef __STDC__
- int buf_skip(OFFSET len)
- #else
- int buf_skip(len)
- OFFSET len;
- #endif
- {
- uint chunk;
- int corrupt = 0;
- while (len) {
- if (bufend - bufidx < 0) {
- fatal("Buffer overlow in buf_skip\n");
- }
- while ((chunk = bufend - bufidx) == 0) {
- corrupt |= ar_read();
- }
- if (chunk > len) {
- chunk = len;
- }
- bufidx += chunk;
- len -= chunk;
- total += chunk;
- }
- return (corrupt);
- }
- /* buf_read - read a given number of characters from the input archive
- *
- * DESCRIPTION
- *
- * Reads len number of characters from the input archive and
- * stores them in the buffer pointed at by dst.
- *
- * PARAMETERS
- *
- * char *dst - pointer to buffer to store data into
- * uint len - length of data to read
- *
- * RETURNS
- *
- * Returns zero with valid data, -1 if unreadable portions were
- * replaced by null characters.
- */
- #ifdef __STDC__
- int buf_read(char *dst, uint len)
- #else
- int buf_read(dst, len)
- char *dst;
- uint len;
- #endif
- {
- int have;
- int want;
- int corrupt = 0;
- char *endx = dst + len;
- while (want = endx - dst) {
- if (bufend - bufidx < 0) {
- fatal("Buffer overlow in buf_read\n");
- }
- while ((have = bufend - bufidx) == 0) {
- have = 0;
- corrupt |= ar_read();
- }
- if (have > want) {
- have = want;
- }
- memcpy(dst, bufidx, have);
- bufidx += have;
- dst += have;
- total += have;
- }
- return (corrupt);
- }
- /* indata - install data from an archive
- *
- * DESCRIPTION
- *
- * Indata writes size bytes of data from the archive buffer to the output
- * file specified by fd. The filename which is being written, pointed
- * to by name is provided only for diagnostics.
- *
- * PARAMETERS
- *
- * int fd - output file descriptor
- * OFFSET size - number of bytes to write to output file
- * char *name - name of file which corresponds to fd
- *
- * RETURNS
- *
- * Returns given file descriptor.
- */
- #ifdef __STDC__
- static int indata(int fd, OFFSET size, char *name)
- #else
- static int indata(fd, size, name)
- int fd;
- OFFSET size;
- char *name;
- #endif
- {
- uint chunk;
- char *oops;
- int sparse;
- int corrupt;
- char *buf;
- uint avail;
- corrupt = sparse = 0;
- oops = (char *)NULL;
- while (size) {
- corrupt |= buf_in_avail(&buf, &avail);
- size -= (chunk = size < avail ? (uint) size : avail);
- if (oops == (char *)NULL && (sparse = ar_write(fd, buf, chunk)) < 0) {
- oops = strerror();
- }
- buf_use(chunk);
- }
- if (corrupt) {
- warn(name, "Corrupt archive data");
- }
- if (oops) {
- warn(name, oops);
- } else if (sparse > 0 && (lseek(fd, (OFFSET) - 1, 1) < 0
- || write(fd, "", 1) != 1)) {
- warn(name, strerror());
- }
- return (fd);
- }
- /* outflush - flush the output buffer
- *
- * DESCRIPTION
- *
- * The output buffer is written, if there is anything in it, to the
- * archive file.
- */
- #ifdef __STDC__
- static void outflush(void)
- #else
- static void outflush()
- #endif
- {
- char *buf;
- int got;
- uint len;
- /* if (bufidx - buf > 0) */
- for (buf = bufstart; len = bufidx - buf;) {
- if ((got = write(archivefd, buf, MIN(len, blocksize))) > 0) {
- buf += got;
- } else if (got < 0) {
- next(AR_WRITE);
- }
- }
- bufend = (bufidx = bufstart) + blocksize;
- }
- /* ar_read - fill the archive buffer
- *
- * DESCRIPTION
- *
- * Remembers mid-buffer read failures and reports them the next time
- * through. Replaces unreadable data with null characters. Resets
- * the buffer pointers as appropriate.
- *
- * RETURNS
- *
- * Returns zero with valid data, -1 otherwise.
- */
- #ifdef __STDC__
- int ar_read(void)
- #else
- int ar_read()
- #endif
- {
- int got;
- static int failed;
- bufend = bufidx = bufstart;
- if (!failed) {
- if (areof) {
- if (total == 0) {
- fatal("No input");
- } else {
- next(AR_READ);
- }
- }
- while (!failed && !areof && bufstart + blocksize - bufend >= blocksize) {
- if ((got = read(archivefd, bufend, (unsigned int) blocksize)) > 0) {
- bufend += got;
- } else if (got < 0) {
- failed = -1;
- warnarch(strerror(), (OFFSET) 0 - (bufend - bufidx));
- } else {
- ++areof;
- }
- }
- }
- if (failed && bufend == bufstart) {
- failed = 0;
- for (got = 0; got < blocksize; ++got) {
- *bufend++ = '\0';
- }
- return (-1);
- }
- return (0);
- }
- /* ar_write - write a filesystem block
- *
- * DESCRIPTION
- *
- * Writes len bytes of data data from the specified buffer to the
- * specified file. Seeks past sparse blocks.
- *
- * PARAMETERS
- *
- * int fd - file to write to
- * char *buf - buffer to get data from
- * uint len - number of bytes to transfer
- *
- * RETURNS
- *
- * Returns 0 if the block was written, the given length for a sparse
- * block or -1 if unsuccessful.
- */
- #ifdef __STDC__
- static int ar_write(int fd, char *buf, uint len)
- #else
- static int ar_write(fd, buf, len)
- int fd;
- char *buf;
- uint len;
- #endif
- {
- char *bidx;
- char *bend;
- bend = (bidx = buf) + len;
- while (bidx < bend) {
- if (*bidx++) {
- return (write(fd, buf, len) == len ? 0 : -1);
- }
- }
- return (lseek(fd, (OFFSET) len, 1) < 0 ? -1 : len);
- }
- /* buf_pad - pad the archive buffer
- *
- * DESCRIPTION
- *
- * Buf_pad writes len zero bytes to the archive buffer in order to
- * pad it.
- *
- * PARAMETERS
- *
- * OFFSET pad - number of zero bytes to pad
- *
- */
- #ifdef __STDC__
- static void buf_pad(OFFSET pad)
- #else
- static void buf_pad(pad)
- OFFSET pad;
- #endif
- {
- int idx;
- int have;
- while (pad) {
- if ((have = bufend - bufidx) > pad) {
- have = pad;
- }
- for (idx = 0; idx < have; ++idx) {
- *bufidx++ = '\0';
- }
- total += have;
- pad -= have;
- if (bufend - bufidx == 0) {
- outflush();
- }
- }
- }
- /* buf_use - allocate buffer space
- *
- * DESCRIPTION
- *
- * Buf_use marks space in the buffer as being used; advancing both the
- * buffer index (bufidx) and the total byte count (total).
- *
- * PARAMETERS
- *
- * uint len - Amount of space to allocate in the buffer
- */
- #ifdef __STDC__
- static void buf_use(uint len)
- #else
- static void buf_use(len)
- uint len;
- #endif
- {
- bufidx += len;
- total += len;
- }
- /* buf_in_avail - index available input data within the buffer
- *
- * DESCRIPTION
- *
- * Buf_in_avail fills the archive buffer, and points the bufp
- * parameter at the start of the data. The lenp parameter is
- * modified to contain the number of bytes which were read.
- *
- * PARAMETERS
- *
- * char **bufp - pointer to the buffer to read data into
- * uint *lenp - pointer to the number of bytes which were read
- * (returned to the caller)
- *
- * RETURNS
- *
- * Stores a pointer to the data and its length in given locations.
- * Returns zero with valid data, -1 if unreadable portions were
- * replaced with nulls.
- *
- * ERRORS
- *
- * If an error occurs in ar_read, the error code is returned to the
- * calling function.
- *
- */
- #ifdef __STDC__
- static int buf_in_avail(char **bufp, uint *lenp)
- #else
- static int buf_in_avail(bufp, lenp)
- char **bufp;
- uint *lenp;
- #endif
- {
- uint have;
- int corrupt = 0;
- while ((have = bufend - bufidx) == 0) {
- corrupt |= ar_read();
- }
- *bufp = bufidx;
- *lenp = have;
- return (corrupt);
- }
- /* buf_out_avail - index buffer space for archive output
- *
- * DESCRIPTION
- *
- * Stores a buffer pointer at a given location. Returns the number
- * of bytes available.
- *
- * PARAMETERS
- *
- * char **bufp - pointer to the buffer which is to be stored
- *
- * RETURNS
- *
- * The number of bytes which are available in the buffer.
- *
- */
- #ifdef __STDC__
- static uint buf_out_avail(char **bufp)
- #else
- static uint buf_out_avail(bufp)
- char **bufp;
- #endif
- {
- int have;
- if (bufend - bufidx < 0) {
- fatal("Buffer overlow in buf_out_avail\n");
- }
- if ((have = bufend - bufidx) == 0) {
- outflush();
- }
- *bufp = bufidx;
- return (have);
- }
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