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/*
** Copyright 1998-2003 University of Illinois Board of Trustees
** Copyright 1998-2003 Mark D. Roth
** All rights reserved.
**
** block.c - libtar code to handle tar archive header blocks
**
** Mark D. Roth <roth@uiuc.edu>
** Campus Information Technologies and Educational Services
** University of Illinois at Urbana-Champaign
*/
#include <libtarint/internal.h>
#include <errno.h>
#ifdef STDC_HEADERS
# include <string.h>
# include <stdlib.h>
#endif
#define BIT_ISSET(bitmask, bit) ((bitmask) & (bit))
/* read a header block */
int
th_read_internal(TAR *t)
{
ssize_t i;
int num_zero_blocks = 0;
#ifdef DEBUG
printf("==> th_read_internal(TAR=\"%s\")\n", t->pathname);
#endif
while ((i = tar_block_read(t, &(t->th_buf))) == T_BLOCKSIZE)
{
/* two all-zero blocks mark EOF */
if (t->th_buf.name[0] == '\0')
{
num_zero_blocks++;
if (!BIT_ISSET(t->options, TAR_IGNORE_EOT)
&& num_zero_blocks >= 2)
return 0; /* EOF */
else
continue;
}
/* verify magic and version */
if (BIT_ISSET(t->options, TAR_CHECK_MAGIC)
&& strncmp(t->th_buf.magic, TMAGIC, TMAGLEN - 1) != 0)
{
#ifdef DEBUG
puts("!!! unknown magic value in tar header");
#endif
return -2;
}
if (BIT_ISSET(t->options, TAR_CHECK_VERSION)
&& strncmp(t->th_buf.version, TVERSION, TVERSLEN) != 0)
{
#ifdef DEBUG
puts("!!! unknown version value in tar header");
#endif
return -2;
}
/* check chksum */
if (!BIT_ISSET(t->options, TAR_IGNORE_CRC)
&& !th_crc_ok(t))
{
#ifdef DEBUG
puts("!!! tar header checksum error");
#endif
return -2;
}
break;
}
#ifdef DEBUG
printf("<== th_read_internal(): returning %d\n", i);
#endif
return (int)i;
}
/* wrapper function for th_read_internal() to handle GNU extensions */
int
th_read(TAR *t)
{
ssize_t i, j;
size_t sz;
char *ptr;
#ifdef DEBUG
printf("==> th_read(t=0x%lx)\n", t);
#endif
if (t->th_buf.gnu_longname != NULL)
free(t->th_buf.gnu_longname);
if (t->th_buf.gnu_longlink != NULL)
free(t->th_buf.gnu_longlink);
memset(&(t->th_buf), 0, sizeof(struct tar_header));
i = th_read_internal(t);
if (i == 0)
return 1;
else if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
/* check for GNU long link extention */
if (TH_ISLONGLINK(t))
{
sz = th_get_size(t);
j = (sz / T_BLOCKSIZE) + (sz % T_BLOCKSIZE ? 1 : 0);
#ifdef DEBUG
printf(" th_read(): GNU long linkname detected "
"(%ld bytes, %d blocks)\n", sz, j);
#endif
t->th_buf.gnu_longlink = (char *)malloc(j * T_BLOCKSIZE);
if (t->th_buf.gnu_longlink == NULL)
return -1;
for (ptr = t->th_buf.gnu_longlink; j > 0;
j--, ptr += T_BLOCKSIZE)
{
#ifdef DEBUG
printf(" th_read(): reading long linkname "
"(%d blocks left, ptr == %ld)\n", j, ptr);
#endif
i = tar_block_read(t, ptr);
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
#ifdef DEBUG
printf(" th_read(): read block == \"%s\"\n", ptr);
#endif
}
#ifdef DEBUG
printf(" th_read(): t->th_buf.gnu_longlink == \"%s\"\n",
t->th_buf.gnu_longlink);
#endif
i = th_read_internal(t);
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
}
/* check for GNU long name extention */
if (TH_ISLONGNAME(t))
{
sz = th_get_size(t);
j = (sz / T_BLOCKSIZE) + (sz % T_BLOCKSIZE ? 1 : 0);
#ifdef DEBUG
printf(" th_read(): GNU long filename detected "
"(%ld bytes, %d blocks)\n", sz, j);
#endif
t->th_buf.gnu_longname = (char *)malloc(j * T_BLOCKSIZE);
if (t->th_buf.gnu_longname == NULL)
return -1;
for (ptr = t->th_buf.gnu_longname; j > 0;
j--, ptr += T_BLOCKSIZE)
{
#ifdef DEBUG
printf(" th_read(): reading long filename "
"(%d blocks left, ptr == %ld)\n", j, ptr);
#endif
i = tar_block_read(t, ptr);
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
#ifdef DEBUG
printf(" th_read(): read block == \"%s\"\n", ptr);
#endif
}
#ifdef DEBUG
printf(" th_read(): t->th_buf.gnu_longname == \"%s\"\n",
t->th_buf.gnu_longname);
#endif
i = th_read_internal(t);
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
}
#if 0
/*
** work-around for old archive files with broken typeflag fields
** NOTE: I fixed this in the TH_IS*() macros instead
*/
/*
** (directories are signified with a trailing '/')
*/
if (t->th_buf.typeflag == AREGTYPE
&& t->th_buf.name[strlen(t->th_buf.name) - 1] == '/')
t->th_buf.typeflag = DIRTYPE;
/*
** fallback to using mode bits
*/
if (t->th_buf.typeflag == AREGTYPE)
{
mode = (mode_t)oct_to_int(t->th_buf.mode);
if (S_ISREG(mode))
t->th_buf.typeflag = REGTYPE;
else if (S_ISDIR(mode))
t->th_buf.typeflag = DIRTYPE;
else if (S_ISFIFO(mode))
t->th_buf.typeflag = FIFOTYPE;
else if (S_ISCHR(mode))
t->th_buf.typeflag = CHRTYPE;
else if (S_ISBLK(mode))
t->th_buf.typeflag = BLKTYPE;
else if (S_ISLNK(mode))
t->th_buf.typeflag = SYMTYPE;
}
#endif
return 0;
}
/* write a header block */
int
th_write(TAR *t)
{
ssize_t i, j;
char type2;
size_t sz, sz2;
char *ptr;
char buf[T_BLOCKSIZE];
#ifdef DEBUG
printf("==> th_write(TAR=\"%s\")\n", t->pathname);
th_print(t);
#endif
if ((t->options & TAR_GNU) && t->th_buf.gnu_longlink != NULL)
{
#ifdef DEBUG
printf("th_write(): using gnu_longlink (\"%s\")\n",
t->th_buf.gnu_longlink);
#endif
/* save old size and type */
type2 = t->th_buf.typeflag;
sz2 = th_get_size(t);
/* write out initial header block with fake size and type */
t->th_buf.typeflag = GNU_LONGLINK_TYPE;
sz = strlen(t->th_buf.gnu_longlink);
th_set_size(t, sz);
th_finish(t);
i = tar_block_write(t, &(t->th_buf));
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
/* write out extra blocks containing long name */
for (j = (sz / T_BLOCKSIZE) + (sz % T_BLOCKSIZE ? 1 : 0),
ptr = t->th_buf.gnu_longlink; j > 1;
j--, ptr += T_BLOCKSIZE)
{
i = tar_block_write(t, ptr);
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
}
memset(buf, 0, T_BLOCKSIZE);
strncpy(buf, ptr, T_BLOCKSIZE);
i = tar_block_write(t, &buf);
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
/* reset type and size to original values */
t->th_buf.typeflag = type2;
th_set_size(t, sz2);
}
if ((t->options & TAR_GNU) && t->th_buf.gnu_longname != NULL)
{
#ifdef DEBUG
printf("th_write(): using gnu_longname (\"%s\")\n",
t->th_buf.gnu_longname);
#endif
/* save old size and type */
type2 = t->th_buf.typeflag;
sz2 = th_get_size(t);
/* write out initial header block with fake size and type */
t->th_buf.typeflag = GNU_LONGNAME_TYPE;
sz = strlen(t->th_buf.gnu_longname);
th_set_size(t, sz);
th_finish(t);
i = tar_block_write(t, &(t->th_buf));
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
/* write out extra blocks containing long name */
for (j = (sz / T_BLOCKSIZE) + (sz % T_BLOCKSIZE ? 1 : 0),
ptr = t->th_buf.gnu_longname; j > 1;
j--, ptr += T_BLOCKSIZE)
{
i = tar_block_write(t, ptr);
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
}
memset(buf, 0, T_BLOCKSIZE);
strncpy(buf, ptr, T_BLOCKSIZE);
i = tar_block_write(t, &buf);
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
/* reset type and size to original values */
t->th_buf.typeflag = type2;
th_set_size(t, sz2);
}
th_finish(t);
#ifdef DEBUG
/* print tar header */
th_print(t);
#endif
i = tar_block_write(t, &(t->th_buf));
if (i != T_BLOCKSIZE)
{
if (i != -1)
errno = EINVAL;
return -1;
}
#ifdef DEBUG
puts("th_write(): returning 0");
#endif
return 0;
}
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