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(read_and, list_archive): Simplify code.

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(read_header): Fix computation of signed checksums on machines where
char is unsigned.
Do not consider a block to be zero unless all its bytes are zero,
even the checksum bytes.  Do not attempt to parse the checksum of
a zero block.  Fix memory leak with long names and links.
(from_chars): Accommodate a buggy tar that outputs leading NUL
if the previous field overflows.
(skip_extended_headers): Don't assume find_next_block yields nonnull.
This commit is contained in:
Paul Eggert
1999-08-18 07:52:26 +00:00
parent 72290b64a6
commit c62fe41ec5
1 changed files with 41 additions and 89 deletions
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130
src/list.c
View File

@@ -55,7 +55,6 @@ read_and (void (*do_something) ())
{
enum read_header status = HEADER_STILL_UNREAD;
enum read_header prev_status;
char save_typeflag;
base64_init ();
name_gather ();
@@ -83,7 +82,7 @@ read_and (void (*do_something) ())
|| current_stat.st_mtime < newer_mtime_option
|| excluded_name (current_file_name))
{
int isextended = 0;
char save_typeflag;
if (current_header->header.typeflag == GNUTYPE_VOLHDR
|| current_header->header.typeflag == GNUTYPE_MULTIVOL
@@ -98,28 +97,10 @@ read_and (void (*do_something) ())
/* Skip past it in the archive. */
if (current_header->oldgnu_header.isextended)
isextended = 1;
save_typeflag = current_header->header.typeflag;
set_next_block_after (current_header);
if (isextended)
{
#if 0
union block *exhdr;
while (1)
{
exhdr = find_next_block ();
if (!exhdr->sparse_header.isextended)
{
set_next_block_after (exhdr);
break;
}
}
set_next_block_after (exhdr);
#endif
skip_extended_headers ();
}
if (current_header->oldgnu_header.isextended)
skip_extended_headers ();
/* Skip to the next header on the archive. */
@@ -191,8 +172,6 @@ read_and (void (*do_something) ())
void
list_archive (void)
{
int isextended = 0; /* to remember if current_header is extended */
/* Print the header block. */
if (verbose_option)
@@ -248,37 +227,11 @@ list_archive (void)
}
/* Check to see if we have an extended header to skip over also. */
if (current_header->oldgnu_header.isextended)
isextended = 1;
/* Skip past the header in the archive. */
/* Skip past the header in the archive, and past any extended headers. */
set_next_block_after (current_header);
/* If we needed to skip any extended headers, do so now, by reading
extended headers and skipping past them in the archive. */
if (isextended)
{
#if 0
union block *exhdr;
while (1)
{
exhdr = find_next_block ();
if (!exhdr->sparse_header.isextended)
{
set_next_block_after (exhdr);
break;
}
set_next_block_after (exhdr);
}
#endif
skip_extended_headers ();
}
if (current_header->oldgnu_header.isextended)
skip_extended_headers ();
if (multi_volume_option)
assign_string (&save_name, current_file_name);
@@ -312,16 +265,13 @@ list_archive (void)
a name containing characters with the high bit set. So read_header
computes two checksums -- signed and unsigned. */
/* FIXME: The signed checksum computation is broken on machines where char's
are unsigned. It's uneasy to handle all cases correctly... */
enum read_header
read_header (void)
{
size_t i;
long unsigned_sum; /* the POSIX one :-) */
long signed_sum; /* the Sun one :-( */
long recorded_sum;
int unsigned_sum; /* the POSIX one :-) */
int signed_sum; /* the Sun one :-( */
int recorded_sum;
uintmax_t parsed_sum;
char *p;
union block *header;
@@ -338,43 +288,36 @@ read_header (void)
if (!header)
return HEADER_END_OF_FILE;
parsed_sum = from_chars (header->header.chksum,
sizeof header->header.chksum,
(char *) 0, (uintmax_t) 0,
(uintmax_t) TYPE_MAXIMUM (long));
if (parsed_sum == (uintmax_t) -1)
return HEADER_FAILURE;
recorded_sum = parsed_sum;
unsigned_sum = 0;
signed_sum = 0;
p = header->buffer;
for (i = sizeof (*header); i-- != 0;)
{
/* We can't use unsigned char here because of old compilers,
e.g. V7. */
unsigned_sum += 0xFF & *p;
signed_sum += *p++;
unsigned_sum += (unsigned char) *p;
signed_sum += signed_char (*p++);
}
if (unsigned_sum == 0)
return HEADER_ZERO_BLOCK;
/* Adjust checksum to count the "chksum" field as blanks. */
for (i = sizeof (header->header.chksum); i-- != 0;)
{
unsigned_sum -= 0xFF & header->header.chksum[i];
signed_sum -= header->header.chksum[i];
unsigned_sum -= (unsigned char) header->header.chksum[i];
signed_sum -= signed_char (header->header.chksum[i]);
}
unsigned_sum += ' ' * sizeof header->header.chksum;
signed_sum += ' ' * sizeof header->header.chksum;
if (unsigned_sum == sizeof header->header.chksum * ' ')
{
/* This is a zeroed block...whole block is 0's except for the
blanks we faked for the checksum field. */
parsed_sum = from_chars (header->header.chksum,
sizeof header->header.chksum,
(char *) 0, (uintmax_t) 0,
(uintmax_t) TYPE_MAXIMUM (int));
if (parsed_sum == (uintmax_t) -1)
return HEADER_FAILURE;
return HEADER_ZERO_BLOCK;
}
recorded_sum = parsed_sum;
if (unsigned_sum != recorded_sum && signed_sum != recorded_sum)
return HEADER_FAILURE;
@@ -448,6 +391,11 @@ read_header (void)
name = namebuf;
}
assign_string (&current_file_name, name);
if (next_long_name)
{
free (next_long_name);
next_long_name = 0;
}
name = next_long_link;
if (! name)
@@ -457,8 +405,12 @@ read_header (void)
name = namebuf;
}
assign_string (&current_link_name, name);
if (next_long_link)
{
free (next_long_link);
next_long_link = 0;
}
next_long_link = next_long_name = 0;
return HEADER_SUCCESS;
}
}
@@ -560,17 +512,19 @@ from_chars (char const *where0, size_t digs, char const *type,
char const *lim = where + digs;
int negative = 0;
/* Accommodate older tars, which output leading spaces, and at least one
buggy tar, which outputs leading NUL if the previous field overflows. */
for (;;)
{
if (where == lim)
{
if (type)
ERROR ((0, 0,
_("Blanks in header where numeric %s value expected"),
_("Empty header where numeric %s value expected"),
type));
return -1;
}
if (!ISSPACE ((unsigned char) *where))
if (!ISSPACE ((unsigned char) *where) && *where)
break;
where++;
}
@@ -1123,14 +1077,12 @@ skip_extended_headers (void)
{
union block *exhdr;
while (1)
do
{
exhdr = find_next_block ();
if (!exhdr->sparse_header.isextended)
{
set_next_block_after (exhdr);
break;
}
if (!exhdr)
FATAL_ERROR ((0, 0, _("Unexpected EOF on archive file")));
set_next_block_after (exhdr);
}
while (exhdr->sparse_header.isextended);
}