From: Paul Eggert Date: Wed, 18 Aug 1999 07:52:26 +0000 (+0000) Subject: (read_and, list_archive): Simplify code. X-Git-Url: https://git.dogcows.com/gitweb?a=commitdiff_plain;h=c62fe41ec532b78e737ba158ede0fe0a41439f95;p=chaz%2Ftar (read_and, list_archive): Simplify code. (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. --- diff --git a/src/list.c b/src/list.c index 1c24531..2109d8f 100644 --- a/src/list.c +++ b/src/list.c @@ -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 (¤t_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 (¤t_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); }