diff options
Diffstat (limited to 'src/bin/pg_dump/pg_backup_tar.c')
| -rw-r--r-- | src/bin/pg_dump/pg_backup_tar.c | 87 |
1 files changed, 53 insertions, 34 deletions
diff --git a/src/bin/pg_dump/pg_backup_tar.c b/src/bin/pg_dump/pg_backup_tar.c index ced5c13321e..34d2c1a0df5 100644 --- a/src/bin/pg_dump/pg_backup_tar.c +++ b/src/bin/pg_dump/pg_backup_tar.c @@ -882,8 +882,10 @@ _CloseArchive(ArchiveHandle *AH) tarClose(AH, th); - /* Add a block of NULLs since it's de-rigeur. */ - for (i = 0; i < 512; i++) + /* + * EOF marker for tar files is two blocks of NULLs. + */ + for (i = 0; i < 512 * 2; i++) { if (fputc(0, ctx->tarFH) == EOF) exit_horribly(modulename, @@ -1032,11 +1034,16 @@ _tarChecksum(char *header) int i, sum; - sum = 0; + /* + * Per POSIX, the checksum is the simple sum of all bytes in the header, + * treating the bytes as unsigned, and treating the checksum field (at + * offset 148) as though it contained 8 spaces. + */ + sum = 8 * ' '; /* presumed value for checksum field */ for (i = 0; i < 512; i++) if (i < 148 || i >= 156) sum += 0xFF & header[i]; - return sum + 256; /* Assume 8 blanks in checksum field */ + return sum; } bool @@ -1050,11 +1057,15 @@ isValidTarHeader(char *header) if (sum != chk) return false; - /* POSIX format */ - if (strncmp(&header[257], "ustar00", 7) == 0) + /* POSIX tar format */ + if (memcmp(&header[257], "ustar\0", 6) == 0 && + memcmp(&header[263], "00", 2) == 0) return true; - /* older format */ - if (strncmp(&header[257], "ustar ", 7) == 0) + /* GNU tar format */ + if (memcmp(&header[257], "ustar \0", 8) == 0) + return true; + /* not-quite-POSIX format written by pre-9.3 pg_dump */ + if (memcmp(&header[257], "ustar00\0", 8) == 0) return true; return false; @@ -1329,63 +1340,71 @@ static void _tarWriteHeader(TAR_MEMBER *th) { char h[512]; - int lastSum = 0; - int sum; + /* + * Note: most of the fields in a tar header are not supposed to be + * null-terminated. We use sprintf, which will write a null after the + * required bytes; that null goes into the first byte of the next field. + * This is okay as long as we fill the fields in order. + */ memset(h, 0, sizeof(h)); /* Name 100 */ sprintf(&h[0], "%.99s", th->targetFile); /* Mode 8 */ - sprintf(&h[100], "100600 "); + sprintf(&h[100], "0000600 "); /* User ID 8 */ - sprintf(&h[108], "004000 "); + sprintf(&h[108], "0004000 "); /* Group 8 */ - sprintf(&h[116], "002000 "); + sprintf(&h[116], "0002000 "); - /* File size 12 - 11 digits, 1 space, no NUL */ + /* File size 12 - 11 digits, 1 space; use print_val for 64 bit support */ print_val(&h[124], th->fileLen, 8, 11); sprintf(&h[135], " "); /* Mod Time 12 */ sprintf(&h[136], "%011o ", (int) time(NULL)); - /* Checksum 8 */ - sprintf(&h[148], "%06o ", lastSum); + /* Checksum 8 cannot be calculated until we've filled all other fields */ /* Type - regular file */ sprintf(&h[156], "0"); - /* Link tag 100 (NULL) */ + /* Link Name 100 (leave as nulls) */ - /* Magic 6 + Version 2 */ - sprintf(&h[257], "ustar00"); + /* Magic 6 */ + sprintf(&h[257], "ustar"); + + /* Version 2 */ + sprintf(&h[263], "00"); -#if 0 /* User 32 */ - sprintf(&h[265], "%.31s", ""); /* How do I get username reliably? Do - * I need to? */ + /* XXX: Do we need to care about setting correct username? */ + sprintf(&h[265], "%.31s", "postgres"); /* Group 32 */ - sprintf(&h[297], "%.31s", ""); /* How do I get group reliably? Do I - * need to? */ + /* XXX: Do we need to care about setting correct group name? */ + sprintf(&h[297], "%.31s", "postgres"); - /* Maj Dev 8 */ - sprintf(&h[329], "%6o ", 0); + /* Major Dev 8 */ + sprintf(&h[329], "%07o ", 0); - /* Min Dev 8 */ - sprintf(&h[337], "%6o ", 0); -#endif + /* Minor Dev 8 */ + sprintf(&h[337], "%07o ", 0); - while ((sum = _tarChecksum(h)) != lastSum) - { - sprintf(&h[148], "%06o ", sum); - lastSum = sum; - } + /* Prefix 155 - not used, leave as nulls */ + + /* + * We mustn't overwrite the next field while inserting the checksum. + * Fortunately, the checksum can't exceed 6 octal digits, so we just write + * 6 digits, a space, and a null, which is legal per POSIX. + */ + sprintf(&h[148], "%06o ", _tarChecksum(h)); + /* Now write the completed header. */ if (fwrite(h, 1, 512, th->tarFH) != 512) exit_horribly(modulename, "could not write to output file: %s\n", strerror(errno)); } |