/*
* Parse key fields out of the header.
- *
- * FIXME: It's terrible that we use hard-coded values here instead of some
- * more principled approach. It's been like this for a long time, but we
- * ought to do better.
*/
- strlcpy(member->pathname, &buffer[0], MAXPGPATH);
+ strlcpy(member->pathname, &buffer[TAR_OFFSET_NAME], MAXPGPATH);
if (member->pathname[0] == '\0')
pg_fatal("tar member has empty name");
- member->size = read_tar_number(&buffer[124], 12);
- member->mode = read_tar_number(&buffer[100], 8);
- member->uid = read_tar_number(&buffer[108], 8);
- member->gid = read_tar_number(&buffer[116], 8);
- member->is_directory = (buffer[156] == '5');
- member->is_link = (buffer[156] == '2');
+ member->size = read_tar_number(&buffer[TAR_OFFSET_SIZE], 12);
+ member->mode = read_tar_number(&buffer[TAR_OFFSET_MODE], 8);
+ member->uid = read_tar_number(&buffer[TAR_OFFSET_UID], 8);
+ member->gid = read_tar_number(&buffer[TAR_OFFSET_GID], 8);
+ member->is_directory =
+ (buffer[TAR_OFFSET_TYPEFLAG] == TAR_FILETYPE_DIRECTORY);
+ member->is_link =
+ (buffer[TAR_OFFSET_TYPEFLAG] == TAR_FILETYPE_SYMLINK);
if (member->is_link)
- strlcpy(member->linktarget, &buffer[157], 100);
+ strlcpy(member->linktarget, &buffer[TAR_OFFSET_LINKNAME], 100);
/* Compute number of padding bytes. */
mystreamer->pad_bytes_expected = tarPaddingBytesRequired(member->size);
* possibly also renaming the file. We overwrite the entire current header
* when done, including the checksum.
*/
- print_tar_number(&(tf->header[124]), 12, filesize);
+ print_tar_number(&(tf->header[TAR_OFFSET_SIZE]), 12, filesize);
if (method == CLOSE_NORMAL)
* We overwrite it with what it was before if we have no tempname,
* since we're going to write the buffer anyway.
*/
- strlcpy(&(tf->header[0]), tf->base.pathname, 100);
+ strlcpy(&(tf->header[TAR_OFFSET_NAME]), tf->base.pathname, 100);
- print_tar_number(&(tf->header[148]), 8, tarChecksum(((TarMethodFile *) f)->header));
+ print_tar_number(&(tf->header[TAR_OFFSET_CHECKSUM]), 8,
+ tarChecksum(((TarMethodFile *) f)->header));
if (lseek(tar_data->fd, tf->ofs_start, SEEK_SET) != ((TarMethodFile *) f)->ofs_start)
{
f->wwmethod->lasterrno = errno;
int sum;
int chk = tarChecksum(header);
- sum = read_tar_number(&header[148], 8);
+ sum = read_tar_number(&header[TAR_OFFSET_CHECKSUM], 8);
if (sum != chk)
return false;
/* POSIX tar format */
- if (memcmp(&header[257], "ustar\0", 6) == 0 &&
- memcmp(&header[263], "00", 2) == 0)
+ if (memcmp(&header[TAR_OFFSET_MAGIC], "ustar\0", 6) == 0 &&
+ memcmp(&header[TAR_OFFSET_VERSION], "00", 2) == 0)
return true;
/* GNU tar format */
- if (memcmp(&header[257], "ustar \0", 8) == 0)
+ if (memcmp(&header[TAR_OFFSET_MAGIC], "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)
+ if (memcmp(&header[TAR_OFFSET_MAGIC], "ustar00\0", 8) == 0)
return true;
return false;
/* Calc checksum */
chk = tarChecksum(h);
- sum = read_tar_number(&h[148], 8);
+ sum = read_tar_number(&h[TAR_OFFSET_CHECKSUM], 8);
/*
* If the checksum failed, see if it is a null block. If so, silently
}
/* Name field is 100 bytes, might not be null-terminated */
- strlcpy(tag, &h[0], 100 + 1);
+ strlcpy(tag, &h[TAR_OFFSET_NAME], 100 + 1);
- len = read_tar_number(&h[124], 12);
+ len = read_tar_number(&h[TAR_OFFSET_SIZE], 12);
pg_log_debug("TOC Entry %s at %llu (length %llu, checksum %d)",
tag, (unsigned long long) hPos, (unsigned long long) len, sum);
TAR_SYMLINK_TOO_LONG
};
+/*
+ * Offsets of fields within a 512-byte tar header.
+ *
+ * "tar number" values should be generated using print_tar_number() and can be
+ * read using read_tar_number(). Fields that contain strings are generally
+ * both filled and read using strlcpy().
+ *
+ * The value for the checksum field can be computed using tarChecksum().
+ *
+ * Some fields are not used by PostgreSQL; see tarCreateHeader().
+ */
+enum tarHeaderOffset
+{
+ TAR_OFFSET_NAME = 0, /* 100 byte string */
+ TAR_OFFSET_MODE = 100, /* 8 byte tar number, excludes S_IFMT */
+ TAR_OFFSET_UID = 108, /* 8 byte tar number */
+ TAR_OFFSET_GID = 116, /* 8 byte tar number */
+ TAR_OFFSET_SIZE = 124, /* 8 byte tar number */
+ TAR_OFFSET_MTIME = 136, /* 12 byte tar number */
+ TAR_OFFSET_CHECKSUM = 148, /* 8 byte tar number */
+ TAR_OFFSET_TYPEFLAG = 156, /* 1 byte file type, see TAR_FILETYPE_* */
+ TAR_OFFSET_LINKNAME = 157, /* 100 byte string */
+ TAR_OFFSET_MAGIC = 257, /* "ustar" with terminating zero byte */
+ TAR_OFFSET_VERSION = 263, /* "00" */
+ TAR_OFFSET_UNAME = 265, /* 32 byte string */
+ TAR_OFFSET_GNAME = 297, /* 32 byte string */
+ TAR_OFFSET_DEVMAJOR = 329, /* 8 byte tar number */
+ TAR_OFFSET_DEVMINOR = 337, /* 8 byte tar number */
+ TAR_OFFSET_PREFIX = 345 /* 155 byte string */
+ /* last 12 bytes of the 512-byte block are unassigned */
+};
+
+enum tarFileType
+{
+ TAR_FILETYPE_PLAIN = '0',
+ TAR_FILETYPE_SYMLINK = '2',
+ TAR_FILETYPE_DIRECTORY = '5'
+};
+
extern enum tarError tarCreateHeader(char *h, const char *filename,
const char *linktarget, pgoff_t size,
mode_t mode, uid_t uid, gid_t gid,
if (linktarget && strlen(linktarget) > 99)
return TAR_SYMLINK_TOO_LONG;
- memset(h, 0, 512); /* assume tar header size */
+ memset(h, 0, TAR_BLOCK_SIZE);
/* Name 100 */
- strlcpy(&h[0], filename, 100);
+ strlcpy(&h[TAR_OFFSET_NAME], filename, 100);
if (linktarget != NULL || S_ISDIR(mode))
{
/*
}
/* Mode 8 - this doesn't include the file type bits (S_IFMT) */
- print_tar_number(&h[100], 8, (mode & 07777));
+ print_tar_number(&h[TAR_OFFSET_MODE], 8, (mode & 07777));
/* User ID 8 */
- print_tar_number(&h[108], 8, uid);
+ print_tar_number(&h[TAR_OFFSET_UID], 8, uid);
/* Group 8 */
- print_tar_number(&h[116], 8, gid);
+ print_tar_number(&h[TAR_OFFSET_GID], 8, gid);
/* File size 12 */
if (linktarget != NULL || S_ISDIR(mode))
/* Symbolic link or directory has size zero */
- print_tar_number(&h[124], 12, 0);
+ print_tar_number(&h[TAR_OFFSET_SIZE], 12, 0);
else
- print_tar_number(&h[124], 12, size);
+ print_tar_number(&h[TAR_OFFSET_SIZE], 12, size);
/* Mod Time 12 */
- print_tar_number(&h[136], 12, mtime);
+ print_tar_number(&h[TAR_OFFSET_MTIME], 12, mtime);
/* Checksum 8 cannot be calculated until we've filled all other fields */
if (linktarget != NULL)
{
/* Type - Symbolic link */
- h[156] = '2';
+ h[TAR_OFFSET_TYPEFLAG] = TAR_FILETYPE_SYMLINK;
/* Link Name 100 */
- strlcpy(&h[157], linktarget, 100);
+ strlcpy(&h[TAR_OFFSET_LINKNAME], linktarget, 100);
}
else if (S_ISDIR(mode))
{
/* Type - directory */
- h[156] = '5';
+ h[TAR_OFFSET_TYPEFLAG] = TAR_FILETYPE_DIRECTORY;
}
else
{
/* Type - regular file */
- h[156] = '0';
+ h[TAR_OFFSET_TYPEFLAG] = TAR_FILETYPE_PLAIN;
}
/* Magic 6 */
- strcpy(&h[257], "ustar");
+ strcpy(&h[TAR_OFFSET_MAGIC], "ustar");
/* Version 2 */
- memcpy(&h[263], "00", 2);
+ memcpy(&h[TAR_OFFSET_VERSION], "00", 2);
/* User 32 */
/* XXX: Do we need to care about setting correct username? */
- strlcpy(&h[265], "postgres", 32);
+ strlcpy(&h[TAR_OFFSET_UNAME], "postgres", 32);
/* Group 32 */
/* XXX: Do we need to care about setting correct group name? */
- strlcpy(&h[297], "postgres", 32);
+ strlcpy(&h[TAR_OFFSET_GNAME], "postgres", 32);
/* Major Dev 8 */
- print_tar_number(&h[329], 8, 0);
+ print_tar_number(&h[TAR_OFFSET_DEVMAJOR], 8, 0);
/* Minor Dev 8 */
- print_tar_number(&h[337], 8, 0);
+ print_tar_number(&h[TAR_OFFSET_DEVMINOR], 8, 0);
/* Prefix 155 - not used, leave as nulls */
/* Finally, compute and insert the checksum */
- print_tar_number(&h[148], 8, tarChecksum(h));
+ print_tar_number(&h[TAR_OFFSET_CHECKSUM], 8, tarChecksum(h));
return TAR_OK;
}
projects / postgresql.git / commitdiff