diff options
Diffstat (limited to 'lib/tdb/common/io.c')
| -rw-r--r-- | lib/tdb/common/io.c | 101 |
1 files changed, 89 insertions, 12 deletions
diff --git a/lib/tdb/common/io.c b/lib/tdb/common/io.c index 11dfefd102b..07d22ccdb21 100644 --- a/lib/tdb/common/io.c +++ b/lib/tdb/common/io.c @@ -28,6 +28,70 @@ #include "tdb_private.h" +/* + * tdb->hdr_ofs is 0 for now. + * + * Note: that we only have the 4GB limit of tdb_off_t for + * tdb->map_size. The file size on disk can be 4GB + tdb->hdr_ofs! + */ + +static bool tdb_adjust_offset(struct tdb_context *tdb, off_t *off) +{ + off_t tmp = tdb->hdr_ofs + *off; + + if ((tmp < tdb->hdr_ofs) || (tmp < *off)) { + errno = EIO; + return false; + } + + *off = tmp; + return true; +} + +static ssize_t tdb_pwrite(struct tdb_context *tdb, const void *buf, + size_t count, off_t offset) +{ + if (!tdb_adjust_offset(tdb, &offset)) { + return -1; + } + return pwrite(tdb->fd, buf, count, offset); +} + +static ssize_t tdb_pread(struct tdb_context *tdb, void *buf, + size_t count, off_t offset) +{ + if (!tdb_adjust_offset(tdb, &offset)) { + return -1; + } + return pread(tdb->fd, buf, count, offset); +} + +static int tdb_ftruncate(struct tdb_context *tdb, off_t length) +{ + if (!tdb_adjust_offset(tdb, &length)) { + return -1; + } + return ftruncate(tdb->fd, length); +} + +static int tdb_fstat(struct tdb_context *tdb, struct stat *buf) +{ + int ret; + + ret = fstat(tdb->fd, buf); + if (ret == -1) { + return -1; + } + + if (buf->st_size < tdb->hdr_ofs) { + errno = EIO; + return -1; + } + buf->st_size -= tdb->hdr_ofs; + + return ret; +} + /* check for an out of bounds access - if it is out of bounds then see if the database has been expanded by someone else and expand if necessary @@ -58,7 +122,7 @@ static int tdb_oob(struct tdb_context *tdb, tdb_off_t off, tdb_len_t len, return -1; } - if (fstat(tdb->fd, &st) == -1) { + if (tdb_fstat(tdb, &st) == -1) { tdb->ecode = TDB_ERR_IO; return -1; } @@ -122,16 +186,18 @@ static int tdb_write(struct tdb_context *tdb, tdb_off_t off, tdb->ecode = TDB_ERR_IO; return -1; #else - ssize_t written = pwrite(tdb->fd, buf, len, off); + ssize_t written; + + written = tdb_pwrite(tdb, buf, len, off); + if ((written != (ssize_t)len) && (written != -1)) { /* try once more */ tdb->ecode = TDB_ERR_IO; TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_write: wrote only " "%zi of %u bytes at %u, trying once more\n", written, len, off)); - written = pwrite(tdb->fd, (const char *)buf+written, - len-written, - off+written); + written = tdb_pwrite(tdb, (const char *)buf+written, + len-written, off+written); } if (written == -1) { /* Ensure ecode is set for log fn. */ @@ -176,7 +242,9 @@ static int tdb_read(struct tdb_context *tdb, tdb_off_t off, void *buf, tdb->ecode = TDB_ERR_IO; return -1; #else - ssize_t ret = pread(tdb->fd, buf, len, off); + ssize_t ret; + + ret = tdb_pread(tdb, buf, len, off); if (ret != (ssize_t)len) { /* Ensure ecode is set for log fn. */ tdb->ecode = TDB_ERR_IO; @@ -258,7 +326,8 @@ int tdb_mmap(struct tdb_context *tdb) if (should_mmap(tdb)) { tdb->map_ptr = mmap(NULL, tdb->map_size, PROT_READ|(tdb->read_only? 0:PROT_WRITE), - MAP_SHARED|MAP_FILE, tdb->fd, 0); + MAP_SHARED|MAP_FILE, tdb->fd, + tdb->hdr_ofs); /* * NB. When mmap fails it returns MAP_FAILED *NOT* NULL !!!! @@ -303,12 +372,12 @@ static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t ad return -1; } - if (ftruncate(tdb->fd, new_size) == -1) { + if (tdb_ftruncate(tdb, new_size) == -1) { char b = 0; - ssize_t written = pwrite(tdb->fd, &b, 1, new_size - 1); + ssize_t written = tdb_pwrite(tdb, &b, 1, new_size - 1); if (written == 0) { /* try once more, potentially revealing errno */ - written = pwrite(tdb->fd, &b, 1, new_size - 1); + written = tdb_pwrite(tdb, &b, 1, new_size - 1); } if (written == 0) { /* again - give up, guessing errno */ @@ -328,10 +397,10 @@ static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t ad memset(buf, TDB_PAD_BYTE, sizeof(buf)); while (addition) { size_t n = addition>sizeof(buf)?sizeof(buf):addition; - ssize_t written = pwrite(tdb->fd, buf, n, size); + ssize_t written = tdb_pwrite(tdb, buf, n, size); if (written == 0) { /* prevent infinite loops: try _once_ more */ - written = pwrite(tdb->fd, buf, n, size); + written = tdb_pwrite(tdb, buf, n, size); } if (written == 0) { /* give up, trying to provide a useful errno */ @@ -437,6 +506,14 @@ int tdb_expand(struct tdb_context *tdb, tdb_off_t size) /* must know about any previous expansions by another process */ tdb->methods->tdb_oob(tdb, tdb->map_size, 1, 1); + /* + * Note: that we don't care about tdb->hdr_ofs != 0 here + * + * The 4GB limitation is just related to tdb->map_size + * and the offset calculation in the records. + * + * The file on disk can be up to 4GB + tdb->hdr_ofs + */ size = tdb_expand_adjust(tdb->map_size, size, tdb->page_size); if (!tdb_add_off_t(tdb->map_size, size, &new_size)) { |