From 91e4a1760dee22e9a40ca52f1e5a1b549d9e066d Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 5 May 2010 15:37:18 +0930 Subject: [PATCH] tdb: fix short write logic in tdb_new_database Commit 207a213c/24fed55d purported to fix the problem of signals during tdb_new_database (which could cause a spurious short write, hence a failure). However, the code is wrong: newdb+written is not correct. Fix this by introducing a general tdb_write_all() and using it here and in the tracing code. Cc: Stefan Metzmacher Signed-off-by: Rusty Russell --- lib/tdb/common/open.c | 16 +--------------- lib/tdb/common/tdb.c | 16 +++++++++++++++- lib/tdb/common/tdb_private.h | 2 +- 3 files changed, 17 insertions(+), 17 deletions(-) diff --git a/lib/tdb/common/open.c b/lib/tdb/common/open.c index dfe780d21b7..3ff6b17c034 100644 --- a/lib/tdb/common/open.c +++ b/lib/tdb/common/open.c @@ -83,22 +83,8 @@ static int tdb_new_database(struct tdb_context *tdb, int hash_size) /* Don't endian-convert the magic food! */ memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1); /* we still have "ret == -1" here */ - written = write(tdb->fd, newdb, size); - if (written == size) { + if (tdb_write_all(tdb->fd, newdb, size)) ret = 0; - } else if (written != -1) { - /* call write once again, this usually should return -1 and - * set errno appropriately */ - size -= written; - written = write(tdb->fd, newdb+written, size); - if (written == size) { - ret = 0; - } else if (written >= 0) { - /* a second incomplete write - we give up. - * guessing the errno... */ - errno = ENOSPC; - } - } fail: SAFE_FREE(newdb); diff --git a/lib/tdb/common/tdb.c b/lib/tdb/common/tdb.c index dac3f4e6666..4d8c5fc59c9 100644 --- a/lib/tdb/common/tdb.c +++ b/lib/tdb/common/tdb.c @@ -989,10 +989,24 @@ int tdb_repack(struct tdb_context *tdb) return 0; } +/* Even on files, we can get partial writes due to signals. */ +bool tdb_write_all(int fd, const void *buf, size_t count) +{ + while (count) { + size_t ret; + ret = write(fd, buf, count); + if (ret < 0) + return false; + buf = (const char *)buf + ret; + count -= ret; + } + return true; +} + #ifdef TDB_TRACE static void tdb_trace_write(struct tdb_context *tdb, const char *str) { - if (write(tdb->tracefd, str, strlen(str)) != strlen(str)) { + if (!tdb_write_alltdb->tracefd, str, strlen(str)) { close(tdb->tracefd); tdb->tracefd = -1; } diff --git a/lib/tdb/common/tdb_private.h b/lib/tdb/common/tdb_private.h index e2167132b48..9d0f3bcd703 100644 --- a/lib/tdb/common/tdb_private.h +++ b/lib/tdb/common/tdb_private.h @@ -266,5 +266,5 @@ void tdb_io_init(struct tdb_context *tdb); int tdb_expand(struct tdb_context *tdb, tdb_off_t size); int tdb_rec_free_read(struct tdb_context *tdb, tdb_off_t off, struct tdb_record *rec); - +bool tdb_write_all(int fd, const void *buf, size_t count); int tdb_transaction_recover(struct tdb_context *tdb); -- 2.34.1