Read the 'magic' portion of 'struct blk_io_trace' first when reading the tracefile and only if all magic checks succeed, read the rest of the trace.
This is a preparation of supporting multiple trace protocol versions. Signed-off-by: Johannes Thumshirn <[email protected]> --- blkparse.c | 44 ++++++++++++++++++++++++++++++++++---------- 1 file changed, 34 insertions(+), 10 deletions(-) diff --git a/blkparse.c b/blkparse.c index d58322c..5645c31 100644 --- a/blkparse.c +++ b/blkparse.c @@ -2438,14 +2438,13 @@ static int read_events(int fd, int always_block, int *fdblock) struct trace *t; int pdu_len, should_block, ret; __u32 magic; - - bit = bit_alloc(); + void *p; should_block = !events || always_block; - ret = read_data(fd, bit, sizeof(*bit), should_block, fdblock); + ret = read_data(fd, &magic, sizeof(magic), should_block, + fdblock); if (ret) { - bit_free(bit); if (!events && ret < 0) events = ret; break; @@ -2455,15 +2454,28 @@ static int read_events(int fd, int always_block, int *fdblock) * look at first trace to check whether we need to convert * data in the future */ - if (data_is_native == -1 && check_data_endianness(bit->magic)) + if (data_is_native == -1 && check_data_endianness(magic)) break; - magic = get_magic(bit->magic); + magic = get_magic(magic); if ((magic & 0xffffff00) != BLK_IO_TRACE_MAGIC) { fprintf(stderr, "Bad magic %x\n", magic); break; } + bit = bit_alloc(); + bit->magic = magic; + p = (void *) ((u8 *)bit + sizeof(magic)); + + ret = read_data(fd, p, sizeof(*bit) - sizeof(magic), + should_block, fdblock); + if (ret) { + bit_free(bit); + if (!events && ret < 0) + events = ret; + break; + } + pdu_len = get_pdulen(bit); if (pdu_len) { void *ptr = realloc(bit, sizeof(*bit) + pdu_len); @@ -2596,20 +2608,30 @@ static int ms_prime(struct ms_stream *msp) int ret, pdu_len, ndone = 0; for (i = 0; !is_done() && pci->fd >= 0 && i < rb_batch; i++) { - bit = bit_alloc(); - ret = read_data(pci->fd, bit, sizeof(*bit), 1, &pci->fdblock); + void *p; + + ret = read_data(pci->fd, &magic, sizeof(magic), 1, + &pci->fdblock); if (ret) goto err; - if (data_is_native == -1 && check_data_endianness(bit->magic)) + if (data_is_native == -1 && check_data_endianness(magic)) goto err; - magic = get_magic(bit->magic); + magic = get_magic(magic); if ((magic & 0xffffff00) != BLK_IO_TRACE_MAGIC) { fprintf(stderr, "Bad magic %x\n", magic); goto err; } + bit = bit_alloc(); + bit->magic = magic; + p = (void *) ((u8 *)bit + sizeof(magic)); + + ret = read_data(pci->fd, p, sizeof(*bit) - sizeof(magic), 1, + &pci->fdblock); + if (ret) + goto err; pdu_len = get_pdulen(bit); if (pdu_len) { @@ -2639,6 +2661,7 @@ static int ms_prime(struct ms_stream *msp) handle_notify(bit); output_binary(bit, sizeof(*bit) + bit->pdu_len); bit_free(bit); + bit = NULL; i -= 1; continue; @@ -2659,6 +2682,7 @@ static int ms_prime(struct ms_stream *msp) } ndone++; + bit = NULL; } return ndone; -- 2.51.0
