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Subject[tip:perf/hw-branch-sampling] perf tools: Fix ABI compatibility bug in print_event_desc()
Commit-ID:  62db90681c0db8c76e5db006b929a2edd5d12ae6
Gitweb: http://git.kernel.org/tip/62db90681c0db8c76e5db006b929a2edd5d12ae6
Author: Stephane Eranian <eranian@google.com>
AuthorDate: Thu, 9 Feb 2012 23:21:07 +0100
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 9 Mar 2012 08:26:06 +0100

perf tools: Fix ABI compatibility bug in print_event_desc()

This patches cleans up local variable types for msz and ret.
They need to be size_t and ssize_t respectively.

It also fixes a bug whereby perf would not read attr struct
with a different size than what it knows about.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-18-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
tools/perf/util/header.c | 19 +++++++++----------
1 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 666f189..6d58026 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1144,8 +1144,9 @@ static void print_event_desc(struct perf_header *ph, int fd, FILE *fp)
uint64_t id;
void *buf = NULL;
char *str;
- u32 nre, sz, nr, i, j, msz;
- int ret;
+ u32 nre, sz, nr, i, j;
+ ssize_t ret;
+ size_t msz;

/* number of events */
ret = read(fd, &nre, sizeof(nre));
@@ -1162,25 +1163,23 @@ static void print_event_desc(struct perf_header *ph, int fd, FILE *fp)
if (ph->needs_swap)
sz = bswap_32(sz);

- /*
- * ensure it is at least to our ABI rev
- */
- if (sz < (u32)sizeof(attr))
- goto error;
-
memset(&attr, 0, sizeof(attr));

- /* read entire region to sync up to next field */
+ /* buffer to hold on file attr struct */
buf = malloc(sz);
if (!buf)
goto error;

msz = sizeof(attr);
- if (sz < msz)
+ if (sz < (ssize_t)msz)
msz = sz;

for (i = 0 ; i < nre; i++) {

+ /*
+ * must read entire on-file attr struct to
+ * sync up with layout.
+ */
ret = read(fd, buf, sz);
if (ret != (ssize_t)sz)
goto error;

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