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>

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 666f189..6d58026 100644 (file)
--- 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;