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| author | Tommi Rantala <tommi.t.rantala@nokia.com> | 2017-03-22 15:06:20 +0200 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2017-03-27 15:35:06 -0300 |
| commit | 5a2342111c68e623e27ee7ea3d0492d8dad6bda0 (patch) | |
| tree | 3611fafcd55cd24783aa5637384877eade08490d | |
| parent | 2ccc220238680642be87a2d010ce07f1c40edafb (diff) | |
| download | lwn-5a2342111c68e623e27ee7ea3d0492d8dad6bda0.tar.gz lwn-5a2342111c68e623e27ee7ea3d0492d8dad6bda0.zip | |
perf buildid: Do not assume that readlink() returns a null terminated string
Valgrind was complaining:
$ valgrind ./perf list >/dev/null
==11643== Memcheck, a memory error detector
==11643== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==11643== Using Valgrind-3.12.0 and LibVEX; rerun with -h for copyright info
==11643== Command: ./perf list
==11643==
==11643== Conditional jump or move depends on uninitialised value(s)
==11643== at 0x4C30620: rindex (vg_replace_strmem.c:199)
==11643== by 0x49DAA9: build_id_cache__origname (build-id.c:198)
==11643== by 0x49E1C7: build_id_cache__valid_id (build-id.c:222)
==11643== by 0x49E1C7: build_id_cache__list_all (build-id.c:507)
==11643== by 0x4B9C8F: print_sdt_events (parse-events.c:2067)
==11643== by 0x4BB0B3: print_events (parse-events.c:2313)
==11643== by 0x439501: cmd_list (builtin-list.c:53)
==11643== by 0x497150: run_builtin (perf.c:359)
==11643== by 0x428CE0: handle_internal_command (perf.c:421)
==11643== by 0x428CE0: run_argv (perf.c:467)
==11643== by 0x428CE0: main (perf.c:614)
[...]
Additionally, a zero length result from readlink() is not very interesting.
Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170322130624.21881-3-tommi.t.rantala@nokia.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| -rw-r--r-- | tools/perf/util/build-id.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c index 234859f756c4..33af67530d30 100644 --- a/tools/perf/util/build-id.c +++ b/tools/perf/util/build-id.c @@ -182,13 +182,17 @@ char *build_id_cache__origname(const char *sbuild_id) char buf[PATH_MAX]; char *ret = NULL, *p; size_t offs = 5; /* == strlen("../..") */ + ssize_t len; linkname = build_id_cache__linkname(sbuild_id, NULL, 0); if (!linkname) return NULL; - if (readlink(linkname, buf, PATH_MAX) < 0) + len = readlink(linkname, buf, sizeof(buf) - 1); + if (len <= 0) goto out; + buf[len] = '\0'; + /* The link should be "../..<origpath>/<sbuild_id>" */ p = strrchr(buf, '/'); /* Cut off the "/<sbuild_id>" */ if (p && (p > buf + offs)) { |