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From:   Jiri Olsa <jolsa@kernel.org>
To:     Arnaldo Carvalho de Melo <acme@kernel.org>
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        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Ingo Molnar <mingo@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Michael Petlan <mpetlan@redhat.com>,
        Song Liu <songliubraving@fb.com>,
        "Frank Ch. Eigler" <fche@redhat.com>,
        Ian Rogers <irogers@google.com>,
        Stephane Eranian <eranian@google.com>,
        Alexey Budankov <alexey.budankov@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Adrian Hunter <adrian.hunter@intel.com>
Subject: [PATCH 07/26] perf tools: Add check for existing link in buildid dir
Date:   Sun, 13 Sep 2020 23:02:54 +0200
Message-Id: <20200913210313.1985612-8-jolsa@kernel.org>
In-Reply-To: <20200913210313.1985612-1-jolsa@kernel.org>
References: <20200913210313.1985612-1-jolsa@kernel.org>
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When adding new build id link we fail if the link is already
there. Adding check for existing link and warn/replace the
link with new target.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/util/build-id.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index bdee4e08e60d..ecdc167aa1a0 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -751,8 +751,26 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
 	tmp = dir_name + strlen(buildid_dir) - 5;
 	memcpy(tmp, "../..", 5);
 
-	if (symlink(tmp, linkname) == 0)
+	if (symlink(tmp, linkname) == 0) {
 		err = 0;
+	} else if (errno == EEXIST) {
+		char path[PATH_MAX];
+
+		if (readlink(linkname, path, sizeof(path)) == -1) {
+			pr_err("Cant read link: %s\n", linkname);
+			goto out_free;
+		}
+		if (strcmp(tmp, path)) {
+			pr_err("Inconsistent .debug record, updating [%s]\n",
+				linkname);
+
+			unlink(linkname);
+
+			if (symlink(tmp, linkname))
+				goto out_free;
+		}
+		err = 0;
+	}
 
 	/* Update SDT cache : error is just warned */
 	if (realname &&
-- 
2.26.2