perf tools: Add filename__decompress function

Factor filename__decompress from decompress_kmodule function.  It can
decompress files with compressions supported in perf - xz and gz, the
support needs to be compiled in.

It will to be used in following changes to get build id out of
compressed elf objects.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20201126170026.2619053-9-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 19 insertions, 12 deletions

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 89b5fd2b5de3..d786cf6b0cfa 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -279,18 +279,12 @@ bool dso__needs_decompress(struct dso *dso)
 		dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE_COMP;
 }
 
-static int decompress_kmodule(struct dso *dso, const char *name,
-			      char *pathname, size_t len)
+int filename__decompress(const char *name, char *pathname,
+			 size_t len, int comp, int *err)
 {
 	char tmpbuf[] = KMOD_DECOMP_NAME;
 	int fd = -1;
 
-	if (!dso__needs_decompress(dso))
-		return -1;
-
-	if (dso->comp == COMP_ID__NONE)
-		return -1;
-
 	/*
 	 * We have proper compression id for DSO and yet the file
 	 * behind the 'name' can still be plain uncompressed object.
@@ -304,17 +298,17 @@ static int decompress_kmodule(struct dso *dso, const char *name,
 	 * To keep this transparent, we detect this and return the file
 	 * descriptor to the uncompressed file.
 	 */
-	if (!compressions[dso->comp].is_compressed(name))
+	if (!compressions[comp].is_compressed(name))
 		return open(name, O_RDONLY);
 
 	fd = mkstemp(tmpbuf);
 	if (fd < 0) {
-		dso->load_errno = errno;
+		*err = errno;
 		return -1;
 	}
 
-	if (compressions[dso->comp].decompress(name, fd)) {
-		dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
+	if (compressions[comp].decompress(name, fd)) {
+		*err = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
 		close(fd);
 		fd = -1;
 	}
@@ -328,6 +322,19 @@ static int decompress_kmodule(struct dso *dso, const char *name,
 	return fd;
 }
 
+static int decompress_kmodule(struct dso *dso, const char *name,
+			      char *pathname, size_t len)
+{
+	if (!dso__needs_decompress(dso))
+		return -1;
+
+	if (dso->comp == COMP_ID__NONE)
+		return -1;
+
+	return filename__decompress(name, pathname, len, dso->comp,
+				    &dso->load_errno);
+}
+
 int dso__decompress_kmodule_fd(struct dso *dso, const char *name)
 {
 	return decompress_kmodule(dso, name, NULL, 0);