perf symbols: Preparation for compressed kernel module support

This patch adds basic support to handle compressed kernel module as some
distro (such as Archlinux) carries on it now.  The actual work using
compression library will be added later.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1415063674-17206-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 34 insertions, 1 deletions

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 1e23a5bfb044..efc7eb6b8f0f 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -546,6 +546,35 @@ static int dso__swap_init(struct dso *dso, unsigned char eidata)
         return 0;
 }
 
+static int decompress_kmodule(struct dso *dso, const char *name,
+                              enum dso_binary_type type)
+{
+        int fd;
+        const char *ext = strrchr(name, '.');
+        char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
+
+        if ((type != DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP &&
+             type != DSO_BINARY_TYPE__GUEST_KMODULE_COMP) ||
+            type != dso->symtab_type)
+                return -1;
+
+        if (!ext || !is_supported_compression(ext + 1))
+                return -1;
+
+        fd = mkstemp(tmpbuf);
+        if (fd < 0)
+                return -1;
+
+        if (!decompress_to_file(ext + 1, name, fd)) {
+                close(fd);
+                fd = -1;
+        }
+
+        unlink(tmpbuf);
+
+        return fd;
+}
+
 bool symsrc__possibly_runtime(struct symsrc *ss)
 {
         return ss->dynsym || ss->opdsec;
@@ -571,7 +600,11 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
         Elf *elf;
         int fd;
 
-        fd = open(name, O_RDONLY);
+        if (dso__needs_decompress(dso))
+                fd = decompress_kmodule(dso, name, type);
+        else
+                fd = open(name, O_RDONLY);
+
         if (fd < 0)
                 return -1;