perf tools: Add kmod_path__parse function

Provides united way of parsing kernel module path
into several components.

The new kmod_path__parse function and few defines:

  int __kmod_path__parse(struct kmod_path *m, const char *path,
                         bool alloc_name, bool alloc_ext);

  #define kmod_path__parse(__m, __p)      __kmod_path__parse(__m, __p, false, false)
  #define kmod_path__parse_name(__m, __p) __kmod_path__parse(__m, __p, true , false)
  #define kmod_path__parse_ext(__m, __p)  __kmod_path__parse(__m, __p, false, true)

parse kernel module @path and updates @m argument like:

  @comp - true if @path contains supported compression suffix,
          false otherwise
  @kmod - true if @path contains '.ko' suffix in right position,
          false otherwise
  @name - if (@alloc_name && @kmod) is true, it contains strdup-ed base name
          of the kernel module without suffixes, otherwise strudup-ed
          base name of @path
  @ext  - if (@alloc_ext && @comp) is true, it contains strdup-ed string
          the compression suffix

It returns 0 if there's no strdup error, -ENOMEM otherwise.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.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/n/tip-9t6eqg8j610r94l743hkntiv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/Build

@@ -30,6 +30,7 @@ perf-y += keep-tracking.o
 perf-y += code-reading.o
 perf-y += sample-parsing.o
 perf-y += parse-no-sample-id-all.o
+perf-y += kmod-path.o
 
 perf-$(CONFIG_X86) += perf-time-to-tsc.o
 

tools/perf/tests/builtin-test.c

@@ -166,6 +166,10 @@ static struct test {
 		.desc = "Add fd to a fdarray, making it autogrow",
 		.func = test__fdarray__add,
 	},
+	{
+		.desc = "Test kmod_path__parse function",
+		.func = test__kmod_path__parse,
+	},
 	{
 		.func = NULL,
 	},

tools/perf/tests/kmod-path.c

@@ -0,0 +1,73 @@
+#include <stdbool.h>
+#include "tests.h"
+#include "dso.h"
+#include "debug.h"
+
+static int test(const char *path, bool alloc_name, bool alloc_ext,
+		bool kmod, bool comp, const char *name, const char *ext)
+{
+	struct kmod_path m;
+
+	memset(&m, 0x0, sizeof(m));
+
+	TEST_ASSERT_VAL("kmod_path__parse",
+			!__kmod_path__parse(&m, path, alloc_name, alloc_ext));
+
+	pr_debug("%s - alloc name %d, alloc ext %d, kmod %d, comp %d, name '%s', ext '%s'\n",
+		 path, alloc_name, alloc_ext, m.kmod, m.comp, m.name, m.ext);
+
+	TEST_ASSERT_VAL("wrong kmod", m.kmod == kmod);
+	TEST_ASSERT_VAL("wrong comp", m.comp == comp);
+
+	if (ext)
+		TEST_ASSERT_VAL("wrong ext", m.ext && !strcmp(ext, m.ext));
+	else
+		TEST_ASSERT_VAL("wrong ext", !m.ext);
+
+	if (name)
+		TEST_ASSERT_VAL("wrong name", m.name && !strcmp(name, m.name));
+	else
+		TEST_ASSERT_VAL("wrong name", !m.name);
+
+	free(m.name);
+	free(m.ext);
+	return 0;
+}
+
+#define T(path, an, ae, k, c, n, e) \
+	TEST_ASSERT_VAL("failed", !test(path, an, ae, k, c, n, e))
+
+int test__kmod_path__parse(void)
+{
+	/* path                alloc_name  alloc_ext   kmod  comp   name     ext */
+	T("/xxxx/xxxx/x-x.ko", true      , true      , true, false, "[x_x]", NULL);
+	T("/xxxx/xxxx/x-x.ko", false     , true      , true, false, NULL   , NULL);
+	T("/xxxx/xxxx/x-x.ko", true      , false     , true, false, "[x_x]", NULL);
+	T("/xxxx/xxxx/x-x.ko", false     , false     , true, false, NULL   , NULL);
+
+	/* path                alloc_name  alloc_ext   kmod  comp  name   ext */
+	T("/xxxx/xxxx/x.ko.gz", true     , true      , true, true, "[x]", "gz");
+	T("/xxxx/xxxx/x.ko.gz", false    , true      , true, true, NULL , "gz");
+	T("/xxxx/xxxx/x.ko.gz", true     , false     , true, true, "[x]", NULL);
+	T("/xxxx/xxxx/x.ko.gz", false    , false     , true, true, NULL , NULL);
+
+	/* path              alloc_name  alloc_ext  kmod   comp  name    ext */
+	T("/xxxx/xxxx/x.gz", true      , true     , false, true, "x.gz" ,"gz");
+	T("/xxxx/xxxx/x.gz", false     , true     , false, true, NULL   ,"gz");
+	T("/xxxx/xxxx/x.gz", true      , false    , false, true, "x.gz" , NULL);
+	T("/xxxx/xxxx/x.gz", false     , false    , false, true, NULL   , NULL);
+
+	/* path   alloc_name  alloc_ext  kmod   comp  name     ext */
+	T("x.gz", true      , true     , false, true, "x.gz", "gz");
+	T("x.gz", false     , true     , false, true, NULL  , "gz");
+	T("x.gz", true      , false    , false, true, "x.gz", NULL);
+	T("x.gz", false     , false    , false, true, NULL  , NULL);
+
+	/* path      alloc_name  alloc_ext  kmod  comp  name  ext */
+	T("x.ko.gz", true      , true     , true, true, "[x]", "gz");
+	T("x.ko.gz", false     , true     , true, true, NULL , "gz");
+	T("x.ko.gz", true      , false    , true, true, "[x]", NULL);
+	T("x.ko.gz", false     , false    , true, true, NULL , NULL);
+
+	return 0;
+}

tools/perf/tests/tests.h

@@ -51,6 +51,7 @@ int test__hists_cumulate(void);
 int test__switch_tracking(void);
 int test__fdarray__filter(void);
 int test__fdarray__add(void);
+int test__kmod_path__parse(void);
 
 #if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
 #ifdef HAVE_DWARF_UNWIND_SUPPORT

tools/perf/util/dso.c

@@ -211,6 +211,72 @@ bool dso__needs_decompress(struct dso *dso)
 		dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE_COMP;
 }
 
+/*
+ * Parses kernel module specified in @path and updates
+ * @m argument like:
+ *
+ *    @comp - true if @path contains supported compression suffix,
+ *            false otherwise
+ *    @kmod - true if @path contains '.ko' suffix in right position,
+ *            false otherwise
+ *    @name - if (@alloc_name && @kmod) is true, it contains strdup-ed base name
+ *            of the kernel module without suffixes, otherwise strudup-ed
+ *            base name of @path
+ *    @ext  - if (@alloc_ext && @comp) is true, it contains strdup-ed string
+ *            the compression suffix
+ *
+ * Returns 0 if there's no strdup error, -ENOMEM otherwise.
+ */
+int __kmod_path__parse(struct kmod_path *m, const char *path,
+		       bool alloc_name, bool alloc_ext)
+{
+	const char *name = strrchr(path, '/');
+	const char *ext  = strrchr(path, '.');
+
+	memset(m, 0x0, sizeof(*m));
+	name = name ? name + 1 : path;
+
+	/* No extension, just return name. */
+	if (ext == NULL) {
+		if (alloc_name) {
+			m->name = strdup(name);
+			return m->name ? 0 : -ENOMEM;
+		}
+		return 0;
+	}
+
+	if (is_supported_compression(ext + 1)) {
+		m->comp = true;
+		ext -= 3;
+	}
+
+	/* Check .ko extension only if there's enough name left. */
+	if (ext > name)
+		m->kmod = !strncmp(ext, ".ko", 3);
+
+	if (alloc_name) {
+		if (m->kmod) {
+			if (asprintf(&m->name, "[%.*s]", (int) (ext - name), name) == -1)
+				return -ENOMEM;
+		} else {
+			if (asprintf(&m->name, "%s", name) == -1)
+				return -ENOMEM;
+		}
+
+		strxfrchar(m->name, '-', '_');
+	}
+
+	if (alloc_ext && m->comp) {
+		m->ext = strdup(ext + 4);
+		if (!m->ext) {
+			free((void *) m->name);
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
 /*
  * Global list of open DSOs and the counter.
  */

tools/perf/util/dso.h

@@ -195,6 +195,20 @@ bool is_kernel_module(const char *pathname, bool *compressed);
 bool decompress_to_file(const char *ext, const char *filename, int output_fd);
 bool dso__needs_decompress(struct dso *dso);
 
+struct kmod_path {
+	char *name;
+	char *ext;
+	bool  comp;
+	bool  kmod;
+};
+
+int __kmod_path__parse(struct kmod_path *m, const char *path,
+		     bool alloc_name, bool alloc_ext);
+
+#define kmod_path__parse(__m, __p)      __kmod_path__parse(__m, __p, false, false)
+#define kmod_path__parse_name(__m, __p) __kmod_path__parse(__m, __p, true , false)
+#define kmod_path__parse_ext(__m, __p)  __kmod_path__parse(__m, __p, false, true)
+
 /*
  * The dso__data_* external interface provides following functions:
  *   dso__data_fd