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/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.
  */