perf annotate: Factor out get/free_srcline()

Currently external addr2line tool is used for srcline sort key and
annotate with srcline info.  Separate the common code to prepare
upcoming enhancements.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1378876173-13363-5-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/srcline.c

@@ -0,0 +1,83 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <linux/kernel.h>
+
+#include "util/util.h"
+#include "util/debug.h"
+
+static int addr2line(const char *dso_name, unsigned long addr,
+		     char **file, unsigned int *line_nr)
+{
+	FILE *fp;
+	char cmd[PATH_MAX];
+	char *filename = NULL;
+	size_t len;
+	char *sep;
+	int ret = 0;
+
+	scnprintf(cmd, sizeof(cmd), "addr2line -e %s %016"PRIx64,
+		  dso_name, addr);
+
+	fp = popen(cmd, "r");
+	if (fp == NULL) {
+		pr_warning("popen failed for %s\n", dso_name);
+		return 0;
+	}
+
+	if (getline(&filename, &len, fp) < 0 || !len) {
+		pr_warning("addr2line has no output for %s\n", dso_name);
+		goto out;
+	}
+
+	sep = strchr(filename, '\n');
+	if (sep)
+		*sep = '\0';
+
+	if (!strcmp(filename, "??:0")) {
+		pr_debug("no debugging info in %s\n", dso_name);
+		free(filename);
+		goto out;
+	}
+
+	sep = strchr(filename, ':');
+	if (sep) {
+		*sep++ = '\0';
+		*file = filename;
+		*line_nr = strtoul(sep, NULL, 0);
+		ret = 1;
+	}
+out:
+	pclose(fp);
+	return ret;
+}
+
+char *get_srcline(const char *dso_name, unsigned long addr)
+{
+	char *file;
+	unsigned line;
+	char *srcline;
+	size_t size;
+
+	if (!addr2line(dso_name, addr, &file, &line))
+		return SRCLINE_UNKNOWN;
+
+	/* just calculate actual length */
+	size = snprintf(NULL, 0, "%s:%u", file, line) + 1;
+
+	srcline = malloc(size);
+	if (srcline)
+		snprintf(srcline, size, "%s:%u", file, line);
+	else
+		srcline = SRCLINE_UNKNOWN;
+
+	free(file);
+	return srcline;
+}
+
+void free_srcline(char *srcline)
+{
+	if (srcline && strcmp(srcline, SRCLINE_UNKNOWN) != 0)
+		free(srcline);
+}