tools, perf: Add asprintf replacement

asprintf corrupts memory on some older glibc versions.
Provide a replacement. This fixes various segfaults
with --branch-history on older Fedoras.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

tools/perf/Makefile.perf

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 171f4e6..5bdb960 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -377,6 +377,7 @@
 LIB_OBJS += $(OUTPUT)util/stat.o
 LIB_OBJS += $(OUTPUT)util/record.o
 LIB_OBJS += $(OUTPUT)util/srcline.o
+LIB_OBJS += $(OUTPUT)util/asprintf.o
 LIB_OBJS += $(OUTPUT)util/data.o
 LIB_OBJS += $(OUTPUT)util/tsc.o
 LIB_OBJS += $(OUTPUT)util/cloexec.o

tools/perf/builtin-report.c

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index cd87a40..96bc166 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -756,7 +756,8 @@
 		callchain_param.branch_callstack = 1;
 		callchain_param.key = CCKEY_ADDRESS;
 		symbol_conf.use_callchain = true;
-		callchain_register_param(&callchain_param);
+		if (callchain_register_param(&callchain_param) < 0)
+			pr_err("Cannot register callchain parameters");
 		if (sort_order == default_sort_order)
 			sort_order = "srcline,symbol,dso";
 		branch_mode = 0;

tools/perf/util/asprintf.c

diff --git a/tools/perf/util/asprintf.c b/tools/perf/util/asprintf.c
new file mode 100644
index 0000000..9aafaca
--- /dev/null
+++ b/tools/perf/util/asprintf.c
@@ -0,0 +1,28 @@
+/* Replacement for asprintf as it's buggy in older glibc versions */
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+
+int vasprintf(char **str, const char *fmt, va_list ap)
+{
+	char buf[1024];
+	int len = vsnprintf(buf, sizeof buf, fmt, ap);
+
+	*str = malloc(len + 1);
+	if (!*str)
+		return -1;
+	strcpy(*str, buf);
+	return len;
+}
+
+int asprintf(char **str, const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = vasprintf(str, fmt, ap);
+	va_end(ap);
+	return ret;
+}