perf probe: Check the return value of strbuf APIs

Check the return value of strbuf APIs in perf-probe
related code, so that it can handle errors in strbuf.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20160510054707.6158.69861.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 24 insertions, 28 deletions

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index aea189b41cc8..a347b19c961a 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -915,8 +915,7 @@ int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
 		tmp = "*";
 	else if (tag == DW_TAG_subroutine_type) {
 		/* Function pointer */
-		strbuf_add(buf, "(function_type)", 15);
-		return 0;
+		return strbuf_add(buf, "(function_type)", 15);
 	} else {
 		if (!dwarf_diename(&type))
 			return -ENOENT;
@@ -927,14 +926,10 @@ int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
 		else if (tag == DW_TAG_enumeration_type)
 			tmp = "enum ";
 		/* Write a base name */
-		strbuf_addf(buf, "%s%s", tmp, dwarf_diename(&type));
-		return 0;
+		return strbuf_addf(buf, "%s%s", tmp, dwarf_diename(&type));
 	}
 	ret = die_get_typename(&type, buf);
-	if (ret == 0)
-		strbuf_addstr(buf, tmp);
-
-	return ret;
+	return ret ? ret : strbuf_addstr(buf, tmp);
 }
 
 /**
@@ -951,12 +946,10 @@ int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
 	ret = die_get_typename(vr_die, buf);
 	if (ret < 0) {
 		pr_debug("Failed to get type, make it unknown.\n");
-		strbuf_add(buf, " (unknown_type)", 14);
+		ret = strbuf_add(buf, " (unknown_type)", 14);
 	}
 
-	strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
-
-	return 0;
+	return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
 }
 
 #ifdef HAVE_DWARF_GETLOCATIONS
@@ -999,22 +992,24 @@ static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
 	}
 
 	while ((offset = dwarf_ranges(&scopes[1], offset, &base,
-				&start, &end)) > 0) {
+					&start, &end)) > 0) {
 		start -= entry;
 		end -= entry;
 
 		if (first) {
-			strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
-				name, start, end);
+			ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
+					  name, start, end);
 			first = false;
 		} else {
-			strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
-				start, end);
+			ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
+					  start, end);
 		}
+		if (ret < 0)
+			goto out;
 	}
 
 	if (!first)
-		strbuf_add(buf, "]>", 2);
+		ret = strbuf_add(buf, "]>", 2);
 
 out:
 	free(scopes);
@@ -1054,31 +1049,32 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
 	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 		return -EINVAL;
 
-	while ((offset = dwarf_getlocations(
-				&attr, offset, &base,
-				&start, &end, &op, &nops)) > 0) {
+	while ((offset = dwarf_getlocations(&attr, offset, &base,
+					&start, &end, &op, &nops)) > 0) {
 		if (start == 0) {
 			/* Single Location Descriptions */
 			ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
-			return ret;
+			goto out;
 		}
 
 		/* Location Lists */
 		start -= entry;
 		end -= entry;
 		if (first) {
-			strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
-				name, start, end);
+			ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
+					  name, start, end);
 			first = false;
 		} else {
-			strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
-				start, end);
+			ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
+					  start, end);
 		}
+		if (ret < 0)
+			goto out;
 	}
 
 	if (!first)
-		strbuf_add(buf, "]>", 2);
-
+		ret = strbuf_add(buf, "]>", 2);
+out:
 	return ret;
 }
 #else