6 files changed, 28 insertions, 6 deletions
diff --git a/tools/lib/api/Build b/tools/lib/api/Build
index 954c644f7ad9..6e2373db5598 100644
--- a/tools/lib/api/Build
+++ b/tools/lib/api/Build
@@ -2,3 +2,8 @@ libapi-y += fd/
 libapi-y += fs/
 libapi-y += cpu.o
 libapi-y += debug.o
+libapi-y += str_error_r.o
+
+$(OUTPUT)str_error_r.o: ../str_error_r.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_o_c)
diff --git a/tools/lib/api/Makefile b/tools/lib/api/Makefile
index 316f308a63ea..0a6fda9837f7 100644
--- a/tools/lib/api/Makefile
+++ b/tools/lib/api/Makefile
@@ -10,15 +10,23 @@ endif
 
 CC = $(CROSS_COMPILE)gcc
 AR = $(CROSS_COMPILE)ar
+LD = $(CROSS_COMPILE)ld
 
 MAKEFLAGS += --no-print-directory
 
 LIBFILE = $(OUTPUT)libapi.a
 
 CFLAGS := $(EXTRA_WARNINGS) $(EXTRA_CFLAGS)
-CFLAGS += -ggdb3 -Wall -Wextra -std=gnu99 -Werror -O6 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fPIC
+CFLAGS += -ggdb3 -Wall -Wextra -std=gnu99 -O6 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fPIC
+
+# Treat warnings as errors unless directed not to
+ifneq ($(WERROR),0)
+  CFLAGS += -Werror
+endif
+
 CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
 CFLAGS += -I$(srctree)/tools/lib/api
+CFLAGS += -I$(srctree)/tools/include
 
 RM = rm -f
 
diff --git a/tools/lib/api/fd/array.c b/tools/lib/api/fd/array.c
index 0e636c4339b8..b0a035fc87b3 100644
--- a/tools/lib/api/fd/array.c
+++ b/tools/lib/api/fd/array.c
@@ -85,7 +85,8 @@ int fdarray__add(struct fdarray *fda, int fd, short revents)
 }
 
 int fdarray__filter(struct fdarray *fda, short revents,
-		    void (*entry_destructor)(struct fdarray *fda, int fd))
+		    void (*entry_destructor)(struct fdarray *fda, int fd, void *arg),
+		    void *arg)
 {
 	int fd, nr = 0;
 
@@ -95,7 +96,7 @@ int fdarray__filter(struct fdarray *fda, short revents,
 	for (fd = 0; fd < fda->nr; ++fd) {
 		if (fda->entries[fd].revents & revents) {
 			if (entry_destructor)
-				entry_destructor(fda, fd);
+				entry_destructor(fda, fd, arg);
 
 			continue;
 		}
diff --git a/tools/lib/api/fd/array.h b/tools/lib/api/fd/array.h
index 45db01818f45..71287dddc05f 100644
--- a/tools/lib/api/fd/array.h
+++ b/tools/lib/api/fd/array.h
@@ -22,6 +22,7 @@ struct fdarray {
 	struct pollfd *entries;
 	union {
 		int    idx;
+		void   *ptr;
 	} *priv;
 };
 
@@ -34,7 +35,8 @@ void fdarray__delete(struct fdarray *fda);
 int fdarray__add(struct fdarray *fda, int fd, short revents);
 int fdarray__poll(struct fdarray *fda, int timeout);
 int fdarray__filter(struct fdarray *fda, short revents,
-		    void (*entry_destructor)(struct fdarray *fda, int fd));
+		    void (*entry_destructor)(struct fdarray *fda, int fd, void *arg),
+		    void *arg);
 int fdarray__grow(struct fdarray *fda, int extra);
 int fdarray__fprintf(struct fdarray *fda, FILE *fp);
 
diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
index 08556cf2c70d..ba7094b945ff 100644
--- a/tools/lib/api/fs/fs.c
+++ b/tools/lib/api/fs/fs.c
@@ -283,6 +283,11 @@ int filename__read_int(const char *filename, int *value)
 	return err;
 }
 
+/*
+ * Parses @value out of @filename with strtoull.
+ * By using 0 for base, the strtoull detects the
+ * base automatically (see man strtoull).
+ */
 int filename__read_ull(const char *filename, unsigned long long *value)
 {
 	char line[64];
@@ -292,7 +297,7 @@ int filename__read_ull(const char *filename, unsigned long long *value)
 		return -1;
 
 	if (read(fd, line, sizeof(line)) > 0) {
-		*value = strtoull(line, NULL, 10);
+		*value = strtoull(line, NULL, 0);
 		if (*value != ULLONG_MAX)
 			err = 0;
 	}
diff --git a/tools/lib/api/fs/tracing_path.c b/tools/lib/api/fs/tracing_path.c
index a26bb5ea8283..251b7c342a87 100644
--- a/tools/lib/api/fs/tracing_path.c
+++ b/tools/lib/api/fs/tracing_path.c
@@ -5,6 +5,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <linux/string.h>
 #include <errno.h>
 #include <unistd.h>
 #include "fs.h"
@@ -118,7 +119,7 @@ static int strerror_open(int err, char *buf, size_t size, const char *filename)
 	}
 		break;
 	default:
-		snprintf(buf, size, "%s", strerror_r(err, sbuf, sizeof(sbuf)));
+		snprintf(buf, size, "%s", str_error_r(err, sbuf, sizeof(sbuf)));
 		break;
 	}