diff mbox series

[bpf-next,2/2] tools/bpf: simplify libbpf API function libbpf_set_print()

Message ID 20190201082444.2770286-1-yhs@fb.com
State Superseded
Delegated to: BPF Maintainers
Headers show
Series tools/bpf: changes of libbpf debug interfaces | expand

Commit Message

Yonghong Song Feb. 1, 2019, 8:24 a.m. UTC 
Currently, the libbpf API function libbpf_set_print()
takes three function pointer parameters for warning, info
and debug printout respectively.

This patch changes the API to have just one function pointer
parameter and the function pointer has one additional
parameter "debugging level". So if in the future, if
the debug level is increased, the function signature
won't change.

The libbpf internal function libbpf_dprint_level_available()
previous is able to return whether a particular debug level
(warning, info or debug) is available or not.
With this change, there is only one function for debug
printout, so no easy way to test whether a particular
level is supported or not. This function is only used
for btf.c to allocate for log buffers. Such a compromise
should be acceptable. The function is changed to
libbpf_dprint_available().

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 tools/lib/bpf/btf.c                           |  2 +-
 tools/lib/bpf/libbpf.c                        | 37 +++++--------------
 tools/lib/bpf/libbpf.h                        | 14 ++-----
 tools/lib/bpf/test_libbpf.cpp                 |  2 +-
 tools/lib/bpf/util.h                          |  2 +-
 tools/perf/util/bpf-loader.c                  | 32 ++++++----------
 tools/testing/selftests/bpf/test_btf.c        |  7 ++--
 .../testing/selftests/bpf/test_libbpf_open.c  | 36 +++++++++---------
 tools/testing/selftests/bpf/test_progs.c      | 20 +++++++++-
 9 files changed, 67 insertions(+), 85 deletions(-)
diff mbox series

Patch

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 159104ec31dc..4bbf7f363c50 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -377,7 +377,7 @@  struct btf *btf__new(__u8 *data, __u32 size)
 
 	btf->fd = -1;
 
-	if (libbpf_dprint_level_available(LIBBPF_DEBUG)) {
+	if (libbpf_dprint_available()) {
 		log_buf = malloc(BPF_LOG_BUF_SIZE);
 		if (!log_buf) {
 			err = -ENOMEM;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 1c7e25ebbe85..38a2e71ea369 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -54,8 +54,8 @@ 
 
 #define __printf(a, b)	__attribute__((format(printf, a, b)))
 
-__printf(1, 2)
-static int __base_pr(const char *format, ...)
+__printf(2, 3)
+static int __base_pr(enum libbpf_print_level level, const char *format, ...)
 {
 	va_list args;
 	int err;
@@ -66,17 +66,11 @@  static int __base_pr(const char *format, ...)
 	return err;
 }
 
-static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
-static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
-static __printf(1, 2) libbpf_print_fn_t __pr_debug;
+static __printf(2, 3) libbpf_print_fn_t __libbpf_pr = __base_pr;
 
-void libbpf_set_print(libbpf_print_fn_t warn,
-		      libbpf_print_fn_t info,
-		      libbpf_print_fn_t debug)
+void libbpf_set_print(libbpf_print_fn_t fn)
 {
-	__pr_warning = warn;
-	__pr_info = info;
-	__pr_debug = debug;
+	__libbpf_pr = fn;
 }
 
 __printf(2, 3)
@@ -85,27 +79,14 @@  void libbpf_dprint(enum libbpf_print_level level, const char *format, ...)
 	va_list args;
 
 	va_start(args, format);
-	if (level == LIBBPF_WARN) {
-		if (__pr_warning)
-			__pr_warning(format, args);
-	} else if (level == LIBBPF_INFO) {
-		if (__pr_info)
-			__pr_info(format, args);
-	} else {
-		if (__pr_debug)
-			__pr_debug(format, args);
-	}
+	if (__libbpf_pr)
+		__libbpf_pr(level, format, args);
 	va_end(args);
 }
 
-bool libbpf_dprint_level_available(enum libbpf_print_level level)
+bool libbpf_dprint_available(void)
 {
-	if (level == LIBBPF_WARN)
-		return !!__pr_warning;
-	else if (level == LIBBPF_INFO)
-		return !!__pr_info;
-	else
-		return !!__pr_debug;
+	return !!__libbpf_pr;
 }
 
 #define STRERR_BUFSIZE  128
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 4e21971101c9..f8f27f1bb6bf 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -53,17 +53,11 @@  enum libbpf_print_level {
         LIBBPF_DEBUG,
 };
 
-/*
- * __printf is defined in include/linux/compiler-gcc.h. However,
- * it would be better if libbpf.h didn't depend on Linux header files.
- * So instead of __printf, here we use gcc attribute directly.
- */
-typedef int (*libbpf_print_fn_t)(const char *, ...)
-	__attribute__((format(printf, 1, 2)));
+typedef int (*libbpf_print_fn_t)(enum libbpf_print_level level,
+				 const char *, ...)
+	__attribute__((format(printf, 2, 3)));
 
-LIBBPF_API void libbpf_set_print(libbpf_print_fn_t warn,
-				 libbpf_print_fn_t info,
-				 libbpf_print_fn_t debug);
+LIBBPF_API void libbpf_set_print(libbpf_print_fn_t fn);
 
 /* Hide internal to user */
 struct bpf_object;
diff --git a/tools/lib/bpf/test_libbpf.cpp b/tools/lib/bpf/test_libbpf.cpp
index be67f5ea2c19..fc134873bb6d 100644
--- a/tools/lib/bpf/test_libbpf.cpp
+++ b/tools/lib/bpf/test_libbpf.cpp
@@ -8,7 +8,7 @@ 
 int main(int argc, char *argv[])
 {
     /* libbpf.h */
-    libbpf_set_print(NULL, NULL, NULL);
+    libbpf_set_print(NULL);
 
     /* bpf.h */
     bpf_prog_get_fd_by_id(0);
diff --git a/tools/lib/bpf/util.h b/tools/lib/bpf/util.h
index b07657600f7c..6b93ebf61ea6 100644
--- a/tools/lib/bpf/util.h
+++ b/tools/lib/bpf/util.h
@@ -14,7 +14,7 @@  extern void libbpf_dprint(enum libbpf_print_level level,
 			  const char *format, ...)
 	__attribute__((format(printf, 2, 3)));
 
-extern bool libbpf_dprint_level_available(enum libbpf_print_level level);
+extern bool libbpf_dprint_available(void);
 
 #define __pr(level, fmt, ...)	\
 do {				\
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 2f3eb6d293ee..c492f3a2acdc 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -24,21 +24,17 @@ 
 #include "llvm-utils.h"
 #include "c++/clang-c.h"
 
-#define DEFINE_PRINT_FN(name, level) \
-static int libbpf_##name(const char *fmt, ...)	\
-{						\
-	va_list args;				\
-	int ret;				\
-						\
-	va_start(args, fmt);			\
-	ret = veprintf(level, verbose, pr_fmt(fmt), args);\
-	va_end(args);				\
-	return ret;				\
-}
+static int libbpf_perf_dprint(enum libbpf_print_level level __attribute__((unused)),
+			      const char *fmt, ...)
+{
+	va_list args;
+	int ret;
 
-DEFINE_PRINT_FN(warning, 1)
-DEFINE_PRINT_FN(info, 1)
-DEFINE_PRINT_FN(debug, 1)
+	va_start(args, fmt);
+	ret = veprintf(1, verbose, pr_fmt(fmt), args);
+	va_end(args);
+	return ret;
+}
 
 struct bpf_prog_priv {
 	bool is_tp;
@@ -59,9 +55,7 @@  bpf__prepare_load_buffer(void *obj_buf, size_t obj_buf_sz, const char *name)
 	struct bpf_object *obj;
 
 	if (!libbpf_initialized) {
-		libbpf_set_print(libbpf_warning,
-				 libbpf_info,
-				 libbpf_debug);
+		libbpf_set_print(libbpf_perf_dprint);
 		libbpf_initialized = true;
 	}
 
@@ -79,9 +73,7 @@  struct bpf_object *bpf__prepare_load(const char *filename, bool source)
 	struct bpf_object *obj;
 
 	if (!libbpf_initialized) {
-		libbpf_set_print(libbpf_warning,
-				 libbpf_info,
-				 libbpf_debug);
+		libbpf_set_print(libbpf_perf_dprint);
 		libbpf_initialized = true;
 	}
 
diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c
index 179f1d8ec5bf..aebaeff5a5a0 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -54,8 +54,9 @@  static int count_result(int err)
 
 #define __printf(a, b)	__attribute__((format(printf, a, b)))
 
-__printf(1, 2)
-static int __base_pr(const char *format, ...)
+__printf(2, 3)
+static int __base_pr(enum libbpf_print_level level __attribute__((unused)),
+		     const char *format, ...)
 {
 	va_list args;
 	int err;
@@ -5650,7 +5651,7 @@  int main(int argc, char **argv)
 		return err;
 
 	if (args.always_log)
-		libbpf_set_print(__base_pr, __base_pr, __base_pr);
+		libbpf_set_print(__base_pr);
 
 	if (args.raw_test)
 		err |= test_raw();
diff --git a/tools/testing/selftests/bpf/test_libbpf_open.c b/tools/testing/selftests/bpf/test_libbpf_open.c
index 8fcd1c076add..b9ff3bf76544 100644
--- a/tools/testing/selftests/bpf/test_libbpf_open.c
+++ b/tools/testing/selftests/bpf/test_libbpf_open.c
@@ -34,23 +34,22 @@  static void usage(char *argv[])
 	printf("\n");
 }
 
-#define DEFINE_PRINT_FN(name, enabled) \
-static int libbpf_##name(const char *fmt, ...)  	\
-{							\
-        va_list args;					\
-        int ret;					\
-							\
-        va_start(args, fmt);				\
-	if (enabled) {					\
-		fprintf(stderr, "[" #name "] ");	\
-		ret = vfprintf(stderr, fmt, args);	\
-	}						\
-        va_end(args);					\
-        return ret;					\
+static bool debug = 0;
+static int libbpf_debug_print(enum libbpf_print_level level,
+			      const char *fmt, ...)
+{
+	va_list args;
+	int ret;
+
+	if (level == LIBBPF_DEBUG && !debug)
+		return 0;
+
+	va_start(args, fmt);
+	fprintf(stderr, "[%d] ", level);
+	ret = vfprintf(stderr, fmt, args);
+	va_end(args);
+	return ret;
 }
-DEFINE_PRINT_FN(warning, 1)
-DEFINE_PRINT_FN(info, 1)
-DEFINE_PRINT_FN(debug, 1)
 
 #define EXIT_FAIL_LIBBPF EXIT_FAILURE
 #define EXIT_FAIL_OPTION 2
@@ -120,15 +119,14 @@  int main(int argc, char **argv)
 	int longindex = 0;
 	int opt;
 
-	libbpf_set_print(libbpf_warning, libbpf_info, NULL);
+	libbpf_set_print(libbpf_debug_print);
 
 	/* Parse commands line args */
 	while ((opt = getopt_long(argc, argv, "hDq",
 				  long_options, &longindex)) != -1) {
 		switch (opt) {
 		case 'D':
-			libbpf_set_print(libbpf_warning, libbpf_info,
-					 libbpf_debug);
+			debug = 1;
 			break;
 		case 'q': /* Use in scripting mode */
 			verbose = 0;
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index d8940b8b2f8d..294beff3374e 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -10,6 +10,7 @@ 
 #include <string.h>
 #include <assert.h>
 #include <stdlib.h>
+#include <stdarg.h>
 #include <time.h>
 
 #include <linux/types.h>
@@ -1783,6 +1784,21 @@  static void test_task_fd_query_tp(void)
 				   "sys_enter_read");
 }
 
+static int libbpf_debug_print(enum libbpf_print_level level,
+			      const char *format, ...)
+{
+	va_list args;
+	int ret;
+
+	if (level == LIBBPF_DEBUG)
+		return 0;
+
+	va_start(args, format);
+	ret = vfprintf(stderr, format, args);
+	va_end(args);
+	return ret;
+}
+
 static void test_reference_tracking()
 {
 	const char *file = "./test_sk_lookup_kern.o";
@@ -1809,9 +1825,9 @@  static void test_reference_tracking()
 
 		/* Expect verifier failure if test name has 'fail' */
 		if (strstr(title, "fail") != NULL) {
-			libbpf_set_print(NULL, NULL, NULL);
+			libbpf_set_print(NULL);
 			err = !bpf_program__load(prog, "GPL", 0);
-			libbpf_set_print(printf, printf, NULL);
+			libbpf_set_print(libbpf_debug_print);
 		} else {
 			err = bpf_program__load(prog, "GPL", 0);
 		}