diff mbox series

[net-next,09/12] tools: bpftool: turn err() and info() macros into functions

Message ID 20171023162416.32753-10-jakub.kicinski@netronome.com
State Accepted, archived
Delegated to: David Miller
Headers show
Series tools: bpftool: Add JSON output to bpftool | expand

Commit Message

Jakub Kicinski Oct. 23, 2017, 4:24 p.m. UTC 
From: Quentin Monnet <quentin.monnet@netronome.com>

Turn err() and info() macros into functions.

In order to avoid naming conflicts with variables in the code, rename
them as p_err() and p_info() respectively.

The behavior of these functions is similar to the one of the macros for
plain output. However, when JSON output is requested, these macros
return a JSON-formatted "error" object instead of printing a message to
stderr.

To handle error messages correctly with JSON, a modification was brought
to their behavior nonetheless: the functions now append a end-of-line
character at the end of the message. This way, we can remove end-of-line
characters at the end of the argument strings, and not have them in the
JSON output.

All error messages are formatted to hold in a single call to p_err(), in
order to produce a single JSON field.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
---
 tools/bpf/bpftool/common.c | 26 +++++++-------
 tools/bpf/bpftool/main.c   | 16 ++++-----
 tools/bpf/bpftool/main.h   | 37 +++++++++++++++++---
 tools/bpf/bpftool/map.c    | 87 +++++++++++++++++++++++++---------------------
 tools/bpf/bpftool/prog.c   | 51 +++++++++++++--------------
 5 files changed, 126 insertions(+), 91 deletions(-)

Comments

Daniel Borkmann Oct. 23, 2017, 8:33 p.m. UTC | #1 
On 10/23/2017 06:24 PM, Jakub Kicinski wrote:
> From: Quentin Monnet <quentin.monnet@netronome.com>
>
> Turn err() and info() macros into functions.
>
> In order to avoid naming conflicts with variables in the code, rename
> them as p_err() and p_info() respectively.
>
> The behavior of these functions is similar to the one of the macros for
> plain output. However, when JSON output is requested, these macros
> return a JSON-formatted "error" object instead of printing a message to
> stderr.
>
> To handle error messages correctly with JSON, a modification was brought
> to their behavior nonetheless: the functions now append a end-of-line
> character at the end of the message. This way, we can remove end-of-line
> characters at the end of the argument strings, and not have them in the
> JSON output.
>
> All error messages are formatted to hold in a single call to p_err(), in
> order to produce a single JSON field.
>
> Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Joe Perches Nov. 3, 2017, 12:59 a.m. UTC | #2 
On Mon, 2017-10-23 at 09:24 -0700, Jakub Kicinski wrote:
> From: Quentin Monnet <quentin.monnet@netronome.com>
> 
> Turn err() and info() macros into functions.
> 
> In order to avoid naming conflicts with variables in the code, rename
> them as p_err() and p_info() respectively.
> 
> The behavior of these functions is similar to the one of the macros for
> plain output. However, when JSON output is requested, these macros
> return a JSON-formatted "error" object instead of printing a message to
> stderr.
> 
> To handle error messages correctly with JSON, a modification was brought
> to their behavior nonetheless: the functions now append a end-of-line
> character at the end of the message. This way, we can remove end-of-line
> characters at the end of the argument strings, and not have them in the
> JSON output.
> 
> All error messages are formatted to hold in a single call to p_err(), in
> order to produce a single JSON field.

> Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
[]
> diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
[]
> @@ -97,4 +93,35 @@ int prog_parse_fd(int *argc, char ***argv);
>  void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes);
>  void print_hex_data_json(uint8_t *data, size_t len);
>  
> +static inline void p_err(const char *fmt, ...)
> +{
> +	va_list ap;
> +
> +	va_start(ap, fmt);
> +	if (json_output) {
> +		jsonw_start_object(json_wtr);
> +		jsonw_name(json_wtr, "error");
> +		jsonw_vprintf_enquote(json_wtr, fmt, ap);
> +		jsonw_end_object(json_wtr);
> +	} else {
> +		fprintf(stderr, "Error: ");
> +		vfprintf(stderr, fmt, ap);
> +		fprintf(stderr, "\n");
> +	}
> +	va_end(ap);
> +}

inline seems very wasteful.

Why not move p_err and p_info to common.c ?

> +
> +static inline void p_info(const char *fmt, ...)
> +{
> +	va_list ap;
> +
> +	if (json_output)
> +		return;
> +
> +	va_start(ap, fmt);
> +	vfprintf(stderr, fmt, ap);
> +	fprintf(stderr, "\n");
> +	va_end(ap);
> +}
>
Quentin Monnet Nov. 3, 2017, 9:26 p.m. UTC | #3 
2017-11-002 17:59 UTC-0700 ~ Joe Perches <joe@perches.com>
> On Mon, 2017-10-23 at 09:24 -0700, Jakub Kicinski wrote:
>> From: Quentin Monnet <quentin.monnet@netronome.com>
>>
>> Turn err() and info() macros into functions.
>>
>> In order to avoid naming conflicts with variables in the code, rename
>> them as p_err() and p_info() respectively.
>>
>> The behavior of these functions is similar to the one of the macros for
>> plain output. However, when JSON output is requested, these macros
>> return a JSON-formatted "error" object instead of printing a message to
>> stderr.
>>
>> To handle error messages correctly with JSON, a modification was brought
>> to their behavior nonetheless: the functions now append a end-of-line
>> character at the end of the message. This way, we can remove end-of-line
>> characters at the end of the argument strings, and not have them in the
>> JSON output.
>>
>> All error messages are formatted to hold in a single call to p_err(), in
>> order to produce a single JSON field.
>> Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
>> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> []
>> diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
> []
>> @@ -97,4 +93,35 @@ int prog_parse_fd(int *argc, char ***argv);
>>  void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes);
>>  void print_hex_data_json(uint8_t *data, size_t len);
>>  
>> +static inline void p_err(const char *fmt, ...)
>> +{
>> +	va_list ap;
>> +
>> +	va_start(ap, fmt);
>> +	if (json_output) {
>> +		jsonw_start_object(json_wtr);
>> +		jsonw_name(json_wtr, "error");
>> +		jsonw_vprintf_enquote(json_wtr, fmt, ap);
>> +		jsonw_end_object(json_wtr);
>> +	} else {
>> +		fprintf(stderr, "Error: ");
>> +		vfprintf(stderr, fmt, ap);
>> +		fprintf(stderr, "\n");
>> +	}
>> +	va_end(ap);
>> +}
> inline seems very wasteful.
>
> Why not move p_err and p_info to common.c ?

Hi Joe,
That's a good point. I wrote a patch to change that, Jakub posted it
some minutes ago. Thanks for your feedback!

Quentin
diff mbox series

Patch

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index e7a756b8ee21..b2533f1cae3e 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -66,8 +66,8 @@  int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type)
 
 	fd = bpf_obj_get(path);
 	if (fd < 0) {
-		err("bpf obj get (%s): %s\n", path,
-		    errno == EACCES && !is_bpffs(dirname(path)) ?
+		p_err("bpf obj get (%s): %s", path,
+		      errno == EACCES && !is_bpffs(dirname(path)) ?
 		    "directory not in bpf file system (bpffs)" :
 		    strerror(errno));
 		return -1;
@@ -79,7 +79,7 @@  int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type)
 		return type;
 	}
 	if (type != exp_type) {
-		err("incorrect object type: %s\n", get_fd_type_name(type));
+		p_err("incorrect object type: %s", get_fd_type_name(type));
 		close(fd);
 		return -1;
 	}
@@ -95,14 +95,14 @@  int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(__u32))
 	int fd;
 
 	if (!is_prefix(*argv, "id")) {
-		err("expected 'id' got %s\n", *argv);
+		p_err("expected 'id' got %s", *argv);
 		return -1;
 	}
 	NEXT_ARG();
 
 	id = strtoul(*argv, &endptr, 0);
 	if (*endptr) {
-		err("can't parse %s as ID\n", *argv);
+		p_err("can't parse %s as ID", *argv);
 		return -1;
 	}
 	NEXT_ARG();
@@ -112,15 +112,15 @@  int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(__u32))
 
 	fd = get_fd_by_id(id);
 	if (fd < 0) {
-		err("can't get prog by id (%u): %s\n", id, strerror(errno));
+		p_err("can't get prog by id (%u): %s", id, strerror(errno));
 		return -1;
 	}
 
 	err = bpf_obj_pin(fd, *argv);
 	close(fd);
 	if (err) {
-		err("can't pin the object (%s): %s\n", *argv,
-		    errno == EACCES && !is_bpffs(dirname(*argv)) ?
+		p_err("can't pin the object (%s): %s", *argv,
+		      errno == EACCES && !is_bpffs(dirname(*argv)) ?
 		    "directory not in bpf file system (bpffs)" :
 		    strerror(errno));
 		return -1;
@@ -153,11 +153,11 @@  int get_fd_type(int fd)
 
 	n = readlink(path, buf, sizeof(buf));
 	if (n < 0) {
-		err("can't read link type: %s\n", strerror(errno));
+		p_err("can't read link type: %s", strerror(errno));
 		return -1;
 	}
 	if (n == sizeof(path)) {
-		err("can't read link type: path too long!\n");
+		p_err("can't read link type: path too long!");
 		return -1;
 	}
 
@@ -181,7 +181,7 @@  char *get_fdinfo(int fd, const char *key)
 
 	fdi = fopen(path, "r");
 	if (!fdi) {
-		err("can't open fdinfo: %s\n", strerror(errno));
+		p_err("can't open fdinfo: %s", strerror(errno));
 		return NULL;
 	}
 
@@ -196,7 +196,7 @@  char *get_fdinfo(int fd, const char *key)
 
 		value = strchr(line, '\t');
 		if (!value || !value[1]) {
-			err("malformed fdinfo!?\n");
+			p_err("malformed fdinfo!?");
 			free(line);
 			return NULL;
 		}
@@ -209,7 +209,7 @@  char *get_fdinfo(int fd, const char *key)
 		return line;
 	}
 
-	err("key '%s' not found in fdinfo\n", key);
+	p_err("key '%s' not found in fdinfo", key);
 	free(line);
 	fclose(fdi);
 	return NULL;
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 71b01bf73912..9989a77fdc4a 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -158,20 +158,20 @@  static int do_batch(int argc, char **argv)
 	int i;
 
 	if (argc < 2) {
-		err("too few parameters for batch\n");
+		p_err("too few parameters for batch");
 		return -1;
 	} else if (!is_prefix(*argv, "file")) {
-		err("expected 'file', got: %s\n", *argv);
+		p_err("expected 'file', got: %s", *argv);
 		return -1;
 	} else if (argc > 2) {
-		err("too many parameters for batch\n");
+		p_err("too many parameters for batch");
 		return -1;
 	}
 	NEXT_ARG();
 
 	fp = fopen(*argv, "r");
 	if (!fp) {
-		err("Can't open file (%s): %s\n", *argv, strerror(errno));
+		p_err("Can't open file (%s): %s", *argv, strerror(errno));
 		return -1;
 	}
 
@@ -189,8 +189,8 @@  static int do_batch(int argc, char **argv)
 		while (n_argv[n_argc]) {
 			n_argc++;
 			if (n_argc == ARRAY_SIZE(n_argv)) {
-				err("line %d has too many arguments, skip\n",
-				    lines);
+				p_err("line %d has too many arguments, skip",
+				      lines);
 				n_argc = 0;
 				break;
 			}
@@ -225,7 +225,7 @@  static int do_batch(int argc, char **argv)
 		perror("reading batch file failed");
 		err = -1;
 	} else {
-		info("processed %d lines\n", lines);
+		p_info("processed %d lines", lines);
 		err = 0;
 	}
 err_close:
@@ -279,7 +279,7 @@  int main(int argc, char **argv)
 	if (json_output) {
 		json_wtr = jsonw_new(stdout);
 		if (!json_wtr) {
-			err("failed to create JSON writer\n");
+			p_err("failed to create JSON writer");
 			return -1;
 		}
 		jsonw_pretty(json_wtr, pretty_output);
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 693fc9710be1..04c88b55d8c7 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -45,15 +45,11 @@ 
 
 #include "json_writer.h"
 
-#define err(msg...)	fprintf(stderr, "Error: " msg)
-#define warn(msg...)	fprintf(stderr, "Warning: " msg)
-#define info(msg...)	fprintf(stderr, msg)
-
 #define ptr_to_u64(ptr)	((__u64)(unsigned long)(ptr))
 
 #define NEXT_ARG()	({ argc--; argv++; if (argc < 0) usage(); })
 #define NEXT_ARGP()	({ (*argc)--; (*argv)++; if (*argc < 0) usage(); })
-#define BAD_ARG()	({ err("what is '%s'?\n", *argv); -1; })
+#define BAD_ARG()	({ p_err("what is '%s'?\n", *argv); -1; })
 
 #define BPF_TAG_FMT	"%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
 
@@ -97,4 +93,35 @@  int prog_parse_fd(int *argc, char ***argv);
 void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes);
 void print_hex_data_json(uint8_t *data, size_t len);
 
+static inline void p_err(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	if (json_output) {
+		jsonw_start_object(json_wtr);
+		jsonw_name(json_wtr, "error");
+		jsonw_vprintf_enquote(json_wtr, fmt, ap);
+		jsonw_end_object(json_wtr);
+	} else {
+		fprintf(stderr, "Error: ");
+		vfprintf(stderr, fmt, ap);
+		fprintf(stderr, "\n");
+	}
+	va_end(ap);
+}
+
+static inline void p_info(const char *fmt, ...)
+{
+	va_list ap;
+
+	if (json_output)
+		return;
+
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, "\n");
+	va_end(ap);
+}
+
 #endif
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 14d89bfabc66..86c128c433ba 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -81,19 +81,19 @@  static unsigned int get_possible_cpus(void)
 
 	fd = open("/sys/devices/system/cpu/possible", O_RDONLY);
 	if (fd < 0) {
-		err("can't open sysfs possible cpus\n");
+		p_err("can't open sysfs possible cpus");
 		exit(-1);
 	}
 
 	n = read(fd, buf, sizeof(buf));
 	if (n < 2) {
-		err("can't read sysfs possible cpus\n");
+		p_err("can't read sysfs possible cpus");
 		exit(-1);
 	}
 	close(fd);
 
 	if (n == sizeof(buf)) {
-		err("read sysfs possible cpus overflow\n");
+		p_err("read sysfs possible cpus overflow");
 		exit(-1);
 	}
 
@@ -161,14 +161,14 @@  static int map_parse_fd(int *argc, char ***argv)
 
 		id = strtoul(**argv, &endptr, 0);
 		if (*endptr) {
-			err("can't parse %s as ID\n", **argv);
+			p_err("can't parse %s as ID", **argv);
 			return -1;
 		}
 		NEXT_ARGP();
 
 		fd = bpf_map_get_fd_by_id(id);
 		if (fd < 0)
-			err("get map by id (%u): %s\n", id, strerror(errno));
+			p_err("get map by id (%u): %s", id, strerror(errno));
 		return fd;
 	} else if (is_prefix(**argv, "pinned")) {
 		char *path;
@@ -181,7 +181,7 @@  static int map_parse_fd(int *argc, char ***argv)
 		return open_obj_pinned_any(path, BPF_OBJ_MAP);
 	}
 
-	err("expected 'id' or 'pinned', got: '%s'?\n", **argv);
+	p_err("expected 'id' or 'pinned', got: '%s'?", **argv);
 	return -1;
 }
 
@@ -197,7 +197,7 @@  map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len)
 
 	err = bpf_obj_get_info_by_fd(fd, info, info_len);
 	if (err) {
-		err("can't get map info: %s\n", strerror(errno));
+		p_err("can't get map info: %s", strerror(errno));
 		close(fd);
 		return err;
 	}
@@ -288,14 +288,14 @@  static char **parse_bytes(char **argv, const char *name, unsigned char *val,
 	while (i < n && argv[i]) {
 		val[i] = strtoul(argv[i], &endptr, 0);
 		if (*endptr) {
-			err("error parsing byte: %s\n", argv[i]);
+			p_err("error parsing byte: %s", argv[i]);
 			return NULL;
 		}
 		i++;
 	}
 
 	if (i != n) {
-		err("%s expected %d bytes got %d\n", name, n, i);
+		p_err("%s expected %d bytes got %d", name, n, i);
 		return NULL;
 	}
 
@@ -309,16 +309,16 @@  static int parse_elem(char **argv, struct bpf_map_info *info,
 	if (!*argv) {
 		if (!key && !value)
 			return 0;
-		err("did not find %s\n", key ? "key" : "value");
+		p_err("did not find %s", key ? "key" : "value");
 		return -1;
 	}
 
 	if (is_prefix(*argv, "key")) {
 		if (!key) {
 			if (key_size)
-				err("duplicate key\n");
+				p_err("duplicate key");
 			else
-				err("unnecessary key\n");
+				p_err("unnecessary key");
 			return -1;
 		}
 
@@ -333,9 +333,9 @@  static int parse_elem(char **argv, struct bpf_map_info *info,
 
 		if (!value) {
 			if (value_size)
-				err("duplicate value\n");
+				p_err("duplicate value");
 			else
-				err("unnecessary value\n");
+				p_err("unnecessary value");
 			return -1;
 		}
 
@@ -345,11 +345,11 @@  static int parse_elem(char **argv, struct bpf_map_info *info,
 			int argc = 2;
 
 			if (value_size != 4) {
-				err("value smaller than 4B for map in map?\n");
+				p_err("value smaller than 4B for map in map?");
 				return -1;
 			}
 			if (!argv[0] || !argv[1]) {
-				err("not enough value arguments for map in map\n");
+				p_err("not enough value arguments for map in map");
 				return -1;
 			}
 
@@ -363,11 +363,11 @@  static int parse_elem(char **argv, struct bpf_map_info *info,
 			int argc = 2;
 
 			if (value_size != 4) {
-				err("value smaller than 4B for map of progs?\n");
+				p_err("value smaller than 4B for map of progs?");
 				return -1;
 			}
 			if (!argv[0] || !argv[1]) {
-				err("not enough value arguments for map of progs\n");
+				p_err("not enough value arguments for map of progs");
 				return -1;
 			}
 
@@ -388,7 +388,7 @@  static int parse_elem(char **argv, struct bpf_map_info *info,
 	} else if (is_prefix(*argv, "any") || is_prefix(*argv, "noexist") ||
 		   is_prefix(*argv, "exist")) {
 		if (!flags) {
-			err("flags specified multiple times: %s\n", *argv);
+			p_err("flags specified multiple times: %s", *argv);
 			return -1;
 		}
 
@@ -403,7 +403,7 @@  static int parse_elem(char **argv, struct bpf_map_info *info,
 				  value_size, NULL, value_fd);
 	}
 
-	err("expected key or value, got: %s\n", *argv);
+	p_err("expected key or value, got: %s", *argv);
 	return -1;
 }
 
@@ -499,22 +499,21 @@  static int do_show(int argc, char **argv)
 		if (err) {
 			if (errno == ENOENT)
 				break;
-			err("can't get next map: %s\n", strerror(errno));
-			if (errno == EINVAL)
-				err("kernel too old?\n");
+			p_err("can't get next map: %s%s", strerror(errno),
+			      errno == EINVAL ? " -- kernel too old?" : "");
 			return -1;
 		}
 
 		fd = bpf_map_get_fd_by_id(id);
 		if (fd < 0) {
-			err("can't get map by id (%u): %s\n",
-			    id, strerror(errno));
+			p_err("can't get map by id (%u): %s",
+			      id, strerror(errno));
 			return -1;
 		}
 
 		err = bpf_obj_get_info_by_fd(fd, &info, &len);
 		if (err) {
-			err("can't get map info: %s\n", strerror(errno));
+			p_err("can't get map info: %s", strerror(errno));
 			close(fd);
 			return -1;
 		}
@@ -547,7 +546,7 @@  static int do_dump(int argc, char **argv)
 		return -1;
 
 	if (map_is_map_of_maps(info.type) || map_is_map_of_progs(info.type)) {
-		err("Dumping maps of maps and program maps not supported\n");
+		p_err("Dumping maps of maps and program maps not supported");
 		close(fd);
 		return -1;
 	}
@@ -555,7 +554,7 @@  static int do_dump(int argc, char **argv)
 	key = malloc(info.key_size);
 	value = alloc_value(&info);
 	if (!key || !value) {
-		err("mem alloc failed\n");
+		p_err("mem alloc failed");
 		err = -1;
 		goto exit_free;
 	}
@@ -577,9 +576,19 @@  static int do_dump(int argc, char **argv)
 			else
 				print_entry_plain(&info, key, value);
 		} else {
-			info("can't lookup element with key: ");
-			fprint_hex(stderr, key, info.key_size, " ");
-			fprintf(stderr, "\n");
+			if (json_output) {
+				jsonw_name(json_wtr, "key");
+				print_hex_data_json(key, info.key_size);
+				jsonw_name(json_wtr, "value");
+				jsonw_start_object(json_wtr);
+				jsonw_string_field(json_wtr, "error",
+						   "can't lookup element");
+				jsonw_end_object(json_wtr);
+			} else {
+				p_info("can't lookup element with key: ");
+				fprint_hex(stderr, key, info.key_size, " ");
+				fprintf(stderr, "\n");
+			}
 		}
 
 		prev_key = key;
@@ -619,7 +628,7 @@  static int do_update(int argc, char **argv)
 	key = malloc(info.key_size);
 	value = alloc_value(&info);
 	if (!key || !value) {
-		err("mem alloc failed");
+		p_err("mem alloc failed");
 		err = -1;
 		goto exit_free;
 	}
@@ -631,7 +640,7 @@  static int do_update(int argc, char **argv)
 
 	err = bpf_map_update_elem(fd, key, value, flags);
 	if (err) {
-		err("update failed: %s\n", strerror(errno));
+		p_err("update failed: %s", strerror(errno));
 		goto exit_free;
 	}
 
@@ -663,7 +672,7 @@  static int do_lookup(int argc, char **argv)
 	key = malloc(info.key_size);
 	value = alloc_value(&info);
 	if (!key || !value) {
-		err("mem alloc failed");
+		p_err("mem alloc failed");
 		err = -1;
 		goto exit_free;
 	}
@@ -687,7 +696,7 @@  static int do_lookup(int argc, char **argv)
 			printf("\n\nNot found\n");
 		}
 	} else {
-		err("lookup failed: %s\n", strerror(errno));
+		p_err("lookup failed: %s", strerror(errno));
 	}
 
 exit_free:
@@ -716,7 +725,7 @@  static int do_getnext(int argc, char **argv)
 	key = malloc(info.key_size);
 	nextkey = malloc(info.key_size);
 	if (!key || !nextkey) {
-		err("mem alloc failed");
+		p_err("mem alloc failed");
 		err = -1;
 		goto exit_free;
 	}
@@ -733,7 +742,7 @@  static int do_getnext(int argc, char **argv)
 
 	err = bpf_map_get_next_key(fd, key, nextkey);
 	if (err) {
-		err("can't get next key: %s\n", strerror(errno));
+		p_err("can't get next key: %s", strerror(errno));
 		goto exit_free;
 	}
 
@@ -786,7 +795,7 @@  static int do_delete(int argc, char **argv)
 
 	key = malloc(info.key_size);
 	if (!key) {
-		err("mem alloc failed");
+		p_err("mem alloc failed");
 		err = -1;
 		goto exit_free;
 	}
@@ -797,7 +806,7 @@  static int do_delete(int argc, char **argv)
 
 	err = bpf_map_delete_elem(fd, key);
 	if (err)
-		err("delete failed: %s\n", strerror(errno));
+		p_err("delete failed: %s", strerror(errno));
 
 exit_free:
 	free(key);
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 43e49799a624..41bd5390b4fc 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -104,21 +104,21 @@  static int prog_fd_by_tag(unsigned char *tag)
 	while (true) {
 		err = bpf_prog_get_next_id(id, &id);
 		if (err) {
-			err("%s\n", strerror(errno));
+			p_err("%s", strerror(errno));
 			return -1;
 		}
 
 		fd = bpf_prog_get_fd_by_id(id);
 		if (fd < 0) {
-			err("can't get prog by id (%u): %s\n",
-			    id, strerror(errno));
+			p_err("can't get prog by id (%u): %s",
+			      id, strerror(errno));
 			return -1;
 		}
 
 		err = bpf_obj_get_info_by_fd(fd, &info, &len);
 		if (err) {
-			err("can't get prog info (%u): %s\n",
-			    id, strerror(errno));
+			p_err("can't get prog info (%u): %s",
+			      id, strerror(errno));
 			close(fd);
 			return -1;
 		}
@@ -142,14 +142,14 @@  int prog_parse_fd(int *argc, char ***argv)
 
 		id = strtoul(**argv, &endptr, 0);
 		if (*endptr) {
-			err("can't parse %s as ID\n", **argv);
+			p_err("can't parse %s as ID", **argv);
 			return -1;
 		}
 		NEXT_ARGP();
 
 		fd = bpf_prog_get_fd_by_id(id);
 		if (fd < 0)
-			err("get by id (%u): %s\n", id, strerror(errno));
+			p_err("get by id (%u): %s", id, strerror(errno));
 		return fd;
 	} else if (is_prefix(**argv, "tag")) {
 		unsigned char tag[BPF_TAG_SIZE];
@@ -159,7 +159,7 @@  int prog_parse_fd(int *argc, char ***argv)
 		if (sscanf(**argv, BPF_TAG_FMT, tag, tag + 1, tag + 2,
 			   tag + 3, tag + 4, tag + 5, tag + 6, tag + 7)
 		    != BPF_TAG_SIZE) {
-			err("can't parse tag\n");
+			p_err("can't parse tag");
 			return -1;
 		}
 		NEXT_ARGP();
@@ -176,7 +176,7 @@  int prog_parse_fd(int *argc, char ***argv)
 		return open_obj_pinned_any(path, BPF_OBJ_PROG);
 	}
 
-	err("expected 'id', 'tag' or 'pinned', got: '%s'?\n", **argv);
+	p_err("expected 'id', 'tag' or 'pinned', got: '%s'?", **argv);
 	return -1;
 }
 
@@ -311,7 +311,7 @@  static int show_prog(int fd)
 
 	err = bpf_obj_get_info_by_fd(fd, &info, &len);
 	if (err) {
-		err("can't get prog info: %s\n", strerror(errno));
+		p_err("can't get prog info: %s", strerror(errno));
 		return -1;
 	}
 
@@ -349,17 +349,16 @@  static int do_show(int argc, char **argv)
 				err = 0;
 				break;
 			}
-			err("can't get next program: %s\n", strerror(errno));
-			if (errno == EINVAL)
-				err("kernel too old?\n");
+			p_err("can't get next program: %s%s", strerror(errno),
+			      errno == EINVAL ? " -- kernel too old?" : "");
 			err = -1;
 			break;
 		}
 
 		fd = bpf_prog_get_fd_by_id(id);
 		if (fd < 0) {
-			err("can't get prog by id (%u): %s\n",
-			    id, strerror(errno));
+			p_err("can't get prog by id (%u): %s",
+			      id, strerror(errno));
 			err = -1;
 			break;
 		}
@@ -498,7 +497,7 @@  static int do_dump(int argc, char **argv)
 		member_len = &info.xlated_prog_len;
 		member_ptr = &info.xlated_prog_insns;
 	} else {
-		err("expected 'xlated' or 'jited', got: %s\n", *argv);
+		p_err("expected 'xlated' or 'jited', got: %s", *argv);
 		return -1;
 	}
 	NEXT_ARG();
@@ -513,7 +512,7 @@  static int do_dump(int argc, char **argv)
 	if (is_prefix(*argv, "file")) {
 		NEXT_ARG();
 		if (!argc) {
-			err("expected file path\n");
+			p_err("expected file path");
 			return -1;
 		}
 
@@ -531,12 +530,12 @@  static int do_dump(int argc, char **argv)
 
 	err = bpf_obj_get_info_by_fd(fd, &info, &len);
 	if (err) {
-		err("can't get prog info: %s\n", strerror(errno));
+		p_err("can't get prog info: %s", strerror(errno));
 		return -1;
 	}
 
 	if (!*member_len) {
-		info("no instructions returned\n");
+		p_info("no instructions returned");
 		close(fd);
 		return 0;
 	}
@@ -545,7 +544,7 @@  static int do_dump(int argc, char **argv)
 
 	buf = malloc(buf_size);
 	if (!buf) {
-		err("mem alloc failed\n");
+		p_err("mem alloc failed");
 		close(fd);
 		return -1;
 	}
@@ -558,28 +557,28 @@  static int do_dump(int argc, char **argv)
 	err = bpf_obj_get_info_by_fd(fd, &info, &len);
 	close(fd);
 	if (err) {
-		err("can't get prog info: %s\n", strerror(errno));
+		p_err("can't get prog info: %s", strerror(errno));
 		goto err_free;
 	}
 
 	if (*member_len > buf_size) {
-		err("too many instructions returned\n");
+		p_err("too many instructions returned");
 		goto err_free;
 	}
 
 	if (filepath) {
 		fd = open(filepath, O_WRONLY | O_CREAT | O_TRUNC, 0600);
 		if (fd < 0) {
-			err("can't open file %s: %s\n", filepath,
-			    strerror(errno));
+			p_err("can't open file %s: %s", filepath,
+			      strerror(errno));
 			goto err_free;
 		}
 
 		n = write(fd, buf, *member_len);
 		close(fd);
 		if (n != *member_len) {
-			err("error writing output file: %s\n",
-			    n < 0 ? strerror(errno) : "short write");
+			p_err("error writing output file: %s",
+			      n < 0 ? strerror(errno) : "short write");
 			goto err_free;
 		}
 	} else {