tools: bpftool: turn err() and info() macros into functions

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

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;

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);

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