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>

1 files changed, 32 insertions, 5 deletions

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