[PATCH] wg: include filename in error messages

[Tony Finch <dot@dotat.at>]

When wg(8) is invoked from a script, it can be hard to tell what
caused an error message if the message does not contain enough
context.

Signed-off-by: Tony Finch <dot@dotat.at>
---
 src/config.c  |  8 ++++----
 src/setconf.c | 11 +++++++----
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git src/config.c src/config.c
index 81ccb47..9f15477 100644
--- src/config.c
+++ src/config.c
@@ -123,7 +123,7 @@ static bool parse_keyfile(uint8_t key[static WG_KEY_LEN], const char *path)

 	f = fopen(path, "r");
 	if (!f) {
-		perror("fopen");
+		fprintf(stderr, "open %s: %s", path, strerror(errno));
 		return false;
 	}

@@ -135,19 +135,19 @@ static bool parse_keyfile(uint8_t key[static WG_KEY_LEN], const char *path)
 			goto out;
 		}

-		fprintf(stderr, "Invalid length key in key file\n");
+		fprintf(stderr, "Invalid length key in %s\n", path);
 		goto out;
 	}
 	dst[WG_KEY_LEN_BASE64 - 1] = '\0';

 	while ((c = getc(f)) != EOF) {
 		if (!char_is_space(c)) {
-			fprintf(stderr, "Found trailing character in key file: `%c'\n", c);
+			fprintf(stderr, "Found trailing character `%c' in %s\n", c, path);
 			goto out;
 		}
 	}
 	if (ferror(f) && errno) {
-		perror("getc");
+		fprintf(stderr, "read %s: %s", path, strerror(errno));
 		goto out;
 	}
 	ret = parse_key(key, dst);
diff --git src/setconf.c src/setconf.c
index 1c5b138..414785d 100644
--- src/setconf.c
+++ src/setconf.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
  */

+#include <errno.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -102,6 +103,7 @@ int setconf_main(int argc, const char *argv[])
 {
 	struct wgdevice *device = NULL;
 	struct config_ctx ctx;
+	const char *path = NULL;
 	FILE *config_input = NULL;
 	char *config_buffer = NULL;
 	size_t config_buffer_len = 0;
@@ -112,9 +114,10 @@ int setconf_main(int argc, const char *argv[])
 		return 1;
 	}

-	config_input = fopen(argv[2], "r");
+	path = argv[2];
+	config_input = fopen(path, "r");
 	if (!config_input) {
-		perror("fopen");
+		fprintf(stderr, "open %s: %s", path, strerror(errno));
 		return 1;
 	}
 	if (!config_read_init(&ctx, !strcmp(argv[0], "addconf"))) {
@@ -123,13 +126,13 @@ int setconf_main(int argc, const char *argv[])
 	}
 	while (getline(&config_buffer, &config_buffer_len, config_input) >= 0) {
 		if (!config_read_line(&ctx, config_buffer)) {
-			fprintf(stderr, "Configuration parsing error\n");
+			fprintf(stderr, "Configuration parsing error in %s\n", path);
 			goto cleanup;
 		}
 	}
 	device = config_read_finish(&ctx);
 	if (!device) {
-		fprintf(stderr, "Invalid configuration\n");
+		fprintf(stderr, "Invalid configuration in %s\n", path);
 		goto cleanup;
 	}
 	strncpy(device->name, argv[1], IFNAMSIZ - 1);
-- 
2.39.2