Logging: Use ringlogger for logging from the extension

Signed-off-by: Roopesh Chander <roop@roopc.net>

WireGuard/Shared/Logging/Logger.swift

@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import os.log
+
+class Logger {
+    static var logPtr: UnsafeMutablePointer<log>?
+
+    static func configure(withFilePath filePath: String) -> Bool {
+        let logPtr = filePath.withCString { filePathCStr -> UnsafeMutablePointer<log>? in
+            return open_log(filePathCStr)
+        }
+        Logger.logPtr = logPtr
+        return (logPtr != nil)
+    }
+
+    static func writeLog(mergedWith otherLogFile: String, to targetFile: String) -> Bool {
+        let otherlogPtr = otherLogFile.withCString { otherLogFileCStr -> UnsafeMutablePointer<log>? in
+            return open_log(otherLogFileCStr)
+        }
+        if let thisLogPtr = Logger.logPtr, let otherlogPtr = otherlogPtr {
+            return targetFile.withCString { targetFileCStr -> Bool in
+                let returnValue = write_logs_to_file(targetFileCStr, thisLogPtr, otherlogPtr)
+                return (returnValue == 0)
+            }
+        }
+        return false
+    }
+}
+
+func wg_log(_ type: OSLogType, staticMessage msg: StaticString) {
+    // Write to os log
+    os_log(msg, log: OSLog.default, type: type)
+    // Write to file log
+    let msgString: String = msg.withUTF8Buffer { (ptr: UnsafeBufferPointer<UInt8>) -> String in
+        return String(decoding: ptr, as: UTF8.self)
+    }
+    file_log(type: type, message: msgString)
+}
+
+func wg_log(_ type: OSLogType, message msg: String) {
+    // Write to os log
+    os_log("%{public}s", log: OSLog.default, type: type, msg)
+    // Write to file log
+    file_log(type: type, message: msg)
+}
+
+private func file_log(type: OSLogType, message: String) {
+    message.withCString { messageCStr in
+        if let logPtr = Logger.logPtr {
+            write_msg_to_log(logPtr, messageCStr)
+        }
+    }
+}

WireGuard/Shared/Logging/ringlogger.c

@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2018 WireGuard LLC. All Rights Reserved.
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/mman.h>
+#include "ringlogger.h"
+
+void write_msg_to_log(struct log *log, const char *msg)
+{
+	struct log_line *line = &log->lines[(log->header.first + log->header.len) % MAX_LINES];
+
+	if (log->header.len == MAX_LINES)
+		log->header.first = (log->header.first + 1) % MAX_LINES;
+	else
+		++log->header.len;
+
+	gettimeofday(&line->tv, NULL);
+	strncpy(line->line, msg, MAX_LOG_LINE_LENGTH - 1);
+	line->line[MAX_LOG_LINE_LENGTH - 1] = '\0';
+
+	msync(&log->header, sizeof(log->header), MS_ASYNC);
+	msync(line, sizeof(*line), MS_ASYNC);
+}
+
+static bool first_before_second(const struct log_line *line1, const struct log_line *line2)
+{
+	if (line1->tv.tv_sec <= line2->tv.tv_sec)
+		return true;
+	else if (line1->tv.tv_sec == line2->tv.tv_sec)
+		return line1->tv.tv_usec <= line2->tv.tv_usec;
+	return false;
+}
+
+int write_logs_to_file(const char *file_name, const struct log *log1, const struct log *log2)
+{
+	uint32_t i1, i2, len1 = log1->header.len, len2 = log2->header.len;
+	char buf[MAX_LOG_LINE_LENGTH];
+	FILE *file;
+
+	if (len1 > MAX_LINES)
+		len1 = MAX_LINES;
+	if (len2 > MAX_LINES)
+		len2 = MAX_LINES;
+
+	file = fopen(file_name, "w");
+	if (!file)
+		return -errno;
+
+	for (i1 = 0, i2 = 0;;) {
+		const struct log_line *line1 = &log1->lines[(log1->header.first + i1) % MAX_LINES];
+		const struct log_line *line2 = &log2->lines[(log2->header.first + i2) % MAX_LINES];
+		const struct log_line *line;
+
+		if (i1 < len1 && (i2 >= len2 || first_before_second(line1, line2))) {
+			line = line1;
+			++i1;
+		} else if (i2 < len2 && (i1 >= len1 || first_before_second(line2, line1))) {
+			line = line2;
+			++i2;
+		} else {
+			break;
+		}
+		memcpy(buf, line->line, MAX_LOG_LINE_LENGTH);
+		buf[MAX_LOG_LINE_LENGTH - 1] = '\0';
+		if (fprintf(file, "%lu.%06d: %s\n", line->tv.tv_sec, line->tv.tv_usec, buf) < 0) {
+			int ret = -errno;
+			fclose(file);
+			return ret;
+		}
+	}
+	fclose(file);
+	return 0;
+}
+
+struct log *open_log(const char *file_name)
+{
+	int fd;
+	struct log *log;
+
+	fd = open(file_name, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
+	if (fd < 0)
+		return NULL;
+	if (ftruncate(fd, sizeof(*log)))
+		return NULL;
+	log = mmap(NULL, sizeof(*log), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if (log == MAP_FAILED)
+		return NULL;
+	close(fd);
+
+	if (log->magic != MAGIC) {
+		memset(log, 0, sizeof(*log));
+		log->magic = MAGIC;
+		msync(log, sizeof(*log), MS_ASYNC);
+	}
+
+	return log;
+}

WireGuard/Shared/Logging/ringlogger.h

@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2018 WireGuard LLC. All Rights Reserved.
+ */
+
+#ifndef RINGLOGGER_H
+#define RINGLOGGER_H
+
+enum {
+    MAX_LOG_LINE_LENGTH = 512,
+    MAX_LINES = 1024,
+    MAGIC = 0xdeadbeefU
+};
+
+struct log_line {
+    struct timeval tv;
+    char line[MAX_LOG_LINE_LENGTH];
+};
+
+struct log {
+    struct { uint32_t first, len; } header;
+    struct log_line lines[MAX_LINES];
+    uint32_t magic;
+};
+
+void write_msg_to_log(struct log *log, const char *msg);
+int write_logs_to_file(const char *file_name, const struct log *log1, const struct log *log2);
+struct log *open_log(const char *file_name);
+
+#endif