Add logging

The reason logFmt takes a timestamp as a parameter is to support IRCv3
server-time in the future to accurately log the znc buffer. Hopefully.

1 files changed, 121 insertions, 0 deletions

diff --git a/log.c b/log.c
new file mode 100644
index 0000000..2a47806
--- /dev/null
+++ b/log.c
@@ -0,0 +1,121 @@
+/* Copyright (C) 2018  Curtis McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sysexits.h>
+#include <time.h>
+
+#include "chat.h"
+
+static int logRoot = -1;
+
+static struct Log {
+	int dir;
+	int year;
+	int month;
+	int day;
+	FILE *file;
+} logs[TAGS_LEN];
+
+void logOpen(const char *path) {
+	logRoot = open(path, O_RDONLY | O_CLOEXEC);
+	if (logRoot < 0) err(EX_CANTCREAT, "%s", path);
+}
+
+static void sanitize(char *name) {
+	for (; name[0]; ++name) {
+		if (name[0] == '/') name[0] = '_';
+	}
+}
+
+static FILE *logFile(struct Tag tag, const struct tm *time) {
+	struct Log *log = &logs[tag.id];
+	if (
+		log->file
+		&& log->year == time->tm_year
+		&& log->month == time->tm_mon
+		&& log->day == time->tm_mday
+	) return log->file;
+
+	if (log->file) {
+		fclose(log->file);
+
+	} else {
+		char *name = strdup(tag.name);
+		if (!name) err(EX_OSERR, "strdup");
+		sanitize(name);
+
+		int error = mkdirat(logRoot, name, 0700);
+		if (error && errno != EEXIST) err(EX_CANTCREAT, "%s", name);
+
+		log->dir = openat(logRoot, name, O_RDONLY | O_CLOEXEC);
+		if (log->dir < 0) err(EX_CANTCREAT, "%s", name);
+
+		free(name);
+	}
+
+	log->year = time->tm_year;
+	log->month = time->tm_mon;
+	log->day = time->tm_mday;
+
+	char path[sizeof("YYYY-MM-DD.log")];
+	strftime(path, sizeof(path), "%F.log", time);
+	int fd = openat(
+		log->dir, path, O_WRONLY | O_APPEND | O_CREAT | O_CLOEXEC, 0700
+	);
+	if (fd < 0) err(EX_CANTCREAT, "%s/%s", tag.name, path);
+
+	log->file = fdopen(fd, "a");
+	if (!log->file) err(EX_CANTCREAT, "%s/%s", tag.name, path);
+	setlinebuf(log->file);
+
+	return log->file;
+}
+
+void logFmt(struct Tag tag, const time_t *ts, const char *format, ...) {
+	if (logRoot < 0) return;
+
+	time_t t;
+	if (!ts) {
+		t = time(NULL);
+		ts = &t;
+	}
+
+	struct tm *time = localtime(ts);
+	if (!time) err(EX_SOFTWARE, "localtime");
+
+	FILE *file = logFile(tag, time);
+
+	char stamp[sizeof("YYYY-MM-DDThh:mm:ss+hhmm")];
+	strftime(stamp, sizeof(stamp), "%FT%T%z", time);
+	fprintf(file, "[%s] ", stamp);
+	if (ferror(file)) err(EX_IOERR, "%s", tag.name);
+
+	va_list ap;
+	va_start(ap, format);
+	vfprintf(file, format, ap);
+	va_end(ap);
+	if (ferror(file)) err(EX_IOERR, "%s", tag.name);
+
+	fprintf(file, "\n");
+	if (ferror(file)) err(EX_IOERR, "%s", tag.name);
+}