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-rw-r--r--syslogd/proto.c177
1 files changed, 177 insertions, 0 deletions
diff --git a/syslogd/proto.c b/syslogd/proto.c
new file mode 100644
index 0000000..3487dbd
--- /dev/null
+++ b/syslogd/proto.c
@@ -0,0 +1,177 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * Copyright (C) 2018 - David Oberhollenzer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <stddef.h>
+#include <string.h>
+#include <ctype.h>
+#include <time.h>
+
+#include "proto.h"
+
+static const char *months[] = {
+ "Jan", "Feb", "Mar", "Apr",
+ "May", "Jun", "Jul", "Aug",
+ "Sep", "Oct", "Nov", "Dec"
+};
+
+static const int days[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+
+static int isleap(int year)
+{
+ return ((year % 4 == 0) && (year % 100 != 0)) || ((year % 400) == 0);
+}
+
+static int mdays(int year, int month)
+{
+ return (isleap(year) && month == 2) ? 29 : days[month - 1];
+}
+
+static char *read_num(char *str, int *out, int maxval)
+{
+ if (str == NULL || !isdigit(*str))
+ return NULL;
+ for (*out = 0; isdigit(*str); ++str) {
+ (*out) = (*out) * 10 + (*str) - '0';
+ if ((*out) > maxval)
+ return NULL;
+ }
+ return str;
+}
+
+static char *skip_space(char *str)
+{
+ if (str == NULL || !isspace(*str))
+ return NULL;
+ while (isspace(*str))
+ ++str;
+ return str;
+}
+
+static char *read_date_bsd(char *str, struct tm *tm)
+{
+ int year, month, day, hour, minute, second;
+ time_t t;
+
+ /* decode date */
+ for (month = 0; month < 12; ++month) {
+ if (strncmp(str, months[month], 3) == 0) {
+ str = skip_space(str + 3);
+ break;
+ }
+ }
+
+ str = read_num(str, &day, 31);
+ str = skip_space(str);
+
+ t = time(NULL);
+ if (localtime_r(&t, tm) == NULL)
+ return NULL;
+
+ year = tm->tm_year;
+
+ /* sanity check */
+ if (str == NULL || month >= 12 || day < 1)
+ return NULL;
+ if (month == 11 && tm->tm_mon == 0)
+ --year;
+ if (day > mdays(year + 1900, month + 1))
+ return NULL;
+
+ /* decode time */
+ str = read_num(str, &hour, 23);
+ if (str == NULL || *(str++) != ':')
+ return NULL;
+ str = read_num(str, &minute, 59);
+ if (str == NULL || *(str++) != ':')
+ return NULL;
+ str = read_num(str, &second, 59);
+ str = skip_space(str);
+
+ /* store result */
+ memset(tm, 0, sizeof(*tm));
+ tm->tm_sec = second;
+ tm->tm_min = minute;
+ tm->tm_hour = hour;
+ tm->tm_mday = day;
+ tm->tm_mon = month;
+ tm->tm_year = year;
+ return str;
+}
+
+static char *decode_priority(char *str, int *priority)
+{
+ while (isspace(*str))
+ ++str;
+ if (*(str++) != '<')
+ return NULL;
+ str = read_num(str, priority, 23 * 8 + 7);
+ if (str == NULL || *(str++) != '>')
+ return NULL;
+ while (isspace(*str))
+ ++str;
+ return str;
+}
+
+int syslog_msg_parse(syslog_msg_t *msg, char *str)
+{
+ char *ident, *ptr;
+ struct tm tstamp;
+ pid_t pid = 0;
+ int priority;
+
+ memset(msg, 0, sizeof(*msg));
+
+ str = decode_priority(str, &priority);
+ if (str == NULL)
+ return -1;
+
+ msg->facility = priority >> 3;
+ msg->level = priority & 0x07;
+
+ str = read_date_bsd(str, &tstamp);
+ if (str == NULL)
+ return -1;
+
+ ident = str;
+ while (*str != '\0' && *str != ':')
+ ++str;
+
+ if (*str == ':') {
+ *(str++) = '\0';
+ while (isspace(*str))
+ ++str;
+
+ ptr = ident;
+ while (*ptr != '[' && *ptr != '\0')
+ ++ptr;
+
+ if (*ptr == '[') {
+ *(ptr++) = '\0';
+
+ while (isdigit(*ptr))
+ pid = pid * 10 + *(ptr++) - '0';
+ }
+ } else {
+ ident = NULL;
+ }
+
+ msg->timestamp = mktime(&tstamp);
+ msg->pid = pid;
+ msg->ident = ident;
+ msg->message = str;
+ return 0;
+}