in_kmsg: fix /dev/kmsg parsing

* use strtoul for priority since it is unsigned
* check for overflow correctly by comparing against ULONG_MAX
* fail if no digits were consumed or next character is not comma
* calculate tv.tv_usec correctly in case tv.tv_sec 32-bit
* remove redundant errno = 0 added in 3254b9a
* remove erroneous time.h added with 72d9dc8

Signed-off-by: Erik Karlsson <erik.karlsson@iopsys.eu>

Author: Erik Karlsson

plugins/in_kmsg/in_kmsg.c

@@ -36,7 +36,6 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <inttypes.h>
-#include <time.h>
 
 #include "in_kmsg.h"
 
@@ -114,7 +113,6 @@ static inline int process_line(const char *line,
     struct timeval tv;       /* time value                  */
     int line_len;
     uint64_t val;
-    long pri_val;
     const char *p = line;
     char *end = NULL;
     struct flb_time ts;
@@ -124,14 +122,19 @@ static inline int process_line(const char *line,
     ctx->buffer_id++;
 
     errno = 0;
-    pri_val = strtol(p, &end, 10);
-    if ((errno == ERANGE && (pri_val == INT_MAX || pri_val == INT_MIN))
-        || (errno != 0 && pri_val == 0)) {
+    val = strtoul(p, &end, 10);
+    if ((errno == ERANGE && val == ULONG_MAX)
+        || (errno != 0 && val == 0)) {
+        goto fail;
+    }
+
+    /* ensure something was consumed */
+    if (end == p) {
         goto fail;
     }
 
     /* Priority */
-    priority = FLB_KLOG_PRI(pri_val);
+    priority = FLB_KLOG_PRI(val);
 
     if (priority > ctx->prio_level) {
         /* Drop line */
@@ -145,13 +148,18 @@ static inline int process_line(const char *line,
     }
     p++;
 
-    errno = 0;
     val = strtoull(p, &end, 10);
     if ((errno == ERANGE && val == ULLONG_MAX)
         || (errno != 0 && val == 0)) {
         goto fail;
     }
 
+    /* make sure strtoull consumed something */
+    /* after the sequence number, the next char must be ',' */
+    if (end == p || *end != ',') {
+        goto fail;
+    }
+
     sequence = val;
     p = ++end;
 
@@ -162,8 +170,13 @@ static inline int process_line(const char *line,
         goto fail;
     }
 
+    /* ensure something was consumed */
+    if (end == p) {
+        goto fail;
+    }
+
     tv.tv_sec  = val/1000000;
-    tv.tv_usec = val - (tv.tv_sec * 1000000);
+    tv.tv_usec = val - ((uint64_t)tv.tv_sec * 1000000);
 
     flb_time_set(&ts, ctx->boot_time.tv_sec + tv.tv_sec, tv.tv_usec * 1000);