More checks for localtime() and gmtime() returning NULL.

And some comments in the case where we're converting the result of
time() - if your machine's idea of time predates January 1, 1970,
00:00:00 UTC, it'll crash on Windows, but that's not a case where a
*file* can cause the problem due either to a bad file time stamp or bad
time stamps in the file.

Change-Id: I837a438e4b875dd8c4f3ec2137df7a16ee4e9498
Reviewed-on: https://code.wireshark.org/review/18369
Reviewed-by: Guy Harris <guy@alum.mit.edu>

7 files changed, 76 insertions, 43 deletions

diff --git a/ui/gtk/fileset_dlg.c b/ui/gtk/fileset_dlg.c
index bb0e04d7fe..cc28f2b152 100644
--- a/ui/gtk/fileset_dlg.c
+++ b/ui/gtk/fileset_dlg.c
@@ -160,15 +160,23 @@ fileset_dlg_add_file(fileset_entry *entry, void *window _U_) {
         /* if this file doesn't follow the file set pattern, */
         /* use the creation time of that file */
         local = localtime(&entry->ctime);
-        created = g_strdup_printf("%04u-%02u-%02u %02u:%02u:%02u",
-                                  local->tm_year+1900, local->tm_mon+1, local->tm_mday,
-                                  local->tm_hour, local->tm_min, local->tm_sec);
+        if (local != NULL) {
+            created = g_strdup_printf("%04u-%02u-%02u %02u:%02u:%02u",
+                                      local->tm_year+1900, local->tm_mon+1, local->tm_mday,
+                                      local->tm_hour, local->tm_min, local->tm_sec);
+        } else {
+            created = g_strdup("Time not representable");
+        }
     }
 
     local = localtime(&entry->mtime);
-    modified = g_strdup_printf("%04u-%02u-%02u %02u:%02u:%02u",
-        local->tm_year+1900, local->tm_mon+1, local->tm_mday,
-        local->tm_hour, local->tm_min, local->tm_sec);
+    if (local != NULL) {
+        modified = g_strdup_printf("%04u-%02u-%02u %02u:%02u:%02u",
+            local->tm_year+1900, local->tm_mon+1, local->tm_mday,
+            local->tm_hour, local->tm_min, local->tm_sec);
+    } else {
+        modified = g_strdup("Time not representable");
+    }
     size = g_strdup_printf("%" G_GINT64_MODIFIER "d Bytes", entry->size);
 
     fs_rb = gtk_radio_button_new_with_label_from_widget(
diff --git a/ui/gtk/iax2_analysis.c b/ui/gtk/iax2_analysis.c
index f8b45d1c75..d4ade50f23 100644
--- a/ui/gtk/iax2_analysis.c
+++ b/ui/gtk/iax2_analysis.c
@@ -516,14 +516,21 @@ static int iax2_packet_add_info(GtkWidget *list, user_data_t * user_data,
 	then = pinfo->abs_ts.secs;
 	msecs = (guint16)(pinfo->abs_ts.nsecs/1000000);
 	tm_tmp = localtime(&then);
-	g_snprintf(timeStr,sizeof(timeStr),"%02d/%02d/%04d %02d:%02d:%02d.%03d",
-		tm_tmp->tm_mon + 1,
-		tm_tmp->tm_mday,
-		tm_tmp->tm_year + 1900,
-		tm_tmp->tm_hour,
-		tm_tmp->tm_min,
-		tm_tmp->tm_sec,
-		msecs);
+	if (tm_tmp != NULL) {
+		/*
+		 * XXX - somewhat US-centric here.
+		 */
+		g_snprintf(timeStr,sizeof(timeStr),"%02d/%02d/%04d %02d:%02d:%02d.%03d",
+			tm_tmp->tm_mon + 1,
+			tm_tmp->tm_mday,
+			tm_tmp->tm_year + 1900,
+			tm_tmp->tm_hour,
+			tm_tmp->tm_min,
+			tm_tmp->tm_sec,
+			msecs);
+	} else {
+		g_snprintf(timeStr,sizeof(timeStr),"XX/XX/XXXX XX:XX:XX.XXX",
+	}
 
 	/* Default to using black on white text if nothing below overrides it */
 	g_snprintf(color_str,sizeof(color_str),"#ffffffffffff");
diff --git a/ui/gtk/io_stat.c b/ui/gtk/io_stat.c
index 7f3f4eee7c..2f16332506 100644
--- a/ui/gtk/io_stat.c
+++ b/ui/gtk/io_stat.c
@@ -488,15 +488,18 @@ print_interval_string(char *buf, int buf_len, guint32 interval, io_stat_t *io,
             nsec_val -= 1000;
         }
         tmp = localtime (&sec_val);
-        if (io->interval >= 1000) {
-            g_snprintf(buf, buf_len, "%02d:%02d:%02d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
-        } else if (io->interval >= 100) {
-            g_snprintf(buf, buf_len, "%02d:%02d:%02d.%1d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val/100);
-        } else if (io->interval >= 10) {
-            g_snprintf(buf, buf_len, "%02d:%02d:%02d.%02d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val/10);
-        } else {
-            g_snprintf(buf, buf_len, "%02d:%02d:%02d.%03d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val);
-        }
+        if (tmp != NULL) {
+            if (io->interval >= 1000) {
+                g_snprintf(buf, buf_len, "%02d:%02d:%02d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+            } else if (io->interval >= 100) {
+                g_snprintf(buf, buf_len, "%02d:%02d:%02d.%1d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val/100);
+            } else if (io->interval >= 10) {
+                g_snprintf(buf, buf_len, "%02d:%02d:%02d.%02d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val/10);
+            } else {
+                g_snprintf(buf, buf_len, "%02d:%02d:%02d.%03d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val);
+            }
+        } else
+            g_snprintf(buf, buf_len, "Time not representable");
     } else {
         if (!ext) {
             g_snprintf(buf, buf_len, "%d.%03d", interval/1000,interval%1000);
diff --git a/ui/gtk/main_welcome.c b/ui/gtk/main_welcome.c
index 696446f7b4..5debeb0fa0 100644
--- a/ui/gtk/main_welcome.c
+++ b/ui/gtk/main_welcome.c
@@ -330,7 +330,7 @@ welcome_header_set_message(gchar *msg) {
     if (msg) {
         g_string_append(message, msg);
     } else { /* Use our default header */
-        if ((now->tm_mon == 3 && now->tm_mday == 1) || (now->tm_mon == 6 && now->tm_mday == 14)) {
+        if (now != NULL && ((now->tm_mon == 3 && now->tm_mday == 1) || (now->tm_mon == 6 && now->tm_mday == 14))) {
             g_string_append(message, "Sniffing the glue that holds the Internet together");
         } else {
             g_string_append(message, prefs.gui_start_title);
diff --git a/ui/gtk/memory_dlg.c b/ui/gtk/memory_dlg.c
index af06667076..d11122c2ae 100644
--- a/ui/gtk/memory_dlg.c
+++ b/ui/gtk/memory_dlg.c
@@ -130,15 +130,18 @@ print_interval_string(char *buf, int buf_len, guint32 interval, io_stat_t *io)
         nsec_val -= 1000;
     }
     tmp = localtime (&sec_val);
-    if (INTERVAL >= 1000) {
-        g_snprintf(buf, buf_len, "%02d:%02d:%02d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
-    } else if (INTERVAL >= 100) {
-        g_snprintf(buf, buf_len, "%02d:%02d:%02d.%1d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val/100);
-    } else if (INTERVAL >= 10) {
-        g_snprintf(buf, buf_len, "%02d:%02d:%02d.%02d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val/10);
-    } else {
-        g_snprintf(buf, buf_len, "%02d:%02d:%02d.%03d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val);
-    }
+    if (tmp != NULL) {
+        if (INTERVAL >= 1000) {
+            g_snprintf(buf, buf_len, "%02d:%02d:%02d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+        } else if (INTERVAL >= 100) {
+            g_snprintf(buf, buf_len, "%02d:%02d:%02d.%1d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val/100);
+        } else if (INTERVAL >= 10) {
+            g_snprintf(buf, buf_len, "%02d:%02d:%02d.%02d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val/10);
+        } else {
+            g_snprintf(buf, buf_len, "%02d:%02d:%02d.%03d", tmp->tm_hour, tmp->tm_min, tmp->tm_sec, nsec_val);
+        }
+    } else
+        g_snprintf(buf, buf_len, "XX:XX:XX");
 }
 
 static void
diff --git a/ui/gtk/rtp_analysis.c b/ui/gtk/rtp_analysis.c
index 239f8569da..0089624909 100644
--- a/ui/gtk/rtp_analysis.c
+++ b/ui/gtk/rtp_analysis.c
@@ -570,14 +570,20 @@ rtp_packet_add_info(GtkWidget *list, user_data_t * user_data,
 	then = pinfo->abs_ts.secs;
 	msecs = (guint16)(pinfo->abs_ts.nsecs/1000000);
 	tm_tmp = localtime(&then);
-	g_snprintf(timeStr, sizeof(timeStr), "%02d/%02d/%04d %02d:%02d:%02d.%03d",
-		tm_tmp->tm_mon + 1,
-		tm_tmp->tm_mday,
-		tm_tmp->tm_year + 1900,
-		tm_tmp->tm_hour,
-		tm_tmp->tm_min,
-		tm_tmp->tm_sec,
-		msecs);
+	if (tm_tmp != NULL) {
+		/*
+		 * XXX - somewhat US-centric.
+		 */
+		g_snprintf(timeStr, sizeof(timeStr), "%02d/%02d/%04d %02d:%02d:%02d.%03d",
+			tm_tmp->tm_mon + 1,
+			tm_tmp->tm_mday,
+			tm_tmp->tm_year + 1900,
+			tm_tmp->tm_hour,
+			tm_tmp->tm_min,
+			tm_tmp->tm_sec,
+			msecs);
+	} else
+		g_snprintf(timeStr, sizeof(timeStr), "XX/XX/XXXX XX:XX:XX.XXX");
 
 	/* Default to using black on white text if nothing below overrides it */
 	g_snprintf(color_str, sizeof(color_str), "#ffffffffffff");
diff --git a/ui/gtk/rtp_player.c b/ui/gtk/rtp_player.c
index 7d051093ad..aaa029a51e 100644
--- a/ui/gtk/rtp_player.c
+++ b/ui/gtk/rtp_player.c
@@ -1303,7 +1303,10 @@ channel_draw(rtp_channel_info_t *rci)
 			if(gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(cb_view_as_time_of_day))) {
 				seconds = rci->start_time_abs.secs + i * MULT / sample_rate;
 				timestamp = localtime(&seconds);
-				g_snprintf(label_string, MAX_TIME_LABEL, "%02d:%02d:%02d", timestamp->tm_hour, timestamp->tm_min, timestamp->tm_sec);
+				if (timestamp != NULL
+					g_snprintf(label_string, MAX_TIME_LABEL, "%02d:%02d:%02d", timestamp->tm_hour, timestamp->tm_min, timestamp->tm_sec);
+				else
+					g_snprintf(label_string, MAX_TIME_LABEL, "XX:XX:XX");
 			} else {
 				g_snprintf(label_string, MAX_TIME_LABEL, "%.0f s", floor(nstime_to_sec(&rci->start_time_abs)) + i*MULT/sample_rate);
 			}
@@ -1451,7 +1454,10 @@ channel_draw(rtp_channel_info_t *rci)
 				if(gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(cb_view_as_time_of_day))) {
 					seconds = rci->start_time_abs.secs + i * MULT / sample_rate;
 					timestamp = localtime(&seconds);
-					g_snprintf(label_string, MAX_TIME_LABEL, "%02d:%02d:%02d", timestamp->tm_hour, timestamp->tm_min, timestamp->tm_sec);
+					if (timestamp != NULL)
+						g_snprintf(label_string, MAX_TIME_LABEL, "%02d:%02d:%02d", timestamp->tm_hour, timestamp->tm_min, timestamp->tm_sec);
+					else
+						g_snprintf(label_string, MAX_TIME_LABEL, "XX:XX:XX");
 				} else {
 					g_snprintf(label_string, MAX_TIME_LABEL, "%.0f s", floor(nstime_to_sec(&rci->start_time_abs)) + i*MULT/sample_rate);
 				}