From: Sebastien GODARD <sysstat@users.noreply.github.com>
Date: Sat, 30 Dec 2017 10:16:32 +0000 (+0100)
Subject: sadc: Fix segfault that may happen when appending data to file
X-Git-Tag: v11.7.1~18
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=1cf6596368da94ac48656dbb117f4e8c0cde58b9;p=sysstat

sadc: Fix segfault that may happen when appending data to file

Buffers need to be allocated according to activities present in file so
that we can append data to that file.

Signed-off-by: Sebastien GODARD <sysstat@users.noreply.github.com>
---

diff --git a/sadc.c b/sadc.c
index c96d134..edc7085 100644
--- a/sadc.c
+++ b/sadc.c
@@ -936,20 +936,6 @@ void open_ofile(int *ofd, char ofile[], int restart_mark)
 
 		p = get_activity_position(act, file_act[i].id, EXIT_IF_NOT_FOUND);
 
-		/*
-		 * Force number of sub-items to that of the file, and reallocate structures.
-		 * We don't care for items as their structures will be dynamically allocated.
-		 */
-		if (file_act[i].nr2 != act[p]->nr2) {
-			act[p]->nr2 = file_act[i].nr2;
-			SREALLOC(act[p]->_buf0, void,
-				 (size_t) act[p]->msize * (size_t) act[p]->nr_ini * (size_t) act[p]->nr2);
-		}
-
-		/* Save activity sequence */
-		id_seq[i] = file_act[i].id;
-		act[p]->options |= AO_COLLECTED;
-
 		/*
 		 * sar doesn't expect a number of items equal to 0.
 		 * Yet @nr_ini may be 0 if no items have been found on current machine.
@@ -958,6 +944,21 @@ void open_ofile(int *ofd, char ofile[], int restart_mark)
 		 * the machine.
 		 */
 		act[p]->nr_ini = file_act[i].nr;
+
+		/*
+		 * Force number of sub-items to that of the file, and reallocate structures.
+		 * Note: Structures have been allocated in sa_sys_init() only for activities
+		 * that are collected. But since activities from file now prevail over them,
+		 * we need to reallocate.
+		 */
+		act[p]->nr2 = file_act[i].nr2;
+		SREALLOC(act[p]->_buf0, void,
+			 (size_t) act[p]->msize * (size_t) act[p]->nr_ini * (size_t) act[p]->nr2);
+		act[p]->nr_allocated = act[p]->nr_ini;
+
+		/* Save activity sequence */
+		id_seq[i] = file_act[i].id;
+		act[p]->options |= AO_COLLECTED;
 	}
 
 	return;