Quick patch for error when writing mem.lim default

When writing the system default for memory.limit_in_bytes (which is a LLONG_MAX)
the write fails. The number is equivalent to -1 (unlimited). So during dump,
store the number -1 instead.

Change-Id: Iafccc96bf5dbade763d7addaeda24194616e4d5f
Signed-off-by: Garrison Bellack <gbellack@google.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cgroup.c

@@ -302,6 +302,7 @@ static int read_cgroup_prop(struct cgroup_prop *property, const char *fullpath)
 {
 	char buf[100];
 	FILE *f;
+	char *endptr;
 
 	f = fopen(fullpath, "r");
 	if (!f) {
@@ -324,6 +325,14 @@ static int read_cgroup_prop(struct cgroup_prop *property, const char *fullpath)
 		return -1;
 	}
 
+	if (strtoll(buf, &endptr, 10) == LLONG_MAX)
+		strcpy(buf, "-1");
+
+	if (strcmp(endptr, "\n")) {
+		pr_perror("Failed parsing %s, with strtoll\n", buf);
+		return -1;
+	}
+
 	property->value = xstrdup(strip(buf));
 	if (!property->value)
 		return -1;