The variable "str" is used as both the source and destination in function
snprintf(), which is undefined behavior based on C11. The original description
in C11 is:
"If copying takes place between objects that
overlap, the behavior is undefined."
And, the function of ceph_osdmap_state_str() is to return the osdmap state, so
it should return "doesn't exist" when all the conditions are not satisfied. I
fix it in this patch.
Based on C11, snprintf() does nothing if n==0:
"If n is zero, nothing is written, and s may be a
null pointer. Otherwise, output characters beyond
the n-1st are discarded rather than being written to
the array, and a null character is written at the
end of the characters actually written into the
array."
so I remove the unnecessary check of len (because it is not a busy path and
saves a few lines of code).
Signed-off-by: Cong Ding <ding...@gmail.com>
---
net/ceph/osdmap.c | 27 ++++++++-------------------
1 file changed, 8 insertions(+), 19 deletions(-)
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index de73214..3131a99d3 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -13,26 +13,15 @@
char *ceph_osdmap_state_str(char *str, int len, int state)
{
- int flag = 0;
-
- if (!len)
- goto done;
-
- *str = '\0';
- if (state) {
- if (state & CEPH_OSD_EXISTS) {
- snprintf(str, len, "exists");
- flag = 1;
- }
- if (state & CEPH_OSD_UP) {
- snprintf(str, len, "%s%s%s", str, (flag ? ", " : ""),
- "up");
- flag = 1;
- }
- } else {
+ if ((state & CEPH_OSD_EXISTS) && (state & CEPH_OSD_UP))
+ snprintf(str, len, "exists, up");
+ else if (state & CEPH_OSD_EXISTS)
+ snprintf(str, len, "exists");
+ else if (state & CEPH_OSD_UP)
+ snprintf(str, len, "up");
+ else
snprintf(str, len, "doesn't exist");
- }
-done:
+
return str;
}
--
1.7.10.4
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