[LU-8854] liblustre should not define strlcpy or strlcat

Related — Tue, 27 Feb 2018 04:34:54 +0000

Currently, liblustre defines strlcpy and strlcat. This is problematic because some other libraries (which also shouldn't...) do this too, and then we can't link against them. (Notably, linking against SLURM libraries gets you libmunge, which defines them. So you can't link against liblustre and slurm.)

nm output for a recent-ish version of liblustre (the problem is the symbols marked "T", which are defined):
nm /lib64/liblustreapi.a | grep strl
U strlcat
U strlcpy
U strlen
U strlcpy
U strlen
U strlen
0000000000000060 T strlcat
0000000000000000 T strlcpy
U strlen

The solution is a fairly simple trick with #define, which lets us keep using the normal names without defining the symbols:
-size_t strlcpy(char *tgt, const char *src, size_t tgt_len);
+size_t ll_strlcpy(char *tgt, const char *src, size_t tgt_len);
+/* We must not export the strlcpy symbol from liblustre, hence this weirdness *
+#define strlcpy(a, b, c) ll_strlcpy(a, b, c)

Here's the resulting nm output:
nm ./lustre/utils/liblustreapi.a | grep strl
U ll_strlcat
U ll_strlcpy
U strlen
U ll_strlcpy
U strlen
U strlen
0000000000000000 T ll_strlcat
0000000000000090 T ll_strlcpy
U strlen

Patch coming shortly.

Whamcloud Community JIRA

[LU-8854] liblustre should not define strlcpy or strlcat