cr-restore: rseq: use glibc-specific way to unregister only as fallback

Let's use dynamic approach to detect built-in *libc rseq in all cases, and "old" static approach as a fallback path if the user kernel lacks support of ptrace_get_rseq_conf feature. Suggested-by: Florian Weimer <[email protected]> Signed-off-by: Alexander Mikhalitsyn <[email protected]>
checkpoint-restore · Aug 8, 2022 · db9781e · db9781e
1 parent f0b0a64
commit db9781e
Showing 1 changed file with 6 additions and 9 deletions.
diff --git a/criu/cr-restore.c b/criu/cr-restore.c
@@ -3088,31 +3088,28 @@ static int prep_rseq(struct rst_rseq_param *rseq, ThreadCoreEntry *tc)
 	return 0;
 }
 
-#if defined(__GLIBC__) && defined(RSEQ_SIG)
 static void prep_libc_rseq_info(struct rst_rseq_param *rseq)
 {
 	if (!kdat.has_rseq) {
 		rseq->rseq_abi_pointer = 0;
 		return;
 	}
 
-	rseq->rseq_abi_pointer = encode_pointer(__criu_thread_pointer() + __rseq_offset);
-	rseq->rseq_abi_size = __rseq_size;
-	rseq->signature = RSEQ_SIG;
-}
+	if (!kdat.has_ptrace_get_rseq_conf) {
+#if defined(__GLIBC__) && defined(RSEQ_SIG)
+		rseq->rseq_abi_pointer = encode_pointer(__criu_thread_pointer() + __rseq_offset);
+		rseq->rseq_abi_size = __rseq_size;
+		rseq->signature = RSEQ_SIG;
 #else
-static void prep_libc_rseq_info(struct rst_rseq_param *rseq)
-{
-	if (!kdat.has_rseq || !kdat.has_ptrace_get_rseq_conf) {
 		rseq->rseq_abi_pointer = 0;
+#endif
 		return;
 	}
 
 	rseq->rseq_abi_pointer = kdat.libc_rseq_conf.rseq_abi_pointer;
 	rseq->rseq_abi_size = kdat.libc_rseq_conf.rseq_abi_size;
 	rseq->signature = kdat.libc_rseq_conf.signature;
 }
-#endif
 
 static rlim_t decode_rlim(rlim_t ival)
 {