[PATCH] Fix build issue due to Introduce nat/linux-namespaces.[ch] patch

Peter Bergner
2015-07-09T20:36:22Z

I have a toolchain that dies building gdb with the following error:

/home/bergner/binutils/binutils-gdb/gdb/nat/linux-namespaces.c:39:1: error: static declaration of ‘setns’ follows non-static declaration
setns (int fd, int nstype)
^
In file included from /opt/at7.0/include/sched.h:41:0,
from /home/bergner/binutils/binutils-gdb/gdb/nat/linux-namespaces.c:30:
/opt/at7.0/include/bits/sched.h:91:12: note: previous declaration of ‘setns’ was here
extern int setns (int __fd, int __nstype) __THROW;
^
make[2]: *** [linux-namespaces.o] Error 1

My configure doesn't define HAVE_SETNS because my glibc defines __stub_setns,
so nat/linux-namespaces.c defines its own setns routine. However, my glibc
also has its sched.h with a extern prototype for setns, which conflicts with
this static version linux-namespaces.c is creating, so we get the error above.
How about the following patch to work around the error? I can confirm that
it fixes the problem on my multiple systems that do and do not have setns.

Ok for trunk?

Peter

* nat/linux-namespaces.c (setns): Rename from this ...
(do_setns): ... to this. Support calling setns if it exists.
(mnsh_handle_setns): Call do_setns.

diff --git a/gdb/nat/linux-namespaces.c b/gdb/nat/linux-namespaces.c
index a7a3e4d..c2f0d2e 100644
--- a/gdb/nat/linux-namespaces.c
+++ b/gdb/nat/linux-namespaces.c
@@ -34,18 +34,20 @@ int debug_linux_namespaces;

/* Handle systems without setns. */

-#ifndef HAVE_SETNS
-static int
-setns (int fd, int nstype)
+static inline int
+do_setns (int fd, int nstype)
{
-#ifdef __NR_setns
- return syscall (__NR_setns, fd, nstype);
+#ifdef HAVE_SETNS
+ return setns (fd, nstype);
#else
+# ifdef __NR_setns
+ return syscall (__NR_setns, fd, nstype);
+# else
errno = ENOSYS;
return -1;
+# endif
#endif
}
-#endif

/* Handle systems without MSG_CMSG_CLOEXEC. */

@@ -495,7 +497,7 @@ mnsh_recv_message (int sock, enum mnsh_msg_type *type,
static ssize_t
mnsh_handle_setns (int sock, int fd, int nstype)
{
- int result = setns (fd, nstype);
+ int result = do_setns (fd, nstype);

return mnsh_return_int (sock, result, errno);
}