[glibc/zack/no-nested-includes] Don’t include sys/select.h from sys/types.h.

[Zack Weinberg <zack@sourceware.org>]

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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=d19f158c2b06f162b8297c5560a28d9b7bb7c9f4

commit d19f158c2b06f162b8297c5560a28d9b7bb7c9f4
Author: Zack Weinberg <zackw@panix.com>
Date:   Sat Mar 16 12:35:25 2019 -0400

    Don’t include sys/select.h from sys/types.h.
    
    This is supposedly present for BSD compatibility, but the current
    generation of BSDs is not consistent about it: FreeBSD does, OpenBSD
    doesn’t, NetBSD exposes only fd_set and the FD_* macros.  Programs
    that need to wait for any of multiple I/O events have several
    alternatives to select nowadays, so I think it makes sense to expose
    select only to programs that specifically want it.
    
    Only a few places within our own code are affected.  A few test
    programs need to include sys/select.h explicitly, as does rpc/svc.h.
    sysdeps/nptl/thread_db.h needs to declare sigset_t, and
    sysdeps/unix/sysv/linux/pselect.c was including sys/poll.h instead of
    sys/select.h, which is probably a copy-and-paste error.  sys/socket.h
    needs to forward-declare struct timespec under __USE_GNU, because
    recvmmsg has a struct timespec * argument; I’m open to the possibility
    of having it fully declare struct timespec.
    
    I considered taking sys/select.h out of sys/time.h as well, but POSIX
    not only explicitly allows this inclusion, it requires sys/time.h to
    declare almost everything that sys/select.h declares.  It doesn’t seem
    worth creating another bits header just to prevent sys/time.h from
    declaring pselect, sigset_t, and struct timespec.
    
    	* posix/sys/types.h: Don’t include sys/select.h.
    	* scripts/check-obsolete-constructs.py: Remove whitelist entry
    	for sys/types.h -> sys/select.h.  Adjust commentary re
    	sys/time.h -> sys/select.h.
    
    	* socket/sys/socket.h: When __USE_GNU, forward-declare struct timespec.
    	* misc/tst-fdset.c, nptl/tst-cancel4.c, scripts/check-c++-types.sh
    	* sunrpc/rpc/svc.h: Include sys/select.h.
    	* sysdeps/nptl/thread_db.h: Include bits/types/sigset_t.h.
    	* sysdeps/unix/sysv/linux/pselect.c: Include sys/select.h,
    	not sys/poll.h.

Diff:
---
 misc/tst-fdset.c                     | 2 +-
 nptl/tst-cancel4.c                   | 1 +
 posix/sys/types.h                    | 3 ---
 scripts/check-c++-types.sh           | 1 +
 scripts/check-obsolete-constructs.py | 6 +++---
 socket/sys/socket.h                  | 4 ++++
 sunrpc/rpc/svc.h                     | 1 +
 sysdeps/nptl/thread_db.h             | 2 +-
 sysdeps/unix/sysv/linux/pselect.c    | 2 +-
 9 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/misc/tst-fdset.c b/misc/tst-fdset.c
index 70b7028..956e371 100644
--- a/misc/tst-fdset.c
+++ b/misc/tst-fdset.c
@@ -18,7 +18,7 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <stdio.h>
-#include <sys/types.h>
+#include <sys/select.h>
 
 static int
 do_test (void)
diff --git a/nptl/tst-cancel4.c b/nptl/tst-cancel4.c
index 60a965d..dce93dc 100644
--- a/nptl/tst-cancel4.c
+++ b/nptl/tst-cancel4.c
@@ -24,6 +24,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
+#include <sys/select.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <sys/ipc.h>
diff --git a/posix/sys/types.h b/posix/sys/types.h
index 8f6d328..3f29307 100644
--- a/posix/sys/types.h
+++ b/posix/sys/types.h
@@ -95,9 +95,6 @@ __BEGIN_DECLS
 
 /* In BSD <sys/types.h> is expected to define BYTE_ORDER.  */
 # include <endian.h>
-
-/* It also defines `fd_set' and the FD_* macros for `select'.  */
-# include <sys/select.h>
 #endif /* Use misc.  */
 
 __END_DECLS
diff --git a/scripts/check-c++-types.sh b/scripts/check-c++-types.sh
index a8f3cff..141ddf7 100755
--- a/scripts/check-c++-types.sh
+++ b/scripts/check-c++-types.sh
@@ -46,6 +46,7 @@ while read t; do
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/resource.h>
+#include <sys/select.h>
 #include <unistd.h>
 void foo ($t) { }
 EOF
diff --git a/scripts/check-obsolete-constructs.py b/scripts/check-obsolete-constructs.py
index fb63fe5..36d8746 100755
--- a/scripts/check-obsolete-constructs.py
+++ b/scripts/check-obsolete-constructs.py
@@ -538,13 +538,13 @@ HEADER_ALLOWED_INCLUDES = {
     # mandated: sys/msg.h -> sys/ipc.h
     #           sys/sem.h -> sys/ipc.h
     #           sys/shm.h -> sys/ipc.h
-    # allowed:  sys/time.h -> sys/select.h
-    #           sys/wait.h -> signal.h
+    #           sys/time.h -> sys/select.h (effectively)
+    # allowed:  sys/wait.h -> signal.h
     "sys/msg.h":                   [ "sys/ipc.h" ],
     "sys/sem.h":                   [ "sys/ipc.h" ],
     "sys/shm.h":                   [ "sys/ipc.h" ],
     "sys/time.h":                  [ "sys/select.h" ],
-    "sys/types.h":                 [ "endian.h", "sys/select.h" ],
+    "sys/types.h":                 [ "endian.h" ],
     "sys/uio.h":                   [ "sys/types.h" ],
     "sys/un.h":                    [ "string.h" ],
     "sys/wait.h":                  [ "signal.h" ],
diff --git a/socket/sys/socket.h b/socket/sys/socket.h
index 6f242d0..eebc9b5 100644
--- a/socket/sys/socket.h
+++ b/socket/sys/socket.h
@@ -36,6 +36,10 @@ __BEGIN_DECLS
 # include <bits/types/struct_osockaddr.h>
 #endif
 
+#ifdef __USE_GNU
+struct timespec;
+#endif
+
 /* The following constants should be used for the second parameter of
    `shutdown'.  */
 enum
diff --git a/sunrpc/rpc/svc.h b/sunrpc/rpc/svc.h
index 85d0183..c77dcf0 100644
--- a/sunrpc/rpc/svc.h
+++ b/sunrpc/rpc/svc.h
@@ -53,6 +53,7 @@
 
 #include <features.h>
 #include <rpc/rpc_msg.h>
+#include <sys/select.h>
 
 __BEGIN_DECLS
 
diff --git a/sysdeps/nptl/thread_db.h b/sysdeps/nptl/thread_db.h
index d134aca..4d949b0 100644
--- a/sysdeps/nptl/thread_db.h
+++ b/sysdeps/nptl/thread_db.h
@@ -26,7 +26,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 #include <sys/procfs.h>
-
+#include <bits/types/sigset_t.h>
 
 /* Error codes of the library.  */
 typedef enum
diff --git a/sysdeps/unix/sysv/linux/pselect.c b/sysdeps/unix/sysv/linux/pselect.c
index c9406ca..d1106e9 100644
--- a/sysdeps/unix/sysv/linux/pselect.c
+++ b/sysdeps/unix/sysv/linux/pselect.c
@@ -19,7 +19,7 @@
 #include <errno.h>
 #include <signal.h>
 #include <time.h>
-#include <sys/poll.h>
+#include <sys/select.h>
 #include <kernel-features.h>
 #include <sysdep-cancel.h>