Re: asm-generic/unistd.h and glibc use of NR_ipc

[Linas Vepstas <linasvepstas at gmail dot com>]

Hi Chris,

A question, and a patch follow:

On 28 September 2010 08:05, Chris Metcalf <cmetcalf@tilera.com> wrote:
> Â(Adding libc-ports to the cc list.)
>
> On 9/28/2010 4:40 AM, Arnd Bergmann wrote:
>> Chris Metcalf is using the generic unistd.h file on the tile architecture
>> and has a glibc port that should be easily portable to all future
>> architectures. There are a few of them getting ready to be merged
>> now (c6x, lm32, nios2, and some people have contacted me privately
>> for architectures I cannot name).
>>
>> I expect that all of them will just use the same syscall ABI and glibc
>> port.
>
> I'm happy to provide some previews of the work I'm doing to interested parties.
[...]

> sysdeps/unix/sysv/linux/generic/access.c
> sysdeps/unix/sysv/linux/generic/bits/fcntl.h
> sysdeps/unix/sysv/linux/generic/bits/sem.h
> sysdeps/unix/sysv/linux/generic/bits/stat.h
> sysdeps/unix/sysv/linux/generic/bits/typesizes.h
> sysdeps/unix/sysv/linux/generic/chmod.c
> sysdeps/unix/sysv/linux/generic/chown.c
> sysdeps/unix/sysv/linux/generic/lxstat.c
> sysdeps/unix/sysv/linux/generic/xstat.c
> sysdeps/unix/sysv/linux/generic/Versions
> sysdeps/unix/sysv/linux/generic/fxstatat.c
> sysdeps/unix/sysv/linux/generic/lchown.c
> sysdeps/unix/sysv/linux/generic/link.c
> sysdeps/unix/sysv/linux/generic/readlink.c
> sysdeps/unix/sysv/linux/generic/open.c
> sysdeps/unix/sysv/linux/generic/open64.c
> sysdeps/unix/sysv/linux/generic/pipe.c
> sysdeps/unix/sysv/linux/generic/poll.c
> sysdeps/unix/sysv/linux/generic/recv.c
> sysdeps/unix/sysv/linux/generic/rmdir.c
> sysdeps/unix/sysv/linux/generic/send.c
> sysdeps/unix/sysv/linux/generic/symlink.c
> sysdeps/unix/sysv/linux/generic/syscalls.list
> sysdeps/unix/sysv/linux/generic/sysdep.h
> sysdeps/unix/sysv/linux/generic/unlink.c
> sysdeps/unix/sysv/linux/generic/xmknod.c
> sysdeps/unix/sysv/linux/generic/sysctl.c
> sysdeps/unix/sysv/linux/generic/readlink_chk.c
> sysdeps/unix/sysv/linux/generic/ustat.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/fcntl.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/fstatfs.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/ftruncate.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/fxstat.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/mmap.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/posix_fadvise.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/sendfile.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/statfs.c
> sysdeps/unix/sysv/linux/generic/wordsize-32/truncate.c
> sysdeps/unix/sysv/linux/generic/brk.c
> sysdeps/unix/sysv/linux/generic/dl-origin.c
> sysdeps/unix/sysv/linux/generic/umount.c
> sysdeps/unix/sysv/linux/generic/creat.c
> sysdeps/unix/sysv/linux/generic/pause.c
> sysdeps/unix/sysv/linux/generic/Makefile
> sysdeps/unix/sysv/linux/generic/select.c
> sysdeps/unix/sysv/linux/generic/epoll_create.c
> sysdeps/unix/sysv/linux/generic/epoll_wait.c
> sysdeps/unix/sysv/linux/generic/inotify_init.c
> sysdeps/unix/sysv/linux/generic/dup2.c
> sysdeps/unix/sysv/linux/generic/mkdir.c
> sysdeps/unix/sysv/linux/generic/rename.c
> sysdeps/unix/sysv/linux/generic/utimes.c

I note that this hasn't been merged into glibc-2.13, any particular
explaintation
for that?

Anyway, it seems that pthread cancellation pints are missing
from a couple of the functions.  e.g. for send, recv, one needs
the following:

Index: glibc-2.13/sysdeps/unix/sysv/linux/generic/send.c
===================================================================
--- glibc-2.13.orig/sysdeps/unix/sysv/linux/generic/send.c	2011-03-10
10:26:48.000000000 -0600
+++ glibc-2.13/sysdeps/unix/sysv/linux/generic/send.c	2011-03-10
10:26:55.000000000 -0600
@@ -18,12 +18,25 @@

 #include <stdlib.h>
 #include <sys/types.h>
-#include <sysdep.h>
+#include <sysdep-cancel.h>
 #include <libc-symbols.h>

 ssize_t __libc_send(int sockfd, const void *buffer, size_t len, int flags)
 {
-  return INLINE_SYSCALL (sendto, 6, sockfd, buffer, len, flags, NULL, 0);
+  ssize_t result;
+
+  if (SINGLE_THREAD_P)
+    result = INLINE_SYSCALL (sendto, 6, sockfd, buffer, len, flags, NULL, 0);
+  else
+    {
+      int oldtype = LIBC_CANCEL_ASYNC ();
+
+      result = INLINE_SYSCALL (sendto, 6, sockfd, buffer, len, flags, NULL, 0);
+
+      LIBC_CANCEL_RESET (oldtype);
+    }
+
+  return result;
 }

 strong_alias (__libc_send, __send)

and likewise for recv ...

--linas