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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2022-01-27 16:45:18 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2022-01-28 18:18:27 -0300
commit948ce73b31fdb0860bcec4b8e62b14e88234f98a (patch)
tree587bed4b009d25b2304f75ba738b4a3235ad7e8e /include/sys
parent8fba672472ae0055387e9315fc2eddfa6775ca79 (diff)
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Linux: Only generate 64 bit timestamps for 64 bit time_t recvmsg/recvmmsg
The timestamps created by __convert_scm_timestamps only make sense for
64 bit time_t programs, 32 bit time_t programs will ignore 64 bit time_t
timestamps since SO_TIMESTAMP will be defined to old values (either by
glibc or kernel headers).

Worse, if the buffer is not suffice MSG_CTRUNC is set to indicate it
(which breaks some programs [1]).

This patch makes only 64 bit time_t recvmsg and recvmmsg to call
__convert_scm_timestamps.  Also, the assumption to called it is changed
from __ASSUME_TIME64_SYSCALLS to __TIMESIZE != 64 since the setsockopt
might be called by libraries built without __TIME_BITS=64.  The
MSG_CTRUNC is only set for the 64 bit symbols, it should happen only
if 64 bit time_t programs run older kernels.

Checked on x86_64-linux-gnu and i686-linux-gnu.

[1] https://github.com/systemd/systemd/pull/20567

Reviewed-by: Florian Weimer <fweimer@redhat.com>
Diffstat (limited to 'include/sys')
-rw-r--r--include/sys/socket.h10
1 files changed, 8 insertions, 2 deletions
diff --git a/include/sys/socket.h b/include/sys/socket.h
index a1d749f9fa..6e4cf5077f 100644
--- a/include/sys/socket.h
+++ b/include/sys/socket.h
@@ -98,15 +98,21 @@ extern int __sendmmsg (int __fd, struct mmsghdr *__vmessages,
 libc_hidden_proto (__sendmmsg)
 #endif
 
-/* Receive a message as described by MESSAGE from socket FD.
-   Returns the number of bytes read or -1 for errors.  */
 extern ssize_t __libc_recvmsg (int __fd, struct msghdr *__message,
 			       int __flags);
 extern ssize_t __recvmsg (int __fd, struct msghdr *__message,
 			  int __flags) attribute_hidden;
 #if __TIMESIZE == 64
+# define __libc_recvmsg64 __libc_recvmsg
+# define __recvmsg64  __recvmsg
 # define __recvmmsg64 __recvmmsg
 #else
+extern ssize_t __libc_recvmsg64 (int __fd, struct msghdr *__message,
+				 int __flags);
+extern ssize_t __recvmsg64 (int __fd, struct msghdr *__message,
+			    int __flags);
+/* Receive a message as described by MESSAGE from socket FD.
+   Returns the number of bytes read or -1 for errors.  */
 extern int __recvmmsg64 (int __fd, struct mmsghdr *vmessages,
 			 unsigned int vlen, int flags,
 			 struct __timespec64 *timeout);