From 9a45f54310573c190fa270e1f80d8307750305e9 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Tue, 9 May 2017 20:01:01 +0000 Subject: Simplify recvmmsg code. Now we can assume a kernel with recvmmsg support, this patch simplifies the implementation to be similar to that for accept4: either using socketcall or the syscall according to whether the syscall is known to be available, without further fallback implementations. (In fact further simplification is possible, getting rid of the __ASSUME_*_SYSCALL_WITH_SOCKETCALL macros now that the minimum kernel is guaranteed support for all of accept4, recvmmsg, sendmmsg, whether through syscalls or through socketcall. I intend to do that for all of accept4 / recvmmsg / sendmmsg together - so making their implementations just like those for older socket functions - once the basic cleanup for 3.2 minimum kernel is done for sendmmsg as well as recvmmsg.) Tested for x86_64 and x86. * sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_RECVMMSG_SYSCALL): Define unconditionally. (__ASSUME_RECVMMSG_SOCKETCALL): Remove macro. (__ASSUME_RECVMMSG): Likewise. * sysdeps/unix/sysv/linux/recvmmsg.c (recvmmsg): Define using recvmmsg syscall if it can be assumed to be present, socketcall otherwise, with no fallback for runtime failure. --- sysdeps/unix/sysv/linux/kernel-features.h | 8 +--- sysdeps/unix/sysv/linux/recvmmsg.c | 70 ++++--------------------------- 2 files changed, 10 insertions(+), 68 deletions(-) (limited to 'sysdeps') diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h index 74ac6276e8..a5c226311c 100644 --- a/sysdeps/unix/sysv/linux/kernel-features.h +++ b/sysdeps/unix/sysv/linux/kernel-features.h @@ -90,13 +90,7 @@ /* Support for recvmmsg functionality was added in 2.6.33. The macros defined correspond to those for accept4. */ -#if __LINUX_KERNEL_VERSION >= 0x020621 -# ifdef __ASSUME_SOCKETCALL -# define __ASSUME_RECVMMSG_SOCKETCALL 1 -# endif -# define __ASSUME_RECVMMSG_SYSCALL 1 -# define __ASSUME_RECVMMSG 1 -#endif +#define __ASSUME_RECVMMSG_SYSCALL 1 /* statfs fills in f_flags since 2.6.36. */ #if __LINUX_KERNEL_VERSION >= 0x020624 diff --git a/sysdeps/unix/sysv/linux/recvmmsg.c b/sysdeps/unix/sysv/linux/recvmmsg.c index 28eb678428..de4412972b 100644 --- a/sysdeps/unix/sysv/linux/recvmmsg.c +++ b/sysdeps/unix/sysv/linux/recvmmsg.c @@ -21,73 +21,21 @@ #include #include +#include #include -/* Do not use the recvmmsg syscall on socketcall architectures unless - it was added at the same time as the socketcall support or can be - assumed to be present. */ -#if defined __ASSUME_SOCKETCALL \ - && !defined __ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL \ - && !defined __ASSUME_RECVMMSG_SYSCALL -# undef __NR_recvmmsg -#endif - -#ifdef __NR_recvmmsg -int -recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags, - struct timespec *tmo) -{ - return SYSCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo); -} -#elif defined __NR_socketcall -# include -# ifdef __ASSUME_RECVMMSG_SOCKETCALL int recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags, struct timespec *tmo) { + /* Do not use the recvmmsg syscall on socketcall architectures unless + it was added at the same time as the socketcall support or can be + assumed to be present. */ +#if defined __ASSUME_SOCKETCALL \ + && !defined __ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL \ + && !defined __ASSUME_RECVMMSG_SYSCALL return SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo); -} -# else -static int have_recvmmsg; - -int -recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags, - struct timespec *tmo) -{ - if (__glibc_likely (have_recvmmsg >= 0)) - { - int ret = SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, - tmo); - /* The kernel returns -EINVAL for unknown socket operations. - We need to convert that error to an ENOSYS error. */ - if (__builtin_expect (ret < 0, 0) - && have_recvmmsg == 0 - && errno == EINVAL) - { - /* Try another call, this time with an invalid file - descriptor and all other parameters cleared. This call - will not cause any harm and it will return - immediately. */ - ret = SOCKETCALL_CANCEL (invalid, -1); - if (errno == EINVAL) - { - have_recvmmsg = -1; - __set_errno (ENOSYS); - } - else - { - have_recvmmsg = 1; - __set_errno (EINVAL); - } - return -1; - } - return ret; - } - __set_errno (ENOSYS); - return -1; -} -# endif /* __ASSUME_RECVMMSG_SOCKETCALL */ #else -# include + return SYSCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo); #endif +} -- cgit 1.4.1