recvmmsg.c raw

   1  #define _GNU_SOURCE
   2  #include <sys/socket.h>
   3  #include <limits.h>
   4  #include <errno.h>
   5  #include <time.h>
   6  #include "syscall.h"
   7  
   8  #define IS32BIT(x) !((x)+0x80000000ULL>>32)
   9  #define CLAMP(x) (int)(IS32BIT(x) ? (x) : 0x7fffffffU+((0ULL+(x))>>63))
  10  
  11  hidden void __convert_scm_timestamps(struct msghdr *, socklen_t);
  12  
  13  int recvmmsg(int fd, struct mmsghdr *msgvec, unsigned int vlen, unsigned int flags, struct timespec *timeout)
  14  {
  15  #if LONG_MAX > INT_MAX
  16  	struct mmsghdr *mh = msgvec;
  17  	unsigned int i;
  18  	for (i = vlen; i; i--, mh++)
  19  		mh->msg_hdr.__pad1 = mh->msg_hdr.__pad2 = 0;
  20  #endif
  21  #ifdef SYS_recvmmsg_time64
  22  	time_t s = timeout ? timeout->tv_sec : 0;
  23  	long ns = timeout ? timeout->tv_nsec : 0;
  24  	int r = __syscall_cp(SYS_recvmmsg_time64, fd, msgvec, vlen, flags,
  25  			timeout ? ((long long[]){s, ns}) : 0);
  26  	if (SYS_recvmmsg == SYS_recvmmsg_time64 || r!=-ENOSYS)
  27  		return __syscall_ret(r);
  28  	if (vlen > IOV_MAX) vlen = IOV_MAX;
  29  	socklen_t csize[vlen];
  30  	for (int i=0; i<vlen; i++) csize[i] = msgvec[i].msg_hdr.msg_controllen;
  31  	r = __syscall_cp(SYS_recvmmsg, fd, msgvec, vlen, flags,
  32  		timeout ? ((long[]){CLAMP(s), ns}) : 0);
  33  	for (int i=0; i<r; i++)
  34  		__convert_scm_timestamps(&msgvec[i].msg_hdr, csize[i]);
  35  	return __syscall_ret(r);
  36  #else
  37  	return syscall_cp(SYS_recvmmsg, fd, msgvec, vlen, flags, timeout);
  38  #endif
  39  }
  40