src/network/recvmmsg.c

   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 }