src/network/sendmsg.c

   1 #include <sys/socket.h>
   2 #include <limits.h>
   3 #include <string.h>
   4 #include <errno.h>
   5 #include "syscall.h"
   6
   7 ssize_t sendmsg(int fd, const struct msghdr *msg, int flags)
   8 {
   9 #if LONG_MAX > INT_MAX
  10         struct msghdr h;
  11         /* Kernels before 2.6.38 set SCM_MAX_FD to 255, allocate enough
  12          * space to support an SCM_RIGHTS ancillary message with 255 fds.
  13          * Kernels since 2.6.38 set SCM_MAX_FD to 253. */
  14         struct cmsghdr chbuf[CMSG_SPACE(255*sizeof(int))/sizeof(struct cmsghdr)+1], *c;
  15         if (msg) {
  16                 h = *msg;
  17                 h.__pad1 = h.__pad2 = 0;
  18                 msg = &h;
  19                 if (h.msg_controllen) {
  20                         if (h.msg_controllen > sizeof chbuf) {
  21                                 errno = ENOMEM;
  22                                 return -1;
  23                         }
  24                         memcpy(chbuf, h.msg_control, h.msg_controllen);
  25                         h.msg_control = chbuf;
  26                         for (c=CMSG_FIRSTHDR(&h); c; c=CMSG_NXTHDR(&h,c))
  27                                 c->__pad1 = 0;
  28                 }
  29         }
  30 #endif
  31         return socketcall_cp(sendmsg, fd, msg, flags, 0, 0, 0);
  32 }