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glibc  2.9
Defines | Functions
recvmsg.c File Reference
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <hurd.h>
#include <hurd/fd.h>
#include <hurd/socket.h>

Go to the source code of this file.

Defines

#define min(a, b)   ((a) > (b) ? (b) : (a))

Functions

ssize_t __libc_recvmsg (int fd, struct msghdr *message, int flags)

Define Documentation

#define min (   a,
  b 
)    ((a) > (b) ? (b) : (a))

Function Documentation

ssize_t __libc_recvmsg ( int  fd,
struct msghdr message,
int  flags 
)

Definition at line 30 of file recvmsg.c.

{
  error_t err;
  addr_port_t aport;
  char *data = NULL;
  mach_msg_type_number_t len = 0;
  mach_port_t *ports;
  mach_msg_type_number_t nports = 0;
  char *cdata = NULL;
  mach_msg_type_number_t clen = 0;
  size_t amount;
  char *buf;
  int i;

  /* Find the total number of bytes to be read.  */
  amount = 0;
  for (i = 0; i < message->msg_iovlen; i++)
    {
      amount += message->msg_iov[i].iov_len;

      /* As an optimization, we set the initial values of DATA and LEN
         from the first non-empty iovec.  This kicks-in in the case
         where the whole packet fits into that iovec buffer.  */
      if (data == NULL && message->msg_iov[i].iov_len > 0)
       {
         data = message->msg_iov[i].iov_base;
         len = message->msg_iov[i].iov_len;
       }
    }

  buf = data;
  if (err = HURD_DPORT_USE (fd, __socket_recv (port, &aport,
                                          flags, &data, &len,
                                          &ports, &nports,
                                          &cdata, &clen,
                                          &message->msg_flags, amount)))
    return __hurd_sockfail (fd, flags, err);

  if (message->msg_name != NULL)
    {
      char *buf = message->msg_name;
      mach_msg_type_number_t buflen = message->msg_namelen;
      int type;

      err = __socket_whatis_address (aport, &type, &buf, &buflen);
      if (err == EOPNOTSUPP)
       /* If the protocol server can't tell us the address, just return a
          zero-length one.  */
       {
         buf = message->msg_name;
         buflen = 0;
         err = 0;
       }

      if (err)
       {
         __mach_port_deallocate (__mach_task_self (), aport);
         return __hurd_sockfail (fd, flags, err);
       }

      if (message->msg_namelen > buflen)
       message->msg_namelen = buflen;

      if (buf != message->msg_name)
       {
         memcpy (message->msg_name, buf, message->msg_namelen);
         __vm_deallocate (__mach_task_self (), (vm_address_t) buf, buflen);
       }

      if (buflen > 0)
       ((struct sockaddr *) message->msg_name)->sa_family = type;
    }

  __mach_port_deallocate (__mach_task_self (), aport);

  if (buf == data)
    buf += len;
  else
    {
      /* Copy the data into MSG.  */
      if (len > amount)
       message->msg_flags |= MSG_TRUNC;
      else
       amount = len;

      buf = data;
      for (i = 0; i < message->msg_iovlen; i++)
       {
#define min(a, b)    ((a) > (b) ? (b) : (a))
         size_t copy = min (message->msg_iov[i].iov_len, amount);

         memcpy (message->msg_iov[i].iov_base, buf, copy);

         buf += copy;
         amount -= copy;
         if (len == 0)
           break;
       }

      __vm_deallocate (__mach_task_self (), (vm_address_t) data, len);
    }

  /* Copy the control message into MSG.  */
  if (clen > message->msg_controllen)
    message->msg_flags |= MSG_CTRUNC;
  else
    message->msg_controllen = clen;
  memcpy (message->msg_control, cdata, message->msg_controllen);

  __vm_deallocate (__mach_task_self (), (vm_address_t) cdata, clen);

  return (buf - data);
}

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