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glibc  2.9
Defines | Functions
sendmsg.c File Reference
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <hurd.h>
#include <hurd/fd.h>
#include <hurd/ifsock.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_sendmsg (int fd, const struct msghdr *message, int flags)

Define Documentation

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

Function Documentation

ssize_t __libc_sendmsg ( int  fd,
const struct msghdr message,
int  flags 
)

Definition at line 32 of file sendmsg.c.

{
  error_t err = 0;
  struct sockaddr_un *addr = message->msg_name;
  socklen_t addr_len = message->msg_namelen;
  addr_port_t aport = MACH_PORT_NULL;
  union
  {
    char *ptr;
    vm_address_t addr;
  } data = { .ptr = NULL };
  char data_buf[2048];
  mach_msg_type_number_t len;
  mach_msg_type_number_t amount;
  int dealloc = 0;
  int i;

  /* Find the total number of bytes to be written.  */
  len = 0;
  for (i = 0; i < message->msg_iovlen; i++)
    {
      if (message->msg_iov[i].iov_len > 0)
       {
         /* As an optimization, if we only have a single non-empty
             iovec, we set DATA and LEN from it.  */
         if (len == 0)
           data.ptr = message->msg_iov[i].iov_base;
         else
           data.ptr = NULL;

         len += message->msg_iov[i].iov_len;
       }
    }

  if (data.ptr == NULL)
    {
      size_t to_copy;
      char *buf;

      /* Allocate a temporary buffer to hold the data.  For small
         amounts of data, we allocate a buffer on the stack.  Larger
         amounts of data are stored in a page-aligned buffer.  The
         limit of 2048 bytes is inspired by the MiG stubs.  */
      if (len > 2048)
       {
         err = __vm_allocate (__mach_task_self (), &data.addr, len, 1);
         if (err)
           {
             __set_errno (err);
             return -1;
           }
         dealloc = 1;
       }
      else
       data.ptr = data_buf;

      /* Copy the data into DATA.  */
      to_copy = len;
      buf = data.ptr;
      for (i = 0; i < len; i++)
       {
#define       min(a, b)     ((a) > (b) ? (b) : (a))
         size_t copy = min (message->msg_iov[i].iov_len, to_copy);

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

         to_copy -= copy;
         if (to_copy == 0)
           break;
       }
    }

  if (addr)
    {
      if (addr->sun_family == AF_LOCAL)
       {
         /* For the local domain, we must look up the name as a file
            and talk to it with the ifsock protocol.  */
         file_t file = __file_name_lookup (addr->sun_path, 0, 0);
         if (file == MACH_PORT_NULL)
           return -1;
         err = __ifsock_getsockaddr (file, &aport);
         __mach_port_deallocate (__mach_task_self (), file);
         if (err == MIG_BAD_ID || err == EOPNOTSUPP)
           /* The file did not grok the ifsock protocol.  */
           err = ENOTSOCK;
         if (err)
           return __hurd_fail (err);
       }
      else
       err = EIEIO;
    }

  err = HURD_DPORT_USE (fd,
                     ({
                       if (err)
                         err = __socket_create_address (port,
                                                    addr->sun_family,
                                                    (char *) addr,
                                                    addr_len,
                                                    &aport);
                       if (! err)
                         {
                           /* Send the data.  */
                           err = __socket_send (port, aport,
                                             flags, data.ptr, len,
                                             NULL,
                                             MACH_MSG_TYPE_COPY_SEND, 0,
                                             message->msg_control,
                                             message->msg_controllen,
                                             &amount);
                           __mach_port_deallocate (__mach_task_self (),
                                                aport);
                         }
                       err;
                     }));

  if (dealloc)
    __vm_deallocate (__mach_task_self (), data.addr, len);

  return err ? __hurd_sockfail (fd, flags, err) : amount;
}

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