/*

 * Copyright (C) 2001-2003 FhG Fokus

 *

 * This file is part of opensips, a free SIP server.

 *

 * opensips is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version

 *

 * opensips is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA

 *

 * History:

 * --------

 *  2002-11-29  created by andrei

 *  2003-02-20  added solaris support (! HAVE_MSGHDR_MSG_CONTROL) (andrei)

 *  2003-11-03  added send_all, recv_all  and updated send/get_fd

 *               to handle signals  (andrei)

 */

#include <sys/types.h>

#include <sys/socket.h>

#include <sys/uio.h>

#include <stdlib.h> /* for NULL definition on openbsd */

#include <errno.h>

#include <string.h>

#include "../dprint.h"

/* receive all the data or returns error (handles EINTR etc.)

 * params: socket

 *         data     - buffer for the results

 *         data_len -

 *         flags    - recv flags for the first recv (see recv(2)), only

 *                    0, MSG_WAITALL and MSG_DONTWAIT make sense

 * if flags is set to MSG_DONWAIT (or to 0 and the socket fd is non-blocking),

 * and if no data is queued on the fd, recv_all will not wait (it will

 * return error and set errno to EAGAIN/EWOULDBLOCK). However if even 1 byte

 *  is queued, the call will block until the whole data_len was read or an

 *  error or eof occurred ("semi-nonblocking" behaviour,  some tcp code

 *   counts on it).

 * if flags is set to MSG_WAITALL it will block even if no byte is available.

 *

 * returns: bytes read or error (<0)

 * can return < data_len if EOF */

int recv_all(int socket, void* data, int data_len, int flags)

{

  int b_read;

  int n;

  b_read=0;

again:

  n=recv(socket, (char*)data, data_len, flags);

  if (n<0){

    /* error */

    if (errno==EINTR) goto again; /* signal, try again */

    /* on EAGAIN just return (let the caller know) */

    if ((errno==EAGAIN)||(errno==EWOULDBLOCK)) return n;

      LM_CRIT("1st recv on %d failed: %s\n", socket, strerror(errno));

      return n;

  }

  b_read+=n;

  while( (b_read!=data_len) && (n)){

    n=recv(socket, (char*)data+b_read, data_len-b_read, MSG_WAITALL);

    if (n<0){

      /* error */

      if (errno==EINTR) continue; /* signal, try again */

      LM_CRIT("2nd recv on %d failed: %s\n",

          socket, strerror(errno));

      return n;

    }

    b_read+=n;

  }

  return b_read;

}

/* sends all data (takes care of signals) (assumes blocking fd)

 * returns number of bytes sent or < 0 for an error */

int send_all(int socket, void* data, int data_len)

{

  int n;

again:

  n=send(socket, data, data_len, 0);

  if (n<0){

      /* error */

    if (errno==EINTR) goto again; /* signal, try again */

    LM_CRIT("send on %d failed: %s\n", socket, strerror(errno));

  }

  return n;

}

/* gcc does the right thing */

static inline int get_unaligned_int(const void *p)

{

  const struct { int d; } __attribute__((packed)) *pp = p;

  return pp->d;

}

/* gcc does the right thing */

static inline void put_unaligned_int(void *p, int value)

{

  struct { int d; } __attribute__((packed, may_alias)) *pp = p;

  pp->d = value;

}

/* at least 1 byte must be sent! */

int send_fd(int unix_socket, void* data, int data_len, int fd)

{

  struct msghdr msg;

  struct iovec iov[1];

  int ret;

#ifdef HAVE_MSGHDR_MSG_CONTROL

  struct cmsghdr* cmsg;

  /* make sure msg_control will point to properly aligned data */

  union {

    struct cmsghdr cm;

    char control[CMSG_SPACE(sizeof(fd))];

  }control_un;

  msg.msg_control=control_un.control;

  /* openbsd doesn't like "more space", msg_controllen must not

   * include the end padding */

  msg.msg_controllen=CMSG_LEN(sizeof(fd));

  cmsg=CMSG_FIRSTHDR(&msg);

  cmsg->cmsg_level = SOL_SOCKET;

  cmsg->cmsg_type = SCM_RIGHTS;

  cmsg->cmsg_len = CMSG_LEN(sizeof(fd));

  put_unaligned_int(CMSG_DATA(cmsg), fd);

  msg.msg_flags=0;

#else

  msg.msg_accrights=(caddr_t) &fd;

  msg.msg_accrightslen=sizeof(fd);

#endif

  msg.msg_name=0;

  msg.msg_namelen=0;

  iov[0].iov_base=data;

  iov[0].iov_len=data_len;

  msg.msg_iov=iov;

  msg.msg_iovlen=1;

again:

  ret=sendmsg(unix_socket, &msg, 0);

  if (ret<0){

    if (errno==EINTR) goto again;

    if (errno==EAGAIN || errno==EWOULDBLOCK) {

      LM_ERR("sendmsg would block on %d: %s\n",

        unix_socket, strerror(errno));

    } else {

      LM_CRIT("sendmsg failed on %d: %s\n",

        unix_socket, strerror(errno));

    }

  }

  return ret;

}

/* receives a fd and data_len data

 * params: unix_socket

 *         data

 *         data_len

 *         fd         - will be set to the passed fd value or -1 if no fd

 *                      was passed

 *         flags      - 0, MSG_DONTWAIT, MSG_WAITALL; same as recv_all flags

 * returns: bytes read on success, -1 on error (and sets errno) */

int receive_fd(int unix_socket, void* data, int data_len, int* fd, int flags)

{

  struct msghdr msg;

  struct iovec iov[1];

  int new_fd;

  int ret;

  int n;

#ifdef HAVE_MSGHDR_MSG_CONTROL

  struct cmsghdr* cmsg;

  union{

    struct cmsghdr cm;

    char control[CMSG_SPACE(sizeof(new_fd))];

  }control_un;

  msg.msg_control=control_un.control;

  msg.msg_controllen=sizeof(control_un.control);

#else

  msg.msg_accrights=(caddr_t) &new_fd;

  msg.msg_accrightslen=sizeof(int);

#endif

  msg.msg_name=0;

  msg.msg_namelen=0;

  iov[0].iov_base=data;

  iov[0].iov_len=data_len;

  msg.msg_iov=iov;

  msg.msg_iovlen=1;

  msg.msg_flags = 0;

again:

  ret=recvmsg(unix_socket, &msg, flags);

  if (ret<0){

    if (errno==EINTR) goto again;

    if ((errno==EAGAIN)||(errno==EWOULDBLOCK)) goto error;

    LM_CRIT("recvmsg on %d failed: %s\n", unix_socket, strerror(errno));

    goto error;

  }

  if (ret==0){

    /* EOF */

    LM_DBG("EOF on %d\n", unix_socket);

    goto error;

  }

  if (ret<data_len){

    LM_WARN("too few bytes read (%d from %d) trying to fix...\n",

        ret, data_len);

    /* blocking recv_all */

    n=recv_all(unix_socket, (char*)data+ret, data_len-ret, MSG_WAITALL);

    if (n>=0) ret+=n;

    else{

      ret=n;

      goto error;

    }

  }

#ifdef HAVE_MSGHDR_MSG_CONTROL

  cmsg=CMSG_FIRSTHDR(&msg);

  if ((cmsg!=0) && (cmsg->cmsg_len==CMSG_LEN(sizeof(new_fd)))){

    if (cmsg->cmsg_type!= SCM_RIGHTS){

      LM_ERR("msg control type != SCM_RIGHTS\n");

      ret=-1;

      goto error;

    }

    if (cmsg->cmsg_level!= SOL_SOCKET){

      LM_ERR("msg level != SOL_SOCKET\n");

      ret=-1;

      goto error;

    }

    *fd = get_unaligned_int(CMSG_DATA(cmsg));

  }else{

    /*

    LM_ERR("no descriptor passed, cmsg=%p,len=%d\n",

      cmsg, (unsigned)cmsg->cmsg_len); */

    *fd=-1;

    /* it's not really an error */

  }

#else

  if (msg.msg_accrightslen==sizeof(int)){

    *fd=new_fd;

  }else{

    /*LM_ERR("no descriptor passed, accrightslen=%d\n",

      msg.msg_accrightslen); */

    *fd=-1;

  }

#endif

error:

  return ret;

}