niceSOFT/libssh | Gitverse

src/scp.c
835 строк23 KB
Andreas Schneider
Remove vim modelines from all files
28 июн 2018, 09:41
28 июн 2018, 09:41c563ed6
/*
 * scp - SSH scp wrapper functions
 *
 * This file is part of the SSH Library
 *
 * Copyright (c) 2009 by Aris Adamantiadis <aris@0xbadc0de.be>
 *
 * The SSH Library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 *
 * The SSH Library 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 Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the SSH Library; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

#include "config.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "libssh/priv.h"
#include "libssh/scp.h"

/**
 * @defgroup libssh_scp The SSH scp functions
 * @ingroup libssh
 *
 * SCP protocol over SSH functions
 *
 * @{
 */

/**
 * @brief Create a new scp session.
 *
 * @param[in]  session  The SSH session to use.
 *
 * @param[in]  mode     One of SSH_SCP_WRITE or SSH_SCP_READ, depending if you
 *                      need to drop files remotely or read them.
 *                      It is not possible to combine read and write.
 *                      SSH_SCP_RECURSIVE Flag can be or'ed to this to indicate
 *                      that you're going to use recursion. Browsing through
 *                      directories is not possible without this.
 *
 * @param[in]  location The directory in which write or read will be done. Any
 *                      push or pull will be relative to this place.
 *                      This can also be a pattern of files to download (read).
 *
 * @returns             A ssh_scp handle, NULL if the creation was impossible.
 */
ssh_scp ssh_scp_new(ssh_session session, int mode, const char *location){
  ssh_scp scp=malloc(sizeof(struct ssh_scp_struct));
  if(scp == NULL){
    ssh_set_error(session,SSH_FATAL,"Error allocating memory for ssh_scp");
    return NULL;
  }
  ZERO_STRUCTP(scp);
  if((mode&~SSH_SCP_RECURSIVE) != SSH_SCP_WRITE && (mode &~SSH_SCP_RECURSIVE) != SSH_SCP_READ){
    ssh_set_error(session,SSH_FATAL,"Invalid mode %d for ssh_scp_new()",mode);
    ssh_scp_free(scp);
    return NULL;
  }
  scp->location=strdup(location);
  if (scp->location == NULL) {
    ssh_set_error(session,SSH_FATAL,"Error allocating memory for ssh_scp");
    ssh_scp_free(scp);
    return NULL;
  }
  scp->session=session;
  scp->mode=mode & ~SSH_SCP_RECURSIVE;
  scp->recursive = (mode & SSH_SCP_RECURSIVE) != 0;
  scp->channel=NULL;
  scp->state=SSH_SCP_NEW;
  return scp;
}

/**
 * @brief Initialize the scp channel.
 *
 * @param[in]  scp      The scp context to initialize.
 *
 * @return SSH_OK on success or an SSH error code.
 *
 * @see ssh_scp_new()
 */
int ssh_scp_init(ssh_scp scp)
{
  int r;
  char execbuffer[1024];
  uint8_t code;
  if(scp==NULL)
      return SSH_ERROR;
  if(scp->state != SSH_SCP_NEW){
    ssh_set_error(scp->session,SSH_FATAL,"ssh_scp_init called under invalid state");
    return SSH_ERROR;
  }
  SSH_LOG(SSH_LOG_PROTOCOL,"Initializing scp session %s %son location '%s'",
		  scp->mode==SSH_SCP_WRITE?"write":"read",
				  scp->recursive?"recursive ":"",
						  scp->location);
  scp->channel=ssh_channel_new(scp->session);
  if(scp->channel == NULL){
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  r= ssh_channel_open_session(scp->channel);
  if(r==SSH_ERROR){
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  if(scp->mode == SSH_SCP_WRITE)
    snprintf(execbuffer,sizeof(execbuffer),"scp -t %s %s",
    		scp->recursive ? "-r":"", scp->location);
  else
    snprintf(execbuffer,sizeof(execbuffer),"scp -f %s %s",
    		scp->recursive ? "-r":"", scp->location);
  if(ssh_channel_request_exec(scp->channel,execbuffer) == SSH_ERROR){
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  if(scp->mode == SSH_SCP_WRITE){
	  r=ssh_channel_read(scp->channel,&code,1,0);
	  if(r<=0){
	    ssh_set_error(scp->session,SSH_FATAL, "Error reading status code: %s",ssh_get_error(scp->session));
	    scp->state=SSH_SCP_ERROR;
	    return SSH_ERROR;
	  }
	  if(code != 0){
		  ssh_set_error(scp->session,SSH_FATAL, "scp status code %ud not valid", code);
		  scp->state=SSH_SCP_ERROR;
		  return SSH_ERROR;
	  }
  } else {
	  ssh_channel_write(scp->channel,"",1);
  }
  if(scp->mode == SSH_SCP_WRITE)
    scp->state=SSH_SCP_WRITE_INITED;
  else
    scp->state=SSH_SCP_READ_INITED;
  return SSH_OK;
}

/**
 * @brief Close the scp channel.
 *
 * @param[in]  scp      The scp context to close.
 *
 * @return SSH_OK on success or an SSH error code.
 *
 * @see ssh_scp_init()
 */
int ssh_scp_close(ssh_scp scp)
{
  char buffer[128];
  int err;
  if(scp==NULL)
    return SSH_ERROR;
  if(scp->channel != NULL){
    if(ssh_channel_send_eof(scp->channel) == SSH_ERROR){
      scp->state=SSH_SCP_ERROR;
      return SSH_ERROR;
    }
    /* avoid situations where data are buffered and
     * not yet stored on disk. This can happen if the close is sent
     * before we got the EOF back
     */
    while(!ssh_channel_is_eof(scp->channel)){
      err=ssh_channel_read(scp->channel,buffer,sizeof(buffer),0);
      if(err==SSH_ERROR || err==0)
        break;
    }
    if(ssh_channel_close(scp->channel) == SSH_ERROR){
      scp->state=SSH_SCP_ERROR;
      return SSH_ERROR;
    }
    ssh_channel_free(scp->channel);
    scp->channel=NULL;
  }
  scp->state=SSH_SCP_NEW;
  return SSH_OK;
}

/**
 * @brief Free a scp context.
 *
 * @param[in]  scp      The context to free.
 *
 * @see ssh_scp_new()
 */
void ssh_scp_free(ssh_scp scp)
{
  if(scp==NULL)
      return;
  if(scp->state != SSH_SCP_NEW)
    ssh_scp_close(scp);
  if(scp->channel)
    ssh_channel_free(scp->channel);
  SAFE_FREE(scp->location);
  SAFE_FREE(scp->request_name);
  SAFE_FREE(scp->warning);
  SAFE_FREE(scp);
}

/**
 * @brief Create a directory in a scp in sink mode.
 *
 * @param[in]  scp      The scp handle.
 *
 * @param[in]  dirname  The name of the directory being created.
 *
 * @param[in]  mode     The UNIX permissions for the new directory, e.g. 0755.
 *
 * @returns             SSH_OK if the directory has been created, SSH_ERROR if
 *                      an error occured.
 *
 * @see ssh_scp_leave_directory()
 */
int ssh_scp_push_directory(ssh_scp scp, const char *dirname, int mode){
  char buffer[1024];
  int r;
  uint8_t code;
  char *dir;
  char *perms;
  if(scp==NULL)
      return SSH_ERROR;
  if(scp->state != SSH_SCP_WRITE_INITED){
    ssh_set_error(scp->session,SSH_FATAL,"ssh_scp_push_directory called under invalid state");
    return SSH_ERROR;
  }
  dir=ssh_basename(dirname);
  perms=ssh_scp_string_mode(mode);
  snprintf(buffer, sizeof(buffer), "D%s 0 %s\n", perms, dir);
  SAFE_FREE(dir);
  SAFE_FREE(perms);
  r=ssh_channel_write(scp->channel,buffer,strlen(buffer));
  if(r==SSH_ERROR){
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  r=ssh_channel_read(scp->channel,&code,1,0);
  if(r<=0){
    ssh_set_error(scp->session,SSH_FATAL, "Error reading status code: %s",ssh_get_error(scp->session));
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  if(code != 0){
    ssh_set_error(scp->session,SSH_FATAL, "scp status code %ud not valid", code);
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  return SSH_OK;
}

/**
 * @brief Leave a directory.
 *
 * @returns             SSH_OK if the directory has been left,SSH_ERROR if an
 *                      error occured.
 *
 * @see ssh_scp_push_directory()
 */
 int ssh_scp_leave_directory(ssh_scp scp){
  char buffer[]="E\n";
  int r;
  uint8_t code;
  if(scp==NULL)
      return SSH_ERROR;
  if(scp->state != SSH_SCP_WRITE_INITED){
    ssh_set_error(scp->session,SSH_FATAL,"ssh_scp_leave_directory called under invalid state");
    return SSH_ERROR;
  }
  r=ssh_channel_write(scp->channel,buffer,strlen(buffer));
  if(r==SSH_ERROR){
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  r=ssh_channel_read(scp->channel,&code,1,0);
  if(r<=0){
    ssh_set_error(scp->session,SSH_FATAL, "Error reading status code: %s",ssh_get_error(scp->session));
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  if(code != 0){
    ssh_set_error(scp->session,SSH_FATAL, "scp status code %ud not valid", code);
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  return SSH_OK;
}

/**
 * @brief Initialize the sending of a file to a scp in sink mode, using a 64-bit size.
 *
 * @param[in]  scp      The scp handle.
 *
 * @param[in]  filename The name of the file being sent. It should not contain
 *                      any path indicator
 *
 * @param[in]  size     Exact size in bytes of the file being sent.
 *
 * @param[in]  mode     The UNIX permissions for the new file, e.g. 0644.
 *
 * @returns             SSH_OK if the file is ready to be sent, SSH_ERROR if an
 *                      error occured.
 *
 * @see ssh_scp_push_file()
 */
int ssh_scp_push_file64(ssh_scp scp, const char *filename, uint64_t size, int mode){
  char buffer[1024];
  int r;
  uint8_t code;
  char *file;
  char *perms;
  if(scp==NULL)
      return SSH_ERROR;
  if(scp->state != SSH_SCP_WRITE_INITED){
    ssh_set_error(scp->session,SSH_FATAL,"ssh_scp_push_file called under invalid state");
    return SSH_ERROR;
  }
  file=ssh_basename(filename);
  perms=ssh_scp_string_mode(mode);
  SSH_LOG(SSH_LOG_PROTOCOL,"SCP pushing file %s, size %" PRIu64 " with permissions '%s'",file,size,perms);
  snprintf(buffer, sizeof(buffer), "C%s %" PRIu64 " %s\n", perms, size, file);
  SAFE_FREE(file);
  SAFE_FREE(perms);
  r=ssh_channel_write(scp->channel,buffer,strlen(buffer));
  if(r==SSH_ERROR){
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  r=ssh_channel_read(scp->channel,&code,1,0);
  if(r<=0){
    ssh_set_error(scp->session,SSH_FATAL, "Error reading status code: %s",ssh_get_error(scp->session));
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  if(code != 0){
    ssh_set_error(scp->session,SSH_FATAL, "scp status code %ud not valid", code);
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  scp->filelen = size;
  scp->processed = 0;
  scp->state=SSH_SCP_WRITE_WRITING;
  return SSH_OK;
}

/**
 * @brief Initialize the sending of a file to a scp in sink mode.
 *
 * @param[in]  scp      The scp handle.
 *
 * @param[in]  filename The name of the file being sent. It should not contain
 *                      any path indicator
 *
 * @param[in]  size     Exact size in bytes of the file being sent.
 *
 * @param[in]  mode     The UNIX permissions for the new file, e.g. 0644.
 *
 * @returns             SSH_OK if the file is ready to be sent, SSH_ERROR if an
 *                      error occured.
 */
int ssh_scp_push_file(ssh_scp scp, const char *filename, size_t size, int mode){
	return ssh_scp_push_file64(scp, filename, (uint64_t) size, mode);
}

/**
 * @internal
 *
 * @brief Wait for a response of the scp server.
 *
 * @param[in]  scp      The scp handle.
 *
 * @param[out] response A pointer where the response message must be copied if
 *                      any. This pointer must then be free'd.
 *
 * @returns             The return code, SSH_ERROR a error occured.
 */
int ssh_scp_response(ssh_scp scp, char **response){
	unsigned char code;
	int r;
	char msg[128];
	if(scp==NULL)
	    return SSH_ERROR;
	r=ssh_channel_read(scp->channel,&code,1,0);
	if(r == SSH_ERROR)
		return SSH_ERROR;
	if(code == 0)
		return 0;
	if(code > 2){
		ssh_set_error(scp->session,SSH_FATAL, "SCP: invalid status code %ud received", code);
		scp->state=SSH_SCP_ERROR;
		return SSH_ERROR;
	}
	r=ssh_scp_read_string(scp,msg,sizeof(msg));
	if(r==SSH_ERROR)
		return r;
	/* Warning */
	if(code == 1){
		ssh_set_error(scp->session,SSH_REQUEST_DENIED, "SCP: Warning: status code 1 received: %s", msg);
		SSH_LOG(SSH_LOG_RARE,"SCP: Warning: status code 1 received: %s", msg);
		if(response)
			*response=strdup(msg);
		return 1;
	}
	if(code == 2){
		ssh_set_error(scp->session,SSH_FATAL, "SCP: Error: status code 2 received: %s", msg);
		if(response)
			*response=strdup(msg);
		return 2;
	}
	/* Not reached */
	return SSH_ERROR;
}

/**
 * @brief Write into a remote scp file.
 *
 * @param[in]  scp      The scp handle.
 *
 * @param[in]  buffer   The buffer to write.
 *
 * @param[in]  len      The number of bytes to write.
 *
 * @returns             SSH_OK if the write was successful, SSH_ERROR an error
 *                      occured while writing.
 */
int ssh_scp_write(ssh_scp scp, const void *buffer, size_t len){
  int w;
  int r;
  uint8_t code;
  if(scp==NULL)
      return SSH_ERROR;
  if(scp->state != SSH_SCP_WRITE_WRITING){
    ssh_set_error(scp->session,SSH_FATAL,"ssh_scp_write called under invalid state");
    return SSH_ERROR;
  }
  if(scp->processed + len > scp->filelen)
    len = (size_t) (scp->filelen - scp->processed);
  /* hack to avoid waiting for window change */
  r = ssh_channel_poll(scp->channel, 0);
  if (r == SSH_ERROR) {
      scp->state = SSH_SCP_ERROR;
      return SSH_ERROR;
  }
  w=ssh_channel_write(scp->channel,buffer,len);
  if(w != SSH_ERROR)
    scp->processed += w;
  else {
    scp->state=SSH_SCP_ERROR;
    //return=channel_get_exit_status(scp->channel);
    return SSH_ERROR;
  }
  /* Far end sometimes send a status message, which we need to read
   * and handle */
  r = ssh_channel_poll(scp->channel,0);
  if(r > 0){
    r = ssh_channel_read(scp->channel, &code, 1, 0);
    if(r == SSH_ERROR){
      return SSH_ERROR;
    }
    if(code == 1 || code == 2){
      ssh_set_error(scp->session,SSH_REQUEST_DENIED, "SCP: Error: status code %i received", code);
      return SSH_ERROR;
    }
  }
  /* Check if we arrived at end of file */
  if(scp->processed == scp->filelen) {
    code = 0;
    w = ssh_channel_write(scp->channel, &code, 1);
    if(w == SSH_ERROR){
      scp->state = SSH_SCP_ERROR;
      return SSH_ERROR;
    }
    scp->processed=scp->filelen=0;
    scp->state=SSH_SCP_WRITE_INITED;
  }
  return SSH_OK;
}

/**
 * @brief Read a string on a channel, terminated by '\n'
 *
 * @param[in]  scp      The scp handle.
 *
 * @param[out] buffer   A pointer to a buffer to place the string.
 *
 * @param[in]  len      The size of the buffer in bytes. If the string is bigger
 *                      than len-1, only len-1 bytes are read and the string is
 *                      null-terminated.
 *
 * @returns             SSH_OK if the string was read, SSH_ERROR if an error
 *                      occured while reading.
 */
int ssh_scp_read_string(ssh_scp scp, char *buffer, size_t len){
  size_t r=0;
  int err=SSH_OK;
  if(scp==NULL)
      return SSH_ERROR;
  while(r<len-1){
    err=ssh_channel_read(scp->channel,&buffer[r],1,0);
    if(err==SSH_ERROR){
      break;
    }
    if(err==0){
      ssh_set_error(scp->session,SSH_FATAL,"End of file while reading string");
      err=SSH_ERROR;
      break;
    }
    r++;
    if(buffer[r-1] == '\n')
      break;
  }
  buffer[r]=0;
  return err;
}

/**
 * @brief Wait for a scp request (file, directory).
 *
 * @returns             SSH_SCP_REQUEST_NEWFILE:       The other side is sending
 *                                                     a file
 *                      SSH_SCP_REQUEST_NEWDIR:  The other side is sending
 *                                                     a directory
 *                      SSH_SCP_REQUEST_ENDDIR: The other side has
 *                                                     finished with the current
 *                                                     directory
 *                      SSH_SCP_REQUEST_WARNING: The other side sent us a warning
 *                      SSH_SCP_REQUEST_EOF: The other side finished sending us
 *                                           files and data.
 *                      SSH_ERROR:                     Some error happened
 *
 * @see ssh_scp_read()
 * @see ssh_scp_deny_request()
 * @see ssh_scp_accept_request()
 * @see ssh_scp_request_get_warning()
 */
int ssh_scp_pull_request(ssh_scp scp){
  char buffer[MAX_BUF_SIZE] = {0};
  char *mode=NULL;
  char *p,*tmp;
  uint64_t size;
  char *name=NULL;
  int err;
  if(scp==NULL)
      return SSH_ERROR;
  if(scp->state != SSH_SCP_READ_INITED){
    ssh_set_error(scp->session,SSH_FATAL,"ssh_scp_pull_request called under invalid state");
    return SSH_ERROR;
  }
  err=ssh_scp_read_string(scp,buffer,sizeof(buffer));
  if(err==SSH_ERROR){
	if(ssh_channel_is_eof(scp->channel)){
		scp->state=SSH_SCP_TERMINATED;
		return SSH_SCP_REQUEST_EOF;
	}
    return err;
  }
  p=strchr(buffer,'\n');
  if(p!=NULL)
	  *p='\0';
  SSH_LOG(SSH_LOG_PROTOCOL,"Received SCP request: '%s'",buffer);
  switch(buffer[0]){
    case 'C':
      /* File */
    case 'D':
      /* Directory */
      p=strchr(buffer,' ');
      if(p==NULL)
        goto error;
      *p='\0';
      p++;
      //mode=strdup(&buffer[1]);
      scp->request_mode=ssh_scp_integer_mode(&buffer[1]);
      tmp=p;
      p=strchr(p,' ');
      if(p==NULL)
        goto error;
      *p=0;
      size = strtoull(tmp,NULL,10);
      p++;
      name=strdup(p);
      SAFE_FREE(scp->request_name);
      scp->request_name=name;
      if(buffer[0]=='C'){
        scp->filelen=size;
        scp->request_type=SSH_SCP_REQUEST_NEWFILE;
      } else {
        scp->filelen='0';
        scp->request_type=SSH_SCP_REQUEST_NEWDIR;
      }
      scp->state=SSH_SCP_READ_REQUESTED;
      scp->processed = 0;
      return scp->request_type;
      break;
    case 'E':
    	scp->request_type=SSH_SCP_REQUEST_ENDDIR;
    	ssh_channel_write(scp->channel,"",1);
    	return scp->request_type;
    case 0x1:
    	ssh_set_error(scp->session,SSH_REQUEST_DENIED,"SCP: Warning: %s",&buffer[1]);
    	scp->request_type=SSH_SCP_REQUEST_WARNING;
    	SAFE_FREE(scp->warning);
    	scp->warning=strdup(&buffer[1]);
    	return scp->request_type;
    case 0x2:
    	ssh_set_error(scp->session,SSH_FATAL,"SCP: Error: %s",&buffer[1]);
    	return SSH_ERROR;
    case 'T':
      /* Timestamp */
    default:
      ssh_set_error(scp->session,SSH_FATAL,"Unhandled message: (%d)%s",buffer[0],buffer);
      return SSH_ERROR;
  }

  /* a parsing error occured */
  error:
  SAFE_FREE(name);
  SAFE_FREE(mode);
  ssh_set_error(scp->session,SSH_FATAL,"Parsing error while parsing message: %s",buffer);
  return SSH_ERROR;
}

/**
 * @brief Deny the transfer of a file or creation of a directory coming from the
 * remote party.
 *
 * @param[in]  scp      The scp handle.
 * @param[in]  reason   A nul-terminated string with a human-readable
 *                      explanation of the deny.
 *
 * @returns             SSH_OK if the message was sent, SSH_ERROR if the sending
 *                      the message failed, or sending it in a bad state.
 */
int ssh_scp_deny_request(ssh_scp scp, const char *reason){
  char buffer[MAX_BUF_SIZE];
  int err;
  if(scp==NULL)
      return SSH_ERROR;
  if(scp->state != SSH_SCP_READ_REQUESTED){
    ssh_set_error(scp->session,SSH_FATAL,"ssh_scp_deny_request called under invalid state");
    return SSH_ERROR;
  }
  snprintf(buffer,sizeof(buffer),"%c%s\n",2,reason);
  err=ssh_channel_write(scp->channel,buffer,strlen(buffer));
  if(err==SSH_ERROR) {
    return SSH_ERROR;
  }
  else {
    scp->state=SSH_SCP_READ_INITED;
    return SSH_OK;
  }
}

/**
 * @brief Accepts transfer of a file or creation of a directory coming from the
 * remote party.
 *
 * @param[in]  scp      The scp handle.
 *
 * @returns             SSH_OK if the message was sent, SSH_ERROR if sending the
 *                      message failed, or sending it in a bad state.
 */
int ssh_scp_accept_request(ssh_scp scp){
  char buffer[]={0x00};
  int err;
  if(scp==NULL)
      return SSH_ERROR;
  if(scp->state != SSH_SCP_READ_REQUESTED){
    ssh_set_error(scp->session,SSH_FATAL,"ssh_scp_deny_request called under invalid state");
    return SSH_ERROR;
  }
  err=ssh_channel_write(scp->channel,buffer,1);
  if(err==SSH_ERROR) {
    return SSH_ERROR;
  }
  if(scp->request_type==SSH_SCP_REQUEST_NEWFILE)
    scp->state=SSH_SCP_READ_READING;
  else
    scp->state=SSH_SCP_READ_INITED;
  return SSH_OK;
}

/** @brief Read from a remote scp file
 * @param[in]  scp      The scp handle.
 *
 * @param[in]  buffer   The destination buffer.
 *
 * @param[in]  size     The size of the buffer.
 *
 * @returns             The nNumber of bytes read, SSH_ERROR if an error occured
 *                      while reading.
 */
int ssh_scp_read(ssh_scp scp, void *buffer, size_t size){
  int r;
  int code;
  if(scp==NULL)
      return SSH_ERROR;
  if(scp->state == SSH_SCP_READ_REQUESTED && scp->request_type == SSH_SCP_REQUEST_NEWFILE){
    r=ssh_scp_accept_request(scp);
    if(r==SSH_ERROR)
      return r;
  }
  if(scp->state != SSH_SCP_READ_READING){
    ssh_set_error(scp->session,SSH_FATAL,"ssh_scp_read called under invalid state");
    return SSH_ERROR;
  }
  if(scp->processed + size > scp->filelen)
    size = (size_t) (scp->filelen - scp->processed);
  if(size > 65536)
    size=65536; /* avoid too large reads */
  r=ssh_channel_read(scp->channel,buffer,size,0);
  if(r != SSH_ERROR)
    scp->processed += r;
  else {
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  /* Check if we arrived at end of file */
  if(scp->processed == scp->filelen) {
    scp->processed=scp->filelen=0;
    ssh_channel_write(scp->channel,"",1);
    code=ssh_scp_response(scp,NULL);
    if(code == 0){
    	scp->state=SSH_SCP_READ_INITED;
    	return r;
    }
    if(code==1){
    	scp->state=SSH_SCP_READ_INITED;
    	return SSH_ERROR;
    }
    scp->state=SSH_SCP_ERROR;
    return SSH_ERROR;
  }
  return r;
}

/**
 * @brief Get the name of the directory or file being pushed from the other
 * party.
 *
 * @returns             The file name, NULL on error. The string should not be
 *                      freed.
 */
const char *ssh_scp_request_get_filename(ssh_scp scp){
  if(scp==NULL)
      return NULL;
  return scp->request_name;
}

/**
 * @brief Get the permissions of the directory or file being pushed from the
 * other party.
 *
 * @returns             The UNIX permission, e.g 0644, -1 on error.
 */
int ssh_scp_request_get_permissions(ssh_scp scp){
  if(scp==NULL)
      return -1;
  return scp->request_mode;
}

/** @brief Get the size of the file being pushed from the other party.
 *
 * @returns             The numeric size of the file being read.
 * @warning             The real size may not fit in a 32 bits field and may
 *                      be truncated.
 * @see ssh_scp_request_get_size64()
 */
size_t ssh_scp_request_get_size(ssh_scp scp){
  if(scp==NULL)
      return 0;
  return (size_t)scp->filelen;
}

/** @brief Get the size of the file being pushed from the other party.
 *
 * @returns             The numeric size of the file being read.
 */
uint64_t ssh_scp_request_get_size64(ssh_scp scp){
  if(scp==NULL)
      return 0;
  return scp->filelen;
}

/**
 * @brief Convert a scp text mode to an integer.
 *
 * @param[in]  mode     The mode to convert, e.g. "0644".
 *
 * @returns             An integer value, e.g. 420 for "0644".
 */
int ssh_scp_integer_mode(const char *mode){
	int value=strtoul(mode,NULL,8) & 0xffff;
	return value;
}

/**
 * @brief Convert a unix mode into a scp string.
 *
 * @param[in]  mode     The mode to convert, e.g. 420 or 0644.
 *
 * @returns             A pointer to a malloc'ed string containing the scp mode,
 *                      e.g. "0644".
 */
char *ssh_scp_string_mode(int mode){
	char buffer[16];
	snprintf(buffer,sizeof(buffer),"%.4o",mode);
	return strdup(buffer);
}

/**
 * @brief Get the warning string from a scp handle.
 *
 * @param[in]  scp      The scp handle.
 *
 * @returns             A warning string, or NULL on error. The string should
 *                      not be freed.
 */
const char *ssh_scp_request_get_warning(ssh_scp scp){
  if(scp==NULL)
      return NULL;
	return scp->warning;
}

/** @} */