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-rw-r--r--include/libssh/sftp.h1
-rw-r--r--libssh/sftp.c108
2 files changed, 108 insertions, 1 deletions
diff --git a/include/libssh/sftp.h b/include/libssh/sftp.h
index c5e7066f..4d49a4d2 100644
--- a/include/libssh/sftp.h
+++ b/include/libssh/sftp.h
@@ -146,6 +146,7 @@ int sftp_file_close(SFTP_FILE *file);
/* access are the sames than the ones from ansi fopen() */
SFTP_FILE *sftp_open(SFTP_SESSION *session, char *file, int access, SFTP_ATTRIBUTES *attr);
int sftp_read(SFTP_FILE *file, void *dest, int len);
+int sftp_async_read(SFTP_FILE *file, void *data, int len, int *id);
int sftp_write(SFTP_FILE *file, void *source, int len);
void sftp_seek(SFTP_FILE *file, int new_offset);
unsigned long sftp_tell(SFTP_FILE *file);
diff --git a/libssh/sftp.c b/libssh/sftp.c
index 7299be41..438938a7 100644
--- a/libssh/sftp.c
+++ b/libssh/sftp.c
@@ -21,6 +21,11 @@ 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. */
+/** \defgroup ssh_sftp SFTP functions
+ * \brief SFTP handling functions
+ */
+/** \addtogroup ssh_sftp
+ * @{ */
#include <stdlib.h>
#include <string.h>
@@ -935,6 +940,106 @@ int sftp_read(SFTP_FILE *handle, void *data, int len){
return -1; /* not reached */
}
+/** This function does an asynchronous read on a file. Its goal is to avoid the slowdowns related to
+ * the request/response pattern of a synchronous read.
+ * To use if, you must call the function two times.
+ * The first time, *id must be a pointer to an integer containing 0. The function will always return SSH_AGAIN the first time.
+ * The second time, the function will block until the data have been read, and will return the number of bytes read.
+ * If the file is opened in non-blocking mode, the second-time reading will return SSH_AGAIN until the data are available.
+ * \brief Asynchronous read on a file
+ * \param file the file handle
+ * \param data pointer to the data to be written
+ * \param len length of data to be read
+ * \param id a pointer to an identifier
+ * \return 0 When the file is EOF
+ * SSH_AGAIN the function has to be called again
+ * SSH_ERROR in case of error
+ * otherwise, the number of bytes read is returned
+ * \warning when calling the function for the first time, the internal offset is updated
+ * corresponding to the len parameter. If the length effectively read is different from the
+ * len parameter, every following read() will be out of sync.
+ * */
+int sftp_async_read(SFTP_FILE *file, void *data, int len, int *id){
+ SFTP_MESSAGE *msg=NULL;
+ STATUS_MESSAGE *status;
+ SFTP_SESSION *sftp=file->sftp;
+ STRING *datastring;
+ int err=0;
+ BUFFER *buffer;
+ if(id==NULL){
+ ssh_set_error(sftp->session,SSH_REQUEST_DENIED,"id parameter must not be null");
+ return -1;
+ }
+ if(file->eof)
+ return 0;
+ if(*id==0){
+ // launch a new request
+ buffer=buffer_new();
+ *id=sftp_get_new_id(sftp);
+ buffer_add_u32(buffer,*id);
+ buffer_add_ssh_string(buffer,file->handle);
+ buffer_add_u64(buffer,htonll(file->offset));
+ buffer_add_u32(buffer,htonl(len));
+ sftp_packet_write(sftp,SSH_FXP_READ,buffer);
+ buffer_free(buffer);
+ file->offset += len; // assume we'll read len bytes
+ return SSH_AGAIN; // must call back
+ } else {
+ // handle an existing request
+ while(!msg){
+ if (file->nonblocking){
+ if(channel_poll(sftp->channel,0)==0){
+ /* we cannot block */
+ return SSH_AGAIN;
+ }
+ }
+ if(sftp_read_and_dispatch(sftp))
+ /* something nasty has happened */
+ return -1;
+ msg=sftp_dequeue(sftp,*id);
+ }
+ *id=0;
+ switch (msg->packet_type){
+ case SSH_FXP_STATUS:
+ status=parse_status_msg(msg);
+ sftp_message_free(msg);
+ if(!status)
+ return -1;
+ if(status->status != SSH_FX_EOF){
+ ssh_set_error(sftp->session,SSH_REQUEST_DENIED,"sftp server : %s",status->errormsg);
+ err=-1;
+ } else
+ file->eof=1;
+ status_msg_free(status);
+ return err?err:0;
+ case SSH_FXP_DATA:
+ datastring=buffer_get_ssh_string(msg->payload);
+ sftp_message_free(msg);
+ if(!datastring){
+ ssh_set_error(sftp->session,SSH_FATAL,"Received invalid DATA packet from sftp server");
+ return -1;
+ }
+ if(string_len(datastring)>len){
+ ssh_set_error(sftp->session,SSH_FATAL,"Received a too big DATA packet from sftp server : %d and asked for %d",
+ string_len(datastring),len);
+ free(datastring);
+ return -1;
+ }
+ len=string_len(datastring);
+ //handle->offset+=len;
+ /* We already have set the offset previously. All we can do is warn that the expected len
+ * and effective lengths are different */
+ memcpy(data,datastring->string,len);
+ free(datastring);
+ return len;
+ default:
+ ssh_set_error(sftp->session,SSH_FATAL,"Received message %d during read!",msg->packet_type);
+ sftp_message_free(msg);
+ return -1;
+ }
+ }
+
+}
int sftp_write(SFTP_FILE *file, void *data, int len){
SFTP_MESSAGE *msg=NULL;
STATUS_MESSAGE *status;
@@ -1328,5 +1433,6 @@ SFTP_ATTRIBUTES *sftp_fstat(SFTP_FILE *file) {
return NULL;
}
-
#endif /* NO_SFTP */
+
+/** @} */