Make _libssh2_sftp_read() fully non-blocking safe. This makes
libssh2_sftp_readnb() non-blocking safe and libssh2_sftp_read() blocking safe
Этот коммит содержится в:
James Housley
родитель
75ac861c7a
Коммит
42f0f69a35
311
src/sftp.c
311
src/sftp.c
@ -74,6 +74,13 @@
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#define SSH_FXP_EXTENDED 200
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#define SSH_FXP_EXTENDED_REPLY 201
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typedef enum {
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sftp_read_idle = 0,
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sftp_read_packet_allocated,
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sftp_read_packet_created,
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sftp_read_packet_sent
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} libssh2_sftp_read_state;
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typedef enum {
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sftp_readdir_idle = 0,
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sftp_readdir_packet_created,
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@ -98,11 +105,17 @@ struct _LIBSSH2_SFTP {
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/* Time that libssh2_sftp_packet_requirev() started reading */
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time_t requirev_start;
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/* State variables used in _libssh2_sftp_read() */
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libssh2_sftp_read_state read_state;
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unsigned char *read_packet;
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unsigned long read_request_id;
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size_t read_total_read;
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/* State variables used in _libssh2_sftp_readdir() */
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libssh2_sftp_readdir_state readdir_state;
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unsigned char *readdir_packet;
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unsigned long readdir_request_id;
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libssh2_sftp_readdir_state readdir_state;
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unsigned char *readdir_packet;
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unsigned long readdir_request_id;
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};
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#define LIBSSH2_SFTP_HANDLE_FILE 0
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@ -379,7 +392,9 @@ static int libssh2_sftp_packet_requirev(LIBSSH2_SFTP *sftp, int num_valid_respon
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sftp->requirev_start = time(NULL);
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/* Flush */
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int bl = libssh2_channel_get_blocking(sftp->channel);
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while (libssh2_sftp_packet_read(sftp, 0, 1) > 0);
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libssh2_channel_set_blocking(sftp->channel, bl);
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}
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bl = libssh2_channel_get_blocking(sftp->channel);
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@ -776,113 +791,161 @@ LIBSSH2_API LIBSSH2_SFTP_HANDLE *libssh2_sftp_open_ex(LIBSSH2_SFTP *sftp, const
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/* {{{ _libssh2_sftp_read
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* Read from an SFTP file handle blocking/non-blocking depending on state
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*/
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/* _libssh2_sftp_read - NB-UNSAFE?? */
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static ssize_t _libssh2_sftp_read(LIBSSH2_SFTP_HANDLE *handle,
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char *buffer, size_t buffer_maxlen)
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/* _libssh2_sftp_read - NB-SAFE */
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static ssize_t _libssh2_sftp_read(LIBSSH2_SFTP_HANDLE *handle, char *buffer,
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size_t buffer_maxlen)
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{
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LIBSSH2_SFTP *sftp = handle->sftp;
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LIBSSH2_CHANNEL *channel = sftp->channel;
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LIBSSH2_SESSION *session = channel->session;
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unsigned long data_len, request_id;
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ssize_t packet_len = handle->handle_len + 25; /* packet_len(4) + packet_type(1) + request_id(4) + handle_len(4) + offset(8) + length(4) */
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unsigned char *packet, *s, *data;
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static const unsigned char read_responses[2] = { SSH_FXP_DATA, SSH_FXP_STATUS };
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size_t bytes_read = 0;
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size_t bytes_requested = 0;
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size_t total_read = 0;
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int rc;
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LIBSSH2_SFTP *sftp = handle->sftp;
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LIBSSH2_CHANNEL *channel = sftp->channel;
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LIBSSH2_SESSION *session = channel->session;
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unsigned long data_len, request_id;
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/* 25 = packet_len(4) + packet_type(1) + request_id(4) + handle_len(4) + offset(8) + length(4) */
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ssize_t packet_len = handle->handle_len + 25;
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unsigned char *packet, *s, *data;
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static const unsigned char read_responses[2] = { SSH_FXP_DATA, SSH_FXP_STATUS };
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size_t bytes_read = 0;
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size_t bytes_requested = 0;
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size_t total_read = 0;
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int retcode;
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if (sftp->read_state == sftp_read_idle) {
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_libssh2_debug(session, LIBSSH2_DBG_SFTP, "Reading %lu bytes from SFTP handle", (unsigned long)buffer_maxlen);
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packet = LIBSSH2_ALLOC(session, packet_len);
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if (!packet) {
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libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate memory for FXP_CLOSE packet", 0);
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return -1;
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libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate memory for FXP_CLOSE packet", 0);
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return -1;
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}
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while (total_read < buffer_maxlen) {
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s = packet;
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/* If buffer_maxlen bytes will be requested, server may return
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* all with one packet. But libssh2 have packet length
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* limit. So we request data by pieces. */
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bytes_requested = buffer_maxlen - total_read;
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if (bytes_requested > LIBSSH2_SFTP_PACKET_MAXLEN-10) /* packet_type(1)+request_id(4)+data_length(4)+end_of_line_flag(1) */
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bytes_requested = LIBSSH2_SFTP_PACKET_MAXLEN-10;
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#ifdef LIBSSH2_DEBUG_SFTP
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_libssh2_debug(session, LIBSSH2_DBG_SFTP, "Requesting %lu bytes from SFTP handle", (unsigned long)bytes_requested);
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#endif
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libssh2_htonu32(s, packet_len - 4);
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s += 4;
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*(s++) = SSH_FXP_READ;
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request_id = sftp->request_id++;
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libssh2_htonu32(s, request_id);
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s += 4;
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libssh2_htonu32(s, handle->handle_len);
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s += 4;
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memcpy(s, handle->handle, handle->handle_len);
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s += handle->handle_len;
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libssh2_htonu64(s, handle->u.file.offset);
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s += 8;
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libssh2_htonu32(s, buffer_maxlen);
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s += 4;
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if (packet_len != libssh2_channel_write(channel, (char *)packet,
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packet_len)) {
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libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
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"Unable to send FXP_READ command", 0);
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LIBSSH2_FREE(session, packet);
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return -1;
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}
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/* #warning "XXX - Looping on PACKET_EAGAIN (blocking) until fix is migrated up farther" */
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while ((rc = libssh2_sftp_packet_requirev(sftp, 2, read_responses, request_id, &data, &data_len)) == PACKET_EAGAIN) {
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;
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}
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if (rc) {
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libssh2_error(session, LIBSSH2_ERROR_SOCKET_TIMEOUT,
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"Timeout waiting for status message", 0);
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return -1;
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}
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switch (data[0]) {
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case SSH_FXP_STATUS: {
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int retcode = libssh2_ntohu32(data + 5);
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LIBSSH2_FREE(session, packet);
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LIBSSH2_FREE(session, data);
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if (retcode == LIBSSH2_FX_EOF) {
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return total_read;
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} else {
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sftp->last_errno = retcode;
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libssh2_error(session, LIBSSH2_ERROR_SFTP_PROTOCOL, "SFTP Protocol Error", 0);
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return -1;
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}
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}
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case SSH_FXP_DATA:
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bytes_read = libssh2_ntohu32(data + 5);
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if (bytes_read > (data_len - 9)) {
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return -1;
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}
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#ifdef LIBSSH2_DEBUG_SFTP
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_libssh2_debug(session, LIBSSH2_DBG_SFTP,
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"%lu bytes returned",
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(unsigned long)bytes_read);
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#endif
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memcpy(buffer + total_read, data + 9, bytes_read);
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handle->u.file.offset += bytes_read;
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total_read += bytes_read;
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LIBSSH2_FREE(session, data);
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}
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sftp->read_state = sftp_read_packet_allocated;
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} else {
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packet = sftp->read_packet;
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request_id = sftp->read_request_id;
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total_read = sftp->read_total_read;
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}
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while (total_read < buffer_maxlen) {
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s = packet;
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/*
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* If buffer_maxlen bytes will be requested, server may return all
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* with one packet. But libssh2 have packet length limit.
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* So we request data by pieces.
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*/
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bytes_requested = buffer_maxlen - total_read;
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/* 10 = packet_type(1)+request_id(4)+data_length(4)+end_of_line_flag(1) */
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if (bytes_requested > LIBSSH2_SFTP_PACKET_MAXLEN - 10) {
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bytes_requested = LIBSSH2_SFTP_PACKET_MAXLEN - 10;
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}
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LIBSSH2_FREE(session, packet);
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return total_read;
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#ifdef LIBSSH2_DEBUG_SFTP
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_libssh2_debug(session, LIBSSH2_DBG_SFTP, "Requesting %lu bytes from SFTP handle", (unsigned long)bytes_requested);
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#endif
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if (sftp->read_state == sftp_read_packet_allocated) {
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libssh2_htonu32(s, packet_len - 4);
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s += 4;
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*(s++) = SSH_FXP_READ;
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request_id = sftp->request_id++;
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libssh2_htonu32(s, request_id);
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s += 4;
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libssh2_htonu32(s, handle->handle_len);
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s += 4;
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memcpy(s, handle->handle, handle->handle_len);
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s += handle->handle_len;
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libssh2_htonu64(s, handle->u.file.offset);
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s += 8;
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libssh2_htonu32(s, buffer_maxlen);
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s += 4;
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sftp->read_state = sftp_read_packet_created;
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}
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if (sftp->read_state != sftp_read_packet_sent) {
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if (libssh2_channel_get_blocking(channel)) {
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if (packet_len != libssh2_channel_write(channel, (char *)packet, packet_len)) {
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libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND, "Unable to send FXP_READ command", 0);
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LIBSSH2_FREE(session, packet);
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sftp->read_packet = NULL;
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sftp->read_state = sftp_read_idle;
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return -1;
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}
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} else {
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if ((retcode = libssh2_channel_writenb(channel, (char *)packet, packet_len)) == PACKET_EAGAIN) {
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sftp->read_packet = packet;
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sftp->read_request_id = request_id;
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sftp->read_total_read = total_read;
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return PACKET_EAGAIN;
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}
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else if (packet_len != retcode) {
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libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND, "Unable to send FXP_READ command", 0);
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LIBSSH2_FREE(session, packet);
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sftp->read_packet = NULL;
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sftp->read_state = sftp_read_idle;
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return -1;
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}
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}
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sftp->read_packet = packet;
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sftp->read_request_id = request_id;
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sftp->read_total_read = total_read;
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sftp->read_state = sftp_read_packet_sent;
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}
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retcode = libssh2_sftp_packet_requirev(sftp, 2, read_responses, request_id, &data, &data_len);
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if (retcode == PACKET_EAGAIN) {
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return PACKET_EAGAIN;
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}
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else if (retcode) {
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libssh2_error(session, LIBSSH2_ERROR_SOCKET_TIMEOUT, "Timeout waiting for status message", 0);
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LIBSSH2_FREE(session, packet);
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sftp->read_packet = NULL;
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sftp->read_state = sftp_read_idle;
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return -1;
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}
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switch (data[0]) {
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case SSH_FXP_STATUS:
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retcode = libssh2_ntohu32(data + 5);
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LIBSSH2_FREE(session, packet);
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LIBSSH2_FREE(session, data);
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sftp->read_packet = NULL;
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sftp->read_state = sftp_read_idle;
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if (retcode == LIBSSH2_FX_EOF) {
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return total_read;
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} else {
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sftp->last_errno = retcode;
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libssh2_error(session, LIBSSH2_ERROR_SFTP_PROTOCOL, "SFTP Protocol Error", 0);
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return -1;
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}
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case SSH_FXP_DATA:
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bytes_read = libssh2_ntohu32(data + 5);
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if (bytes_read > (data_len - 9)) {
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LIBSSH2_FREE(session, packet);
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sftp->read_packet = NULL;
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sftp->read_state = sftp_read_idle;
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return -1;
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}
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#ifdef LIBSSH2_DEBUG_SFTP
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_libssh2_debug(session, LIBSSH2_DBG_SFTP, "%lu bytes returned", (unsigned long)bytes_read);
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#endif
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memcpy(buffer + total_read, data + 9, bytes_read);
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handle->u.file.offset += bytes_read;
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total_read += bytes_read;
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LIBSSH2_FREE(session, data);
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/*
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* Set the state back to allocated, so a new one will be
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* created to either request more data or get EOF
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*/
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sftp->read_state = sftp_read_packet_allocated;
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}
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}
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LIBSSH2_FREE(session, packet);
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sftp->read_packet = NULL;
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sftp->read_state = sftp_read_idle;
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return total_read;
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}
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/* {{{ libssh2_sftp_read
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* Read from an SFTP file handle blocking
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@ -891,25 +954,25 @@ static ssize_t _libssh2_sftp_read(LIBSSH2_SFTP_HANDLE *handle,
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LIBSSH2_API ssize_t libssh2_sftp_read(LIBSSH2_SFTP_HANDLE *handle,
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char *buffer, size_t buffer_maxlen)
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{
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ssize_t rc;
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LIBSSH2_CHANNEL *ch = handle->sftp->channel;
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int bl = libssh2_channel_get_blocking(ch);
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/* set blocking */
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libssh2_channel_set_blocking(ch, 1);
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rc = _libssh2_sftp_read(handle, buffer, buffer_maxlen);
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/* restore state */
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libssh2_channel_set_blocking(ch, bl);
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if(rc < 0) {
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/* precent accidental returning of other return codes since
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this API does not support/provide those */
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return -1;
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}
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return rc;
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ssize_t rc;
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LIBSSH2_CHANNEL *ch = handle->sftp->channel;
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int bl = libssh2_channel_get_blocking(ch);
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/* set blocking */
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libssh2_channel_set_blocking(ch, 1);
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rc = _libssh2_sftp_read(handle, buffer, buffer_maxlen);
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/* restore state */
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libssh2_channel_set_blocking(ch, bl);
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if(rc < 0) {
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/* precent accidental returning of other return codes since
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this API does not support/provide those */
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return -1;
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}
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return rc;
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}
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/* }}} */
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