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libssh2_publickey_init: fixed to work better non-blocking

Browse Source 
This was triggered by a clang-analyzer complaint that turned out
to be valid, and it made me dig deeper and fix some generic non-
blocking problems I disovered in the code.

While cleaning this up, I moved session-specific stuff over to a
new session.h header from the libssh2_priv.h header.
This commit is contained in:
Daniel Stenberg
2010-04-24 20:21:22 +02:00
parent c5602fac58
commit 000b0f73d0
8 changed files with 164 additions and 98 deletions
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1
src/channel.c
View File

@@ -50,6 +50,7 @@
#include "channel.h"
#include "transport.h"
#include "packet.h"
#include "session.h"
/*
* _libssh2_channel_nextid

53
src/libssh2_priv.h
View File

@@ -857,6 +857,9 @@ struct _LIBSSH2_SESSION
LIBSSH2_CHANNEL *pkeyInit_channel;
unsigned char *pkeyInit_data;
size_t pkeyInit_data_len;
/* 19 = packet_len(4) + version_len(4) + "version"(7) + version_num(4) */
unsigned char pkeyInit_buffer[19];
size_t pkeyInit_buffer_sent; /* how much of buffer that has been sent */
/* State variables used in libssh2_packet_add() */
libssh2_nonblocking_states packAdd_state;
@@ -1107,8 +1110,6 @@ _libssh2_debug(LIBSSH2_SESSION * session, int context, const char *format, ...)
#define SSH_MSG_CHANNEL_SUCCESS 99
#define SSH_MSG_CHANNEL_FAILURE 100
void _libssh2_session_shutdown(LIBSSH2_SESSION * session);
#ifdef WIN32
ssize_t _libssh2_recv(libssh2_socket_t socket, void *buffer, size_t length, int flags);
ssize_t _libssh2_send(libssh2_socket_t socket, const void *buffer, size_t length, int flags);
@@ -1120,15 +1121,10 @@ ssize_t _libssh2_send(libssh2_socket_t socket, const void *buffer, size_t length
#define LIBSSH2_READ_TIMEOUT 60 /* generic timeout in seconds used when
waiting for more data to arrive */
int _libssh2_wait_socket(LIBSSH2_SESSION *session);
int libssh2_kex_exchange(LIBSSH2_SESSION * session, int reexchange,
key_exchange_state_t * state);
/* this is the lib-internal set blocking function */
int _libssh2_session_set_blocking(LIBSSH2_SESSION * session, int blocking);
/* Let crypt.c/hostkey.c expose their method structs */
const LIBSSH2_CRYPT_METHOD **libssh2_crypt_methods(void);
const LIBSSH2_HOSTKEY_METHOD **libssh2_hostkey_methods(void);
@@ -1148,49 +1144,6 @@ int _libssh2_pem_decode_integer(unsigned char **data, unsigned int *datalen,
/* global.c */
void _libssh2_init_if_needed (void);
/* Conveniance-macros to allow code like this;
int rc = BLOCK_ADJUST(rc, session, session_startup(session, sock) );
int rc = BLOCK_ADJUST_ERRNO(ptr, session, session_startup(session, sock) );
The point of course being to make sure that while in non-blocking mode
these always return no matter what the return code is, but in blocking mode
it blocks if EAGAIN is the reason for the return from the underlying
function.
*/
#define BLOCK_ADJUST(rc,sess,x) \
do { \
rc = x; \
/* the order of the check below is important to properly deal with the
case when the 'sess' is freed */ \
if((rc != LIBSSH2_ERROR_EAGAIN) || !sess->api_block_mode) \
break; \
rc = _libssh2_wait_socket(sess); \
if(rc) \
break; \
} while(1)
/*
* For functions that returns a pointer, we need to check if the API is
* non-blocking and return immediately. If the pointer is non-NULL we return
* immediately. If the API is blocking and we get a NULL we check the errno
* and *only* if that is EAGAIN we loop and wait for socket action.
*/
#define BLOCK_ADJUST_ERRNO(ptr,sess,x) \
do { \
int rc; \
ptr = x; \
if(!sess->api_block_mode || \
(ptr != NULL) || \
(libssh2_session_last_errno(sess) != LIBSSH2_ERROR_EAGAIN) ) \
break; \
rc = _libssh2_wait_socket(sess); \
if(rc) \
break; \
} while(1)
#define ARRAY_SIZE(a) (sizeof ((a)) / sizeof ((a)[0]))

107
src/publickey.c
View File

@@ -1,4 +1,5 @@
/* Copyright (c) 2004-2007, Sara Golemon <sarag@libssh2.org>
* Copyright (c) 2010 by Daniel Stenberg
* All rights reserved.
*
* Redistribution and use in source and binary forms,
@@ -38,6 +39,7 @@
#include "libssh2_priv.h"
#include "libssh2_publickey.h"
#include "channel.h"
#include "session.h"
#define LIBSSH2_PUBLICKEY_VERSION 2
@@ -215,7 +217,7 @@ publickey_response_id(unsigned char **pdata, size_t data_len)
return -1;
}
/* libssh2_publickey_response_success
/* publickey_response_success
*
* Generic helper routine to wait for success response and nothing else
*/
@@ -226,10 +228,9 @@ publickey_response_success(LIBSSH2_PUBLICKEY * pkey)
unsigned char *data, *s;
size_t data_len;
int response;
int rc;
while (1) {
rc = publickey_packet_receive(pkey, &data, &data_len);
int rc = publickey_packet_receive(pkey, &data, &data_len);
if (rc == LIBSSH2_ERROR_EAGAIN) {
return rc;
} else if (rc) {
@@ -239,11 +240,7 @@ publickey_response_success(LIBSSH2_PUBLICKEY * pkey)
}
s = data;
if ((response = publickey_response_id(&s, data_len)) < 0) {
LIBSSH2_FREE(session, data);
return _libssh2_error(session, LIBSSH2_ERROR_PUBLICKEY_PROTOCOL,
"Invalid publickey subsystem response code");
}
response = publickey_response_id(&s, data_len);
switch (response) {
case LIBSSH2_PUBLICKEY_RESPONSE_STATUS:
@@ -260,10 +257,14 @@ publickey_response_success(LIBSSH2_PUBLICKEY * pkey)
return -1;
}
default:
LIBSSH2_FREE(session, data);
if (response < 0) {
return _libssh2_error(session, LIBSSH2_ERROR_PUBLICKEY_PROTOCOL,
"Invalid publickey subsystem response code");
}
/* Unknown/Unexpected */
_libssh2_error(session, LIBSSH2_ERROR_PUBLICKEY_PROTOCOL,
"Unexpected publickey subsystem response, ignoring");
LIBSSH2_FREE(session, data);
data = NULL;
}
}
@@ -276,16 +277,12 @@ publickey_response_success(LIBSSH2_PUBLICKEY * pkey)
***************** */
/*
* libssh2_publickey_init
* publickey_init
*
* Startup the publickey subsystem
*/
LIBSSH2_API LIBSSH2_PUBLICKEY *
libssh2_publickey_init(LIBSSH2_SESSION * session)
static LIBSSH2_PUBLICKEY *publickey_init(LIBSSH2_SESSION *session)
{
/* 19 = packet_len(4) + version_len(4) + "version"(7) + version_num(4) */
unsigned char buffer[19];
unsigned char *s;
int response;
int rc;
@@ -301,37 +298,30 @@ libssh2_publickey_init(LIBSSH2_SESSION * session)
}
if (session->pkeyInit_state == libssh2_NB_state_allocated) {
do {
session->pkeyInit_channel =
libssh2_channel_open_ex(session, "session",
sizeof("session") - 1,
LIBSSH2_CHANNEL_WINDOW_DEFAULT,
LIBSSH2_CHANNEL_PACKET_DEFAULT, NULL,
0);
if (!session->pkeyInit_channel
&& (libssh2_session_last_errno(session) ==
LIBSSH2_ERROR_EAGAIN)) {
session->pkeyInit_channel =
_libssh2_channel_open(session, "session",
sizeof("session") - 1,
LIBSSH2_CHANNEL_WINDOW_DEFAULT,
LIBSSH2_CHANNEL_PACKET_DEFAULT, NULL,
0);
if (!session->pkeyInit_channel) {
if (libssh2_session_last_errno(session) == LIBSSH2_ERROR_EAGAIN)
/* The error state is already set, so leave it */
_libssh2_error(session, LIBSSH2_ERROR_EAGAIN,
"Would block to startup channel");
return NULL;
} else if (!session->pkeyInit_channel
&& (libssh2_session_last_errno(session) !=
LIBSSH2_ERROR_EAGAIN)) {
_libssh2_error(session, LIBSSH2_ERROR_CHANNEL_FAILURE,
"Unable to startup channel");
goto err_exit;
}
} while (!session->pkeyInit_channel);
_libssh2_error(session, LIBSSH2_ERROR_CHANNEL_FAILURE,
"Unable to startup channel");
goto err_exit;
}
session->pkeyInit_state = libssh2_NB_state_sent;
}
if (session->pkeyInit_state == libssh2_NB_state_sent) {
rc = libssh2_channel_process_startup(session->pkeyInit_channel,
"subsystem",
sizeof("subsystem") - 1,
"publickey", strlen("publickey"));
rc = _libssh2_channel_process_startup(session->pkeyInit_channel,
"subsystem",
sizeof("subsystem") - 1,
"publickey", strlen("publickey"));
if (rc == LIBSSH2_ERROR_EAGAIN) {
_libssh2_error(session, LIBSSH2_ERROR_EAGAIN,
"Would block starting publickey subsystem");
@@ -346,8 +336,9 @@ libssh2_publickey_init(LIBSSH2_SESSION * session)
}
if (session->pkeyInit_state == libssh2_NB_state_sent1) {
rc = libssh2_channel_handle_extended_data2(session->pkeyInit_channel,
LIBSSH2_CHANNEL_EXTENDED_DATA_IGNORE);
unsigned char *s;
rc = _libssh2_channel_extended_data(session->pkeyInit_channel,
LIBSSH2_CHANNEL_EXTENDED_DATA_IGNORE);
if (rc == LIBSSH2_ERROR_EAGAIN) {
_libssh2_error(session, LIBSSH2_ERROR_EAGAIN,
"Would block starting publickey subsystem");
@@ -365,7 +356,7 @@ libssh2_publickey_init(LIBSSH2_SESSION * session)
session->pkeyInit_pkey->channel = session->pkeyInit_channel;
session->pkeyInit_pkey->version = 0;
s = buffer;
s = session->pkeyInit_buffer;
_libssh2_htonu32(s, 4 + (sizeof("version") - 1) + 4);
s += 4;
_libssh2_htonu32(s, sizeof("version") - 1);
@@ -374,6 +365,7 @@ libssh2_publickey_init(LIBSSH2_SESSION * session)
s += sizeof("version") - 1;
_libssh2_htonu32(s, LIBSSH2_PUBLICKEY_VERSION);
s += 4;
session->pkeyInit_buffer_sent = 0;
_libssh2_debug(session, LIBSSH2_TRACE_PUBLICKEY,
"Sending publickey version packet advertising version %d support",
@@ -384,22 +376,30 @@ libssh2_publickey_init(LIBSSH2_SESSION * session)
if (session->pkeyInit_state == libssh2_NB_state_sent2) {
rc = _libssh2_channel_write(session->pkeyInit_channel, 0,
(char *) buffer, (s - buffer));
(char *)session->pkeyInit_buffer,
19 - session->pkeyInit_buffer_sent);
if (rc == LIBSSH2_ERROR_EAGAIN) {
_libssh2_error(session, LIBSSH2_ERROR_EAGAIN,
"Would block sending publickey version packet");
return NULL;
} else if ((s - buffer) != rc) {
_libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
} else if (rc) {
_libssh2_error(session, rc,
"Unable to send publickey version packet");
goto err_exit;
}
session->pkeyInit_buffer_sent += rc;
if(session->pkeyInit_buffer_sent < 19) {
_libssh2_error(session, LIBSSH2_ERROR_EAGAIN,
"Need to be called again to complete this");
return NULL;
}
session->pkeyInit_state = libssh2_NB_state_sent3;
}
if (session->pkeyInit_state == libssh2_NB_state_sent3) {
while (1) {
unsigned char *s;
rc = publickey_packet_receive(session->pkeyInit_pkey,
&session->pkeyInit_data,
&session->pkeyInit_data_len);
@@ -506,6 +506,23 @@ libssh2_publickey_init(LIBSSH2_SESSION * session)
return NULL;
}
/*
* libssh2_publickey_init
*
* Startup the publickey subsystem
*/
LIBSSH2_API LIBSSH2_PUBLICKEY *
libssh2_publickey_init(LIBSSH2_SESSION *session)
{
LIBSSH2_PUBLICKEY *ptr;
BLOCK_ADJUST_ERRNO(ptr, session,
publickey_init(session));
return ptr;
}
/*
* libssh2_publickey_add_ex
*

3
src/scp.c
View File

@@ -1,4 +1,4 @@
/* Copyright (c) 2009 by Daniel Stenberg
/* Copyright (c) 2009-2010 by Daniel Stenberg
* Copyright (c) 2004-2008, Sara Golemon <sarag@libssh2.org>
* All rights reserved.
*
@@ -41,6 +41,7 @@
#include <stdlib.h>
#include "channel.h"
#include "session.h"
/* Max. length of a quoted string after libssh2_shell_quotearg() processing */

5
src/session.c
View File

@@ -1,5 +1,5 @@
/* Copyright (c) 2004-2007 Sara Golemon <sarag@libssh2.org>
* Copyright (c) 2009 by Daniel Stenberg
* Copyright (c) 2009-2010 by Daniel Stenberg
* Copyright (c) 2010 Simon Josefsson <simon@josefsson.org>
* All rights reserved.
*
@@ -53,6 +53,7 @@
#endif
#include "transport.h"
#include "session.h"
/* libssh2_default_alloc
*/
@@ -520,8 +521,8 @@ libssh2_session_callback_set(LIBSSH2_SESSION * session,
int _libssh2_wait_socket(LIBSSH2_SESSION *session)
{
int rc;
int dir;
int seconds_to_next;
int dir;
rc = libssh2_keepalive_send (session, &seconds_to_next);
if (rc < 0)

91
src/session.h Normal file
View File

@@ -0,0 +1,91 @@
#ifndef LIBSSH2_SESSION_H
#define LIBSSH2_SESSION_H
/* Copyright (c) 2004-2007 Sara Golemon <sarag@libssh2.org>
* Copyright (c) 2009-2010 by Daniel Stenberg
* Copyright (c) 2010 Simon Josefsson <simon@josefsson.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms,
* with or without modification, are permitted provided
* that the following conditions are met:
*
* Redistributions of source code must retain the above
* copyright notice, this list of conditions and the
* following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* Neither the name of the copyright holder nor the names
* of any other contributors may be used to endorse or
* promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*/
/* Conveniance-macros to allow code like this;
int rc = BLOCK_ADJUST(rc, session, session_startup(session, sock) );
int rc = BLOCK_ADJUST_ERRNO(ptr, session, session_startup(session, sock) );
The point of course being to make sure that while in non-blocking mode
these always return no matter what the return code is, but in blocking mode
it blocks if EAGAIN is the reason for the return from the underlying
function.
*/
#define BLOCK_ADJUST(rc,sess,x) \
do { \
rc = x; \
/* the order of the check below is important to properly deal with the
case when the 'sess' is freed */ \
if((rc != LIBSSH2_ERROR_EAGAIN) || !sess->api_block_mode) \
break; \
rc = _libssh2_wait_socket(sess); \
if(rc) \
break; \
} while(1)
/*
* For functions that returns a pointer, we need to check if the API is
* non-blocking and return immediately. If the pointer is non-NULL we return
* immediately. If the API is blocking and we get a NULL we check the errno
* and *only* if that is EAGAIN we loop and wait for socket action.
*/
#define BLOCK_ADJUST_ERRNO(ptr,sess,x) \
do { \
int rc; \
ptr = x; \
if(!sess->api_block_mode || \
(ptr != NULL) || \
(libssh2_session_last_errno(sess) != LIBSSH2_ERROR_EAGAIN) ) \
break; \
rc = _libssh2_wait_socket(sess); \
if(rc) \
break; \
} while(1)
int _libssh2_wait_socket(LIBSSH2_SESSION *session);
/* this is the lib-internal set blocking function */
int _libssh2_session_set_blocking(LIBSSH2_SESSION * session, int blocking);
#endif /* LIBSSH2_SESSION_H */

1
src/sftp.c
View File

@@ -41,6 +41,7 @@
#include "libssh2_priv.h"
#include "libssh2_sftp.h"
#include "channel.h"
#include "session.h"
/* Note: Version 6 was documented at the time of writing
* However it was marked as "DO NOT IMPLEMENT" due to pending changes

1
src/userauth.c
View File

@@ -49,6 +49,7 @@
#endif
#include "transport.h"
#include "session.h"
/* libssh2_userauth_list
*