ClearML/dropbear
1
0
Fork 0
mirror of https://github.com/clearml/dropbear synced 2025-06-26 18:17:32 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Rearranged (and hopefully simplified) channel close/eof handling

Browse Source 
--HG--
branch : channel-fix
extra : convert_revision : d44aac5fec50b1d20515da77d410d3c511f16277
This commit is contained in:
Matt Johnston 2006-10-07 17:48:55 +00:00
parent df57eb3824
commit 786ea39ac4
2 changed files with 87 additions and 115 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

200
common-channel.c
View File

@ -43,17 +43,14 @@ static void send_msg_channel_open_confirmation(struct Channel* channel,
static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf); static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf);
static void send_msg_channel_window_adjust(struct Channel *channel, static void send_msg_channel_window_adjust(struct Channel *channel,
unsigned int incr); unsigned int incr);
static void send_msg_channel_data(struct Channel *channel, int isextended, static void send_msg_channel_data(struct Channel *channel, int isextended);
unsigned int exttype);
static void send_msg_channel_eof(struct Channel *channel); static void send_msg_channel_eof(struct Channel *channel);
static void send_msg_channel_close(struct Channel *channel); static void send_msg_channel_close(struct Channel *channel);
static void remove_channel(struct Channel *channel); static void remove_channel(struct Channel *channel);
static void delete_channel(struct Channel *channel); static void delete_channel(struct Channel *channel);
static void check_in_progress(struct Channel *channel); static void check_in_progress(struct Channel *channel);
static unsigned int write_pending(struct Channel * channel);
static void check_close(struct Channel *channel); static void check_close(struct Channel *channel);
static void close_write_fd(struct Channel * channel);
static void close_read_fd(struct Channel * channel, int fd);
static void close_chan_fd(struct Channel *channel, int fd, int how); static void close_chan_fd(struct Channel *channel, int fd, int how);
#define FD_UNINIT (-2) #define FD_UNINIT (-2)
@ -192,7 +189,7 @@ void channelio(fd_set *readfds, fd_set *writefds) {
struct Channel *channel; struct Channel *channel;
unsigned int i; unsigned int i;
/* iterate through all the possible channels */ /* foreach channel */
for (i = 0; i < ses.chansize; i++) { for (i = 0; i < ses.chansize; i++) {
channel = ses.channels[i]; channel = ses.channels[i];
@ -203,31 +200,19 @@ void channelio(fd_set *readfds, fd_set *writefds) {
/* read data and send it over the wire */ /* read data and send it over the wire */
if (channel->readfd >= 0 && FD_ISSET(channel->readfd, readfds)) { if (channel->readfd >= 0 && FD_ISSET(channel->readfd, readfds)) {
send_msg_channel_data(channel, 0, 0); send_msg_channel_data(channel, 0);
} }
/* read stderr data and send it over the wire */ /* read stderr data and send it over the wire */
if (channel->extrabuf == NULL && if (channel->extrabuf == NULL &&
channel->errfd >= 0 && FD_ISSET(channel->errfd, readfds)) { channel->errfd >= 0 && FD_ISSET(channel->errfd, readfds)) {
send_msg_channel_data(channel, 1, SSH_EXTENDED_DATA_STDERR); send_msg_channel_data(channel, 1);
} }
#if 0
/* XXX where is this required? */
if (channel->initconn) {
/* Handling for "in progress" connection - this is needed
* to avoid spinning 100% CPU when we connect to a server
* which doesn't send anything (tcpfwding) */
check_in_progress(channel);
continue; /* Important not to use the channel after
check_in_progress(), as it may be NULL */
}
#endif
/* write to program/pipe stdin */ /* write to program/pipe stdin */
if (channel->writefd >= 0 && FD_ISSET(channel->writefd, writefds)) { if (channel->writefd >= 0 && FD_ISSET(channel->writefd, writefds)) {
if (channel->initconn) { if (channel->initconn) {
/* XXX could this go somewhere cleaner? */ /* XXX should this go somewhere cleaner? */
check_in_progress(channel); check_in_progress(channel);
continue; /* Important not to use the channel after continue; /* Important not to use the channel after
check_in_progress(), as it may be NULL */ check_in_progress(), as it may be NULL */
@ -241,10 +226,10 @@ void channelio(fd_set *readfds, fd_set *writefds) {
writechannel(channel, channel->errfd, channel->extrabuf); writechannel(channel, channel->errfd, channel->extrabuf);
} }
/* now handle any of the channel-closing type stuff */ /* handle any channel closing etc */
check_close(channel); check_close(channel);
} /* foreach channel */ }
/* Listeners such as TCP, X11, agent-auth */ /* Listeners such as TCP, X11, agent-auth */
#ifdef USING_LISTENERS #ifdef USING_LISTENERS
@ -253,6 +238,20 @@ void channelio(fd_set *readfds, fd_set *writefds) {
} }
/* Returns true if there is data remaining to be written to stdin or
* stderr of a channel's endpoint. */
static unsigned int write_pending(struct Channel * channel) {
if (channel->writefd >= 0 && cbuf_getused(channel->writebuf) > 0) {
return 1;
} else if (channel->errfd >= 0 && channel->extrabuf &&
cbuf_getused(channel->writebuf) > 0) {
return 1;
}
return 0;
}
/* EOF/close handling */ /* EOF/close handling */
static void check_close(struct Channel *channel) { static void check_close(struct Channel *channel) {
@ -264,8 +263,13 @@ static void check_close(struct Channel *channel) {
channel->writebuf, channel->writebuf,
channel->writebuf ? 0 : cbuf_getused(channel->extrabuf))) channel->writebuf ? 0 : cbuf_getused(channel->extrabuf)))
/* XXX not good, doesn't flush out */ if (!channel->sent_close
if (channel->recv_close) { && channel->writefd == FD_CLOSED
&& (channel->errfd == FD_CLOSED || channel->extrabuf == NULL)) {
send_msg_channel_close(channel);
}
if (channel->recv_close && !write_pending(channel)) {
if (! channel->sent_close) { if (! channel->sent_close) {
TRACE(("Sending MSG_CHANNEL_CLOSE in response to same.")) TRACE(("Sending MSG_CHANNEL_CLOSE in response to same."))
send_msg_channel_close(channel); send_msg_channel_close(channel);
@ -274,8 +278,10 @@ static void check_close(struct Channel *channel) {
return; return;
} }
/* server chansession channels are special, since readfd mightn't #if 0
* close in the case of "sleep 4 & echo blah" until the sleep is up */ // The only use of check_close is "return channel->writefd == -1;" for a server
// chansession. Should be able to handle that with just the general
// socket close handling...?
if (channel->type->check_close) { if (channel->type->check_close) {
if (channel->type->check_close(channel)) { if (channel->type->check_close(channel)) {
close_write_fd(channel); close_write_fd(channel);
@ -283,6 +289,7 @@ static void check_close(struct Channel *channel) {
close_read_fd(channel, channel->errfd); close_read_fd(channel, channel->errfd);
} }
} }
#endif
if (!channel->sent_eof if (!channel->sent_eof
&& channel->readfd == FD_CLOSED && channel->readfd == FD_CLOSED
@ -296,25 +303,6 @@ static void check_close(struct Channel *channel) {
&& (channel->extrabuf != NULL || channel->errfd == FD_CLOSED)) { && (channel->extrabuf != NULL || channel->errfd == FD_CLOSED)) {
send_msg_channel_close(channel); send_msg_channel_close(channel);
} }
/* XXX blah */
if (channel->recv_eof &&
(cbuf_getused(channel->writebuf) == 0
&& (channel->extrabuf == NULL
|| cbuf_getused(channel->extrabuf) == 0))) {
close_write_fd(channel);
}
/* When either party wishes to terminate the channel, it sends
* SSH_MSG_CHANNEL_CLOSE. Upon receiving this message, a party MUST
* send back a SSH_MSG_CHANNEL_CLOSE unless it has already sent this
* message for the channel. The channel is considered closed for a
* party when it has both sent and received SSH_MSG_CHANNEL_CLOSE, and
* the party may then reuse the channel number. A party MAY send
* SSH_MSG_CHANNEL_CLOSE without having sent or received
* SSH_MSG_CHANNEL_EOF.
* (from draft-ietf-secsh-connect)
*/
} }
@ -398,9 +386,7 @@ static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf) {
len = write(fd, cbuf_readptr(cbuf, maxlen), maxlen); len = write(fd, cbuf_readptr(cbuf, maxlen), maxlen);
if (len <= 0) { if (len <= 0) {
if (len < 0 && errno != EINTR) { if (len < 0 && errno != EINTR) {
/* no more to write - we close it even if the fd was stderr, since close_chan_fd(channel, fd, SHUT_WR);
* that's a nasty failure too */
close_write_fd(channel);
} }
TRACE(("leave writechannel: len <= 0")) TRACE(("leave writechannel: len <= 0"))
return; return;
@ -409,6 +395,13 @@ static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf) {
cbuf_incrread(cbuf, len); cbuf_incrread(cbuf, len);
channel->recvdonelen += len; channel->recvdonelen += len;
/* We're closing out */
if (channel->recv_eof && cbuf_getused(cbuf) == 0) {
TRACE(("leave writechannel"))
close_chan_fd(channel, fd, SHUT_WR);
return;
}
/* Window adjust handling */ /* Window adjust handling */
if (channel->recvdonelen >= RECV_WINDOWEXTEND) { if (channel->recvdonelen >= RECV_WINDOWEXTEND) {
/* Set it back to max window */ /* Set it back to max window */
@ -572,16 +565,12 @@ void recv_msg_channel_request() {
* chan is the remote channel, isextended is 0 if it is normal data, 1 * chan is the remote channel, isextended is 0 if it is normal data, 1
* if it is extended data. if it is extended, then the type is in * if it is extended data. if it is extended, then the type is in
* exttype */ * exttype */
static void send_msg_channel_data(struct Channel *channel, int isextended, static void send_msg_channel_data(struct Channel *channel, int isextended) {
unsigned int exttype) {
int len; int len;
size_t maxlen, size_pos; size_t maxlen, size_pos;
int fd; int fd;
/* TRACE(("enter send_msg_channel_data"))
TRACE(("extended = %d type = %d", isextended, exttype))*/
CHECKCLEARTOWRITE(); CHECKCLEARTOWRITE();
dropbear_assert(!channel->sent_close); dropbear_assert(!channel->sent_close);
@ -608,7 +597,7 @@ static void send_msg_channel_data(struct Channel *channel, int isextended,
isextended ? SSH_MSG_CHANNEL_EXTENDED_DATA : SSH_MSG_CHANNEL_DATA); isextended ? SSH_MSG_CHANNEL_EXTENDED_DATA : SSH_MSG_CHANNEL_DATA);
buf_putint(ses.writepayload, channel->remotechan); buf_putint(ses.writepayload, channel->remotechan);
if (isextended) { if (isextended) {
buf_putint(ses.writepayload, exttype); buf_putint(ses.writepayload, SSH_EXTENDED_DATA_STDERR);
} }
/* a dummy size first ...*/ /* a dummy size first ...*/
size_pos = ses.writepayload->pos; size_pos = ses.writepayload->pos;
@ -618,7 +607,7 @@ static void send_msg_channel_data(struct Channel *channel, int isextended,
len = read(fd, buf_getwriteptr(ses.writepayload, maxlen), maxlen); len = read(fd, buf_getwriteptr(ses.writepayload, maxlen), maxlen);
if (len <= 0) { if (len <= 0) {
if (len == 0 || errno != EINTR) { if (len == 0 || errno != EINTR) {
close_read_fd(channel, fd); close_chan_fd(channel, fd, SHUT_RD);
} }
ses.writepayload->len = ses.writepayload->pos = 0; ses.writepayload->len = ses.writepayload->pos = 0;
TRACE(("leave send_msg_channel_data: read err or EOF for fd %d", TRACE(("leave send_msg_channel_data: read err or EOF for fd %d",
@ -891,6 +880,47 @@ static void send_msg_channel_open_confirmation(struct Channel* channel,
TRACE(("leave send_msg_channel_open_confirmation")) TRACE(("leave send_msg_channel_open_confirmation"))
} }
/* close a fd, how is SHUT_RD or SHUT_WR */
static void close_chan_fd(struct Channel *channel, int fd, int how) {
int closein = 0, closeout = 0;
if (channel->type->sepfds) {
TRACE(("shutdown((%d), %d)", fd, how))
shutdown(fd, how);
if (how == 0) {
closeout = 1;
} else {
closein = 1;
}
} else {
close(fd);
closein = closeout = 1;
}
if (closeout && fd == channel->readfd) {
channel->readfd = FD_CLOSED;
}
if (closeout && (channel->extrabuf == NULL) && (fd == channel->errfd)) {
channel->errfd = FD_CLOSED;
}
if (closein && fd == channel->writefd) {
channel->writefd = FD_CLOSED;
}
if (closein && (channel->extrabuf != NULL) && (fd == channel->errfd)) {
channel->errfd = FD_CLOSED;
}
/* if we called shutdown on it and all references are gone, then we
* need to close() it to stop it lingering */
if (channel->type->sepfds && channel->readfd == FD_CLOSED
&& channel->writefd == FD_CLOSED && channel->errfd == FD_CLOSED) {
close(fd);
}
}
#if defined(USING_LISTENERS) || defined(DROPBEAR_CLIENT) #if defined(USING_LISTENERS) || defined(DROPBEAR_CLIENT)
/* Create a new channel, and start the open request. This is intended /* Create a new channel, and start the open request. This is intended
* for X11, agent, tcp forwarding, and should be filled with channel-specific * for X11, agent, tcp forwarding, and should be filled with channel-specific
@ -980,61 +1010,3 @@ void recv_msg_channel_open_failure() {
remove_channel(channel); remove_channel(channel);
} }
#endif /* USING_LISTENERS */ #endif /* USING_LISTENERS */
/* close a stdout/stderr fd */
static void close_read_fd(struct Channel * channel, int fd) {
/* don't close it if it is the same as writefd,
* unless writefd is already set -1 */
TRACE(("enter close_read_fd"))
close_chan_fd(channel, fd, 0);
TRACE(("leave close_read_fd"))
}
/* close a stdin fd */
static void close_write_fd(struct Channel * channel) {
TRACE(("enter close_write_fd"))
close_chan_fd(channel, channel->writefd, 1);
TRACE(("leave close_write_fd"))
}
/* close a fd, how is 0 for stdout/stderr, 1 for stdin */
static void close_chan_fd(struct Channel *channel, int fd, int how) {
int closein = 0, closeout = 0;
if (channel->type->sepfds) {
TRACE(("shutdown((%d), %d)", fd, how))
shutdown(fd, how);
if (how == 0) {
closeout = 1;
} else {
closein = 1;
}
} else {
close(fd);
closein = closeout = 1;
}
if (closeout && fd == channel->readfd) {
channel->readfd = FD_CLOSED;
}
if (closeout && (channel->extrabuf == NULL) && (fd == channel->errfd)) {
channel->errfd = FD_CLOSED;
}
if (closein && fd == channel->writefd) {
channel->writefd = FD_CLOSED;
}
if (closein && (channel->extrabuf != NULL) && (fd == channel->errfd)) {
channel->errfd = FD_CLOSED;
}
/* if we called shutdown on it and all references are gone, then we
* need to close() it to stop it lingering */
if (channel->type->sepfds && channel->readfd == FD_CLOSED
&& channel->writefd == FD_CLOSED && channel->errfd == FD_CLOSED) {
close(fd);
}
}

2
debug.h
View File

@ -39,7 +39,7 @@
* Caution: Don't use this in an unfriendly environment (ie unfirewalled), * Caution: Don't use this in an unfriendly environment (ie unfirewalled),
* since the printing may not sanitise strings etc. This will add a reasonable * since the printing may not sanitise strings etc. This will add a reasonable
* amount to your executable size. */ * amount to your executable size. */
/*#define DEBUG_TRACE */ #define DEBUG_TRACE
/* All functions writing to the cleartext payload buffer call /* All functions writing to the cleartext payload buffer call
* CHECKCLEARTOWRITE() before writing. This is only really useful if you're * CHECKCLEARTOWRITE() before writing. This is only really useful if you're