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GUACAMOLE-86: Remove terminal emulator's STDOUT pipe. Use pthread_cond_t to signal modification.

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This commit is contained in:
Michael Jumper 2017-01-15 15:31:33 -08:00
parent cf9aeef83b
commit e5b3af8ffe
9 changed files with 117 additions and 307 deletions
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2
src/protocols/ssh/ssh.c
View File

@ -339,7 +339,7 @@ void* ssh_client_thread(void* data) {
/* Attempt to write data received. Exit on failure. */
if (bytes_read > 0) {
int written = guac_terminal_write_stdout(ssh_client->term, buffer, bytes_read);
int written = guac_terminal_write(ssh_client->term, buffer, bytes_read);
if (written < 0)
break;

4
src/protocols/telnet/telnet.c
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@ -150,7 +150,7 @@ static void __guac_telnet_event_handler(telnet_t* telnet, telnet_event_t* event,
/* Terminal output received */
case TELNET_EV_DATA:
guac_terminal_write_stdout(telnet_client->term, event->data.buffer, event->data.size);
guac_terminal_write(telnet_client->term, event->data.buffer, event->data.size);
/* Continue search for username prompt */
if (settings->username_regex != NULL) {
@ -267,7 +267,7 @@ static void* __guac_telnet_input_thread(void* data) {
while ((bytes_read = guac_terminal_read_stdin(telnet_client->term, buffer, sizeof(buffer))) > 0) {
telnet_send(telnet_client->telnet, buffer, bytes_read);
if (telnet_client->echo_enabled)
guac_terminal_write_stdout(telnet_client->term, buffer, bytes_read);
guac_terminal_write(telnet_client->term, buffer, bytes_read);
}
return NULL;

2
src/terminal/Makefile.am
View File

@ -27,7 +27,6 @@ noinst_HEADERS = \
char_mappings.h \
common.h \
display.h \
packet.h \
scrollbar.h \
terminal.h \
terminal_handlers.h \
@ -39,7 +38,6 @@ libguac_terminal_la_SOURCES = \
char_mappings.c \
common.c \
display.c \
packet.c \
scrollbar.c \
terminal.c \
terminal_handlers.c \

20
src/terminal/common.c
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@ -105,23 +105,3 @@ int guac_terminal_write_all(int fd, const char* buffer, int size) {
}
int guac_terminal_fill_buffer(int fd, char* buffer, int size) {
int remaining = size;
while (remaining > 0) {
/* Attempt to read data */
int ret_val = read(fd, buffer, remaining);
if (ret_val <= 0)
return -1;
/* If successful, continue with what space remains (if any) */
remaining -= ret_val;
buffer += ret_val;
}
return size;
}

21
src/terminal/common.h
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@ -49,26 +49,5 @@ bool guac_terminal_has_glyph(int codepoint);
*/
int guac_terminal_write_all(int fd, const char* buffer, int size);
/**
* Similar to read, but automatically retries the read until an error occurs,
* filling all available space within the buffer. Unless it is known that the
* given amount of space is available on the file descriptor, there is a good
* chance this function will block.
*
* @param fd
* The file descriptor to read data from.
*
* @param buffer
* The buffer to store data within.
*
* @param size
* The number of bytes available within the buffer.
*
* @return
* The number of bytes read if successful, or a negative value if an error
* occurs.
*/
int guac_terminal_fill_buffer(int fd, char* buffer, int size);
#endif

64
src/terminal/packet.c
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@ -1,64 +0,0 @@
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
#include "common.h"
#include "packet.h"
#include <string.h>
int guac_terminal_packet_write(int fd, const void* data, int length) {
guac_terminal_packet out;
/* Do not attempt to write packets beyond maximum size */
if (length > GUAC_TERMINAL_PACKET_SIZE)
return -1;
/* Calculate final packet length */
int packet_length = sizeof(int) + length;
/* Copy data into packet */
out.length = length;
memcpy(out.data, data, length);
/* Write packet */
return guac_terminal_write_all(fd, (const char*) &out, packet_length);
}
int guac_terminal_packet_read(int fd, void* data, int length) {
int bytes;
/* Read buffers MUST be at least GUAC_TERMINAL_PACKET_SIZE */
if (length < GUAC_TERMINAL_PACKET_SIZE)
return -1;
/* Read length */
if (guac_terminal_fill_buffer(fd, (char*) &bytes, sizeof(int)) < 0)
return -1;
/* Read body */
if (guac_terminal_fill_buffer(fd, (char*) data, bytes) < 0)
return -1;
return bytes;
}

89
src/terminal/packet.h
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@ -1,89 +0,0 @@
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
#ifndef GUAC_TERMINAL_PACKET_H
#define GUAC_TERMINAL_PACKET_H
/**
* The maximum size of a packet written or read by the
* guac_terminal_packet_write() or guac_terminal_packet_read() functions.
*/
#define GUAC_TERMINAL_PACKET_SIZE 4096
/**
* An arbitrary data packet with minimal framing.
*/
typedef struct guac_terminal_packet {
/**
* The number of bytes in the data portion of this packet.
*/
int length;
/**
* Arbitrary data.
*/
char data[GUAC_TERMINAL_PACKET_SIZE];
} guac_terminal_packet;
/**
* Writes a single packet of data to the given file descriptor. The provided
* length MUST be no greater than GUAC_TERMINAL_PACKET_SIZE. Zero-length
* writes are legal and do result in a packet being written to the file
* descriptor.
*
* @param fd
* The file descriptor to write to.
*
* @param data
* A buffer containing the data to write.
*
* @param length
* The number of bytes to write to the file descriptor.
*
* @return
* The number of bytes written on success, which may be zero if the data
* length is zero, or a negative value on error.
*/
int guac_terminal_packet_write(int fd, const void* data, int length);
/**
* Reads a single packet of data from the given file descriptor. The provided
* length MUST be at least GUAC_TERMINAL_PACKET_SIZE to ensure any packet
* read will fit in the buffer. Zero-length reads are possible if a zero-length
* packet was written.
*
* @param fd
* The file descriptor to read from.
*
* @param data
* The buffer to store data within.
*
* @param length
* The number of bytes available within the buffer.
*
* @return
* The number of bytes read on success, which may be zero if the read
* packet had a length of zero, or a negative value on error.
*/
int guac_terminal_packet_read(int fd, void* data, int length);
#endif

185
src/terminal/terminal.c
View File

@ -24,7 +24,6 @@
#include "display.h"
#include "guac_clipboard.h"
#include "guac_cursor.h"
#include "packet.h"
#include "scrollbar.h"
#include "terminal.h"
#include "terminal_handlers.h"
@ -32,7 +31,6 @@
#include "typescript.h"
#include <errno.h>
#include <poll.h>
#include <pthread.h>
#include <stdarg.h>
#include <stdio.h>
@ -318,6 +316,11 @@ guac_terminal* guac_terminal_create(guac_client* client,
term->upload_path_handler = NULL;
term->file_download_handler = NULL;
/* Init modified flag and conditional */
term->modified = 0;
pthread_cond_init(&(term->modified_cond), NULL);
pthread_mutex_init(&(term->modified_lock), NULL);
/* Init buffer */
term->buffer = guac_terminal_buffer_alloc(1000, &default_char);
@ -349,14 +352,6 @@ guac_terminal* guac_terminal_create(guac_client* client,
term->term_width = available_width / term->display->char_width;
term->term_height = height / term->display->char_height;
/* Open STDOUT pipe */
if (pipe(term->stdout_pipe_fd)) {
guac_error = GUAC_STATUS_SEE_ERRNO;
guac_error_message = "Unable to open pipe for STDOUT";
free(term);
return NULL;
}
/* Open STDIN pipe */
if (pipe(term->stdin_pipe_fd)) {
guac_error = GUAC_STATUS_SEE_ERRNO;
@ -414,10 +409,6 @@ guac_terminal* guac_terminal_create(guac_client* client,
void guac_terminal_free(guac_terminal* term) {
/* Close terminal output pipe */
close(term->stdout_pipe_fd[1]);
close(term->stdout_pipe_fd[0]);
/* Close user input pipe */
close(term->stdin_pipe_fd[1]);
close(term->stdin_pipe_fd[0]);
@ -449,84 +440,110 @@ void guac_terminal_free(guac_terminal* term) {
}
/**
* Waits for data to become available on the given file descriptor.
* Populate the given timespec with the current time, plus the given offset.
*
* @param fd
* The file descriptor to wait on.
* @param ts
* The timespec structure to populate.
*
* @param offset_sec
* The offset from the current time to use when populating the given
* timespec, in seconds.
*
* @param offset_usec
* The offset from the current time to use when populating the given
* timespec, in microseconds.
*/
static void guac_terminal_get_absolute_time(struct timespec* ts,
int offset_sec, int offset_usec) {
/* Get timeval */
struct timeval tv;
gettimeofday(&tv, NULL);
/* Update with offset */
tv.tv_sec += offset_sec;
tv.tv_usec += offset_usec;
/* Wrap to next second if necessary */
if (tv.tv_usec >= 1000000) {
tv.tv_sec++;
tv.tv_usec -= 1000000;
}
/* Convert to timespec */
ts->tv_sec = tv.tv_sec;
ts->tv_nsec = tv.tv_usec * 1000;
}
/**
* Waits for the terminal state to be modified, returning only when the
* specified timeout has elapsed or a frame flush is desired. Note that the
* modified flag of the terminal will only be reset if no data remains to be
* read from STDOUT.
*
* @param terminal
* The terminal to wait on.
*
* @param msec_timeout
* The maximum amount of time to wait, in milliseconds.
*
* @return
* A positive if data is available, zero if the timeout has elapsed without
* data becoming available, or negative if an error occurred.
* Non-zero if the terminal has been modified, zero if the timeout has
* elapsed without the terminal being modified.
*/
static int guac_terminal_wait_for_data(int fd, int msec_timeout) {
static int guac_terminal_wait(guac_terminal* terminal, int msec_timeout) {
/* Build array of file descriptors */
struct pollfd fds[] = {{
.fd = fd,
.events = POLLIN,
.revents = 0,
}};
int retval = 1;
/* Wait for data */
return poll(fds, 1, msec_timeout);
pthread_mutex_t* mod_lock = &(terminal->modified_lock);
pthread_cond_t* mod_cond = &(terminal->modified_cond);
/* Split provided milliseconds into microseconds and whole seconds */
int secs = msec_timeout / 1000;
int usecs = (msec_timeout % 1000) * 1000;
/* Calculate absolute timestamp from provided relative timeout */
struct timespec timeout;
guac_terminal_get_absolute_time(&timeout, secs, usecs);
/* Test for terminal modification */
pthread_mutex_lock(mod_lock);
if (terminal->modified)
goto wait_complete;
/* If not yet modified, wait for modification condition to be signaled */
retval = pthread_cond_timedwait(mod_cond, mod_lock, &timeout) != ETIMEDOUT;
wait_complete:
/* Terminal is no longer modified */
terminal->modified = 0;
pthread_mutex_unlock(mod_lock);
return retval;
}
int guac_terminal_render_frame(guac_terminal* terminal) {
guac_client* client = terminal->client;
char buffer[GUAC_TERMINAL_PACKET_SIZE];
int wait_result;
int fd = terminal->stdout_pipe_fd[0];
/* Wait for data to be available */
wait_result = guac_terminal_wait_for_data(fd, 1000);
if (wait_result > 0) {
wait_result = guac_terminal_wait(terminal, 1000);
if (wait_result) {
guac_terminal_lock(terminal);
guac_timestamp frame_start = guac_timestamp_current();
do {
guac_timestamp frame_end;
int frame_remaining;
int bytes_read;
/* Read data, write to terminal */
if ((bytes_read = guac_terminal_packet_read(fd,
buffer, sizeof(buffer))) > 0) {
if (guac_terminal_write(terminal, buffer, bytes_read)) {
guac_client_abort(client,
GUAC_PROTOCOL_STATUS_SERVER_ERROR,
"Error writing data");
guac_terminal_unlock(terminal);
return 1;
}
}
/* Notify on error */
if (bytes_read < 0) {
guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR,
"Error reading data");
guac_terminal_unlock(terminal);
return 1;
}
/* Calculate time remaining in frame */
frame_end = guac_timestamp_current();
frame_remaining = frame_start + GUAC_TERMINAL_FRAME_DURATION
guac_timestamp frame_end = guac_timestamp_current();
int frame_remaining = frame_start + GUAC_TERMINAL_FRAME_DURATION
- frame_end;
/* Wait again if frame remaining */
if (frame_remaining > 0)
wait_result = guac_terminal_wait_for_data(fd,
wait_result = guac_terminal_wait(terminal,
GUAC_TERMINAL_FRAME_TIMEOUT);
else
break;
@ -534,18 +551,12 @@ int guac_terminal_render_frame(guac_terminal* terminal) {
} while (wait_result > 0);
/* Flush terminal */
guac_terminal_lock(terminal);
guac_terminal_flush(terminal);
guac_terminal_unlock(terminal);
}
/* Notify of any errors */
if (wait_result < 0) {
guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR,
"Error waiting for data");
return 1;
}
return 0;
}
@ -555,28 +566,19 @@ int guac_terminal_read_stdin(guac_terminal* terminal, char* c, int size) {
return read(stdin_fd, c, size);
}
int guac_terminal_write_stdout(guac_terminal* terminal, const char* c,
int size) {
void guac_terminal_notify(guac_terminal* terminal) {
/* Write maximally-sized packets until only one packet remains */
while (size > GUAC_TERMINAL_PACKET_SIZE) {
pthread_mutex_t* mod_lock = &(terminal->modified_lock);
pthread_cond_t* mod_cond = &(terminal->modified_cond);
/* Write maximally-sized packet */
if (guac_terminal_packet_write(terminal->stdout_pipe_fd[1], c,
GUAC_TERMINAL_PACKET_SIZE) < 0)
return -1;
pthread_mutex_lock(mod_lock);
/* Advance to next packet */
c += GUAC_TERMINAL_PACKET_SIZE;
size -= GUAC_TERMINAL_PACKET_SIZE;
/* Signal modification */
terminal->modified = 1;
pthread_cond_signal(mod_cond);
}
pthread_mutex_unlock(mod_lock);
return guac_terminal_packet_write(terminal->stdout_pipe_fd[1], c, size);
}
int guac_terminal_notify(guac_terminal* terminal) {
return guac_terminal_packet_write(terminal->stdout_pipe_fd[1], NULL, 0);
}
int guac_terminal_printf(guac_terminal* terminal, const char* format, ...) {
@ -595,7 +597,7 @@ int guac_terminal_printf(guac_terminal* terminal, const char* format, ...) {
return written;
/* Write to STDOUT */
return guac_terminal_write_stdout(terminal, buffer, written);
return guac_terminal_write(terminal, buffer, written);
}
@ -711,6 +713,7 @@ void guac_terminal_commit_cursor(guac_terminal* term) {
int guac_terminal_write(guac_terminal* term, const char* c, int size) {
guac_terminal_lock(term);
while (size > 0) {
/* Read and advance to next character */
@ -725,7 +728,9 @@ int guac_terminal_write(guac_terminal* term, const char* c, int size) {
term->char_handler(term, current);
}
guac_terminal_unlock(term);
guac_terminal_notify(term);
return 0;
}

35
src/terminal/terminal.h
View File

@ -159,13 +159,24 @@ struct guac_terminal {
pthread_mutex_t lock;
/**
* Pipe which should be written to (and read from) to provide output to
* this terminal. Another thread should read from this pipe when writing
* data to the terminal. It would make sense for the terminal to provide
* this thread, but for simplicity, that logic is left to the guac
* message handler (to give the message handler something to block with).
* The mutex associated with the modified condition and flag, locked
* whenever a thread is waiting on the modified condition, the modified
* condition is being signalled, or the modified flag is being changed.
*/
int stdout_pipe_fd[2];
pthread_mutex_t modified_lock;
/**
* Flag set whenever an operation has affected the terminal in a way that
* will require a frame flush. When this flag is set, the modified_cond
* condition will be signalled. The modified_lock will always be
* acquired before this flag is altered.
*/
int modified;
/**
* Condition which is signalled when the modified flag has been set
*/
pthread_cond_t modified_cond;
/**
* Pipe which will be the source of user input. When a terminal code
@ -473,24 +484,14 @@ int guac_terminal_render_frame(guac_terminal* terminal);
*/
int guac_terminal_read_stdin(guac_terminal* terminal, char* c, int size);
/**
* Writes to this terminal's STDOUT. This function may block until space
* is freed in the output buffer by guac_terminal_render_frame().
*/
int guac_terminal_write_stdout(guac_terminal* terminal, const char* c, int size);
/**
* Notifies the terminal that an event has occurred and the terminal should
* flush itself when reasonable.
*
* @param terminal
* The terminal to notify.
*
* @return
* Zero if notification succeeded, non-zero if an error occurred while
* notifying the terminal.
*/
int guac_terminal_notify(guac_terminal* terminal);
void guac_terminal_notify(guac_terminal* terminal);
/**
* Reads a single line from this terminal's STDIN, storing the result in a