GUAC-803: Write to terminal STDOUT using length-prefixed packets, such that zero-length writes are legal.

This commit is contained in:
Michael Jumper 2015-02-04 13:08:02 -08:00
parent 4ab6466226
commit c39201cd8b
6 changed files with 224 additions and 4 deletions

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@ -34,6 +34,7 @@ noinst_HEADERS = \
cursor.h \ cursor.h \
display.h \ display.h \
ibar.h \ ibar.h \
packet.h \
pointer.h \ pointer.h \
scrollbar.h \ scrollbar.h \
terminal.h \ terminal.h \
@ -48,6 +49,7 @@ libguac_terminal_la_SOURCES = \
cursor.c \ cursor.c \
display.c \ display.c \
ibar.c \ ibar.c \
packet.c \
pointer.c \ pointer.c \
scrollbar.c \ scrollbar.c \
terminal.c \ terminal.c \

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@ -108,3 +108,23 @@ 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;
}

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@ -52,5 +52,26 @@ bool guac_terminal_has_glyph(int codepoint);
*/ */
int guac_terminal_write_all(int fd, const char* buffer, int size); 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 #endif

67
src/terminal/packet.c Normal file
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@ -0,0 +1,67 @@
/*
* Copyright (C) 2015 Glyptodon LLC
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#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;
}

92
src/terminal/packet.h Normal file
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@ -0,0 +1,92 @@
/*
* Copyright (C) 2015 Glyptodon LLC
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#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

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@ -29,6 +29,7 @@
#include "display.h" #include "display.h"
#include "ibar.h" #include "ibar.h"
#include "guac_clipboard.h" #include "guac_clipboard.h"
#include "packet.h"
#include "pointer.h" #include "pointer.h"
#include "scrollbar.h" #include "scrollbar.h"
#include "terminal.h" #include "terminal.h"
@ -324,7 +325,7 @@ void guac_terminal_free(guac_terminal* term) {
int guac_terminal_render_frame(guac_terminal* terminal) { int guac_terminal_render_frame(guac_terminal* terminal) {
guac_client* client = terminal->client; guac_client* client = terminal->client;
char buffer[8192]; char buffer[GUAC_TERMINAL_PACKET_SIZE];
int ret_val; int ret_val;
int fd = terminal->stdout_pipe_fd[0]; int fd = terminal->stdout_pipe_fd[0];
@ -348,7 +349,8 @@ int guac_terminal_render_frame(guac_terminal* terminal) {
guac_terminal_lock(terminal); guac_terminal_lock(terminal);
/* Read data, write to terminal */ /* Read data, write to terminal */
if ((bytes_read = read(fd, buffer, sizeof(buffer))) > 0) { if ((bytes_read = guac_terminal_packet_read(fd,
buffer, sizeof(buffer))) > 0) {
if (guac_terminal_write(terminal, buffer, bytes_read)) { if (guac_terminal_write(terminal, buffer, bytes_read)) {
guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, "Error writing data"); guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, "Error writing data");
@ -382,8 +384,24 @@ int guac_terminal_read_stdin(guac_terminal* terminal, char* c, int size) {
return read(stdin_fd, c, size); return read(stdin_fd, c, size);
} }
int guac_terminal_write_stdout(guac_terminal* terminal, const char* c, int size) { int guac_terminal_write_stdout(guac_terminal* terminal, const char* c,
return guac_terminal_write_all(terminal->stdout_pipe_fd[1], c, size); int size) {
/* Write maximally-sized packets until only one packet remains */
while (size > GUAC_TERMINAL_PACKET_SIZE) {
/* Write maximally-sized packet */
if (guac_terminal_packet_write(terminal->stdout_pipe_fd[1], c,
GUAC_TERMINAL_PACKET_SIZE) < 0)
return -1;
/* Advance to next packet */
c += GUAC_TERMINAL_PACKET_SIZE;
size -= GUAC_TERMINAL_PACKET_SIZE;
}
return guac_terminal_packet_write(terminal->stdout_pipe_fd[1], c, size);
} }
int guac_terminal_printf(guac_terminal* terminal, const char* format, ...) { int guac_terminal_printf(guac_terminal* terminal, const char* format, ...) {