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GUACAMOLE-269: Remove all dynamic allocation and simplify implementation.

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This commit is contained in:
Nick Couchman 2018-03-08 09:32:19 -05:00
parent dd7522bd9f
commit 45b832bfdc
3 changed files with 61 additions and 132 deletions
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19
src/protocols/ssh/ssh.c
View File

@ -193,7 +193,8 @@ void* ssh_client_thread(void* data) {
}
/* Initialize a ttymode array */
guac_ssh_ttymodes* ssh_ttymodes = guac_ssh_ttymodes_init(1);
const int num_tty_opcodes = 1;
char ssh_ttymodes[(GUAC_SSH_TTY_OPCODE_SIZE * num_tty_opcodes) + 1];
/* Set up screen recording, if requested */
if (settings->recording_path != NULL) {
@ -212,9 +213,6 @@ void* ssh_client_thread(void* data) {
settings->resolution, settings->width, settings->height,
settings->color_scheme, settings->backspace);
/* Add the backspace key to the ttymode array */
guac_ssh_ttymodes_add(ssh_ttymodes, GUAC_SSH_TTY_OP_VERASE, settings->backspace);
/* Fail if terminal init failed */
if (ssh_client->term == NULL) {
guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR,
@ -303,22 +301,19 @@ void* ssh_client_thread(void* data) {
}
/* Get char pointer array for TTY Mode Encoding */
int ttymode_size = guac_ssh_ttymodes_size(ssh_ttymodes);
char* ttymode_array = guac_ssh_ttymodes_to_array(ssh_ttymodes, ttymode_size);
/* Set up the ttymode array prior to requesting the PTY */
if (guac_ssh_ttymodes_init(ssh_ttymodes, sizeof(ssh_ttymodes),
num_tty_opcodes, (guac_ssh_ttymode){ GUAC_SSH_TTY_OP_VERASE, settings->backspace}))
guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, "Error configuring TTY mode encoding.");
/* Request PTY */
if (libssh2_channel_request_pty_ex(ssh_client->term_channel, "linux", sizeof("linux")-1,
ttymode_array, ttymode_size, ssh_client->term->term_width,
ssh_ttymodes, sizeof(ssh_ttymodes), ssh_client->term->term_width,
ssh_client->term->term_height, 0, 0)) {
guac_client_abort(client, GUAC_PROTOCOL_STATUS_UPSTREAM_ERROR, "Unable to allocate PTY.");
return NULL;
}
/* We're done with TTY Mode Encoding, so free structures. */
free(ttymode_array);
free(ssh_ttymodes);
/* If a command is specified, run that instead of a shell */
if (settings->command != NULL) {
if (libssh2_channel_exec(ssh_client->term_channel, settings->command)) {

74
src/protocols/ssh/ttymode.c
View File

@ -20,58 +20,40 @@
#include "config.h"
#include "ttymode.h"
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
guac_ssh_ttymodes* guac_ssh_ttymodes_init(int max_opcodes) {
/* Allocate enough space for the max opcodes */
guac_ssh_ttymode* ttymode_array = malloc(sizeof(guac_ssh_ttymode) * max_opcodes);
int guac_ssh_ttymodes_init(char opcode_array[], const int array_size,
const int num_opcodes, ...) {
/* Set up the initial data structure. */
guac_ssh_ttymodes* empty_modes = malloc(sizeof(guac_ssh_ttymodes));
empty_modes->ttymode_array = ttymode_array;
empty_modes->num_opcodes = 0;
/* Initialize the variable argument list. */
va_list args;
va_start(args, num_opcodes);
return empty_modes;
/* Check to make sure the array has enough space.
We need one extra byte at the end for the ending opcode. */
if ((num_opcodes * GUAC_SSH_TTY_OPCODE_SIZE) >= (array_size))
return 1;
for (int i = 0; i < num_opcodes; i++) {
/* Calculate offset in array */
int offset = i * GUAC_SSH_TTY_OPCODE_SIZE;
/* Get the next argument to this function */
guac_ssh_ttymode ttymode = va_arg(args, guac_ssh_ttymode);
/* Place opcode and value in array */
opcode_array[offset] = ttymode.opcode;
opcode_array[offset + 1] = (ttymode.value >> 24) & 0xFF;
opcode_array[offset + 2] = (ttymode.value >> 16) & 0xFF;
opcode_array[offset + 3] = (ttymode.value >> 8) & 0xFF;
opcode_array[offset + 4] = ttymode.value & 0xFF;
}
void guac_ssh_ttymodes_add(guac_ssh_ttymodes *tty_modes, char opcode, uint32_t value) {
/* Increment number of opcodes */
tty_modes->num_opcodes++;
/* Put the end opcode in the last opcode space */
opcode_array[num_opcodes * GUAC_SSH_TTY_OPCODE_SIZE] = GUAC_SSH_TTY_OP_END;
return 0;
/* Add new values */
tty_modes->ttymode_array[tty_modes->num_opcodes - 1].opcode = opcode;
tty_modes->ttymode_array[tty_modes->num_opcodes - 1].value = value;
}
int guac_ssh_ttymodes_size(guac_ssh_ttymodes *tty_modes) {
/* Each opcode pair is 5 bytes (1 opcode, 4 value)
Add one for the ending opcode */
return (tty_modes->num_opcodes * 5) + 1;
}
char* guac_ssh_ttymodes_to_array(guac_ssh_ttymodes *tty_modes, int data_size) {
char* temp = malloc(data_size);
/* Loop through the array based on number of tracked
opcodes and convert each one. */
for (int i = 0; i < tty_modes->num_opcodes; i++) {
int idx = i * 5;
uint32_t value = tty_modes->ttymode_array[i].value;
/* Opcode goes in first byte. */
temp[idx] = tty_modes->ttymode_array[i].opcode;
/* Convert 32-bit int to individual bytes. */
temp[idx+1] = (value >> 24) & 0xFF;
temp[idx+2] = (value >> 16) & 0xFF;
temp[idx+3] = (value >> 8) & 0xFF;
temp[idx+4] = value & 0xFF;
}
/* Add the ending opcode */
temp[data_size - 1] = GUAC_SSH_TTY_OP_END;
return temp;
}

104
src/protocols/ssh/ttymode.h
View File

@ -24,6 +24,14 @@
#include <stdint.h>
/**
* The size of a TTY mode encoding opcode and
* value pair. As defined in the SSH RFC, this
* is 5 bytes - a single byte for the opcode, and
* 4 bytes for the value.
*/
#define GUAC_SSH_TTY_OPCODE_SIZE 5
/**
* The SSH TTY mode encoding opcode that terminates
* the list of TTY modes.
@ -31,15 +39,15 @@
#define GUAC_SSH_TTY_OP_END 0
/**
* The SSH tty mode encoding opcode that configures
* The SSH TTY mode encoding opcode that configures
* the TTY erase code to configure the server
* backspace key.
*/
#define GUAC_SSH_TTY_OP_VERASE 3
/**
* A data type which holds a single opcode
* and the value for that opcode.
* Simple structure that defines a opcode and
* value pair.
*/
typedef struct guac_ssh_ttymode {
char opcode;
@ -47,82 +55,26 @@ typedef struct guac_ssh_ttymode {
} guac_ssh_ttymode;
/**
* A data type which holds an array of
* guac_ssh_ttymode data, along with the count of
* the number of opcodes currently in the array.
*/
typedef struct guac_ssh_ttymodes {
guac_ssh_ttymode* ttymode_array;
int num_opcodes;
} guac_ssh_ttymodes;
/**
* Initialize an empty guac_ssh_ttymodes data structure,
* with a null array of guac_ssh_ttymode and opcodes
* set to zero.
* Initialize an array with the specified opcode/value
* pairs, and return the size, in bytes, of the array.
*
* @param max_opcodes
* The maximum number of opcodes that will be allocated.
* @param opcode_array
* Pointer to the opcode array.
*
* @param array_size
* Size, in bytes, of the array.
*
* @param num_opcodes
* Number of opcodes to expect.
*
* @params ...
* A variable number of guac_ssh_ttymodes
* to place in the array.
*
* @return
* The pointer array for the gauc_ssh_ttymodes data
* structure generated by the function.
* The size, in bytes, of the array.
*/
guac_ssh_ttymodes* guac_ssh_ttymodes_init(int max_opcodes);
/**
* Add an item to the opcode array. This resizes the
* array, increments the number of opcodes, and adds
* the specified opcode and value pair to the data
* structure.
*
* @param tty_modes
* The pointer to the guac_ssh_ttymodes data structure
* to add the opcode to.
*
* @param opcode
* The single byte opcode as documented in section 8
* of the SSH RFC.
*
* @param value
* The four byte value of the opcodeto add to the
* guac_ssh_ttymodes data structure.
*/
void guac_ssh_ttymodes_add(guac_ssh_ttymodes *tty_modes, char opcode, uint32_t value);
/**
* Retrieve the size, in bytes, of the ttymode_array
* in the given guac_ssh_ttymodes data structure.
*
* @param tty_modes
* The pointer to the guac_ssh_ttymodes structure
* whose size we are curious about.
*
* @return
* The number of bytes of the opcodes and value paris
* in the data structure.
*/
int guac_ssh_ttymodes_size(guac_ssh_ttymodes *tty_modes);
/**
* Convert the ttymodes data structure into a char
* pointer array suitable for passing into the
* libssh2_channel_request_pty_ex() function.
*
* @param tty_modes
* The pointer to the guac_ssh_ttymodes structure
* that contains the opcode and value pairs
* we want to convert to a character pointer array.
*
* @param data_size
* The size of the resulting character pointer
* array.
*
* @return
* The character pointer array of opcode and
* value pairs to be passed to a SSH session.
*/
char* guac_ssh_ttymodes_to_array(guac_ssh_ttymodes *tty_modes, int data_size);
int guac_ssh_ttymodes_init(char opcode_array[], const int array_size,
const int num_opcodes, ...);
#endif