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GUAC-654: Add missing comments to telnet_client.c

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This commit is contained in:
Michael Jumper 2014-05-07 21:19:15 -07:00
parent ffb33ccea5
commit 13e205a0e5
1 changed files with 51 additions and 0 deletions
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51
src/protocols/telnet/telnet_client.c
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@ -41,6 +41,10 @@
#include <guacamole/socket.h>
#include <libtelnet.h>
/**
* Support levels for various telnet options, required for connection
* negotiation by telnet_init(), part of libtelnet.
*/
static const telnet_telopt_t __telnet_options[] = {
{ TELNET_TELOPT_ECHO, TELNET_WONT, TELNET_DO },
{ TELNET_TELOPT_TTYPE, TELNET_WILL, TELNET_DONT },
@ -50,6 +54,16 @@ static const telnet_telopt_t __telnet_options[] = {
{ -1, 0, 0 }
};
/**
* Write the entire buffer given to the specified file descriptor, retrying
* the write automatically if necessary. This function will return a value
* not equal to the buffer's size iff an error occurs which prevents all
* future writes.
*
* @param fd The file descriptor to write to.
* @param buffer The buffer to write.
* @param size The number of bytes from the buffer to write.
*/
static int __guac_telnet_write_all(int fd, const char* buffer, int size) {
int remaining = size;
@ -70,6 +84,11 @@ static int __guac_telnet_write_all(int fd, const char* buffer, int size) {
}
/**
* Event handler, as defined by libtelnet. This function is passed to
* telnet_init() and will be called for every event fired by libtelnet,
* including feature enable/disable and receipt/transmission of data.
*/
static void __guac_telnet_event_handler(telnet_t* telnet, telnet_event_t* event, void* data) {
guac_client* client = (guac_client*) data;
@ -134,6 +153,14 @@ static void __guac_telnet_event_handler(telnet_t* telnet, telnet_event_t* event,
}
/**
* Input thread, started by the main telnet client thread. This thread
* continuously reads from the terminal's STDIN and transfers all read
* data to the telnet connection.
*
* @param data The current guac_client instance.
* @return Always NULL.
*/
static void* __guac_telnet_input_thread(void* data) {
guac_client* client = (guac_client*) data;
@ -153,6 +180,14 @@ static void* __guac_telnet_input_thread(void* data) {
}
/**
* Connects to the telnet server specified within the data associated
* with the given guac_client, which will have been populated by
* guac_client_init.
*
* @return The connected telnet instance, if successful, or NULL if the
* connection fails for any reason.
*/
static telnet_t* __guac_telnet_create_session(guac_client* client) {
int retval;
@ -243,6 +278,13 @@ static telnet_t* __guac_telnet_create_session(guac_client* client) {
}
/**
* Sends a 16-bit value over the given telnet connection with the byte order
* required by the telnet protocol.
*
* @param telnet The telnet connection to use.
* @param value The value to send.
*/
static void __guac_telnet_send_uint16(telnet_t* telnet, uint16_t value) {
unsigned char buffer[2];
@ -260,6 +302,15 @@ void guac_telnet_send_naws(telnet_t* telnet, uint16_t width, uint16_t height) {
telnet_finish_sb(telnet);
}
/**
* Waits for data on the given file descriptor for up to one second. The
* return value is identical to that of select(): 0 on timeout, < 0 on
* error, and > 0 on success.
*
* @param socket_fd The file descriptor to wait for.
* @return A value greater than zero on success, zero on timeout, and
* less than zero on error.
*/
static int __guac_telnet_wait(int socket_fd) {
fd_set fds;