hellisabove
96 lines
2.3 KiB
Plaintext
96 lines
2.3 KiB
Plaintext
#include <stropts.h>
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#include <poll.h>
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/*
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* Check whether or not a character is ready to be read, or time out.
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* This version uses a poll call.
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*
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* Args: time_out -- number of seconds before it will time out.
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*
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* Result: NO_OP_IDLE: timed out before any chars ready, time_out > 25
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* NO_OP_COMMAND: timed out before any chars ready, time_out <= 25
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* READ_INTR: read was interrupted
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* READY_TO_READ: input is available
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* BAIL_OUT: reading input failed, time to bail gracefully
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* PANIC_NOW: system call error, die now
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*/
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int
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input_ready(time_out)
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int time_out;
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{
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struct pollfd pollfd;
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int res;
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fflush(stdout);
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if(time_out > 0){
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/* Check to see if there are bytes to read with a timeout */
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pollfd.fd = STDIN_FD;
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pollfd.events = POLLIN;
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res = poll (&pollfd, 1, time_out * 1000);
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if(res >= 0){ /* status bits OK? */
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if(pollfd.revents & (POLLERR | POLLNVAL))
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res = -1; /* bad news, exit below! */
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else if(pollfd.revents & POLLHUP)
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return(BAIL_OUT);
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}
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if(res < 0){
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if(errno == EINTR || errno == EAGAIN)
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return(READ_INTR);
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return(PANIC_NOW);
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}
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if(res == 0){ /* the select timed out */
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if(getppid() == 1){
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/* Parent is init! */
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return(BAIL_OUT);
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}
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/*
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* "15" is the minimum allowed mail check interval.
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* Anything less, and we're being told to cycle thru
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* the command loop because some task is pending...
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*/
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return(time_out < IDLE_TIMEOUT ? NO_OP_COMMAND : NO_OP_IDLE);
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}
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}
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time_of_last_input = time((time_t *) 0);
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return(READY_TO_READ);
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}
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/*
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* Read one character from STDIN.
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*
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* Result: -- the single character read
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* READ_INTR -- read was interrupted
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* BAIL_OUT -- read error of some sort
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*/
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int
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read_one_char()
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{
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int res;
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unsigned char c;
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res = read(STDIN_FD, &c, 1);
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if(res <= 0){
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/*
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* Error reading from terminal!
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* The only acceptable failure is being interrupted. If so,
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* return a value indicating such...
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*/
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if(res < 0 && errno == EINTR)
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return(READ_INTR);
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else
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return(BAIL_OUT);
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}
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return((int)c);
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}
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