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Hi group,
I have a simple test program that opens a pipe to a sh command. I want to be able to send a CTRL-D to the child. I have tried reading from the parent's keyboard and using a write but this does not product the correct results.
Any suggestions?
Thanks for your time.
If by "send a Ctrl-D" you mean you want to close the pipe, just call close on the other end of the pipe. "Ctrl-D" is just an arbitrary way of telling the OS to send the eof signal to a process that is reading from the keyboard.
Depending on your code, it's likely that the write end of the pipe (presumably your sh command) automatically closes and sends the eof signal back to the parent.
Post your code if you want more detailed help.
The problem is if the sh hangs waiting for more input. I need a way of sending EOF to the shell. right now, I am looking at termios and catching CTRL-D signal. Nether one has provided a solution. Here is the code:Quote:
Originally Posted by algorism
Thanks for your time.Code:#define _GNU_SOURCE
#include <fcntl.h>
#include <stdlib.h>
#include <ctype.h>
#include <ncurses.h>
#include <string.h>
#include <linux/input.h>
#include <sys/types.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <poll.h>
#include <termios.h>
#include <unistd.h>
#define BS 7
#define TAB 9
#define ESC 27
#define NEWLINE 10
#define LEFT 4
#define UP 3
#define RIGHT 5
#define DOWN 2
#define INSERT 75
#define HEADER 5
#define streql( str1, str2 ) !strcmp( str1, str2 )
#define OFF "\x1B[0;0;0m"
#define DEFAULT "\x1B[0;0;0m"
#define RED "\x1B[1;31;40m"
#define BLUE "\x1B[1;34;40m"
#define GREEN "\x1B[1;32;40m"
#define YELLOW "\x1B[1;33;40m"
#define PURPLE "\x1B[1;35;40m"
#define CLEAR_EOL "\x1B[K"
int Fork = 0;
FILE *Parent_Out;
FILE *Parent_In;
FILE *Child_Out;
FILE *Child_In;
FILE *Log;
int Parent[2];
int Child[ 2];
int X_Size, Y_Size, CMD_Line, PRT_Line, X, Y, RC, EOD;
char Message[500];
int C;
int EOL;
int old = 0;
int mode = 3;
int Home = 5;
int Index = 0;
int Debug = 0;
int Insert = 0;
int Length = 0;
int Cursor = 5;
fd_set FD_Table;
int Quit();
void
CTRL_Z( int Signal ) {
kill( Fork, SIGTSTP );
signal( SIGTSTP, CTRL_Z ); }
void
CTRL_C( int Signal ) {
kill( Fork, SIGINT );
signal( SIGINT, CTRL_C ); }
void
CTRL_D( int Signal ) {
kill( Fork, SIGINT );
signal( SIGINT, CTRL_C ); }
int
main( int argc, char *argv[] ) { // Main
signal( SIGTSTP, CTRL_Z );
signal( SIGINT, CTRL_C );
Log = fopen( "Log", "w" );
int x, y, I;
for( I = 0; I < argc; I++ ) {
if( !strcmp( argv[I], "d" )) Debug = 1; }
unsigned char msg_buf[80];
unsigned char net_buf[80];
unsigned char cmd_buf[80];
bzero (msg_buf, 80);
bzero (net_buf, 80);
bzero (cmd_buf, 80);
char *Current;
char Buf[256];
char Con[256];
int P, R, F, errno, Wheel = 0, Cnt;
int Display;
Current = cmd_buf;
if( Fork == 0 ) { // Create child process
if( ( pipe2( Parent, O_CLOEXEC ) ) == -1 ) {
perror( "Parent pipe failed" );
exit(1); }
if( ( pipe2( Child, O_CLOEXEC ) ) == -1 ) {
perror( "Child pipe failed" );
exit(1); }
if( ( Fork = fork() ) == -1 ) {
perror("Fork failed");
return 1; }
if( Fork == 0 ) {
/* Child process closes up input side of pipe */
dup2( Child[0], 0 );
Child_In = fdopen( 0, "r" );
close( Child[0] );
dup2( Parent[1], 1 );
dup2( Parent[1], 2 );
Parent_In = fdopen( 1, "w" );
close( Parent[1] );
char Fork[] = "sh";
char *Argv[] = { "sh", "-", NULL };
if(( Display = execvp( Fork, Argv )) != 0 ) {
fputs( "Fork Command failed.\n", Log );
return 1; }
fputs( "env\n", Child_In );
while( 1 ) {
RC = read( Child[0], Buf, 256 );
fputs( Buf, Log );
system( Buf ); } }
else {
/* Parent process closes up output side of pipe */
Child_In = fdopen( Child[1], "w" );
Parent_In = fdopen( Parent[1], "w" ); }
struct termios new, old;
tcgetattr( 0, &old );
signal( SIGINT, CTRL_D );
new = old;
// term.c_iflag |= IGNBRK;
// term.c_iflag &= ~(INLCR | ICRNL | IXON | IXOFF);
// term.c_lflag &= ~(ICANON | ECHO | ECHOK | ECHOE | ECHONL | ISIG | IEXTEN);
// term.c_cc[VMIN] = 1;
// new.c_cc[VINTR] = 4;
tcsetattr( fileno( stdin ), TCSANOW, &new );
unsigned char Spiner[] = "/-\\|";
struct timeval Timer;
Timer.tv_sec = 0;
Timer.tv_usec = 250000;
P = Parent[0];
while( 1 ) { // While
Cnt = 0;
R = 1;
while( R ) { // While
FD_ZERO( &FD_Table );
FD_SET( 0, &FD_Table );
FD_SET( 4, &FD_Table );
FD_SET( 6, &FD_Table );
/*
if( ++Cnt > 10 ) {
R = 0;
printf( RED "\nTimeout" OFF "\n" );
fflush( NULL );
break; }
*/
int Count = select( P +1, &FD_Table, NULL, NULL, NULL );
if( Count < 0 ) {
printf( "Select Error %s\n", strerror(errno) );
return 0; }
/*
for( I = 0; I < 8; I++ ) {
if( FD_ISSET( I, &FD_Table ) ) {
printf( PURPLE "Is set: %d, Cnt: %d" OFF "\n", I, Cnt ); } }
*/
if( FD_ISSET( 0, &FD_Table )) {
bzero( Con, 256 );
printf( PURPLE "Enter: " OFF ); fflush( stdout );
if( ( RC = read( 0, Con, 256 ) ) > 0 ) {
printf( "%d ", RC );
for( I = 0; I < RC; I++ ) {
printf( "%02x", Con[I] ); }
printf( "\n" );
if( streql( Con, "q\n" ) ) Quit();
write( Child[1], Con, RC ); }
// fflush( Child[1] );
continue; }
if( FD_ISSET( 4, &FD_Table )) { // ISSET
printf( BLUE "Child_Out:\n" );
while(1) {
struct pollfd UFDS[1];
UFDS[0].fd = 4;
UFDS[0].events = POLLIN | POLLPRI;
RC = poll( UFDS, 1, 1 );
if( RC < 1 ) {
R = 0;
break; }
RC = read( 4, Buf, 256 );
if( streql( Buf, "\n" ) ) {
printf( "%s", Buf );
break; }
if( RC < 0 ) {
if( errno == EAGAIN ) break;
perror( "Read failed" );
break; }
if( RC == 0 ) break;
else {
sprintf( Message, "RC: %d, Buf: '%s'\n", RC, Buf );
fputs( Message, Log );
printf( Buf );
bzero( Buf, 256 );
continue; } }
printf( OFF );
fflush( stdout );
break; }
/*
if( Count == 0 ) {
if( ++Wheel > 3 ) Wheel = 0;
printf( CLEAR_EOL "%c %5.2f secs.\r", Spiner[ Wheel ],
(float) Cnt*.25 );
fflush( NULL ); }
*/
}
bzero( Current, 80 ); }
}
Quit(); }
/* --------------------------------------------------------- */
/* Clean up after ourselves */
int Quit() {
printf( RED "Terminated" OFF "\n" );
// kill( Child, 9 );
fclose( Log );
exit(0); }
/* --------------------------------------------------------- */
- too many global variables
- too many variables with meaningless names
- too badly formatted
- main is way too long (nearly 200 lines) for it's own good.
Oh, and your local errno variable masks the global errno variable that all the system calls set, so even that is broken.
Your code is extremely difficult to understand (although I sense it's trying to do something fairly simple). I don't feel like spending the time to sort it out. If you told me what it's supposed to do I bet I could write a program to do it in far less time than it would take me to disentangle your code. That's not a good sign.
EDIT: Writing a quick example of what I think you're trying to do gave me a little insight into what I think is your problem. Have you considered sending the command followed by the shell "exit" command so that the shell will exit. E.g., "ls\nexit\n".
IT IS A TEST PROGRAM!!!!!!!! The only comment worth while is about errno! Thanks for that.Quote:
Originally Posted by Salem
It's purpose is irrelevant if it's too long and unwieldy for you to debug effectively or for anyone else to invest time and effort in picking apart your program to find out what you did wrong.
Separate the code out into smaller functions you can test.
Nobody is going to look or care about your big ball of mud.