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Sending signal to inferior
- From: Carlos Eduardo Rodrigues de Almeida <eduardo dot almeida at gmail dot com>
- To: gdb at sources dot redhat dot com
- Date: Fri, 30 Dec 2005 03:37:00 +0000
- Subject: Sending signal to inferior
Hi all,
I'm trying to write a front-end to GDB.
For the first experiment I wrote a small program just to control gdb..
The program is at the end of the message
I run some program and I can't stop it sending a SIGINT to GDB
if I
kill -2 GDBPID
nothing happens
the only way to stop the inferior is to ps, get its pid and
kill -2 INFERIORPID
someone had this problem in the list but I couldn't find the
solution.. someone pointed to tgdb
http://cgdb.sourceforge.net/
I noticed something:
tgdb has a tgdb_driver that is exactly what I'm trying to do but using
tgdb.. a little program that controls gdb..
Running some program with tgdb_driver I get 3 process:
tgdb_driver
gdb (created by tgdb_driver)
inferior (created by gdb)
if I send a SIGINT to gdb it stops the inferior.
with my program I get:
echo
gdb
inferior
if I send a SIGINT to gdb, it DOES not stop the inferior...
I looked at the source code and it mentions the setsid() funcition:
/* If this is not called, when user types ^c SIGINT gets sent to gdb */
setsid();
but if I comment out this line it keeps working...
I couldn't find what tgdb does to stop the inferior when I send gdb
the SIGINT.. does someone can point me a solution?
Thank you!
Eduardo
The program I wrote:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <termio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
typedef struct _ARG {
int fd_read;
int fd_write;
}ARG;
char buf[2048];
int nRead;
int treatfd(void *arg);
int treatSTDIN(void *arg);
pid_t fork_status;
char cmd1[] = "file /home/eduardo/lab3/Debug/lab3\n";
char cmd2[] = "run\n";
char cmd3[] = "quit\n";
char cmd4[] = "\002";
int main(void) {
int stdin_pipe[2], stdout_pipe[2], stderr_pipe[2];
pthread_t tstdin, tstdout, tstderr;
ARG argstdin, argstdout, argstderr;
struct termio Termio;
int bwritten;
if( (pipe(stdin_pipe) != 0) || (pipe(stdout_pipe) != 0) ||
pipe(stderr_pipe) != 0) {
printf("Error creating pipes");
exit(1);
}
fork_status = fork();
if(fork_status == -1){
printf("Error forking");
exit(1);
}
/* Chield process */
else if(fork_status == 0) {
setsid();
close(0);
dup(stdin_pipe[0]);
close(stdin_pipe[0]);
close(stdin_pipe[1]);
close(1);
dup(stdout_pipe[1]);
close(stdout_pipe[0]);
close(stdout_pipe[1]);
close(2);
dup(stderr_pipe[1]);
close(stderr_pipe[0]);
close(stderr_pipe[1]);
// printf("executando gdb");
execlp("gdb", "gdb", (char *)0);
// printf("Error with execl");
exit(1);
}
/* Parent process */
else {
close(stdin_pipe[0]);
close(stdout_pipe[1]);
close(stderr_pipe[1]);
fd_set rdSet;
int max;
int selectRet;
max = (0 > stdout_pipe[0]) ? 0 : stdout_pipe[0];
max = (max > stderr_pipe[0]) ? max : stderr_pipe[0];
while(1) {
FD_ZERO(&rdSet);
FD_SET(0, &rdSet);
FD_SET(stdout_pipe[0], &rdSet);
FD_SET(stderr_pipe[0], &rdSet);
selectRet = select(max + 1, &rdSet, NULL, NULL, NULL);
if(selectRet == -1)
return;
if(FD_ISSET(0, &rdSet)) {
nRead = read(0, buf, 2048);
write(stdin_pipe[1], buf, nRead);
}
if(FD_ISSET(stdout_pipe[0], &rdSet)) {
nRead = read(stdout_pipe[0], buf, 2048);
if(nRead == 0)
return;
write(1, buf, nRead);
}
if(FD_ISSET(stderr_pipe[0], &rdSet)) {
nRead = read(stderr_pipe[0], buf, 2048);
if(nRead == 0)
return;
write(2, buf, nRead);
}
}
}
}