57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
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/*
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* Test name: test13a.c
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*
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* Objective: The purpose of this tests is to show how a select can
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* get into a race condition when dealing with signals.
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*
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* Description: The program waits for SIGHUP or input in the terminal
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*/
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#include <sys/types.h>
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#include <sys/select.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <time.h>
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#include <stdio.h>
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#include <signal.h>
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#include <errno.h>
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int got_sighup = 0;
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void catch_hup(int sig_num)
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{
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printf("Received a SIGHUP, set global vble \n");
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got_sighup = 1;
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}
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int main(void) {
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int ret; /* return value */
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fd_set read_fds;
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char data[1024];
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/* Init read fd_set */
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FD_ZERO(&read_fds);
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FD_SET(0, &read_fds);
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/* set the HUP signal handler to 'catch_hup' */
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signal(SIGHUP, catch_hup);
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/* Get proc_id and print it */
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printf("Send a signal from other terminal with: kill -1 %d\n", getpid());
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printf("Going to sleep for 5 seconds, if the signal arrives meanwhile\n");
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printf("the process will be blocked until there is input in the keyboard\n");
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printf("if the signal arrives after the timeout and while in select, it will\n");
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printf("behave as it should.\n");
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printf("Sleeping for 5 secs\n");
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sleep(5);
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printf("Blocking now on select...\n");
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ret = select(1, &read_fds, NULL, NULL, NULL);
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if (got_sighup) {
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printf("We have a sighup signal so exit the program\n");
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exit(0);
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}
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gets(data);
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printf("Got entry for terminal then, bye\n");
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}
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