8158e7716c
Added README; modified sigkill_rain.c to be more understandable, made clone.c compile; added wait_must_be_interruptible.c test; updated Makefile and .gitignore. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
84 lines
1.6 KiB
C
84 lines
1.6 KiB
C
#include <unistd.h>
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#include <sys/types.h>
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#include <signal.h>
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#include <sys/wait.h>
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#include <stdio.h>
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/* Expected order is:
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* Child signals parent
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* Parent got signal
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* Child will exit now
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*
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* The bug we test for: under strace -f, last two lines are swapped
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* because wait syscall is suspended by strace and thus can't be interrupted.
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*/
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static const char msg1[] = "Child signals parent\n";
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static const char msg2[] = "Parent got signal\n";
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static const char msg3[] = "Child will exit now\n";
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static void handler(int s)
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{
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write(1, msg2, sizeof(msg2)-1);
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}
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static void test()
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{
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/* Note: in Linux, signal() installs handler with SA_RESTART flag,
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* therefore wait will be restarted.
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*/
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signal(SIGALRM, handler);
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if (fork() == 0) {
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/* child */
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sleep(1);
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write(1, msg1, sizeof(msg1)-1);
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kill(getppid(), SIGALRM);
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sleep(1);
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write(1, msg3, sizeof(msg3)-1);
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_exit(0);
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}
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/* parent */
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wait(NULL);
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_exit(0);
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}
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int main()
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{
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char buf1[80];
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char buf2[80];
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char buf3[80];
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int pipefd[2];
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printf("Please run me under 'strace -f'\n");
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pipe(pipefd);
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if (fork() == 0) {
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if (pipefd[1] != 1) {
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dup2(pipefd[1], 1);
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close(pipefd[1]);
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}
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test();
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}
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if (pipefd[0] != 0) {
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dup2(pipefd[0], 0);
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close(pipefd[0]);
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}
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fgets(buf1, 80, stdin); printf("%s", buf1);
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fgets(buf2, 80, stdin); printf("%s", buf2);
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fgets(buf3, 80, stdin); printf("%s", buf3);
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if (strcmp(buf1, msg1) != 0
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|| strcmp(buf2, msg2) != 0
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|| strcmp(buf3, msg3) != 0
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) {
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printf("ERROR! Expected order:\n%s%s%s", msg1, msg2, msg3);
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return 1;
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}
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printf("Good: wait seems to be correctly interrupted by signals\n");
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return 0;
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}
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