1ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown#include <stdio.h> 2ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown#include <unistd.h> 3ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown#include <signal.h> 4ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown#include <errno.h> 5ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown#include <sys/wait.h> 6ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown#include <string.h> 7ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 8ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown/* Make sure that a blocking syscall restarts if hit by a signal, 9ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown and SA_RESTART is set */ 10ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 11ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brownstatic void handler(int s) 12ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown{ 13ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown} 14ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 15ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brownint main() 16ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown{ 17ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown int pid; 18ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown int fds[2]; 19ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 20ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown if (pipe(fds) == -1) { 21ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown perror("FAIL: pipe\n"); 22ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown return 1; 23ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown } 24ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 25ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown pid = fork(); 26ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 27ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown if (pid == -1) { 28ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown perror("fork failed"); 29ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown return 1; 30ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown } 31ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 32ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown if (pid == 0) { 33ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown char ch = '?'; 34ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown int ret; 35ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown struct sigaction sa; 36ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 37ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown sa.sa_handler = handler; 38ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown sigfillset(&sa.sa_mask); 39ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown sa.sa_flags = SA_RESTART; 40ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 41ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown sigaction(SIGUSR1, &sa, NULL); 42ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 43ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown close(fds[1]); 44ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown ret = read(fds[0], &ch, 1); 45ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 46ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown if (ret != 1 || ch != 'x') 47ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown fprintf(stderr, "FAIL: expected 1 byte, not %d/%s/%c\n", 48ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown ret, strerror(errno), ch); 49ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown } else { 50ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown signal(SIGPIPE, SIG_IGN); 51ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 52ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown close(fds[0]); 53ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown sleep(1); 54ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown kill(pid, SIGUSR1); 55ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown sleep(1); 56ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown write(fds[1], "x", 1); 57ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 58ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown waitpid(pid, NULL, 0); 59ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown } 60ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown 61ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown return 0; 62ed07e00d438c74b7a23c01bfffde77e3968305e4Jeff Brown} 63