Race less.

diff --git a/regress/sys/fifofs/fifotest.c b/regress/sys/fifofs/fifotest.c
index 87c1332..ee31630 100644 (file)
--- a/regress/sys/fifofs/fifotest.c
+++ b/regress/sys/fifofs/fifotest.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2014 Todd C. Miller <Todd.Miller@courtesan.com>
+ * Copyright (c) 2004, 2014-2015 Todd C. Miller <Todd.Miller@courtesan.com>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -32,8 +32,9 @@
 
 void usage(void);
 void sigalrm(int);
-void dopoll(int, int, char *, int);
-void doselect(int, int, int);
+void sigusr1(int);
+void dopoll(pid_t, int, int, char *, int);
+void doselect(pid_t, int, int, int);
 void runtest(char *, int, int);
 void eoftest(char *, int, int);
 
@@ -58,12 +59,17 @@ main(int argc, char **argv)
        if (argc != 2)
                usage();
 
-       /* Just warn EINTR from SIGALRM */
+       /* Just want EINTR from SIGALRM */
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = 0;
        sa.sa_handler = sigalrm;
        sigaction(SIGALRM, &sa, NULL);
 
+       /* SIGUSR1 is used for syncronization only. */
+       sa.sa_flags = SA_RESTART;
+       sa.sa_handler = sigusr1;
+       sigaction(SIGUSR1, &sa, NULL);
+
        runtest(argv[1], 0, 0);
        runtest(argv[1], 0, INFTIM);
        runtest(argv[1], O_NONBLOCK, 0);
@@ -86,6 +92,7 @@ runtest(char *fifo, int flags, int timeout)
                exit(1);
        }
 
+       /* Note: O_RDWR not required by POSIX */
        alarm(2);
        if ((fd = open(fifo, O_RDWR | flags, 0644)) == -1) {
                printf("open %s: %s\n", fifo, strerror(errno));
@@ -97,14 +104,14 @@ runtest(char *fifo, int flags, int timeout)
            (flags & O_NONBLOCK) ? " (nonblocking)" : "");
 
        printf("\nTesting empty FIFO:\n");
-       dopoll(fd, POLLIN|POLLOUT, "POLLIN|POLLOUT", timeout);
-       dopoll(fd, POLLIN, "POLLIN", timeout);
-       dopoll(fd, POLLOUT, "POLLOUT", timeout);
-       dopoll(fd, 0, "(none)", timeout);
-       doselect(fd, fd, timeout);
-       doselect(fd, -1, timeout);
-       doselect(-1, fd, timeout);
-       doselect(-1, -1, timeout);
+       dopoll(-1, fd, POLLIN|POLLOUT, "POLLIN|POLLOUT", timeout);
+       dopoll(-1, fd, POLLIN, "POLLIN", timeout);
+       dopoll(-1, fd, POLLOUT, "POLLOUT", timeout);
+       dopoll(-1, fd, 0, "(none)", timeout);
+       doselect(-1, fd, fd, timeout);
+       doselect(-1, fd, -1, timeout);
+       doselect(-1, -1, fd, timeout);
+       doselect(-1, -1, -1, timeout);
 
        if (write(fd, "test", 4) != 4) {
                printf("write error: %s\n", strerror(errno));
@@ -112,14 +119,14 @@ runtest(char *fifo, int flags, int timeout)
        }
 
        printf("\nTesting full FIFO:\n");
-       dopoll(fd, POLLIN|POLLOUT, "POLLIN|POLLOUT", timeout);
-       dopoll(fd, POLLIN, "POLLIN", timeout);
-       dopoll(fd, POLLOUT, "POLLOUT", timeout);
-       dopoll(fd, 0, "(none)", timeout);
-       doselect(fd, fd, timeout);
-       doselect(fd, -1, timeout);
-       doselect(-1, fd, timeout);
-       doselect(-1, -1, timeout);
+       dopoll(-1, fd, POLLIN|POLLOUT, "POLLIN|POLLOUT", timeout);
+       dopoll(-1, fd, POLLIN, "POLLIN", timeout);
+       dopoll(-1, fd, POLLOUT, "POLLOUT", timeout);
+       dopoll(-1, fd, 0, "(none)", timeout);
+       doselect(-1, fd, fd, timeout);
+       doselect(-1, fd, -1, timeout);
+       doselect(-1, -1, fd, timeout);
+       doselect(-1, -1, -1, timeout);
 
        if ((nread = read(fd, buf, sizeof(buf))) <= 0) {
                printf("read error: %s\n", (nread == 0) ? "EOF" : strerror(errno));
@@ -129,12 +136,19 @@ runtest(char *fifo, int flags, int timeout)
        printf("\treceived '%s' from FIFO\n", buf);
 }
 
-int
+pid_t
 eof_writer(const char *fifo, int flags)
 {
        int fd;
+       pid_t pid;
+       sigset_t mask, omask;
 
-       switch (fork()) {
+       /* Block SIGUSR1 (in child). */
+       sigemptyset(&mask);
+       sigaddset(&mask, SIGUSR1);
+       sigprocmask(SIG_BLOCK, &mask, &omask);
+
+       switch ((pid = fork())) {
        case -1:
                printf("fork: %s\n", strerror(errno));
                return -1;
@@ -143,26 +157,27 @@ eof_writer(const char *fifo, int flags)
                break;
        default:
                /* parent */
-               return 0;
+               sigprocmask(SIG_SETMASK, &omask, NULL);
+               return pid;
        }
 
-       /* Wait for the reader to connect. */
-       for (;;) {
-               alarm(2);
-               fd = open(fifo, O_WRONLY | flags, 0644);
-               alarm(0);
-               if (fd != -1)
-                       break;
-               if (errno != ENOENT && errno != ENXIO) {
-                       printf("open %s O_WRONLY: %s\n", fifo, strerror(errno));
-                       return -1;
-               }
-               usleep(10000);
+       /* Wait for reader. */
+       sigemptyset(&mask);
+       sigsuspend(&mask);
+       sigprocmask(SIG_SETMASK, &omask, NULL);
+
+       /* connect to FIFO. */
+       alarm(2);
+       fd = open(fifo, O_WRONLY | flags, 0644);
+       alarm(0);
+       if (fd == -1) {
+               printf("open %s O_WRONLY: %s\n", fifo, strerror(errno));
+               return -1;
        }
 
        /*
-        * We need to give the reader time to call select() before
-        * we close the fd.  This is racey...
+        * We need to give the reader time to call poll() or select()
+        * before we close the fd.  This is racey...
         */
        usleep(100000);
        close(fd);
@@ -173,7 +188,8 @@ void
 eoftest(char *fifo, int flags, int timeout)
 {
        ssize_t nread;
-       int fd = -1, rval, pass, status;
+       int fd = -1, pass, status;
+       pid_t writer;
        char buf[BUFSIZ];
 
        /*
@@ -211,42 +227,42 @@ eoftest(char *fifo, int flags, int timeout)
                 * The writer will sleep for a bit to give the reader time
                 * to call select() before anything has been written.
                 */
-               rval = eof_writer(fifo, flags);
-               if (rval == -1)
+               writer = eof_writer(fifo, flags);
+               if (writer == -1)
                        exit(1);
 
                switch (pass) {
                case 0:
                case 1:
-                   dopoll(fd, POLLIN|POLLOUT, "POLLIN|POLLOUT", timeout);
+                   dopoll(writer, fd, POLLIN|POLLOUT, "POLLIN|POLLOUT", timeout);
                    break;
                case 2:
                case 3:
-                   dopoll(fd, POLLIN, "POLLIN", timeout);
+                   dopoll(writer, fd, POLLIN, "POLLIN", timeout);
                    break;
                case 4:
                case 5:
-                   dopoll(fd, POLLOUT, "POLLOUT", timeout);
+                   dopoll(writer, fd, POLLOUT, "POLLOUT", timeout);
                    break;
                case 6:
                case 7:
-                   dopoll(fd, 0, "(none)", timeout);
+                   dopoll(writer, fd, 0, "(none)", timeout);
                    break;
                case 8:
                case 9:
-                   doselect(fd, fd, timeout);
+                   doselect(writer, fd, fd, timeout);
                    break;
                case 10:
                case 11:
-                   doselect(fd, -1, timeout);
+                   doselect(writer, fd, -1, timeout);
                    break;
                case 12:
                case 13:
-                   doselect(-1, fd, timeout);
+                   doselect(writer, -1, fd, timeout);
                    break;
                case 14:
                case 15:
-                   doselect(-1, -1, timeout);
+                   doselect(writer, -1, -1, timeout);
                    break;
                }
                wait(&status);
@@ -263,7 +279,7 @@ eoftest(char *fifo, int flags, int timeout)
 }
 
 void
-dopoll(int fd, int events, char *str, int timeout)
+dopoll(pid_t writer, int fd, int events, char *str, int timeout)
 {
        struct pollfd pfd;
        int nready;
@@ -273,6 +289,8 @@ dopoll(int fd, int events, char *str, int timeout)
 
        printf("\tpoll %s, timeout=%d\n", str, timeout);
        pfd.events = events;
+       if (writer != -1)
+               kill(writer, SIGUSR1);
        alarm(2);
        nready = poll(&pfd, 1, timeout);
        alarm(0);
@@ -295,7 +313,7 @@ dopoll(int fd, int events, char *str, int timeout)
 }
 
 void
-doselect(int rfd, int wfd, int timeout)
+doselect(pid_t writer, int rfd, int wfd, int timeout)
 {
        struct timeval tv, *tvp;
        fd_set *rfds = NULL, *wfds = NULL;
@@ -329,7 +347,8 @@ doselect(int rfd, int wfd, int timeout)
 
        printf("\tselect%s%s, timeout=%d\n", rfds ? " read" : "",
            wfds ? " write" : rfds ? "" : " (none)", timeout);
-
+       if (writer != -1)
+               kill(writer, SIGUSR1);
        alarm(2);
        nready = select(maxfd + 1, rfds, wfds, NULL, &tv);
        alarm(0);
@@ -355,6 +374,12 @@ sigalrm(int dummy)
        return;
 }
 
+void
+sigusr1(int dummy)
+{
+       return;
+}
+
 void
 usage(void)
 {