1 files changed, 89 insertions, 0 deletions
diff --git a/src/util/fifo_rdwr_bug.c b/src/util/fifo_rdwr_bug.c
new file mode 100644
index 0000000..2486876
--- /dev/null
+++ b/src/util/fifo_rdwr_bug.c
@@ -0,0 +1,89 @@
+/*++
+/* NAME
+/*	fifo_rdwr_bug 1
+/* SUMMARY
+/*	fifo server test program
+/* SYNOPSIS
+/*	fifo_rdwr_bug
+/* DESCRIPTION
+/*	fifo_rdwr_bug creates a FIFO and opens it read-write mode.
+/*	On BSD/OS 3.1 select() will report that the FIFO is readable
+/*	even before any data is written to it. Doing an actual read
+/*	causes the read to block; a non-blocking read fails.
+/* DIAGNOSTICS
+/*	Problems are reported to the standard error stream.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+#include <sys_defs.h>
+#include <sys/time.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define FIFO_PATH       "test-fifo"
+#define perrorexit(s)   { perror(s); exit(1); }
+
+static void cleanup(void)
+{
+    printf("Removing fifo %s...\n", FIFO_PATH);
+    if (unlink(FIFO_PATH))
+	perrorexit("unlink");
+    printf("Done.\n");
+}
+
+int     main(int unused_argc, char **unused_argv)
+{
+    struct timeval tv;
+    fd_set  read_fds;
+    fd_set  except_fds;
+    int     fd;
+
+    (void) unlink(FIFO_PATH);
+
+    printf("Creating fifo %s...\n", FIFO_PATH);
+    if (mkfifo(FIFO_PATH, 0600) < 0)
+	perrorexit("mkfifo");
+
+    printf("Opening fifo %s, read-write mode...\n", FIFO_PATH);
+    if ((fd = open(FIFO_PATH, O_RDWR, 0)) < 0) {
+	perror("open");
+	cleanup();
+	exit(1);
+    }
+    printf("Selecting the fifo for readability...\n");
+    FD_ZERO(&read_fds);
+    FD_SET(fd, &read_fds);
+    FD_ZERO(&except_fds);
+    FD_SET(fd, &except_fds);
+    tv.tv_sec = 1;
+    tv.tv_usec = 0;
+
+    switch (select(fd + 1, &read_fds, (fd_set *) 0, &except_fds, &tv)) {
+    case -1:
+	perrorexit("select");
+    default:
+	if (FD_ISSET(fd, &read_fds)) {
+	    printf("Opening a fifo read-write makes it readable!!\n");
+	    break;
+	}
+    case 0:
+	printf("The fifo is not readable, as it should be.\n");
+	break;
+    }
+    cleanup();
+    exit(0);
+}