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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 12:06:34 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 12:06:34 +0000
commit5e61585d76ae77fd5e9e96ebabb57afa4d74880d (patch)
tree2b467823aaeebc7ef8bc9e3cabe8074eaef1666d /src/util/select_bug.c
parentInitial commit. (diff)
downloadpostfix-5e61585d76ae77fd5e9e96ebabb57afa4d74880d.tar.xz
postfix-5e61585d76ae77fd5e9e96ebabb57afa4d74880d.zip
Adding upstream version 3.5.24.upstream/3.5.24upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/util/select_bug.c')
-rw-r--r--src/util/select_bug.c95
1 files changed, 95 insertions, 0 deletions
diff --git a/src/util/select_bug.c b/src/util/select_bug.c
new file mode 100644
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--- /dev/null
+++ b/src/util/select_bug.c
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+/*++
+/* NAME
+/* select_bug 1
+/* SUMMARY
+/* select test program
+/* SYNOPSIS
+/* select_bug
+/* DESCRIPTION
+/* select_bug forks child processes that perform select()
+/* on a shared socket, and sees if a wakeup affects other
+/* processes selecting on a different socket or stdin.
+/* 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
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h> /* bzero() prototype for 44BSD */
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstream.h>
+#include <msg_vstream.h>
+
+static pid_t fork_and_read_select(const char *what, int delay, int fd)
+{
+ struct timeval tv;
+ pid_t pid;
+ fd_set readfds;
+
+ switch (pid = fork()) {
+ case -1:
+ msg_fatal("fork: %m");
+ case 0:
+ tv.tv_sec = delay;
+ tv.tv_usec = 0;
+ FD_ZERO(&readfds);
+ FD_SET(fd, &readfds);
+ switch (select(fd + 1, &readfds, (fd_set *) 0, &readfds, &tv)) {
+ case -1:
+ msg_fatal("select: %m");
+ case 0:
+ msg_info("%s select timed out", what);
+ exit(0);
+ default:
+ msg_info("%s select wakeup", what);
+ exit(0);
+ }
+ default:
+ return (pid);
+ }
+}
+
+int main(int argc, char **argv)
+{
+ int pair1[2];
+ int pair2[2];
+
+ msg_vstream_init(argv[0], VSTREAM_ERR);
+
+#define DELAY 1
+
+ if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair1) < 0)
+ msg_fatal("socketpair: %m");
+ if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair2) < 0)
+ msg_fatal("socketpair: %m");
+
+ vstream_printf("Doing multiple select on socket1, then write to it...\n");
+ vstream_fflush(VSTREAM_OUT);
+ fork_and_read_select("socket1", DELAY, pair1[0]); /* one */
+ fork_and_read_select("socket1", DELAY, pair1[0]); /* two */
+ fork_and_read_select("socket2", DELAY, pair2[0]);
+ fork_and_read_select("stdin", DELAY, 0);
+ if (write(pair1[1], "", 1) != 1)
+ msg_fatal("write: %m");
+ while (wait((int *) 0) >= 0)
+ /* void */ ;
+ return (0);
+}