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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-15 18:02:34 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-15 18:02:34 +0000
commitfadeddfbb2aa38a980dd959b5ec1ffba7afd43cb (patch)
treea7bde6111c84ea64619656a38fba50909fa0bf60 /libevent/sample/event-read-fifo.c
parentInitial commit. (diff)
downloadlldpd-upstream.tar.xz
lldpd-upstream.zip
Adding upstream version 1.0.18.upstream/1.0.18upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--libevent/sample/event-read-fifo.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/libevent/sample/event-read-fifo.c b/libevent/sample/event-read-fifo.c
new file mode 100644
index 0000000..a17b9bd
--- /dev/null
+++ b/libevent/sample/event-read-fifo.c
@@ -0,0 +1,162 @@
+/*
+ * This sample code shows how to use Libevent to read from a named pipe.
+ * XXX This code could make better use of the Libevent interfaces.
+ *
+ * XXX This does not work on Windows; ignore everything inside the _WIN32 block.
+ *
+ * On UNIX, compile with:
+ * cc -I/usr/local/include -o event-read-fifo event-read-fifo.c \
+ * -L/usr/local/lib -levent
+ */
+
+#include <event2/event-config.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#ifndef _WIN32
+#include <sys/queue.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <signal.h>
+#else
+#include <winsock2.h>
+#include <windows.h>
+#endif
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include <event2/event.h>
+
+static void
+fifo_read(evutil_socket_t fd, short event, void *arg)
+{
+ char buf[255];
+ int len;
+ struct event *ev = arg;
+#ifdef _WIN32
+ DWORD dwBytesRead;
+#endif
+
+ fprintf(stderr, "fifo_read called with fd: %d, event: %d, arg: %p\n",
+ (int)fd, event, arg);
+#ifdef _WIN32
+ len = ReadFile((HANDLE)fd, buf, sizeof(buf) - 1, &dwBytesRead, NULL);
+
+ /* Check for end of file. */
+ if (len && dwBytesRead == 0) {
+ fprintf(stderr, "End Of File");
+ event_del(ev);
+ return;
+ }
+
+ buf[dwBytesRead] = '\0';
+#else
+ len = read(fd, buf, sizeof(buf) - 1);
+
+ if (len <= 0) {
+ if (len == -1)
+ perror("read");
+ else if (len == 0)
+ fprintf(stderr, "Connection closed\n");
+ event_del(ev);
+ event_base_loopbreak(event_get_base(ev));
+ return;
+ }
+
+ buf[len] = '\0';
+#endif
+ fprintf(stdout, "Read: %s\n", buf);
+}
+
+/* On Unix, cleanup event.fifo if SIGINT is received. */
+#ifndef _WIN32
+static void
+signal_cb(evutil_socket_t fd, short event, void *arg)
+{
+ struct event_base *base = arg;
+ event_base_loopbreak(base);
+}
+#endif
+
+int
+main(int argc, char **argv)
+{
+ struct event *evfifo;
+ struct event_base* base;
+#ifdef _WIN32
+ HANDLE socket;
+ /* Open a file. */
+ socket = CreateFileA("test.txt", /* open File */
+ GENERIC_READ, /* open for reading */
+ 0, /* do not share */
+ NULL, /* no security */
+ OPEN_EXISTING, /* existing file only */
+ FILE_ATTRIBUTE_NORMAL, /* normal file */
+ NULL); /* no attr. template */
+
+ if (socket == INVALID_HANDLE_VALUE)
+ return 1;
+
+#else
+ struct event *signal_int;
+ struct stat st;
+ const char *fifo = "event.fifo";
+ int socket;
+
+ if (lstat(fifo, &st) == 0) {
+ if ((st.st_mode & S_IFMT) == S_IFREG) {
+ errno = EEXIST;
+ perror("lstat");
+ exit(1);
+ }
+ }
+
+ unlink(fifo);
+ if (mkfifo(fifo, 0600) == -1) {
+ perror("mkfifo");
+ exit(1);
+ }
+
+ socket = open(fifo, O_RDONLY | O_NONBLOCK, 0);
+
+ if (socket == -1) {
+ perror("open");
+ exit(1);
+ }
+
+ fprintf(stderr, "Write data to %s\n", fifo);
+#endif
+ /* Initialize the event library */
+ base = event_base_new();
+
+ /* Initialize one event */
+#ifdef _WIN32
+ evfifo = event_new(base, (evutil_socket_t)socket, EV_READ|EV_PERSIST, fifo_read,
+ event_self_cbarg());
+#else
+ /* catch SIGINT so that event.fifo can be cleaned up */
+ signal_int = evsignal_new(base, SIGINT, signal_cb, base);
+ event_add(signal_int, NULL);
+
+ evfifo = event_new(base, socket, EV_READ|EV_PERSIST, fifo_read,
+ event_self_cbarg());
+#endif
+
+ /* Add it to the active events, without a timeout */
+ event_add(evfifo, NULL);
+
+ event_base_dispatch(base);
+ event_base_free(base);
+#ifdef _WIN32
+ CloseHandle(socket);
+#else
+ close(socket);
+ unlink(fifo);
+#endif
+ libevent_global_shutdown();
+ return (0);
+}
+