add new syslog-listen program to repository

1 files changed, 47 insertions, 0 deletions

diff --git a/small-codes/syslog-listen.c b/small-codes/syslog-listen.c
new file mode 100644
index 0000000..c878076
--- /dev/null
+++ b/small-codes/syslog-listen.c
@@ -0,0 +1,47 @@
+// This program is able to listen to a datagram unix socket displaying
+// a linefeed at each receive. Useful when other program wants scrutinize
+// syslog forwarded outputs for example (like in omuxsock module by rsyslog
+// does).
+//
+// compile with gcc/clang -o syslog-listen syslog-listen.c
+
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <errno.h>
+
+#define PERROR(code, msg) { if ((code) == -1) { perror((msg)); exit(1); } }
+
+int main(int argc, const char** argv)
+{
+    if (argc < 2) {
+        fprintf(stderr, "Usage: syslog-listen </path>\n");
+        exit(1);
+    }
+
+    struct sockaddr_un sock_file;
+    memset(&sock_file, 0, sizeof(sock_file));
+    sock_file.sun_family = AF_UNIX;
+    strncpy(sock_file.sun_path, argv[1], sizeof(sock_file.sun_path));
+
+    int sock = socket(AF_UNIX, SOCK_DGRAM, 0);
+    PERROR(sock, "socket");
+    unlink(argv[1]); // no need to test ret as bind will crash if needed
+    int ret = bind(sock, (struct sockaddr*)&sock_file, sizeof(sock_file));
+    PERROR(ret, "bind");
+
+    char buf[8192];
+    int receive;
+    while (1) {
+        receive = recv(sock, buf, sizeof(buf), 0);
+        PERROR(receive, "recv");
+        buf[receive] = '\0';
+        printf("received: %s\n", buf);
+    }
+
+    return 0;
+}