From a71e42c461da1672582143a829654049399616e7 Mon Sep 17 00:00:00 2001
From: Judd Vinet <judd@archlinux.org>
Date: Sun, 21 Dec 2003 00:48:23 +0000
Subject: upgpkg: initscripts 0.6

---
 minilogd.c | 184 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 184 insertions(+)
 create mode 100644 minilogd.c

(limited to 'minilogd.c')

diff --git a/minilogd.c b/minilogd.c
new file mode 100644
index 0000000..76e4a9c
--- /dev/null
+++ b/minilogd.c
@@ -0,0 +1,184 @@
+
+/* minilogd.c
+ * 
+ * A pale imitation of syslogd. Most notably, doesn't write anything
+ * anywhere except possibly back to syslogd.
+ * 
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <unistd.h>
+
+#include <sys/poll.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/un.h>
+
+static int we_own_log=0;
+static char **buffer=NULL;
+static int buflines=0;
+
+int debug;
+
+int recvsock;
+
+void alarm_handler(int x) {
+	alarm(0);
+	close(recvsock);
+	recvsock = -1;
+}
+
+void freeBuffer() {
+	struct sockaddr_un addr;
+	int sock;
+	int x=0,conn;
+
+	bzero(&addr,sizeof(addr));
+	addr.sun_family = AF_LOCAL;
+	strncpy(addr.sun_path,_PATH_LOG,sizeof(addr.sun_path)-1);
+	/* wait for klogd to hit syslog */
+	sleep(2);
+	sock = socket(AF_LOCAL, SOCK_DGRAM,0);
+	conn=connect(sock,(struct sockaddr *) &addr,sizeof(addr));
+	while (x<buflines) {
+		if (!conn) {
+			/*printf("to syslog: %s\n", buffer[x]);*/
+			write(sock,buffer[x],strlen(buffer[x])+1);
+		}
+		free(buffer[x]);
+		x++;
+	}
+}
+
+void cleanup(int exitcode) {
+	/* If we own the log, unlink it before trying to free our buffer.
+	 * Otherwise, sending the buffer to /dev/log doesn't make much sense.... */
+	if (we_own_log) {
+		perror("wol");
+		unlink(_PATH_LOG);
+	}
+	/* Don't try to free buffer if we were called from a signal handler */
+	if (exitcode<=0) {
+		if (buffer) freeBuffer();
+		exit(exitcode);
+	} else
+		exit(exitcode+128);
+}
+
+void runDaemon(int sock) {
+	struct sockaddr_un addr;
+	int x,len,addrlen,done=0;
+	char *message;
+	struct stat s1,s2;
+	struct pollfd pfds;
+
+	daemon(0,-1);
+	/* try not to leave stale sockets lying around */
+	/* Hopefully, we won't actually get any of these */
+	signal(SIGHUP,cleanup);
+	signal(SIGINT,cleanup);
+	signal(SIGQUIT,cleanup);
+	signal(SIGILL,cleanup);
+	signal(SIGABRT,cleanup);
+	signal(SIGFPE,cleanup);
+	signal(SIGSEGV,cleanup);
+	signal(SIGPIPE,cleanup);
+	signal(SIGBUS,cleanup);
+	signal(SIGTERM,cleanup);
+	done = 0;
+	/* Get stat info on /dev/log so we can later check to make sure we
+	 * still own it... */
+	if (stat(_PATH_LOG,&s1) != 0)
+		memset(&s1, '\0', sizeof(struct stat));
+	while (!done) {
+		pfds.fd = sock;
+		pfds.events = POLLIN|POLLPRI;
+		if ( ( (x=poll(&pfds,1,500))==-1) && errno !=EINTR) {
+			perror("poll");
+			cleanup(-1);
+		}
+		if ( (x>0) && pfds.revents & (POLLIN | POLLPRI)) {
+			message = calloc(8192,sizeof(char));
+			recvsock = accept(sock,(struct sockaddr *) &addr, &addrlen);
+			alarm(2);
+			signal(SIGALRM, alarm_handler);
+			len = read(recvsock,message,8192);
+			alarm(0);
+			close(recvsock);
+			if (len>0) {
+				/*printf("line recv'd: %s\n", message);*/
+				if (buflines < 200000) {
+					if (buffer)
+						buffer = realloc(buffer,(buflines+1)*sizeof(char *));
+					else
+						buffer = malloc(sizeof(char *));
+					message[strlen(message)]='\n';
+					buffer[buflines]=message;
+					buflines++;
+				}
+			}
+			else {
+				recvsock=-1;
+			}
+		}
+		if ( (x>0) && ( pfds.revents & (POLLHUP | POLLNVAL)) )
+			done = 1;
+		/* Check to see if syslogd's yanked our socket out from under us */
+		if ( (stat(_PATH_LOG,&s2)!=0) ||
+				(s1.st_ino != s2.st_ino ) || (s1.st_ctime != s2.st_ctime) ||
+				(s1.st_mtime != s2.st_mtime) ) { /*|| (s1.st_atime != s2.st_atime) ) {*/
+			done = 1;
+			we_own_log = 0;
+			/*printf("someone stole our %s\n", _PATH_LOG);
+			printf("st_ino:   %d %d\n", s1.st_ino, s2.st_ino);
+			printf("st_ctime: %d %d\n", s1.st_ctime, s2.st_ctime);
+			printf("st_atime: %d %d\n", s1.st_atime, s2.st_atime);
+			printf("st_mtime: %d %d\n", s1.st_mtime, s2.st_mtime);*/
+		}
+	}
+	cleanup(0);
+}
+
+int main(int argc, char **argv) {
+	struct sockaddr_un addr;
+	int sock;
+	int pid;
+
+	/* option processing made simple... */
+	if (argc>1) debug=1;
+	/* just in case */
+	sock = open("/dev/null",O_RDWR);
+	dup2(sock,0);
+	dup2(sock,1);
+	dup2(sock,2);
+
+	bzero(&addr, sizeof(addr));
+	addr.sun_family = AF_LOCAL;
+	strncpy(addr.sun_path,_PATH_LOG,sizeof(addr.sun_path)-1);
+	sock = socket(AF_LOCAL, SOCK_STREAM,0);
+	unlink(_PATH_LOG);
+	/* Bind socket before forking, so we know if the server started */
+	if (!bind(sock,(struct sockaddr *) &addr, sizeof(addr))) {
+		we_own_log = 1;
+		listen(sock,5);
+		if ((pid=fork())==-1) {
+			perror("fork");
+			exit(3);
+		}
+		if (pid) {
+			exit(0);
+		} else {
+			/*printf("starting daemon...\n");*/
+			runDaemon(sock);
+			/* shouldn't get back here... */
+			exit(4);
+		}
+	} else {
+		exit(5);
+	}
+}
-- 
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