1 files changed, 144 insertions, 0 deletions
diff --git a/release/src/router/busybox/logread.c b/release/src/router/busybox/logread.c
new file mode 100644
index 00000000..d3349625
--- /dev/null
+++ b/release/src/router/busybox/logread.c
@@ -0,0 +1,144 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * circular buffer syslog implementation for busybox
+ *
+ * Copyright (C) 2000 by Gennady Feldman <gfeldman@cachier.com>
+ *
+ * Maintainer: Gennady Feldman <gena01@cachier.com> as of Mar 12, 2001
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307 USA
+ *
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ipc.h>
+#include <sys/types.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+#include <signal.h>
+#include <setjmp.h>
+#include "busybox.h"
+
+#if __GNU_LIBRARY__ < 5
+#error Sorry.  Looks like you are using libc5.  
+#error libc5 shm support isnt good enough.
+#error Please disable BB_FEATURE_IPC_SYSLOG 
+#endif	
+
+
+static const long KEY_ID = 0x414e4547; /*"GENA"*/
+
+static struct shbuf_ds {
+	int size;		// size of data written
+	int head;		// start of message list
+	int tail;		// end of message list
+	char data[1];		// data/messages
+} *buf = NULL;			// shared memory pointer
+
+
+// Semaphore operation structures
+static struct sembuf SMrup[1] = {{0, -1, IPC_NOWAIT | SEM_UNDO}}; // set SMrup
+static struct sembuf SMrdn[2] = {{1, 0}, {0, +1, SEM_UNDO}}; // set SMrdn
+
+static int	log_shmid = -1;	// ipc shared memory id
+static int	log_semid = -1;	// ipc semaphore id
+static jmp_buf	jmp_env;
+
+static void error_exit(const char *str);
+static void interrupted(int sig);
+
+/*
+ * sem_up - up()'s a semaphore.
+ */
+static inline void sem_up(int semid)
+{
+	if ( semop(semid, SMrup, 1) == -1 ) 
+		error_exit("semop[SMrup]");
+}
+
+/*
+ * sem_down - down()'s a semaphore
+ */				
+static inline void sem_down(int semid)
+{
+	if ( semop(semid, SMrdn, 2) == -1 )
+		error_exit("semop[SMrdn]");
+}
+
+extern int logread_main(int argc, char **argv)
+{
+	int i;
+	
+	/* no options, no getopt */
+	if (argc > 1)
+		show_usage();
+	
+	// handle intrrupt signal
+	if (setjmp(jmp_env)) goto output_end;
+	
+	// attempt to redefine ^C signal
+	signal(SIGINT, interrupted);
+	
+	if ( (log_shmid = shmget(KEY_ID, 0, 0)) == -1)
+		error_exit("Can't find circular buffer");
+	
+	// Attach shared memory to our char*
+	if ( (buf = shmat(log_shmid, NULL, SHM_RDONLY)) == NULL)
+		error_exit("Can't get access to circular buffer from syslogd");
+
+	if ( (log_semid = semget(KEY_ID, 0, 0)) == -1)
+	    	error_exit("Can't get access to semaphone(s) for circular buffer from syslogd");
+
+	sem_down(log_semid);	
+	// Read Memory 
+	i=buf->head;
+
+	//printf("head: %i tail: %i size: %i\n",buf->head,buf->tail,buf->size);
+	if (buf->head == buf->tail) {
+		printf("<empty syslog>\n");
+	}
+	
+	while ( i != buf->tail) {
+		printf("%s", buf->data+i);
+		i+= strlen(buf->data+i) + 1;
+		if (i >= buf->size )
+			i=0;
+	}
+	sem_up(log_semid);
+
+output_end:
+	if (log_shmid != -1) 
+		shmdt(buf);
+		
+	return EXIT_SUCCESS;		
+}
+
+static void interrupted(int sig){
+	signal(SIGINT, SIG_IGN);
+	longjmp(jmp_env, 1);
+}
+
+static void error_exit(const char *str){
+	perror(str);
+	//release all acquired resources
+	if (log_shmid != -1) 
+		shmdt(buf);
+
+	exit(1);
+}