diff options
| author | Mark Whitley | 2001-03-12 22:51:50 +0000 |
|---|---|---|
| committer | Mark Whitley | 2001-03-12 22:51:50 +0000 |
| commit | 6317c4baf79c25d7f77897b064eb4f0b7d9f070e (patch) | |
| tree | 5fc8fe65a4903f6224925a72b53a4f46e2b0b1d3 /sysklogd/logread.c | |
| parent | 4987bbf97924044c88007c45ee2674d97b93ad92 (diff) | |
| download | busybox-6317c4baf79c25d7f77897b064eb4f0b7d9f070e.zip busybox-6317c4baf79c25d7f77897b064eb4f0b7d9f070e.tar.gz | |
Applied patch from Gennady Feldman to split up syslogd.c into syslogd and
klogd (as it should be).
Diffstat (limited to 'sysklogd/logread.c')
| -rw-r--r-- | sysklogd/logread.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/sysklogd/logread.c b/sysklogd/logread.c new file mode 100644 index 0000000..3bf4c54 --- /dev/null +++ b/sysklogd/logread.c @@ -0,0 +1,135 @@ +/* vi: set sw=4 ts=4: */
+/*
+ * circular buffer syslog implementation for busybox
+ *
+ * Copyright (C) 2000 by Gennady Feldman <gfeldman@cachier.com>
+ *
+ * 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"
+
+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 shmid = -1; // ipc shared memory id
+static int 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 ( (shmid = shmget(KEY_ID, 0, 0)) == -1)
+ error_exit("Can't find circular buffer");
+
+ // Attach shared memory to our char*
+ if ( (buf = shmat(shmid, NULL, SHM_RDONLY)) == NULL)
+ error_exit("Can't get access to circular buffer from syslogd");
+
+ if ( (semid = semget(KEY_ID, 0, 0)) == -1)
+ error_exit("Can't get access to semaphone(s) for circular buffer from syslogd");
+
+ sem_down(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(semid);
+
+output_end:
+ if (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 (shmid != -1)
+ shmdt(buf);
+
+ exit(1);
+}
+
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