-/* vi: set sw=4 ts=4: */\r
-/*\r
- * circular buffer syslog implementation for busybox\r
- *\r
- * Copyright (C) 2000 by Gennady Feldman <gfeldman@cachier.com>\r
- *\r
- * This program is free software; you can redistribute it and/or modify\r
- * it under the terms of the GNU General Public License as published by\r
- * the Free Software Foundation; either version 2 of the License, or\r
- * (at your option) any later version.\r
- *\r
- * This program is distributed in the hope that it will be useful,\r
- * but WITHOUT ANY WARRANTY; without even the implied warranty of\r
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU\r
- * General Public License for more details.\r
- *\r
- * You should have received a copy of the GNU General Public License\r
- * along with this program; if not, write to the Free Software\r
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA\r
- * 02111-1307 USA\r
- *\r
- */\r
-\r
-#include <stdio.h>\r
-#include <stdlib.h>\r
-#include <string.h>\r
-#include <sys/ipc.h>\r
-#include <sys/types.h>\r
-#include <sys/sem.h>\r
-#include <sys/shm.h>\r
-#include <signal.h>\r
-#include <setjmp.h>\r
-#include "busybox.h"\r
-\r
-static const long KEY_ID = 0x414e4547; /*"GENA"*/\r
-\r
-static struct shbuf_ds {\r
- int size; // size of data written\r
- int head; // start of message list\r
- int tail; // end of message list\r
- char data[1]; // data/messages\r
-} *buf = NULL; // shared memory pointer\r
-\r
-\r
-// Semaphore operation structures\r
-static struct sembuf SMrup[1] = {{0, -1, IPC_NOWAIT | SEM_UNDO}}; // set SMrup\r
-static struct sembuf SMrdn[2] = {{1, 0}, {0, +1, SEM_UNDO}}; // set SMrdn\r
-\r
-static int shmid = -1; // ipc shared memory id\r
-static int semid = -1; // ipc semaphore id\r
-static jmp_buf jmp_env;\r
-\r
-static void error_exit(const char *str);\r
-static void interrupted(int sig);\r
-\r
-/*\r
- * sem_up - up()'s a semaphore.\r
- */\r
-static inline void sem_up(int semid)\r
-{\r
- if ( semop(semid, SMrup, 1) == -1 ) \r
- error_exit("semop[SMrup]");\r
-}\r
-\r
-/*\r
- * sem_down - down()'s a semaphore\r
- */ \r
-static inline void sem_down(int semid)\r
-{\r
- if ( semop(semid, SMrdn, 2) == -1 )\r
- error_exit("semop[SMrdn]");\r
-}\r
-\r
-extern int logread_main(int argc, char **argv)\r
-{\r
- int i;\r
- \r
- /* no options, no getopt */\r
- if (argc > 1)\r
- show_usage();\r
- \r
- // handle intrrupt signal\r
- if (setjmp(jmp_env)) goto output_end;\r
- \r
- // attempt to redefine ^C signal\r
- signal(SIGINT, interrupted);\r
- \r
- if ( (shmid = shmget(KEY_ID, 0, 0)) == -1)\r
- error_exit("Can't find circular buffer");\r
- \r
- // Attach shared memory to our char*\r
- if ( (buf = shmat(shmid, NULL, SHM_RDONLY)) == NULL)\r
- error_exit("Can't get access to circular buffer from syslogd");\r
-\r
- if ( (semid = semget(KEY_ID, 0, 0)) == -1)\r
- error_exit("Can't get access to semaphone(s) for circular buffer from syslogd");\r
-\r
- sem_down(semid); \r
- // Read Memory \r
- i=buf->head;\r
-\r
- //printf("head: %i tail: %i size: %i\n",buf->head,buf->tail,buf->size);\r
- if (buf->head == buf->tail) {\r
- printf("<empty syslog>\n");\r
- }\r
- \r
- while ( i != buf->tail) {\r
- printf("%s", buf->data+i);\r
- i+= strlen(buf->data+i) + 1;\r
- if (i >= buf->size )\r
- i=0;\r
- }\r
- sem_up(semid);\r
-\r
-output_end:\r
- if (shmid != -1) \r
- shmdt(buf);\r
- \r
- return EXIT_SUCCESS; \r
-}\r
-\r
-static void interrupted(int sig){\r
- signal(SIGINT, SIG_IGN);\r
- longjmp(jmp_env, 1);\r
-}\r
-\r
-static void error_exit(const char *str){\r
- perror(str);\r
- //release all acquired resources\r
- if (shmid != -1) \r
- shmdt(buf);\r
-\r
- exit(1);\r
-}\r
-\r
+/* vi: set sw=4 ts=4: */
+/*
+ * circular buffer syslog implementation for busybox
+ *
+ * Copyright (C) 2000 by Gennady Feldman <gfeldman@gena01.com>
+ *
+ * Maintainer: Gennady Feldman <gfeldman@gena01.com> as of Mar 12, 2001
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#include "libbb.h"
+#include <sys/ipc.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+
+#define DEBUG 0
+
+enum { KEY_ID = 0x414e4547 }; /* "GENA" */
+
+struct shbuf_ds {
+ int32_t size; // size of data - 1
+ int32_t tail; // end of message list
+ char data[1]; // messages
+};
+
+static const struct sembuf init_sem[3] = {
+ {0, -1, IPC_NOWAIT | SEM_UNDO},
+ {1, 0}, {0, +1, SEM_UNDO}
+};
+
+struct globals {
+ struct sembuf SMrup[1]; // {0, -1, IPC_NOWAIT | SEM_UNDO},
+ struct sembuf SMrdn[2]; // {1, 0}, {0, +1, SEM_UNDO}
+ struct shbuf_ds *shbuf;
+};
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define SMrup (G.SMrup)
+#define SMrdn (G.SMrdn)
+#define shbuf (G.shbuf)
+#define INIT_G() \
+ do { \
+ memcpy(SMrup, init_sem, sizeof(init_sem)); \
+ } while (0)
+
+static void error_exit(const char *str) ATTRIBUTE_NORETURN;
+static void error_exit(const char *str)
+{
+ //release all acquired resources
+ shmdt(shbuf);
+ bb_perror_msg_and_die(str);
+}
+
+/*
+ * sem_up - up()'s a semaphore.
+ */
+static void sem_up(int semid)
+{
+ if (semop(semid, SMrup, 1) == -1)
+ error_exit("semop[SMrup]");
+}
+
+static void interrupted(int sig ATTRIBUTE_UNUSED)
+{
+ signal(SIGINT, SIG_IGN);
+ shmdt(shbuf);
+ exit(0);
+}
+
+int logread_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int logread_main(int argc, char **argv)
+{
+ int cur;
+ int log_semid; /* ipc semaphore id */
+ int log_shmid; /* ipc shared memory id */
+ smallint follow = getopt32(argv, "f");
+
+ INIT_G();
+
+ log_shmid = shmget(KEY_ID, 0, 0);
+ if (log_shmid == -1)
+ bb_perror_msg_and_die("can't find syslogd buffer");
+
+ /* Attach shared memory to our char* */
+ shbuf = shmat(log_shmid, NULL, SHM_RDONLY);
+ if (shbuf == NULL)
+ bb_perror_msg_and_die("can't access syslogd buffer");
+
+ log_semid = semget(KEY_ID, 0, 0);
+ if (log_semid == -1)
+ error_exit("can't get access to semaphores for syslogd buffer");
+
+ signal(SIGINT, interrupted);
+
+ /* Suppose atomic memory read */
+ /* Max possible value for tail is shbuf->size - 1 */
+ cur = shbuf->tail;
+
+ /* Loop for logread -f, one pass if there was no -f */
+ do {
+ unsigned shbuf_size;
+ unsigned shbuf_tail;
+ const char *shbuf_data;
+#if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING
+ int i;
+ int len_first_part;
+ int len_total = len_total; /* for gcc */
+ char *copy = copy; /* for gcc */
+#endif
+ if (semop(log_semid, SMrdn, 2) == -1)
+ error_exit("semop[SMrdn]");
+
+ /* Copy the info, helps gcc to realize that it doesn't change */
+ shbuf_size = shbuf->size;
+ shbuf_tail = shbuf->tail;
+ shbuf_data = shbuf->data; /* pointer! */
+
+ if (DEBUG)
+ printf("cur:%d tail:%i size:%i\n",
+ cur, shbuf_tail, shbuf_size);
+
+ if (!follow) {
+ /* advance to oldest complete message */
+ /* find NUL */
+ cur += strlen(shbuf_data + cur);
+ if (cur >= shbuf_size) { /* last byte in buffer? */
+ cur = strnlen(shbuf_data, shbuf_tail);
+ if (cur == shbuf_tail)
+ goto unlock; /* no complete messages */
+ }
+ /* advance to first byte of the message */
+ cur++;
+ if (cur >= shbuf_size) /* last byte in buffer? */
+ cur = 0;
+ } else { /* logread -f */
+ if (cur == shbuf_tail) {
+ sem_up(log_semid);
+ fflush(stdout);
+ sleep(1); /* TODO: replace me with a sleep_on */
+ continue;
+ }
+ }
+
+ /* Read from cur to tail */
+#if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING
+ len_first_part = len_total = shbuf_tail - cur;
+ if (len_total < 0) {
+ /* message wraps: */
+ /* [SECOND PART.........FIRST PART] */
+ /* ^data ^tail ^cur ^size */
+ len_total += shbuf_size;
+ }
+ copy = xmalloc(len_total + 1);
+ if (len_first_part < 0) {
+ /* message wraps (see above) */
+ len_first_part = shbuf_size - cur;
+ memcpy(copy + len_first_part, shbuf_data, shbuf_tail);
+ }
+ memcpy(copy, shbuf_data + cur, len_first_part);
+ copy[len_total] = '\0';
+ cur = shbuf_tail;
+#else
+ while (cur != shbuf_tail) {
+ fputs(shbuf_data + cur, stdout);
+ cur += strlen(shbuf_data + cur) + 1;
+ if (cur >= shbuf_size)
+ cur = 0;
+ }
+#endif
+ unlock:
+ /* release the lock on the log chain */
+ sem_up(log_semid);
+
+#if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING
+ for (i = 0; i < len_total; i += strlen(copy + i) + 1) {
+ fputs(copy + i, stdout);
+ }
+ free(copy);
+#endif
+ } while (follow);
+
+ shmdt(shbuf);
+
+ fflush_stdout_and_exit(EXIT_SUCCESS);
+}
projects / oweals / busybox.git / blobdiff