diff options
Diffstat (limited to 'sysklogd')
| -rw-r--r-- | sysklogd/logread.c | 80 |
1 files changed, 31 insertions, 49 deletions
diff --git a/sysklogd/logread.c b/sysklogd/logread.c index 4427cf3..d092056 100644 --- a/sysklogd/logread.c +++ b/sysklogd/logread.c @@ -11,37 +11,30 @@ #include "busybox.h" #include <sys/ipc.h> -//#include <sys/types.h> #include <sys/sem.h> #include <sys/shm.h> -//#include <signal.h> -//#include <setjmp.h> #define DEBUG 0 -static const long KEY_ID = 0x414e4547; /* "GENA" */ +enum { KEY_ID = 0x414e4547 }; /* "GENA" */ static struct shbuf_ds { - int32_t size; // size of data written - int32_t head; // start of message list - int32_t tail; // end of message list - char data[1]; // data/messages -} *buf; // shared memory pointer - + int32_t size; // size of data written + int32_t head; // start of message list + int32_t tail; // end of message list + char data[1]; // data/messages +} *buf; // 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 void error_exit(const char *str) ATTRIBUTE_NORETURN; static void error_exit(const char *str) { //release all acquired resources - if (log_shmid != -1) - shmdt(buf); + shmdt(buf); bb_perror_msg_and_die(str); } @@ -54,16 +47,7 @@ static void sem_up(int semid) error_exit("semop[SMrup]"); } -/* - * sem_down - down()'s a semaphore - */ -static void sem_down(int semid) -{ - if (semop(semid, SMrdn, 2) == -1) - error_exit("semop[SMrdn]"); -} - -static void interrupted(int sig) +static void interrupted(int sig ATTRIBUTE_UNUSED) { signal(SIGINT, SIG_IGN); shmdt(buf); @@ -73,23 +57,18 @@ static void interrupted(int sig) int logread_main(int argc, char **argv) { int cur; - int follow = 1; - - if (argc != 2 || argv[1][0]!='-' || argv[1][1]!='f' ) { - follow = 0; - /* no options, no getopt */ - if (argc > 1) - bb_show_usage(); - } + int log_semid; /* ipc semaphore id */ + int log_shmid; /* ipc shared memory id */ + smallint follow = getopt32(argc, argv, "f"); log_shmid = shmget(KEY_ID, 0, 0); if (log_shmid == -1) - error_exit("can't find circular buffer"); + bb_perror_msg_and_die("can't find syslogd buffer"); // Attach shared memory to our char* buf = shmat(log_shmid, NULL, SHM_RDONLY); if (buf == NULL) - error_exit("can't get access to syslogd buffer"); + bb_perror_msg_and_die("can't access syslogd buffer"); log_semid = semget(KEY_ID, 0, 0); if (log_semid == -1) @@ -102,38 +81,42 @@ int logread_main(int argc, char **argv) cur = follow ? buf->tail : buf->head; do { -#ifdef CONFIG_FEATURE_LOGREAD_REDUCED_LOCKING +#if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING char *buf_data; int log_len, j; #endif - sem_down(log_semid); + if (semop(log_semid, SMrdn, 2) == -1) + error_exit("semop[SMrdn]"); if (DEBUG) - printf("head:%i cur:%d tail:%i size:%i\n", buf->head, cur, buf->tail, buf->size); + printf("head:%i cur:%d tail:%i size:%i\n", + buf->head, cur, buf->tail, buf->size); if (buf->head == buf->tail || cur == buf->tail) { if (follow) { sem_up(log_semid); - sleep(1); /* TODO: replace me with a sleep_on */ + fflush(stdout); + sleep(1); /* TODO: replace me with a sleep_on */ continue; - } else { - printf("<empty syslog>\n"); } + puts("<empty syslog>"); } // Read Memory -#ifdef CONFIG_FEATURE_LOGREAD_REDUCED_LOCKING +#if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING log_len = buf->tail - cur; if (log_len < 0) log_len += buf->size; buf_data = xmalloc(log_len); - if (buf->tail >= cur) { - memcpy(buf_data, buf->data + cur, log_len); - } else { - memcpy(buf_data, buf->data + cur, buf->size - cur); + if (buf->tail >= cur) + j = log_len; + else + j = buf->size - cur; + memcpy(buf_data, buf->data + cur, j); + + if (buf->tail < cur) memcpy(buf_data + buf->size - cur, buf->data, buf->tail); - } cur = buf->tail; #else while (cur != buf->tail) { @@ -146,16 +129,15 @@ int logread_main(int argc, char **argv) // release the lock on the log chain sem_up(log_semid); -#ifdef CONFIG_FEATURE_LOGREAD_REDUCED_LOCKING +#if ENABLE_FEATURE_LOGREAD_REDUCED_LOCKING for (j = 0; j < log_len; j += strlen(buf_data+j) + 1) { fputs(buf_data + j, stdout); } free(buf_data); #endif - fflush(stdout); } while (follow); shmdt(buf); - return EXIT_SUCCESS; + fflush_stdout_and_exit(EXIT_SUCCESS); } |