diff options
| -rw-r--r-- | sysklogd/logread.c | 86 |
1 files changed, 68 insertions, 18 deletions
diff --git a/sysklogd/logread.c b/sysklogd/logread.c index 2692efbee..524178fe8 100644 --- a/sysklogd/logread.c +++ b/sysklogd/logread.c @@ -33,6 +33,7 @@ #include <sys/shm.h> #include <signal.h> #include <setjmp.h> +#include <unistd.h> #include "busybox.h" static const long KEY_ID = 0x414e4547; /*"GENA"*/ @@ -77,10 +78,15 @@ static inline void sem_down(int semid) extern int logread_main(int argc, char **argv) { int i; + int follow=0; - /* no options, no getopt */ - if (argc > 1) - bb_show_usage(); + if (argc == 2 && strcmp(argv[1],"-f")==0) { + follow = 1; + } else { + /* no options, no getopt */ + if (argc > 1) + bb_show_usage(); + } // handle intrrupt signal if (setjmp(jmp_env)) goto output_end; @@ -98,22 +104,66 @@ extern int logread_main(int argc, char **argv) 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"); - } + // Suppose atomic memory move + i = follow ? buf->tail : buf->head; + + do { +#undef RC_LOGREAD +#ifdef RC_LOGREAD + char *buf_data; + int log_len,j; +#endif + + sem_down(log_semid); + + //printf("head: %i tail: %i size: %i\n",buf->head,buf->tail,buf->size); + if (buf->head == buf->tail || i==buf->tail) { + if (follow) { + sem_up(log_semid); + sleep(1); /* TODO: replace me with a sleep_on */ + continue; + } else { + 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); + // Read Memory +#ifdef RC_LOGREAD + log_len = buf->tail - i; + if (log_len < 0) + log_len += buf->size; + buf_data = (char *)malloc(log_len); + if (!buf_data) + error_exit("malloc failed"); + + if (buf->tail < i) { + memcpy(buf_data, buf->data+i, buf->size-i); + memcpy(buf_data+buf->size-i, buf->data, buf->tail); + } else { + memcpy(buf_data, buf->data+i, buf->tail-i); + } + i = buf->tail; + +#else + while ( i != buf->tail) { + printf("%s", buf->data+i); + i+= strlen(buf->data+i) + 1; + if (i >= buf->size ) + i=0; + } +#endif + // release the lock on the log chain + sem_up(log_semid); + +#ifdef RC_LOGREAD + for (j=0; j < log_len; j+=strlen(buf_data+j)+1) { + printf("%s", buf_data+j); + if (follow) + fflush(stdout); + } + free(buf_data); +#endif + } while (follow); output_end: if (log_shmid != -1) |