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-rw-r--r--sysklogd/logread.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/sysklogd/logread.c b/sysklogd/logread.c
index bea73d932..da4a4d4df 100644
--- a/sysklogd/logread.c
+++ b/sysklogd/logread.c
@@ -10,10 +10,11 @@
*/
//usage:#define logread_trivial_usage
-//usage: "[-f]"
+//usage: "[-fF]"
//usage:#define logread_full_usage "\n\n"
//usage: "Show messages in syslogd's circular buffer\n"
//usage: "\n -f Output data as log grows"
+//usage: "\n -F Same as -f, but dump buffer first"
#include "libbb.h"
#include <sys/ipc.h>
@@ -83,7 +84,7 @@ int logread_main(int argc UNUSED_PARAM, char **argv)
unsigned cur;
int log_semid; /* ipc semaphore id */
int log_shmid; /* ipc shared memory id */
- smallint follow = getopt32(argv, "f");
+ int follow = getopt32(argv, "fF");
INIT_G();
@@ -106,7 +107,7 @@ int logread_main(int argc UNUSED_PARAM, char **argv)
/* Max possible value for tail is shbuf->size - 1 */
cur = shbuf->tail;
- /* Loop for logread -f, one pass if there was no -f */
+ /* Loop for -f or -F, one pass otherwise */
do {
unsigned shbuf_size;
unsigned shbuf_tail;
@@ -129,7 +130,12 @@ int logread_main(int argc UNUSED_PARAM, char **argv)
printf("cur:%u tail:%u size:%u\n",
cur, shbuf_tail, shbuf_size);
- if (!follow) {
+ if (!(follow & 1)) { /* not -f */
+ /* if -F, "convert" it to -f, so that we dont
+ * dump the entire buffer on each iteration
+ */
+ follow >>= 1;
+
/* advance to oldest complete message */
/* find NUL */
cur += strlen(shbuf_data + cur);
@@ -142,7 +148,7 @@ int logread_main(int argc UNUSED_PARAM, char **argv)
cur++;
if (cur >= shbuf_size) /* last byte in buffer? */
cur = 0;
- } else { /* logread -f */
+ } else { /* -f */
if (cur == shbuf_tail) {
sem_up(log_semid);
fflush_all();