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authorGravatar Phil Sutter <phil.sutter@viprinet.com>2015-03-22 17:36:20 +0100
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2015-03-22 17:37:20 +0100
commit92edab1aa6eae45ac8fa0cec8c8df9a47f547300 (patch)
tree738a5d864011189939847bceb8620af6371d4e62 /sysklogd
parent6d8ea1d50ec6088c51a61ab3e9f849b7845dce6b (diff)
downloadbusybox-92edab1aa6eae45ac8fa0cec8c8df9a47f547300.tar.gz
busybox-92edab1aa6eae45ac8fa0cec8c8df9a47f547300.tar.bz2
logread: implement dumpfollow mode of operation
This is basically a combination of the default (dump mode) and -f (follow mode). Specifying -F makes logread first dump the log buffer and then immediately start following it. function old new delta packed_usage 30412 30443 +31 logread_main 491 497 +6 Signed-off-by: Phil Sutter <phil.sutter@viprinet.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'sysklogd')
-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();