Patch from Fillod Stephane

Add follow mode to logread, ala "tail -f /var/log/messages" Note: output to a slow serial terminal can have side effects on syslog because of the semaphore. In such case, define RC_LOGREAD.
author: Glenn L McGrath <bug1@ihug.co.nz> 2003-09-26 01:03:16 +0000
committer: Glenn L McGrath <bug1@ihug.co.nz> 2003-09-26 01:03:16 +0000
commit: f7dd10f67ce892530b2a2093b149722cf4903e76 (patch)
tree: c8376bd83d6a883e3a8d445087a358463a3f91a3 /sysklogd/logread.c
parent: a79220db6e71b7fa509ffa88a02ff1ea785bf811 (diff)
download: busybox-w32-f7dd10f67ce892530b2a2093b149722cf4903e76.tar.gz
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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 == 2 && strcmp(argv[1],"-f")==0) {
-        if (argc > 1)
+                follow = 1;
-                bb_show_usage();
+        } 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);    
+        // Suppose atomic memory move
-        // Read Memory 
+        i = follow ? buf->tail : buf->head;
-        i=buf->head;
+        do {
-        //printf("head: %i tail: %i size: %i\n",buf->head,buf->tail,buf->size);
+#undef RC_LOGREAD
-        if (buf->head == buf->tail) {
+#ifdef RC_LOGREAD
-                printf("<empty syslog>\n");
+                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) {
+                // Read Memory 
-                printf("%s", buf->data+i);
+#ifdef RC_LOGREAD
-                i+= strlen(buf->data+i) + 1;
+                log_len = buf->tail - i;
-                if (i >= buf->size )
+                if (log_len < 0)
-                        i=0;
+                        log_len += buf->size;
-        }
+                buf_data = (char *)malloc(log_len);
-        sem_up(log_semid);
+                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)
author	Glenn L McGrath <bug1@ihug.co.nz>	2003-09-26 01:03:16 +0000
committer	Glenn L McGrath <bug1@ihug.co.nz>	2003-09-26 01:03:16 +0000
commit	f7dd10f67ce892530b2a2093b149722cf4903e76 (patch)
tree	c8376bd83d6a883e3a8d445087a358463a3f91a3 /sysklogd/logread.c
parent	a79220db6e71b7fa509ffa88a02ff1ea785bf811 (diff)
download	busybox-w32-f7dd10f67ce892530b2a2093b149722cf4903e76.tar.gz busybox-w32-f7dd10f67ce892530b2a2093b149722cf4903e76.tar.bz2 busybox-w32-f7dd10f67ce892530b2a2093b149722cf4903e76.zip

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 @@
33	#include <sys/shm.h>	33	#include <sys/shm.h>
34	#include <signal.h>	34	#include <signal.h>
35	#include <setjmp.h>	35	#include <setjmp.h>
		36	#include <unistd.h>
36	#include "busybox.h"	37	#include "busybox.h"
37		38
38	static const long KEY_ID = 0x414e4547; /"GENA"/	39	static const long KEY_ID = 0x414e4547; /"GENA"/
@@ -77,10 +78,15 @@ static inline void sem_down(int semid)
77	extern int logread_main(int argc, char **argv)	78	extern int logread_main(int argc, char **argv)
78	{	79	{
79	int i;	80	int i;
		81	int follow=0;
80		82
81	/* no options, no getopt */	83	if (argc == 2 && strcmp(argv[1],"-f")==0) {
82	if (argc > 1)	84	follow = 1;
83	bb_show_usage();	85	} else {
		86	/* no options, no getopt */
		87	if (argc > 1)
		88	bb_show_usage();
		89	}
84		90
85	// handle intrrupt signal	91	// handle intrrupt signal
86	if (setjmp(jmp_env)) goto output_end;	92	if (setjmp(jmp_env)) goto output_end;
@@ -98,22 +104,66 @@ extern int logread_main(int argc, char **argv)
98	if ( (log_semid = semget(KEY_ID, 0, 0)) == -1)	104	if ( (log_semid = semget(KEY_ID, 0, 0)) == -1)
99	error_exit("Can't get access to semaphone(s) for circular buffer from syslogd");	105	error_exit("Can't get access to semaphone(s) for circular buffer from syslogd");
100		106
101	sem_down(log_semid);	107	// Suppose atomic memory move
102	// Read Memory	108	i = follow ? buf->tail : buf->head;
103	i=buf->head;	109
104		110	do {
105	//printf("head: %i tail: %i size: %i\n",buf->head,buf->tail,buf->size);	111	#undef RC_LOGREAD
106	if (buf->head == buf->tail) {	112	#ifdef RC_LOGREAD
107	printf("<empty syslog>\n");	113	char *buf_data;
108	}	114	int log_len,j;
		115	#endif
		116
		117	sem_down(log_semid);
		118
		119	//printf("head: %i tail: %i size: %i\n",buf->head,buf->tail,buf->size);
		120	if (buf->head == buf->tail \|\| i==buf->tail) {
		121	if (follow) {
		122	sem_up(log_semid);
		123	sleep(1); /* TODO: replace me with a sleep_on */
		124	continue;
		125	} else {
		126	printf("<empty syslog>\n");
		127	}
		128	}
109		129
110	while ( i != buf->tail) {	130	// Read Memory
111	printf("%s", buf->data+i);	131	#ifdef RC_LOGREAD
112	i+= strlen(buf->data+i) + 1;	132	log_len = buf->tail - i;
113	if (i >= buf->size )	133	if (log_len < 0)
114	i=0;	134	log_len += buf->size;
115	}	135	buf_data = (char *)malloc(log_len);
116	sem_up(log_semid);	136	if (!buf_data)
		137	error_exit("malloc failed");
		138
		139	if (buf->tail < i) {
		140	memcpy(buf_data, buf->data+i, buf->size-i);
		141	memcpy(buf_data+buf->size-i, buf->data, buf->tail);
		142	} else {
		143	memcpy(buf_data, buf->data+i, buf->tail-i);
		144	}
		145	i = buf->tail;
		146
		147	#else
		148	while ( i != buf->tail) {
		149	printf("%s", buf->data+i);
		150	i+= strlen(buf->data+i) + 1;
		151	if (i >= buf->size )
		152	i=0;
		153	}
		154	#endif
		155	// release the lock on the log chain
		156	sem_up(log_semid);
		157
		158	#ifdef RC_LOGREAD
		159	for (j=0; j < log_len; j+=strlen(buf_data+j)+1) {
		160	printf("%s", buf_data+j);
		161	if (follow)
		162	fflush(stdout);
		163	}
		164	free(buf_data);
		165	#endif
		166	} while (follow);
117		167
118	output_end:	168	output_end:
119	if (log_shmid != -1)	169	if (log_shmid != -1)