Re: directing xm dmesg to syslog

Re: directing xm dmesg to syslog

[MINAI Katsuhito]

[-- Attachment #1: Type: text/plain, Size: 1411 bytes --]

Hi all,

I made the logging daemon of the Xen message.
This daemon outputs the messege to syslog if messages were found
in the console ring by the polling every one second.

Following is the usage, but usually no option is necessary.
It will automatically be daemon.

usage: xenlogd [-h] [-k] [-r]
       -h: print help
       -k: kill alive logging daemon
       -r: restart logging daemon after kill alive one

Signed-off-by: Katsuhito Minai <minai@jp.fujitsu.com>

Best regards,
Katsuhito Minai



On Tue, 23 May 2006 16:31:44 +0100
Mark Williamson <mark.williamson@cl.cam.ac.uk> wrote:
> > short questin: I want to direct the oputput of xm dmesg in (near) realtime
> > to syslog.
> >
> > Is this possible?
> 
> dom0 Linux doesn't (currently) get any notifications that the xm dmesg output 
> has changed.
> 
> You could write a daemon to poll xm dmesg and send changes to syslog...  You 
> might like to consider having it clear the dmesg also, since it uses a 
> fixed-size buffer and won't work once that is full.
> 
> Cheers,
> Mark
> 
> -- 
> Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
> Mark: To answer a question with a question: What use is a skateboard?
> Dave: Skateboards have wheels.
> Mark: My wheel has a wheel!
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users


[-- Attachment #2: xenlogd.patch --]
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diff -r 4f1e39ec05d6 tools/xenlogd/Makefile
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/xenlogd/Makefile	Fri Jun 09 15:40:36 2006 +0900
@@ -0,0 +1,7 @@
+CC=gcc
+CFLAGS=-lxenctrl
+
+xenlogd:
+
+clean:
+	rm -f xenlogd
diff -r 4f1e39ec05d6 tools/xenlogd/TODO
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/xenlogd/TODO	Fri Jun 09 15:40:36 2006 +0900
@@ -0,0 +1,9 @@
+
+Following is the usage, but usually no option is necessary.
+It will automatically be daemon.
+
+usage: xenlogd [-h] [-n] [-k] [-r]
+       -h: print help
+       -n: no daemonize
+       -k: kill alive logging daemon
+       -r: restart logging daemon after kill alive one
diff -r 4f1e39ec05d6 tools/xenlogd/xenlogd.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/xenlogd/xenlogd.c	Fri Jun 09 15:40:36 2006 +0900
@@ -0,0 +1,283 @@
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <signal.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <fcntl.h>
+#include <string.h>
+
+
+#define XCDSIZE (4096)
+#define XENHEAD "(XEN) "
+#define PIDFILE "/var/run/xenlogd.pid"
+#define STARTMSG "logging has been started."
+
+static char *cmdname;
+
+quit(int xc, char *fmt, ...)
+{
+  va_list ap;
+  
+  va_start(ap, fmt);
+  vsyslog(LOG_KERN|LOG_ALERT, fmt, ap);
+  va_end(ap);
+  exit(xc);
+}
+
+putsyslog(char *bp, int size)
+{
+  static char *prsvp = NULL;
+  static int prsvc = 0;
+  char *endp;
+  int offset;
+
+  if ((prsvp == NULL) && ((prsvp = malloc(XCDSIZE)) == NULL)) {
+    quit(1, "allocate buffer failed");
+  }
+
+  bp[size] = '\0';
+
+  for (endp = bp + size; bp < endp; bp++) {
+    if (*bp == '\n') {
+      prsvp[prsvc]  = '\0';
+      if ((strncmp(prsvp, XENHEAD, strlen(XENHEAD)) == 0)) {
+	offset = strlen(XENHEAD);
+      } else {
+	offset = 0;
+      }
+      syslog(LOG_KERN|LOG_ALERT, "%s", prsvp + offset);
+      prsvc = 0;
+    } else {
+      prsvp[prsvc] = *bp;
+      prsvc++;
+    }
+  }
+}
+
+static void child_exit(int sig)
+{
+  while (waitpid(-1, NULL, WNOHANG) > 0);
+}
+
+static void term_daemon(int sig)
+{
+  unlink(PIDFILE);
+  quit(0, "logging ended normally.");
+}
+
+void daemonize()
+{
+  pid_t pid;
+  int fd;
+  int len;
+  int i;
+  int pfd[2];
+  char buf[1024];
+  
+  if (getppid() == 1) {
+    return;
+  }
+
+  signal(SIGPIPE, SIG_IGN);
+
+  if (pipe(pfd) < 0) {
+    quit(1, "open pipe failed");
+  }
+
+  if ((pid = fork()) > 0) {
+    exit(0);
+  } 
+  if (pid < 0) {
+    quit(1, "fork failed: errno = %d", errno);
+  }
+  
+  setsid();
+  
+  if ((pid = fork()) > 0) {
+    exit(0);
+  } 
+  if (pid < 0) {
+    quit(1, "fork failed: errno = %d", errno);
+  }
+  
+  if ((fd = open("/dev/null",O_RDWR)) == -1) {
+    quit(1, "open /dev/null failed: errno = %d", errno);
+  }
+  
+  for (i = 0; i <= 2; i++) {
+    close(i);
+    dup2(fd, i);
+  }
+  
+  close(fd);
+  umask(027);
+
+  if (chdir("/") < 0) {
+    quit(1, "change to root dir failed: errno = %d", errno);
+  }
+
+  pid = getpid();
+  snprintf(buf, sizeof(buf), "%s.%d", PIDFILE, pid);
+  
+  fd = open(buf, O_RDWR | O_CREAT | O_EXCL);
+  if (fd < 0) {
+    quit(1, "open %s failed: errno = %d", buf, errno);
+  }
+
+  if (link(buf, PIDFILE) < 0) {
+    unlink(buf);
+    quit(1, "other logging daemon may keep alive");
+  }
+  unlink(buf);
+  
+  len = sprintf(buf, "%d\n", pid);
+  if (write(fd, buf, len) < 0) {
+    quit(1, "write %s failed: errno = %d", PIDFILE, errno);
+  }
+
+  signal(SIGCHLD, child_exit);
+  signal(SIGTSTP, SIG_IGN);
+  signal(SIGTTOU, SIG_IGN);
+  signal(SIGTTIN, SIG_IGN);
+  sigset(SIGTERM, term_daemon);
+
+  close(pfd[1]);
+  read(pfd[0], buf, sizeof(buf));
+  close(pfd[0]);
+}
+
+int kill_daemon()
+{
+  int fd, pid, len;
+  char buf[1024];
+  char *comm;
+
+  fd = open(PIDFILE, O_RDWR);
+  if (fd < 0) {
+    if (errno == ENOENT) {
+      fprintf(stderr,"%s: no other daemon exist\n", cmdname);
+    } else {
+      perror("open error: ");
+    }
+    return(1);
+  }
+  len = read(fd, buf, sizeof(buf));
+  if (len < 0) {
+    perror("read error: ");
+    return(1);
+  }
+  close(fd);
+  buf[len] = '\0';
+  pid = atoi(buf);
+  
+  if (pid) {
+    snprintf(buf, sizeof(buf), "/proc/%d/stat", pid);
+    if ((fd = open(buf, O_RDONLY)) >= 0) {
+      len = read(fd, buf, sizeof(buf));
+      strtok(buf, " ");
+      if (((comm = strtok(NULL, " ")) != NULL) 
+	  && (strcmp(comm, "(xenlogd)") == 0)) {
+	if (kill(pid, SIGTERM) < 0) {
+	  perror("kill error: ");
+	  return(1);
+	}
+	while (kill(pid, SIGTERM) == 0);
+	if (errno != ESRCH) {
+	  perror("kill error: ");
+	}
+      }
+    }
+  }
+  if ((fd = open(PIDFILE, O_RDWR)) >= 0) {
+    close(fd);
+    unlink(PIDFILE);
+    fprintf(stderr, "%s: lockfile existed but no daemon alive. it was deleted.\n", cmdname);
+  }
+}
+
+void usage()
+{
+  fprintf(stderr, "usage: %s [-h] [-n] [-k] [-r]\n", cmdname);
+  fprintf(stderr, "       -h: print help\n");
+  fprintf(stderr, "       -n: no daemonize\n");
+  fprintf(stderr, "       -k: kill alive logging daemon\n");
+  fprintf(stderr, "       -r: restart logging daemon after kill alive one\n");
+  exit(0);
+}
+
+
+main(int argc, char *argv[])
+{
+  int fd;
+  int rc;
+  int bufsize;
+  int opt;
+  char *bufaddr;
+  char *tmpp;
+  int no_daemonize = 0;
+  int kill_d = 0;
+  int restart_d = 0;
+
+  cmdname = argv[0];
+
+  while ((opt = getopt(argc, argv, "hnkr")) != -1) {
+    switch (opt) {
+    case 'h':
+    case '?':
+    default:
+      usage();
+      break;
+    case 'n':
+      no_daemonize = 1;
+      break;
+    case 'r':
+      restart_d = 1;
+      /* fall through */
+    case 'k':
+      kill_d = 1;
+      break;
+    }
+  }
+
+  openlog(XENHEAD, LOG_NDELAY|LOG_CONS, LOG_KERN);
+
+  fd = xc_interface_open();
+  if (fd < 0) {
+    quit(1, "failed to open xen interface");
+  }
+
+  if ((bufaddr = malloc(XCDSIZE)) ==NULL) {
+    quit(1, "allocate buffer failed");
+  }
+
+  if (kill_d) {
+    kill_daemon();
+    if (!restart_d) {
+      exit(0);
+    }
+  }
+
+  if (!no_daemonize) {
+    daemonize();
+  }
+  
+  syslog(LOG_KERN|LOG_ALERT, "logging has been started.");
+
+  for (;;) {
+    bufsize = XCDSIZE;
+
+    rc = xc_readconsolering(fd, &bufaddr, &bufsize, 1);
+    if (rc < 0) {
+      quit(1, "error: read console ring: %d: errno %d", rc, errno);
+    }
+
+    if (bufsize) {
+      putsyslog(bufaddr, bufsize);
+    }
+    sleep(1);
+  }
+}

[-- Attachment #3: Type: text/plain, Size: 137 bytes --]

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Re: [Xen-devel] Re: directing xm dmesg to syslog

[Akio Takebe]

Hi, Minai

I think this is cool tool!
I want you to add xenlogd into /etc/init.d/xend.

And I have small comments.
See the below.

diff -r 4f1e39ec05d6 tools/xenlogd/Makefile
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/xenlogd/Makefile	Fri Jun 09 15:40:36 2006 +0900
@@ -0,0 +1,7 @@
+CC=gcc
+CFLAGS=-lxenctrl
+
+xenlogd:
+
+clean:
+	rm -f xenlogd
	You should add -Werror -g option into CFLAGS
	And you must add .PHONY, build, install section,
	because of "make tools" and "make install-tools"
	So you may add "SUBDIRS-y += xenlogd" into tools/Makefile 


diff -r 4f1e39ec05d6 tools/xenlogd/xenlogd.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/xenlogd/xenlogd.c	Fri Jun 09 15:40:36 2006 +0900
@@ -0,0 +1,283 @@
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <signal.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <fcntl.h>
+#include <string.h>
+
+
+#define XCDSIZE (4096)
+#define XENHEAD "(XEN) "
+#define PIDFILE "/var/run/xenlogd.pid"
+#define STARTMSG "logging has been started."
+
	And STARTMSG isn't used. :-)

This xenlog tools clear a reading part of console buffer.
I think xenlogd which don't clear the buffer is more cool.
But this fix might modify xen's code.
So this fix is trade off.
Hmm.... 
I hope other comments from community. :-)

Best Regards,

Akio Takebe

>Hi all,
>
>I made the logging daemon of the Xen message.
>This daemon outputs the messege to syslog if messages were found
>in the console ring by the polling every one second.
>
>Following is the usage, but usually no option is necessary.
>It will automatically be daemon.
>
>usage: xenlogd [-h] [-k] [-r]
>       -h: print help
>       -k: kill alive logging daemon
>       -r: restart logging daemon after kill alive one
>
>Signed-off-by: Katsuhito Minai <minai@jp.fujitsu.com>
>
>Best regards,
>Katsuhito Minai
>
>
>
>On Tue, 23 May 2006 16:31:44 +0100
>Mark Williamson <mark.williamson@cl.cam.ac.uk> wrote:
>> > short questin: I want to direct the oputput of xm dmesg in (near) 
>> > realtime
>> > to syslog.
>> >
>> > Is this possible?
>> 
>> dom0 Linux doesn't (currently) get any notifications that the xm dmesg 
>> output 
>> has changed.
>> 
>> You could write a daemon to poll xm dmesg and send changes to syslog...  
>> You 
>> might like to consider having it clear the dmesg also, since it uses a 
>> fixed-size buffer and won't work once that is full.
>> 
>> Cheers,
>> Mark
>> 
>> -- 
>> Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
>> Mark: To answer a question with a question: What use is a skateboard?
>> Dave: Skateboards have wheels.
>> Mark: My wheel has a wheel!
>> 
>> _______________________________________________
>> Xen-users mailing list
>> Xen-users@lists.xensource.com
>> http://lists.xensource.com/xen-users
>
>
>-------------------------------text/plain-------------------------------
>_______________________________________________
>Xen-devel mailing list
>Xen-devel@lists.xensource.com
>http://lists.xensource.com/xen-devel

[PATCH] [0/4] put xen console message into syslog but xm dmesg is not affected

[MINAI Katsuhito]

Hi Akio and all

Thank you for your comments. I'm sorry that the answer is late.
I will send the following 4 patches following this mail.

[1/4] add read pointer to the xen console ring
[2/4] add xenlogd daemon for xen console logging
[3/4] modify xend for automatically starting xenlogd
[4/4] README of xenlogd


> This xenlog tools clear a reading part of console buffer.
> I think xenlogd which don't clear the buffer is more cool.
> But this fix might modify xen's code.
> So this fix is trade off.

I solved this problem by adding another read pointer of the console 
buffer of Xen for xenlogd daemon.
The pointer is used when a negative value is specified 
for the fourth argument(named "clear") of the xc_readconsolering() function. 

The console can be logged independently by this correction 
with the operation of the xm dmesg command. 



> 	You should add -Werror -g option into CFLAGS
> 	And you must add .PHONY, build, install section,
> 	because of "make tools" and "make install-tools"
> 	So you may add "SUBDIRS-y += xenlogd" into tools/Makefile 

I decided to put xenlogd on tools/misc in this patch though I made a 
new directory in the last patch for xenlogd. 

And, xenlogd was automatically started from xend python script.
So you have nothing to do except applying the patch.


Best regards,
Katsuhito Minai


On Thu, 15 Jun 2006 22:32:53 +0900
Akio Takebe <takebe_akio@jp.fujitsu.com> wrote:
> Hi, Minai
> 
> I think this is cool tool!
> I want you to add xenlogd into /etc/init.d/xend.
> 
> And I have small comments.
> See the below.
> 
> diff -r 4f1e39ec05d6 tools/xenlogd/Makefile
> --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
> +++ b/tools/xenlogd/Makefile	Fri Jun 09 15:40:36 2006 +0900
> @@ -0,0 +1,7 @@
> +CC=gcc
> +CFLAGS=-lxenctrl
> +
> +xenlogd:
> +
> +clean:
> +	rm -f xenlogd
> 	You should add -Werror -g option into CFLAGS
> 	And you must add .PHONY, build, install section,
> 	because of "make tools" and "make install-tools"
> 	So you may add "SUBDIRS-y += xenlogd" into tools/Makefile 
> 
> 
> diff -r 4f1e39ec05d6 tools/xenlogd/xenlogd.c
> --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
> +++ b/tools/xenlogd/xenlogd.c	Fri Jun 09 15:40:36 2006 +0900
> @@ -0,0 +1,283 @@
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <sys/wait.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <syslog.h>
> +#include <signal.h>
> +#include <errno.h>
> +#include <stdarg.h>
> +#include <fcntl.h>
> +#include <string.h>
> +
> +
> +#define XCDSIZE (4096)
> +#define XENHEAD "(XEN) "
> +#define PIDFILE "/var/run/xenlogd.pid"
> +#define STARTMSG "logging has been started."
> +
> 	And STARTMSG isn't used. :-)
> 
> This xenlog tools clear a reading part of console buffer.
> I think xenlogd which don't clear the buffer is more cool.
> But this fix might modify xen's code.
> So this fix is trade off.
> Hmm.... 
> I hope other comments from community. :-)
> 
> Best Regards,
> 
> Akio Takebe
> 
> >Hi all,
> >
> >I made the logging daemon of the Xen message.
> >This daemon outputs the messege to syslog if messages were found
> >in the console ring by the polling every one second.
> >
> >Following is the usage, but usually no option is necessary.
> >It will automatically be daemon.
> >
> >usage: xenlogd [-h] [-k] [-r]
> >       -h: print help
> >       -k: kill alive logging daemon
> >       -r: restart logging daemon after kill alive one
> >
> >Signed-off-by: Katsuhito Minai <minai@jp.fujitsu.com>
> >
> >Best regards,
> >Katsuhito Minai
> >
> >
> >
> >On Tue, 23 May 2006 16:31:44 +0100
> >Mark Williamson <mark.williamson@cl.cam.ac.uk> wrote:
> >> > short questin: I want to direct the oputput of xm dmesg in (near) 
> >> > realtime
> >> > to syslog.
> >> >
> >> > Is this possible?
> >> 
> >> dom0 Linux doesn't (currently) get any notifications that the xm dmesg 
> >> output 
> >> has changed.
> >> 
> >> You could write a daemon to poll xm dmesg and send changes to syslog...  
> >> You 
> >> might like to consider having it clear the dmesg also, since it uses a 
> >> fixed-size buffer and won't work once that is full.
> >> 
> >> Cheers,
> >> Mark
> >> 
> >> -- 
> >> Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
> >> Mark: To answer a question with a question: What use is a skateboard?
> >> Dave: Skateboards have wheels.
> >> Mark: My wheel has a wheel!
> >> 
> >> _______________________________________________
> >> Xen-users mailing list
> >> Xen-users@lists.xensource.com
> >> http://lists.xensource.com/xen-users
> >
> >
> >-------------------------------text/plain-------------------------------
> >_______________________________________________
> >Xen-devel mailing list
> >Xen-devel@lists.xensource.com
> >http://lists.xensource.com/xen-devel
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel