[Sheepdog] [PATCH] Enable sheepdog generate core dump file

[huxinwei]

> -----Original Message-----
> From: sheepdog-bounces at lists.wpkg.org
> [mailto:sheepdog-bounces at lists.wpkg.org] On Behalf Of Yunkai Zhang
> Sent: Friday, March 02, 2012 11:42 PM
> To: morita.kazutaka at lab.ntt.co.jp
> Cc: Yunkai Zhang; sheepdog at lists.wpkg.org
> Subject: [Sheepdog] [PATCH] Enable sheepdog generate core dump file
> 
> If sheepdog received SIGSEGV signal and we have enabled
> OS to generate it, core dump file would be created in
> LOCALSTATEDIR/lib/sheepdog directory.
> 
> We can find the vaule of LOCALSTATEDIR in include/config.h.
> 
> Signed-off-by: Yunkai Zhang <qiushu.zyk at taobao.com>
> ---
>  lib/logger.c |   20 +++++++++++++++-----
>  1 files changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/logger.c b/lib/logger.c
> index 5be035a..c78329e 100644
> --- a/lib/logger.c
> +++ b/lib/logger.c
> @@ -29,6 +29,7 @@
>  #include <sys/wait.h>
>  #include <sys/prctl.h>
> 
> +#include "../include/config.h"
>  #include "logger.h"
>  #include "util.h"
> 
> @@ -355,11 +356,12 @@ static void log_flush(void)
> 
>  static void log_sigsegv(void)
>  {
> +	(void)signal(SIGSEGV, SIG_DFL);
>  	vprintf(SDOG_ERR, "logger pid %d exiting abnormally\n", getpid());
>  	log_flush();
>  	closelog();
>  	free_logarea();
> -	exit(1);
> +	raise(SIGSEGV);

Er, I'm not sure if this makes sense here to raise the signal again.

Here in logger, SIGSEGV usually generated by the exiting of parent process (caused by prctl).
So it has nothing to do with the core dump of sheep itself.

Actually, I'd like to propose a patch to rename log_sigsegv to log_sigparentexit ;)
Will send out a patch about logger soon.

>  }
> 
>  int log_init(char *program_name, int size, int is_daemon, int level, char
> *outfile)
> @@ -372,6 +374,7 @@ int log_init(char *program_name, int size, int
> is_daemon, int level, char *outfi
>  	semkey = random();
> 
>  	if (is_daemon) {
> +		const char *run_dir;
>  		struct sigaction sa_old;
>  		struct sigaction sa_new;
>  		int fd;
> @@ -395,6 +398,17 @@ int log_init(char *program_name, int size, int
> is_daemon, int level, char *outfi
> 
>  		la->active = 1;
>  		la->fd = fd;
> +
> +		run_dir = LOCALSTATEDIR "/lib/sheepdog";
> +	        if ((mkdir(run_dir, 0700)) == -1 && errno != EEXIST) {
> +			syslog(LOG_ERR, "failed to mkdir -p to %s: %m\n", run_dir);
> +		}
> +
> +		if (chdir(run_dir) < 0) {
> +			syslog(LOG_ERR, "failed to chdir to %s: %m\n", run_dir);
> +			exit(1);
> +		}
> +
>  		pid = fork();
>  		if (pid < 0) {
>  			syslog(LOG_ERR, "failed to fork the logger process: %m\n");
> @@ -414,10 +428,6 @@ int log_init(char *program_name, int size, int
> is_daemon, int level, char *outfi
>  		dup2(fd, 1);
>  		dup2(fd, 2);
>  		setsid();
> -		if (chdir("/") < 0) {
> -			syslog(LOG_ERR, "failed to chdir to /: %m\n");
> -			exit(1);
> -		}
> 
>  		/* flush on daemon's crash */
>  		sa_new.sa_handler = (void*)log_sigsegv;
> --
> 1.7.7.6
> 
> --
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