Re: [PATCH 1/7] xfs_scrub: log operational messages when interactive

On Mon, Feb 12, 2018 at 02:47:14PM -0600, Eric Sandeen wrote:

On 2/5/18 5:22 PM, Darrick J. Wong wrote:

quoted

From: Darrick J. Wong <redacted>

Record the output of an interactive session in the system log so that
future support requests can get a better picture of what happened.

Signed-off-by: Darrick J. Wong <redacted>

I really want to log things, but I'm conflicted about spamming syslog.
I'm wondering if a generic /var/log/xfs.log would be good, and it could
eventually log all xfs-related administrative actions and outcomes with
a libfrog library helper... I don't know how non-syslog log files are
handled in general, does everybody just roll their own?

Evidently rsyslog actually can filter things out to a separate file.
For example, /etc/rsyslog.d/20-ufw.conf:

# Log kernel generated UFW log messages to file
:msg,contains,"[UFW " /var/log/ufw.log

# Uncomment the following to stop logging anything that matches the last
# rule.  Doing this will stop logging kernel generated UFW log messages
# to the file normally containing kern.* messages (eg,
# /var/log/kern.log)
#& stop

Therefore, it looks as though we actually /can/ use the regular syslog
calls from various xfs utilities and (if rsyslog is up) forward the
output to a place where support can capture it later.

--D

I'm inclined to leave this one out of 4.15 for now while I/we think
about the big picture here.

-Eric

quoted

---
 scrub/common.c |   37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/scrub/common.c b/scrub/common.c
index 17c3699..672f286 100644
--- a/scrub/common.c
+++ b/scrub/common.c

@@ -21,6 +21,7 @@
 #include <pthread.h>
 #include <stdbool.h>
 #include <sys/statvfs.h>
+#include <syslog.h>
 #include "platform_defs.h"
 #include "xfs.h"
 #include "xfs_fs.h"

@@ -29,6 +30,8 @@
 #include "common.h"
 #include "progress.h"
 
+extern char		*progname;
+
 /*
  * Reporting Status to the Console
  *

@@ -64,6 +67,12 @@ static const char *err_str[] = {
 	[S_PREEN]	= "Optimized",
 };
 
+static int log_level[] = {
+	[S_ERROR]	= LOG_ERR,
+	[S_WARN]	= LOG_WARNING,
+	[S_INFO]	= LOG_INFO,
+};
+
 /* If stream is a tty, clear to end of line to clean up progress bar. */
 static inline const char *stream_start(FILE *stream)
 {

@@ -73,6 +82,8 @@ static inline const char *stream_start(FILE *stream)
 }
 
 /* Print a warning string and some warning text. */
+#define LOG_BUFSZ	4096
+#define LOGNAME_BUFSZ	256
 void
 __str_out(
 	struct scrub_ctx	*ctx,

@@ -110,6 +121,32 @@ __str_out(
 		va_end(args);
 	}
 
+	/* If we're running interactively, log the message to syslog too. */
+	if (isatty(fileno(stdin)) && !debug) {
+		char	logname[LOGNAME_BUFSZ];
+
+		snprintf(logname, LOGNAME_BUFSZ, "%s@%s", progname,
+				ctx->mntpoint);
+		openlog(logname, LOG_PID, LOG_DAEMON);
+
+		if (error) {
+			syslog(LOG_ERR, "%s: %s: %s.",
+					_(err_str[level]), descr,
+					strerror_r(error, buf, DESCR_BUFSZ));
+		} else {
+			char	buf[LOG_BUFSZ];
+			int	sz;
+
+			sz = snprintf(buf, LOG_BUFSZ, "%s: %s: ",
+					_(err_str[level]), descr);
+			va_start(args, format);
+			vsnprintf(buf + sz, LOG_BUFSZ - sz, format, args);
+			va_end(args);
+			syslog(log_level[level], "%s", buf);
+		}
+		closelog();
+	}
+
 	if (debug)
 		fprintf(stream, _(" (%s line %d)"), file, line);
 	fprintf(stream, "\n");

--

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