Small textdump enhancements.

Allow textdumps to be called explicitly from DDB.

If "dump" is called in DDB and textdumps are enabled then abort the
dump and tell the user to turn off textdumps.

Add options TEXTDUMP_PREFERRED to turn textdumps on by default.
Add options TEXTDUMP_VERBOSE to be a bit more verbose while textdumping.

Reviewed by: rwatson

MFC after:	2 weeks

4 files changed, 40 insertions, 6 deletions

diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 19fa20b..2fba664 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -389,6 +389,16 @@ options 	GDB
 options 	SYSCTL_DEBUG
 
 #
+# Enable textdump by default, this disables kernel core dumps.
+#
+options		TEXTDUMP_PREFERRED
+
+#
+# Enable extra debug messages while performing textdumps.
+#
+options		TEXTDUMP_VERBOSE
+
+#
 # NO_SYSCTL_DESCR omits the sysctl node descriptions to save space in the
 # resulting kernel.
 options		NO_SYSCTL_DESCR
diff --git a/sys/conf/options b/sys/conf/options
index 69a6efa..574d2e2 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -61,6 +61,8 @@ KDB_TRACE	opt_kdb.h
 KDB_UNATTENDED	opt_kdb.h
 KLD_DEBUG	opt_kld.h
 SYSCTL_DEBUG	opt_sysctl.h
+TEXTDUMP_PREFERRED	opt_ddb.h
+TEXTDUMP_VERBOSE	opt_ddb.h
 
 # Miscellaneous options.
 ADAPTIVE_LOCKMGRS
diff --git a/sys/ddb/db_command.c b/sys/ddb/db_command.c
index e0f14b9..cc4bde9 100644
--- a/sys/ddb/db_command.c
+++ b/sys/ddb/db_command.c
@@ -535,6 +535,11 @@ db_dump(db_expr_t dummy, boolean_t dummy2, db_expr_t dummy3, char *dummy4)
 {
 	int error;
 
+	if (textdump_pending) {
+		db_printf("textdump_pending set.\n"
+		    "run \"textdump unset\" first or \"textdump dump\" for a textdump.\n");
+		return;
+	}
 	error = doadump(FALSE);
 	if (error) {
 		db_printf("Cannot dump: ");
diff --git a/sys/ddb/db_textdump.c b/sys/ddb/db_textdump.c
index 8e78fbf..e664870 100644
--- a/sys/ddb/db_textdump.c
+++ b/sys/ddb/db_textdump.c
@@ -61,6 +61,8 @@ __FBSDID("$FreeBSD$");
 
 #include "opt_config.h"
 
+#include "opt_ddb.h"
+
 #include <sys/param.h>
 #include <sys/conf.h>
 #include <sys/kernel.h>
@@ -118,7 +120,11 @@ CTASSERT(sizeof(struct ustar_header) == TEXTDUMP_BLOCKSIZE);
  * Is a textdump scheduled?  If so, the shutdown code will invoke our dumpsys
  * routine instead of the machine-dependent kernel dump routine.
  */
-int	textdump_pending;
+#ifdef TEXTDUMP_PREFERRED
+int	textdump_pending = 1;
+#else
+int	textdump_pending = 0;
+#endif
 SYSCTL_INT(_debug_ddb_textdump, OID_AUTO, pending, CTLFLAG_RW,
     &textdump_pending, 0,
     "Perform textdump instead of regular kernel dump.");
@@ -201,6 +207,10 @@ textdump_mkustar(char *block_buffer, const char *filename, u_int size)
 {
 	struct ustar_header *uhp;
 
+#ifdef TEXTDUMP_VERBOSE
+	if (textdump_error == 0)
+		printf("textdump: creating '%s'.\n", filename);
+#endif
 	uhp = (struct ustar_header *)block_buffer;
 	bzero(uhp, sizeof(*uhp));
 	strlcpy(uhp->uh_filename, filename, sizeof(uhp->uh_filename));
@@ -237,6 +247,9 @@ textdump_writeblock(struct dumperinfo *di, off_t offset, char *buffer)
 		return (ENOSPC);
 	textdump_error = dump_write(di, buffer, 0, offset + di->mediaoffset,
 	    TEXTDUMP_BLOCKSIZE);
+	if (textdump_error)
+		printf("textdump_writeblock: offset %jd, error %d\n", (intmax_t)offset,
+		    textdump_error);
 	return (textdump_error);
 }
 
@@ -430,7 +443,7 @@ textdump_dumpsys(struct dumperinfo *di)
 	 * of data.
 	 */
 	if (di->mediasize < SIZEOF_METADATA + 2 * sizeof(kdh)) {
-		printf("Insufficient space on dump partition.\n");
+		printf("Insufficient space on dump partition for minimal textdump.\n");
 		return;
 	}
 	textdump_error = 0;
@@ -480,9 +493,9 @@ textdump_dumpsys(struct dumperinfo *di)
 	if (textdump_error == 0)
 		(void)dump_write(di, NULL, 0, 0, 0);
 	if (textdump_error == ENOSPC)
-		printf("Insufficient space on dump partition\n");
+		printf("Textdump: Insufficient space on dump partition\n");
 	else if (textdump_error != 0)
-		printf("Error %d writing dump\n", textdump_error);
+		printf("Textdump: Error %d writing dump\n", textdump_error);
 	else
 		printf("Textdump complete.\n");
 	textdump_pending = 0;
@@ -499,7 +512,7 @@ static void
 db_textdump_usage(void)
 {
 
-	db_printf("textdump [unset|set|status]\n");
+	db_printf("textdump [unset|set|status|dump]\n");
 }
 
 void
@@ -528,6 +541,10 @@ db_textdump_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 	} else if (strcmp(db_tok_string, "unset") == 0) {
 		textdump_pending = 0;
 		db_printf("textdump unset\n");
-	} else
+	} else if (strcmp(db_tok_string, "dump") == 0) {
+		textdump_pending = 1;
+		doadump(TRUE);
+	} else {
 		db_textdump_usage();
+	}
 }