git: bbf95a9b8481 - main - exterror(9): split category into multiple sources

The branch main has been updated by brooks:

URL: https://cgit.FreeBSD.org/src/commit/?id=bbf95a9b8481e41a99b301e12338e1cda6915a01

commit bbf95a9b8481e41a99b301e12338e1cda6915a01
Author:     Brooks Davis <[email protected]>
AuthorDate: 2026-08-03 16:48:27 +0000
Commit:     Brooks Davis <[email protected]>
CommitDate: 2026-08-03 21:43:22 +0000

    exterror(9): split category into multiple sources
    
    The static, global index into an array of strings is simple, cheap,
    and works for the base kernel, but is unworkable for (potentially
    third-party) kernel modules or for arbitrary userspace code.  Swipe a
    few of the top bits of category to indicate a source with all-zeros
    being the current model (EXTERR_CAT_SRC_KERN_STATIC).  Add two
    additional sources EXTERR_CAT_SRC_KERN_DYNAMIC and EXTERR_CAT_SRC_USER
    with stub implementations.
    
    Reviewed by:    kib
    Sponsored by:   Innovate UK
    Differential Revision:  https://reviews.freebsd.org/D58236
---
 lib/libc/gen/uexterr_format.c | 18 +++++++++++++++---
 sys/sys/exterr_cat.h          | 12 ++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/lib/libc/gen/uexterr_format.c b/lib/libc/gen/uexterr_format.c
index 308220adea1f..df93ae1447cd 100644
--- a/lib/libc/gen/uexterr_format.c
+++ b/lib/libc/gen/uexterr_format.c
@@ -25,10 +25,22 @@ static const char * const cat_to_filenames[] = {
 static const char *
 cat_to_filename(int category)
 {
-	if (category < 0 || category >= nitems(cat_to_filenames) ||
-	    cat_to_filenames[category] == NULL)
+	switch (EXTERR_CAT_SRC(category)) {
+	case EXTERR_CAT_SRC_KERN_STATIC:
+		if (category < 0 || category >= nitems(cat_to_filenames) ||
+		    cat_to_filenames[category] == NULL)
+			return ("unknown:kern");
+		return (cat_to_filenames[category]);
+
+	case EXTERR_CAT_SRC_KERN_DYNAMIC:
+		return ("unknown:kern");
+
+	case EXTERR_CAT_SRC_USER:
+		return ("unknown:user");
+
+	default:
 		return ("unknown");
-	return (cat_to_filenames[category]);
+	}
 }
 
 static const char exterror_verbose_name[] = "EXTERROR_VERBOSE";
diff --git a/sys/sys/exterr_cat.h b/sys/sys/exterr_cat.h
index 637cecdcbcd0..1b56e241023b 100644
--- a/sys/sys/exterr_cat.h
+++ b/sys/sys/exterr_cat.h
@@ -22,6 +22,18 @@
 #ifndef _SYS_EXTERR_CAT_H_
 #define	_SYS_EXTERR_CAT_H_
 
+#define	_EXTERR_CAT_SRC_SHIFT		28
+#define	EXTERR_CAT_SRC_MASK		(0xf << _EXTERR_CAT_SRC_SHIFT)
+
+#define	EXTERR_CAT_SRC_KERN_STATIC	(0 << _EXTERR_CAT_SRC_SHIFT)
+#define	EXTERR_CAT_SRC_KERN_DYNAMIC	(1 << _EXTERR_CAT_SRC_SHIFT)
+#define	EXTERR_CAT_SRC_USER		(2 << _EXTERR_CAT_SRC_SHIFT)
+
+#define	EXTERR_CAT_SRC(c)	((c) & EXTERR_CAT_SRC_MASK)
+#define	EXTERR_CAT(c)		((c) & ~EXTERR_CAT_SRC_MASK)
+
+#define	EXTERR_CAT_NONE		0
+
 #define	EXTERR_CAT_MMAP		1
 #define	EXTERR_CAT_FILEDESC	2
 #define	EXTERR_KTRACE		3	/* To allow inclusion of this