From efbbbf570d70bf488555019bfe0db2207aa12c44 Mon Sep 17 00:00:00 2001
From: rwatson <rwatson@FreeBSD.org>
Date: Tue, 1 Nov 2005 12:36:19 +0000
Subject: [PATCH] Replace ktr_buffer pointer in struct ktr_header with a
 ktr_unused intptr_t.  The buffer length needs to be written to disk as part
 of the trace log, but the kernel pointer for the buffer does not. Add a new
 ktr_buffer pointer to the kernel-only ktrace request structure to hold that
 pointer.  This frees up an integer in the ktrace record format that can be
 used to hold the threadid, although older ktrace files will have a garbage
 ktr_buffer field (or more accurately, a kernel pointer value).

MFC after:		2 weeks
Space requested by:	davidxu
---
 sys/kern/kern_ktrace.c | 20 +++++++++++---------
 sys/sys/ktrace.h       |  2 +-
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/sys/kern/kern_ktrace.c b/sys/kern/kern_ktrace.c
index 850e9b02bfe6..e4b4b5c76c94 100644
--- a/sys/kern/kern_ktrace.c
+++ b/sys/kern/kern_ktrace.c
@@ -64,6 +64,7 @@ static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
 
 struct ktr_request {
 	struct	ktr_header ktr_header;
+	void	*ktr_buffer;
 	struct	ucred *ktr_cred;
 	struct	vnode *ktr_vp;
 	union {
@@ -237,7 +238,8 @@ ktr_getrequest(int type)
 		microtime(&req->ktr_header.ktr_time);
 		req->ktr_header.ktr_pid = p->p_pid;
 		bcopy(p->p_comm, req->ktr_header.ktr_comm, MAXCOMLEN + 1);
-		req->ktr_header.ktr_buffer = NULL;
+		req->ktr_header.ktr_unused = 0;
+		req->ktr_buffer = NULL;
 		req->ktr_header.ktr_len = 0;
 	} else {
 		p->p_traceflag |= KTRFAC_DROP;
@@ -272,8 +274,8 @@ ktr_freerequest(struct ktr_request *req)
 		vrele(req->ktr_vp);
 		mtx_unlock(&Giant);
 	}
-	if (req->ktr_header.ktr_buffer != NULL)
-		free(req->ktr_header.ktr_buffer, M_KTRACE);
+	if (req->ktr_buffer != NULL)
+		free(req->ktr_buffer, M_KTRACE);
 	mtx_lock(&ktrace_mtx);
 	STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list);
 	mtx_unlock(&ktrace_mtx);
@@ -340,7 +342,7 @@ ktrsyscall(code, narg, args)
 	ktp->ktr_narg = narg;
 	if (buflen > 0) {
 		req->ktr_header.ktr_len = buflen;
-		req->ktr_header.ktr_buffer = buf;
+		req->ktr_buffer = buf;
 	}
 	ktr_submitrequest(req);
 }
@@ -387,7 +389,7 @@ ktrnamei(path)
 	}
 	if (namelen > 0) {
 		req->ktr_header.ktr_len = namelen;
-		req->ktr_header.ktr_buffer = buf;
+		req->ktr_buffer = buf;
 	}
 	ktr_submitrequest(req);
 }
@@ -436,7 +438,7 @@ ktrgenio(fd, rw, uio, error)
 	ktg->ktr_fd = fd;
 	ktg->ktr_rw = rw;
 	req->ktr_header.ktr_len = datalen;
-	req->ktr_header.ktr_buffer = buf;
+	req->ktr_buffer = buf;
 	ktr_submitrequest(req);
 }
 
@@ -684,7 +686,7 @@ utrace(td, uap)
 		free(cp, M_KTRACE);
 		return (ENOMEM);
 	}
-	req->ktr_header.ktr_buffer = cp;
+	req->ktr_buffer = cp;
 	req->ktr_header.ktr_len = uap->len;
 	ktr_submitrequest(req);
 	return (0);
@@ -827,8 +829,8 @@ ktr_writerequest(struct ktr_request *req)
 		kth->ktr_len += datalen;
 	}
 	if (buflen != 0) {
-		KASSERT(kth->ktr_buffer != NULL, ("ktrace: nothing to write"));
-		aiov[auio.uio_iovcnt].iov_base = kth->ktr_buffer;
+		KASSERT(req->ktr_buffer != NULL, ("ktrace: nothing to write"));
+		aiov[auio.uio_iovcnt].iov_base = req->ktr_buffer;
 		aiov[auio.uio_iovcnt].iov_len = buflen;
 		auio.uio_resid += buflen;
 		auio.uio_iovcnt++;
diff --git a/sys/sys/ktrace.h b/sys/sys/ktrace.h
index e2815164a7b5..eb0cfc781ea5 100644
--- a/sys/sys/ktrace.h
+++ b/sys/sys/ktrace.h
@@ -54,7 +54,7 @@ struct ktr_header {
 	pid_t	ktr_pid;		/* process id */
 	char	ktr_comm[MAXCOMLEN+1];	/* command name */
 	struct	timeval ktr_time;	/* timestamp */
-	void	*ktr_buffer;
+	intptr_t	ktr_unused;	/* was ktr_buffer */
 };
 
 /*