This patch adds a new ktrace(2) record type, KTR_STRUCT, whose payload

consists of the null-terminated name and the contents of any structure
you wish to record.  A new ktrstruct() function constructs and emits a
KTR_STRUCT record.  It is accompanied by convenience macros for struct
stat and struct sockaddr.

In kdump(1), KTR_STRUCT records are handled by a dispatcher function
that runs stringent sanity checks on its contents before handing it
over to individual decoding funtions for each type of structure.
Currently supported structures are struct stat and struct sockaddr for
the AF_INET, AF_INET6 and AF_UNIX families; support for AF_APPLETALK
and AF_IPX is present but disabled, as I am unable to test it properly.

Since 's' was already taken, the letter 't' is used by ktrace(1) to
enable KTR_STRUCT trace points, and in kdump(1) to enable their
decoding.

Derived from patches by Andrew Li <andrew2.li@citi.com>.

PR:		kern/117836
MFC after:	3 weeks

5 files changed, 100 insertions, 1 deletions

diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index 27a5289..7025587 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
 
 #include "opt_compat.h"
 #include "opt_ddb.h"
+#include "opt_ktrace.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -72,6 +73,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/unistd.h>
 #include <sys/user.h>
 #include <sys/vnode.h>
+#ifdef KTRACE
+#include <sys/ktrace.h>
+#endif
 
 #include <security/audit/audit.h>
 
@@ -1126,6 +1130,10 @@ kern_fstat(struct thread *td, int fd, struct stat *sbp)
 
 	error = fo_stat(fp, sbp, td->td_ucred, td);
 	fdrop(fp, td);
+#ifdef KTRACE
+	if (error == 0 && KTRPOINT(td, KTR_STRUCT))
+		ktrstat(sbp);
+#endif
 	return (error);
 }
 
diff --git a/sys/kern/kern_ktrace.c b/sys/kern/kern_ktrace.c
index f5385ea..c8e4451 100644
--- a/sys/kern/kern_ktrace.c
+++ b/sys/kern/kern_ktrace.c
@@ -51,6 +51,8 @@ __FBSDID("$FreeBSD$");
 #include <sys/proc.h>
 #include <sys/unistd.h>
 #include <sys/vnode.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
 #include <sys/ktrace.h>
 #include <sys/sx.h>
 #include <sys/sysctl.h>
@@ -107,7 +109,8 @@ static int data_lengths[] = {
 	sizeof(struct ktr_genio),		/* KTR_GENIO */
 	sizeof(struct ktr_psig),		/* KTR_PSIG */
 	sizeof(struct ktr_csw),			/* KTR_CSW */
-	0					/* KTR_USER */
+	0,					/* KTR_USER */
+	0,					/* KTR_STRUCT */
 };
 
 static STAILQ_HEAD(, ktr_request) ktr_free;
@@ -552,6 +555,33 @@ ktrcsw(out, user)
 	kc->user = user;
 	ktr_enqueuerequest(curthread, req);
 }
+
+void
+ktrstruct(name, namelen, data, datalen)
+	const char *name;
+	size_t namelen;
+	void *data;
+	size_t datalen;
+{
+	struct ktr_request *req;
+	char *buf = NULL;
+	size_t buflen;
+
+	if (!data)
+		datalen = 0;
+	buflen = namelen + 1 + datalen;
+	buf = malloc(buflen, M_KTRACE, M_WAITOK);
+	bcopy(name, buf, namelen);
+	buf[namelen] = '\0';
+	bcopy(data, buf + namelen + 1, datalen);
+	if ((req = ktr_getrequest(KTR_STRUCT)) == NULL) {
+		free(buf, M_KTRACE);
+		return;
+	}
+	req->ktr_buffer = buf;
+	req->ktr_header.ktr_len = buflen;
+	ktr_submitrequest(curthread, req);
+}
 #endif /* KTRACE */
 
 /* Interface and common routines */
diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c
index 9709376..48e3bec 100644
--- a/sys/kern/uipc_syscalls.c
+++ b/sys/kern/uipc_syscalls.c
@@ -222,6 +222,10 @@ kern_bind(td, fd, sa)
 	if (error)
 		return (error);
 	so = fp->f_data;
+#ifdef KTRACE
+	if (KTRPOINT(td, KTR_STRUCT))
+		ktrsockaddr(sa);
+#endif
 #ifdef MAC
 	SOCK_LOCK(so);
 	error = mac_socket_check_bind(td->td_ucred, so, sa);
@@ -444,6 +448,10 @@ kern_accept(struct thread *td, int s, struct sockaddr **name,
 		/* check sa_len before it is destroyed */
 		if (*namelen > sa->sa_len)
 			*namelen = sa->sa_len;
+#ifdef KTRACE
+		if (KTRPOINT(td, KTR_STRUCT))
+			ktrsockaddr(sa);
+#endif
 		*name = sa;
 		sa = NULL;
 	}
@@ -538,6 +546,10 @@ kern_connect(td, fd, sa)
 		error = EALREADY;
 		goto done1;
 	}
+#ifdef KTRACE
+	if (KTRPOINT(td, KTR_STRUCT))
+		ktrsockaddr(sa);
+#endif
 #ifdef MAC
 	SOCK_LOCK(so);
 	error = mac_socket_check_connect(td->td_ucred, so, sa);
@@ -1052,6 +1064,10 @@ kern_recvit(td, s, mp, fromseg, controlp)
 	}
 out:
 	fdrop(fp, td);
+#ifdef KTRACE
+	if (fromsa && KTRPOINT(td, KTR_STRUCT))
+		ktrsockaddr(fromsa);
+#endif
 	if (fromsa)
 		FREE(fromsa, M_SONAME);
 
@@ -1456,6 +1472,10 @@ kern_getsockname(struct thread *td, int fd, struct sockaddr **sa,
 	else
 		len = MIN(*alen, (*sa)->sa_len);
 	*alen = len;
+#ifdef KTRACE
+	if (KTRPOINT(td, KTR_STRUCT))
+		ktrsockaddr(*sa);
+#endif
 bad:
 	fdrop(fp, td);
 	if (error && *sa) {
@@ -1553,6 +1573,10 @@ kern_getpeername(struct thread *td, int fd, struct sockaddr **sa,
 	else
 		len = MIN(*alen, (*sa)->sa_len);
 	*alen = len;
+#ifdef KTRACE
+	if (KTRPOINT(td, KTR_STRUCT))
+		ktrsockaddr(*sa);
+#endif
 bad:
 	if (error && *sa) {
 		free(*sa, M_SONAME);
@@ -2373,6 +2397,10 @@ sctp_generic_sendmsg (td, uap)
 	error = getsock(td->td_proc->p_fd, uap->sd, &fp, NULL);
 	if (error)
 		goto sctp_bad;
+#ifdef KTRACE
+	if (KTRPOINT(td, KTR_STRUCT))
+		ktrsockaddr(to);
+#endif
 
 	iov[0].iov_base = uap->msg;
 	iov[0].iov_len = uap->mlen;
@@ -2476,6 +2504,10 @@ sctp_generic_sendmsg_iov(td, uap)
 	error = copyiniov(uap->iov, uap->iovlen, &iov, EMSGSIZE);
 	if (error)
 		goto sctp_bad1;
+#ifdef KTRACE
+	if (KTRPOINT(td, KTR_STRUCT))
+		ktrsockaddr(to);
+#endif
 
 	so = (struct socket *)fp->f_data;
 #ifdef MAC
@@ -2659,6 +2691,10 @@ sctp_generic_recvmsg(td, uap)
 			goto out;
 		}
 	}
+#ifdef KTRACE
+	if (KTRPOINT(td, KTR_STRUCT))
+		ktrsockaddr(fromsa);
+#endif
 	if (uap->msg_flags) {
 		error = copyout(&msg_flags, uap->msg_flags, sizeof (int));
 		if (error) {
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index d05ca3a..8829a9c 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -38,6 +38,7 @@
 __FBSDID("$FreeBSD$");
 
 #include "opt_compat.h"
+#include "opt_ktrace.h"
 #include "opt_mac.h"
 
 #include <sys/param.h>
@@ -67,6 +68,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/jail.h>
 #include <sys/syscallsubr.h>
 #include <sys/sysctl.h>
+#ifdef KTRACE
+#include <sys/ktrace.h>
+#endif
 
 #include <machine/stdarg.h>
 
@@ -2120,6 +2124,10 @@ kern_stat(struct thread *td, char *path, enum uio_seg pathseg, struct stat *sbp)
 	if (error)
 		return (error);
 	*sbp = sb;
+#ifdef KTRACE
+	if (KTRPOINT(td, KTR_STRUCT))
+		ktrstat(&sb);
+#endif
 	return (0);
 }
 
@@ -2171,6 +2179,10 @@ kern_lstat(struct thread *td, char *path, enum uio_seg pathseg, struct stat *sbp
 	if (error)
 		return (error);
 	*sbp = sb;
+#ifdef KTRACE
+	if (KTRPOINT(td, KTR_STRUCT))
+		ktrstat(&sb);
+#endif
 	return (0);
 }
 
diff --git a/sys/sys/ktrace.h b/sys/sys/ktrace.h
index 4572141..cf9f977 100644
--- a/sys/sys/ktrace.h
+++ b/sys/sys/ktrace.h
@@ -151,6 +151,13 @@ struct ktr_csw {
 #define KTR_USER	7
 
 /*
+ * KTR_STRUCT - misc. structs
+ */
+#define KTR_STRUCT	8
+struct sockaddr;
+struct stat;
+
+/*
  * KTR_DROP - If this bit is set in ktr_type, then at least one event
  * between the previous record and this record was dropped.
  */
@@ -167,6 +174,7 @@ struct ktr_csw {
 #define	KTRFAC_PSIG	(1<<KTR_PSIG)
 #define KTRFAC_CSW	(1<<KTR_CSW)
 #define KTRFAC_USER	(1<<KTR_USER)
+#define KTRFAC_STRUCT	(1<<KTR_STRUCT)
 /*
  * trace flags (also in p_traceflags)
  */
@@ -185,6 +193,11 @@ void	ktrsyscall(int, int narg, register_t args[]);
 void	ktrsysret(int, int, register_t);
 void	ktrprocexit(struct thread *);
 void	ktruserret(struct thread *);
+void	ktrstruct(const char *, size_t, void *, size_t);
+#define ktrsockaddr(s) \
+	ktrstruct("sockaddr", 8, (s), ((struct sockaddr *)(s))->sa_len)
+#define ktrstat(s) \
+	ktrstruct("stat", 4, (s), sizeof(struct stat))
 
 #else