- >500 static DTrace probes for the linuxulator

- DTrace scripts to check for errors, performance, ...
  they serve mostly as examples of what you can do with the static probe;s
  with moderate load the scripts may be overwhelmed, excessive lock-tracing
  may influence program behavior (see the last design decission)

Design decissions:
 - use "linuxulator" as the provider for the native bitsize; add the
   bitsize for the non-native emulation (e.g. "linuxuator32" on amd64)
 - Add probes only for locks which are acquired in one function and released
   in another function. Locks which are aquired and released in the same
   function should be easy to pair in the code, inter-function
   locking is more easy to verify in DTrace.
 - Probes for locks should be fired after locking and before releasing to
   prevent races (to provide data/function stability in DTrace, see the
   man-page of "dtrace -v ..." and the corresponding DTrace docs).

1 files changed, 161 insertions, 28 deletions

diff --git a/sys/compat/linux/linux_uid16.c b/sys/compat/linux/linux_uid16.c
index 31950ff..b66fb5c 100644
--- a/sys/compat/linux/linux_uid16.c
+++ b/sys/compat/linux/linux_uid16.c
@@ -28,14 +28,17 @@
 __FBSDID("$FreeBSD$");
 
 #include "opt_compat.h"
+#include "opt_kdtrace.h"
 
 #include <sys/fcntl.h>
 #include <sys/param.h>
+#include <sys/kernel.h>
 #include <sys/lock.h>
 #include <sys/malloc.h>
 #include <sys/mutex.h>
 #include <sys/priv.h>
 #include <sys/proc.h>
+#include <sys/sdt.h>
 #include <sys/syscallsubr.h>
 #include <sys/sysproto.h>
 #include <sys/systm.h>
@@ -48,8 +51,53 @@ __FBSDID("$FreeBSD$");
 #include <machine/../linux/linux_proto.h>
 #endif
 
+#include <compat/linux/linux_dtrace.h>
 #include <compat/linux/linux_util.h>
 
+/* DTrace init */
+LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
+
+/**
+ * DTrace probes in this module.
+ */
+LIN_SDT_PROBE_DEFINE3(uid16, linux_chown16, entry, "char *", "l_uid16_t",
+    "l_gid16_t");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_chown16, conv_path, "char *");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_chown16, return, "int");
+LIN_SDT_PROBE_DEFINE3(uid16, linux_lchown16, entry, "char *", "l_uid16_t",
+    "l_gid16_t");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_lchown16, conv_path, "char *");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_lchown16, return, "int");
+LIN_SDT_PROBE_DEFINE2(uid16, linux_setgroups16, entry, "l_uint", "l_gid16_t *");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setgroups16, copyin_error, "int");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setgroups16, priv_check_cred_error, "int");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setgroups16, return, "int");
+LIN_SDT_PROBE_DEFINE2(uid16, linux_getgroups16, entry, "l_uint", "l_gid16_t *");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_getgroups16, copyout_error, "int");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_getgroups16, return, "int");
+LIN_SDT_PROBE_DEFINE0(uid16, linux_getgid16, entry);
+LIN_SDT_PROBE_DEFINE1(uid16, linux_getgid16, return, "int");
+LIN_SDT_PROBE_DEFINE0(uid16, linux_getuid16, entry);
+LIN_SDT_PROBE_DEFINE1(uid16, linux_getuid16, return, "int");
+LIN_SDT_PROBE_DEFINE0(uid16, linux_getegid16, entry);
+LIN_SDT_PROBE_DEFINE1(uid16, linux_getegid16, return, "int");
+LIN_SDT_PROBE_DEFINE0(uid16, linux_geteuid16, entry);
+LIN_SDT_PROBE_DEFINE1(uid16, linux_geteuid16, return, "int");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setgid16, entry, "l_gid16_t");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setgid16, return, "int");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setuid16, entry, "l_uid16_t");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setuid16, return, "int");
+LIN_SDT_PROBE_DEFINE2(uid16, linux_setregid16, entry, "l_git16_t", "l_git16_t");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setregid16, return, "int");
+LIN_SDT_PROBE_DEFINE2(uid16, linux_setreuid16, entry, "l_uid16_t", "l_uid16_t");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setreuid16, return, "int");
+LIN_SDT_PROBE_DEFINE3(uid16, linux_setresgid16, entry, "l_gid16_t", "l_gid16_t",
+    "l_gid16_t");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setresgid16, return, "int");
+LIN_SDT_PROBE_DEFINE3(uid16, linux_setresuid16, entry, "l_uid16_t", "l_uid16_t",
+    "l_uid16_t");
+LIN_SDT_PROBE_DEFINE1(uid16, linux_setresuid16, return, "int");
+
 DUMMY(setfsuid16);
 DUMMY(setfsgid16);
 DUMMY(getresuid16);
@@ -65,13 +113,20 @@ linux_chown16(struct thread *td, struct linux_chown16_args *args)
 
 	LCONVPATHEXIST(td, args->path, &path);
 
-#ifdef DEBUG
-	if (ldebug(chown16))
-		printf(ARGS(chown16, "%s, %d, %d"), path, args->uid, args->gid);
-#endif
+	/*
+	 * The DTrace probes have to be after the LCONVPATHEXIST, as
+	 * LCONVPATHEXIST may return on its own and we do not want to
+	 * have a stray entry without the corresponding return.
+	 */
+	LIN_SDT_PROBE3(uid16, linux_chown16, entry, args->path, args->uid,
+	    args->gid);
+	LIN_SDT_PROBE1(uid16, linux_chown16, conv_path, path);
+
 	error = kern_chown(td, path, UIO_SYSSPACE, CAST_NOCHG(args->uid),
 	    CAST_NOCHG(args->gid));
 	LFREEPATH(path);
+
+	LIN_SDT_PROBE1(uid16, linux_chown16, return, error);
 	return (error);
 }
 
@@ -83,14 +138,20 @@ linux_lchown16(struct thread *td, struct linux_lchown16_args *args)
 
 	LCONVPATHEXIST(td, args->path, &path);
 
-#ifdef DEBUG
-	if (ldebug(lchown16))
-		printf(ARGS(lchown16, "%s, %d, %d"), path, args->uid,
-		    args->gid);
-#endif
+	/*
+	 * The DTrace probes have to be after the LCONVPATHEXIST, as
+	 * LCONVPATHEXIST may return on its own and we do not want to
+	 * have a stray entry without the corresponding return.
+	 */
+	LIN_SDT_PROBE3(uid16, linux_lchown16, entry, args->path, args->uid,
+	    args->gid);
+	LIN_SDT_PROBE1(uid16, linux_lchown16, conv_path, path);
+
 	error = kern_lchown(td, path, UIO_SYSSPACE, CAST_NOCHG(args->uid),
 	    CAST_NOCHG(args->gid));
 	LFREEPATH(path);
+
+	LIN_SDT_PROBE1(uid16, linux_lchown16, return, error);
 	return (error);
 }
 
@@ -103,17 +164,19 @@ linux_setgroups16(struct thread *td, struct linux_setgroups16_args *args)
 	int ngrp, error;
 	struct proc *p;
 
-#ifdef DEBUG
-	if (ldebug(setgroups16))
-		printf(ARGS(setgroups16, "%d, *"), args->gidsetsize);
-#endif
+	LIN_SDT_PROBE2(uid16, linux_setgroups16, entry, args->gidsetsize,
+	    args->gidset);
 
 	ngrp = args->gidsetsize;
-	if (ngrp < 0 || ngrp >= ngroups_max + 1)
+	if (ngrp < 0 || ngrp >= ngroups_max + 1) {
+		LIN_SDT_PROBE1(uid16, linux_setgroups16, return, EINVAL);
 		return (EINVAL);
+	}
 	linux_gidset = malloc(ngrp * sizeof(*linux_gidset), M_TEMP, M_WAITOK);
 	error = copyin(args->gidset, linux_gidset, ngrp * sizeof(l_gid16_t));
 	if (error) {
+		LIN_SDT_PROBE1(uid16, linux_setgroups16, copyin_error, error);
+		LIN_SDT_PROBE1(uid16, linux_setgroups16, return, error);
 		free(linux_gidset, M_TEMP);
 		return (error);
 	}
@@ -131,6 +194,9 @@ linux_setgroups16(struct thread *td, struct linux_setgroups16_args *args)
 	if ((error = priv_check_cred(oldcred, PRIV_CRED_SETGROUPS, 0)) != 0) {
 		PROC_UNLOCK(p);
 		crfree(newcred);
+
+		LIN_SDT_PROBE1(uid16, linux_setgroups16, priv_check_cred_error,
+		    error);
 		goto out;
 	}
 
@@ -154,6 +220,8 @@ linux_setgroups16(struct thread *td, struct linux_setgroups16_args *args)
 	error = 0;
 out:
 	free(linux_gidset, M_TEMP);
+
+	LIN_SDT_PROBE1(uid16, linux_setgroups16, return, error);
 	return (error);
 }
 
@@ -165,10 +233,8 @@ linux_getgroups16(struct thread *td, struct linux_getgroups16_args *args)
 	gid_t *bsd_gidset;
 	int bsd_gidsetsz, ngrp, error;
 
-#ifdef DEBUG
-	if (ldebug(getgroups16))
-		printf(ARGS(getgroups16, "%d, *"), args->gidsetsize);
-#endif
+	LIN_SDT_PROBE2(uid16, linux_getgroups16, entry, args->gidsetsize,
+	    args->gidset);
 
 	cred = td->td_ucred;
 	bsd_gidset = cred->cr_groups;
@@ -182,11 +248,15 @@ linux_getgroups16(struct thread *td, struct linux_getgroups16_args *args)
 
 	if ((ngrp = args->gidsetsize) == 0) {
 		td->td_retval[0] = bsd_gidsetsz;
+
+		LIN_SDT_PROBE1(uid16, linux_getgroups16, return, 0);
 		return (0);
 	}
 
-	if (ngrp < bsd_gidsetsz)
+	if (ngrp < bsd_gidsetsz) {
+		LIN_SDT_PROBE1(uid16, linux_getgroups16, return, EINVAL);
 		return (EINVAL);
+	}
 
 	ngrp = 0;
 	linux_gidset = malloc(bsd_gidsetsz * sizeof(*linux_gidset),
@@ -198,10 +268,15 @@ linux_getgroups16(struct thread *td, struct linux_getgroups16_args *args)
 
 	error = copyout(linux_gidset, args->gidset, ngrp * sizeof(l_gid16_t));
 	free(linux_gidset, M_TEMP);
-	if (error)
+	if (error) {
+		LIN_SDT_PROBE1(uid16, linux_getgroups16, copyout_error, error);
+		LIN_SDT_PROBE1(uid16, linux_getgroups16, return, error);
 		return (error);
+	}
 
 	td->td_retval[0] = ngrp;
+
+	LIN_SDT_PROBE1(uid16, linux_getgroups16, return, 0);
 	return (0);
 }
 
@@ -219,7 +294,11 @@ int
 linux_getgid16(struct thread *td, struct linux_getgid16_args *args)
 {
 
+	LIN_SDT_PROBE0(uid16, linux_getgid16, entry);
+
 	td->td_retval[0] = td->td_ucred->cr_rgid;
+
+	LIN_SDT_PROBE1(uid16, linux_getgid16, return, 0);
 	return (0);
 }
 
@@ -227,7 +306,11 @@ int
 linux_getuid16(struct thread *td, struct linux_getuid16_args *args)
 {
 
+	LIN_SDT_PROBE0(uid16, linux_getuid16, entry);
+
 	td->td_retval[0] = td->td_ucred->cr_ruid;
+
+	LIN_SDT_PROBE1(uid16, linux_getuid16, return, 0);
 	return (0);
 }
 
@@ -235,74 +318,124 @@ int
 linux_getegid16(struct thread *td, struct linux_getegid16_args *args)
 {
 	struct getegid_args bsd;
+	int error;
+
+	LIN_SDT_PROBE0(uid16, linux_getegid16, entry);
+
+	error = sys_getegid(td, &bsd);
 
-	return (sys_getegid(td, &bsd));
+	LIN_SDT_PROBE1(uid16, linux_getegid16, return, error);
+	return (error);
 }
 
 int
 linux_geteuid16(struct thread *td, struct linux_geteuid16_args *args)
 {
 	struct geteuid_args bsd;
+	int error;
+
+	LIN_SDT_PROBE0(uid16, linux_geteuid16, entry);
+
+	error = sys_geteuid(td, &bsd);
 
-	return (sys_geteuid(td, &bsd));
+	LIN_SDT_PROBE1(uid16, linux_geteuid16, return, error);
+	return (error);
 }
 
 int
 linux_setgid16(struct thread *td, struct linux_setgid16_args *args)
 {
 	struct setgid_args bsd;
+	int error;
+
+	LIN_SDT_PROBE1(uid16, linux_setgid16, entry, args->gid);
 
 	bsd.gid = args->gid;
-	return (sys_setgid(td, &bsd));
+	error = sys_setgid(td, &bsd);
+
+	LIN_SDT_PROBE1(uid16, linux_setgid16, return, error);
+	return (error);
 }
 
 int
 linux_setuid16(struct thread *td, struct linux_setuid16_args *args)
 {
 	struct setuid_args bsd;
+	int error;
+
+	LIN_SDT_PROBE1(uid16, linux_setuid16, entry, args->uid);
 
 	bsd.uid = args->uid;
-	return (sys_setuid(td, &bsd));
+	error = sys_setuid(td, &bsd);
+
+	LIN_SDT_PROBE1(uid16, linux_setuid16, return, error);
+	return (error);
 }
 
 int
 linux_setregid16(struct thread *td, struct linux_setregid16_args *args)
 {
 	struct setregid_args bsd;
+	int error;
+
+	LIN_SDT_PROBE2(uid16, linux_setregid16, entry, args->rgid, args->egid);
 
 	bsd.rgid = CAST_NOCHG(args->rgid);
 	bsd.egid = CAST_NOCHG(args->egid);
-	return (sys_setregid(td, &bsd));
+	error = sys_setregid(td, &bsd);
+
+	LIN_SDT_PROBE1(uid16, linux_setregid16, return, error);
+	return (error);
 }
 
 int
 linux_setreuid16(struct thread *td, struct linux_setreuid16_args *args)
 {
 	struct setreuid_args bsd;
+	int error;
+
+	LIN_SDT_PROBE2(uid16, linux_setreuid16, entry, args->ruid, args->euid);
 
 	bsd.ruid = CAST_NOCHG(args->ruid);
 	bsd.euid = CAST_NOCHG(args->euid);
-	return (sys_setreuid(td, &bsd));
+	error = sys_setreuid(td, &bsd);
+
+	LIN_SDT_PROBE1(uid16, linux_setreuid16, return, error);
+	return (error);
 }
 
 int
 linux_setresgid16(struct thread *td, struct linux_setresgid16_args *args)
 {
 	struct setresgid_args bsd;
+	int error;
+
+	LIN_SDT_PROBE3(uid16, linux_setresgid16, entry, args->rgid, args->egid,
+	    args->sgid);
 
 	bsd.rgid = CAST_NOCHG(args->rgid);
 	bsd.egid = CAST_NOCHG(args->egid);
 	bsd.sgid = CAST_NOCHG(args->sgid);
-	return (sys_setresgid(td, &bsd));
+	error = sys_setresgid(td, &bsd);
+
+	LIN_SDT_PROBE1(uid16, linux_setresgid16, return, error);
+	return (error);
 }
 
 int
 linux_setresuid16(struct thread *td, struct linux_setresuid16_args *args)
 {
 	struct setresuid_args bsd;
+	int error;
+
+	LIN_SDT_PROBE3(uid16, linux_setresuid16, entry, args->ruid, args->euid,
+	    args->suid);
 
 	bsd.ruid = CAST_NOCHG(args->ruid);
 	bsd.euid = CAST_NOCHG(args->euid);
 	bsd.suid = CAST_NOCHG(args->suid);
-	return (sys_setresuid(td, &bsd));
+	error = sys_setresuid(td, &bsd);
+
+	LIN_SDT_PROBE1(uid16, linux_setresuid16, return, error);
+	return (error);
 }