Handle copyin failures.

Skip the log entry as there is nothing good to write out.  Don't fail
the syscall though since it already succeeded.  There's no reason
filemon's tracing failure should fail the already-succeeded syscall.

Record the error for later to return from close(2) on the filemon devfs
file descriptor.

Discussed with:	markj, sjg, kib (briefly with kib)
Reported by:	mjg
MFC after:	2 weeks
Sponsored by:	EMC / Isilon Storage Division

1 files changed, 39 insertions, 22 deletions

diff --git a/sys/dev/filemon/filemon_wrapper.c b/sys/dev/filemon/filemon_wrapper.c
index 58ede78..87c9392 100644
--- a/sys/dev/filemon/filemon_wrapper.c
+++ b/sys/dev/filemon/filemon_wrapper.c
@@ -72,21 +72,24 @@ filemon_output(struct filemon *filemon, char *msg, size_t len)
 static int
 filemon_wrapper_chdir(struct thread *td, struct chdir_args *uap)
 {
-	int ret;
+	int error, ret;
 	size_t len;
 	struct filemon *filemon;
 
 	if ((ret = sys_chdir(td, uap)) == 0) {
 		if ((filemon = filemon_proc_get(curproc)) != NULL) {
-			copyinstr(uap->path, filemon->fname1,
-			    sizeof(filemon->fname1), NULL);
+			if ((error = copyinstr(uap->path, filemon->fname1,
+			    sizeof(filemon->fname1), NULL)) != 0) {
+				filemon->error = error;
+				goto copyfail;
+			}
 
 			len = snprintf(filemon->msgbufr,
 			    sizeof(filemon->msgbufr), "C %d %s\n",
 			    curproc->p_pid, filemon->fname1);
 
 			filemon_output(filemon, filemon->msgbufr, len);
-
+copyfail:
 			filemon_drop(filemon);
 		}
 	}
@@ -123,6 +126,7 @@ filemon_event_process_exec(void *arg __unused, struct proc *p,
 static void
 _filemon_wrapper_openat(struct thread *td, char *upath, int flags, int fd)
 {
+	int error;
 	size_t len;
 	struct file *fp;
 	struct filemon *filemon;
@@ -134,8 +138,11 @@ _filemon_wrapper_openat(struct thread *td, char *upath, int flags, int fd)
 		freepath = NULL;
 		fp = NULL;
 
-		copyinstr(upath, filemon->fname1,
-		    sizeof(filemon->fname1), NULL);
+		if ((error = copyinstr(upath, filemon->fname1,
+		    sizeof(filemon->fname1), NULL)) != 0) {
+			filemon->error = error;
+			goto copyfail;
+		}
 
 		if (filemon->fname1[0] != '/' && fd != AT_FDCWD) {
 			/*
@@ -180,7 +187,7 @@ _filemon_wrapper_openat(struct thread *td, char *upath, int flags, int fd)
 		    curproc->p_pid, atpath,
 		    atpath[0] != '\0' ? "/" : "", filemon->fname1);
 		filemon_output(filemon, filemon->msgbufr, len);
-
+copyfail:
 		filemon_drop(filemon);
 		if (fp != NULL)
 			fdrop(fp, td);
@@ -213,23 +220,26 @@ filemon_wrapper_openat(struct thread *td, struct openat_args *uap)
 static int
 filemon_wrapper_rename(struct thread *td, struct rename_args *uap)
 {
-	int ret;
+	int error, ret;
 	size_t len;
 	struct filemon *filemon;
 
 	if ((ret = sys_rename(td, uap)) == 0) {
 		if ((filemon = filemon_proc_get(curproc)) != NULL) {
-			copyinstr(uap->from, filemon->fname1,
-			    sizeof(filemon->fname1), NULL);
-			copyinstr(uap->to, filemon->fname2,
-			    sizeof(filemon->fname2), NULL);
+			if (((error = copyinstr(uap->from, filemon->fname1,
+			     sizeof(filemon->fname1), NULL)) != 0) ||
+			    ((error = copyinstr(uap->to, filemon->fname2,
+			     sizeof(filemon->fname2), NULL)) != 0)) {
+				filemon->error = error;
+				goto copyfail;
+			}
 
 			len = snprintf(filemon->msgbufr,
 			    sizeof(filemon->msgbufr), "M %d '%s' '%s'\n",
 			    curproc->p_pid, filemon->fname1, filemon->fname2);
 
 			filemon_output(filemon, filemon->msgbufr, len);
-
+copyfail:
 			filemon_drop(filemon);
 		}
 	}
@@ -242,19 +252,23 @@ _filemon_wrapper_link(struct thread *td, char *upath1, char *upath2)
 {
 	struct filemon *filemon;
 	size_t len;
+	int error;
 
 	if ((filemon = filemon_proc_get(curproc)) != NULL) {
-		copyinstr(upath1, filemon->fname1,
-		    sizeof(filemon->fname1), NULL);
-		copyinstr(upath2, filemon->fname2,
-		    sizeof(filemon->fname2), NULL);
+		if (((error = copyinstr(upath1, filemon->fname1,
+		     sizeof(filemon->fname1), NULL)) != 0) ||
+		    ((error = copyinstr(upath2, filemon->fname2,
+		     sizeof(filemon->fname2), NULL)) != 0)) {
+			filemon->error = error;
+			goto copyfail;
+		}
 
 		len = snprintf(filemon->msgbufr,
 		    sizeof(filemon->msgbufr), "L %d '%s' '%s'\n",
 		    curproc->p_pid, filemon->fname1, filemon->fname2);
 
 		filemon_output(filemon, filemon->msgbufr, len);
-
+copyfail:
 		filemon_drop(filemon);
 	}
 }
@@ -322,21 +336,24 @@ filemon_event_process_exit(void *arg __unused, struct proc *p)
 static int
 filemon_wrapper_unlink(struct thread *td, struct unlink_args *uap)
 {
-	int ret;
+	int error, ret;
 	size_t len;
 	struct filemon *filemon;
 
 	if ((ret = sys_unlink(td, uap)) == 0) {
 		if ((filemon = filemon_proc_get(curproc)) != NULL) {
-			copyinstr(uap->path, filemon->fname1,
-			    sizeof(filemon->fname1), NULL);
+			if ((error = copyinstr(uap->path, filemon->fname1,
+			    sizeof(filemon->fname1), NULL)) != 0) {
+				filemon->error = error;
+				goto copyfail;
+			}
 
 			len = snprintf(filemon->msgbufr,
 			    sizeof(filemon->msgbufr), "D %d %s\n",
 			    curproc->p_pid, filemon->fname1);
 
 			filemon_output(filemon, filemon->msgbufr, len);
-
+copyfail:
 			filemon_drop(filemon);
 		}
 	}