Index: share/man/man9/vn_fullpath.9
===================================================================
--- share/man/man9/vn_fullpath.9
+++ share/man/man9/vn_fullpath.9
@@ -27,7 +27,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 23, 2008
+.Dd January 4, 2020
 .Dt VN_FULLPATH 9
 .Os
 .Sh NAME
@@ -38,7 +38,7 @@
 .In sys/vnode.h
 .Ft int
 .Fo vn_fullpath
-.Fa "struct thread *td" "struct vnode *vp" "char **retbuf" "char **freebuf"
+.Fa "struct thread *td" "struct vnode *vp" "const char **retbuf" "char **freebuf"
 .Fc
 .Sh DESCRIPTION
 The
@@ -77,7 +77,7 @@
 No need to be locked by the caller.
 .It Fa retbuf
 Pointer to a
-.Vt "char *"
+.Vt "const char *"
 that
 .Fn vn_fullpath
 may (on success) point at a newly
Index: sys/compat/linprocfs/linprocfs.c
===================================================================
--- sys/compat/linprocfs/linprocfs.c
+++ sys/compat/linprocfs/linprocfs.c
@@ -418,8 +418,8 @@
 linprocfs_domtab(PFS_FILL_ARGS)
 {
 	struct nameidata nd;
-	const char *lep;
-	char *dlep, *flep, *mntto, *mntfrom, *fstype;
+	const char *dlep, *lep;
+	char *flep, *mntto, *mntfrom, *fstype;
 	size_t lep_len;
 	int error;
 	struct statfs *buf, *sp;
@@ -1030,7 +1030,7 @@
 {
 	struct filedesc *fdp;
 	struct vnode *vp;
-	char *fullpath = "unknown";
+	const char *fullpath = "unknown";
 	char *freepath = NULL;
 
 	fdp = p->p_fd;
@@ -1056,7 +1056,7 @@
 {
 	struct filedesc *fdp;
 	struct vnode *vp;
-	char *fullpath = "unknown";
+	const char *fullpath = "unknown";
 	char *freepath = NULL;
 
 	fdp = p->p_fd;
@@ -1149,7 +1149,8 @@
 	vm_ooffset_t off;
 	vm_prot_t e_prot;
 	unsigned int last_timestamp;
-	char *name = "", *freename = NULL;
+	char *freename = NULL;
+	const char *name = "";
 	const char *l_map_str;
 	ino_t ino;
 	int ref_count, shadow_count, flags;
Index: sys/compat/linux/linux_getcwd.c
===================================================================
--- sys/compat/linux/linux_getcwd.c
+++ sys/compat/linux/linux_getcwd.c
@@ -62,7 +62,8 @@
 int
 linux_getcwd(struct thread *td, struct linux_getcwd_args *uap)
 {
-	char *buf, *retbuf;
+	char *buf;
+	const char *retbuf;
 	size_t buflen;
 	int error;
 
Index: sys/dev/filemon/filemon_wrapper.c
===================================================================
--- sys/dev/filemon/filemon_wrapper.c
+++ sys/dev/filemon/filemon_wrapper.c
@@ -154,7 +154,8 @@
 	int error;
 	struct file *fp;
 	struct filemon *filemon;
-	char *atpath, *freepath;
+	const char *atpath;
+	char *freepath;
 	cap_rights_t rights;
 
 	if ((filemon = filemon_proc_get(curproc)) != NULL) {
Index: sys/dev/hwpmc/hwpmc_logging.c
===================================================================
--- sys/dev/hwpmc/hwpmc_logging.c
+++ sys/dev/hwpmc/hwpmc_logging.c
@@ -1023,7 +1023,7 @@
 }
 
 void
-pmclog_process_pmcattach(struct pmc *pm, pid_t pid, char *path)
+pmclog_process_pmcattach(struct pmc *pm, pid_t pid, const char *path)
 {
 	int pathlen, recordlen;
 	struct pmc_owner *po;
@@ -1103,7 +1103,7 @@
 
 void
 pmclog_process_procexec(struct pmc_owner *po, pmc_id_t pmid, pid_t pid,
-    uintfptr_t startaddr, char *path)
+    uintfptr_t startaddr, const char *path)
 {
 	int pathlen, recordlen;
 
Index: sys/dev/hwpmc/hwpmc_mod.c
===================================================================
--- sys/dev/hwpmc/hwpmc_mod.c
+++ sys/dev/hwpmc/hwpmc_mod.c
@@ -825,7 +825,7 @@
  */
 
 static void
-pmc_getfilename(struct vnode *v, char **fullpath, char **freepath)
+pmc_getfilename(struct vnode *v, const char **fullpath, char **freepath)
 {
 
 	*fullpath = "unknown";
@@ -1096,7 +1096,8 @@
 pmc_attach_one_process(struct proc *p, struct pmc *pm)
 {
 	int ri, error;
-	char *fullpath, *freepath;
+	const char *fullpath;
+	char *freepath;
 	struct pmc_process	*pp;
 
 	sx_assert(&pmc_sx, SX_XLOCKED);
@@ -1752,12 +1753,14 @@
 {
 	int ri;
 	pid_t pid;
-	char *fullpath, *freepath;
+	const char *fullpath;
+	char *freepath;
 	const struct pmc *pm;
 	struct pmc_owner *po;
 	const struct pmc_process *pp;
 
-	freepath = fullpath = NULL;
+	freepath = NULL;
+	fullpath = NULL;
 	MPASS(!in_epoch(global_epoch_preempt));
 	pmc_getfilename((struct vnode *) pkm->pm_file, &fullpath, &freepath);
 
@@ -1872,7 +1875,8 @@
 	struct vnode *last_vp;
 	vm_offset_t start_addr;
 	vm_object_t obj, lobj, tobj;
-	char *fullpath, *freepath;
+	const char *fullpath;
+	char *freepath;
 
 	last_vp = NULL;
 	last_end = (vm_offset_t) 0;
@@ -2096,7 +2100,8 @@
 
 	case PMC_FN_PROCESS_EXEC:
 	{
-		char *fullpath, *freepath;
+		const char *fullpath;
+		char *freepath;
 		unsigned int ri;
 		int is_using_hwpmcs;
 		struct pmc *pm;
Index: sys/fs/fdescfs/fdesc_vnops.c
===================================================================
--- sys/fs/fdescfs/fdesc_vnops.c
+++ sys/fs/fdescfs/fdesc_vnops.c
@@ -619,7 +619,8 @@
 	struct thread *td;
 	struct uio *uio;
 	struct file *fp;
-	char *freepath, *fullpath;
+	const char *fullpath;
+	char *freepath;
 	size_t pathlen;
 	int lockflags, fd_fd;
 	int error;
@@ -649,7 +650,8 @@
 	if (error == 0) {
 		uio = va->a_uio;
 		pathlen = strlen(fullpath);
-		error = uiomove(fullpath, pathlen, uio);
+		/* uiomove will only copyout in this context. */
+		error = uiomove(__DECONST(char *, fullpath), pathlen, uio);
 	}
 	if (freepath != NULL)
 		free(freepath, M_TEMP);
Index: sys/fs/procfs/procfs.c
===================================================================
--- sys/fs/procfs/procfs.c
+++ sys/fs/procfs/procfs.c
@@ -69,7 +69,7 @@
 int
 procfs_doprocfile(PFS_FILL_ARGS)
 {
-	char *fullpath;
+	const char *fullpath;
 	char *freepath;
 	struct vnode *textvp;
 	int error;
Index: sys/fs/procfs/procfs_map.c
===================================================================
--- sys/fs/procfs/procfs_map.c
+++ sys/fs/procfs/procfs_map.c
@@ -82,7 +82,8 @@
 	vm_map_t map;
 	vm_map_entry_t entry, tmp_entry;
 	struct vnode *vp;
-	char *fullpath, *freepath, *type;
+	const char *fullpath;
+	char *freepath, *type;
 	struct ucred *cred;
 	vm_object_t obj, tobj, lobj;
 	int error, privateresident, ref_count, resident, shadow_count, flags;
Index: sys/kern/kern_ktrace.c
===================================================================
--- sys/kern/kern_ktrace.c
+++ sys/kern/kern_ktrace.c
@@ -618,7 +618,7 @@
 
 void
 ktrnamei(path)
-	char *path;
+	const char *path;
 {
 	struct ktr_request *req;
 	int namelen;
Index: sys/kern/kern_proc.c
===================================================================
--- sys/kern/kern_proc.c
+++ sys/kern/kern_proc.c
@@ -2153,7 +2153,8 @@
 	unsigned int arglen = arg2;
 	struct proc *p;
 	struct vnode *vp;
-	char *retbuf, *freebuf;
+	char *freebuf;
+	const char *retbuf;
 	int error;
 
 	if (arglen != 1)
@@ -2216,7 +2217,8 @@
 {
 	vm_map_entry_t entry, tmp_entry;
 	unsigned int last_timestamp;
-	char *fullpath, *freepath;
+	const char *fullpath;
+	char *freepath;
 	struct kinfo_ovmentry *kve;
 	struct vattr va;
 	struct ucred *cred;
@@ -2428,7 +2430,8 @@
 	struct vattr va;
 	vm_map_t map;
 	vm_object_t obj, tobj, lobj;
-	char *fullpath, *freepath;
+	const char *fullpath;
+	char *freepath;
 	struct kinfo_vmentry *kve;
 	struct ucred *cred;
 	struct vnode *vp;
Index: sys/kern/kern_sig.c
===================================================================
--- sys/kern/kern_sig.c
+++ sys/kern/kern_sig.c
@@ -3657,7 +3657,8 @@
 	char *name;			/* name of corefile */
 	void *rl_cookie;
 	off_t limit;
-	char *fullpath, *freepath = NULL;
+	const char *fullpath;
+	char *freepath = NULL;
 	struct sbuf *sb;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
Index: sys/kern/sys_process.c
===================================================================
--- sys/kern/sys_process.c
+++ sys/kern/sys_process.c
@@ -370,7 +370,8 @@
 	vm_object_t obj, tobj, lobj;
 	struct vmspace *vm;
 	struct vnode *vp;
-	char *freepath, *fullpath;
+	const char *fullpath;
+	char *freepath;
 	u_int pathlen;
 	int error, index;
 
Index: sys/kern/vfs_cache.c
===================================================================
--- sys/kern/vfs_cache.c
+++ sys/kern/vfs_cache.c
@@ -388,12 +388,12 @@
     "Number of times shrinking was already in progress");
 
 static void cache_zap_locked(struct namecache *ncp, bool neg_locked);
-static int vn_fullpath_hardlink(struct thread *td, struct nameidata *ndp, char **retbuf,
-    char **freebuf, size_t *buflen);
+static int vn_fullpath_hardlink(struct thread *td, struct nameidata *ndp,
+    const char **retbuf, char **freebuf, size_t *buflen);
 static int vn_fullpath_any(struct thread *td, struct vnode *vp, struct vnode *rdir,
-    char *buf, char **retbuf, size_t *buflen);
+    char *buf, const char **retbuf, size_t *buflen);
 static int vn_fullpath_dir(struct thread *td, struct vnode *vp, struct vnode *rdir,
-    char *buf, char **retbuf, size_t *len, bool slash_prefixed, size_t addend);
+    char *buf, const char **retbuf, size_t *len, bool slash_prefixed, size_t addend);
 
 static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries");
 
@@ -2174,7 +2174,8 @@
 int
 sys___getcwd(struct thread *td, struct __getcwd_args *uap)
 {
-	char *buf, *retbuf;
+	char *buf;
+	const char *retbuf;
 	size_t buflen;
 	int error;
 
@@ -2193,7 +2194,7 @@
 }
 
 int
-vn_getcwd(struct thread *td, char *buf, char **retbuf, size_t *buflen)
+vn_getcwd(struct thread *td, char *buf, const char **retbuf, size_t *buflen)
 {
 	struct filedesc *fdp;
 	struct vnode *cdir, *rdir;
@@ -2222,7 +2223,8 @@
     size_t size, int flags, enum uio_seg pathseg)
 {
 	struct nameidata nd;
-	char *retbuf, *freebuf;
+	const char *retbuf;
+	char *freebuf;
 	int error;
 
 	if (flags != 0)
@@ -2253,7 +2255,8 @@
  * cache (if available)
  */
 int
-vn_fullpath(struct thread *td, struct vnode *vn, char **retbuf, char **freebuf)
+vn_fullpath(struct thread *td, struct vnode *vn, const char **retbuf,
+    char **freebuf)
 {
 	char *buf;
 	struct filedesc *fdp;
@@ -2289,7 +2292,7 @@
  */
 int
 vn_fullpath_global(struct thread *td, struct vnode *vn,
-    char **retbuf, char **freebuf)
+    const char **retbuf, char **freebuf)
 {
 	char *buf;
 	size_t buflen;
@@ -2380,7 +2383,8 @@
  */
 static int
 vn_fullpath_dir(struct thread *td, struct vnode *vp, struct vnode *rdir,
-    char *buf, char **retbuf, size_t *len, bool slash_prefixed, size_t addend)
+    char *buf, const char **retbuf, size_t *len, bool slash_prefixed,
+    size_t addend)
 {
 #ifdef KDTRACE_HOOKS
 	struct vnode *startvp = vp;
@@ -2491,7 +2495,7 @@
  */
 static int
 vn_fullpath_any(struct thread *td, struct vnode *vp, struct vnode *rdir,
-    char *buf, char **retbuf, size_t *buflen)
+    char *buf, const char **retbuf, size_t *buflen)
 {
 	size_t orig_buflen;
 	bool slash_prefixed;
@@ -2536,8 +2540,8 @@
  *   from the parent
  */
 static int
-vn_fullpath_hardlink(struct thread *td, struct nameidata *ndp, char **retbuf,
-    char **freebuf, size_t *buflen)
+vn_fullpath_hardlink(struct thread *td, struct nameidata *ndp,
+    const char **retbuf, char **freebuf, size_t *buflen)
 {
 	char *buf, *tmpbuf;
 	struct filedesc *fdp;
@@ -2659,7 +2663,8 @@
 {
 	struct nameidata nd;
 	struct vnode *vp1;
-	char *rpath, *fbuf;
+	const char *rpath;
+	char *fbuf;
 	int error;
 
 	ASSERT_VOP_ELOCKED(vp, __func__);
Index: sys/kern/vfs_vnops.c
===================================================================
--- sys/kern/vfs_vnops.c
+++ sys/kern/vfs_vnops.c
@@ -2404,7 +2404,8 @@
 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif)
 {
 	struct vattr va;
-	char *fullpath, *freepath;
+	const char *fullpath;
+	char *freepath;
 	int error;
 
 	kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type);
Index: sys/security/audit/audit_bsm_klib.c
===================================================================
--- sys/security/audit/audit_bsm_klib.c
+++ sys/security/audit/audit_bsm_klib.c
@@ -425,7 +425,8 @@
     char *path, char *cpath)
 {
 	struct vnode *vp;
-	char *rbuf, *fbuf, *copy;
+	char *fbuf, *copy;
+	const char *rbuf;
 	struct sbuf sbf;
 	int error;
 
Index: sys/sys/imgact.h
===================================================================
--- sys/sys/imgact.h
+++ sys/sys/imgact.h
@@ -78,7 +78,7 @@
 	unsigned long ps_strings; /* PS_STRINGS for BSD/OS binaries */
 	struct image_args *args;	/* system call arguments */
 	struct sysentvec *sysent;	/* system entry vector */
-	char *execpath;
+	const char *execpath;
 	unsigned long execpathp;
 	char *freepath;
 	unsigned long canary;
Index: sys/sys/ktrace.h
===================================================================
--- sys/sys/ktrace.h
+++ sys/sys/ktrace.h
@@ -265,7 +265,7 @@
 #define	KTRFAC_DROP	0x20000000	/* last event was dropped */
 
 #ifdef	_KERNEL
-void	ktrnamei(char *);
+void	ktrnamei(const char *);
 void	ktrcsw(int, int, const char *);
 void	ktrpsig(int, sig_t, sigset_t *, int);
 void	ktrfault(vm_offset_t, int);
Index: sys/sys/mman.h
===================================================================
--- sys/sys/mman.h
+++ sys/sys/mman.h
@@ -292,6 +292,8 @@
 void	shm_drop(struct shmfd *shmfd);
 int	shm_dotruncate(struct shmfd *shmfd, off_t length);
 
+const char *	shm_name(struct file *fp);
+
 extern struct fileops shm_ops;
 #else /* !_KERNEL */
 
Index: sys/sys/pmclog.h
===================================================================
--- sys/sys/pmclog.h
+++ sys/sys/pmclog.h
@@ -306,12 +306,13 @@
 void	pmclog_process_map_out(struct pmc_owner *po, pid_t pid,
     uintfptr_t start, uintfptr_t end);
 void	pmclog_process_pmcallocate(struct pmc *_pm);
-void	pmclog_process_pmcattach(struct pmc *_pm, pid_t _pid, char *_path);
+void	pmclog_process_pmcattach(struct pmc *_pm, pid_t _pid,
+    const char *_path);
 void	pmclog_process_pmcdetach(struct pmc *_pm, pid_t _pid);
 void	pmclog_process_proccsw(struct pmc *_pm, struct pmc_process *_pp,
     pmc_value_t _v, struct thread *);
 void	pmclog_process_procexec(struct pmc_owner *_po, pmc_id_t _pmid, pid_t _pid,
-    uintfptr_t _startaddr, char *_path);
+    uintfptr_t _startaddr, const char *_path);
 void	pmclog_process_procexit(struct pmc *_pm, struct pmc_process *_pp);
 void	pmclog_process_procfork(struct pmc_owner *_po, pid_t _oldpid, pid_t _newpid);
 void	pmclog_process_sysexit(struct pmc_owner *_po, pid_t _pid);
Index: sys/sys/vnode.h
===================================================================
--- sys/sys/vnode.h
+++ sys/sys/vnode.h
@@ -631,11 +631,12 @@
 int	speedup_syncer(void);
 int	vn_vptocnp(struct vnode **vp, struct ucred *cred, char *buf,
 	    size_t *buflen);
-int	vn_getcwd(struct thread *td, char *buf, char **retbuf, size_t *buflen);
+int	vn_getcwd(struct thread *td, char *buf, const char **retbuf,
+	    size_t *buflen);
 int	vn_fullpath(struct thread *td, struct vnode *vn,
-	    char **retbuf, char **freebuf);
+	    const char **retbuf, char **freebuf);
 int	vn_fullpath_global(struct thread *td, struct vnode *vn,
-	    char **retbuf, char **freebuf);
+	    const char **retbuf, char **freebuf);
 struct vnode *
 	vn_dir_dd_ino(struct vnode *vp);
 int	vn_commname(struct vnode *vn, char *buf, u_int buflen);
Index: sys/vm/vm_object.c
===================================================================
--- sys/vm/vm_object.c
+++ sys/vm/vm_object.c
@@ -2520,7 +2520,8 @@
 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS)
 {
 	struct kinfo_vmobject *kvo;
-	char *fullpath, *freepath;
+	const char *fullpath;
+	char *freepath;
 	struct vnode *vp;
 	struct vattr va;
 	vm_object_t obj;