From 4c2d301f6abfa3af6572a66d6c780f0580285c81 Mon Sep 17 00:00:00 2001
From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Wed, 27 Mar 2019 10:08:25 -0700
Subject: [PATCH] world - Fix fstat and gcore

* fstat needs to iterate vm_map_entry's
  via the RB tree, but it isn't entirely trivial because we
  have to kread().

* gcore needs to steal a different field for its iterator
  when building a map from procfs.

* Fixes buildworld.

Reported-by: zrj
---
 usr.bin/fstat/fstat.c   | 89 ++++++++++++++++++++++++++++++++++-------
 usr.bin/gcore/elfcore.c |  6 +--
 2 files changed, 77 insertions(+), 18 deletions(-)

diff --git a/usr.bin/fstat/fstat.c b/usr.bin/fstat/fstat.c
index 6bc6637d0b..46f0164792 100644
--- a/usr.bin/fstat/fstat.c
+++ b/usr.bin/fstat/fstat.c
@@ -94,6 +94,7 @@
 DEVS *devs;
 
 static void make_printable(char *buf, int len);
+static int kreadent(const void *kaddr, vm_map_entry_t copy);
 
 #ifdef notdef
 struct nlist nl[] = {
@@ -113,6 +114,11 @@ int	wflg_cmd = 10;
 int	pid_width = 5;
 int	ino_width = 6;
 
+const char *Uname;
+char	*Comm;
+int	Pid;
+
+
 struct fdnode *ofiles; 	/* buffer of pointers to file structures */
 int maxfiles;
 
@@ -267,10 +273,6 @@ main(int argc, char **argv)
 	exit(0);
 }
 
-const char *Uname;
-char	*Comm;
-int	Pid;
-
 #define PREFIX(i) \
 	printf("%-8.8s %-*s %*d", Uname, wflg_cmd, Comm, pid_width, Pid); \
 	switch(i) { \
@@ -387,13 +389,67 @@ dofiles(struct kinfo_proc *kp, struct proc *p)
 	}
 }
 
+static
+vm_map_entry_t
+kinfo_vm_map_entry_first(vm_map_t map, vm_map_entry_t copy)
+{
+	vm_map_entry_t ken;
+
+	ken = map->rb_root.rbh_root;
+	if (ken == NULL)
+		return NULL;
+	if (!kreadent(ken, copy))
+		return NULL;
+	while (copy->rb_entry.rbe_left) {
+		ken = copy->rb_entry.rbe_left;
+		if (!kreadent(ken, copy))
+			return NULL;
+	}
+	return ken;
+}
+
+static
+vm_map_entry_t
+kinfo_vm_map_entry_next(vm_map_entry_t ken, vm_map_entry_t copy)
+{
+	vm_map_entry_t ken2;
+
+	if (copy->rb_entry.rbe_right) {
+		ken = copy->rb_entry.rbe_right;
+		if (!kreadent(ken, copy))
+			return NULL;
+		while (copy->rb_entry.rbe_left) {
+			ken = copy->rb_entry.rbe_left;
+			if (!kreadent(ken, copy))
+				return NULL;
+		}
+	} else {
+		if ((ken2 = copy->rb_entry.rbe_parent) == NULL)
+			return NULL;
+		if (!kreadent(ken2, copy))
+			return NULL;
+		if (ken == copy->rb_entry.rbe_left) {
+			ken = ken2;
+		} else {
+			while (ken == copy->rb_entry.rbe_right) {
+				ken = ken2;
+				ken2 = copy->rb_entry.rbe_parent;
+				if (!kreadent(ken2, copy))
+					return NULL;
+			}
+			ken = ken2;
+		}
+	}
+	return ken;
+}
+
 static void
 dommap(struct proc *p)
 {
 	struct vmspace vmspace;
 	vm_map_t map;
 	struct vm_map_entry entry;
-	vm_map_entry_t entryp;
+	vm_map_entry_t ken;
 	struct vm_object object;
 	vm_object_t objp;
 	int prot, fflags;
@@ -405,16 +461,9 @@ dommap(struct proc *p)
 	}
 
 	map = &vmspace.vm_map;
-
-	for (entryp = map->header.next; entryp != &p->p_vmspace->vm_map.header;
-	    entryp = entry.next) {
-		if (!kread(entryp, &entry, sizeof(entry))) {
-			dprintf(stderr,
-			    "can't read vm_map_entry at %p for pid %d\n",
-			    (void *)entryp, Pid);
-			return;
-		}
-
+	for (ken = kinfo_vm_map_entry_first(map, &entry);
+	     ken;
+	     ken = kinfo_vm_map_entry_next(ken, &entry)) {
 		if (entry.maptype == VM_MAPTYPE_SUBMAP)
 			continue;
 
@@ -1016,3 +1065,13 @@ kread(const void *kaddr, void *uaddr, size_t nbytes)
 	return(0);
 }
 
+static
+int
+kreadent(const void *kaddr, vm_map_entry_t copy)
+{
+	if (kread(kaddr, copy, sizeof(*copy)))
+		return 1;
+	dprintf(stderr, "can't read vm_map_entry at %p for pid %d\n",
+		kaddr, Pid);
+	return 0;
+}
diff --git a/usr.bin/gcore/elfcore.c b/usr.bin/gcore/elfcore.c
index 018cd81b0f..59f30facb5 100644
--- a/usr.bin/gcore/elfcore.c
+++ b/usr.bin/gcore/elfcore.c
@@ -213,7 +213,7 @@ each_writable_segment(vm_map_entry_t map, segment_callback func, void *closure)
 {
 	vm_map_entry_t entry;
 
-	for (entry = map;  entry != NULL;  entry = entry->next)
+	for (entry = map; entry; entry = entry->rb_entry.rbe_parent)
 		(*func)(entry, closure);
 }
 
@@ -359,7 +359,7 @@ static void
 freemap(vm_map_entry_t map)
 {
 	while (map != NULL) {
-		vm_map_entry_t next = map->next;
+		vm_map_entry_t next = map->rb_entry.rbe_parent;
 		free(map);
 		map = next;
 	}
@@ -531,7 +531,7 @@ readmap(pid_t pid)
 		    ent->protection |= VM_PROT_EXECUTE;
 
 		*linkp = ent;
-		linkp = &ent->next;
+		linkp = &ent->rb_entry.rbe_parent;
 	}
 	free(mapbuf);
 	return map;
-- 
2.41.0