svn commit: r185765 - in head/sys: compat/linprocfs fs/procfs

[Konstantin Belousov]

Author: kib
Date: Mon Dec  8 12:34:52 2008
New Revision: 185765
URL: http://svn.freebsd.org/changeset/base/185765

Log:
  Change the linprocfs <pid>/maps and procfs <pid>/map handlers to use
  sbuf instead of doing uiomove. This allows for reads from non-zero
  offsets to work.
  
  Patch is forward-ported des@' one, and was adopted to current code
  by dchagin@ and me.
  
  Reviewed by:	des (linprocfs part)
  PR:	kern/101453
  MFC after:	1 week

Modified:
  head/sys/compat/linprocfs/linprocfs.c
  head/sys/fs/procfs/procfs_map.c

Modified: head/sys/compat/linprocfs/linprocfs.c
==============================================================================
--- head/sys/compat/linprocfs/linprocfs.c	Mon Dec  8 12:29:30 2008	(r185764)
+++ head/sys/compat/linprocfs/linprocfs.c	Mon Dec  8 12:34:52 2008	(r185765)
@@ -876,10 +876,12 @@ static int
 linprocfs_doprocmaps(PFS_FILL_ARGS)
 {
 	vm_map_t map = &p->p_vmspace->vm_map;
-	vm_map_entry_t entry;
+	vm_map_entry_t entry, tmp_entry;
 	vm_object_t obj, tobj, lobj;
-	vm_offset_t saved_end;
+	vm_offset_t e_start, e_end;
 	vm_ooffset_t off = 0;
+	vm_prot_t e_prot;
+	unsigned int last_timestamp;
 	char *name = "", *freename = NULL;
 	ino_t ino;
 	int ref_count, shadow_count, flags;
@@ -905,7 +907,9 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
 		freename = NULL;
 		if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
 			continue;
-		saved_end = entry->end;
+		e_prot = entry->protection;
+		e_start = entry->start;
+		e_end = entry->end;
 		obj = entry->object.vm_object;
 		for (lobj = tobj = obj; tobj; tobj = tobj->backing_object) {
 			VM_OBJECT_LOCK(tobj);
@@ -913,6 +917,8 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
 				VM_OBJECT_UNLOCK(lobj);
 			lobj = tobj;
 		}
+		last_timestamp = map->timestamp;
+		vm_map_unlock_read(map);
 		ino = 0;
 		if (lobj) {
 			off = IDX_TO_OFF(lobj->size);
@@ -950,10 +956,10 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
 		 */
 		error = sbuf_printf(sb,
 		    "%08lx-%08lx %s%s%s%s %08lx %02x:%02x %lu%s%s\n",
-		    (u_long)entry->start, (u_long)entry->end,
-		    (entry->protection & VM_PROT_READ)?"r":"-",
-		    (entry->protection & VM_PROT_WRITE)?"w":"-",
-		    (entry->protection & VM_PROT_EXECUTE)?"x":"-",
+		    (u_long)e_start, (u_long)e_end,
+		    (e_prot & VM_PROT_READ)?"r":"-",
+		    (e_prot & VM_PROT_WRITE)?"w":"-",
+		    (e_prot & VM_PROT_EXECUTE)?"x":"-",
 		    "p",
 		    (u_long)off,
 		    0,
@@ -968,6 +974,16 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
 			error = 0;
 			break;
 		}
+		vm_map_lock_read(map);
+		if (last_timestamp + 1 != map->timestamp) {
+			/*
+			 * Look again for the entry because the map was
+			 * modified while it was unlocked.  Specifically,
+			 * the entry may have been clipped, merged, or deleted.
+			 */
+			vm_map_lookup_entry(map, e_end - 1, &tmp_entry);
+			entry = tmp_entry;
+		}
 	}
 	vm_map_unlock_read(map);
 

Modified: head/sys/fs/procfs/procfs_map.c
==============================================================================
--- head/sys/fs/procfs/procfs_map.c	Mon Dec  8 12:29:30 2008	(r185764)
+++ head/sys/fs/procfs/procfs_map.c	Mon Dec  8 12:34:52 2008	(r185765)
@@ -84,9 +84,10 @@ procfs_doprocmap(PFS_FILL_ARGS)
 {
 	int error, vfslocked;
 	vm_map_t map = &p->p_vmspace->vm_map;
-	vm_map_entry_t entry;
+	vm_map_entry_t entry, tmp_entry;
 	struct vnode *vp;
 	char *fullpath, *freepath;
+	unsigned int last_timestamp;
 #ifdef COMPAT_IA32
 	int wrap32 = 0;
 #endif
@@ -113,13 +114,19 @@ procfs_doprocmap(PFS_FILL_ARGS)
 	     entry = entry->next) {
 		vm_object_t obj, tobj, lobj;
 		int ref_count, shadow_count, flags;
-		vm_offset_t addr;
+		vm_offset_t e_start, e_end, addr;
 		int resident, privateresident;
 		char *type;
+		vm_eflags_t e_eflags;
+		vm_prot_t e_prot;
 
 		if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
 			continue;
 
+		e_eflags = entry->eflags;
+		e_prot = entry->protection;
+		e_start = entry->start;
+		e_end = entry->end;
 		privateresident = 0;
 		obj = entry->object.vm_object;
 		if (obj != NULL) {
@@ -143,11 +150,13 @@ procfs_doprocmap(PFS_FILL_ARGS)
 				VM_OBJECT_UNLOCK(lobj);
 			lobj = tobj;
 		}
+		last_timestamp = map->timestamp;
+		vm_map_unlock_read(map);
 
 		freepath = NULL;
 		fullpath = "-";
 		if (lobj) {
-			switch(lobj->type) {
+			switch (lobj->type) {
 			default:
 			case OBJT_DEFAULT:
 				type = "default";
@@ -193,19 +202,19 @@ procfs_doprocmap(PFS_FILL_ARGS)
 		 */
 		error = sbuf_printf(sb,
 		    "0x%lx 0x%lx %d %d %p %s%s%s %d %d 0x%x %s %s %s %s\n",
-			(u_long)entry->start, (u_long)entry->end,
+			(u_long)e_start, (u_long)e_end,
 			resident, privateresident,
 #ifdef COMPAT_IA32
 			wrap32 ? NULL : obj,	/* Hide 64 bit value */
 #else
 			obj,
 #endif
-			(entry->protection & VM_PROT_READ)?"r":"-",
-			(entry->protection & VM_PROT_WRITE)?"w":"-",
-			(entry->protection & VM_PROT_EXECUTE)?"x":"-",
+			(e_prot & VM_PROT_READ)?"r":"-",
+			(e_prot & VM_PROT_WRITE)?"w":"-",
+			(e_prot & VM_PROT_EXECUTE)?"x":"-",
 			ref_count, shadow_count, flags,
-			(entry->eflags & MAP_ENTRY_COW)?"COW":"NCOW",
-			(entry->eflags & MAP_ENTRY_NEEDS_COPY)?"NC":"NNC",
+			(e_eflags & MAP_ENTRY_COW)?"COW":"NCOW",
+			(e_eflags & MAP_ENTRY_NEEDS_COPY)?"NC":"NNC",
 			type, fullpath);
 
 		if (freepath != NULL)
@@ -215,6 +224,16 @@ procfs_doprocmap(PFS_FILL_ARGS)
 			error = 0;
 			break;
 		}
+		vm_map_lock_read(map);
+		if (last_timestamp + 1 != map->timestamp) {
+			/*
+			 * Look again for the entry because the map was
+			 * modified while it was unlocked.  Specifically,
+			 * the entry may have been clipped, merged, or deleted.
+			 */
+			vm_map_lookup_entry(map, e_end - 1, &tmp_entry);
+			entry = tmp_entry;
+		}
 	}
 	vm_map_unlock_read(map);
 	return (error);