xref: /dragonfly/sys/vfs/procfs/procfs_map.c (revision ad9f8794)
1 /*
2  * Copyright (c) 1993 Jan-Simon Pendry
3  * Copyright (c) 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * Jan-Simon Pendry.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)procfs_status.c	8.3 (Berkeley) 2/17/94
34  *
35  * $FreeBSD: src/sys/miscfs/procfs/procfs_map.c,v 1.24.2.1 2001/08/04 13:12:24 rwatson Exp $
36  * $DragonFly: src/sys/vfs/procfs/procfs_map.c,v 1.7 2007/02/19 01:14:24 corecode Exp $
37  */
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/proc.h>
42 #include <sys/vnode.h>
43 #include <vfs/procfs/procfs.h>
44 
45 #include <vm/vm.h>
46 #include <sys/lock.h>
47 #include <vm/pmap.h>
48 #include <vm/vm_map.h>
49 #include <vm/vm_page.h>
50 #include <vm/vm_object.h>
51 
52 
53 #define MEBUFFERSIZE 256
54 
55 /*
56  * The map entries can *almost* be read with programs like cat.  However,
57  * large maps need special programs to read.  It is not easy to implement
58  * a program that can sense the required size of the buffer, and then
59  * subsequently do a read with the appropriate size.  This operation cannot
60  * be atomic.  The best that we can do is to allow the program to do a read
61  * with an arbitrarily large buffer, and return as much as we can.  We can
62  * return an error code if the buffer is too small (EFBIG), then the program
63  * can try a bigger buffer.
64  */
65 int
66 procfs_domap(struct proc *curp, struct lwp *lp, struct pfsnode *pfs,
67 	     struct uio *uio)
68 {
69 	struct proc *p = lp->lwp_proc;
70 	int len;
71 	struct vnode *vp;
72 	char *fullpath, *freepath;
73 	int error;
74 	vm_map_t map = &p->p_vmspace->vm_map;
75 	pmap_t pmap = vmspace_pmap(p->p_vmspace);
76 	vm_map_entry_t entry;
77 	char mebuffer[MEBUFFERSIZE];
78 
79 	if (uio->uio_rw != UIO_READ)
80 		return (EOPNOTSUPP);
81 
82 	if (uio->uio_offset != 0)
83 		return (0);
84 
85 	error = 0;
86 	vm_map_lock_read(map);
87 	for (entry = map->header.next;
88 		((uio->uio_resid > 0) && (entry != &map->header));
89 		entry = entry->next) {
90 		vm_object_t obj, tobj, lobj;
91 		int ref_count, shadow_count, flags;
92 		vm_offset_t addr;
93 		vm_offset_t ostart;
94 		int resident, privateresident;
95 		char *type;
96 
97 		if (entry->maptype != VM_MAPTYPE_NORMAL &&
98 		    entry->maptype != VM_MAPTYPE_VPAGETABLE) {
99 			continue;
100 		}
101 
102 		obj = entry->object.vm_object;
103 		if (obj && (obj->shadow_count == 1))
104 			privateresident = obj->resident_page_count;
105 		else
106 			privateresident = 0;
107 
108 		/*
109 		 * Use map->hint as a poor man's ripout detector.
110 		 */
111 		map->hint = entry;
112 		ostart = entry->start;
113 
114 		/*
115 		 * Count resident pages (XXX can be horrible on 64-bit)
116 		 */
117 		resident = 0;
118 		addr = entry->start;
119 		while (addr < entry->end) {
120 			if (pmap_extract( pmap, addr))
121 				resident++;
122 			addr += PAGE_SIZE;
123 		}
124 
125 		for( lobj = tobj = obj; tobj; tobj = tobj->backing_object)
126 			lobj = tobj;
127 
128 		freepath = NULL;
129 		fullpath = "-";
130 		if (lobj) {
131 			switch(lobj->type) {
132 			default:
133 			case OBJT_DEFAULT:
134 				type = "default";
135 				vp = NULL;
136 				break;
137 			case OBJT_VNODE:
138 				type = "vnode";
139 				vp = lobj->handle;
140 				vref(vp);
141 				break;
142 			case OBJT_SWAP:
143 				type = "swap";
144 				vp = NULL;
145 				break;
146 			case OBJT_DEVICE:
147 				type = "device";
148 				vp = NULL;
149 				break;
150 			}
151 
152 			flags = obj->flags;
153 			ref_count = obj->ref_count;
154 			shadow_count = obj->shadow_count;
155 			if (vp != NULL) {
156 				vn_fullpath(p, vp, &fullpath, &freepath, 1);
157 				vrele(vp);
158 			}
159 		} else {
160 			type = "none";
161 			flags = 0;
162 			ref_count = 0;
163 			shadow_count = 0;
164 		}
165 
166 		/*
167 		 * format:
168 		 *  start, end, res, priv res, cow, access, type, (fullpath).
169 		 */
170 		ksnprintf(mebuffer, sizeof(mebuffer),
171 		    "0x%lx 0x%lx %d %d %p %s%s%s %d %d 0x%x %s %s %s %s\n",
172 			(u_long)entry->start, (u_long)entry->end,
173 			resident, privateresident, obj,
174 			(entry->protection & VM_PROT_READ)?"r":"-",
175 			(entry->protection & VM_PROT_WRITE)?"w":"-",
176 			(entry->protection & VM_PROT_EXECUTE)?"x":"-",
177 			ref_count, shadow_count, flags,
178 			(entry->eflags & MAP_ENTRY_COW)?"COW":"NCOW",
179 			(entry->eflags & MAP_ENTRY_NEEDS_COPY)?"NC":"NNC",
180 			type, fullpath);
181 
182 		if (freepath != NULL) {
183 			kfree(freepath, M_TEMP);
184 			freepath = NULL;
185 		}
186 
187 		len = strlen(mebuffer);
188 		if (len > uio->uio_resid) {
189 			error = EFBIG;
190 			break;
191 		}
192 
193 		/*
194 		 * We cannot safely hold the map locked while accessing
195 		 * userspace as a VM fault might recurse the locked map.
196 		 */
197 		vm_map_unlock_read(map);
198 		error = uiomove(mebuffer, len, uio);
199 		vm_map_lock_read(map);
200 		if (error)
201 			break;
202 
203 		/*
204 		 * We use map->hint as a poor man's ripout detector.  If
205 		 * it does not match the entry we set it to prior to
206 		 * unlocking the map the entry MIGHT now be stale.  In
207 		 * this case we do an expensive lookup to find our place
208 		 * in the iteration again.
209 		 */
210 		if (map->hint != entry) {
211 			vm_map_entry_t reentry;
212 
213 			vm_map_lookup_entry(map, ostart, &reentry);
214 			entry = reentry;
215 		}
216 	}
217 	vm_map_unlock_read(map);
218 
219 	return error;
220 }
221 
222 int
223 procfs_validmap(struct lwp *lp)
224 {
225 	return ((lp->lwp_proc->p_flag & P_SYSTEM) == 0);
226 }
227