[unix-history] / usr / src / sys / miscfs / procfs / procfs_mem.c

/*
 * Copyright (c) 1993 The Regents of the University of California.
 * Copyright (c) 1993 Jan-Simon Pendry
 * Copyright (c) 1993 Sean Eric Fagan
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jan-Simon Pendry and Sean Eric Fagan.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)procfs_mem.c	8.3 (Berkeley) %G%
 *
 * From:
 *	$Id: procfs_mem.c,v 3.2 1993/12/15 09:40:17 jsp Exp $
 */

/*
 * This is a lightly hacked and merged version
 * of sef's pread/pwrite functions
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <miscfs/procfs/procfs.h>
#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>

static int
procfs_rwmem(p, uio)
	struct proc *p;
	struct uio *uio;
{
	int error;
	int writing;

	writing = uio->uio_rw == UIO_WRITE;

	/*
	 * Only map in one page at a time.  We don't have to, but it
	 * makes things easier.  This way is trivial - right?
	 */
	do {
		vm_map_t map, tmap;
		vm_object_t object;
		vm_offset_t kva;
		vm_offset_t uva;
		int page_offset;		/* offset into page */
		vm_offset_t pageno;		/* page number */
		vm_map_entry_t out_entry;
		vm_prot_t out_prot;
		vm_page_t m;
		boolean_t wired, single_use;
		vm_offset_t off;
		u_int len;
		int fix_prot;

		uva = (vm_offset_t) uio->uio_offset;
		if (uva > VM_MAXUSER_ADDRESS) {
			error = 0;
			break;
		}

		/*
		 * Get the page number of this segment.
		 */
		pageno = trunc_page(uva);
		page_offset = uva - pageno;

		/*
		 * How many bytes to copy
		 */
		len = min(PAGE_SIZE - page_offset, uio->uio_resid);

		/*
		 * The map we want...
		 */
		map = &p->p_vmspace->vm_map;
  
		/*
		 * Check the permissions for the area we're interested
		 * in.
		 */
		fix_prot = 0;
		if (writing)
			fix_prot = !vm_map_check_protection(map, pageno,
					pageno + PAGE_SIZE, VM_PROT_WRITE);

		if (fix_prot) {
			/*
			 * If the page is not writable, we make it so.
			 * XXX It is possible that a page may *not* be
			 * read/executable, if a process changes that!
			 * We will assume, for now, that a page is either
			 * VM_PROT_ALL, or VM_PROT_READ|VM_PROT_EXECUTE.
			 */
			error = vm_map_protect(map, pageno,
					pageno + PAGE_SIZE, VM_PROT_ALL, 0);
			if (error)
				break;
		}

		/*
		 * Now we need to get the page.  out_entry, out_prot, wired,
		 * and single_use aren't used.  One would think the vm code
		 * would be a *bit* nicer...  We use tmap because
		 * vm_map_lookup() can change the map argument.
		 */
		tmap = map;
		error = vm_map_lookup(&tmap, pageno,
				      writing ? VM_PROT_WRITE : VM_PROT_READ,
				      &out_entry, &object, &off, &out_prot,
				      &wired, &single_use);
		/*
		 * We're done with tmap now.
		 */
		if (!error)
			vm_map_lookup_done(tmap, out_entry);
  
		/*
		 * Fault the page in...
		 */
		if (!error && writing && object->shadow) {
			m = vm_page_lookup(object, off);
			if (m == 0 || (m->flags & PG_COPYONWRITE))
				error = vm_fault(map, pageno,
							VM_PROT_WRITE, FALSE);
		}

		/* Find space in kernel_map for the page we're interested in */
		if (!error)
			error = vm_map_find(kernel_map, object, off, &kva,
					PAGE_SIZE, 1);

		if (!error) {
			/*
			 * Neither vm_map_lookup() nor vm_map_find() appear
			 * to add a reference count to the object, so we do
			 * that here and now.
			 */
			vm_object_reference(object);

			/*
			 * Mark the page we just found as pageable.
			 */
			error = vm_map_pageable(kernel_map, kva,
				kva + PAGE_SIZE, 0);

			/*
			 * Now do the i/o move.
			 */
			if (!error)
				error = uiomove(kva + page_offset, len, uio);

			vm_map_remove(kernel_map, kva, kva + PAGE_SIZE);
		}
		if (fix_prot)
			vm_map_protect(map, pageno, pageno + PAGE_SIZE,
					VM_PROT_READ|VM_PROT_EXECUTE, 0);
	} while (error == 0 && uio->uio_resid > 0);

	return (error);
}

/*
 * Copy data in and out of the target process.
 * We do this by mapping the process's page into
 * the kernel and then doing a uiomove direct
 * from the kernel address space.
 */
int
procfs_domem(curp, p, pfs, uio)
	struct proc *curp;
	struct proc *p;
	struct pfsnode *pfs;
	struct uio *uio;
{
	int error;

	if (uio->uio_resid == 0)
		return (0);

	error = procfs_rwmem(p, uio);

	return (error);
}

/*
 * Given process (p), find the vnode from which
 * it's text segment is being executed.
 *
 * It would be nice to grab this information from
 * the VM system, however, there is no sure-fire
 * way of doing that.  Instead, fork(), exec() and
 * wait() all maintain the p_textvp field in the
 * process proc structure which contains a held
 * reference to the exec'ed vnode.
 */
struct vnode *
procfs_findtextvp(p)
	struct proc *p;
{
	return (p->p_textvp);
}


#ifdef probably_never
/*
 * Given process (p), find the vnode from which
 * it's text segment is being mapped.
 *
 * (This is here, rather than in procfs_subr in order
 * to keep all the VM related code in one place.)
 */
struct vnode *
procfs_findtextvp(p)
	struct proc *p;
{
	int error;
	vm_object_t object;
	vm_offset_t pageno;		/* page number */

	/* find a vnode pager for the user address space */

	for (pageno = VM_MIN_ADDRESS;
			pageno < VM_MAXUSER_ADDRESS;
			pageno += PAGE_SIZE) {
		vm_map_t map;
		vm_map_entry_t out_entry;
		vm_prot_t out_prot;
		boolean_t wired, single_use;
		vm_offset_t off;

		map = &p->p_vmspace->vm_map;
		error = vm_map_lookup(&map, pageno,
			      VM_PROT_READ,
			      &out_entry, &object, &off, &out_prot,
			      &wired, &single_use);

		if (!error) {
			vm_pager_t pager;

			printf("procfs: found vm object\n");
			vm_map_lookup_done(map, out_entry);
			printf("procfs: vm object = %x\n", object);

			/*
			 * At this point, assuming no errors, object
			 * is the VM object mapping UVA (pageno).
			 * Ensure it has a vnode pager, then grab
			 * the vnode from that pager's handle.
			 */

			pager = object->pager;
			printf("procfs: pager = %x\n", pager);
			if (pager)
				printf("procfs: found pager, type = %d\n", pager->pg_type);
			if (pager && pager->pg_type == PG_VNODE) {
				struct vnode *vp;

				vp = (struct vnode *) pager->pg_handle;
				printf("procfs: vp = 0x%x\n", vp);
				return (vp);
			}
		}
	}

	printf("procfs: text object not found\n");
	return (0);
}
#endif /* probably_never */
Commit	Line	Data
66375577 JSP	1	/*
	2	* Copyright (c) 1993 The Regents of the University of California.
	3	* Copyright (c) 1993 Jan-Simon Pendry
e14d91e9	4	* Copyright (c) 1993 Sean Eric Fagan
66375577 JSP	5	* All rights reserved.
	6	*
	7	* This code is derived from software contributed to Berkeley by
ad7740d9	8	* Jan-Simon Pendry and Sean Eric Fagan.
66375577 JSP	9	*
	10	* %sccs.include.redist.c%
	11	*
e14d91e9	12	* @(#)procfs_mem.c 8.3 (Berkeley) %G%
66375577 JSP	13	*
	14	* From:
	15	* $Id: procfs_mem.c,v 3.2 1993/12/15 09:40:17 jsp Exp $
	16	*/
	17
	18	/*
	19	* This is a lightly hacked and merged version
	20	* of sef's pread/pwrite functions
	21	*/
	22
	23	#include <sys/param.h>
	24	#include <sys/systm.h>
	25	#include <sys/time.h>
	26	#include <sys/kernel.h>
	27	#include <sys/proc.h>
	28	#include <sys/vnode.h>
	29	#include <miscfs/procfs/procfs.h>
	30	#include <vm/vm.h>
	31	#include <vm/vm_kern.h>
	32	#include <vm/vm_page.h>
	33
	34	static int
	35	procfs_rwmem(p, uio)
	36	struct proc *p;
	37	struct uio *uio;
	38	{
	39	int error;
	40	int writing;
	41
	42	writing = uio->uio_rw == UIO_WRITE;
	43
	44	/*
	45	* Only map in one page at a time. We don't have to, but it
	46	* makes things easier. This way is trivial - right?
	47	*/
	48	do {
	49	vm_map_t map, tmap;
	50	vm_object_t object;
	51	vm_offset_t kva;
	52	vm_offset_t uva;
	53	int page_offset; /* offset into page */
	54	vm_offset_t pageno; /* page number */
	55	vm_map_entry_t out_entry;
	56	vm_prot_t out_prot;
	57	vm_page_t m;
	58	boolean_t wired, single_use;
	59	vm_offset_t off;
	60	u_int len;
	61	int fix_prot;
	62
	63	uva = (vm_offset_t) uio->uio_offset;
	64	if (uva > VM_MAXUSER_ADDRESS) {
	65	error = 0;
	66	break;
	67	}
	68
	69	/*
	70	* Get the page number of this segment.
	71	*/
	72	pageno = trunc_page(uva);
	73	page_offset = uva - pageno;
	74
	75	/*
	76	* How many bytes to copy
77	*/
78	len = min(PAGE_SIZE - page_offset, uio->uio_resid);
79
80	/*
81	* The map we want...
82	*/
83	map = &p->p_vmspace->vm_map;
84
85	/*
86	* Check the permissions for the area we're interested
87	* in.
88	*/
89	fix_prot = 0;
90	if (writing)
91	fix_prot = !vm_map_check_protection(map, pageno,
92	pageno + PAGE_SIZE, VM_PROT_WRITE);
93
94	if (fix_prot) {
95	/*
96	* If the page is not writable, we make it so.
97	* XXX It is possible that a page may not be
98	* read/executable, if a process changes that!
99	* We will assume, for now, that a page is either
100	* VM_PROT_ALL, or VM_PROT_READ\|VM_PROT_EXECUTE.
101	*/
102	error = vm_map_protect(map, pageno,
103	pageno + PAGE_SIZE, VM_PROT_ALL, 0);
104	if (error)
105	break;
106	}
107
108	/*
109	* Now we need to get the page. out_entry, out_prot, wired,
110	* and single_use aren't used. One would think the vm code
111	* would be a bit nicer... We use tmap because
112	* vm_map_lookup() can change the map argument.
113	*/
114	tmap = map;
115	error = vm_map_lookup(&tmap, pageno,
116	writing ? VM_PROT_WRITE : VM_PROT_READ,
117	&out_entry, &object, &off, &out_prot,
118	&wired, &single_use);
119	/*
120	* We're done with tmap now.
121	*/
122	if (!error)
123	vm_map_lookup_done(tmap, out_entry);
124
125	/*
126	* Fault the page in...
127	*/
128	if (!error && writing && object->shadow) {
129	m = vm_page_lookup(object, off);
130	if (m == 0 \|\| (m->flags & PG_COPYONWRITE))
131	error = vm_fault(map, pageno,
132	VM_PROT_WRITE, FALSE);
133	}
134
135	/* Find space in kernel_map for the page we're interested in */
136	if (!error)
137	error = vm_map_find(kernel_map, object, off, &kva,
138	PAGE_SIZE, 1);
139
140	if (!error) {
141	/*
142	* Neither vm_map_lookup() nor vm_map_find() appear
143	* to add a reference count to the object, so we do
144	* that here and now.
145	*/
146	vm_object_reference(object);
147
148	/*
149	* Mark the page we just found as pageable.
150	*/
151	error = vm_map_pageable(kernel_map, kva,
152	kva + PAGE_SIZE, 0);
153
154	/*
155	* Now do the i/o move.
156	*/
157	if (!error)
158	error = uiomove(kva + page_offset, len, uio);
159
160	vm_map_remove(kernel_map, kva, kva + PAGE_SIZE);
161	}
162	if (fix_prot)
163	vm_map_protect(map, pageno, pageno + PAGE_SIZE,
164	VM_PROT_READ\|VM_PROT_EXECUTE, 0);
165	} while (error == 0 && uio->uio_resid > 0);
166
167	return (error);
168	}
169
170	/*
171	* Copy data in and out of the target process.
172	* We do this by mapping the process's page into
173	* the kernel and then doing a uiomove direct
174	* from the kernel address space.
175	*/
176	int
177	procfs_domem(curp, p, pfs, uio)
178	struct proc *curp;
179	struct proc *p;
180	struct pfsnode *pfs;
181	struct uio *uio;
182	{
183	int error;
184
185	if (uio->uio_resid == 0)
186	return (0);
187
188	error = procfs_rwmem(p, uio);
189
190	return (error);
191	}
192
193	/*
194	* Given process (p), find the vnode from which
195	* it's text segment is being executed.
196	*
197	* It would be nice to grab this information from
198	* the VM system, however, there is no sure-fire
199	* way of doing that. Instead, fork(), exec() and
200	* wait() all maintain the p_textvp field in the
201	* process proc structure which contains a held
202	* reference to the exec'ed vnode.
203	*/
204	struct vnode *
205	procfs_findtextvp(p)
206	struct proc *p;
207	{
208	return (p->p_textvp);
209	}
210
211
212	#ifdef probably_never
213	/*
214	* Given process (p), find the vnode from which
215	* it's text segment is being mapped.
216	*
217	* (This is here, rather than in procfs_subr in order
218	* to keep all the VM related code in one place.)
219	*/
220	struct vnode *
221	procfs_findtextvp(p)
222	struct proc *p;
223	{
224	int error;
225	vm_object_t object;
226	vm_offset_t pageno; /* page number */
227
228	/* find a vnode pager for the user address space */
229
230	for (pageno = VM_MIN_ADDRESS;
231	pageno < VM_MAXUSER_ADDRESS;
232	pageno += PAGE_SIZE) {
233	vm_map_t map;
234	vm_map_entry_t out_entry;
235	vm_prot_t out_prot;
236	boolean_t wired, single_use;
237	vm_offset_t off;
238
239	map = &p->p_vmspace->vm_map;
240	error = vm_map_lookup(&map, pageno,
241	VM_PROT_READ,
242	&out_entry, &object, &off, &out_prot,
243	&wired, &single_use);
244
245	if (!error) {
246	vm_pager_t pager;
247
248	printf("procfs: found vm object\n");
249	vm_map_lookup_done(map, out_entry);
250	printf("procfs: vm object = %x\n", object);
251
252	/*
253	* At this point, assuming no errors, object
254	* is the VM object mapping UVA (pageno).
255	* Ensure it has a vnode pager, then grab
256	* the vnode from that pager's handle.
257	*/
258
259	pager = object->pager;
260	printf("procfs: pager = %x\n", pager);
261	if (pager)
262	printf("procfs: found pager, type = %d\n", pager->pg_type);
263	if (pager && pager->pg_type == PG_VNODE) {
264	struct vnode *vp;
265
266	vp = (struct vnode *) pager->pg_handle;
267	printf("procfs: vp = 0x%x\n", vp);
268	return (vp);
269	}
270	}
271	}
272
273	printf("procfs: text object not found\n");
274	return (0);
275	}
276	#endif /* probably_never */