AMD64 - Refactor uio_resid and size_t assumptions.
[dragonfly.git] / sys / vfs / procfs / procfs_mem.c
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1/*
2 * Copyright (c) 1993 Jan-Simon Pendry
3 * Copyright (c) 1993 Sean Eric Fagan
4 * Copyright (c) 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Jan-Simon Pendry and Sean Eric Fagan.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)procfs_mem.c 8.5 (Berkeley) 6/15/94
39 *
40 * $FreeBSD: src/sys/miscfs/procfs/procfs_mem.c,v 1.46.2.3 2002/01/22 17:22:59 nectar Exp $
e3161323 41 * $DragonFly: src/sys/vfs/procfs/procfs_mem.c,v 1.16 2007/04/29 18:25:40 dillon Exp $
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42 */
43
44/*
45 * This is a lightly hacked and merged version
46 * of sef's pread/pwrite functions
47 */
48
49#include <sys/param.h>
50#include <sys/systm.h>
51#include <sys/proc.h>
75bda2d9 52#include <sys/priv.h>
984263bc 53#include <sys/vnode.h>
1f2de5d4 54#include <vfs/procfs/procfs.h>
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55#include <vm/vm.h>
56#include <vm/vm_param.h>
57#include <sys/lock.h>
58#include <vm/pmap.h>
59#include <vm/vm_extern.h>
60#include <vm/vm_map.h>
61#include <vm/vm_kern.h>
62#include <vm/vm_object.h>
63#include <vm/vm_page.h>
64#include <sys/user.h>
65#include <sys/ptrace.h>
66
654a39f0 67#include <sys/thread2.h>
e3161323 68#include <sys/sysref2.h>
654a39f0 69
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70static int procfs_rwmem (struct proc *curp,
71 struct proc *p, struct uio *uio);
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72
73static int
ac424f9b 74procfs_rwmem(struct proc *curp, struct proc *p, struct uio *uio)
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75{
76 int error;
77 int writing;
78 struct vmspace *vm;
79 vm_map_t map;
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80 vm_offset_t pageno = 0; /* page number */
81 vm_prot_t reqprot;
82 vm_offset_t kva;
83
84 /*
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85 * if the vmspace is in the midst of being allocated or deallocated,
86 * or the process is exiting, don't try to grab anything. The
87 * page table usage in that process may be messed up.
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88 */
89 vm = p->p_vmspace;
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90 sysref_get(&vm->vm_sysref);
91 if ((p->p_flag & P_WEXIT) || sysref_isinactive(&vm->vm_sysref)) {
92 sysref_put(&vm->vm_sysref);
984263bc 93 return EFAULT;
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94 }
95
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96 /*
97 * The map we want...
98 */
99 map = &vm->vm_map;
100
101 writing = uio->uio_rw == UIO_WRITE;
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102 reqprot = VM_PROT_READ;
103 if (writing)
104 reqprot |= VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE;
984263bc 105
e4846942 106 kva = kmem_alloc_pageable(&kernel_map, PAGE_SIZE);
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107
108 /*
109 * Only map in one page at a time. We don't have to, but it
110 * makes things easier. This way is trivial - right?
111 */
112 do {
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113 vm_offset_t uva;
114 int page_offset; /* offset into page */
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115 u_int len;
116 vm_page_t m;
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117
118 uva = (vm_offset_t) uio->uio_offset;
119
120 /*
121 * Get the page number of this segment.
122 */
123 pageno = trunc_page(uva);
124 page_offset = uva - pageno;
125
126 /*
127 * How many bytes to copy
128 */
e54488bb 129 len = szmin(PAGE_SIZE - page_offset, uio->uio_resid);
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130
131 /*
132 * Fault the page on behalf of the process
133 */
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134 m = vm_fault_page(map, pageno, reqprot,
135 VM_FAULT_NORMAL, &error);
984263bc 136 if (error) {
4e158347 137 KKASSERT(m == NULL);
06ecca5a 138 error = EFAULT;
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139 break;
140 }
141
142 /*
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143 * Cleanup tmap then create a temporary KVA mapping and
144 * do the I/O.
984263bc 145 */
984263bc 146 pmap_kenter(kva, VM_PAGE_TO_PHYS(m));
984263bc 147 error = uiomove((caddr_t)(kva + page_offset), len, uio);
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148 pmap_kremove(kva);
149
150 /*
06ecca5a 151 * release the page and we are done
984263bc 152 */
654a39f0 153 crit_enter();
b6f5e86b 154 vm_page_unhold(m);
654a39f0 155 crit_exit();
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156 } while (error == 0 && uio->uio_resid > 0);
157
e4846942 158 kmem_free(&kernel_map, kva, PAGE_SIZE);
e3161323 159 sysref_put(&vm->vm_sysref);
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160 return (error);
161}
162
163/*
164 * Copy data in and out of the target process.
165 * We do this by mapping the process's page into
166 * the kernel and then doing a uiomove direct
167 * from the kernel address space.
168 */
169int
c7e98b2f 170procfs_domem(struct proc *curp, struct lwp *lp, struct pfsnode *pfs,
ac424f9b 171 struct uio *uio)
984263bc 172{
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173 struct proc *p = lp->lwp_proc;
174
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175 if (uio->uio_resid == 0)
176 return (0);
177
178 /* Can't trace a process that's currently exec'ing. */
179 if ((p->p_flag & P_INEXEC) != 0)
180 return EAGAIN;
41c20dac 181 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred))
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182 return EPERM;
183
184 return (procfs_rwmem(curp, p, uio));
185}
186
187/*
188 * Given process (p), find the vnode from which
189 * its text segment is being executed.
190 *
191 * It would be nice to grab this information from
192 * the VM system, however, there is no sure-fire
193 * way of doing that. Instead, fork(), exec() and
194 * wait() all maintain the p_textvp field in the
195 * process proc structure which contains a held
196 * reference to the exec'ed vnode.
197 *
198 * XXX - Currently, this is not not used, as the
199 * /proc/pid/file object exposes an information leak
200 * that shouldn't happen. Using a mount option would
201 * make it configurable on a per-system (or, at least,
202 * per-mount) basis; however, that's not really best.
203 * The best way to do it, I think, would be as an
204 * ioctl; this would restrict it to the uid running
205 * program, or root, which seems a reasonable compromise.
206 * However, the number of applications for this is
207 * minimal, if it can't be seen in the filesytem space,
208 * and doint it as an ioctl makes it somewhat less
209 * useful due to the, well, inelegance.
210 *
211 */
212struct vnode *
ac424f9b 213procfs_findtextvp(struct proc *p)
984263bc 214{
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215 return (p->p_textvp);
216}