2 * Copyright (c) 1993 Jan-Simon Pendry
3 * Copyright (c) 1993 Sean Eric Fagan
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
8 * Jan-Simon Pendry and Sean Eric Fagan.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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
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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.
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38 * @(#)procfs_mem.c 8.5 (Berkeley) 6/15/94
40 * $FreeBSD: src/sys/miscfs/procfs/procfs_mem.c,v 1.46.2.3 2002/01/22 17:22:59 nectar Exp $
41 * $DragonFly: src/sys/vfs/procfs/procfs_mem.c,v 1.16 2007/04/29 18:25:40 dillon Exp $
45 * This is a lightly hacked and merged version
46 * of sef's pread/pwrite functions
49 #include <sys/param.h>
50 #include <sys/systm.h>
53 #include <sys/vnode.h>
54 #include <vfs/procfs/procfs.h>
56 #include <vm/vm_param.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>
65 #include <sys/ptrace.h>
67 #include <sys/thread2.h>
68 #include <sys/sysref2.h>
70 static int procfs_rwmem (struct proc *curp,
71 struct proc *p, struct uio *uio);
74 procfs_rwmem(struct proc *curp, struct proc *p, struct uio *uio)
80 vm_offset_t pageno = 0; /* page number */
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.
90 sysref_get(&vm->vm_sysref);
91 if ((p->p_flag & P_WEXIT) || sysref_isinactive(&vm->vm_sysref)) {
92 sysref_put(&vm->vm_sysref);
101 writing = uio->uio_rw == UIO_WRITE;
102 reqprot = VM_PROT_READ;
104 reqprot |= VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE;
106 kva = kmem_alloc_pageable(&kernel_map, PAGE_SIZE);
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?
114 int page_offset; /* offset into page */
118 uva = (vm_offset_t) uio->uio_offset;
121 * Get the page number of this segment.
123 pageno = trunc_page(uva);
124 page_offset = uva - pageno;
127 * How many bytes to copy
129 len = min(PAGE_SIZE - page_offset, uio->uio_resid);
132 * Fault the page on behalf of the process
134 m = vm_fault_page(map, pageno, reqprot,
135 VM_FAULT_NORMAL, &error);
143 * Cleanup tmap then create a temporary KVA mapping and
146 pmap_kenter(kva, VM_PAGE_TO_PHYS(m));
147 error = uiomove((caddr_t)(kva + page_offset), len, uio);
151 * release the page and we are done
156 } while (error == 0 && uio->uio_resid > 0);
158 kmem_free(&kernel_map, kva, PAGE_SIZE);
159 sysref_put(&vm->vm_sysref);
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.
170 procfs_domem(struct proc *curp, struct lwp *lp, struct pfsnode *pfs,
173 struct proc *p = lp->lwp_proc;
175 if (uio->uio_resid == 0)
178 /* Can't trace a process that's currently exec'ing. */
179 if ((p->p_flag & P_INEXEC) != 0)
181 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred))
184 return (procfs_rwmem(curp, p, uio));
188 * Given process (p), find the vnode from which
189 * its text segment is being executed.
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.
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.
213 procfs_findtextvp(struct proc *p)
215 return (p->p_textvp);