+/*
+ * Copyright (c) 1993 The Regents of the University of California.
+ * Copyright (c) 1993 Jan-Simon Pendry
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Jan-Simon Pendry.
+ *
+ * %sccs.include.redist.c%
+ *
+ * @(#)procfs_mem.c 8.1 (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 */
projects / unix-history / commitdiff