/* * Copyright (c) 1993 Jan-Simon Pendry * Copyright (c) 1993 Sean Eric Fagan * Copyright (c) 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Jan-Simon Pendry and Sean Eric Fagan. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)procfs_mem.c 8.5 (Berkeley) 6/15/94 * * $FreeBSD: src/sys/miscfs/procfs/procfs_mem.c,v 1.46.2.3 2002/01/22 17:22:59 nectar 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/uio.h> #include <sys/proc.h> #include <sys/caps.h> #include <sys/vnode.h> #include <vfs/procfs/procfs.h> #include <vm/vm.h> #include <vm/vm_param.h> #include <sys/lock.h> #include <vm/pmap.h> #include <vm/vm_extern.h> #include <vm/vm_map.h> #include <vm/vm_kern.h> #include <vm/vm_object.h> #include <vm/vm_page.h> #include <sys/ptrace.h> static int procfs_rwmem (struct proc *curp, struct proc *p, struct uio *uio); /* * p->p_token is held on entry. */ static int procfs_rwmem(struct proc *curp, struct proc *p, struct uio *uio) { int error; int writing; struct vmspace *vm; vm_map_t map; vm_offset_t pageno = 0; /* page number */ vm_prot_t reqprot; vm_offset_t kva; /* * if the vmspace is in the midst of being allocated or deallocated, * or the process is exiting, don't try to grab anything. The * page table usage in that process may be messed up. */ vm = p->p_vmspace; if (p->p_stat == SIDL || p->p_stat == SZOMB) return EFAULT; if ((p->p_flags & (P_WEXIT | P_INEXEC)) || vmspace_getrefs(vm) < 0) return EFAULT; /* * The map we want... */ vmspace_hold(vm); map = &vm->vm_map; writing = (uio->uio_rw == UIO_WRITE); reqprot = VM_PROT_READ; if (writing) reqprot |= VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE; kva = kmem_alloc_pageable(kernel_map, PAGE_SIZE, VM_SUBSYS_PROC); /* * 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_offset_t uva; vm_offset_t page_offset; /* offset into page */ size_t len; vm_page_t m; int busy; uva = (vm_offset_t) uio->uio_offset; /* * Get the page number of this segment. */ pageno = trunc_page(uva); page_offset = uva - pageno; /* * How many bytes to copy */ len = szmin(PAGE_SIZE - page_offset, uio->uio_resid); /* * Fault the page on behalf of the process * * XXX busied page on write fault can deadlock against our * uiomove. */ m = vm_fault_page(map, pageno, reqprot, VM_FAULT_NORMAL, &error, &busy); if (error) { KKASSERT(m == NULL); error = EFAULT; break; } /* * Cleanup pmap then create a temporary KVA mapping and * do the I/O. We can switch between cpus so don't bother * synchronizing across all cores. */ pmap_kenter_quick(kva, VM_PAGE_TO_PHYS(m)); error = uiomove((caddr_t)(kva + page_offset), len, uio); pmap_kremove_quick(kva); /* * Release the page and we are done */ if (busy) vm_page_wakeup(m); else vm_page_unhold(m); } while (error == 0 && uio->uio_resid > 0); vmspace_drop(vm); kmem_free(kernel_map, kva, PAGE_SIZE); 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. * * lp->lwp_proc->p_token is held on entry. */ int procfs_domem(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, struct uio *uio) { struct proc *p = lp->lwp_proc; int error; if (uio->uio_resid == 0) return (0); if ((p->p_flags & P_INEXEC) != 0) { /* * Can't trace a process that's currently exec'ing. */ error = EAGAIN; } else if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) { /* * Can't trace processes outside our jail */ error = EPERM; } else { error = procfs_rwmem(curp, p, uio); } return(error); } /* * Given process (p), find the vnode from which * its 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. * * XXX - Currently, this is not not used, as the * /proc/pid/file object exposes an information leak * that shouldn't happen. Using a mount option would * make it configurable on a per-system (or, at least, * per-mount) basis; however, that's not really best. * The best way to do it, I think, would be as an * ioctl; this would restrict it to the uid running * program, or root, which seems a reasonable compromise. * However, the number of applications for this is * minimal, if it can't be seen in the filesytem space, * and doint it as an ioctl makes it somewhat less * useful due to the, well, inelegance. * */ struct vnode * procfs_findtextvp(struct proc *p) { return (p->p_textvp); }
