95e5e988e0
original BSD code. The association between the vnode and the vm_object no longer includes reference counts. The major difference is that vm_object's are no longer freed gratuitiously from the vnode, and so once an object is created for the vnode, it will last as long as the vnode does. When a vnode object reference count is incremented, then the underlying vnode reference count is incremented also. The two "objects" are now more intimately related, and so the interactions are now much less complex. When vnodes are now normally placed onto the free queue with an object still attached. The rundown of the object happens at vnode rundown time, and happens with exactly the same filesystem semantics of the original VFS code. There is absolutely no need for vnode_pager_uncache and other travesties like that anymore. A side-effect of these changes is that SMP locking should be much simpler, the I/O copyin/copyout optimizations work, NFS should be more ponderable, and further work on layered filesystems should be less frustrating, because of the totally coherent management of the vnode objects and vnodes. Please be careful with your system while running this code, but I would greatly appreciate feedback as soon a reasonably possible.
670 lines
16 KiB
C
670 lines
16 KiB
C
/*
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* Copyright (c) 1993, David Greenman
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: kern_exec.c,v 1.72 1997/12/27 02:56:21 bde Exp $
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/signalvar.h>
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#include <sys/kernel.h>
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#include <sys/mount.h>
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#include <sys/filedesc.h>
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#include <sys/fcntl.h>
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#include <sys/acct.h>
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#include <sys/exec.h>
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#include <sys/imgact.h>
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#include <sys/imgact_elf.h>
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#include <sys/wait.h>
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#include <sys/proc.h>
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#include <sys/pioctl.h>
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#include <sys/malloc.h>
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#include <sys/namei.h>
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#include <sys/sysent.h>
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#include <sys/shm.h>
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#include <sys/sysctl.h>
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#include <sys/vnode.h>
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#include <sys/buf.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_prot.h>
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#include <sys/lock.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_extern.h>
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#include <vm/vm_object.h>
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#include <vm/vm_zone.h>
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#include <machine/reg.h>
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static int *exec_copyout_strings __P((struct image_params *));
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static int exec_check_permissions(struct image_params *);
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/*
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* XXX trouble here if sizeof(caddr_t) != sizeof(int), other parts
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* of the sysctl code also assumes this, and sizeof(int) == sizeof(long).
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*/
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static struct ps_strings *ps_strings = PS_STRINGS;
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SYSCTL_INT(_kern, KERN_PS_STRINGS, ps_strings, 0, &ps_strings, 0, "");
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static caddr_t usrstack = (caddr_t)USRSTACK;
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SYSCTL_INT(_kern, KERN_USRSTACK, usrstack, 0, &usrstack, 0, "");
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/*
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* execsw_set is constructed for us by the linker. Each of the items
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* is a pointer to a `const struct execsw', hence the double pointer here.
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*/
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static const struct execsw **execsw =
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(const struct execsw **)&execsw_set.ls_items[0];
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#ifndef _SYS_SYSPROTO_H_
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struct execve_args {
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char *fname;
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char **argv;
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char **envv;
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};
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#endif
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/*
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* execve() system call.
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*/
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int
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execve(p, uap)
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struct proc *p;
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register struct execve_args *uap;
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{
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struct nameidata nd, *ndp;
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int *stack_base;
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int error, len, i;
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struct image_params image_params, *imgp;
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struct vattr attr;
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struct buf *bp = NULL;
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imgp = &image_params;
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/*
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* Initialize part of the common data
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*/
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imgp->proc = p;
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imgp->uap = uap;
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imgp->attr = &attr;
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imgp->image_header = NULL;
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imgp->argc = imgp->envc = 0;
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imgp->argv0 = NULL;
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imgp->entry_addr = 0;
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imgp->vmspace_destroyed = 0;
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imgp->interpreted = 0;
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imgp->interpreter_name[0] = '\0';
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imgp->auxargs = NULL;
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/*
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* Allocate temporary demand zeroed space for argument and
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* environment strings
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*/
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imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX);
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if (imgp->stringbase == NULL) {
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error = ENOMEM;
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goto exec_fail;
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}
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imgp->stringp = imgp->stringbase;
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imgp->stringspace = ARG_MAX;
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/*
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* Translate the file name. namei() returns a vnode pointer
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* in ni_vp amoung other things.
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*/
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ndp = &nd;
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NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME,
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UIO_USERSPACE, uap->fname, p);
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interpret:
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error = namei(ndp);
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if (error) {
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kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX);
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goto exec_fail;
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}
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imgp->vp = ndp->ni_vp;
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/*
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* Check file permissions (also 'opens' file)
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*/
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error = exec_check_permissions(imgp);
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if (error) {
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VOP_UNLOCK(imgp->vp, 0, p);
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goto exec_fail_dealloc;
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}
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/*
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* Get the image header, which we define here as meaning the first
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* page of the executable.
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*/
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if (imgp->vp->v_object && imgp->vp->v_mount &&
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imgp->vp->v_mount->mnt_stat.f_iosize >= PAGE_SIZE &&
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imgp->vp->v_object->un_pager.vnp.vnp_size >=
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imgp->vp->v_mount->mnt_stat.f_iosize) {
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/*
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* Get a buffer with (at least) the first page.
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*/
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error = bread(imgp->vp, 0, imgp->vp->v_mount->mnt_stat.f_iosize,
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p->p_ucred, &bp);
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imgp->image_header = bp->b_data;
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} else {
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int resid;
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/*
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* The filesystem block size is too small, so do this the hard
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* way. Malloc some space and read PAGE_SIZE worth of the image
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* header into it.
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*/
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imgp->image_header = malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
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error = vn_rdwr(UIO_READ, imgp->vp,
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(void *)imgp->image_header, PAGE_SIZE, 0,
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UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p);
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/*
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* Clear out any remaining junk.
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*/
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if (!error && resid)
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bzero((char *)imgp->image_header + PAGE_SIZE - resid, resid);
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}
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VOP_UNLOCK(imgp->vp, 0, p);
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if (error)
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goto exec_fail_dealloc;
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/*
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* Loop through list of image activators, calling each one.
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* If there is no match, the activator returns -1. If there
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* is a match, but there was an error during the activation,
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* the error is returned. Otherwise 0 means success. If the
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* image is interpreted, loop back up and try activating
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* the interpreter.
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*/
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for (i = 0; execsw[i]; ++i) {
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if (execsw[i]->ex_imgact)
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error = (*execsw[i]->ex_imgact)(imgp);
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else
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continue;
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if (error == -1)
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continue;
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if (error)
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goto exec_fail_dealloc;
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if (imgp->interpreted) {
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/* free old bp/image_header */
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if (bp != NULL) {
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brelse(bp);
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bp = NULL;
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} else
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free((void *)imgp->image_header, M_TEMP);
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imgp->image_header = NULL;
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/* free old vnode and name buffer */
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vrele(ndp->ni_vp);
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zfree(namei_zone, ndp->ni_cnd.cn_pnbuf);
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/* set new name to that of the interpreter */
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NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME,
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UIO_SYSSPACE, imgp->interpreter_name, p);
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goto interpret;
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}
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break;
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}
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/* If we made it through all the activators and none matched, exit. */
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if (error == -1) {
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error = ENOEXEC;
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goto exec_fail_dealloc;
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}
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/*
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* Copy out strings (args and env) and initialize stack base
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*/
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stack_base = exec_copyout_strings(imgp);
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p->p_vmspace->vm_minsaddr = (char *)stack_base;
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/*
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* If custom stack fixup routine present for this process
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* let it do the stack setup.
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* Else stuff argument count as first item on stack
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*/
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if (p->p_sysent->sv_fixup)
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(*p->p_sysent->sv_fixup)(&stack_base, imgp);
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else
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suword(--stack_base, imgp->argc);
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/*
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* For security and other reasons, the file descriptor table cannot
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* be shared after an exec.
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*/
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if (p->p_fd->fd_refcnt > 1) {
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struct filedesc *tmp;
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tmp = fdcopy(p);
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fdfree(p);
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p->p_fd = tmp;
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}
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/* close files on exec */
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fdcloseexec(p);
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/* reset caught signals */
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execsigs(p);
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/* name this process - nameiexec(p, ndp) */
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len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN);
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bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len);
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p->p_comm[len] = 0;
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/*
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* mark as execed, wakeup the process that vforked (if any) and tell
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* it that it now has it's own resources back
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*/
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p->p_flag |= P_EXEC;
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if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
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p->p_flag &= ~P_PPWAIT;
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wakeup((caddr_t)p->p_pptr);
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}
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/*
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* Implement image setuid/setgid.
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*
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* Don't honor setuid/setgid if the filesystem prohibits it or if
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* the process is being traced.
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*/
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if ((attr.va_mode & VSUID && p->p_ucred->cr_uid != attr.va_uid ||
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attr.va_mode & VSGID && p->p_ucred->cr_gid != attr.va_gid) &&
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(imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
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(p->p_flag & P_TRACED) == 0) {
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/*
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* Turn off syscall tracing for set-id programs, except for
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* root.
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*/
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if (p->p_tracep && suser(p->p_ucred, &p->p_acflag)) {
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p->p_traceflag = 0;
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vrele(p->p_tracep);
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p->p_tracep = NULL;
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}
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/*
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* Set the new credentials.
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*/
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p->p_ucred = crcopy(p->p_ucred);
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if (attr.va_mode & VSUID)
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p->p_ucred->cr_uid = attr.va_uid;
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if (attr.va_mode & VSGID)
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p->p_ucred->cr_gid = attr.va_gid;
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setsugid(p);
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} else {
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if (p->p_ucred->cr_uid == p->p_cred->p_ruid &&
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p->p_ucred->cr_gid == p->p_cred->p_rgid)
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p->p_flag &= ~P_SUGID;
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}
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/*
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* Implement correct POSIX saved-id behavior.
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*/
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p->p_cred->p_svuid = p->p_ucred->cr_uid;
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p->p_cred->p_svgid = p->p_ucred->cr_gid;
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/*
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* Store the vp for use in procfs
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*/
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if (p->p_textvp) /* release old reference */
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vrele(p->p_textvp);
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VREF(ndp->ni_vp);
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p->p_textvp = ndp->ni_vp;
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/*
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* If tracing the process, trap to debugger so breakpoints
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* can be set before the program executes.
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*/
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STOPEVENT(p, S_EXEC, 0);
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if (p->p_flag & P_TRACED)
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psignal(p, SIGTRAP);
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/* clear "fork but no exec" flag, as we _are_ execing */
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p->p_acflag &= ~AFORK;
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/* Set entry address */
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setregs(p, imgp->entry_addr, (u_long)stack_base);
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/*
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* free various allocated resources
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*/
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kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX);
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if (bp != NULL)
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brelse(bp);
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else if (imgp->image_header != NULL)
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free((void *)imgp->image_header, M_TEMP);
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vrele(ndp->ni_vp);
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zfree(namei_zone, ndp->ni_cnd.cn_pnbuf);
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return (0);
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exec_fail_dealloc:
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if (imgp->stringbase != NULL)
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kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX);
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if (bp != NULL)
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brelse(bp);
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else if (imgp->image_header != NULL)
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free((void *)imgp->image_header, M_TEMP);
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if (ndp->ni_vp) {
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vrele(ndp->ni_vp);
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zfree(namei_zone, ndp->ni_cnd.cn_pnbuf);
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}
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exec_fail:
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if (imgp->vmspace_destroyed) {
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/* sorry, no more process anymore. exit gracefully */
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exit1(p, W_EXITCODE(0, SIGABRT));
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/* NOT REACHED */
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return(0);
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} else {
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return(error);
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}
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}
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/*
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* Destroy old address space, and allocate a new stack
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* The new stack is only SGROWSIZ large because it is grown
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* automatically in trap.c.
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*/
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int
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exec_new_vmspace(imgp)
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struct image_params *imgp;
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{
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int error;
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struct vmspace *vmspace = imgp->proc->p_vmspace;
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caddr_t stack_addr = (caddr_t) (USRSTACK - SGROWSIZ);
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vm_map_t map = &vmspace->vm_map;
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imgp->vmspace_destroyed = 1;
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/*
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* Blow away entire process VM, if address space not shared,
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* otherwise, create a new VM space so that other threads are
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* not disrupted
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*/
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if (vmspace->vm_refcnt == 1) {
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if (vmspace->vm_shm)
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shmexit(imgp->proc);
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pmap_remove_pages(&vmspace->vm_pmap, 0, USRSTACK);
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vm_map_remove(map, 0, USRSTACK);
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} else {
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vmspace_exec(imgp->proc);
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vmspace = imgp->proc->p_vmspace;
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map = &vmspace->vm_map;
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}
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/* Allocate a new stack */
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error = vm_map_find(map, NULL, 0, (vm_offset_t *)&stack_addr,
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SGROWSIZ, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
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if (error)
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return(error);
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vmspace->vm_ssize = SGROWSIZ >> PAGE_SHIFT;
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/* Initialize maximum stack address */
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vmspace->vm_maxsaddr = (char *)USRSTACK - MAXSSIZ;
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return(0);
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}
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|
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/*
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* Copy out argument and environment strings from the old process
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* address space into the temporary string buffer.
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*/
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int
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exec_extract_strings(imgp)
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struct image_params *imgp;
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{
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char **argv, **envv;
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char *argp, *envp;
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int error, length;
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|
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/*
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* extract arguments first
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*/
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argv = imgp->uap->argv;
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if (argv) {
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argp = (caddr_t) fuword(argv);
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if (argp == (caddr_t) -1)
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return (EFAULT);
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if (argp)
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argv++;
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if (imgp->argv0)
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argp = imgp->argv0;
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if (argp) {
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do {
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if (argp == (caddr_t) -1)
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return (EFAULT);
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if ((error = copyinstr(argp, imgp->stringp,
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imgp->stringspace, &length))) {
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if (error == ENAMETOOLONG)
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return(E2BIG);
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return (error);
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}
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imgp->stringspace -= length;
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imgp->stringp += length;
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imgp->argc++;
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} while ((argp = (caddr_t) fuword(argv++)));
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}
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}
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|
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/*
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* extract environment strings
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*/
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envv = imgp->uap->envv;
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|
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if (envv) {
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while ((envp = (caddr_t) fuword(envv++))) {
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if (envp == (caddr_t) -1)
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return (EFAULT);
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if ((error = copyinstr(envp, imgp->stringp,
|
|
imgp->stringspace, &length))) {
|
|
if (error == ENAMETOOLONG)
|
|
return(E2BIG);
|
|
return (error);
|
|
}
|
|
imgp->stringspace -= length;
|
|
imgp->stringp += length;
|
|
imgp->envc++;
|
|
}
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Copy strings out to the new process address space, constructing
|
|
* new arg and env vector tables. Return a pointer to the base
|
|
* so that it can be used as the initial stack pointer.
|
|
*/
|
|
int *
|
|
exec_copyout_strings(imgp)
|
|
struct image_params *imgp;
|
|
{
|
|
int argc, envc;
|
|
char **vectp;
|
|
char *stringp, *destp;
|
|
int *stack_base;
|
|
struct ps_strings *arginfo;
|
|
int szsigcode;
|
|
|
|
/*
|
|
* Calculate string base and vector table pointers.
|
|
* Also deal with signal trampoline code for this exec type.
|
|
*/
|
|
arginfo = PS_STRINGS;
|
|
szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
|
|
destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
|
|
roundup((ARG_MAX - imgp->stringspace), sizeof(char *));
|
|
|
|
/*
|
|
* install sigcode
|
|
*/
|
|
if (szsigcode)
|
|
copyout(imgp->proc->p_sysent->sv_sigcode,
|
|
((caddr_t)arginfo - szsigcode), szsigcode);
|
|
|
|
/*
|
|
* If we have a valid auxargs ptr, prepare some room
|
|
* on the stack.
|
|
*/
|
|
if (imgp->auxargs)
|
|
/*
|
|
* The '+ 2' is for the null pointers at the end of each of the
|
|
* arg and env vector sets, and 'AT_COUNT*2' is room for the
|
|
* ELF Auxargs data.
|
|
*/
|
|
vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 +
|
|
AT_COUNT*2) * sizeof(char*));
|
|
else
|
|
/*
|
|
* The '+ 2' is for the null pointers at the end of each of the
|
|
* arg and env vector sets
|
|
*/
|
|
vectp = (char **)
|
|
(destp - (imgp->argc + imgp->envc + 2) * sizeof(char*));
|
|
|
|
/*
|
|
* vectp also becomes our initial stack base
|
|
*/
|
|
stack_base = (int *)vectp;
|
|
|
|
stringp = imgp->stringbase;
|
|
argc = imgp->argc;
|
|
envc = imgp->envc;
|
|
|
|
/*
|
|
* Copy out strings - arguments and environment.
|
|
*/
|
|
copyout(stringp, destp, ARG_MAX - imgp->stringspace);
|
|
|
|
/*
|
|
* Fill in "ps_strings" struct for ps, w, etc.
|
|
*/
|
|
suword(&arginfo->ps_argvstr, (int)vectp);
|
|
suword(&arginfo->ps_nargvstr, argc);
|
|
|
|
/*
|
|
* Fill in argument portion of vector table.
|
|
*/
|
|
for (; argc > 0; --argc) {
|
|
suword(vectp++, (int)destp);
|
|
while (*stringp++ != 0)
|
|
destp++;
|
|
destp++;
|
|
}
|
|
|
|
/* a null vector table pointer seperates the argp's from the envp's */
|
|
suword(vectp++, 0);
|
|
|
|
suword(&arginfo->ps_envstr, (int)vectp);
|
|
suword(&arginfo->ps_nenvstr, envc);
|
|
|
|
/*
|
|
* Fill in environment portion of vector table.
|
|
*/
|
|
for (; envc > 0; --envc) {
|
|
suword(vectp++, (int)destp);
|
|
while (*stringp++ != 0)
|
|
destp++;
|
|
destp++;
|
|
}
|
|
|
|
/* end of vector table is a null pointer */
|
|
suword(vectp, 0);
|
|
|
|
return (stack_base);
|
|
}
|
|
|
|
/*
|
|
* Check permissions of file to execute.
|
|
* Return 0 for success or error code on failure.
|
|
*/
|
|
static int
|
|
exec_check_permissions(imgp)
|
|
struct image_params *imgp;
|
|
{
|
|
struct proc *p = imgp->proc;
|
|
struct vnode *vp = imgp->vp;
|
|
struct vattr *attr = imgp->attr;
|
|
int error;
|
|
|
|
/* Get file attributes */
|
|
error = VOP_GETATTR(vp, attr, p->p_ucred, p);
|
|
if (error)
|
|
return (error);
|
|
|
|
/*
|
|
* 1) Check if file execution is disabled for the filesystem that this
|
|
* file resides on.
|
|
* 2) Insure that at least one execute bit is on - otherwise root
|
|
* will always succeed, and we don't want to happen unless the
|
|
* file really is executable.
|
|
* 3) Insure that the file is a regular file.
|
|
*/
|
|
if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
|
|
((attr->va_mode & 0111) == 0) ||
|
|
(attr->va_type != VREG)) {
|
|
return (EACCES);
|
|
}
|
|
|
|
/*
|
|
* Zero length files can't be exec'd
|
|
*/
|
|
if (attr->va_size == 0)
|
|
return (ENOEXEC);
|
|
|
|
/*
|
|
* Check for execute permission to file based on current credentials.
|
|
*/
|
|
error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);
|
|
if (error)
|
|
return (error);
|
|
|
|
/*
|
|
* Check number of open-for-writes on the file and deny execution
|
|
* if there are any.
|
|
*/
|
|
if (vp->v_writecount)
|
|
return (ETXTBSY);
|
|
|
|
/*
|
|
* Call filesystem specific open routine (which does nothing in the
|
|
* general case).
|
|
*/
|
|
error = VOP_OPEN(vp, FREAD, p->p_ucred, p);
|
|
if (error)
|
|
return (error);
|
|
|
|
return (0);
|
|
}
|