841 lines
20 KiB
C
841 lines
20 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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* $FreeBSD$
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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/mutex.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 <vm/vm.h>
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#include <vm/vm_param.h>
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#include <sys/lock.h>
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#include <vm/pmap.h>
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#include <vm/vm_page.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_pager.h>
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#include <machine/reg.h>
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MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
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static register_t *exec_copyout_strings __P((struct image_params *));
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/* XXX This should be vm_size_t. */
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static u_long ps_strings = PS_STRINGS;
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SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, "");
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/* XXX This should be vm_size_t. */
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static u_long usrstack = USRSTACK;
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SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, "");
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u_long ps_arg_cache_limit = PAGE_SIZE / 16;
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SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
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&ps_arg_cache_limit, 0, "");
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int ps_argsopen = 1;
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SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, "");
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/*
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* Each of the items is a pointer to a `const struct execsw', hence the
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* double pointer here.
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*/
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static const struct execsw **execsw;
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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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register_t *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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int (*img_first) __P((struct image_params *));
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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->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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imgp->vp = NULL;
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imgp->firstpage = NULL;
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imgp->ps_strings = 0;
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imgp->auxarg_size = 0;
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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 + PAGE_SIZE);
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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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imgp->image_header = imgp->stringbase + 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,
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ARG_MAX + PAGE_SIZE);
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goto exec_fail;
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}
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imgp->vp = ndp->ni_vp;
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imgp->fname = uap->fname;
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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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error = exec_map_first_page(imgp);
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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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* If the current process has a special image activator it
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* wants to try first, call it. For example, emulating shell
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* scripts differently.
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*/
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error = -1;
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if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
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error = img_first(imgp);
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/*
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* Loop through the list of image activators, calling each one.
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* An activator returns -1 if there is no match, 0 on success,
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* and an error otherwise.
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*/
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for (i = 0; error == -1 && execsw[i]; ++i) {
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if (execsw[i]->ex_imgact == NULL ||
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execsw[i]->ex_imgact == img_first) {
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continue;
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}
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error = (*execsw[i]->ex_imgact)(imgp);
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}
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if (error) {
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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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* Special interpreter operation, cleanup and loop up to try to
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* activate the interpreter.
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*/
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if (imgp->interpreted) {
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exec_unmap_first_page(imgp);
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/* free name buffer and old vnode */
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NDFREE(ndp, NDF_ONLY_PNBUF);
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vrele(ndp->ni_vp);
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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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/*
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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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/* Stop profiling */
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stopprofclock(p);
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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 its own resources back
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*/
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PROC_LOCK(p);
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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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PROC_UNLOCK(p);
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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)) {
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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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change_euid(p, 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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setugidsafety(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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PROC_UNLOCK(p);
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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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* notify others that we exec'd
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*/
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PROC_LOCK(p);
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KNOTE(&p->p_klist, NOTE_EXEC);
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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 values passed into the program in registers. */
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setregs(p, imgp->entry_addr, (u_long)(uintptr_t)stack_base,
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imgp->ps_strings);
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/* Free any previous argument cache */
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if (p->p_args && --p->p_args->ar_ref == 0)
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FREE(p->p_args, M_PARGS);
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p->p_args = NULL;
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/* Cache arguments if they fit inside our allowance */
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i = imgp->endargs - imgp->stringbase;
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if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
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PROC_UNLOCK(p);
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MALLOC(p->p_args, struct pargs *, sizeof(struct pargs) + i,
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M_PARGS, M_WAITOK);
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KASSERT(p->p_args != NULL, ("malloc of p_args failed"));
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PROC_LOCK(p);
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p->p_args->ar_ref = 1;
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p->p_args->ar_length = i;
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bcopy(imgp->stringbase, p->p_args->ar_args, i);
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}
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PROC_UNLOCK(p);
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exec_fail_dealloc:
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/*
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* free various allocated resources
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*/
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if (imgp->firstpage)
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exec_unmap_first_page(imgp);
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if (imgp->stringbase != NULL)
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kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase,
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ARG_MAX + PAGE_SIZE);
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if (imgp->vp) {
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NDFREE(ndp, NDF_ONLY_PNBUF);
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vrele(imgp->vp);
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}
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if (error == 0)
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return (0);
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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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int
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exec_map_first_page(imgp)
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struct image_params *imgp;
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{
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int s, rv, i;
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int initial_pagein;
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vm_page_t ma[VM_INITIAL_PAGEIN];
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vm_object_t object;
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if (imgp->firstpage) {
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exec_unmap_first_page(imgp);
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}
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VOP_GETVOBJECT(imgp->vp, &object);
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s = splvm();
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ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
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if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
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initial_pagein = VM_INITIAL_PAGEIN;
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if (initial_pagein > object->size)
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initial_pagein = object->size;
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for (i = 1; i < initial_pagein; i++) {
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if ((ma[i] = vm_page_lookup(object, i)) != NULL) {
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if ((ma[i]->flags & PG_BUSY) || ma[i]->busy)
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break;
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if (ma[i]->valid)
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break;
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vm_page_busy(ma[i]);
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} else {
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ma[i] = vm_page_alloc(object, i, VM_ALLOC_NORMAL);
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if (ma[i] == NULL)
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break;
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}
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}
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initial_pagein = i;
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rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
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ma[0] = vm_page_lookup(object, 0);
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if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || (ma[0]->valid == 0)) {
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if (ma[0]) {
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vm_page_protect(ma[0], VM_PROT_NONE);
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vm_page_free(ma[0]);
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}
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splx(s);
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return EIO;
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}
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}
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vm_page_wire(ma[0]);
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vm_page_wakeup(ma[0]);
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splx(s);
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pmap_kenter((vm_offset_t) imgp->image_header, VM_PAGE_TO_PHYS(ma[0]));
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imgp->firstpage = ma[0];
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return 0;
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}
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void
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exec_unmap_first_page(imgp)
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struct image_params *imgp;
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{
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if (imgp->firstpage) {
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pmap_kremove((vm_offset_t) imgp->image_header);
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vm_page_unwire(imgp->firstpage, 1);
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imgp->firstpage = NULL;
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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 - MAXSSIZ);
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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_pmap(vmspace), 0, VM_MAXUSER_ADDRESS);
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vm_map_remove(map, 0, VM_MAXUSER_ADDRESS);
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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_stack (&vmspace->vm_map, (vm_offset_t)stack_addr,
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(vm_size_t)MAXSSIZ, VM_PROT_ALL, VM_PROT_ALL, 0);
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if (error)
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return (error);
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#ifdef __ia64__
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{
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|
/*
|
|
* Allocate backing store. We really need something
|
|
* similar to vm_map_stack which can allow the backing
|
|
* store to grow upwards. This will do for now.
|
|
*/
|
|
vm_offset_t bsaddr;
|
|
bsaddr = USRSTACK - 2*MAXSSIZ;
|
|
error = vm_map_find(&vmspace->vm_map, 0, 0, &bsaddr,
|
|
4*PAGE_SIZE, 0,
|
|
VM_PROT_ALL, VM_PROT_ALL, 0);
|
|
imgp->proc->p_md.md_bspstore = bsaddr;
|
|
}
|
|
#endif
|
|
|
|
/* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
|
|
* VM_STACK case, but they are still used to monitor the size of the
|
|
* process stack so we can check the stack rlimit.
|
|
*/
|
|
vmspace->vm_ssize = SGROWSIZ >> PAGE_SHIFT;
|
|
vmspace->vm_maxsaddr = (char *)USRSTACK - MAXSSIZ;
|
|
|
|
return(0);
|
|
}
|
|
|
|
/*
|
|
* Copy out argument and environment strings from the old process
|
|
* address space into the temporary string buffer.
|
|
*/
|
|
int
|
|
exec_extract_strings(imgp)
|
|
struct image_params *imgp;
|
|
{
|
|
char **argv, **envv;
|
|
char *argp, *envp;
|
|
int error;
|
|
size_t length;
|
|
|
|
/*
|
|
* extract arguments first
|
|
*/
|
|
|
|
argv = imgp->uap->argv;
|
|
|
|
if (argv) {
|
|
argp = (caddr_t) (intptr_t) fuword(argv);
|
|
if (argp == (caddr_t) -1)
|
|
return (EFAULT);
|
|
if (argp)
|
|
argv++;
|
|
if (imgp->argv0)
|
|
argp = imgp->argv0;
|
|
if (argp) {
|
|
do {
|
|
if (argp == (caddr_t) -1)
|
|
return (EFAULT);
|
|
if ((error = copyinstr(argp, imgp->stringp,
|
|
imgp->stringspace, &length))) {
|
|
if (error == ENAMETOOLONG)
|
|
return(E2BIG);
|
|
return (error);
|
|
}
|
|
imgp->stringspace -= length;
|
|
imgp->stringp += length;
|
|
imgp->argc++;
|
|
} while ((argp = (caddr_t) (intptr_t) fuword(argv++)));
|
|
}
|
|
}
|
|
|
|
imgp->endargs = imgp->stringp;
|
|
|
|
/*
|
|
* extract environment strings
|
|
*/
|
|
|
|
envv = imgp->uap->envv;
|
|
|
|
if (envv) {
|
|
while ((envp = (caddr_t) (intptr_t) fuword(envv++))) {
|
|
if (envp == (caddr_t) -1)
|
|
return (EFAULT);
|
|
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.
|
|
*/
|
|
register_t *
|
|
exec_copyout_strings(imgp)
|
|
struct image_params *imgp;
|
|
{
|
|
int argc, envc;
|
|
char **vectp;
|
|
char *stringp, *destp;
|
|
register_t *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 = (struct ps_strings *)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) {
|
|
/*
|
|
* 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
|
|
* lower compatibility.
|
|
*/
|
|
imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size
|
|
: (AT_COUNT * 2);
|
|
/*
|
|
* The '+ 2' is for the null pointers at the end of each of
|
|
* the arg and env vector sets,and imgp->auxarg_size is room
|
|
* for argument of Runtime loader.
|
|
*/
|
|
vectp = (char **) (destp - (imgp->argc + imgp->envc + 2 +
|
|
imgp->auxarg_size) * 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 = (register_t *)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, (long)(intptr_t)vectp);
|
|
suword(&arginfo->ps_nargvstr, argc);
|
|
|
|
/*
|
|
* Fill in argument portion of vector table.
|
|
*/
|
|
for (; argc > 0; --argc) {
|
|
suword(vectp++, (long)(intptr_t)destp);
|
|
while (*stringp++ != 0)
|
|
destp++;
|
|
destp++;
|
|
}
|
|
|
|
/* a null vector table pointer separates the argp's from the envp's */
|
|
suword(vectp++, 0);
|
|
|
|
suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
|
|
suword(&arginfo->ps_nenvstr, envc);
|
|
|
|
/*
|
|
* Fill in environment portion of vector table.
|
|
*/
|
|
for (; envc > 0; --envc) {
|
|
suword(vectp++, (long)(intptr_t)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.
|
|
* Called with imgp->vp locked.
|
|
* Return 0 for success or error code on failure.
|
|
*/
|
|
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);
|
|
}
|
|
|
|
/*
|
|
* Exec handler registration
|
|
*/
|
|
int
|
|
exec_register(execsw_arg)
|
|
const struct execsw *execsw_arg;
|
|
{
|
|
const struct execsw **es, **xs, **newexecsw;
|
|
int count = 2; /* New slot and trailing NULL */
|
|
|
|
if (execsw)
|
|
for (es = execsw; *es; es++)
|
|
count++;
|
|
newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
|
|
if (newexecsw == NULL)
|
|
return ENOMEM;
|
|
xs = newexecsw;
|
|
if (execsw)
|
|
for (es = execsw; *es; es++)
|
|
*xs++ = *es;
|
|
*xs++ = execsw_arg;
|
|
*xs = NULL;
|
|
if (execsw)
|
|
free(execsw, M_TEMP);
|
|
execsw = newexecsw;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
exec_unregister(execsw_arg)
|
|
const struct execsw *execsw_arg;
|
|
{
|
|
const struct execsw **es, **xs, **newexecsw;
|
|
int count = 1;
|
|
|
|
if (execsw == NULL)
|
|
panic("unregister with no handlers left?\n");
|
|
|
|
for (es = execsw; *es; es++) {
|
|
if (*es == execsw_arg)
|
|
break;
|
|
}
|
|
if (*es == NULL)
|
|
return ENOENT;
|
|
for (es = execsw; *es; es++)
|
|
if (*es != execsw_arg)
|
|
count++;
|
|
newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
|
|
if (newexecsw == NULL)
|
|
return ENOMEM;
|
|
xs = newexecsw;
|
|
for (es = execsw; *es; es++)
|
|
if (*es != execsw_arg)
|
|
*xs++ = *es;
|
|
*xs = NULL;
|
|
if (execsw)
|
|
free(execsw, M_TEMP);
|
|
execsw = newexecsw;
|
|
return 0;
|
|
}
|