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performance issues. 1) The pmap module has had too many inlines, and so the object file is simply bigger than it needs to be. Some common code is also merged into subroutines. 2) Removal of some *evil* PHYS_TO_VM_PAGE macro calls. Unfortunately, a few have needed to be added also. The removal caused the need for more vm_page_lookups. I added lookup hints to minimize the need for the page table lookup operations. 3) Removal of some bogus performance improvements, that mostly made the code more complex (tracking individual page table page updates unnecessarily). Those improvements actually hurt 386 processors perf (not that people who worry about perf use 386 processors anymore :-)). 4) Changed pv queue manipulations/structures to be TAILQ's. 5) The pv queue code has had some performance problems since day one. Some significant scalability issues are resolved by threading the pv entries from the pmap AND the physical address instead of just the physical address. This makes certain pmap operations run much faster. This does not affect most micro-benchmarks, but should help loaded system performance *significantly*. DG helped and came up with most of the solution for this one. 6) Most if not all pmap bit operations follow the pattern: pmap_test_bit(); pmap_clear_bit(); That made for twice the necessary pv list traversal. The pmap interface now supports only pmap_tc_bit type operations: pmap_[test/clear]_modified, pmap_[test/clear]_referenced. Additionally, the modified routine now takes a vm_page_t arg instead of a phys address. This eliminates a PHYS_TO_VM_PAGE operation. 7) Several rewrites of routines that contain redundant code to use common routines, so that there is a greater likelihood of keeping the cache footprint smaller.
617 lines
15 KiB
C
617 lines
15 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 1.44 1996/07/12 04:11:37 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/malloc.h>
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#include <sys/namei.h>
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#include <sys/sysent.h>
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#include <sys/syslog.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 <vm/vm_prot.h>
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#include <vm/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 <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, retval)
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struct proc *p;
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register struct execve_args *uap;
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int *retval;
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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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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->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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if (imgp->vp == NULL) {
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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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* Check file permissions (also 'opens' file)
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*/
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error = exec_check_permissions(imgp);
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/*
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* Lose the lock on the vnode. It's no longer needed, and must not
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* exist for the pagefault paging to work below.
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*/
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VOP_UNLOCK(imgp->vp);
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if (error)
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goto exec_fail_dealloc;
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/*
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* Map the image header (first page) of the file into
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* kernel address space
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*/
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error = vm_mmap(exech_map, /* map */
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(vm_offset_t *)&imgp->image_header, /* address */
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PAGE_SIZE, /* size */
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VM_PROT_READ, /* protection */
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VM_PROT_READ, /* max protection */
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0, /* flags */
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(caddr_t)imgp->vp, /* vnode */
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0); /* offset */
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if (error) {
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uprintf("mmap failed: %d\n",error);
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goto exec_fail_dealloc;
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}
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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 vnode and name buffer */
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vrele(ndp->ni_vp);
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FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI);
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if (vm_map_remove(exech_map, (vm_offset_t)imgp->image_header,
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(vm_offset_t)imgp->image_header + PAGE_SIZE))
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panic("execve: header dealloc failed (1)");
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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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/* 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. Disallow if the process is
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* being traced.
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*/
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if ((attr.va_mode & (VSUID | VSGID)) &&
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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_groups[0] = attr.va_gid;
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p->p_flag |= P_SUGID;
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} else {
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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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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 (vm_map_remove(exech_map, (vm_offset_t)imgp->image_header,
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(vm_offset_t)imgp->image_header + PAGE_SIZE))
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panic("execve: header dealloc failed (2)");
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vrele(ndp->ni_vp);
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FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI);
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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 (imgp->image_header && imgp->image_header != (char *)-1)
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if (vm_map_remove(exech_map, (vm_offset_t)imgp->image_header,
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(vm_offset_t)imgp->image_header + PAGE_SIZE))
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panic("execve: header dealloc failed (3)");
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if (ndp->ni_vp)
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vrele(ndp->ni_vp);
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FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI);
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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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imgp->vmspace_destroyed = 1;
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/* Blow away entire process VM */
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if (vmspace->vm_shm)
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shmexit(imgp->proc);
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vm_map_remove_userspace(&vmspace->vm_map);
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/* Allocate a new stack */
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error = vm_map_find(&vmspace->vm_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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* 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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* 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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while ((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 ((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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}
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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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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,
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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->envc++;
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}
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}
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return (0);
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}
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/*
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* Copy strings out to the new process address space, constructing
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* new arg and env vector tables. Return a pointer to the base
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* so that it can be used as the initial stack pointer.
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*/
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int *
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exec_copyout_strings(imgp)
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struct image_params *imgp;
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{
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int argc, envc;
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char **vectp;
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char *stringp, *destp;
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int *stack_base;
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struct ps_strings *arginfo;
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int szsigcode;
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/*
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* Calculate string base and vector table pointers.
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* Also deal with signal trampoline code for this exec type.
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*/
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arginfo = PS_STRINGS;
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szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
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destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
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roundup((ARG_MAX - imgp->stringspace), sizeof(char *));
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/*
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* install sigcode
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*/
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if (szsigcode)
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copyout(imgp->proc->p_sysent->sv_sigcode,
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((caddr_t)arginfo - szsigcode), szsigcode);
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/*
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* If we have a valid auxargs ptr, prepare some room
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* on the stack.
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*/
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if (imgp->auxargs)
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/*
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* The '+ 2' is for the null pointers at the end of each of the
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* arg and env vector sets, and 'AT_COUNT*2' is room for the
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* ELF Auxargs data.
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*/
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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;
|
|
|
|
/*
|
|
* Check number of open-for-writes on the file and deny execution
|
|
* if there are any.
|
|
*/
|
|
if (vp->v_writecount) {
|
|
return (ETXTBSY);
|
|
}
|
|
|
|
/* 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);
|
|
|
|
/*
|
|
* Disable setuid/setgid if the filesystem prohibits it or if
|
|
* the process is being traced.
|
|
*/
|
|
if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED))
|
|
attr->va_mode &= ~(VSUID | VSGID);
|
|
|
|
/*
|
|
* Check for execute permission to file based on current credentials.
|
|
* Then call filesystem specific open routine (which does nothing
|
|
* in the general case).
|
|
*/
|
|
error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);
|
|
if (error)
|
|
return (error);
|
|
|
|
error = VOP_OPEN(vp, FREAD, p->p_ucred, p);
|
|
if (error)
|
|
return (error);
|
|
|
|
return (0);
|
|
}
|