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freebsd-nq/sys/kern/kern_exec.c
Jake Burkholder f36ba45234 Added fields for VM_MIN_ADDRESS, PS_STRINGS and stack protections to 
sysentvec.  Initialized all fields of all sysentvecs, which will allow
them to be used instead of constants in more places.  Provided stack
fixup routines for emulations that previously used the default.
2002-09-01 21:41:24 +00:00

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/*
* Copyright (c) 1993, David Greenman
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include "opt_ktrace.h"
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysproto.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
#include <sys/mac.h>
#include <sys/mount.h>
#include <sys/filedesc.h>
#include <sys/fcntl.h>
#include <sys/acct.h>
#include <sys/exec.h>
#include <sys/imgact.h>
#include <sys/imgact_elf.h>
#include <sys/wait.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/pioctl.h>
#include <sys/namei.h>
#include <sys/sysent.h>
#include <sys/shm.h>
#include <sys/sysctl.h>
#include <sys/user.h>
#include <sys/vnode.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <machine/reg.h>
MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
static MALLOC_DEFINE(M_ATEXEC, "atexec", "atexec callback");
/*
* callout list for things to do at exec time
*/
struct execlist {
execlist_fn function;
TAILQ_ENTRY(execlist) next;
};
TAILQ_HEAD(exec_list_head, execlist);
static struct exec_list_head exec_list = TAILQ_HEAD_INITIALIZER(exec_list);
/* XXX This should be vm_size_t. */
static u_long ps_strings = PS_STRINGS;
SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings,
0, "");
/* XXX This should be vm_size_t. */
static u_long usrstack = USRSTACK;
SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, "");
u_long ps_arg_cache_limit = PAGE_SIZE / 16;
SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
&ps_arg_cache_limit, 0, "");
int ps_argsopen = 1;
SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, "");
#ifdef __ia64__
/* XXX HACK */
static int regstkpages = 256;
SYSCTL_INT(_machdep, OID_AUTO, regstkpages, CTLFLAG_RW, &regstkpages, 0, "");
#endif
/*
* Each of the items is a pointer to a `const struct execsw', hence the
* double pointer here.
*/
static const struct execsw **execsw;
#ifndef _SYS_SYSPROTO_H_
struct execve_args {
char *fname;
char **argv;
char **envv;
};
#endif
/*
* execve() system call.
*
* MPSAFE
*/
int
execve(td, uap)
struct thread *td;
register struct execve_args *uap;
{
struct proc *p = td->td_proc;
struct nameidata nd, *ndp;
struct ucred *newcred = NULL, *oldcred;
struct uidinfo *euip;
register_t *stack_base;
int error, len, i;
struct image_params image_params, *imgp;
struct vattr attr;
int (*img_first)(struct image_params *);
struct pargs *oldargs = NULL, *newargs = NULL;
struct procsig *oldprocsig, *newprocsig;
#ifdef KTRACE
struct vnode *tracevp = NULL;
#endif
struct vnode *textvp = NULL;
int credential_changing;
int textset;
imgp = &image_params;
/*
* Lock the process and set the P_INEXEC flag to indicate that
* it should be left alone until we're done here. This is
* necessary to avoid race conditions - e.g. in ptrace() -
* that might allow a local user to illicitly obtain elevated
* privileges.
*/
PROC_LOCK(p);
KASSERT((p->p_flag & P_INEXEC) == 0,
("%s(): process already has P_INEXEC flag", __func__));
if (p->p_flag & P_KSES) {
if (thread_single(SNGLE_EXIT)) {
PROC_UNLOCK(p);
return (ERESTART); /* Try again later. */
}
/*
* If we get here all other threads are dead,
* so unset the associated flags and lose KSE mode.
*/
p->p_flag &= ~P_KSES;
td->td_flags &= ~TDF_UNBOUND;
thread_single_end();
}
p->p_flag |= P_INEXEC;
PROC_UNLOCK(p);
/*
* Initialize part of the common data
*/
imgp->proc = p;
imgp->uap = uap;
imgp->attr = &attr;
imgp->argc = imgp->envc = 0;
imgp->argv0 = NULL;
imgp->entry_addr = 0;
imgp->vmspace_destroyed = 0;
imgp->interpreted = 0;
imgp->interpreter_name[0] = '\0';
imgp->auxargs = NULL;
imgp->vp = NULL;
imgp->object = NULL;
imgp->firstpage = NULL;
imgp->ps_strings = 0;
imgp->auxarg_size = 0;
/*
* Allocate temporary demand zeroed space for argument and
* environment strings
*/
imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX +
PAGE_SIZE);
if (imgp->stringbase == NULL) {
error = ENOMEM;
mtx_lock(&Giant);
goto exec_fail;
}
imgp->stringp = imgp->stringbase;
imgp->stringspace = ARG_MAX;
imgp->image_header = imgp->stringbase + ARG_MAX;
/*
* Translate the file name. namei() returns a vnode pointer
* in ni_vp amoung other things.
*/
ndp = &nd;
NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME,
UIO_USERSPACE, uap->fname, td);
mtx_lock(&Giant);
interpret:
error = namei(ndp);
if (error) {
kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase,
ARG_MAX + PAGE_SIZE);
goto exec_fail;
}
imgp->vp = ndp->ni_vp;
imgp->fname = uap->fname;
/*
* Check file permissions (also 'opens' file)
*/
error = exec_check_permissions(imgp);
if (error)
goto exec_fail_dealloc;
if (VOP_GETVOBJECT(imgp->vp, &imgp->object) == 0)
vm_object_reference(imgp->object);
/*
* Set VV_TEXT now so no one can write to the executable while we're
* activating it.
*
* Remember if this was set before and unset it in case this is not
* actually an executable image.
*/
textset = imgp->vp->v_vflag & VV_TEXT;
imgp->vp->v_vflag |= VV_TEXT;
error = exec_map_first_page(imgp);
if (error)
goto exec_fail_dealloc;
/*
* If the current process has a special image activator it
* wants to try first, call it. For example, emulating shell
* scripts differently.
*/
error = -1;
if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
error = img_first(imgp);
/*
* Loop through the list of image activators, calling each one.
* An activator returns -1 if there is no match, 0 on success,
* and an error otherwise.
*/
for (i = 0; error == -1 && execsw[i]; ++i) {
if (execsw[i]->ex_imgact == NULL ||
execsw[i]->ex_imgact == img_first) {
continue;
}
error = (*execsw[i]->ex_imgact)(imgp);
}
if (error) {
if (error == -1) {
if (textset == 0)
imgp->vp->v_vflag &= ~VV_TEXT;
error = ENOEXEC;
}
goto exec_fail_dealloc;
}
/*
* Special interpreter operation, cleanup and loop up to try to
* activate the interpreter.
*/
if (imgp->interpreted) {
exec_unmap_first_page(imgp);
/*
* VV_TEXT needs to be unset for scripts. There is a short
* period before we determine that something is a script where
* VV_TEXT will be set. The vnode lock is held over this
* entire period so nothing should illegitimately be blocked.
*/
imgp->vp->v_vflag &= ~VV_TEXT;
/* free name buffer and old vnode */
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(ndp->ni_vp);
vm_object_deallocate(imgp->object);
imgp->object = NULL;
/* set new name to that of the interpreter */
NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME,
UIO_SYSSPACE, imgp->interpreter_name, td);
goto interpret;
}
/*
* Copy out strings (args and env) and initialize stack base
*/
if (p->p_sysent->sv_copyout_strings)
stack_base = (*p->p_sysent->sv_copyout_strings)(imgp);
else
stack_base = exec_copyout_strings(imgp);
/*
* If custom stack fixup routine present for this process
* let it do the stack setup.
* Else stuff argument count as first item on stack
*/
if (p->p_sysent->sv_fixup)
(*p->p_sysent->sv_fixup)(&stack_base, imgp);
else
suword(--stack_base, imgp->argc);
/*
* For security and other reasons, the file descriptor table cannot
* be shared after an exec.
*/
FILEDESC_LOCK(p->p_fd);
if (p->p_fd->fd_refcnt > 1) {
struct filedesc *tmp;
tmp = fdcopy(td);
FILEDESC_UNLOCK(p->p_fd);
fdfree(td);
p->p_fd = tmp;
} else
FILEDESC_UNLOCK(p->p_fd);
/*
* Malloc things before we need locks.
*/
newcred = crget();
euip = uifind(attr.va_uid);
i = imgp->endargs - imgp->stringbase;
if (ps_arg_cache_limit >= i + sizeof(struct pargs))
newargs = pargs_alloc(i);
/* close files on exec */
fdcloseexec(td);
/* Get a reference to the vnode prior to locking the proc */
VREF(ndp->ni_vp);
/*
* For security and other reasons, signal handlers cannot
* be shared after an exec. The new process gets a copy of the old
* handlers. In execsigs(), the new process will have its signals
* reset.
*/
PROC_LOCK(p);
mp_fixme("procsig needs a lock");
if (p->p_procsig->ps_refcnt > 1) {
oldprocsig = p->p_procsig;
PROC_UNLOCK(p);
MALLOC(newprocsig, struct procsig *, sizeof(struct procsig),
M_SUBPROC, M_WAITOK);
bcopy(oldprocsig, newprocsig, sizeof(*newprocsig));
newprocsig->ps_refcnt = 1;
oldprocsig->ps_refcnt--;
PROC_LOCK(p);
p->p_procsig = newprocsig;
if (p->p_sigacts == &p->p_uarea->u_sigacts)
panic("shared procsig but private sigacts?");
p->p_uarea->u_sigacts = *p->p_sigacts;
p->p_sigacts = &p->p_uarea->u_sigacts;
}
/* Stop profiling */
stopprofclock(p);
/* reset caught signals */
execsigs(p);
/* name this process - nameiexec(p, ndp) */
len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN);
bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len);
p->p_comm[len] = 0;
/*
* mark as execed, wakeup the process that vforked (if any) and tell
* it that it now has its own resources back
*/
p->p_flag |= P_EXEC;
if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
p->p_flag &= ~P_PPWAIT;
wakeup(p->p_pptr);
}
/*
* Implement image setuid/setgid.
*
* Don't honor setuid/setgid if the filesystem prohibits it or if
* the process is being traced.
*/
oldcred = p->p_ucred;
credential_changing = 0;
credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid !=
attr.va_uid;
credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid !=
attr.va_gid;
if (credential_changing &&
(imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
(p->p_flag & P_TRACED) == 0) {
/*
* Turn off syscall tracing for set-id programs, except for
* root. Record any set-id flags first to make sure that
* we do not regain any tracing during a possible block.
*/
setsugid(p);
#ifdef KTRACE
if (p->p_tracep && suser_cred(oldcred, PRISON_ROOT)) {
mtx_lock(&ktrace_mtx);
p->p_traceflag = 0;
tracevp = p->p_tracep;
p->p_tracep = NULL;
mtx_unlock(&ktrace_mtx);
}
#endif
/* Close any file descriptors 0..2 that reference procfs */
setugidsafety(td);
/* Make sure file descriptors 0..2 are in use. */
error = fdcheckstd(td);
if (error != 0)
goto done1;
/*
* Set the new credentials.
*/
crcopy(newcred, oldcred);
if (attr.va_mode & VSUID)
change_euid(newcred, euip);
if (attr.va_mode & VSGID)
change_egid(newcred, attr.va_gid);
/*
* Implement correct POSIX saved-id behavior.
*/
change_svuid(newcred, newcred->cr_uid);
change_svgid(newcred, newcred->cr_gid);
p->p_ucred = newcred;
newcred = NULL;
} else {
if (oldcred->cr_uid == oldcred->cr_ruid &&
oldcred->cr_gid == oldcred->cr_rgid)
p->p_flag &= ~P_SUGID;
/*
* Implement correct POSIX saved-id behavior.
*
* XXX: It's not clear that the existing behavior is
* POSIX-compliant. A number of sources indicate that the
* saved uid/gid should only be updated if the new ruid is
* not equal to the old ruid, or the new euid is not equal
* to the old euid and the new euid is not equal to the old
* ruid. The FreeBSD code always updates the saved uid/gid.
* Also, this code uses the new (replaced) euid and egid as
* the source, which may or may not be the right ones to use.
*/
if (oldcred->cr_svuid != oldcred->cr_uid ||
oldcred->cr_svgid != oldcred->cr_gid) {
crcopy(newcred, oldcred);
change_svuid(newcred, newcred->cr_uid);
change_svgid(newcred, newcred->cr_gid);
p->p_ucred = newcred;
newcred = NULL;
}
}
/*
* Store the vp for use in procfs. This vnode was referenced prior
* to locking the proc lock.
*/
textvp = p->p_textvp;
p->p_textvp = ndp->ni_vp;
/*
* Notify others that we exec'd, and clear the P_INEXEC flag
* as we're now a bona fide freshly-execed process.
*/
KNOTE(&p->p_klist, NOTE_EXEC);
p->p_flag &= ~P_INEXEC;
/*
* If tracing the process, trap to debugger so breakpoints
* can be set before the program executes.
*/
_STOPEVENT(p, S_EXEC, 0);
if (p->p_flag & P_TRACED)
psignal(p, SIGTRAP);
/* clear "fork but no exec" flag, as we _are_ execing */
p->p_acflag &= ~AFORK;
/* Free any previous argument cache */
oldargs = p->p_args;
p->p_args = NULL;
/* Set values passed into the program in registers. */
if (p->p_sysent->sv_setregs)
(*p->p_sysent->sv_setregs)(td, imgp->entry_addr,
(u_long)(uintptr_t)stack_base, imgp->ps_strings);
else
exec_setregs(td, imgp->entry_addr,
(u_long)(uintptr_t)stack_base, imgp->ps_strings);
/* Cache arguments if they fit inside our allowance */
if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
bcopy(imgp->stringbase, newargs->ar_args, i);
p->p_args = newargs;
newargs = NULL;
}
done1:
PROC_UNLOCK(p);
/*
* Free any resources malloc'd earlier that we didn't use.
*/
uifree(euip);
if (newcred == NULL)
crfree(oldcred);
else
crfree(newcred);
/*
* Handle deferred decrement of ref counts.
*/
if (textvp != NULL)
vrele(textvp);
if (ndp->ni_vp && error != 0)
vrele(ndp->ni_vp);
#ifdef KTRACE
if (tracevp != NULL)
vrele(tracevp);
#endif
if (oldargs != NULL)
pargs_drop(oldargs);
if (newargs != NULL)
pargs_drop(newargs);
exec_fail_dealloc:
/*
* free various allocated resources
*/
if (imgp->firstpage)
exec_unmap_first_page(imgp);
if (imgp->stringbase != NULL)
kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase,
ARG_MAX + PAGE_SIZE);
if (imgp->vp) {
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(imgp->vp);
}
if (imgp->object)
vm_object_deallocate(imgp->object);
if (error == 0)
goto done2;
exec_fail:
/* we're done here, clear P_INEXEC */
PROC_LOCK(p);
p->p_flag &= ~P_INEXEC;
PROC_UNLOCK(p);
if (imgp->vmspace_destroyed) {
/* sorry, no more process anymore. exit gracefully */
exit1(td, W_EXITCODE(0, SIGABRT));
/* NOT REACHED */
error = 0;
}
done2:
mtx_unlock(&Giant);
return (error);
}
int
exec_map_first_page(imgp)
struct image_params *imgp;
{
int rv, i;
int initial_pagein;
vm_page_t ma[VM_INITIAL_PAGEIN];
vm_object_t object;
GIANT_REQUIRED;
if (imgp->firstpage) {
exec_unmap_first_page(imgp);
}
VOP_GETVOBJECT(imgp->vp, &object);
ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
initial_pagein = VM_INITIAL_PAGEIN;
if (initial_pagein > object->size)
initial_pagein = object->size;
for (i = 1; i < initial_pagein; i++) {
if ((ma[i] = vm_page_lookup(object, i)) != NULL) {
if ((ma[i]->flags & PG_BUSY) || ma[i]->busy)
break;
if (ma[i]->valid)
break;
vm_page_busy(ma[i]);
} else {
ma[i] = vm_page_alloc(object, i,
VM_ALLOC_NORMAL);
if (ma[i] == NULL)
break;
}
}
initial_pagein = i;
rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
ma[0] = vm_page_lookup(object, 0);
if ((rv != VM_PAGER_OK) || (ma[0] == NULL) ||
(ma[0]->valid == 0)) {
if (ma[0]) {
vm_page_lock_queues();
vm_page_protect(ma[0], VM_PROT_NONE);
vm_page_free(ma[0]);
vm_page_unlock_queues();
}
return (EIO);
}
}
vm_page_lock_queues();
vm_page_wire(ma[0]);
vm_page_wakeup(ma[0]);
vm_page_unlock_queues();
pmap_qenter((vm_offset_t)imgp->image_header, ma, 1);
imgp->firstpage = ma[0];
return (0);
}
void
exec_unmap_first_page(imgp)
struct image_params *imgp;
{
GIANT_REQUIRED;
if (imgp->firstpage) {
pmap_qremove((vm_offset_t)imgp->image_header, 1);
vm_page_lock_queues();
vm_page_unwire(imgp->firstpage, 1);
vm_page_unlock_queues();
imgp->firstpage = NULL;
}
}
/*
* Destroy old address space, and allocate a new stack
* The new stack is only SGROWSIZ large because it is grown
* automatically in trap.c.
*/
int
exec_new_vmspace(imgp, minuser, maxuser, stack_addr)
struct image_params *imgp;
vm_offset_t minuser, maxuser, stack_addr;
{
int error;
struct execlist *ep;
struct proc *p = imgp->proc;
struct vmspace *vmspace = p->p_vmspace;
GIANT_REQUIRED;
stack_addr = stack_addr - maxssiz;
imgp->vmspace_destroyed = 1;
/*
* Perform functions registered with at_exec().
*/
TAILQ_FOREACH(ep, &exec_list, next)
(*ep->function)(p);
/*
* Blow away entire process VM, if address space not shared,
* otherwise, create a new VM space so that other threads are
* not disrupted
*/
if (vmspace->vm_refcnt == 1 &&
vm_map_min(&vmspace->vm_map) == minuser &&
vm_map_max(&vmspace->vm_map) == maxuser) {
if (vmspace->vm_shm)
shmexit(p);
pmap_remove_pages(vmspace_pmap(vmspace), minuser, maxuser);
vm_map_remove(&vmspace->vm_map, minuser, maxuser);
} else {
vmspace_exec(p, minuser, maxuser);
vmspace = p->p_vmspace;
}
/* Allocate a new stack */
error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz,
VM_PROT_ALL, VM_PROT_ALL, 0);
if (error)
return (error);
#ifdef __ia64__
{
/*
* 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,
regstkpages * PAGE_SIZE, 0, VM_PROT_ALL, VM_PROT_ALL, 0);
FIRST_THREAD_IN_PROC(p)->td_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;
struct proc *p;
int szsigcode;
/*
* Calculate string base and vector table pointers.
* Also deal with signal trampoline code for this exec type.
*/
p = imgp->proc;
szsigcode = 0;
arginfo = (struct ps_strings *)PS_STRINGS;
if (p->p_sysent->sv_szsigcode != NULL)
szsigcode = *(p->p_sysent->sv_szsigcode);
destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
roundup((ARG_MAX - imgp->stringspace), sizeof(char *));
/*
* install sigcode
*/
if (szsigcode)
copyout(p->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 vnode *vp = imgp->vp;
struct vattr *attr = imgp->attr;
struct thread *td;
int error;
td = curthread; /* XXXKSE */
#ifdef MAC
error = mac_check_vnode_exec(td->td_ucred, imgp->vp);
if (error)
return (error);
#endif
/* Get file attributes */
error = VOP_GETATTR(vp, attr, td->td_ucred, td);
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, td->td_ucred, td);
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, td->td_ucred, td);
return (error);
}
/*
* 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);
}
int
at_exec(function)
execlist_fn function;
{
struct execlist *ep;
#ifdef INVARIANTS
/* Be noisy if the programmer has lost track of things */
if (rm_at_exec(function))
printf("WARNING: exec callout entry (%p) already present\n",
function);
#endif
ep = malloc(sizeof(*ep), M_ATEXEC, M_NOWAIT);
if (ep == NULL)
return (ENOMEM);
ep->function = function;
TAILQ_INSERT_TAIL(&exec_list, ep, next);
return (0);
}
/*
* Scan the exec callout list for the given item and remove it.
* Returns the number of items removed (0 or 1)
*/
int
rm_at_exec(function)
execlist_fn function;
{
struct execlist *ep;
TAILQ_FOREACH(ep, &exec_list, next) {
if (ep->function == function) {
TAILQ_REMOVE(&exec_list, ep, next);
free(ep, M_ATEXEC);
return (1);
}
}
return (0);
}
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