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91898abc5e
freebsd/sys/kern/kern_exec.c
David Xu 0dbb100b9b Move UPCALL related data structure out of kse, introduce a new 
data structure called kse_upcall to manage UPCALL. All KSE binding
and loaning code are gone.

A thread owns an upcall can collect all completed syscall contexts in
its ksegrp, turn itself into UPCALL mode, and takes those contexts back
to userland. Any thread without upcall structure has to export their
contexts and exit at user boundary.

Any thread running in user mode owns an upcall structure, when it enters
kernel, if the kse mailbox's current thread pointer is not NULL, then
when the thread is blocked in kernel, a new UPCALL thread is created and
the upcall structure is transfered to the new UPCALL thread. if the kse
mailbox's current thread pointer is NULL, then when a thread is blocked
in kernel, no UPCALL thread will be created.

Each upcall always has an owner thread. Userland can remove an upcall by
calling kse_exit, when all upcalls in ksegrp are removed, the group is
atomatically shutdown. An upcall owner thread also exits when process is
in exiting state. when an owner thread exits, the upcall it owns is also
removed.

KSE is a pure scheduler entity. it represents a virtual cpu. when a thread
is running, it always has a KSE associated with it. scheduler is free to
assign a KSE to thread according thread priority, if thread priority is changed,
KSE can be moved from one thread to another.

When a ksegrp is created, there is always N KSEs created in the group. the
N is the number of physical cpu in the current system. This makes it is
possible that even an userland UTS is single CPU safe, threads in kernel still
can execute on different cpu in parallel. Userland calls kse_create to add more
upcall structures into ksegrp to increase concurrent in userland itself, kernel
is not restricted by number of upcalls userland provides.

The code hasn't been tested under SMP by author due to lack of hardware.

Reviewed by: julian
2003-01-26 11:41:35 +00:00

1261 lines
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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");
static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS);
static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS);
static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS);
static int kern_execve(struct thread *td, char *fname, char **argv,
char **envv, struct mac *mac_p);
/*
* 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. */
SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD,
NULL, 0, sysctl_kern_ps_strings, "LU", "");
/* XXX This should be vm_size_t. */
SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD,
NULL, 0, sysctl_kern_usrstack, "LU", "");
SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD,
NULL, 0, sysctl_kern_stackprot, "I", "");
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
static int
sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
{
struct proc *p;
p = curproc;
return (SYSCTL_OUT(req, &p->p_sysent->sv_psstrings,
sizeof(p->p_sysent->sv_psstrings)));
}
static int
sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
{
struct proc *p;
p = curproc;
return (SYSCTL_OUT(req, &p->p_sysent->sv_usrstack,
sizeof(p->p_sysent->sv_usrstack)));
}
static int
sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
{
struct proc *p;
p = curproc;
return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
sizeof(p->p_sysent->sv_stackprot)));
}
/*
* Each of the items is a pointer to a `const struct execsw', hence the
* double pointer here.
*/
static const struct execsw **execsw;
/*
* In-kernel implementation of execve(). All arguments are assumed to be
* userspace pointers from the passed thread.
*
* MPSAFE
*/
static int
kern_execve(td, fname, argv, envv, mac_p)
struct thread *td;
char *fname;
char **argv;
char **envv;
struct mac *mac_p;
{
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;
#ifdef MAC
struct label interplabel; /* label of the interpreted vnode */
struct label execlabel; /* optional label argument */
int will_transition, interplabelvalid = 0;
#endif
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(SINGLE_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_mailbox = NULL;
thread_single_end();
}
p->p_flag |= P_INEXEC;
PROC_UNLOCK(p);
/*
* Initialize part of the common data
*/
imgp->proc = p;
imgp->userspace_argv = argv;
imgp->userspace_envv = envv;
imgp->execlabel = NULL;
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;
#ifdef MAC
error = mac_execve_enter(imgp, mac_p, &execlabel);
if (error) {
mtx_lock(&Giant);
goto exec_fail;
}
#endif
/*
* 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, 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 = 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);
#ifdef MAC
mac_init_vnode_label(&interplabel);
mac_copy_vnode_label(&ndp->ni_vp->v_label, &interplabel);
interplabelvalid = 1;
#endif
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->td_proc->p_fd);
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, 0);
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.
*
* XXXMAC: For the time being, use NOSUID to also prohibit
* transitions on the file system.
*/
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;
#ifdef MAC
will_transition = mac_execve_will_transition(oldcred, imgp->vp,
interplabelvalid ? &interplabel : NULL, imgp);
credential_changing |= will_transition;
#endif
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,
* then make sure file descriptors 0..2 are in use.
*
* setugidsafety() may call closef() and then pfind()
* which may grab the process lock.
* fdcheckstd() may call falloc() which may block to
* allocate memory, so temporarily drop the process lock.
*/
PROC_UNLOCK(p);
setugidsafety(td);
error = fdcheckstd(td);
if (error != 0)
goto done1;
PROC_LOCK(p);
/*
* 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);
#ifdef MAC
if (will_transition) {
mac_execve_transition(oldcred, newcred, imgp->vp,
interplabelvalid ? &interplabel : NULL, imgp);
}
#endif
/*
* Implement correct POSIX saved-id behavior.
*
* XXXMAC: Note that the current logic will save the
* uid and gid if a MAC domain transition occurs, even
* though maybe it shouldn't.
*/
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.
*/
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;
/* 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;
}
PROC_UNLOCK(p);
/* 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);
done1:
/*
* 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->vp) {
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(imgp->vp);
}
if (imgp->stringbase != NULL)
kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase,
ARG_MAX + PAGE_SIZE);
if (imgp->object)
vm_object_deallocate(imgp->object);
if (error == 0) {
/*
* Stop the process here if its stop event mask has
* the S_EXEC bit set.
*/
STOPEVENT(p, S_EXEC, 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 */
#ifdef MAC
mac_execve_exit(imgp);
if (interplabelvalid)
mac_destroy_vnode_label(&interplabel);
#endif
exit1(td, W_EXITCODE(0, SIGABRT));
/* NOT REACHED */
error = 0;
}
done2:
#ifdef MAC
mac_execve_exit(imgp);
if (interplabelvalid)
mac_destroy_vnode_label(&interplabel);
#endif
mtx_unlock(&Giant);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct execve_args {
char *fname;
char **argv;
char **envv;
};
#endif
/*
* MPSAFE
*/
int
execve(td, uap)
struct thread *td;
struct execve_args /* {
char *fname;
char **argv;
char **envv;
} */ *uap;
{
return (kern_execve(td, uap->fname, uap->argv, uap->envv, NULL));
}
#ifndef _SYS_SYSPROTO_H_
struct __mac_execve_args {
char *fname;
char **argv;
char **envv;
struct mac *mac_p;
};
#endif
/*
* MPSAFE
*/
int
__mac_execve(td, uap)
struct thread *td;
struct __mac_execve_args /* {
char *fname;
char **argv;
char **envv;
struct mac *mac_p;
} */ *uap;
{
#ifdef MAC
return (kern_execve(td, uap->fname, uap->argv, uap->envv,
uap->mac_p));
#else
return (ENOSYS);
#endif
}
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_lock_queues();
vm_page_busy(ma[i]);
vm_page_unlock_queues();
} 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();
pmap_remove_all(ma[0]);
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, sv)
struct image_params *imgp;
struct sysentvec *sv;
{
int error;
struct execlist *ep;
struct proc *p = imgp->proc;
struct vmspace *vmspace = p->p_vmspace;
vm_offset_t stack_addr;
vm_map_t map;
GIANT_REQUIRED;
stack_addr = sv->sv_usrstack - 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
*/
map = &vmspace->vm_map;
if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser &&
vm_map_max(map) == sv->sv_maxuser) {
shmexit(vmspace);
vm_page_lock_queues();
pmap_remove_pages(vmspace_pmap(vmspace), vm_map_min(map),
vm_map_max(map));
vm_page_unlock_queues();
vm_map_remove(map, vm_map_min(map), vm_map_max(map));
} else {
vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser);
vmspace = p->p_vmspace;
map = &vmspace->vm_map;
}
/* Allocate a new stack */
error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz,
sv->sv_stackprot, 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 = p->p_sysent->sv_usrstack - 2 * maxssiz;
error = vm_map_find(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 *)sv->sv_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->userspace_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->userspace_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 *)p->p_sysent->sv_psstrings;
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 */
/* Get file attributes */
error = VOP_GETATTR(vp, attr, td->td_ucred, td);
if (error)
return (error);
#ifdef MAC
error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp);
if (error)
return (error);
#endif
/*
* 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, 0);
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, 0);
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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