d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
651feb6587
freebsd-skq/sys/kern/kern_exec.c

1041 lines
25 KiB
C
Raw Blame History

/*
* 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 <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/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);
static register_t *exec_copyout_strings(struct image_params *);
/* 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;
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.
*/
mtx_lock(&Giant);
PROC_LOCK(p);
KASSERT((p->p_flag & P_INEXEC) == 0,
("%s(): process already has P_INEXEC flag", __func__));
if ((p->p_flag & P_KSES) && thread_single(SNGLE_EXIT)) {
PROC_UNLOCK(p);
mtx_unlock(&Giant);
return (ERESTART); /* Try again later. */
}
/* If we get here all other threads are dead. */
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;
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);
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) {
VOP_UNLOCK(imgp->vp, 0, td);
goto exec_fail_dealloc;
}
VOP_GETVOBJECT(imgp->vp, &imgp->object);
vm_object_reference(imgp->object);
error = exec_map_first_page(imgp);
VOP_UNLOCK(imgp->vp, 0, td);
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)
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);
/* free name buffer and old vnode */
NDFREE(ndp, NDF_ONLY_PNBUF);
vrele(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
*/
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);
/*
* 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;
if ((((attr.va_mode & VSUID) && oldcred->cr_uid != attr.va_uid) ||
((attr.va_mode & VSGID) && oldcred->cr_gid != attr.va_gid)) &&
(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
/* 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);
setugidsafety(td);
/*
* 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
*/
textvp = p->p_textvp;
VREF(ndp->ni_vp);
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. */
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);
#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);
vrele(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)
struct image_params *imgp;
{
int error;
struct execlist *ep;
struct proc *p = imgp->proc;
struct vmspace *vmspace = p->p_vmspace;
vm_offset_t stack_addr = USRSTACK - maxssiz;
GIANT_REQUIRED;
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) {
if (vmspace->vm_shm)
shmexit(p);
pmap_remove_pages(vmspace_pmap(vmspace), 0, VM_MAXUSER_ADDRESS);
vm_map_remove(&vmspace->vm_map, 0, VM_MAXUSER_ADDRESS);
} else {
vmspace_exec(p);
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;
int szsigcode;
/*
* Calculate string base and vector table pointers.
* Also deal with signal trampoline code for this exec type.
*/
arginfo = (struct ps_strings *)PS_STRINGS;
szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
roundup((ARG_MAX - imgp->stringspace), sizeof(char *));
/*
* install sigcode
*/
if (szsigcode)
copyout(imgp->proc->p_sysent->sv_sigcode,
((caddr_t)arginfo - szsigcode), szsigcode);
/*
* If we have a valid auxargs ptr, prepare some room
* on the stack.
*/
if (imgp->auxargs) {
/*
* 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
* lower compatibility.
*/
imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size
: (AT_COUNT * 2);
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets,and imgp->auxarg_size is room
* for argument of Runtime loader.
*/
vectp = (char **) (destp - (imgp->argc + imgp->envc + 2 +
imgp->auxarg_size) * sizeof(char *));
} else
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets
*/
vectp = (char **)
(destp - (imgp->argc + imgp->envc + 2) * sizeof(char *));
/*
* vectp also becomes our initial stack base
*/
stack_base = (register_t *)vectp;
stringp = imgp->stringbase;
argc = imgp->argc;
envc = imgp->envc;
/*
* Copy out strings - arguments and environment.
*/
copyout(stringp, destp, ARG_MAX - imgp->stringspace);
/*
* Fill in "ps_strings" struct for ps, w, etc.
*/
suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
suword(&arginfo->ps_nargvstr, argc);
/*
* Fill in argument portion of vector table.
*/
for (; argc > 0; --argc) {
suword(vectp++, (long)(intptr_t)destp);
while (*stringp++ != 0)
destp++;
destp++;
}
/* a null vector table pointer separates the argp's from the envp's */
suword(vectp++, 0);
suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
suword(&arginfo->ps_nenvstr, envc);
/*
* Fill in environment portion of vector table.
*/
for (; envc > 0; --envc) {
suword(vectp++, (long)(intptr_t)destp);
while (*stringp++ != 0)
destp++;
destp++;
}
/* end of vector table is a null pointer */
suword(vectp, 0);
return (stack_base);
}
/*
* Check permissions of file to execute.
* Called with imgp->vp locked.
* Return 0 for success or error code on failure.
*/
int
exec_check_permissions(imgp)
struct image_params *imgp;
{
struct 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);
/*
* 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);
}
Reference in New Issue View Git Blame Copy Permalink