static
int
vm_region_expand( struct vm_region *vmr, unsigned npages ) {
unsigned new_pages;
int res;
unsigned i;
unsigned old_pages;
old_pages = vm_page_array_num( vmr->vmr_pages );
new_pages = npages - old_pages;
//trivial case, nothing to do.
if( new_pages == 0 )
return 0;
//see if we can back this loan with storage.
res = swap_reserve( new_pages );
if( res )
return res;
//attempt to rezize the vmr_pages array.
res = vm_page_array_setsize( vmr->vmr_pages, npages );
if( res ) {
swap_unreserve( new_pages );
return res;
}
//initialize each of the newly created vm_pages to NULL.
for( i = old_pages; i < npages; ++i )
vm_page_array_set( vmr->vmr_pages, i, NULL );
return 0;
}
/*
* kmap_alloc_wait:
*
* Allocates pageable memory from a sub-map of the kernel. If the submap
* has no room, the caller sleeps waiting for more memory in the submap.
*
* This routine may block.
*/
vm_offset_t
kmap_alloc_wait(vm_map_t map, vm_size_t size)
{
vm_offset_t addr;
size = round_page(size);
if (!swap_reserve(size))
return (0);
for (;;) {
/*
* To make this work for more than one map, use the map's lock
* to lock out sleepers/wakers.
*/
vm_map_lock(map);
if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0)
break;
/* no space now; see if we can ever get space */
if (vm_map_max(map) - vm_map_min(map) < size) {
vm_map_unlock(map);
swap_release(size);
return (0);
}
map->needs_wakeup = TRUE;
vm_map_unlock_and_wait(map, 0);
}
vm_map_insert(map, NULL, 0, addr, addr + size, VM_PROT_ALL,
VM_PROT_ALL, MAP_ACC_CHARGED);
vm_map_unlock(map);
return (addr);
}
/*
* vm_object_setsize: change the size of a vm_object.
*/
int
vm_object_setsize(struct addrspace *as, struct vm_object *vmo, unsigned npages)
{
int result;
unsigned i;
struct lpage *lp;
KASSERT(vmo != NULL);
KASSERT(vmo->vmo_lpages != NULL);
if (npages < lpage_array_num(vmo->vmo_lpages)) {
for (i=npages; i<lpage_array_num(vmo->vmo_lpages); i++) {
lp = lpage_array_get(vmo->vmo_lpages, i);
if (lp != NULL) {
KASSERT(as != NULL);
/* remove any tlb entry for this mapping */
mmu_unmap(as, vmo->vmo_base+PAGE_SIZE*i);
lpage_destroy(lp);
}
else {
swap_unreserve(1);
}
}
result = lpage_array_setsize(vmo->vmo_lpages, npages);
/* shrinking an array shouldn't fail */
KASSERT(result==0);
}
else if (npages > lpage_array_num(vmo->vmo_lpages)) {
int oldsize = lpage_array_num(vmo->vmo_lpages);
unsigned newpages = npages - oldsize;
result = swap_reserve(newpages);
if (result) {
return result;
}
result = lpage_array_setsize(vmo->vmo_lpages, npages);
if (result) {
swap_unreserve(newpages);
return result;
}
for (i=oldsize; i<npages; i++) {
lpage_array_set(vmo->vmo_lpages, i, NULL);
}
}
return 0;
}
struct vm_region *
vm_region_create( size_t npages ) {
int res;
struct vm_region *vmr;
unsigned i;
int err;
//see if we can reserve npages of swap first.
err = swap_reserve( npages );
if( err )
return NULL;
//attempt to create the vm_region
vmr = kmalloc( sizeof( struct vm_region ) );
if( vmr == NULL )
return NULL;
//create the vm_pages.
vmr->vmr_pages = vm_page_array_create();
if( vmr->vmr_pages == NULL ) {
kfree( vmr );
swap_unreserve( npages );
return NULL;
}
//set the base address to point to an invalid virtual address.
vmr->vmr_base = 0xdeadbeef;
//adjust the array to hold npages.
res = vm_page_array_setsize( vmr->vmr_pages, npages );
if( res ) {
vm_page_array_destroy( vmr->vmr_pages );
kfree( vmr );
swap_unreserve( npages );
return NULL;
}
//initialize all the pages to NULL.
for( i = 0; i < npages; ++i )
vm_page_array_set( vmr->vmr_pages, i, NULL );
return vmr;
}
/*
* vm_object_create: Allocate a new vm_object with nothing in it.
* Returns: new vm_object on success, NULL on error.
*/
struct vm_object *
vm_object_create(size_t npages)
{
struct vm_object *vmo;
unsigned i;
int result;
result = swap_reserve(npages);
if (result != 0) {
return NULL;
}
vmo = kmalloc(sizeof(struct vm_object));
if (vmo == NULL) {
swap_unreserve(npages);
return NULL;
}
vmo->vmo_lpages = lpage_array_create();
if (vmo->vmo_lpages == NULL) {
kfree(vmo);
swap_unreserve(npages);
return NULL;
}
vmo->vmo_base = 0xdeafbeef; /* make sure these */
vmo->vmo_lower_redzone = 0xdeafbeef; /* get filled in later */
/* add the requested number of zerofilled pages */
result = lpage_array_setsize(vmo->vmo_lpages, npages);
if (result) {
lpage_array_destroy(vmo->vmo_lpages);
kfree(vmo);
swap_unreserve(npages);
return NULL;
}
for (i=0; i<npages; i++) {
lpage_array_set(vmo->vmo_lpages, i, NULL);
}
return vmo;
}
int
fork1(struct thread *td, struct fork_req *fr)
{
struct proc *p1, *newproc;
struct thread *td2;
struct vmspace *vm2;
struct file *fp_procdesc;
vm_ooffset_t mem_charged;
int error, nprocs_new, ok;
static int curfail;
static struct timeval lastfail;
int flags, pages;
flags = fr->fr_flags;
pages = fr->fr_pages;
if ((flags & RFSTOPPED) != 0)
MPASS(fr->fr_procp != NULL && fr->fr_pidp == NULL);
else
MPASS(fr->fr_procp == NULL);
/* Check for the undefined or unimplemented flags. */
if ((flags & ~(RFFLAGS | RFTSIGFLAGS(RFTSIGMASK))) != 0)
return (EINVAL);
/* Signal value requires RFTSIGZMB. */
if ((flags & RFTSIGFLAGS(RFTSIGMASK)) != 0 && (flags & RFTSIGZMB) == 0)
return (EINVAL);
/* Can't copy and clear. */
if ((flags & (RFFDG|RFCFDG)) == (RFFDG|RFCFDG))
return (EINVAL);
/* Check the validity of the signal number. */
if ((flags & RFTSIGZMB) != 0 && (u_int)RFTSIGNUM(flags) > _SIG_MAXSIG)
return (EINVAL);
if ((flags & RFPROCDESC) != 0) {
/* Can't not create a process yet get a process descriptor. */
if ((flags & RFPROC) == 0)
return (EINVAL);
/* Must provide a place to put a procdesc if creating one. */
if (fr->fr_pd_fd == NULL)
return (EINVAL);
/* Check if we are using supported flags. */
if ((fr->fr_pd_flags & ~PD_ALLOWED_AT_FORK) != 0)
return (EINVAL);
}
p1 = td->td_proc;
/*
* Here we don't create a new process, but we divorce
* certain parts of a process from itself.
*/
if ((flags & RFPROC) == 0) {
if (fr->fr_procp != NULL)
*fr->fr_procp = NULL;
else if (fr->fr_pidp != NULL)
*fr->fr_pidp = 0;
return (fork_norfproc(td, flags));
}
fp_procdesc = NULL;
newproc = NULL;
vm2 = NULL;
/*
* Increment the nprocs resource before allocations occur.
* Although process entries are dynamically created, we still
* keep a global limit on the maximum number we will
* create. There are hard-limits as to the number of processes
* that can run, established by the KVA and memory usage for
* the process data.
*
* Don't allow a nonprivileged user to use the last ten
* processes; don't let root exceed the limit.
*/
nprocs_new = atomic_fetchadd_int(&nprocs, 1) + 1;
if ((nprocs_new >= maxproc - 10 && priv_check_cred(td->td_ucred,
PRIV_MAXPROC, 0) != 0) || nprocs_new >= maxproc) {
error = EAGAIN;
sx_xlock(&allproc_lock);
if (ppsratecheck(&lastfail, &curfail, 1)) {
printf("maxproc limit exceeded by uid %u (pid %d); "
"see tuning(7) and login.conf(5)\n",
td->td_ucred->cr_ruid, p1->p_pid);
}
sx_xunlock(&allproc_lock);
goto fail2;
}
/*
* If required, create a process descriptor in the parent first; we
* will abandon it if something goes wrong. We don't finit() until
* later.
*/
if (flags & RFPROCDESC) {
error = procdesc_falloc(td, &fp_procdesc, fr->fr_pd_fd,
fr->fr_pd_flags, fr->fr_pd_fcaps);
if (error != 0)
goto fail2;
}
mem_charged = 0;
if (pages == 0)
pages = kstack_pages;
/* Allocate new proc. */
newproc = uma_zalloc(proc_zone, M_WAITOK);
td2 = FIRST_THREAD_IN_PROC(newproc);
if (td2 == NULL) {
td2 = thread_alloc(pages);
if (td2 == NULL) {
error = ENOMEM;
goto fail2;
}
proc_linkup(newproc, td2);
} else {
if (td2->td_kstack == 0 || td2->td_kstack_pages != pages) {
if (td2->td_kstack != 0)
vm_thread_dispose(td2);
if (!thread_alloc_stack(td2, pages)) {
error = ENOMEM;
goto fail2;
}
}
}
if ((flags & RFMEM) == 0) {
vm2 = vmspace_fork(p1->p_vmspace, &mem_charged);
if (vm2 == NULL) {
error = ENOMEM;
goto fail2;
}
if (!swap_reserve(mem_charged)) {
/*
* The swap reservation failed. The accounting
* from the entries of the copied vm2 will be
* subtracted in vmspace_free(), so force the
* reservation there.
*/
swap_reserve_force(mem_charged);
error = ENOMEM;
goto fail2;
}
} else
vm2 = NULL;
/*
* XXX: This is ugly; when we copy resource usage, we need to bump
* per-cred resource counters.
*/
proc_set_cred_init(newproc, crhold(td->td_ucred));
/*
* Initialize resource accounting for the child process.
*/
error = racct_proc_fork(p1, newproc);
if (error != 0) {
error = EAGAIN;
goto fail1;
}
#ifdef MAC
mac_proc_init(newproc);
#endif
newproc->p_klist = knlist_alloc(&newproc->p_mtx);
STAILQ_INIT(&newproc->p_ktr);
/* We have to lock the process tree while we look for a pid. */
sx_slock(&proctree_lock);
sx_xlock(&allproc_lock);
/*
* Increment the count of procs running with this uid. Don't allow
* a nonprivileged user to exceed their current limit.
*
* XXXRW: Can we avoid privilege here if it's not needed?
*/
error = priv_check_cred(td->td_ucred, PRIV_PROC_LIMIT, 0);
if (error == 0)
ok = chgproccnt(td->td_ucred->cr_ruidinfo, 1, 0);
else {
ok = chgproccnt(td->td_ucred->cr_ruidinfo, 1,
lim_cur(td, RLIMIT_NPROC));
}
if (ok) {
do_fork(td, fr, newproc, td2, vm2, fp_procdesc);
return (0);
}
error = EAGAIN;
sx_sunlock(&proctree_lock);
sx_xunlock(&allproc_lock);
#ifdef MAC
mac_proc_destroy(newproc);
#endif
racct_proc_exit(newproc);
fail1:
crfree(newproc->p_ucred);
newproc->p_ucred = NULL;
fail2:
if (vm2 != NULL)
vmspace_free(vm2);
uma_zfree(proc_zone, newproc);
if ((flags & RFPROCDESC) != 0 && fp_procdesc != NULL) {
fdclose(td, fp_procdesc, *fr->fr_pd_fd);
fdrop(fp_procdesc, td);
}
atomic_add_int(&nprocs, -1);
pause("fork", hz / 2);
return (error);
}
