sys/kern/imgact_resident.c

   1 /*
   2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/kern/imgact_resident.c,v 1.17 2007/04/30 07:18:53 dillon Exp $
  35  */
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/kernel.h>
  40 #include <sys/sysproto.h>
  41 #include <sys/exec.h>
  42 #include <sys/imgact.h>
  43 #include <sys/imgact_aout.h>
  44 #include <sys/mman.h>
  45 #include <sys/proc.h>
  46 #include <sys/priv.h>
  47 #include <sys/resourcevar.h>
  48 #include <sys/sysent.h>
  49 #include <sys/systm.h>
  50 #include <sys/stat.h>
  51 #include <sys/vnode.h>
  52 #include <sys/inflate.h>
  53 #include <sys/sysctl.h>
  54 #include <sys/lock.h>
  55 #include <sys/resident.h>
  56
  57 #include <vm/vm.h>
  58 #include <vm/vm_param.h>
  59 #include <vm/pmap.h>
  60 #include <vm/vm_map.h>
  61 #include <vm/vm_kern.h>
  62 #include <vm/vm_extern.h>
  63
  64 #include <sys/sysref2.h>
  65 #include <sys/mplock2.h>
  66
  67 static int exec_res_id = 0;
  68
  69 static TAILQ_HEAD(,vmresident) exec_res_list;
  70
  71 static MALLOC_DEFINE(M_EXEC_RES, "vmresident", "resident execs");
  72
  73 /* lockmgr lock for protecting the exec_res_list */
  74 static struct lock exec_list_lock;
  75
  76 static void
  77 vm_resident_init(void *__dummy)
  78 {
  79         lockinit(&exec_list_lock, "vmres", 0, 0);
  80         TAILQ_INIT(&exec_res_list);
  81 }
  82 SYSINIT(vmres, SI_BOOT1_LOCK, SI_ORDER_ANY, vm_resident_init, 0);
  83
  84 static int
  85 fill_xresident(struct vmresident *vr, struct xresident *in, struct thread *td)
  86 {
  87         struct stat st;
  88         struct vnode *vrtmp;
  89         int error = 0;
  90
  91         vrtmp = vr->vr_vnode;
  92
  93         in->res_entry_addr = vr->vr_entry_addr;
  94         in->res_id = vr->vr_id;
  95         if (vrtmp) {
  96                 char *freepath, *fullpath;
  97                 error = vn_fullpath(td->td_proc, vrtmp, &fullpath, &freepath);
  98                 if (error != 0) {
  99                         /* could not retrieve cached path, return zero'ed string */
 100                         bzero(in->res_file, MAXPATHLEN);
 101                         error = 0;
 102                 } else {
 103                         strlcpy(in->res_file, fullpath, sizeof(in->res_file));
 104                         kfree(freepath, M_TEMP);
 105                 }
 106
 107                 /* indicate that we are using the vnode */
 108                 error = vget(vrtmp, LK_EXCLUSIVE);
 109                 if (error)
 110                         goto done;
 111
 112                 /* retrieve underlying stat information and release vnode */
 113                 error = vn_stat(vrtmp, &st, td->td_ucred);
 114                 vput(vrtmp);
 115                 if (error)
 116                         goto done;
 117
 118                 in->res_stat = st;
 119         }
 120
 121 done:
 122         if (error)
 123                 kprintf("fill_xresident, error = %d\n", error);
 124         return (error);
 125 }
 126
 127 static int
 128 sysctl_vm_resident(SYSCTL_HANDLER_ARGS)
 129 {
 130         struct vmresident *vmres;
 131         struct thread *td;
 132         int error;
 133         int count;
 134
 135         /* only super-user should call this sysctl */
 136         td = req->td;
 137         if ((priv_check(td, PRIV_VM_RESIDENT)) != 0)
 138                 return EPERM;
 139
 140         error = count = 0;
 141
 142         if (exec_res_id == 0)
 143             return error;
 144
 145         /* client queried for number of resident binaries */
 146         if (!req->oldptr)
 147             return SYSCTL_OUT(req, 0, exec_res_id);
 148
 149         lockmgr(&exec_list_lock, LK_SHARED);
 150         TAILQ_FOREACH(vmres, &exec_res_list, vr_link) {
 151                 struct xresident xres;
 152                 error = fill_xresident(vmres, &xres, td);
 153                 if (error != 0)
 154                         break;
 155
 156                 error = SYSCTL_OUT(req, (void *)&xres,
 157                                 sizeof(struct xresident));
 158                 if (error != 0)
 159                         break;
 160         }
 161         lockmgr(&exec_list_lock, LK_RELEASE);
 162
 163         return (error);
 164 }
 165 SYSCTL_PROC(_vm, OID_AUTO, resident, CTLTYPE_OPAQUE|CTLFLAG_RD, 0, 0,
 166   sysctl_vm_resident, "S,xresident", "resident executables (sys/resident.h)");
 167
 168 int
 169 exec_resident_imgact(struct image_params *imgp)
 170 {
 171         struct vmresident *vmres;
 172
 173         /*
 174          * resident image activator
 175          */
 176         if ((vmres = imgp->vp->v_resident) == NULL)
 177             return(-1);
 178         exec_new_vmspace(imgp, vmres->vr_vmspace);
 179         imgp->resident = 1;
 180         imgp->interpreted = 0;
 181         imgp->proc->p_sysent = vmres->vr_sysent;
 182         imgp->entry_addr = vmres->vr_entry_addr;
 183         return(0);
 184 }
 185
 186 /*
 187  * exec_sys_register(entry)
 188  *
 189  * Register ourselves for resident execution.  Only root (i.e. a process with
 190  * PRIV_VM_RESIDENT credentials) can do this.  This
 191  * will snapshot the vmspace and cause future exec's of the specified binary
 192  * to use the snapshot directly rather then load & relocate a new copy.
 193  *
 194  * MPALMOSTSAFE
 195  */
 196 int
 197 sys_exec_sys_register(struct exec_sys_register_args *uap)
 198 {
 199     struct thread *td = curthread;
 200     struct vmresident *vmres;
 201     struct vnode *vp;
 202     struct proc *p;
 203     int error;
 204
 205     p = td->td_proc;
 206     error = priv_check_cred(td->td_ucred, PRIV_VM_RESIDENT, 0);
 207     if (error)
 208         return(error);
 209
 210     get_mplock();
 211
 212     if ((vp = p->p_textvp) == NULL) {
 213         rel_mplock();
 214         return(ENOENT);
 215     }
 216     if (vp->v_resident) {
 217         rel_mplock();
 218         return(EEXIST);
 219     }
 220     vhold(vp);
 221     vmres = kmalloc(sizeof(*vmres), M_EXEC_RES, M_WAITOK);
 222     vp->v_resident = vmres;
 223     vmres->vr_vnode = vp;
 224     vmres->vr_sysent = p->p_sysent;
 225     vmres->vr_id = ++exec_res_id;
 226     vmres->vr_entry_addr = (intptr_t)uap->entry;
 227     vmres->vr_vmspace = vmspace_fork(p->p_vmspace); /* XXX order */
 228     pmap_pinit2(vmspace_pmap(vmres->vr_vmspace));
 229
 230     lockmgr(&exec_list_lock, LK_EXCLUSIVE);
 231     TAILQ_INSERT_TAIL(&exec_res_list, vmres, vr_link);
 232     lockmgr(&exec_list_lock, LK_RELEASE);
 233
 234     rel_mplock();
 235     return(0);
 236 }
 237
 238 /*
 239  * exec_sys_unregister(id)
 240  *
 241  *      Unregister the specified id.  If an id of -1 is used unregister
 242  *      the registration associated with the current process.  An id of -2
 243  *      unregisters everything.
 244  *
 245  * MPALMOSTSAFE
 246  */
 247 int
 248 sys_exec_sys_unregister(struct exec_sys_unregister_args *uap)
 249 {
 250     struct thread *td = curthread;
 251     struct vmresident *vmres;
 252     struct proc *p;
 253     int error;
 254     int id;
 255     int count;
 256
 257     p = td->td_proc;
 258     error = priv_check_cred(td->td_ucred, PRIV_VM_RESIDENT, 0);
 259     if (error)
 260         return(error);
 261
 262     /*
 263      * If id is -1, unregister ourselves
 264      */
 265     get_mplock();
 266     if ((id = uap->id) == -1 && p->p_textvp && p->p_textvp->v_resident)
 267         id = p->p_textvp->v_resident->vr_id;
 268
 269     /*
 270      * Look for the registration
 271      */
 272     error = ENOENT;
 273     count = 0;
 274
 275     lockmgr(&exec_list_lock, LK_EXCLUSIVE);
 276 restart:
 277     TAILQ_FOREACH(vmres, &exec_res_list, vr_link) {
 278         if (id == -2 || vmres->vr_id == id) {
 279             TAILQ_REMOVE(&exec_res_list, vmres, vr_link);
 280             if (vmres->vr_vnode) {
 281                 vmres->vr_vnode->v_resident = NULL;
 282                 vdrop(vmres->vr_vnode);
 283                 vmres->vr_vnode = NULL;
 284             }
 285             if (vmres->vr_vmspace) {
 286                 sysref_put(&vmres->vr_vmspace->vm_sysref);
 287                 vmres->vr_vmspace = NULL;
 288             }
 289             kfree(vmres, M_EXEC_RES);
 290             exec_res_id--;
 291             error = 0;
 292             ++count;
 293             goto restart;
 294         }
 295     }
 296     lockmgr(&exec_list_lock, LK_RELEASE);
 297     rel_mplock();
 298     if (error == 0)
 299         uap->sysmsg_result = count;
 300     return(error);
 301 }
 302