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
  66 static int exec_res_id = 0;
  67
  68 static TAILQ_HEAD(,vmresident) exec_res_list;
  69
  70 static MALLOC_DEFINE(M_EXEC_RES, "vmresident", "resident execs");
  71
  72 /* lockmgr lock for protecting the exec_res_list */
  73 static struct lock exec_list_lock;
  74
  75 static void
  76 vm_resident_init(void *__dummy)
  77 {
  78         lockinit(&exec_list_lock, "vmres", 0, 0);
  79         TAILQ_INIT(&exec_res_list);
  80 }
  81 SYSINIT(vmres, SI_BOOT1_LOCK, SI_ORDER_ANY, vm_resident_init, 0);
  82
  83 static int
  84 fill_xresident(struct vmresident *vr, struct xresident *in, struct thread *td)
  85 {
  86         struct stat st;
  87         struct vnode *vrtmp;
  88         int error = 0;
  89
  90         vrtmp = vr->vr_vnode;
  91
  92         in->res_entry_addr = vr->vr_entry_addr;
  93         in->res_id = vr->vr_id;
  94         if (vrtmp) {
  95                 char *freepath, *fullpath;
  96                 error = vn_fullpath(td->td_proc, vrtmp, &fullpath, &freepath);
  97                 if (error != 0) {
  98                         /* could not retrieve cached path, return zero'ed string */
  99                         bzero(in->res_file, MAXPATHLEN);
 100                         error = 0;
 101                 } else {
 102                         strlcpy(in->res_file, fullpath, sizeof(in->res_file));
 103                         kfree(freepath, M_TEMP);
 104                 }
 105
 106                 /* indicate that we are using the vnode */
 107                 error = vget(vrtmp, LK_EXCLUSIVE);
 108                 if (error)
 109                         goto done;
 110
 111                 /* retrieve underlying stat information and release vnode */
 112                 error = vn_stat(vrtmp, &st, td->td_proc->p_ucred);
 113                 vput(vrtmp);
 114                 if (error)
 115                         goto done;
 116
 117                 in->res_stat = st;
 118         }
 119
 120 done:
 121         if (error)
 122                 kprintf("fill_xresident, error = %d\n", error);
 123         return (error);
 124 }
 125
 126 static int
 127 sysctl_vm_resident(SYSCTL_HANDLER_ARGS)
 128 {
 129         struct vmresident *vmres;
 130         struct thread *td;
 131         int error;
 132         int count;
 133
 134         /* only super-user should call this sysctl */
 135         td = req->td;
 136         if ((priv_check(td, PRIV_VM_RESIDENT)) != 0)
 137                 return EPERM;
 138
 139         error = count = 0;
 140
 141         if (exec_res_id == 0)
 142             return error;
 143
 144         /* client queried for number of resident binaries */
 145         if (!req->oldptr)
 146             return SYSCTL_OUT(req, 0, exec_res_id);
 147
 148         lockmgr(&exec_list_lock, LK_SHARED);
 149         TAILQ_FOREACH(vmres, &exec_res_list, vr_link) {
 150                 struct xresident xres;
 151                 error = fill_xresident(vmres, &xres, td);
 152                 if (error != 0)
 153                         break;
 154
 155                 error = SYSCTL_OUT(req, (void *)&xres,
 156                                 sizeof(struct xresident));
 157                 if (error != 0)
 158                         break;
 159         }
 160         lockmgr(&exec_list_lock, LK_RELEASE);
 161
 162         return (error);
 163 }
 164 SYSCTL_PROC(_vm, OID_AUTO, resident, CTLTYPE_OPAQUE|CTLFLAG_RD, 0, 0,
 165   sysctl_vm_resident, "S,xresident", "resident executables (sys/resident.h)");
 166
 167 int
 168 exec_resident_imgact(struct image_params *imgp)
 169 {
 170         struct vmresident *vmres;
 171
 172         /*
 173          * resident image activator
 174          */
 175         if ((vmres = imgp->vp->v_resident) == NULL)
 176             return(-1);
 177         exec_new_vmspace(imgp, vmres->vr_vmspace);
 178         imgp->resident = 1;
 179         imgp->interpreted = 0;
 180         imgp->proc->p_sysent = vmres->vr_sysent;
 181         imgp->entry_addr = vmres->vr_entry_addr;
 182         return(0);
 183 }
 184
 185 /*
 186  * exec_sys_register(entry)
 187  *
 188  * Register ourselves for resident execution.  Only root (i.e. a process with
 189  * PRIV_VM_RESIDENT credentials) can do this.  This
 190  * will snapshot the vmspace and cause future exec's of the specified binary
 191  * to use the snapshot directly rather then load & relocate a new copy.
 192  */
 193 int
 194 sys_exec_sys_register(struct exec_sys_register_args *uap)
 195 {
 196     struct vmresident *vmres;
 197     struct vnode *vp;
 198     struct proc *p;
 199     int error;
 200
 201     p = curproc;
 202     if ((error = priv_check_cred(p->p_ucred, PRIV_VM_RESIDENT, 0)) != 0)
 203         return(error);
 204     if ((vp = p->p_textvp) == NULL)
 205         return(ENOENT);
 206     if (vp->v_resident)
 207         return(EEXIST);
 208     vhold(vp);
 209     vmres = kmalloc(sizeof(*vmres), M_EXEC_RES, M_WAITOK);
 210     vp->v_resident = vmres;
 211     vmres->vr_vnode = vp;
 212     vmres->vr_sysent = p->p_sysent;
 213     vmres->vr_id = ++exec_res_id;
 214     vmres->vr_entry_addr = (intptr_t)uap->entry;
 215     vmres->vr_vmspace = vmspace_fork(p->p_vmspace); /* XXX order */
 216     pmap_pinit2(vmspace_pmap(vmres->vr_vmspace));
 217
 218     lockmgr(&exec_list_lock, LK_EXCLUSIVE);
 219     TAILQ_INSERT_TAIL(&exec_res_list, vmres, vr_link);
 220     lockmgr(&exec_list_lock, LK_RELEASE);
 221
 222     return(0);
 223 }
 224
 225 /*
 226  * exec_sys_unregister(id)
 227  *
 228  *      Unregister the specified id.  If an id of -1 is used unregister
 229  *      the registration associated with the current process.  An id of -2
 230  *      unregisters everything.
 231  */
 232 int
 233 sys_exec_sys_unregister(struct exec_sys_unregister_args *uap)
 234 {
 235     struct vmresident *vmres;
 236     struct proc *p;
 237     int error;
 238     int id;
 239     int count;
 240
 241     p = curproc;
 242     if ((error = priv_check_cred(p->p_ucred, PRIV_VM_RESIDENT, 0)) != 0)
 243         return(error);
 244
 245     /*
 246      * If id is -1, unregister ourselves
 247      */
 248     if ((id = uap->id) == -1 && p->p_textvp && p->p_textvp->v_resident)
 249         id = p->p_textvp->v_resident->vr_id;
 250
 251     /*
 252      * Look for the registration
 253      */
 254     error = ENOENT;
 255     count = 0;
 256
 257     lockmgr(&exec_list_lock, LK_EXCLUSIVE);
 258 restart:
 259     TAILQ_FOREACH(vmres, &exec_res_list, vr_link) {
 260         if (id == -2 || vmres->vr_id == id) {
 261             TAILQ_REMOVE(&exec_res_list, vmres, vr_link);
 262             if (vmres->vr_vnode) {
 263                 vmres->vr_vnode->v_resident = NULL;
 264                 vdrop(vmres->vr_vnode);
 265                 vmres->vr_vnode = NULL;
 266             }
 267             if (vmres->vr_vmspace) {
 268                 sysref_put(&vmres->vr_vmspace->vm_sysref);
 269                 vmres->vr_vmspace = NULL;
 270             }
 271             kfree(vmres, M_EXEC_RES);
 272             exec_res_id--;
 273             error = 0;
 274             ++count;
 275             goto restart;
 276         }
 277     }
 278     lockmgr(&exec_list_lock, LK_RELEASE);
 279     if (error == 0)
 280         uap->sysmsg_result = count;
 281     return(error);
 282 }
 283