imgact_resident.c

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    1 /*
    2  * (MPSAFE)
    3  *
    4  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
    5  * 
    6  * This code is derived from software contributed to The DragonFly Project
    7  * by Matthew Dillon <dillon@backplane.com>
    8  * 
    9  * Redistribution and use in source and binary forms, with or without
   10  * modification, are permitted provided that the following conditions
   11  * are met:
   12  * 
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in
   17  *    the documentation and/or other materials provided with the
   18  *    distribution.
   19  * 3. Neither the name of The DragonFly Project nor the names of its
   20  *    contributors may be used to endorse or promote products derived
   21  *    from this software without specific, prior written permission.
   22  * 
   23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   24  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   26  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
   27  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   28  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
   29  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   30  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   31  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   32  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   33  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   34  * SUCH DAMAGE.
   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/stat.h>
   50 #include <sys/vnode.h>
   51 #include <sys/inflate.h>
   52 #include <sys/sysctl.h>
   53 #include <sys/lock.h>
   54 #include <sys/resident.h>
   55 
   56 #include <vm/vm.h>
   57 #include <vm/vm_param.h>
   58 #include <vm/pmap.h>
   59 #include <vm/vm_map.h>
   60 #include <vm/vm_kern.h>
   61 #include <vm/vm_extern.h>
   62 
   63 #include <sys/sysref2.h>
   64 
   65 static int exec_res_id = 0;
   66 
   67 static TAILQ_HEAD(,vmresident) exec_res_list;
   68 
   69 static MALLOC_DEFINE(M_EXEC_RES, "vmresident", "resident execs");
   70 
   71 /* lockmgr lock for protecting the exec_res_list */
   72 static struct lock exec_list_lock;
   73 
   74 static void
   75 vm_resident_init(void *__dummy)
   76 {
   77         lockinit(&exec_list_lock, "vmres", 0, 0);
   78         TAILQ_INIT(&exec_res_list);
   79 }
   80 SYSINIT(vmres, SI_BOOT1_LOCK, SI_ORDER_ANY, vm_resident_init, 0);
   81 
   82 static int
   83 fill_xresident(struct vmresident *vr, struct xresident *in, struct thread *td)
   84 {
   85         struct stat st;
   86         struct vnode *vrtmp;
   87         int error = 0;
   88 
   89         vrtmp = vr->vr_vnode;
   90 
   91         in->res_entry_addr = vr->vr_entry_addr;
   92         in->res_id = vr->vr_id;
   93         if (vrtmp) {
   94                 char *freepath, *fullpath;
   95                 error = vn_fullpath(td->td_proc, vrtmp, &fullpath, &freepath, 0);
   96                 if (error != 0) {
   97                         /* could not retrieve cached path, return zero'ed string */
   98                         bzero(in->res_file, MAXPATHLEN);
   99                         error = 0;
  100                 } else {
  101                         strlcpy(in->res_file, fullpath, sizeof(in->res_file));
  102                         kfree(freepath, M_TEMP);
  103                 }
  104 
  105                 /* indicate that we are using the vnode */
  106                 error = vget(vrtmp, LK_EXCLUSIVE);
  107                 if (error)
  108                         goto done;
  109         
  110                 /* retrieve underlying stat information and release vnode */
  111                 error = vn_stat(vrtmp, &st, td->td_ucred);
  112                 vput(vrtmp);
  113                 if (error)
  114                         goto done;
  115 
  116                 in->res_stat = st;
  117         }
  118 
  119 done:
  120         if (error)
  121                 kprintf("fill_xresident, error = %d\n", error);
  122         return (error);
  123 }
  124 
  125 static int
  126 sysctl_vm_resident(SYSCTL_HANDLER_ARGS)
  127 {
  128         struct vmresident *vmres;
  129         struct thread *td;
  130         int error;
  131         int count;
  132 
  133         /* only super-user should call this sysctl */
  134         td = req->td;
  135         if ((priv_check(td, PRIV_VM_RESIDENT)) != 0)
  136                 return EPERM;
  137 
  138         error = count = 0;
  139 
  140         if (exec_res_id == 0)
  141             return error;
  142         
  143         /* client queried for number of resident binaries */
  144         if (!req->oldptr)
  145             return SYSCTL_OUT(req, 0, exec_res_id);
  146 
  147         lockmgr(&exec_list_lock, LK_SHARED);
  148 
  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         lockmgr(&exec_list_lock, LK_SHARED);
  176         if ((vmres = imgp->vp->v_resident) == NULL) {
  177             lockmgr(&exec_list_lock, LK_RELEASE);
  178             return(-1);
  179         }
  180         atomic_add_int(&vmres->vr_refs, 1);
  181         lockmgr(&exec_list_lock, LK_RELEASE);
  182 
  183         /*
  184          * We want to exec the new vmspace without holding the lock to
  185          * improve concurrency.
  186          */
  187         exec_new_vmspace(imgp, vmres->vr_vmspace);
  188         imgp->resident = 1;
  189         imgp->interpreted = 0;
  190         imgp->proc->p_sysent = vmres->vr_sysent;
  191         imgp->entry_addr = vmres->vr_entry_addr;
  192         atomic_subtract_int(&vmres->vr_refs, 1);
  193 
  194         return(0);
  195 }
  196 
  197 /*
  198  * exec_sys_register(entry)
  199  *
  200  * Register ourselves for resident execution.  Only root (i.e. a process with
  201  * PRIV_VM_RESIDENT credentials) can do this.  This
  202  * will snapshot the vmspace and cause future exec's of the specified binary
  203  * to use the snapshot directly rather then load & relocate a new copy.
  204  *
  205  * MPALMOSTSAFE
  206  */
  207 int
  208 sys_exec_sys_register(struct exec_sys_register_args *uap)
  209 {
  210     struct thread *td = curthread;
  211     struct vmresident *vmres;
  212     struct vnode *vp;
  213     struct proc *p;
  214     int error;
  215 
  216     p = td->td_proc;
  217     error = priv_check_cred(td->td_ucred, PRIV_VM_RESIDENT, 0);
  218     if (error)
  219         return(error);
  220 
  221     if ((vp = p->p_textvp) == NULL)
  222         return(ENOENT);
  223 
  224     lockmgr(&exec_list_lock, LK_EXCLUSIVE);
  225 
  226     if (vp->v_resident) {
  227         lockmgr(&exec_list_lock, LK_RELEASE);
  228         return(EEXIST);
  229     }
  230 
  231     vhold(vp);
  232     vmres = kmalloc(sizeof(*vmres), M_EXEC_RES, M_WAITOK | M_ZERO);
  233     vmres->vr_vnode = vp;
  234     vmres->vr_sysent = p->p_sysent;
  235     vmres->vr_id = ++exec_res_id;
  236     vmres->vr_entry_addr = (intptr_t)uap->entry;
  237     vmres->vr_vmspace = vmspace_fork(p->p_vmspace); /* XXX order */
  238     pmap_pinit2(vmspace_pmap(vmres->vr_vmspace));
  239     vp->v_resident = vmres;
  240 
  241     TAILQ_INSERT_TAIL(&exec_res_list, vmres, vr_link);
  242     lockmgr(&exec_list_lock, LK_RELEASE);
  243 
  244     return(0);
  245 }
  246 
  247 /*
  248  * exec_sys_unregister(id)
  249  *
  250  *      Unregister the specified id.  If an id of -1 is used unregister
  251  *      the registration associated with the current process.  An id of -2
  252  *      unregisters everything.
  253  *
  254  * MPALMOSTSAFE
  255  */
  256 int
  257 sys_exec_sys_unregister(struct exec_sys_unregister_args *uap)
  258 {
  259     struct thread *td = curthread;
  260     struct vmresident *vmres;
  261     struct proc *p;
  262     int error;
  263     int id;
  264     int count;
  265 
  266     p = td->td_proc;
  267     error = priv_check_cred(td->td_ucred, PRIV_VM_RESIDENT, 0);
  268     if (error)
  269         return(error);
  270 
  271     /*
  272      * If id is -1, unregister ourselves
  273      */
  274     lockmgr(&exec_list_lock, LK_EXCLUSIVE);
  275 
  276     if ((id = uap->id) == -1 && p->p_textvp && p->p_textvp->v_resident)
  277         id = p->p_textvp->v_resident->vr_id;
  278 
  279     /*
  280      * Look for the registration
  281      */
  282     error = ENOENT;
  283     count = 0;
  284 
  285 restart:
  286     TAILQ_FOREACH(vmres, &exec_res_list, vr_link) {
  287         if (id == -2 || vmres->vr_id == id) {
  288             /*
  289              * Check race against exec
  290              */
  291             if (vmres->vr_refs) {
  292                 lockmgr(&exec_list_lock, LK_RELEASE);
  293                 tsleep(vmres, 0, "vmres", 1);
  294                 lockmgr(&exec_list_lock, LK_EXCLUSIVE);
  295                 goto restart;
  296             }
  297 
  298             /*
  299              * Remove it
  300              */
  301             TAILQ_REMOVE(&exec_res_list, vmres, vr_link);
  302             if (vmres->vr_vnode) {
  303                 vmres->vr_vnode->v_resident = NULL;
  304                 vdrop(vmres->vr_vnode);
  305                 vmres->vr_vnode = NULL;
  306             }
  307             if (vmres->vr_vmspace) {
  308                 vmspace_free(vmres->vr_vmspace);
  309                 vmres->vr_vmspace = NULL;
  310             }
  311             kfree(vmres, M_EXEC_RES);
  312             exec_res_id--;
  313             error = 0;
  314             ++count;
  315             goto restart;
  316         }
  317     }
  318     lockmgr(&exec_list_lock, LK_RELEASE);
  319 
  320     if (error == 0)
  321         uap->sysmsg_result = count;
  322     return(error);
  323 }
  324
Cache object: 2510fda3a1a7a9ec0764fa49a9328345
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FreeBSD/Linux Kernel Cross Reference sys/kern/imgact_resident.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/imgact_resident.c
