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/sysmsg.h>
41 #include <sys/exec.h>
42 #include <sys/imgact.h>
43 #include <sys/mman.h>
44 #include <sys/proc.h>
45 #include <sys/caps.h>
46 #include <sys/resourcevar.h>
47 #include <sys/sysent.h>
48 #include <sys/stat.h>
49 #include <sys/vnode.h>
50 #include <sys/sysctl.h>
51 #include <sys/lock.h>
52 #include <sys/resident.h>
53 #include <sys/malloc.h>
54
55 #include <vm/vm.h>
56 #include <vm/vm_param.h>
57 #include <vm/pmap.h>
58 #include <vm/vm_map.h>
59 #include <vm/vm_kern.h>
60 #include <vm/vm_extern.h>
61
62 static int exec_res_id = 0;
63
64 static TAILQ_HEAD(,vmresident) exec_res_list;
65
66 static MALLOC_DEFINE(M_EXEC_RES, "vmresident", "resident execs");
67
68 /* lockmgr lock for protecting the exec_res_list */
69 static struct lock exec_list_lock;
70
71 static void
vm_resident_init(void * __dummy)72 vm_resident_init(void *__dummy)
73 {
74 lockinit(&exec_list_lock, "vmres", 0, 0);
75 TAILQ_INIT(&exec_res_list);
76 }
77 SYSINIT(vmres, SI_BOOT1_LOCK, SI_ORDER_ANY, vm_resident_init, 0);
78
79 static int
fill_xresident(struct vmresident * vr,struct xresident * in,struct thread * td)80 fill_xresident(struct vmresident *vr, struct xresident *in, struct thread *td)
81 {
82 struct stat st;
83 struct vnode *vrtmp;
84 int error = 0;
85
86 vrtmp = vr->vr_vnode;
87
88 in->res_entry_addr = vr->vr_entry_addr;
89 in->res_id = vr->vr_id;
90 if (vrtmp) {
91 char *freepath, *fullpath;
92 error = vn_fullpath(td->td_proc, vrtmp, &fullpath, &freepath, 0);
93 if (error != 0) {
94 /* could not retrieve cached path, return zero'ed string */
95 bzero(in->res_file, MAXPATHLEN);
96 error = 0;
97 } else {
98 strlcpy(in->res_file, fullpath, sizeof(in->res_file));
99 kfree(freepath, M_TEMP);
100 }
101
102 /* indicate that we are using the vnode */
103 error = vget(vrtmp, LK_EXCLUSIVE);
104 if (error)
105 goto done;
106
107 /* retrieve underlying stat information and release vnode */
108 error = vn_stat(vrtmp, &st, td->td_ucred);
109 vput(vrtmp);
110 if (error)
111 goto done;
112
113 in->res_stat = st;
114 }
115
116 done:
117 if (error)
118 kprintf("fill_xresident, error = %d\n", error);
119 return (error);
120 }
121
122 static int
sysctl_vm_resident(SYSCTL_HANDLER_ARGS)123 sysctl_vm_resident(SYSCTL_HANDLER_ARGS)
124 {
125 struct vmresident *vmres;
126 struct thread *td;
127 int error;
128 int count;
129
130 /* only super-user should call this sysctl */
131 td = req->td;
132 error = caps_priv_check_td(td, SYSCAP_NOVM_RESIDENT);
133 if (error)
134 return error;
135
136 count = 0;
137
138 if (exec_res_id == 0)
139 return error;
140
141 /* client queried for number of resident binaries */
142 if (!req->oldptr)
143 return SYSCTL_OUT(req, 0, exec_res_id);
144
145 lockmgr(&exec_list_lock, LK_SHARED);
146
147 TAILQ_FOREACH(vmres, &exec_res_list, vr_link) {
148 struct xresident xres;
149 error = fill_xresident(vmres, &xres, td);
150 if (error != 0)
151 break;
152
153 error = SYSCTL_OUT(req, (void *)&xres,
154 sizeof(struct xresident));
155 if (error != 0)
156 break;
157 }
158 lockmgr(&exec_list_lock, LK_RELEASE);
159
160 return (error);
161 }
162 SYSCTL_PROC(_vm, OID_AUTO, resident, CTLTYPE_OPAQUE|CTLFLAG_RD, 0, 0,
163 sysctl_vm_resident, "S,xresident", "resident executables (sys/resident.h)");
164
165 int
exec_resident_imgact(struct image_params * imgp)166 exec_resident_imgact(struct image_params *imgp)
167 {
168 struct vmresident *vmres;
169
170 /*
171 * resident image activator
172 */
173 lockmgr(&exec_list_lock, LK_SHARED);
174 if ((vmres = imgp->vp->v_resident) == NULL) {
175 lockmgr(&exec_list_lock, LK_RELEASE);
176 return(-1);
177 }
178 atomic_add_int(&vmres->vr_refs, 1);
179 lockmgr(&exec_list_lock, LK_RELEASE);
180
181 /*
182 * We want to exec the new vmspace without holding the lock to
183 * improve concurrency.
184 */
185 exec_new_vmspace(imgp, vmres->vr_vmspace);
186 imgp->resident = 1;
187 imgp->interpreted = 0;
188 imgp->proc->p_sysent = vmres->vr_sysent;
189 imgp->entry_addr = vmres->vr_entry_addr;
190 atomic_subtract_int(&vmres->vr_refs, 1);
191
192 return(0);
193 }
194
195 /*
196 * exec_sys_register(entry)
197 *
198 * Register ourselves for resident execution. Only root (i.e. a process with
199 * PRIV_VM_RESIDENT credentials) can do this. This
200 * will snapshot the vmspace and cause future exec's of the specified binary
201 * to use the snapshot directly rather then load & relocate a new copy.
202 *
203 * MPALMOSTSAFE
204 */
205 int
sys_exec_sys_register(struct sysmsg * sysmsg,const struct exec_sys_register_args * uap)206 sys_exec_sys_register(struct sysmsg *sysmsg,
207 const struct exec_sys_register_args *uap)
208 {
209 struct thread *td = curthread;
210 struct vmresident *vmres;
211 struct vnode *vp;
212 struct proc *p;
213 int error;
214
215 p = td->td_proc;
216 error = caps_priv_check_td(td, SYSCAP_NOVM_RESIDENT);
217 if (error)
218 return(error);
219
220 if ((vp = p->p_textvp) == NULL)
221 return(ENOENT);
222
223 lockmgr(&exec_list_lock, LK_EXCLUSIVE);
224
225 if (vp->v_resident) {
226 lockmgr(&exec_list_lock, LK_RELEASE);
227 return(EEXIST);
228 }
229
230 vhold(vp);
231 vmres = kmalloc(sizeof(*vmres), M_EXEC_RES, M_WAITOK | M_ZERO);
232 vmres->vr_vnode = vp;
233 vmres->vr_sysent = p->p_sysent;
234 vmres->vr_id = ++exec_res_id;
235 vmres->vr_entry_addr = (intptr_t)uap->entry;
236 vmres->vr_vmspace = vmspace_fork(p->p_vmspace, NULL, NULL); /* XXX order */
237 pmap_pinit2(vmspace_pmap(vmres->vr_vmspace));
238 vp->v_resident = vmres;
239
240 TAILQ_INSERT_TAIL(&exec_res_list, vmres, vr_link);
241 lockmgr(&exec_list_lock, LK_RELEASE);
242
243 return(0);
244 }
245
246 /*
247 * exec_sys_unregister(id)
248 *
249 * Unregister the specified id. If an id of -1 is used unregister
250 * the registration associated with the current process. An id of -2
251 * unregisters everything.
252 *
253 * MPALMOSTSAFE
254 */
255 int
sys_exec_sys_unregister(struct sysmsg * sysmsg,const struct exec_sys_unregister_args * uap)256 sys_exec_sys_unregister(struct sysmsg *sysmsg,
257 const 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 = caps_priv_check_td(td, SYSCAP_NOVM_RESIDENT);
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_rel(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 sysmsg->sysmsg_result = count;
322 return(error);
323 }
324
325