xref: /dragonfly/sys/kern/imgact_resident.c (revision 8a0bcd56) 
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  * $DragonFly: src/sys/kern/imgact_resident.c,v 1.17 2007/04/30 07:18:53 dillon Exp $
37  */
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/kernel.h>
42 #include <sys/sysproto.h>
43 #include <sys/exec.h>
44 #include <sys/imgact.h>
45 #include <sys/imgact_aout.h>
46 #include <sys/mman.h>
47 #include <sys/proc.h>
48 #include <sys/priv.h>
49 #include <sys/resourcevar.h>
50 #include <sys/sysent.h>
51 #include <sys/systm.h>
52 #include <sys/stat.h>
53 #include <sys/vnode.h>
54 #include <sys/inflate.h>
55 #include <sys/sysctl.h>
56 #include <sys/lock.h>
57 #include <sys/resident.h>
58 
59 #include <vm/vm.h>
60 #include <vm/vm_param.h>
61 #include <vm/pmap.h>
62 #include <vm/vm_map.h>
63 #include <vm/vm_kern.h>
64 #include <vm/vm_extern.h>
65 
66 #include <sys/sysref2.h>
67 #include <sys/mplock2.h>
68 
69 static int exec_res_id = 0;
70 
71 static TAILQ_HEAD(,vmresident) exec_res_list;
72 
73 static MALLOC_DEFINE(M_EXEC_RES, "vmresident", "resident execs");
74 
75 /* lockmgr lock for protecting the exec_res_list */
76 static struct lock exec_list_lock;
77 
78 static void
79 vm_resident_init(void *__dummy)
80 {
81 	lockinit(&exec_list_lock, "vmres", 0, 0);
82 	TAILQ_INIT(&exec_res_list);
83 }
84 SYSINIT(vmres, SI_BOOT1_LOCK, SI_ORDER_ANY, vm_resident_init, 0);
85 
86 static int
87 fill_xresident(struct vmresident *vr, struct xresident *in, struct thread *td)
88 {
89 	struct stat st;
90 	struct vnode *vrtmp;
91 	int error = 0;
92 
93 	vrtmp = vr->vr_vnode;
94 
95 	in->res_entry_addr = vr->vr_entry_addr;
96 	in->res_id = vr->vr_id;
97 	if (vrtmp) {
98 		char *freepath, *fullpath;
99 		error = vn_fullpath(td->td_proc, vrtmp, &fullpath, &freepath, 0);
100 		if (error != 0) {
101 			/* could not retrieve cached path, return zero'ed string */
102 			bzero(in->res_file, MAXPATHLEN);
103 			error = 0;
104 		} else {
105 			strlcpy(in->res_file, fullpath, sizeof(in->res_file));
106 			kfree(freepath, M_TEMP);
107 		}
108 
109 		/* indicate that we are using the vnode */
110 		error = vget(vrtmp, LK_EXCLUSIVE);
111 		if (error)
112 			goto done;
113 
114 		/* retrieve underlying stat information and release vnode */
115 		error = vn_stat(vrtmp, &st, td->td_ucred);
116 		vput(vrtmp);
117 		if (error)
118 			goto done;
119 
120 		in->res_stat = st;
121 	}
122 
123 done:
124 	if (error)
125 		kprintf("fill_xresident, error = %d\n", error);
126 	return (error);
127 }
128 
129 static int
130 sysctl_vm_resident(SYSCTL_HANDLER_ARGS)
131 {
132 	struct vmresident *vmres;
133 	struct thread *td;
134 	int error;
135 	int count;
136 
137 	/* only super-user should call this sysctl */
138 	td = req->td;
139 	if ((priv_check(td, PRIV_VM_RESIDENT)) != 0)
140 		return EPERM;
141 
142 	error = count = 0;
143 
144 	if (exec_res_id == 0)
145 	    return error;
146 
147 	/* client queried for number of resident binaries */
148 	if (!req->oldptr)
149 	    return SYSCTL_OUT(req, 0, exec_res_id);
150 
151 	lockmgr(&exec_list_lock, LK_SHARED);
152 
153 	TAILQ_FOREACH(vmres, &exec_res_list, vr_link) {
154 		struct xresident xres;
155 		error = fill_xresident(vmres, &xres, td);
156 		if (error != 0)
157 			break;
158 
159 		error = SYSCTL_OUT(req, (void *)&xres,
160 				sizeof(struct xresident));
161 		if (error != 0)
162 			break;
163 	}
164 	lockmgr(&exec_list_lock, LK_RELEASE);
165 
166 	return (error);
167 }
168 SYSCTL_PROC(_vm, OID_AUTO, resident, CTLTYPE_OPAQUE|CTLFLAG_RD, 0, 0,
169   sysctl_vm_resident, "S,xresident", "resident executables (sys/resident.h)");
170 
171 int
172 exec_resident_imgact(struct image_params *imgp)
173 {
174 	struct vmresident *vmres;
175 
176 	/*
177 	 * resident image activator
178 	 */
179 	lockmgr(&exec_list_lock, LK_SHARED);
180 	if ((vmres = imgp->vp->v_resident) == NULL) {
181 	    lockmgr(&exec_list_lock, LK_RELEASE);
182 	    return(-1);
183 	}
184 	atomic_add_int(&vmres->vr_refs, 1);
185 	lockmgr(&exec_list_lock, LK_RELEASE);
186 
187 	/*
188 	 * We want to exec the new vmspace without holding the lock to
189 	 * improve concurrency.
190 	 */
191 	exec_new_vmspace(imgp, vmres->vr_vmspace);
192 	imgp->resident = 1;
193 	imgp->interpreted = 0;
194 	imgp->proc->p_sysent = vmres->vr_sysent;
195 	imgp->entry_addr = vmres->vr_entry_addr;
196 	atomic_subtract_int(&vmres->vr_refs, 1);
197 
198 	return(0);
199 }
200 
201 /*
202  * exec_sys_register(entry)
203  *
204  * Register ourselves for resident execution.  Only root (i.e. a process with
205  * PRIV_VM_RESIDENT credentials) can do this.  This
206  * will snapshot the vmspace and cause future exec's of the specified binary
207  * to use the snapshot directly rather then load & relocate a new copy.
208  *
209  * MPALMOSTSAFE
210  */
211 int
212 sys_exec_sys_register(struct exec_sys_register_args *uap)
213 {
214     struct thread *td = curthread;
215     struct vmresident *vmres;
216     struct vnode *vp;
217     struct proc *p;
218     int error;
219 
220     p = td->td_proc;
221     error = priv_check_cred(td->td_ucred, PRIV_VM_RESIDENT, 0);
222     if (error)
223 	return(error);
224 
225     if ((vp = p->p_textvp) == NULL)
226 	return(ENOENT);
227 
228     lockmgr(&exec_list_lock, LK_EXCLUSIVE);
229 
230     if (vp->v_resident) {
231 	lockmgr(&exec_list_lock, LK_RELEASE);
232 	return(EEXIST);
233     }
234 
235     vhold(vp);
236     vmres = kmalloc(sizeof(*vmres), M_EXEC_RES, M_WAITOK | M_ZERO);
237     vmres->vr_vnode = vp;
238     vmres->vr_sysent = p->p_sysent;
239     vmres->vr_id = ++exec_res_id;
240     vmres->vr_entry_addr = (intptr_t)uap->entry;
241     vmres->vr_vmspace = vmspace_fork(p->p_vmspace); /* XXX order */
242     pmap_pinit2(vmspace_pmap(vmres->vr_vmspace));
243     vp->v_resident = vmres;
244 
245     TAILQ_INSERT_TAIL(&exec_res_list, vmres, vr_link);
246     lockmgr(&exec_list_lock, LK_RELEASE);
247 
248     return(0);
249 }
250 
251 /*
252  * exec_sys_unregister(id)
253  *
254  *	Unregister the specified id.  If an id of -1 is used unregister
255  *	the registration associated with the current process.  An id of -2
256  *	unregisters everything.
257  *
258  * MPALMOSTSAFE
259  */
260 int
261 sys_exec_sys_unregister(struct exec_sys_unregister_args *uap)
262 {
263     struct thread *td = curthread;
264     struct vmresident *vmres;
265     struct proc *p;
266     int error;
267     int id;
268     int count;
269 
270     p = td->td_proc;
271     error = priv_check_cred(td->td_ucred, PRIV_VM_RESIDENT, 0);
272     if (error)
273 	return(error);
274 
275     /*
276      * If id is -1, unregister ourselves
277      */
278     lockmgr(&exec_list_lock, LK_EXCLUSIVE);
279 
280     if ((id = uap->id) == -1 && p->p_textvp && p->p_textvp->v_resident)
281 	id = p->p_textvp->v_resident->vr_id;
282 
283     /*
284      * Look for the registration
285      */
286     error = ENOENT;
287     count = 0;
288 
289 restart:
290     TAILQ_FOREACH(vmres, &exec_res_list, vr_link) {
291 	if (id == -2 || vmres->vr_id == id) {
292 	    /*
293 	     * Check race against exec
294 	     */
295 	    if (vmres->vr_refs) {
296 		lockmgr(&exec_list_lock, LK_RELEASE);
297 		tsleep(vmres, 0, "vmres", 1);
298 		lockmgr(&exec_list_lock, LK_EXCLUSIVE);
299 		goto restart;
300 	    }
301 
302 	    /*
303 	     * Remove it
304 	     */
305 	    TAILQ_REMOVE(&exec_res_list, vmres, vr_link);
306 	    if (vmres->vr_vnode) {
307 		vmres->vr_vnode->v_resident = NULL;
308 		vdrop(vmres->vr_vnode);
309 		vmres->vr_vnode = NULL;
310 	    }
311 	    if (vmres->vr_vmspace) {
312 		sysref_put(&vmres->vr_vmspace->vm_sysref);
313 		vmres->vr_vmspace = NULL;
314 	    }
315 	    kfree(vmres, M_EXEC_RES);
316 	    exec_res_id--;
317 	    error = 0;
318 	    ++count;
319 	    goto restart;
320 	}
321     }
322     lockmgr(&exec_list_lock, LK_RELEASE);
323 
324     if (error == 0)
325 	uap->sysmsg_result = count;
326     return(error);
327 }
328 
329