xref: /freebsd/sys/kern/kern_module.c (revision a1a4f1a0d87b594d3f17a97dc0127eec1417e6f6)
1 /*-
2  * Copyright (c) 1997 Doug Rabson
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #include <sys/param.h>
30 #include <sys/kernel.h>
31 #include <sys/systm.h>
32 #include <sys/eventhandler.h>
33 #include <sys/malloc.h>
34 #include <sys/sysproto.h>
35 #include <sys/sysent.h>
36 #include <sys/module.h>
37 #include <sys/linker.h>
38 #include <sys/proc.h>
39 
40 #define M_MODULE	M_TEMP		/* XXX */
41 
42 typedef TAILQ_HEAD(, module) modulelist_t;
43 struct module {
44     TAILQ_ENTRY(module)	link;		/* chain together all modules */
45     TAILQ_ENTRY(module)	flink;		/* all modules in a file */
46     struct linker_file*	file;		/* file which contains this module */
47     int			refs;		/* reference count */
48     int			id;		/* unique id number */
49     char		*name;		/* module name */
50     modeventhand_t	handler;	/* event handler */
51     void		*arg;		/* argument for handler */
52     modspecific_t	data;		/* module specific data */
53 };
54 
55 #define MOD_EVENT(mod, type) (mod)->handler((mod), (type), (mod)->arg)
56 
57 static modulelist_t modules;
58 static int nextid = 1;
59 
60 static void module_shutdown(void*, int);
61 
62 static void
63 module_init(void* arg)
64 {
65     TAILQ_INIT(&modules);
66     EVENTHANDLER_REGISTER(shutdown_post_sync, module_shutdown, NULL,
67 			  SHUTDOWN_PRI_DEFAULT);
68 }
69 
70 SYSINIT(module, SI_SUB_KLD, SI_ORDER_FIRST, module_init, 0);
71 
72 static void
73 module_shutdown(void* arg1, int arg2)
74 {
75     module_t mod;
76 
77     for (mod = TAILQ_FIRST(&modules); mod; mod = TAILQ_NEXT(mod, link))
78 	MOD_EVENT(mod, MOD_SHUTDOWN);
79 }
80 
81 void
82 module_register_init(const void *arg)
83 {
84     const moduledata_t* data = (const moduledata_t*) arg;
85     int error;
86     module_t mod;
87 
88     mod = module_lookupbyname(data->name);
89     if (mod == NULL) {
90 #if 0
91 	panic("module_register_init: module named %s not found\n", data->name);
92 #else
93 	/* temporary kludge until kernel `file' attachment registers modules */
94 	error = module_register(data, linker_kernel_file);
95 	if (error)
96 	    panic("module_register_init: register of module failed! %d", error);
97 	mod = module_lookupbyname(data->name);
98 	if (mod == NULL)
99 	    panic("module_register_init: module STILL not found!");
100 #endif
101     }
102     error = MOD_EVENT(mod, MOD_LOAD);
103     if (error) {
104 	MOD_EVENT(mod, MOD_UNLOAD);
105 	module_release(mod);
106 	printf("module_register_init: MOD_LOAD (%s, %lx, %p) error %d\n",
107 	       data->name, (u_long)(uintfptr_t)data->evhand, data->priv, error);
108     }
109 }
110 
111 int
112 module_register(const moduledata_t *data, linker_file_t container)
113 {
114     size_t namelen;
115     module_t newmod;
116 
117     newmod = module_lookupbyname(data->name);
118     if (newmod != NULL) {
119 	printf("module_register: module %s already exists!\n", data->name);
120 	return EEXIST;
121     }
122     namelen = strlen(data->name) + 1;
123     newmod = (module_t) malloc(sizeof(struct module) + namelen,
124 			       M_MODULE, M_WAITOK);
125     if (newmod == 0)
126 	return ENOMEM;
127 
128     newmod->refs = 1;
129     newmod->id = nextid++;
130     newmod->name = (char *) (newmod + 1);
131     strcpy(newmod->name, data->name);
132     newmod->handler = data->evhand;
133     newmod->arg = data->priv;
134     bzero(&newmod->data, sizeof(newmod->data));
135     TAILQ_INSERT_TAIL(&modules, newmod, link);
136 
137     if (container == NULL)
138 	container = linker_current_file;
139     if (container)
140 	TAILQ_INSERT_TAIL(&container->modules, newmod, flink);
141     newmod->file = container;
142 
143     return 0;
144 }
145 
146 void
147 module_reference(module_t mod)
148 {
149     MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
150 
151     mod->refs++;
152 }
153 
154 void
155 module_release(module_t mod)
156 {
157     if (mod->refs <= 0)
158 	panic("module_release: bad reference count");
159 
160     MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
161 
162     mod->refs--;
163     if (mod->refs == 0) {
164 	TAILQ_REMOVE(&modules, mod, link);
165 	if (mod->file) {
166 	    TAILQ_REMOVE(&mod->file->modules, mod, flink);
167 	}
168 	free(mod, M_MODULE);
169     }
170 }
171 
172 module_t
173 module_lookupbyname(const char* name)
174 {
175     module_t mod;
176 
177     for (mod = TAILQ_FIRST(&modules); mod; mod = TAILQ_NEXT(mod, link)) {
178 	if (!strcmp(mod->name, name))
179 	    return mod;
180     }
181 
182     return 0;
183 }
184 
185 module_t
186 module_lookupbyid(int modid)
187 {
188     module_t mod;
189 
190     for (mod = TAILQ_FIRST(&modules); mod; mod = TAILQ_NEXT(mod, link)) {
191 	if (mod->id == modid)
192 	    return mod;
193     }
194 
195     return 0;
196 }
197 
198 int
199 module_unload(module_t mod)
200 {
201     return MOD_EVENT(mod, MOD_UNLOAD);
202 }
203 
204 int
205 module_getid(module_t mod)
206 {
207     return mod->id;
208 }
209 
210 module_t
211 module_getfnext(module_t mod)
212 {
213     return TAILQ_NEXT(mod, flink);
214 }
215 
216 void
217 module_setspecific(module_t mod, modspecific_t *datap)
218 {
219     mod->data = *datap;
220 }
221 
222 /*
223  * Syscalls.
224  */
225 int
226 modnext(struct proc* p, struct modnext_args* uap)
227 {
228     module_t mod;
229 
230     p->p_retval[0] = -1;
231     if (SCARG(uap, modid) == 0) {
232 	mod = TAILQ_FIRST(&modules);
233 	if (mod) {
234 	    p->p_retval[0] = mod->id;
235 	    return 0;
236 	} else
237 	    return ENOENT;
238     }
239 
240     mod = module_lookupbyid(SCARG(uap, modid));
241     if (!mod)
242 	return ENOENT;
243 
244     if (TAILQ_NEXT(mod, link))
245 	p->p_retval[0] = TAILQ_NEXT(mod, link)->id;
246     else
247 	p->p_retval[0] = 0;
248     return 0;
249 }
250 
251 int
252 modfnext(struct proc* p, struct modfnext_args* uap)
253 {
254     module_t mod;
255 
256     p->p_retval[0] = -1;
257 
258     mod = module_lookupbyid(SCARG(uap, modid));
259     if (!mod)
260 	return ENOENT;
261 
262     if (TAILQ_NEXT(mod, flink))
263 	p->p_retval[0] = TAILQ_NEXT(mod, flink)->id;
264     else
265 	p->p_retval[0] = 0;
266     return 0;
267 }
268 
269 struct module_stat_v1 {
270     int		version;	/* set to sizeof(struct module_stat) */
271     char	name[MAXMODNAME];
272     int		refs;
273     int		id;
274 };
275 
276 int
277 modstat(struct proc* p, struct modstat_args* uap)
278 {
279     module_t mod;
280     int error = 0;
281     int namelen;
282     int version;
283     struct module_stat* stat;
284 
285     mod = module_lookupbyid(SCARG(uap, modid));
286     if (!mod)
287 	return ENOENT;
288 
289     stat = SCARG(uap, stat);
290 
291     /*
292      * Check the version of the user's structure.
293      */
294     if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
295 	goto out;
296     if (version != sizeof(struct module_stat_v1)
297 	&& version != sizeof(struct module_stat)) {
298 	error = EINVAL;
299 	goto out;
300     }
301 
302     namelen = strlen(mod->name) + 1;
303     if (namelen > MAXMODNAME)
304 	namelen = MAXMODNAME;
305     if ((error = copyout(mod->name, &stat->name[0], namelen)) != 0)
306 	goto out;
307 
308     if ((error = copyout(&mod->refs, &stat->refs, sizeof(int))) != 0)
309 	goto out;
310     if ((error = copyout(&mod->id, &stat->id, sizeof(int))) != 0)
311 	goto out;
312 
313     /*
314      * >v1 stat includes module data.
315      */
316     if (version == sizeof(struct module_stat)) {
317 	if ((error = copyout(&mod->data, &stat->data, sizeof(mod->data))) != 0)
318 	    goto out;
319     }
320 
321     p->p_retval[0] = 0;
322 
323 out:
324     return error;
325 }
326 
327 int
328 modfind(struct proc* p, struct modfind_args* uap)
329 {
330     int error = 0;
331     char name[MAXMODNAME];
332     module_t mod;
333 
334     if ((error = copyinstr(SCARG(uap, name), name, sizeof name, 0)) != 0)
335 	goto out;
336 
337     mod = module_lookupbyname(name);
338     if (!mod)
339 	error = ENOENT;
340     else
341 	p->p_retval[0] = mod->id;
342 
343 out:
344     return error;
345 }
346