1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1988, 1991 The Regents of the University of California.
5 * All rights reserved.
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 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * $FreeBSD: stable/12/sys/sys/sysent.h 351024 2019-08-14 09:56:58Z kib $
32 */
33
34 #ifndef _SYS_SYSENT_H_
35 #define _SYS_SYSENT_H_
36
37 #include <bsm/audit.h>
38
39 struct rlimit;
40 struct sysent;
41 struct thread;
42 struct ksiginfo;
43 struct syscall_args;
44
45 enum systrace_probe_t {
46 SYSTRACE_ENTRY,
47 SYSTRACE_RETURN,
48 };
49
50 typedef int sy_call_t(struct thread *, void *);
51
52 typedef void (*systrace_probe_func_t)(struct syscall_args *,
53 enum systrace_probe_t, int);
54 typedef void (*systrace_args_func_t)(int, void *, uint64_t *, int *);
55
56 #ifdef _KERNEL
57 extern bool systrace_enabled;
58 #endif
59 extern systrace_probe_func_t systrace_probe_func;
60
61 struct sysent { /* system call table */
62 int sy_narg; /* number of arguments */
63 sy_call_t *sy_call; /* implementing function */
64 au_event_t sy_auevent; /* audit event associated with syscall */
65 systrace_args_func_t sy_systrace_args_func;
66 /* optional argument conversion function. */
67 u_int32_t sy_entry; /* DTrace entry ID for systrace. */
68 u_int32_t sy_return; /* DTrace return ID for systrace. */
69 u_int32_t sy_flags; /* General flags for system calls. */
70 u_int32_t sy_thrcnt;
71 };
72
73 /*
74 * A system call is permitted in capability mode.
75 */
76 #define SYF_CAPENABLED 0x00000001
77
78 #define SY_THR_FLAGMASK 0x7
79 #define SY_THR_STATIC 0x1
80 #define SY_THR_DRAINING 0x2
81 #define SY_THR_ABSENT 0x4
82 #define SY_THR_INCR 0x8
83
84 #ifdef KLD_MODULE
85 #define SY_THR_STATIC_KLD 0
86 #else
87 #define SY_THR_STATIC_KLD SY_THR_STATIC
88 #endif
89
90 struct image_params;
91 struct __sigset;
92 struct trapframe;
93 struct vnode;
94
95 struct sysentvec {
96 int sv_size; /* number of entries */
97 struct sysent *sv_table; /* pointer to sysent */
98 u_int sv_mask; /* optional mask to index */
99 int sv_errsize; /* size of errno translation table */
100 const int *sv_errtbl; /* errno translation table */
101 int (*sv_transtrap)(int, int);
102 /* translate trap-to-signal mapping */
103 int (*sv_fixup)(register_t **, struct image_params *);
104 /* stack fixup function */
105 void (*sv_sendsig)(void (*)(int), struct ksiginfo *, struct __sigset *);
106 /* send signal */
107 char *sv_sigcode; /* start of sigtramp code */
108 int *sv_szsigcode; /* size of sigtramp code */
109 char *sv_name; /* name of binary type */
110 int (*sv_coredump)(struct thread *, struct vnode *, off_t, int);
111 /* function to dump core, or NULL */
112 int (*sv_imgact_try)(struct image_params *);
113 void (*sv_stackgap)(struct image_params *, u_long *);
114 int sv_minsigstksz; /* minimum signal stack size */
115 int sv_pagesize; /* spare / no longer used */
116 vm_offset_t sv_minuser; /* VM_MIN_ADDRESS */
117 vm_offset_t sv_maxuser; /* VM_MAXUSER_ADDRESS */
118 vm_offset_t sv_usrstack; /* USRSTACK */
119 vm_offset_t sv_psstrings; /* PS_STRINGS */
120 int sv_stackprot; /* vm protection for stack */
121 register_t *(*sv_copyout_strings)(struct image_params *);
122 void (*sv_setregs)(struct thread *, struct image_params *,
123 u_long);
124 void (*sv_fixlimit)(struct rlimit *, int);
125 u_long *sv_maxssiz;
126 u_int sv_flags;
127 void (*sv_set_syscall_retval)(struct thread *, int);
128 int (*sv_fetch_syscall_args)(struct thread *);
129 const char **sv_syscallnames;
130 vm_offset_t sv_timekeep_base;
131 vm_offset_t sv_shared_page_base;
132 vm_offset_t sv_shared_page_len;
133 vm_offset_t sv_sigcode_base;
134 void *sv_shared_page_obj;
135 void (*sv_schedtail)(struct thread *);
136 void (*sv_thread_detach)(struct thread *);
137 int (*sv_trap)(struct thread *);
138 u_long *sv_hwcap; /* Value passed in AT_HWCAP. */
139 u_long *sv_hwcap2; /* Value passed in AT_HWCAP2. */
140 };
141
142 #define SV_ILP32 0x000100 /* 32-bit executable. */
143 #define SV_LP64 0x000200 /* 64-bit executable. */
144 #define SV_IA32 0x004000 /* Intel 32-bit executable. */
145 #define SV_AOUT 0x008000 /* a.out executable. */
146 #define SV_SHP 0x010000 /* Shared page. */
147 #define SV_CAPSICUM 0x020000 /* Force cap_enter() on startup. */
148 #define SV_TIMEKEEP 0x040000 /* Shared page timehands. */
149 #define SV_ASLR 0x080000 /* ASLR allowed. */
150
151 #define SV_ABI_MASK 0xff
152 #define SV_ABI_ERRNO(p, e) ((p)->p_sysent->sv_errsize <= 0 ? e : \
153 ((e) >= (p)->p_sysent->sv_errsize ? -1 : (p)->p_sysent->sv_errtbl[e]))
154 #define SV_PROC_FLAG(p, x) ((p)->p_sysent->sv_flags & (x))
155 #define SV_PROC_ABI(p) ((p)->p_sysent->sv_flags & SV_ABI_MASK)
156 #define SV_CURPROC_FLAG(x) SV_PROC_FLAG(curproc, x)
157 #define SV_CURPROC_ABI() SV_PROC_ABI(curproc)
158 /* same as ELFOSABI_XXX, to prevent header pollution */
159 #define SV_ABI_LINUX 3
160 #define SV_ABI_FREEBSD 9
161 #define SV_ABI_CLOUDABI 17
162 #define SV_ABI_UNDEF 255
163
164 #ifdef _KERNEL
165 extern struct sysentvec aout_sysvec;
166 extern struct sysent sysent[];
167 extern const char *syscallnames[];
168
169 #if defined(__amd64__)
170 extern int i386_read_exec;
171 #endif
172
173 #define NO_SYSCALL (-1)
174
175 struct module;
176
177 struct syscall_module_data {
178 int (*chainevh)(struct module *, int, void *); /* next handler */
179 void *chainarg; /* arg for next event handler */
180 int *offset; /* offset into sysent */
181 struct sysent *new_sysent; /* new sysent */
182 struct sysent old_sysent; /* old sysent */
183 int flags; /* flags for syscall_register */
184 };
185
186 /* separate initialization vector so it can be used in a substructure */
187 #define SYSENT_INIT_VALS(_syscallname) { \
188 .sy_narg = (sizeof(struct _syscallname ## _args ) \
189 / sizeof(register_t)), \
190 .sy_call = (sy_call_t *)&sys_##_syscallname, \
191 .sy_auevent = SYS_AUE_##_syscallname, \
192 .sy_systrace_args_func = NULL, \
193 .sy_entry = 0, \
194 .sy_return = 0, \
195 .sy_flags = 0, \
196 .sy_thrcnt = 0 \
197 }
198
199 #define MAKE_SYSENT(syscallname) \
200 static struct sysent syscallname##_sysent = SYSENT_INIT_VALS(syscallname);
201
202 #define MAKE_SYSENT_COMPAT(syscallname) \
203 static struct sysent syscallname##_sysent = { \
204 (sizeof(struct syscallname ## _args ) \
205 / sizeof(register_t)), \
206 (sy_call_t *)& syscallname, \
207 SYS_AUE_##syscallname \
208 }
209
210 #define SYSCALL_MODULE(name, offset, new_sysent, evh, arg) \
211 static struct syscall_module_data name##_syscall_mod = { \
212 evh, arg, offset, new_sysent, { 0, NULL, AUE_NULL } \
213 }; \
214 \
215 static moduledata_t name##_mod = { \
216 "sys/" #name, \
217 syscall_module_handler, \
218 &name##_syscall_mod \
219 }; \
220 DECLARE_MODULE(name, name##_mod, SI_SUB_SYSCALLS, SI_ORDER_MIDDLE)
221
222 #define SYSCALL_MODULE_HELPER(syscallname) \
223 static int syscallname##_syscall = SYS_##syscallname; \
224 MAKE_SYSENT(syscallname); \
225 SYSCALL_MODULE(syscallname, \
226 & syscallname##_syscall, & syscallname##_sysent, \
227 NULL, NULL)
228
229 #define SYSCALL_MODULE_PRESENT(syscallname) \
230 (sysent[SYS_##syscallname].sy_call != (sy_call_t *)lkmnosys && \
231 sysent[SYS_##syscallname].sy_call != (sy_call_t *)lkmressys)
232
233 /*
234 * Syscall registration helpers with resource allocation handling.
235 */
236 struct syscall_helper_data {
237 struct sysent new_sysent;
238 struct sysent old_sysent;
239 int syscall_no;
240 int registered;
241 };
242 #define SYSCALL_INIT_HELPER_F(syscallname, flags) { \
243 .new_sysent = { \
244 .sy_narg = (sizeof(struct syscallname ## _args ) \
245 / sizeof(register_t)), \
246 .sy_call = (sy_call_t *)& sys_ ## syscallname, \
247 .sy_auevent = SYS_AUE_##syscallname, \
248 .sy_flags = (flags) \
249 }, \
250 .syscall_no = SYS_##syscallname \
251 }
252 #define SYSCALL_INIT_HELPER_COMPAT_F(syscallname, flags) { \
253 .new_sysent = { \
254 .sy_narg = (sizeof(struct syscallname ## _args ) \
255 / sizeof(register_t)), \
256 .sy_call = (sy_call_t *)& syscallname, \
257 .sy_auevent = SYS_AUE_##syscallname, \
258 .sy_flags = (flags) \
259 }, \
260 .syscall_no = SYS_##syscallname \
261 }
262 #define SYSCALL_INIT_HELPER(syscallname) \
263 SYSCALL_INIT_HELPER_F(syscallname, 0)
264 #define SYSCALL_INIT_HELPER_COMPAT(syscallname) \
265 SYSCALL_INIT_HELPER_COMPAT_F(syscallname, 0)
266 #define SYSCALL_INIT_LAST { \
267 .syscall_no = NO_SYSCALL \
268 }
269
270 int syscall_module_handler(struct module *mod, int what, void *arg);
271 int syscall_helper_register(struct syscall_helper_data *sd, int flags);
272 int syscall_helper_unregister(struct syscall_helper_data *sd);
273 /* Implementation, exposed for COMPAT code */
274 int kern_syscall_register(struct sysent *sysents, int *offset,
275 struct sysent *new_sysent, struct sysent *old_sysent, int flags);
276 int kern_syscall_deregister(struct sysent *sysents, int offset,
277 const struct sysent *old_sysent);
278 int kern_syscall_module_handler(struct sysent *sysents,
279 struct module *mod, int what, void *arg);
280 int kern_syscall_helper_register(struct sysent *sysents,
281 struct syscall_helper_data *sd, int flags);
282 int kern_syscall_helper_unregister(struct sysent *sysents,
283 struct syscall_helper_data *sd);
284
285 struct proc;
286 const char *syscallname(struct proc *p, u_int code);
287
288 /* Special purpose system call functions. */
289 struct nosys_args;
290
291 int lkmnosys(struct thread *, struct nosys_args *);
292 int lkmressys(struct thread *, struct nosys_args *);
293
294 int _syscall_thread_enter(struct thread *td, struct sysent *se);
295 void _syscall_thread_exit(struct thread *td, struct sysent *se);
296
297 static inline int
syscall_thread_enter(struct thread * td,struct sysent * se)298 syscall_thread_enter(struct thread *td, struct sysent *se)
299 {
300
301 if (__predict_true((se->sy_thrcnt & SY_THR_STATIC) != 0))
302 return (0);
303 return (_syscall_thread_enter(td, se));
304 }
305
306 static inline void
syscall_thread_exit(struct thread * td,struct sysent * se)307 syscall_thread_exit(struct thread *td, struct sysent *se)
308 {
309
310 if (__predict_true((se->sy_thrcnt & SY_THR_STATIC) != 0))
311 return;
312 _syscall_thread_exit(td, se);
313 }
314
315 int shared_page_alloc(int size, int align);
316 int shared_page_fill(int size, int align, const void *data);
317 void shared_page_write(int base, int size, const void *data);
318 void exec_sysvec_init(void *param);
319 void exec_inittk(void);
320
321 #define INIT_SYSENTVEC(name, sv) \
322 SYSINIT(name, SI_SUB_EXEC, SI_ORDER_ANY, \
323 (sysinit_cfunc_t)exec_sysvec_init, sv);
324
325 #endif /* _KERNEL */
326
327 #endif /* !_SYS_SYSENT_H_ */
328