xref: /freebsd/sys/sys/sysent.h (revision f976241773df2260e6170317080761d1c5814fe5)
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  * $FreeBSD$
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 	int		sv_errsize;	/* size of errno translation table */
99 	const int 	*sv_errtbl;	/* errno translation table */
100 	int		(*sv_transtrap)(int, int);
101 					/* translate trap-to-signal mapping */
102 	int		(*sv_fixup)(uintptr_t *, struct image_params *);
103 					/* stack fixup function */
104 	void		(*sv_sendsig)(void (*)(int), struct ksiginfo *, struct __sigset *);
105 			    		/* send signal */
106 	char 		*sv_sigcode;	/* start of sigtramp code */
107 	int 		*sv_szsigcode;	/* size of sigtramp code */
108 	char		*sv_name;	/* name of binary type */
109 	int		(*sv_coredump)(struct thread *, struct vnode *, off_t, int);
110 					/* function to dump core, or NULL */
111 	int		(*sv_imgact_try)(struct image_params *);
112 	void		(*sv_stackgap)(struct image_params *, uintptr_t *);
113 	int		(*sv_copyout_auxargs)(struct image_params *,
114 			    uintptr_t);
115 	int		sv_minsigstksz;	/* minimum signal stack size */
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 	int		(*sv_copyout_strings)(struct image_params *,
122 			    uintptr_t *);
123 	void		(*sv_setregs)(struct thread *, struct image_params *,
124 			    uintptr_t);
125 	void		(*sv_fixlimit)(struct rlimit *, int);
126 	u_long		*sv_maxssiz;
127 	u_int		sv_flags;
128 	void		(*sv_set_syscall_retval)(struct thread *, int);
129 	int		(*sv_fetch_syscall_args)(struct thread *);
130 	const char	**sv_syscallnames;
131 	vm_offset_t	sv_timekeep_base;
132 	vm_offset_t	sv_shared_page_base;
133 	vm_offset_t	sv_shared_page_len;
134 	vm_offset_t	sv_sigcode_base;
135 	void		*sv_shared_page_obj;
136 	void		(*sv_schedtail)(struct thread *);
137 	void		(*sv_thread_detach)(struct thread *);
138 	int		(*sv_trap)(struct thread *);
139 	u_long		*sv_hwcap;	/* Value passed in AT_HWCAP. */
140 	u_long		*sv_hwcap2;	/* Value passed in AT_HWCAP2. */
141 };
142 
143 #define	SV_ILP32	0x000100	/* 32-bit executable. */
144 #define	SV_LP64		0x000200	/* 64-bit executable. */
145 #define	SV_IA32		0x004000	/* Intel 32-bit executable. */
146 #define	SV_AOUT		0x008000	/* a.out executable. */
147 #define	SV_SHP		0x010000	/* Shared page. */
148 #define	SV_CAPSICUM	0x020000	/* Force cap_enter() on startup. */
149 #define	SV_TIMEKEEP	0x040000	/* Shared page timehands. */
150 #define	SV_ASLR		0x080000	/* ASLR allowed. */
151 
152 #define	SV_ABI_MASK	0xff
153 #define	SV_ABI_ERRNO(p, e)	((p)->p_sysent->sv_errsize <= 0 ? e :	\
154 	((e) >= (p)->p_sysent->sv_errsize ? -1 : (p)->p_sysent->sv_errtbl[e]))
155 #define	SV_PROC_FLAG(p, x)	((p)->p_sysent->sv_flags & (x))
156 #define	SV_PROC_ABI(p)		((p)->p_sysent->sv_flags & SV_ABI_MASK)
157 #define	SV_CURPROC_FLAG(x)	SV_PROC_FLAG(curproc, x)
158 #define	SV_CURPROC_ABI()	SV_PROC_ABI(curproc)
159 /* same as ELFOSABI_XXX, to prevent header pollution */
160 #define	SV_ABI_LINUX	3
161 #define	SV_ABI_FREEBSD 	9
162 #define	SV_ABI_CLOUDABI	17
163 #define	SV_ABI_UNDEF	255
164 
165 #ifdef _KERNEL
166 extern struct sysentvec aout_sysvec;
167 extern struct sysent sysent[];
168 extern const char *syscallnames[];
169 
170 #define	NO_SYSCALL (-1)
171 
172 struct module;
173 
174 struct syscall_module_data {
175 	int	(*chainevh)(struct module *, int, void *); /* next handler */
176 	void	*chainarg;		/* arg for next event handler */
177 	int	*offset;		/* offset into sysent */
178 	struct sysent *new_sysent;	/* new sysent */
179 	struct sysent old_sysent;	/* old sysent */
180 	int	flags;			/* flags for syscall_register */
181 };
182 
183 /* separate initialization vector so it can be used in a substructure */
184 #define SYSENT_INIT_VALS(_syscallname) {			\
185 	.sy_narg = (sizeof(struct _syscallname ## _args )	\
186 	    / sizeof(register_t)),				\
187 	.sy_call = (sy_call_t *)&sys_##_syscallname,		\
188 	.sy_auevent = SYS_AUE_##_syscallname,			\
189 	.sy_systrace_args_func = NULL,				\
190 	.sy_entry = 0,						\
191 	.sy_return = 0,						\
192 	.sy_flags = 0,						\
193 	.sy_thrcnt = 0						\
194 }
195 
196 #define	MAKE_SYSENT(syscallname)				\
197 static struct sysent syscallname##_sysent = SYSENT_INIT_VALS(syscallname);
198 
199 #define	MAKE_SYSENT_COMPAT(syscallname)				\
200 static struct sysent syscallname##_sysent = {			\
201 	(sizeof(struct syscallname ## _args )			\
202 	    / sizeof(register_t)),				\
203 	(sy_call_t *)& syscallname,				\
204 	SYS_AUE_##syscallname					\
205 }
206 
207 #define SYSCALL_MODULE(name, offset, new_sysent, evh, arg)	\
208 static struct syscall_module_data name##_syscall_mod = {	\
209 	evh, arg, offset, new_sysent, { 0, NULL, AUE_NULL }	\
210 };								\
211 								\
212 static moduledata_t name##_mod = {				\
213 	"sys/" #name,						\
214 	syscall_module_handler,					\
215 	&name##_syscall_mod					\
216 };								\
217 DECLARE_MODULE(name, name##_mod, SI_SUB_SYSCALLS, SI_ORDER_MIDDLE)
218 
219 #define	SYSCALL_MODULE_HELPER(syscallname)			\
220 static int syscallname##_syscall = SYS_##syscallname;		\
221 MAKE_SYSENT(syscallname);					\
222 SYSCALL_MODULE(syscallname,					\
223     & syscallname##_syscall, & syscallname##_sysent,		\
224     NULL, NULL)
225 
226 #define	SYSCALL_MODULE_PRESENT(syscallname)				\
227 	(sysent[SYS_##syscallname].sy_call != (sy_call_t *)lkmnosys &&	\
228 	sysent[SYS_##syscallname].sy_call != (sy_call_t *)lkmressys)
229 
230 /*
231  * Syscall registration helpers with resource allocation handling.
232  */
233 struct syscall_helper_data {
234 	struct sysent new_sysent;
235 	struct sysent old_sysent;
236 	int syscall_no;
237 	int registered;
238 };
239 #define SYSCALL_INIT_HELPER_F(syscallname, flags) {		\
240     .new_sysent = {						\
241 	.sy_narg = (sizeof(struct syscallname ## _args )	\
242 	    / sizeof(register_t)),				\
243 	.sy_call = (sy_call_t *)& sys_ ## syscallname,		\
244 	.sy_auevent = SYS_AUE_##syscallname,			\
245 	.sy_flags = (flags)					\
246     },								\
247     .syscall_no = SYS_##syscallname				\
248 }
249 #define SYSCALL_INIT_HELPER_COMPAT_F(syscallname, flags) {	\
250     .new_sysent = {						\
251 	.sy_narg = (sizeof(struct syscallname ## _args )	\
252 	    / sizeof(register_t)),				\
253 	.sy_call = (sy_call_t *)& syscallname,			\
254 	.sy_auevent = SYS_AUE_##syscallname,			\
255 	.sy_flags = (flags)					\
256     },								\
257     .syscall_no = SYS_##syscallname				\
258 }
259 #define SYSCALL_INIT_HELPER(syscallname)			\
260     SYSCALL_INIT_HELPER_F(syscallname, 0)
261 #define SYSCALL_INIT_HELPER_COMPAT(syscallname)			\
262     SYSCALL_INIT_HELPER_COMPAT_F(syscallname, 0)
263 #define SYSCALL_INIT_LAST {					\
264     .syscall_no = NO_SYSCALL					\
265 }
266 
267 int	syscall_module_handler(struct module *mod, int what, void *arg);
268 int	syscall_helper_register(struct syscall_helper_data *sd, int flags);
269 int	syscall_helper_unregister(struct syscall_helper_data *sd);
270 /* Implementation, exposed for COMPAT code */
271 int	kern_syscall_register(struct sysent *sysents, int *offset,
272 	    struct sysent *new_sysent, struct sysent *old_sysent, int flags);
273 int	kern_syscall_deregister(struct sysent *sysents, int offset,
274 	    const struct sysent *old_sysent);
275 int	kern_syscall_module_handler(struct sysent *sysents,
276 	    struct module *mod, int what, void *arg);
277 int	kern_syscall_helper_register(struct sysent *sysents,
278 	    struct syscall_helper_data *sd, int flags);
279 int	kern_syscall_helper_unregister(struct sysent *sysents,
280 	    struct syscall_helper_data *sd);
281 
282 struct proc;
283 const char *syscallname(struct proc *p, u_int code);
284 
285 /* Special purpose system call functions. */
286 struct nosys_args;
287 
288 int	lkmnosys(struct thread *, struct nosys_args *);
289 int	lkmressys(struct thread *, struct nosys_args *);
290 
291 int	_syscall_thread_enter(struct thread *td, struct sysent *se);
292 void	_syscall_thread_exit(struct thread *td, struct sysent *se);
293 
294 static inline int
295 syscall_thread_enter(struct thread *td, struct sysent *se)
296 {
297 
298 	if (__predict_true((se->sy_thrcnt & SY_THR_STATIC) != 0))
299 		return (0);
300 	return (_syscall_thread_enter(td, se));
301 }
302 
303 static inline void
304 syscall_thread_exit(struct thread *td, struct sysent *se)
305 {
306 
307 	if (__predict_true((se->sy_thrcnt & SY_THR_STATIC) != 0))
308 		return;
309 	_syscall_thread_exit(td, se);
310 }
311 
312 int shared_page_alloc(int size, int align);
313 int shared_page_fill(int size, int align, const void *data);
314 void shared_page_write(int base, int size, const void *data);
315 void exec_sysvec_init(void *param);
316 void exec_inittk(void);
317 
318 #define INIT_SYSENTVEC(name, sv)					\
319     SYSINIT(name, SI_SUB_EXEC, SI_ORDER_ANY,				\
320 	(sysinit_cfunc_t)exec_sysvec_init, sv);
321 
322 #endif /* _KERNEL */
323 
324 #endif /* !_SYS_SYSENT_H_ */
325