xref: /freebsd/sys/sys/sysent.h (revision 0333fad1b7e042eea0fe8348c6fde8ee55538d63)
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 systrace_probe_func_t	systrace_probe_func;
58 extern bool			systrace_enabled;
59 
60 #ifdef KDTRACE_HOOKS
61 #define	SYSTRACE_ENABLED()	(systrace_enabled)
62 #else
63 #define SYSTRACE_ENABLED()	(0)
64 #endif
65 #endif /* _KERNEL */
66 
67 struct sysent {			/* system call table */
68 	sy_call_t *sy_call;	/* implementing function */
69 	systrace_args_func_t sy_systrace_args_func;
70 				/* optional argument conversion function. */
71 	u_int8_t sy_narg;	/* number of arguments */
72 	u_int8_t sy_flags;	/* General flags for system calls. */
73 	au_event_t sy_auevent;	/* audit event associated with syscall */
74 	u_int32_t sy_entry;	/* DTrace entry ID for systrace. */
75 	u_int32_t sy_return;	/* DTrace return ID for systrace. */
76 	u_int32_t sy_thrcnt;
77 };
78 
79 /*
80  * A system call is permitted in capability mode.
81  */
82 #define	SYF_CAPENABLED	0x00000001
83 
84 #define	SY_THR_FLAGMASK	0x7
85 #define	SY_THR_STATIC	0x1
86 #define	SY_THR_DRAINING	0x2
87 #define	SY_THR_ABSENT	0x4
88 #define	SY_THR_INCR	0x8
89 
90 #ifdef KLD_MODULE
91 #define	SY_THR_STATIC_KLD	0
92 #else
93 #define	SY_THR_STATIC_KLD	SY_THR_STATIC
94 #endif
95 
96 struct image_params;
97 struct proc;
98 struct __sigset;
99 struct trapframe;
100 struct vnode;
101 
102 struct sysentvec {
103 	int		sv_size;	/* number of entries */
104 	struct sysent	*sv_table;	/* pointer to sysent */
105 	int		(*sv_transtrap)(int, int);
106 					/* translate trap-to-signal mapping */
107 	int		(*sv_fixup)(uintptr_t *, struct image_params *);
108 					/* stack fixup function */
109 	void		(*sv_sendsig)(void (*)(int), struct ksiginfo *, struct __sigset *);
110 			    		/* send signal */
111 	char 		*sv_sigcode;	/* start of sigtramp code */
112 	int 		*sv_szsigcode;	/* size of sigtramp code */
113 	char		*sv_name;	/* name of binary type */
114 	int		(*sv_coredump)(struct thread *, struct vnode *, off_t, int);
115 					/* function to dump core, or NULL */
116 	int		(*sv_imgact_try)(struct image_params *);
117 	void		(*sv_stackgap)(struct image_params *, uintptr_t *);
118 	int		(*sv_copyout_auxargs)(struct image_params *,
119 			    uintptr_t);
120 	int		sv_minsigstksz;	/* minimum signal stack size */
121 	vm_offset_t	sv_minuser;	/* VM_MIN_ADDRESS */
122 	vm_offset_t	sv_maxuser;	/* VM_MAXUSER_ADDRESS */
123 	vm_offset_t	sv_usrstack;	/* USRSTACK */
124 	vm_offset_t	sv_psstrings;	/* PS_STRINGS */
125 	int		sv_stackprot;	/* vm protection for stack */
126 	int		(*sv_copyout_strings)(struct image_params *,
127 			    uintptr_t *);
128 	void		(*sv_setregs)(struct thread *, struct image_params *,
129 			    uintptr_t);
130 	void		(*sv_fixlimit)(struct rlimit *, int);
131 	u_long		*sv_maxssiz;
132 	u_int		sv_flags;
133 	void		(*sv_set_syscall_retval)(struct thread *, int);
134 	int		(*sv_fetch_syscall_args)(struct thread *);
135 	const char	**sv_syscallnames;
136 	vm_offset_t	sv_timekeep_base;
137 	vm_offset_t	sv_shared_page_base;
138 	vm_offset_t	sv_shared_page_len;
139 	vm_offset_t	sv_sigcode_base;
140 	void		*sv_shared_page_obj;
141 	void		(*sv_schedtail)(struct thread *);
142 	void		(*sv_thread_detach)(struct thread *);
143 	int		(*sv_trap)(struct thread *);
144 	u_long		*sv_hwcap;	/* Value passed in AT_HWCAP. */
145 	u_long		*sv_hwcap2;	/* Value passed in AT_HWCAP2. */
146 	const char	*(*sv_machine_arch)(struct proc *);
147 	vm_offset_t	sv_fxrng_gen_base;
148 	void		(*sv_onexec)(struct proc *, struct image_params *);
149 	void		(*sv_onexit)(struct proc *);
150 	void		(*sv_ontdexit)(struct thread *td);
151 	int		(*sv_setid_allowed)(struct thread *td,
152 			    struct image_params *imgp);
153 };
154 
155 #define	SV_ILP32	0x000100	/* 32-bit executable. */
156 #define	SV_LP64		0x000200	/* 64-bit executable. */
157 #define	SV_IA32		0x004000	/* Intel 32-bit executable. */
158 #define	SV_AOUT		0x008000	/* a.out executable. */
159 #define	SV_SHP		0x010000	/* Shared page. */
160 #define	SV_CAPSICUM	0x020000	/* Force cap_enter() on startup. */
161 #define	SV_TIMEKEEP	0x040000	/* Shared page timehands. */
162 #define	SV_ASLR		0x080000	/* ASLR allowed. */
163 #define	SV_RNG_SEED_VER	0x100000	/* random(4) reseed generation. */
164 
165 #define	SV_ABI_MASK	0xff
166 #define	SV_PROC_FLAG(p, x)	((p)->p_sysent->sv_flags & (x))
167 #define	SV_PROC_ABI(p)		((p)->p_sysent->sv_flags & SV_ABI_MASK)
168 #define	SV_CURPROC_FLAG(x)	SV_PROC_FLAG(curproc, x)
169 #define	SV_CURPROC_ABI()	SV_PROC_ABI(curproc)
170 /* same as ELFOSABI_XXX, to prevent header pollution */
171 #define	SV_ABI_LINUX	3
172 #define	SV_ABI_FREEBSD 	9
173 #define	SV_ABI_CLOUDABI	17
174 #define	SV_ABI_UNDEF	255
175 
176 /* sv_coredump flags */
177 #define	SVC_PT_COREDUMP	0x00000001	/* dump requested by ptrace(2) */
178 #define	SVC_NOCOMPRESS	0x00000002	/* disable compression. */
179 #define	SVC_ALL		0x00000004	/* dump everything */
180 
181 #ifdef _KERNEL
182 extern struct sysentvec aout_sysvec;
183 extern struct sysent sysent[];
184 extern const char *syscallnames[];
185 
186 #define	NO_SYSCALL (-1)
187 
188 struct module;
189 
190 struct syscall_module_data {
191 	int	(*chainevh)(struct module *, int, void *); /* next handler */
192 	void	*chainarg;		/* arg for next event handler */
193 	int	*offset;		/* offset into sysent */
194 	struct sysent *new_sysent;	/* new sysent */
195 	struct sysent old_sysent;	/* old sysent */
196 	int	flags;			/* flags for syscall_register */
197 };
198 
199 /* separate initialization vector so it can be used in a substructure */
200 #define SYSENT_INIT_VALS(_syscallname) {			\
201 	.sy_narg = (sizeof(struct _syscallname ## _args )	\
202 	    / sizeof(register_t)),				\
203 	.sy_call = (sy_call_t *)&sys_##_syscallname,		\
204 	.sy_auevent = SYS_AUE_##_syscallname,			\
205 	.sy_systrace_args_func = NULL,				\
206 	.sy_entry = 0,						\
207 	.sy_return = 0,						\
208 	.sy_flags = 0,						\
209 	.sy_thrcnt = 0						\
210 }
211 
212 #define	MAKE_SYSENT(syscallname)				\
213 static struct sysent syscallname##_sysent = SYSENT_INIT_VALS(syscallname);
214 
215 #define	MAKE_SYSENT_COMPAT(syscallname)				\
216 static struct sysent syscallname##_sysent = {			\
217 	(sizeof(struct syscallname ## _args )			\
218 	    / sizeof(register_t)),				\
219 	(sy_call_t *)& syscallname,				\
220 	SYS_AUE_##syscallname					\
221 }
222 
223 #define SYSCALL_MODULE(name, offset, new_sysent, evh, arg)	\
224 static struct syscall_module_data name##_syscall_mod = {	\
225 	evh, arg, offset, new_sysent, { 0, NULL, AUE_NULL }	\
226 };								\
227 								\
228 static moduledata_t name##_mod = {				\
229 	"sys/" #name,						\
230 	syscall_module_handler,					\
231 	&name##_syscall_mod					\
232 };								\
233 DECLARE_MODULE(name, name##_mod, SI_SUB_SYSCALLS, SI_ORDER_MIDDLE)
234 
235 #define	SYSCALL_MODULE_HELPER(syscallname)			\
236 static int syscallname##_syscall = SYS_##syscallname;		\
237 MAKE_SYSENT(syscallname);					\
238 SYSCALL_MODULE(syscallname,					\
239     & syscallname##_syscall, & syscallname##_sysent,		\
240     NULL, NULL)
241 
242 #define	SYSCALL_MODULE_PRESENT(syscallname)				\
243 	(sysent[SYS_##syscallname].sy_call != (sy_call_t *)lkmnosys &&	\
244 	sysent[SYS_##syscallname].sy_call != (sy_call_t *)lkmressys)
245 
246 /*
247  * Syscall registration helpers with resource allocation handling.
248  */
249 struct syscall_helper_data {
250 	struct sysent new_sysent;
251 	struct sysent old_sysent;
252 	int syscall_no;
253 	int registered;
254 };
255 #define SYSCALL_INIT_HELPER_F(syscallname, flags) {		\
256     .new_sysent = {						\
257 	.sy_narg = (sizeof(struct syscallname ## _args )	\
258 	    / sizeof(register_t)),				\
259 	.sy_call = (sy_call_t *)& sys_ ## syscallname,		\
260 	.sy_auevent = SYS_AUE_##syscallname,			\
261 	.sy_flags = (flags)					\
262     },								\
263     .syscall_no = SYS_##syscallname				\
264 }
265 #define SYSCALL_INIT_HELPER_COMPAT_F(syscallname, flags) {	\
266     .new_sysent = {						\
267 	.sy_narg = (sizeof(struct syscallname ## _args )	\
268 	    / sizeof(register_t)),				\
269 	.sy_call = (sy_call_t *)& syscallname,			\
270 	.sy_auevent = SYS_AUE_##syscallname,			\
271 	.sy_flags = (flags)					\
272     },								\
273     .syscall_no = SYS_##syscallname				\
274 }
275 #define SYSCALL_INIT_HELPER(syscallname)			\
276     SYSCALL_INIT_HELPER_F(syscallname, 0)
277 #define SYSCALL_INIT_HELPER_COMPAT(syscallname)			\
278     SYSCALL_INIT_HELPER_COMPAT_F(syscallname, 0)
279 #define SYSCALL_INIT_LAST {					\
280     .syscall_no = NO_SYSCALL					\
281 }
282 
283 int	syscall_module_handler(struct module *mod, int what, void *arg);
284 int	syscall_helper_register(struct syscall_helper_data *sd, int flags);
285 int	syscall_helper_unregister(struct syscall_helper_data *sd);
286 /* Implementation, exposed for COMPAT code */
287 int	kern_syscall_register(struct sysent *sysents, int *offset,
288 	    struct sysent *new_sysent, struct sysent *old_sysent, int flags);
289 int	kern_syscall_deregister(struct sysent *sysents, int offset,
290 	    const struct sysent *old_sysent);
291 int	kern_syscall_module_handler(struct sysent *sysents,
292 	    struct module *mod, int what, void *arg);
293 int	kern_syscall_helper_register(struct sysent *sysents,
294 	    struct syscall_helper_data *sd, int flags);
295 int	kern_syscall_helper_unregister(struct sysent *sysents,
296 	    struct syscall_helper_data *sd);
297 
298 struct proc;
299 const char *syscallname(struct proc *p, u_int code);
300 
301 /* Special purpose system call functions. */
302 struct nosys_args;
303 
304 int	lkmnosys(struct thread *, struct nosys_args *);
305 int	lkmressys(struct thread *, struct nosys_args *);
306 
307 int	syscall_thread_enter(struct thread *td, struct sysent *se);
308 void	syscall_thread_exit(struct thread *td, struct sysent *se);
309 
310 int shared_page_alloc(int size, int align);
311 int shared_page_fill(int size, int align, const void *data);
312 void shared_page_write(int base, int size, const void *data);
313 void exec_sysvec_init(void *param);
314 void exec_sysvec_init_secondary(struct sysentvec *sv, struct sysentvec *sv2);
315 void exec_inittk(void);
316 
317 #define INIT_SYSENTVEC(name, sv)					\
318     SYSINIT(name, SI_SUB_EXEC, SI_ORDER_ANY,				\
319 	(sysinit_cfunc_t)exec_sysvec_init, sv);
320 
321 #endif /* _KERNEL */
322 
323 #endif /* !_SYS_SYSENT_H_ */
324