1 /* $NetBSD: syscall.c,v 1.27 2023/10/05 19:41:06 ad Exp $ */
2
3 /*-
4 * Copyright (c) 2007 Jared D. McNeill <jmcneill@invisible.ca>
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 *
16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: syscall.c,v 1.27 2023/10/05 19:41:06 ad Exp $");
31
32 #include <sys/types.h>
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/proc.h>
36 #include <sys/lwp.h>
37 #include <sys/sched.h>
38 #include <sys/ktrace.h>
39 #include <sys/syscall.h>
40 #include <sys/syscallvar.h>
41 #include <sys/syscallargs.h>
42
43 #include <sys/userret.h>
44 #include <machine/pcb.h>
45 #include <machine/thunk.h>
46 #include <machine/machdep.h>
47
48 void
md_child_return(struct lwp * l)49 md_child_return(struct lwp *l)
50 {
51 register_t rval[2];
52 struct pcb *pcb = lwp_getpcb(l);
53 ucontext_t *ucp = &pcb->pcb_userret_ucp;
54
55 /* return value zero */
56 rval[0] = 0;
57 rval[1] = 0;
58 md_syscall_set_returnargs(l, ucp, 0, rval);
59
60 aprint_debug("child return! lwp %p\n", l);
61 userret(l);
62 }
63
64 /*
65 * Process the tail end of a posix_spawn() for the child.
66 */
67 void
cpu_spawn_return(struct lwp * l)68 cpu_spawn_return(struct lwp *l)
69 {
70
71 userret(l);
72 }
73
74 extern const char *const syscallnames[];
75
76 static void syscall_args_print(lwp_t *l, int code, int nargs, int argsize,
77 register_t *args);
78 static void syscall_retvals_print(lwp_t *l, lwp_t *clwp,
79 int code, int nargs, register_t *args, int error, register_t *rval);
80
81
82 void
syscall(void)83 syscall(void)
84 {
85 lwp_t *l = curlwp;
86 const struct proc * const p = l->l_proc;
87 const struct sysent *callp;
88 struct pcb *pcb = lwp_getpcb(l);
89 ucontext_t *ucp = &pcb->pcb_userret_ucp;
90 register_t copyargs[2+SYS_MAXSYSARGS];
91 register_t *args;
92 register_t rval[2];
93 uint32_t code, opcode;
94 uint nargs, argsize;
95 int error;
96
97 /* system call accounting */
98 curcpu()->ci_data.cpu_nsyscall++;
99
100 /* XXX do we want do do emulation? */
101 md_syscall_get_opcode(ucp, &opcode);
102 md_syscall_get_syscallnumber(ucp, &code);
103 code &= (SYS_NSYSENT -1);
104
105 callp = p->p_emul->e_sysent + code;
106 nargs = callp->sy_narg;
107 argsize = callp->sy_argsize;
108
109 args = copyargs;
110 rval[0] = rval[1] = 0;
111 error = md_syscall_getargs(l, ucp, nargs, argsize, args);
112
113 #if 0
114 aprint_debug("syscall no. %d, ", code);
115 aprint_debug("nargs %d, argsize %d => ", nargs, argsize);
116 thunk_printf_debug("syscall no. %d, ", code);
117 thunk_printf_debug("nargs %d, argsize %d => ", nargs, argsize);
118 #endif
119
120 /*
121 * TODO change the pre and post printing into functions so they can be
122 * easily adjusted and dont clobber up this space
123 */
124
125 if (!error)
126 syscall_args_print(l, code, nargs, argsize, args);
127
128 md_syscall_inc_pc(ucp, opcode);
129
130 if (!error) {
131 error = sy_invoke(callp, l, args, rval, code);
132 }
133
134 syscall_retvals_print(l, curlwp, code, nargs, args, error, rval);
135
136 //out:
137 switch (error) {
138 default:
139 /* FALLTHROUGH */
140 case 0:
141 md_syscall_set_returnargs(l, ucp, error, rval);
142 /* FALLTHROUGH */
143 case EJUSTRETURN:
144 break;
145 case ERESTART:
146 md_syscall_dec_pc(ucp, opcode);
147 /* nothing to do */
148 break;
149 }
150 //thunk_printf_debug("end of syscall : return to userland\n");
151 //if (code != 4) thunk_printf("userret() code %d\n", code);
152 }
153
154
155 static void
syscall_args_print(lwp_t * l,int code,int nargs,int argsize,register_t * args)156 syscall_args_print(lwp_t *l, int code, int nargs, int argsize, register_t *args)
157 {
158 char **argv, **envp;
159
160 return;
161 if (code != 4) {
162 thunk_printf("lwp %p, code %3d, nargs %d, argsize %3d\t%s(",
163 l, code, nargs, argsize, syscallnames[code]);
164 switch (code) {
165 case 5:
166 thunk_printf("\"%s\", %"PRIx32", %"PRIx32"", (char *) (args[0]), (uint) args[1], (uint) args[2]);
167 break;
168 case 33:
169 thunk_printf("\"%s\", %"PRIx32"", (char *) (args[0]), (uint) args[1]);
170 break;
171 case 50:
172 thunk_printf("\"%s\"", (char *) (args[0]));
173 break;
174 case 58:
175 thunk_printf("\"%s\", %"PRIx32", %"PRIx32"", (char *) (args[0]), (uint) (args[1]), (uint) args[2]);
176 break;
177 case 59:
178 thunk_printf("\"%s\", [", (char *) (args[0]));
179 argv = (char **) (args[1]);
180 if (*argv) {
181 while (*argv) {
182 thunk_printf("\"%s\", ", *argv);
183 argv++;
184 }
185 thunk_printf("\b\b");
186 }
187 thunk_printf("], [");
188 envp = (char **) (args[2]);
189 if (*envp) {
190 while (*envp) {
191 thunk_printf("\"%s\", ", *envp);
192 envp++;
193 }
194 thunk_printf("\b\b");
195 }
196 thunk_printf("]");
197 break;
198 default:
199 for (int i = 0; i < nargs; i++)
200 thunk_printf("%"PRIx32", ", (uint) args[i]);
201 if (nargs)
202 thunk_printf("\b\b");
203 }
204 thunk_printf(") ");
205 }
206 #if 0
207 if ((code == 4)) {
208 // thunk_printf_debug("[us] %s", (char *) args[1]);
209 thunk_printf("[us] %s", (char *) args[1]);
210 }
211 #endif
212 }
213
214
215 static void
syscall_retvals_print(lwp_t * l,lwp_t * clwp,int code,int nargs,register_t * args,int error,register_t * rval)216 syscall_retvals_print(lwp_t *l, lwp_t *clwp, int code, int nargs, register_t *args, int error, register_t *rval)
217 {
218 char const *errstr;
219
220 return;
221 switch (error) {
222 case EJUSTRETURN:
223 errstr = "EJUSTRETURN";
224 break;
225 case EAGAIN:
226 errstr = "EGAIN";
227 break;
228 default:
229 errstr = "OK";
230 }
231 if (code != 4)
232 thunk_printf("=> %s: %d, (%"PRIx32", %"PRIx32")\n",
233 errstr, error, (uint) (rval[0]), (uint) (rval[1]));
234 }
235