xref: /openbmc/qemu/bsd-user/freebsd/os-syscall.c (revision c7b62b4a)
1 /*
2  *  BSD syscalls
3  *
4  *  Copyright (c) 2003-2008 Fabrice Bellard
5  *  Copyright (c) 2013-2014 Stacey D. Son
6  *
7  *  This program is free software; you can redistribute it and/or modify
8  *  it under the terms of the GNU General Public License as published by
9  *  the Free Software Foundation; either version 2 of the License, or
10  *  (at your option) any later version.
11  *
12  *  This program is distributed in the hope that it will be useful,
13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *  GNU General Public License for more details.
16  *
17  *  You should have received a copy of the GNU General Public License
18  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 /*
22  * We need the FreeBSD "legacy" definitions. Rust needs the FreeBSD 11 system
23  * calls since it doesn't use libc at all, so we have to emulate that despite
24  * FreeBSD 11 being EOL'd.
25  */
26 #define _WANT_FREEBSD11_STAT
27 #define _WANT_FREEBSD11_STATFS
28 #define _WANT_FREEBSD11_DIRENT
29 #define _WANT_KERNEL_ERRNO
30 #define _WANT_SEMUN
31 #include "qemu/osdep.h"
32 #include "qemu/cutils.h"
33 #include "qemu/path.h"
34 #include <sys/syscall.h>
35 #include <sys/param.h>
36 #include <sys/mount.h>
37 #include <sys/sysctl.h>
38 #include <utime.h>
39 
40 #include "qemu.h"
41 #include "signal-common.h"
42 #include "user/syscall-trace.h"
43 
44 #include "bsd-file.h"
45 #include "bsd-proc.h"
46 
47 /* I/O */
48 safe_syscall3(int, open, const char *, path, int, flags, mode_t, mode);
49 safe_syscall4(int, openat, int, fd, const char *, path, int, flags, mode_t,
50     mode);
51 
52 safe_syscall3(ssize_t, read, int, fd, void *, buf, size_t, nbytes);
53 safe_syscall4(ssize_t, pread, int, fd, void *, buf, size_t, nbytes, off_t,
54     offset);
55 safe_syscall3(ssize_t, readv, int, fd, const struct iovec *, iov, int, iovcnt);
56 safe_syscall4(ssize_t, preadv, int, fd, const struct iovec *, iov, int, iovcnt,
57     off_t, offset);
58 
59 safe_syscall3(ssize_t, write, int, fd, void *, buf, size_t, nbytes);
60 safe_syscall4(ssize_t, pwrite, int, fd, void *, buf, size_t, nbytes, off_t,
61     offset);
62 safe_syscall3(ssize_t, writev, int, fd, const struct iovec *, iov, int, iovcnt);
63 safe_syscall4(ssize_t, pwritev, int, fd, const struct iovec *, iov, int, iovcnt,
64     off_t, offset);
65 
66 void target_set_brk(abi_ulong new_brk)
67 {
68 }
69 
70 /*
71  * errno conversion.
72  */
73 abi_long get_errno(abi_long ret)
74 {
75     if (ret == -1) {
76         return -host_to_target_errno(errno);
77     } else {
78         return ret;
79     }
80 }
81 
82 int host_to_target_errno(int err)
83 {
84     /*
85      * All the BSDs have the property that the error numbers are uniform across
86      * all architectures for a given BSD, though they may vary between different
87      * BSDs.
88      */
89     return err;
90 }
91 
92 bool is_error(abi_long ret)
93 {
94     return (abi_ulong)ret >= (abi_ulong)(-4096);
95 }
96 
97 /*
98  * Unlocks a iovec. Unlike unlock_iovec, it assumes the tvec array itself is
99  * already locked from target_addr. It will be unlocked as well as all the iovec
100  * elements.
101  */
102 static void helper_unlock_iovec(struct target_iovec *target_vec,
103                                 abi_ulong target_addr, struct iovec *vec,
104                                 int count, int copy)
105 {
106     for (int i = 0; i < count; i++) {
107         abi_ulong base = tswapal(target_vec[i].iov_base);
108 
109         if (vec[i].iov_base) {
110             unlock_user(vec[i].iov_base, base, copy ? vec[i].iov_len : 0);
111         }
112     }
113     unlock_user(target_vec, target_addr, 0);
114 }
115 
116 struct iovec *lock_iovec(int type, abi_ulong target_addr,
117         int count, int copy)
118 {
119     struct target_iovec *target_vec;
120     struct iovec *vec;
121     abi_ulong total_len, max_len;
122     int i;
123     int err = 0;
124 
125     if (count == 0) {
126         errno = 0;
127         return NULL;
128     }
129     if (count < 0 || count > IOV_MAX) {
130         errno = EINVAL;
131         return NULL;
132     }
133 
134     vec = g_try_new0(struct iovec, count);
135     if (vec == NULL) {
136         errno = ENOMEM;
137         return NULL;
138     }
139 
140     target_vec = lock_user(VERIFY_READ, target_addr,
141                            count * sizeof(struct target_iovec), 1);
142     if (target_vec == NULL) {
143         err = EFAULT;
144         goto fail2;
145     }
146 
147     max_len = 0x7fffffff & MIN(TARGET_PAGE_MASK, PAGE_MASK);
148     total_len = 0;
149 
150     for (i = 0; i < count; i++) {
151         abi_ulong base = tswapal(target_vec[i].iov_base);
152         abi_long len = tswapal(target_vec[i].iov_len);
153 
154         if (len < 0) {
155             err = EINVAL;
156             goto fail;
157         } else if (len == 0) {
158             /* Zero length pointer is ignored. */
159             vec[i].iov_base = 0;
160         } else {
161             vec[i].iov_base = lock_user(type, base, len, copy);
162             /*
163              * If the first buffer pointer is bad, this is a fault.  But
164              * subsequent bad buffers will result in a partial write; this is
165              * realized by filling the vector with null pointers and zero
166              * lengths.
167              */
168             if (!vec[i].iov_base) {
169                 if (i == 0) {
170                     err = EFAULT;
171                     goto fail;
172                 } else {
173                     /*
174                      * Fail all the subsequent addresses, they are already
175                      * zero'd.
176                      */
177                     goto out;
178                 }
179             }
180             if (len > max_len - total_len) {
181                 len = max_len - total_len;
182             }
183         }
184         vec[i].iov_len = len;
185         total_len += len;
186     }
187 out:
188     unlock_user(target_vec, target_addr, 0);
189     return vec;
190 
191 fail:
192     helper_unlock_iovec(target_vec, target_addr, vec, i, copy);
193 fail2:
194     g_free(vec);
195     errno = err;
196     return NULL;
197 }
198 
199 void unlock_iovec(struct iovec *vec, abi_ulong target_addr,
200         int count, int copy)
201 {
202     struct target_iovec *target_vec;
203 
204     target_vec = lock_user(VERIFY_READ, target_addr,
205                            count * sizeof(struct target_iovec), 1);
206     if (target_vec) {
207         helper_unlock_iovec(target_vec, target_addr, vec, count, copy);
208     }
209 
210     g_free(vec);
211 }
212 
213 /*
214  * All errnos that freebsd_syscall() returns must be -TARGET_<errcode>.
215  */
216 static abi_long freebsd_syscall(void *cpu_env, int num, abi_long arg1,
217                                 abi_long arg2, abi_long arg3, abi_long arg4,
218                                 abi_long arg5, abi_long arg6, abi_long arg7,
219                                 abi_long arg8)
220 {
221     abi_long ret;
222 
223     switch (num) {
224         /*
225          * process system calls
226          */
227     case TARGET_FREEBSD_NR_exit: /* exit(2) */
228         ret = do_bsd_exit(cpu_env, arg1);
229         break;
230 
231         /*
232          * File system calls.
233          */
234     case TARGET_FREEBSD_NR_read: /* read(2) */
235         ret = do_bsd_read(arg1, arg2, arg3);
236         break;
237 
238     case TARGET_FREEBSD_NR_pread: /* pread(2) */
239         ret = do_bsd_pread(cpu_env, arg1, arg2, arg3, arg4, arg5, arg6);
240         break;
241 
242     case TARGET_FREEBSD_NR_readv: /* readv(2) */
243         ret = do_bsd_readv(arg1, arg2, arg3);
244         break;
245 
246     case TARGET_FREEBSD_NR_preadv: /* preadv(2) */
247         ret = do_bsd_preadv(cpu_env, arg1, arg2, arg3, arg4, arg5, arg6);
248 
249     case TARGET_FREEBSD_NR_write: /* write(2) */
250         ret = do_bsd_write(arg1, arg2, arg3);
251         break;
252 
253     case TARGET_FREEBSD_NR_pwrite: /* pwrite(2) */
254         ret = do_bsd_pwrite(cpu_env, arg1, arg2, arg3, arg4, arg5, arg6);
255         break;
256 
257     case TARGET_FREEBSD_NR_writev: /* writev(2) */
258         ret = do_bsd_writev(arg1, arg2, arg3);
259         break;
260 
261     case TARGET_FREEBSD_NR_pwritev: /* pwritev(2) */
262         ret = do_bsd_pwritev(cpu_env, arg1, arg2, arg3, arg4, arg5, arg6);
263         break;
264 
265     case TARGET_FREEBSD_NR_open: /* open(2) */
266         ret = do_bsd_open(arg1, arg2, arg3);
267         break;
268 
269     case TARGET_FREEBSD_NR_openat: /* openat(2) */
270         ret = do_bsd_openat(arg1, arg2, arg3, arg4);
271         break;
272 
273     case TARGET_FREEBSD_NR_close: /* close(2) */
274         ret = do_bsd_close(arg1);
275         break;
276 
277     case TARGET_FREEBSD_NR_fdatasync: /* fdatasync(2) */
278         ret = do_bsd_fdatasync(arg1);
279         break;
280 
281     case TARGET_FREEBSD_NR_fsync: /* fsync(2) */
282         ret = do_bsd_fsync(arg1);
283         break;
284 
285     case TARGET_FREEBSD_NR_freebsd12_closefrom: /* closefrom(2) */
286         ret = do_bsd_closefrom(arg1);
287         break;
288 
289     case TARGET_FREEBSD_NR_revoke: /* revoke(2) */
290         ret = do_bsd_revoke(arg1);
291         break;
292 
293     case TARGET_FREEBSD_NR_access: /* access(2) */
294         ret = do_bsd_access(arg1, arg2);
295         break;
296 
297     case TARGET_FREEBSD_NR_eaccess: /* eaccess(2) */
298         ret = do_bsd_eaccess(arg1, arg2);
299         break;
300 
301     case TARGET_FREEBSD_NR_faccessat: /* faccessat(2) */
302         ret = do_bsd_faccessat(arg1, arg2, arg3, arg4);
303         break;
304 
305     case TARGET_FREEBSD_NR_chdir: /* chdir(2) */
306         ret = do_bsd_chdir(arg1);
307         break;
308 
309     case TARGET_FREEBSD_NR_fchdir: /* fchdir(2) */
310         ret = do_bsd_fchdir(arg1);
311         break;
312 
313     case TARGET_FREEBSD_NR_rename: /* rename(2) */
314         ret = do_bsd_rename(arg1, arg2);
315         break;
316 
317     case TARGET_FREEBSD_NR_renameat: /* renameat(2) */
318         ret = do_bsd_renameat(arg1, arg2, arg3, arg4);
319         break;
320 
321     case TARGET_FREEBSD_NR_link: /* link(2) */
322         ret = do_bsd_link(arg1, arg2);
323         break;
324 
325     case TARGET_FREEBSD_NR_linkat: /* linkat(2) */
326         ret = do_bsd_linkat(arg1, arg2, arg3, arg4, arg5);
327         break;
328 
329     case TARGET_FREEBSD_NR_unlink: /* unlink(2) */
330         ret = do_bsd_unlink(arg1);
331         break;
332 
333     case TARGET_FREEBSD_NR_unlinkat: /* unlinkat(2) */
334         ret = do_bsd_unlinkat(arg1, arg2, arg3);
335         break;
336 
337     case TARGET_FREEBSD_NR_mkdir: /* mkdir(2) */
338         ret = do_bsd_mkdir(arg1, arg2);
339         break;
340 
341     case TARGET_FREEBSD_NR_mkdirat: /* mkdirat(2) */
342         ret = do_bsd_mkdirat(arg1, arg2, arg3);
343         break;
344 
345     case TARGET_FREEBSD_NR_rmdir: /* rmdir(2) (XXX no rmdirat()?) */
346         ret = do_bsd_rmdir(arg1);
347         break;
348 
349     case TARGET_FREEBSD_NR___getcwd: /* undocumented __getcwd() */
350         ret = do_bsd___getcwd(arg1, arg2);
351         break;
352 
353     case TARGET_FREEBSD_NR_dup: /* dup(2) */
354         ret = do_bsd_dup(arg1);
355         break;
356 
357     case TARGET_FREEBSD_NR_dup2: /* dup2(2) */
358         ret = do_bsd_dup2(arg1, arg2);
359         break;
360 
361     case TARGET_FREEBSD_NR_truncate: /* truncate(2) */
362         ret = do_bsd_truncate(cpu_env, arg1, arg2, arg3, arg4);
363         break;
364 
365     case TARGET_FREEBSD_NR_ftruncate: /* ftruncate(2) */
366         ret = do_bsd_ftruncate(cpu_env, arg1, arg2, arg3, arg4);
367         break;
368 
369     case TARGET_FREEBSD_NR_acct: /* acct(2) */
370         ret = do_bsd_acct(arg1);
371         break;
372 
373     case TARGET_FREEBSD_NR_sync: /* sync(2) */
374         ret = do_bsd_sync();
375         break;
376 
377     case TARGET_FREEBSD_NR_mount: /* mount(2) */
378         ret = do_bsd_mount(arg1, arg2, arg3, arg4);
379         break;
380 
381     case TARGET_FREEBSD_NR_unmount: /* unmount(2) */
382         ret = do_bsd_unmount(arg1, arg2);
383         break;
384 
385     case TARGET_FREEBSD_NR_nmount: /* nmount(2) */
386         ret = do_bsd_nmount(arg1, arg2, arg3);
387         break;
388 
389     case TARGET_FREEBSD_NR_symlink: /* symlink(2) */
390         ret = do_bsd_symlink(arg1, arg2);
391         break;
392 
393     case TARGET_FREEBSD_NR_symlinkat: /* symlinkat(2) */
394         ret = do_bsd_symlinkat(arg1, arg2, arg3);
395         break;
396 
397     case TARGET_FREEBSD_NR_readlink: /* readlink(2) */
398         ret = do_bsd_readlink(cpu_env, arg1, arg2, arg3);
399         break;
400 
401     case TARGET_FREEBSD_NR_readlinkat: /* readlinkat(2) */
402         ret = do_bsd_readlinkat(arg1, arg2, arg3, arg4);
403         break;
404 
405     default:
406         qemu_log_mask(LOG_UNIMP, "Unsupported syscall: %d\n", num);
407         ret = -TARGET_ENOSYS;
408         break;
409     }
410 
411     return ret;
412 }
413 
414 /*
415  * do_freebsd_syscall() should always have a single exit point at the end so
416  * that actions, such as logging of syscall results, can be performed. This
417  * as a wrapper around freebsd_syscall() so that actually happens. Since
418  * that is a singleton, modern compilers will inline it anyway...
419  */
420 abi_long do_freebsd_syscall(void *cpu_env, int num, abi_long arg1,
421                             abi_long arg2, abi_long arg3, abi_long arg4,
422                             abi_long arg5, abi_long arg6, abi_long arg7,
423                             abi_long arg8)
424 {
425     CPUState *cpu = env_cpu(cpu_env);
426     int ret;
427 
428     trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
429     if (do_strace) {
430         print_freebsd_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
431     }
432 
433     ret = freebsd_syscall(cpu_env, num, arg1, arg2, arg3, arg4, arg5, arg6,
434                           arg7, arg8);
435     if (do_strace) {
436         print_freebsd_syscall_ret(num, ret);
437     }
438     trace_guest_user_syscall_ret(cpu, num, ret);
439 
440     return ret;
441 }
442 
443 void syscall_init(void)
444 {
445 }
446