bsd-user/freebsd/os-syscall.c

   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/sysctl.h>
  37 #include <utime.h>
  38
  39 #include "qemu.h"
  40 #include "signal-common.h"
  41 #include "user/syscall-trace.h"
  42
  43 #include "bsd-file.h"
  44 #include "bsd-proc.h"
  45
  46 /* I/O */
  47 safe_syscall3(ssize_t, read, int, fd, void *, buf, size_t, nbytes);
  48 safe_syscall4(ssize_t, pread, int, fd, void *, buf, size_t, nbytes, off_t,
  49     offset);
  50 safe_syscall3(ssize_t, readv, int, fd, const struct iovec *, iov, int, iovcnt);
  51 safe_syscall4(ssize_t, preadv, int, fd, const struct iovec *, iov, int, iovcnt,
  52     off_t, offset);
  53
  54 safe_syscall3(ssize_t, write, int, fd, void *, buf, size_t, nbytes);
  55 safe_syscall4(ssize_t, pwrite, int, fd, void *, buf, size_t, nbytes, off_t,
  56     offset);
  57 safe_syscall3(ssize_t, writev, int, fd, const struct iovec *, iov, int, iovcnt);
  58 safe_syscall4(ssize_t, pwritev, int, fd, const struct iovec *, iov, int, iovcnt,
  59     off_t, offset);
  60
  61 void target_set_brk(abi_ulong new_brk)
  62 {
  63 }
  64
  65 /*
  66  * errno conversion.
  67  */
  68 abi_long get_errno(abi_long ret)
  69 {
  70     if (ret == -1) {
  71         return -host_to_target_errno(errno);
  72     } else {
  73         return ret;
  74     }
  75 }
  76
  77 int host_to_target_errno(int err)
  78 {
  79     /*
  80      * All the BSDs have the property that the error numbers are uniform across
  81      * all architectures for a given BSD, though they may vary between different
  82      * BSDs.
  83      */
  84     return err;
  85 }
  86
  87 bool is_error(abi_long ret)
  88 {
  89     return (abi_ulong)ret >= (abi_ulong)(-4096);
  90 }
  91
  92 /*
  93  * Unlocks a iovec. Unlike unlock_iovec, it assumes the tvec array itself is
  94  * already locked from target_addr. It will be unlocked as well as all the iovec
  95  * elements.
  96  */
  97 static void helper_unlock_iovec(struct target_iovec *target_vec,
  98                                 abi_ulong target_addr, struct iovec *vec,
  99                                 int count, int copy)
 100 {
 101     for (int i = 0; i < count; i++) {
 102         abi_ulong base = tswapal(target_vec[i].iov_base);
 103
 104         if (vec[i].iov_base) {
 105             unlock_user(vec[i].iov_base, base, copy ? vec[i].iov_len : 0);
 106         }
 107     }
 108     unlock_user(target_vec, target_addr, 0);
 109 }
 110
 111 struct iovec *lock_iovec(int type, abi_ulong target_addr,
 112         int count, int copy)
 113 {
 114     struct target_iovec *target_vec;
 115     struct iovec *vec;
 116     abi_ulong total_len, max_len;
 117     int i;
 118     int err = 0;
 119
 120     if (count == 0) {
 121         errno = 0;
 122         return NULL;
 123     }
 124     if (count < 0 || count > IOV_MAX) {
 125         errno = EINVAL;
 126         return NULL;
 127     }
 128
 129     vec = g_try_new0(struct iovec, count);
 130     if (vec == NULL) {
 131         errno = ENOMEM;
 132         return NULL;
 133     }
 134
 135     target_vec = lock_user(VERIFY_READ, target_addr,
 136                            count * sizeof(struct target_iovec), 1);
 137     if (target_vec == NULL) {
 138         err = EFAULT;
 139         goto fail2;
 140     }
 141
 142     max_len = 0x7fffffff & MIN(TARGET_PAGE_MASK, PAGE_MASK);
 143     total_len = 0;
 144
 145     for (i = 0; i < count; i++) {
 146         abi_ulong base = tswapal(target_vec[i].iov_base);
 147         abi_long len = tswapal(target_vec[i].iov_len);
 148
 149         if (len < 0) {
 150             err = EINVAL;
 151             goto fail;
 152         } else if (len == 0) {
 153             /* Zero length pointer is ignored. */
 154             vec[i].iov_base = 0;
 155         } else {
 156             vec[i].iov_base = lock_user(type, base, len, copy);
 157             /*
 158              * If the first buffer pointer is bad, this is a fault.  But
 159              * subsequent bad buffers will result in a partial write; this is
 160              * realized by filling the vector with null pointers and zero
 161              * lengths.
 162              */
 163             if (!vec[i].iov_base) {
 164                 if (i == 0) {
 165                     err = EFAULT;
 166                     goto fail;
 167                 } else {
 168                     /*
 169                      * Fail all the subsequent addresses, they are already
 170                      * zero'd.
 171                      */
 172                     goto out;
 173                 }
 174             }
 175             if (len > max_len - total_len) {
 176                 len = max_len - total_len;
 177             }
 178         }
 179         vec[i].iov_len = len;
 180         total_len += len;
 181     }
 182 out:
 183     unlock_user(target_vec, target_addr, 0);
 184     return vec;
 185
 186 fail:
 187     helper_unlock_iovec(target_vec, target_addr, vec, i, copy);
 188 fail2:
 189     g_free(vec);
 190     errno = err;
 191     return NULL;
 192 }
 193
 194 void unlock_iovec(struct iovec *vec, abi_ulong target_addr,
 195         int count, int copy)
 196 {
 197     struct target_iovec *target_vec;
 198
 199     target_vec = lock_user(VERIFY_READ, target_addr,
 200                            count * sizeof(struct target_iovec), 1);
 201     if (target_vec) {
 202         helper_unlock_iovec(target_vec, target_addr, vec, count, copy);
 203     }
 204
 205     g_free(vec);
 206 }
 207
 208 /*
 209  * All errnos that freebsd_syscall() returns must be -TARGET_<errcode>.
 210  */
 211 static abi_long freebsd_syscall(void *cpu_env, int num, abi_long arg1,
 212                                 abi_long arg2, abi_long arg3, abi_long arg4,
 213                                 abi_long arg5, abi_long arg6, abi_long arg7,
 214                                 abi_long arg8)
 215 {
 216     abi_long ret;
 217
 218     switch (num) {
 219         /*
 220          * process system calls
 221          */
 222     case TARGET_FREEBSD_NR_exit: /* exit(2) */
 223         ret = do_bsd_exit(cpu_env, arg1);
 224         break;
 225
 226         /*
 227          * File system calls.
 228          */
 229     case TARGET_FREEBSD_NR_read: /* read(2) */
 230         ret = do_bsd_read(arg1, arg2, arg3);
 231         break;
 232
 233     case TARGET_FREEBSD_NR_pread: /* pread(2) */
 234         ret = do_bsd_pread(cpu_env, arg1, arg2, arg3, arg4, arg5, arg6);
 235         break;
 236
 237     case TARGET_FREEBSD_NR_readv: /* readv(2) */
 238         ret = do_bsd_readv(arg1, arg2, arg3);
 239         break;
 240
 241     case TARGET_FREEBSD_NR_preadv: /* preadv(2) */
 242         ret = do_bsd_preadv(cpu_env, arg1, arg2, arg3, arg4, arg5, arg6);
 243
 244     case TARGET_FREEBSD_NR_write: /* write(2) */
 245         ret = do_bsd_write(arg1, arg2, arg3);
 246         break;
 247
 248     case TARGET_FREEBSD_NR_pwrite: /* pwrite(2) */
 249         ret = do_bsd_pwrite(cpu_env, arg1, arg2, arg3, arg4, arg5, arg6);
 250         break;
 251
 252     case TARGET_FREEBSD_NR_writev: /* writev(2) */
 253         ret = do_bsd_writev(arg1, arg2, arg3);
 254         break;
 255
 256     case TARGET_FREEBSD_NR_pwritev: /* pwritev(2) */
 257         ret = do_bsd_pwritev(cpu_env, arg1, arg2, arg3, arg4, arg5, arg6);
 258         break;
 259
 260     default:
 261         qemu_log_mask(LOG_UNIMP, "Unsupported syscall: %d\n", num);
 262         ret = -TARGET_ENOSYS;
 263         break;
 264     }
 265
 266     return ret;
 267 }
 268
 269 /*
 270  * do_freebsd_syscall() should always have a single exit point at the end so
 271  * that actions, such as logging of syscall results, can be performed. This
 272  * as a wrapper around freebsd_syscall() so that actually happens. Since
 273  * that is a singleton, modern compilers will inline it anyway...
 274  */
 275 abi_long do_freebsd_syscall(void *cpu_env, int num, abi_long arg1,
 276                             abi_long arg2, abi_long arg3, abi_long arg4,
 277                             abi_long arg5, abi_long arg6, abi_long arg7,
 278                             abi_long arg8)
 279 {
 280     CPUState *cpu = env_cpu(cpu_env);
 281     int ret;
 282
 283     trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
 284     if (do_strace) {
 285         print_freebsd_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
 286     }
 287
 288     ret = freebsd_syscall(cpu_env, num, arg1, arg2, arg3, arg4, arg5, arg6,
 289                           arg7, arg8);
 290     if (do_strace) {
 291         print_freebsd_syscall_ret(num, ret);
 292     }
 293     trace_guest_user_syscall_ret(cpu, num, ret);
 294
 295     return ret;
 296 }
 297
 298 void syscall_init(void)
 299 {
 300 }