arch/s390/kernel/compat_linux.c

   1 /*
   2  *  S390 version
   3  *    Copyright IBM Corp. 2000
   4  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   5  *               Gerhard Tonn (ton@de.ibm.com)
   6  *               Thomas Spatzier (tspat@de.ibm.com)
   7  *
   8  *  Conversion between 31bit and 64bit native syscalls.
   9  *
  10  * Heavily inspired by the 32-bit Sparc compat code which is
  11  * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
  12  * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
  13  *
  14  */
  15
  16
  17 #include <linux/kernel.h>
  18 #include <linux/sched.h>
  19 #include <linux/fs.h>
  20 #include <linux/mm.h>
  21 #include <linux/file.h>
  22 #include <linux/signal.h>
  23 #include <linux/resource.h>
  24 #include <linux/times.h>
  25 #include <linux/smp.h>
  26 #include <linux/sem.h>
  27 #include <linux/msg.h>
  28 #include <linux/shm.h>
  29 #include <linux/uio.h>
  30 #include <linux/quota.h>
  31 #include <linux/module.h>
  32 #include <linux/poll.h>
  33 #include <linux/personality.h>
  34 #include <linux/stat.h>
  35 #include <linux/filter.h>
  36 #include <linux/highmem.h>
  37 #include <linux/highuid.h>
  38 #include <linux/mman.h>
  39 #include <linux/ipv6.h>
  40 #include <linux/in.h>
  41 #include <linux/icmpv6.h>
  42 #include <linux/syscalls.h>
  43 #include <linux/sysctl.h>
  44 #include <linux/binfmts.h>
  45 #include <linux/capability.h>
  46 #include <linux/compat.h>
  47 #include <linux/vfs.h>
  48 #include <linux/ptrace.h>
  49 #include <linux/fadvise.h>
  50 #include <linux/ipc.h>
  51 #include <linux/slab.h>
  52
  53 #include <asm/types.h>
  54 #include <asm/uaccess.h>
  55
  56 #include <net/scm.h>
  57 #include <net/sock.h>
  58
  59 #include "compat_linux.h"
  60
  61 u32 psw32_user_bits = PSW32_MASK_DAT | PSW32_MASK_IO | PSW32_MASK_EXT |
  62                       PSW32_DEFAULT_KEY | PSW32_MASK_BASE | PSW32_MASK_MCHECK |
  63                       PSW32_MASK_PSTATE | PSW32_ASC_HOME;
  64
  65 /* For this source file, we want overflow handling. */
  66
  67 #undef high2lowuid
  68 #undef high2lowgid
  69 #undef low2highuid
  70 #undef low2highgid
  71 #undef SET_UID16
  72 #undef SET_GID16
  73 #undef NEW_TO_OLD_UID
  74 #undef NEW_TO_OLD_GID
  75 #undef SET_OLDSTAT_UID
  76 #undef SET_OLDSTAT_GID
  77 #undef SET_STAT_UID
  78 #undef SET_STAT_GID
  79
  80 #define high2lowuid(uid) ((uid) > 65535) ? (u16)overflowuid : (u16)(uid)
  81 #define high2lowgid(gid) ((gid) > 65535) ? (u16)overflowgid : (u16)(gid)
  82 #define low2highuid(uid) ((uid) == (u16)-1) ? (uid_t)-1 : (uid_t)(uid)
  83 #define low2highgid(gid) ((gid) == (u16)-1) ? (gid_t)-1 : (gid_t)(gid)
  84 #define SET_UID16(var, uid)     var = high2lowuid(uid)
  85 #define SET_GID16(var, gid)     var = high2lowgid(gid)
  86 #define NEW_TO_OLD_UID(uid)     high2lowuid(uid)
  87 #define NEW_TO_OLD_GID(gid)     high2lowgid(gid)
  88 #define SET_OLDSTAT_UID(stat, uid)      (stat).st_uid = high2lowuid(uid)
  89 #define SET_OLDSTAT_GID(stat, gid)      (stat).st_gid = high2lowgid(gid)
  90 #define SET_STAT_UID(stat, uid)         (stat).st_uid = high2lowuid(uid)
  91 #define SET_STAT_GID(stat, gid)         (stat).st_gid = high2lowgid(gid)
  92
  93 asmlinkage long sys32_chown16(const char __user * filename, u16 user, u16 group)
  94 {
  95         return sys_chown(filename, low2highuid(user), low2highgid(group));
  96 }
  97
  98 asmlinkage long sys32_lchown16(const char __user * filename, u16 user, u16 group)
  99 {
 100         return sys_lchown(filename, low2highuid(user), low2highgid(group));
 101 }
 102
 103 asmlinkage long sys32_fchown16(unsigned int fd, u16 user, u16 group)
 104 {
 105         return sys_fchown(fd, low2highuid(user), low2highgid(group));
 106 }
 107
 108 asmlinkage long sys32_setregid16(u16 rgid, u16 egid)
 109 {
 110         return sys_setregid(low2highgid(rgid), low2highgid(egid));
 111 }
 112
 113 asmlinkage long sys32_setgid16(u16 gid)
 114 {
 115         return sys_setgid((gid_t)gid);
 116 }
 117
 118 asmlinkage long sys32_setreuid16(u16 ruid, u16 euid)
 119 {
 120         return sys_setreuid(low2highuid(ruid), low2highuid(euid));
 121 }
 122
 123 asmlinkage long sys32_setuid16(u16 uid)
 124 {
 125         return sys_setuid((uid_t)uid);
 126 }
 127
 128 asmlinkage long sys32_setresuid16(u16 ruid, u16 euid, u16 suid)
 129 {
 130         return sys_setresuid(low2highuid(ruid), low2highuid(euid),
 131                 low2highuid(suid));
 132 }
 133
 134 asmlinkage long sys32_getresuid16(u16 __user *ruid, u16 __user *euid, u16 __user *suid)
 135 {
 136         int retval;
 137
 138         if (!(retval = put_user(high2lowuid(current->cred->uid), ruid)) &&
 139             !(retval = put_user(high2lowuid(current->cred->euid), euid)))
 140                 retval = put_user(high2lowuid(current->cred->suid), suid);
 141
 142         return retval;
 143 }
 144
 145 asmlinkage long sys32_setresgid16(u16 rgid, u16 egid, u16 sgid)
 146 {
 147         return sys_setresgid(low2highgid(rgid), low2highgid(egid),
 148                 low2highgid(sgid));
 149 }
 150
 151 asmlinkage long sys32_getresgid16(u16 __user *rgid, u16 __user *egid, u16 __user *sgid)
 152 {
 153         int retval;
 154
 155         if (!(retval = put_user(high2lowgid(current->cred->gid), rgid)) &&
 156             !(retval = put_user(high2lowgid(current->cred->egid), egid)))
 157                 retval = put_user(high2lowgid(current->cred->sgid), sgid);
 158
 159         return retval;
 160 }
 161
 162 asmlinkage long sys32_setfsuid16(u16 uid)
 163 {
 164         return sys_setfsuid((uid_t)uid);
 165 }
 166
 167 asmlinkage long sys32_setfsgid16(u16 gid)
 168 {
 169         return sys_setfsgid((gid_t)gid);
 170 }
 171
 172 static int groups16_to_user(u16 __user *grouplist, struct group_info *group_info)
 173 {
 174         struct user_namespace *user_ns = current_user_ns();
 175         int i;
 176         u16 group;
 177         kgid_t kgid;
 178
 179         for (i = 0; i < group_info->ngroups; i++) {
 180                 kgid = GROUP_AT(group_info, i);
 181                 group = (u16)from_kgid_munged(user_ns, kgid);
 182                 if (put_user(group, grouplist+i))
 183                         return -EFAULT;
 184         }
 185
 186         return 0;
 187 }
 188
 189 static int groups16_from_user(struct group_info *group_info, u16 __user *grouplist)
 190 {
 191         struct user_namespace *user_ns = current_user_ns();
 192         int i;
 193         u16 group;
 194         kgid_t kgid;
 195
 196         for (i = 0; i < group_info->ngroups; i++) {
 197                 if (get_user(group, grouplist+i))
 198                         return  -EFAULT;
 199
 200                 kgid = make_kgid(user_ns, (gid_t)group);
 201                 if (!gid_valid(kgid))
 202                         return -EINVAL;
 203
 204                 GROUP_AT(group_info, i) = kgid;
 205         }
 206
 207         return 0;
 208 }
 209
 210 asmlinkage long sys32_getgroups16(int gidsetsize, u16 __user *grouplist)
 211 {
 212         int i;
 213
 214         if (gidsetsize < 0)
 215                 return -EINVAL;
 216
 217         get_group_info(current->cred->group_info);
 218         i = current->cred->group_info->ngroups;
 219         if (gidsetsize) {
 220                 if (i > gidsetsize) {
 221                         i = -EINVAL;
 222                         goto out;
 223                 }
 224                 if (groups16_to_user(grouplist, current->cred->group_info)) {
 225                         i = -EFAULT;
 226                         goto out;
 227                 }
 228         }
 229 out:
 230         put_group_info(current->cred->group_info);
 231         return i;
 232 }
 233
 234 asmlinkage long sys32_setgroups16(int gidsetsize, u16 __user *grouplist)
 235 {
 236         struct group_info *group_info;
 237         int retval;
 238
 239         if (!capable(CAP_SETGID))
 240                 return -EPERM;
 241         if ((unsigned)gidsetsize > NGROUPS_MAX)
 242                 return -EINVAL;
 243
 244         group_info = groups_alloc(gidsetsize);
 245         if (!group_info)
 246                 return -ENOMEM;
 247         retval = groups16_from_user(group_info, grouplist);
 248         if (retval) {
 249                 put_group_info(group_info);
 250                 return retval;
 251         }
 252
 253         retval = set_current_groups(group_info);
 254         put_group_info(group_info);
 255
 256         return retval;
 257 }
 258
 259 asmlinkage long sys32_getuid16(void)
 260 {
 261         return high2lowuid(current->cred->uid);
 262 }
 263
 264 asmlinkage long sys32_geteuid16(void)
 265 {
 266         return high2lowuid(current->cred->euid);
 267 }
 268
 269 asmlinkage long sys32_getgid16(void)
 270 {
 271         return high2lowgid(current->cred->gid);
 272 }
 273
 274 asmlinkage long sys32_getegid16(void)
 275 {
 276         return high2lowgid(current->cred->egid);
 277 }
 278
 279 /*
 280  * sys32_ipc() is the de-multiplexer for the SysV IPC calls in 32bit emulation.
 281  *
 282  * This is really horribly ugly.
 283  */
 284 #ifdef CONFIG_SYSVIPC
 285 asmlinkage long sys32_ipc(u32 call, int first, int second, int third, u32 ptr)
 286 {
 287         if (call >> 16)         /* hack for backward compatibility */
 288                 return -EINVAL;
 289         switch (call) {
 290         case SEMTIMEDOP:
 291                 return compat_sys_semtimedop(first, compat_ptr(ptr),
 292                                              second, compat_ptr(third));
 293         case SEMOP:
 294                 /* struct sembuf is the same on 32 and 64bit :)) */
 295                 return sys_semtimedop(first, compat_ptr(ptr),
 296                                       second, NULL);
 297         case SEMGET:
 298                 return sys_semget(first, second, third);
 299         case SEMCTL:
 300                 return compat_sys_semctl(first, second, third,
 301                                          compat_ptr(ptr));
 302         case MSGSND:
 303                 return compat_sys_msgsnd(first, second, third,
 304                                          compat_ptr(ptr));
 305         case MSGRCV:
 306                 return compat_sys_msgrcv(first, second, 0, third,
 307                                          0, compat_ptr(ptr));
 308         case MSGGET:
 309                 return sys_msgget((key_t) first, second);
 310         case MSGCTL:
 311                 return compat_sys_msgctl(first, second, compat_ptr(ptr));
 312         case SHMAT:
 313                 return compat_sys_shmat(first, second, third,
 314                                         0, compat_ptr(ptr));
 315         case SHMDT:
 316                 return sys_shmdt(compat_ptr(ptr));
 317         case SHMGET:
 318                 return sys_shmget(first, (unsigned)second, third);
 319         case SHMCTL:
 320                 return compat_sys_shmctl(first, second, compat_ptr(ptr));
 321         }
 322
 323         return -ENOSYS;
 324 }
 325 #endif
 326
 327 asmlinkage long sys32_truncate64(const char __user * path, unsigned long high, unsigned long low)
 328 {
 329         if ((int)high < 0)
 330                 return -EINVAL;
 331         else
 332                 return sys_truncate(path, (high << 32) | low);
 333 }
 334
 335 asmlinkage long sys32_ftruncate64(unsigned int fd, unsigned long high, unsigned long low)
 336 {
 337         if ((int)high < 0)
 338                 return -EINVAL;
 339         else
 340                 return sys_ftruncate(fd, (high << 32) | low);
 341 }
 342
 343 asmlinkage long sys32_sched_rr_get_interval(compat_pid_t pid,
 344                                 struct compat_timespec __user *interval)
 345 {
 346         struct timespec t;
 347         int ret;
 348         mm_segment_t old_fs = get_fs ();
 349
 350         set_fs (KERNEL_DS);
 351         ret = sys_sched_rr_get_interval(pid,
 352                                         (struct timespec __force __user *) &t);
 353         set_fs (old_fs);
 354         if (put_compat_timespec(&t, interval))
 355                 return -EFAULT;
 356         return ret;
 357 }
 358
 359 asmlinkage long sys32_rt_sigprocmask(int how, compat_sigset_t __user *set,
 360                         compat_sigset_t __user *oset, size_t sigsetsize)
 361 {
 362         sigset_t s;
 363         compat_sigset_t s32;
 364         int ret;
 365         mm_segment_t old_fs = get_fs();
 366
 367         if (set) {
 368                 if (copy_from_user (&s32, set, sizeof(compat_sigset_t)))
 369                         return -EFAULT;
 370                 s.sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32);
 371         }
 372         set_fs (KERNEL_DS);
 373         ret = sys_rt_sigprocmask(how,
 374                                  set ? (sigset_t __force __user *) &s : NULL,
 375                                  oset ? (sigset_t __force __user *) &s : NULL,
 376                                  sigsetsize);
 377         set_fs (old_fs);
 378         if (ret) return ret;
 379         if (oset) {
 380                 s32.sig[1] = (s.sig[0] >> 32);
 381                 s32.sig[0] = s.sig[0];
 382                 if (copy_to_user (oset, &s32, sizeof(compat_sigset_t)))
 383                         return -EFAULT;
 384         }
 385         return 0;
 386 }
 387
 388 asmlinkage long sys32_rt_sigpending(compat_sigset_t __user *set,
 389                                 size_t sigsetsize)
 390 {
 391         sigset_t s;
 392         compat_sigset_t s32;
 393         int ret;
 394         mm_segment_t old_fs = get_fs();
 395
 396         set_fs (KERNEL_DS);
 397         ret = sys_rt_sigpending((sigset_t __force __user *) &s, sigsetsize);
 398         set_fs (old_fs);
 399         if (!ret) {
 400                 s32.sig[1] = (s.sig[0] >> 32);
 401                 s32.sig[0] = s.sig[0];
 402                 if (copy_to_user (set, &s32, sizeof(compat_sigset_t)))
 403                         return -EFAULT;
 404         }
 405         return ret;
 406 }
 407
 408 asmlinkage long
 409 sys32_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t __user *uinfo)
 410 {
 411         siginfo_t info;
 412         int ret;
 413         mm_segment_t old_fs = get_fs();
 414
 415         if (copy_siginfo_from_user32(&info, uinfo))
 416                 return -EFAULT;
 417         set_fs (KERNEL_DS);
 418         ret = sys_rt_sigqueueinfo(pid, sig, (siginfo_t __force __user *) &info);
 419         set_fs (old_fs);
 420         return ret;
 421 }
 422
 423 /*
 424  * sys32_execve() executes a new program after the asm stub has set
 425  * things up for us.  This should basically do what I want it to.
 426  */
 427 asmlinkage long sys32_execve(const char __user *name, compat_uptr_t __user *argv,
 428                              compat_uptr_t __user *envp)
 429 {
 430         struct pt_regs *regs = task_pt_regs(current);
 431         char *filename;
 432         long rc;
 433
 434         filename = getname(name);
 435         rc = PTR_ERR(filename);
 436         if (IS_ERR(filename))
 437                 return rc;
 438         rc = compat_do_execve(filename, argv, envp, regs);
 439         if (rc)
 440                 goto out;
 441         current->thread.fp_regs.fpc=0;
 442         asm volatile("sfpc %0,0" : : "d" (0));
 443         rc = regs->gprs[2];
 444 out:
 445         putname(filename);
 446         return rc;
 447 }
 448
 449 asmlinkage long sys32_pread64(unsigned int fd, char __user *ubuf,
 450                                 size_t count, u32 poshi, u32 poslo)
 451 {
 452         if ((compat_ssize_t) count < 0)
 453                 return -EINVAL;
 454         return sys_pread64(fd, ubuf, count, ((loff_t)AA(poshi) << 32) | AA(poslo));
 455 }
 456
 457 asmlinkage long sys32_pwrite64(unsigned int fd, const char __user *ubuf,
 458                                 size_t count, u32 poshi, u32 poslo)
 459 {
 460         if ((compat_ssize_t) count < 0)
 461                 return -EINVAL;
 462         return sys_pwrite64(fd, ubuf, count, ((loff_t)AA(poshi) << 32) | AA(poslo));
 463 }
 464
 465 asmlinkage compat_ssize_t sys32_readahead(int fd, u32 offhi, u32 offlo, s32 count)
 466 {
 467         return sys_readahead(fd, ((loff_t)AA(offhi) << 32) | AA(offlo), count);
 468 }
 469
 470 asmlinkage long sys32_sendfile(int out_fd, int in_fd, compat_off_t __user *offset, size_t count)
 471 {
 472         mm_segment_t old_fs = get_fs();
 473         int ret;
 474         off_t of;
 475
 476         if (offset && get_user(of, offset))
 477                 return -EFAULT;
 478
 479         set_fs(KERNEL_DS);
 480         ret = sys_sendfile(out_fd, in_fd,
 481                            offset ? (off_t __force __user *) &of : NULL, count);
 482         set_fs(old_fs);
 483
 484         if (offset && put_user(of, offset))
 485                 return -EFAULT;
 486
 487         return ret;
 488 }
 489
 490 asmlinkage long sys32_sendfile64(int out_fd, int in_fd,
 491                                 compat_loff_t __user *offset, s32 count)
 492 {
 493         mm_segment_t old_fs = get_fs();
 494         int ret;
 495         loff_t lof;
 496
 497         if (offset && get_user(lof, offset))
 498                 return -EFAULT;
 499
 500         set_fs(KERNEL_DS);
 501         ret = sys_sendfile64(out_fd, in_fd,
 502                              offset ? (loff_t __force __user *) &lof : NULL,
 503                              count);
 504         set_fs(old_fs);
 505
 506         if (offset && put_user(lof, offset))
 507                 return -EFAULT;
 508
 509         return ret;
 510 }
 511
 512 struct stat64_emu31 {
 513         unsigned long long  st_dev;
 514         unsigned int    __pad1;
 515 #define STAT64_HAS_BROKEN_ST_INO        1
 516         u32             __st_ino;
 517         unsigned int    st_mode;
 518         unsigned int    st_nlink;
 519         u32             st_uid;
 520         u32             st_gid;
 521         unsigned long long  st_rdev;
 522         unsigned int    __pad3;
 523         long            st_size;
 524         u32             st_blksize;
 525         unsigned char   __pad4[4];
 526         u32             __pad5;     /* future possible st_blocks high bits */
 527         u32             st_blocks;  /* Number 512-byte blocks allocated. */
 528         u32             st_atime;
 529         u32             __pad6;
 530         u32             st_mtime;
 531         u32             __pad7;
 532         u32             st_ctime;
 533         u32             __pad8;     /* will be high 32 bits of ctime someday */
 534         unsigned long   st_ino;
 535 };
 536
 537 static int cp_stat64(struct stat64_emu31 __user *ubuf, struct kstat *stat)
 538 {
 539         struct stat64_emu31 tmp;
 540
 541         memset(&tmp, 0, sizeof(tmp));
 542
 543         tmp.st_dev = huge_encode_dev(stat->dev);
 544         tmp.st_ino = stat->ino;
 545         tmp.__st_ino = (u32)stat->ino;
 546         tmp.st_mode = stat->mode;
 547         tmp.st_nlink = (unsigned int)stat->nlink;
 548         tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
 549         tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
 550         tmp.st_rdev = huge_encode_dev(stat->rdev);
 551         tmp.st_size = stat->size;
 552         tmp.st_blksize = (u32)stat->blksize;
 553         tmp.st_blocks = (u32)stat->blocks;
 554         tmp.st_atime = (u32)stat->atime.tv_sec;
 555         tmp.st_mtime = (u32)stat->mtime.tv_sec;
 556         tmp.st_ctime = (u32)stat->ctime.tv_sec;
 557
 558         return copy_to_user(ubuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 559 }
 560
 561 asmlinkage long sys32_stat64(const char __user * filename, struct stat64_emu31 __user * statbuf)
 562 {
 563         struct kstat stat;
 564         int ret = vfs_stat(filename, &stat);
 565         if (!ret)
 566                 ret = cp_stat64(statbuf, &stat);
 567         return ret;
 568 }
 569
 570 asmlinkage long sys32_lstat64(const char __user * filename, struct stat64_emu31 __user * statbuf)
 571 {
 572         struct kstat stat;
 573         int ret = vfs_lstat(filename, &stat);
 574         if (!ret)
 575                 ret = cp_stat64(statbuf, &stat);
 576         return ret;
 577 }
 578
 579 asmlinkage long sys32_fstat64(unsigned long fd, struct stat64_emu31 __user * statbuf)
 580 {
 581         struct kstat stat;
 582         int ret = vfs_fstat(fd, &stat);
 583         if (!ret)
 584                 ret = cp_stat64(statbuf, &stat);
 585         return ret;
 586 }
 587
 588 asmlinkage long sys32_fstatat64(unsigned int dfd, const char __user *filename,
 589                                 struct stat64_emu31 __user* statbuf, int flag)
 590 {
 591         struct kstat stat;
 592         int error;
 593
 594         error = vfs_fstatat(dfd, filename, &stat, flag);
 595         if (error)
 596                 return error;
 597         return cp_stat64(statbuf, &stat);
 598 }
 599
 600 /*
 601  * Linux/i386 didn't use to be able to handle more than
 602  * 4 system call parameters, so these system calls used a memory
 603  * block for parameter passing..
 604  */
 605
 606 struct mmap_arg_struct_emu31 {
 607         compat_ulong_t addr;
 608         compat_ulong_t len;
 609         compat_ulong_t prot;
 610         compat_ulong_t flags;
 611         compat_ulong_t fd;
 612         compat_ulong_t offset;
 613 };
 614
 615 asmlinkage unsigned long old32_mmap(struct mmap_arg_struct_emu31 __user *arg)
 616 {
 617         struct mmap_arg_struct_emu31 a;
 618
 619         if (copy_from_user(&a, arg, sizeof(a)))
 620                 return -EFAULT;
 621         if (a.offset & ~PAGE_MASK)
 622                 return -EINVAL;
 623         a.addr = (unsigned long) compat_ptr(a.addr);
 624         return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
 625                               a.offset >> PAGE_SHIFT);
 626 }
 627
 628 asmlinkage long sys32_mmap2(struct mmap_arg_struct_emu31 __user *arg)
 629 {
 630         struct mmap_arg_struct_emu31 a;
 631
 632         if (copy_from_user(&a, arg, sizeof(a)))
 633                 return -EFAULT;
 634         a.addr = (unsigned long) compat_ptr(a.addr);
 635         return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
 636 }
 637
 638 asmlinkage long sys32_read(unsigned int fd, char __user * buf, size_t count)
 639 {
 640         if ((compat_ssize_t) count < 0)
 641                 return -EINVAL;
 642
 643         return sys_read(fd, buf, count);
 644 }
 645
 646 asmlinkage long sys32_write(unsigned int fd, const char __user * buf, size_t count)
 647 {
 648         if ((compat_ssize_t) count < 0)
 649                 return -EINVAL;
 650
 651         return sys_write(fd, buf, count);
 652 }
 653
 654 /*
 655  * 31 bit emulation wrapper functions for sys_fadvise64/fadvise64_64.
 656  * These need to rewrite the advise values for POSIX_FADV_{DONTNEED,NOREUSE}
 657  * because the 31 bit values differ from the 64 bit values.
 658  */
 659
 660 asmlinkage long
 661 sys32_fadvise64(int fd, loff_t offset, size_t len, int advise)
 662 {
 663         if (advise == 4)
 664                 advise = POSIX_FADV_DONTNEED;
 665         else if (advise == 5)
 666                 advise = POSIX_FADV_NOREUSE;
 667         return sys_fadvise64(fd, offset, len, advise);
 668 }
 669
 670 struct fadvise64_64_args {
 671         int fd;
 672         long long offset;
 673         long long len;
 674         int advice;
 675 };
 676
 677 asmlinkage long
 678 sys32_fadvise64_64(struct fadvise64_64_args __user *args)
 679 {
 680         struct fadvise64_64_args a;
 681
 682         if ( copy_from_user(&a, args, sizeof(a)) )
 683                 return -EFAULT;
 684         if (a.advice == 4)
 685                 a.advice = POSIX_FADV_DONTNEED;
 686         else if (a.advice == 5)
 687                 a.advice = POSIX_FADV_NOREUSE;
 688         return sys_fadvise64_64(a.fd, a.offset, a.len, a.advice);
 689 }