sysdeps/unix/sysv/linux/fcntl.c

   1 /* Linux fcntl syscall implementation.
   2    Copyright (C) 2000-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <fcntl.h>
  20 #include <stdarg.h>
  21 #include <errno.h>
  22 #include <sysdep-cancel.h>
  23
  24 #ifndef __OFF_T_MATCHES_OFF64_T
  25
  26 # ifndef FCNTL_ADJUST_CMD
  27 #  define FCNTL_ADJUST_CMD(__cmd) __cmd
  28 # endif
  29
  30 int
  31 __libc_fcntl (int fd, int cmd, ...)
  32 {
  33   va_list ap;
  34   void *arg;
  35
  36   va_start (ap, cmd);
  37   arg = va_arg (ap, void *);
  38   va_end (ap);
  39
  40   cmd = FCNTL_ADJUST_CMD (cmd);
  41
  42   switch (cmd)
  43     {
  44       case F_SETLKW:
  45       case F_SETLKW64:
  46         return SYSCALL_CANCEL (fcntl64, fd, cmd, arg);
  47       case F_OFD_SETLKW:
  48         {
  49           struct flock *flk = (struct flock *) arg;
  50           struct flock64 flk64 =
  51           {
  52             .l_type = flk->l_type,
  53             .l_whence = flk->l_whence,
  54             .l_start = flk->l_start,
  55             .l_len = flk->l_len,
  56             .l_pid = flk->l_pid
  57           };
  58           return SYSCALL_CANCEL (fcntl64, fd, cmd, &flk64);
  59         }
  60       case F_OFD_GETLK:
  61       case F_OFD_SETLK:
  62         {
  63           struct flock *flk = (struct flock *) arg;
  64           struct flock64 flk64 =
  65           {
  66             .l_type = flk->l_type,
  67             .l_whence = flk->l_whence,
  68             .l_start = flk->l_start,
  69             .l_len = flk->l_len,
  70             .l_pid = flk->l_pid
  71           };
  72           int ret = INLINE_SYSCALL_CALL (fcntl64, fd, cmd, &flk64);
  73           if (ret == -1)
  74             return -1;
  75           if ((off_t) flk64.l_start != flk64.l_start
  76               || (off_t) flk64.l_len != flk64.l_len)
  77             {
  78               __set_errno (EOVERFLOW);
  79               return -1;
  80             }
  81           flk->l_type = flk64.l_type;
  82           flk->l_whence = flk64.l_whence;
  83           flk->l_start = flk64.l_start;
  84           flk->l_len = flk64.l_len;
  85           flk->l_pid = flk64.l_pid;
  86           return ret;
  87         }
  88       /* Since only F_SETLKW{64}/F_OLD_SETLK are cancellation entrypoints and
  89          only OFD locks require LFS handling, all others flags are handled
  90          unmodified by calling __NR_fcntl64.  */
  91       default:
  92         return __fcntl64_nocancel_adjusted (fd, cmd, arg);
  93     }
  94 }
  95 libc_hidden_def (__libc_fcntl)
  96
  97 weak_alias (__libc_fcntl, __fcntl)
  98 libc_hidden_weak (__fcntl)
  99
 100 # include <shlib-compat.h>
 101 # if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_28)
 102 int
 103 __old_libc_fcntl64 (int fd, int cmd, ...)
 104 {
 105   va_list ap;
 106   void *arg;
 107
 108   va_start (ap, cmd);
 109   arg = va_arg (ap, void *);
 110   va_end (ap);
 111
 112   /* Previous versions called __NR_fcntl64 for fcntl (which did not handle
 113      OFD locks in LFS mode).  */
 114   return __libc_fcntl64 (fd, cmd, arg);
 115 }
 116 compat_symbol (libc, __old_libc_fcntl64, fcntl, GLIBC_2_0);
 117 versioned_symbol (libc, __libc_fcntl, fcntl, GLIBC_2_28);
 118 # else
 119 weak_alias (__libc_fcntl, fcntl)
 120 # endif
 121
 122 #endif /* __OFF_T_MATCHES_OFF64_T  */