libc/sysdeps/linux/powerpc/pread_write.c

   1 /* vi: set sw=4 ts=4:
   2  *
   3  * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
   4  *
   5  * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
   6  */
   7 /* Based in part on the files
   8  *              ./sysdeps/unix/sysv/linux/pwrite.c,
   9  *              ./sysdeps/unix/sysv/linux/pread.c,
  10  *              sysdeps/posix/pread.c
  11  *              sysdeps/posix/pwrite.c
  12  * from GNU libc 2.2.5, but reworked considerably...
  13  */
  14
  15 #include "../common/syscalls.h"
  16 #include <unistd.h>
  17
  18 #ifndef __UCLIBC_HAS_LFS__
  19 # define off64_t off_t
  20 #endif
  21
  22 #ifdef __NR_pread
  23 extern __typeof(pread) __libc_pread;
  24 # define __NR___syscall_pread __NR_pread
  25 static inline _syscall4(ssize_t, __syscall_pread, int, fd,
  26                 void *, buf, size_t, count, off64_t, offset);
  27
  28 ssize_t __libc_pread(int fd, void *buf, size_t count, off_t offset)
  29 {
  30         return(__syscall_pread(fd, buf, count, (off64_t)offset));
  31 }
  32 weak_alias(__libc_pread,pread)
  33
  34 # ifdef __UCLIBC_HAS_LFS__
  35 extern __typeof(pread64) __libc_pread64;
  36 ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset)
  37 {
  38         return(__syscall_pread(fd, buf, count, offset));
  39 }
  40 weak_alias(__libc_pread64,pread64)
  41 # endif /* __UCLIBC_HAS_LFS__  */
  42 #endif /* __NR_pread */
  43
  44
  45 #ifdef __NR_pwrite
  46 extern __typeof(pwrite) __libc_pwrite;
  47 # define __NR___syscall_pwrite __NR_pwrite
  48 static inline _syscall4(ssize_t, __syscall_pwrite, int, fd,
  49                 const void *, buf, size_t, count, off64_t, offset);
  50
  51 ssize_t __libc_pwrite(int fd, const void *buf, size_t count, off_t offset)
  52 {
  53         return(__syscall_pwrite(fd, buf, count, (off64_t)offset));
  54 }
  55 weak_alias(__libc_pwrite,pwrite)
  56
  57 # ifdef __UCLIBC_HAS_LFS__
  58 extern __typeof(pwrite64) __libc_pwrite64;
  59 ssize_t __libc_pwrite64(int fd, const void *buf, size_t count, off64_t offset)
  60 {
  61         return(__syscall_pwrite(fd, buf, count, offset));
  62 }
  63 weak_alias(__libc_pwrite64,pwrite64)
  64 # endif /* __UCLIBC_HAS_LFS__  */
  65 #endif /* __NR_pwrite */
  66
  67
  68
  69 #if ! defined __NR_pread || ! defined __NR_pwrite
  70 libc_hidden_proto(read)
  71 libc_hidden_proto(write)
  72 libc_hidden_proto(lseek)
  73 libc_hidden_proto(lseek64)
  74
  75 static ssize_t __fake_pread_write(int fd, void *buf,
  76                 size_t count, off_t offset, int do_pwrite)
  77 {
  78         int save_errno;
  79         ssize_t result;
  80         off_t old_offset;
  81
  82         /* Since we must not change the file pointer preserve the
  83          * value so that we can restore it later.  */
  84         if ((old_offset=lseek(fd, 0, SEEK_CUR)) == (off_t) -1)
  85                 return -1;
  86
  87         /* Set to wanted position.  */
  88         if (lseek (fd, offset, SEEK_SET) == (off_t) -1)
  89                 return -1;
  90
  91         if (do_pwrite==1) {
  92                 /* Write the data.  */
  93                 result = write(fd, buf, count);
  94         } else {
  95                 /* Read the data.  */
  96                 result = read(fd, buf, count);
  97         }
  98
  99         /* Now we have to restore the position.  If this fails we
 100          * have to return this as an error.  */
 101         save_errno = errno;
 102         if (lseek(fd, old_offset, SEEK_SET) == (off_t) -1)
 103         {
 104                 if (result == -1)
 105                         __set_errno(save_errno);
 106                 return -1;
 107         }
 108         __set_errno(save_errno);
 109         return(result);
 110 }
 111
 112 # ifdef __UCLIBC_HAS_LFS__
 113 static ssize_t __fake_pread_write64(int fd, void *buf,
 114                 size_t count, off64_t offset, int do_pwrite)
 115 {
 116         int save_errno;
 117         ssize_t result;
 118         off64_t old_offset;
 119
 120         /* Since we must not change the file pointer preserve the
 121          * value so that we can restore it later.  */
 122         if ((old_offset=lseek64(fd, 0, SEEK_CUR)) == (off64_t) -1)
 123                 return -1;
 124
 125         /* Set to wanted position.  */
 126         if (lseek64(fd, offset, SEEK_SET) == (off64_t) -1)
 127                 return -1;
 128
 129         if (do_pwrite==1) {
 130                 /* Write the data.  */
 131                 result = write(fd, buf, count);
 132         } else {
 133                 /* Read the data.  */
 134                 result = read(fd, buf, count);
 135         }
 136
 137         /* Now we have to restore the position. */
 138         save_errno = errno;
 139         if (lseek64 (fd, old_offset, SEEK_SET) == (off64_t) -1) {
 140                 if (result == -1)
 141                         __set_errno (save_errno);
 142                 return -1;
 143         }
 144         __set_errno (save_errno);
 145         return result;
 146 }
 147 # endif /* __UCLIBC_HAS_LFS__  */
 148 #endif /*  ! defined __NR_pread || ! defined __NR_pwrite */
 149
 150 #ifndef __NR_pread
 151 ssize_t __libc_pread(int fd, void *buf, size_t count, off_t offset)
 152 {
 153         return(__fake_pread_write(fd, buf, count, offset, 0));
 154 }
 155 weak_alias(__libc_pread,pread)
 156
 157 # ifdef __UCLIBC_HAS_LFS__
 158 ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset)
 159 {
 160         return(__fake_pread_write64(fd, buf, count, offset, 0));
 161 }
 162 weak_alias(__libc_pread64,pread64)
 163 # endif /* __UCLIBC_HAS_LFS__  */
 164 #endif /* ! __NR_pread */
 165
 166
 167 #ifndef __NR_pwrite
 168 ssize_t __libc_pwrite(int fd, const void *buf, size_t count, off_t offset)
 169 {
 170         return(__fake_pread_write(fd, buf, count, offset, 1));
 171 }
 172 weak_alias(__libc_pwrite,pwrite)
 173
 174 # ifdef __UCLIBC_HAS_LFS__
 175 ssize_t __libc_pwrite64(int fd, const void *buf, size_t count, off64_t offset)
 176 {
 177         return(__fake_pread_write64(fd, (void*)buf, count, offset, 1));
 178 }
 179 weak_alias(__libc_pwrite64,pwrite64)
 180 # endif /* __UCLIBC_HAS_LFS__  */
 181 #endif /* ! __NR_pwrite */