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 <sys/syscall.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
  74 static ssize_t __fake_pread_write(int fd, void *buf,
  75                 size_t count, off_t offset, int do_pwrite)
  76 {
  77         int save_errno;
  78         ssize_t result;
  79         off_t old_offset;
  80
  81         /* Since we must not change the file pointer preserve the
  82          * value so that we can restore it later.  */
  83         if ((old_offset=lseek(fd, 0, SEEK_CUR)) == (off_t) -1)
  84                 return -1;
  85
  86         /* Set to wanted position.  */
  87         if (lseek (fd, offset, SEEK_SET) == (off_t) -1)
  88                 return -1;
  89
  90         if (do_pwrite==1) {
  91                 /* Write the data.  */
  92                 result = write(fd, buf, count);
  93         } else {
  94                 /* Read the data.  */
  95                 result = read(fd, buf, count);
  96         }
  97
  98         /* Now we have to restore the position.  If this fails we
  99          * have to return this as an error.  */
 100         save_errno = errno;
 101         if (lseek(fd, old_offset, SEEK_SET) == (off_t) -1)
 102         {
 103                 if (result == -1)
 104                         __set_errno(save_errno);
 105                 return -1;
 106         }
 107         __set_errno(save_errno);
 108         return(result);
 109 }
 110
 111 # ifdef __UCLIBC_HAS_LFS__
 112 libc_hidden_proto(lseek64)
 113
 114 static ssize_t __fake_pread_write64(int fd, void *buf,
 115                 size_t count, off64_t offset, int do_pwrite)
 116 {
 117         int save_errno;
 118         ssize_t result;
 119         off64_t old_offset;
 120
 121         /* Since we must not change the file pointer preserve the
 122          * value so that we can restore it later.  */
 123         if ((old_offset=lseek64(fd, 0, SEEK_CUR)) == (off64_t) -1)
 124                 return -1;
 125
 126         /* Set to wanted position.  */
 127         if (lseek64(fd, offset, SEEK_SET) == (off64_t) -1)
 128                 return -1;
 129
 130         if (do_pwrite==1) {
 131                 /* Write the data.  */
 132                 result = write(fd, buf, count);
 133         } else {
 134                 /* Read the data.  */
 135                 result = read(fd, buf, count);
 136         }
 137
 138         /* Now we have to restore the position. */
 139         save_errno = errno;
 140         if (lseek64 (fd, old_offset, SEEK_SET) == (off64_t) -1) {
 141                 if (result == -1)
 142                         __set_errno (save_errno);
 143                 return -1;
 144         }
 145         __set_errno (save_errno);
 146         return result;
 147 }
 148 # endif /* __UCLIBC_HAS_LFS__  */
 149 #endif /*  ! defined __NR_pread || ! defined __NR_pwrite */
 150
 151 #ifndef __NR_pread
 152 ssize_t __libc_pread(int fd, void *buf, size_t count, off_t offset)
 153 {
 154         return(__fake_pread_write(fd, buf, count, offset, 0));
 155 }
 156 weak_alias(__libc_pread,pread)
 157
 158 # ifdef __UCLIBC_HAS_LFS__
 159 ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset)
 160 {
 161         return(__fake_pread_write64(fd, buf, count, offset, 0));
 162 }
 163 weak_alias(__libc_pread64,pread64)
 164 # endif /* __UCLIBC_HAS_LFS__  */
 165 #endif /* ! __NR_pread */
 166
 167
 168 #ifndef __NR_pwrite
 169 ssize_t __libc_pwrite(int fd, const void *buf, size_t count, off_t offset)
 170 {
 171         return(__fake_pread_write(fd, (void*)buf, count, offset, 1));
 172 }
 173 weak_alias(__libc_pwrite,pwrite)
 174
 175 # ifdef __UCLIBC_HAS_LFS__
 176 ssize_t __libc_pwrite64(int fd, const void *buf, size_t count, off64_t offset)
 177 {
 178         return(__fake_pread_write64(fd, (void*)buf, count, offset, 1));
 179 }
 180 weak_alias(__libc_pwrite64,pwrite64)
 181 # endif /* __UCLIBC_HAS_LFS__  */
 182 #endif /* ! __NR_pwrite */