/* vi: set sw=4 ts=4: * * Copyright (C) 2002 by Erik Andersen <andersen@uclibc.org> * Based in part on the files * ./sysdeps/unix/sysv/linux/pwrite.c, * ./sysdeps/unix/sysv/linux/pread.c, * sysdeps/posix/pread.c * sysdeps/posix/pwrite.c * from GNU libc 2.2.5, but reworked considerably... * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU Library General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at your * option) any later version. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License * for more details. * * You should have received a copy of the GNU Library General Public License * along with this program; if not, write to the Free Software Foundation, * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #define _GNU_SOURCE #define _LARGEFILE64_SOURCE #include <features.h> #undef __OPTIMIZE__ /* We absolutely do _NOT_ want interfaces silently * * * renamed under us or very bad things will happen... */ #ifdef __USE_FILE_OFFSET64 # undef __USE_FILE_OFFSET64 #endif #include <errno.h> #include <sys/types.h> #include <sys/syscall.h> #include <unistd.h> #include <stdint.h> #ifdef __NR_pread #define __NR___syscall_pread __NR_pread static inline _syscall5(ssize_t, __syscall_pread, int, fd, void *, buf, size_t, count, off_t, offset_hi, off_t, offset_lo); ssize_t __libc_pread(int fd, void *buf, size_t count, off_t offset) { return(__syscall_pread(fd,buf,count,__LONG_LONG_PAIR (offset >> 31, offset))); } weak_alias (__libc_pread, pread) #if defined __UCLIBC_HAS_LFS__ ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset) { uint32_t low = offset & 0xffffffff; uint32_t high = offset >> 32; return(__syscall_pread(fd, buf, count, __LONG_LONG_PAIR (high, low))); } weak_alias (__libc_pread64, pread64) #endif /* __UCLIBC_HAS_LFS__ */ #endif /* __NR_pread */ #ifdef __NR_pwrite #define __NR___syscall_pwrite __NR_pwrite static inline _syscall5(ssize_t, __syscall_pwrite, int, fd, const void *, buf, size_t, count, off_t, offset_hi, off_t, offset_lo); ssize_t __libc_pwrite(int fd, const void *buf, size_t count, off_t offset) { return(__syscall_pwrite(fd,buf,count,__LONG_LONG_PAIR (offset >> 31, offset))); } weak_alias (__libc_pwrite, pwrite) #if defined __UCLIBC_HAS_LFS__ ssize_t __libc_pwrite64(int fd, const void *buf, size_t count, off64_t offset) { uint32_t low = offset & 0xffffffff; uint32_t high = offset >> 32; return(__syscall_pwrite(fd, buf, count, __LONG_LONG_PAIR (high, low))); } weak_alias (__libc_pwrite64, pwrite64) #endif /* __UCLIBC_HAS_LFS__ */ #endif /* __NR_pwrite */ #if ! defined __NR_pread || ! defined __NR_pwrite static ssize_t __fake_pread_write(int fd, void *buf, size_t count, off_t offset, int do_pwrite) { int save_errno; ssize_t result; off_t old_offset; /* Since we must not change the file pointer preserve the * value so that we can restore it later. */ if ((old_offset=lseek(fd, 0, SEEK_CUR)) == (off_t) -1) return -1; /* Set to wanted position. */ if (lseek (fd, offset, SEEK_SET) == (off_t) -1) return -1; if (do_pwrite==1) { /* Write the data. */ result = write(fd, buf, count); } else { /* Read the data. */ result = read(fd, buf, count); } /* Now we have to restore the position. If this fails we * have to return this as an error. */ save_errno = errno; if (lseek(fd, old_offset, SEEK_SET) == (off_t) -1) { if (result == -1) __set_errno(save_errno); return -1; } __set_errno(save_errno); return(result); } #if defined __UCLIBC_HAS_LFS__ static ssize_t __fake_pread_write64(int fd, void *buf, size_t count, off64_t offset, int do_pwrite) { int save_errno; ssize_t result; off64_t old_offset; /* Since we must not change the file pointer preserve the * value so that we can restore it later. */ if ((old_offset=lseek64(fd, 0, SEEK_CUR)) == (off64_t) -1) return -1; /* Set to wanted position. */ if (lseek64(fd, offset, SEEK_SET) == (off64_t) -1) return -1; if (do_pwrite==1) { /* Write the data. */ result = write(fd, buf, count); } else { /* Read the data. */ result = read(fd, buf, count); } /* Now we have to restore the position. */ save_errno = errno; if (lseek64 (fd, old_offset, SEEK_SET) == (off64_t) -1) { if (result == -1) __set_errno (save_errno); return -1; } __set_errno (save_errno); return result; } #endif /* __UCLIBC_HAS_LFS__ */ #endif /* ! defined __NR_pread || ! defined __NR_pwrite */ #ifndef __NR_pread ssize_t __libc_pread(int fd, void *buf, size_t count, off_t offset) { return(__fake_pread_write(fd, buf, count, offset, 0)); } weak_alias (__libc_pread, pread) #if defined __UCLIBC_HAS_LFS__ ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset) { return(__fake_pread_write64(fd, buf, count, offset, 0)); } weak_alias (__libc_pread64, pread64) #endif /* __UCLIBC_HAS_LFS__ */ #endif /* ! __NR_pread */ #ifndef __NR_pwrite ssize_t __libc_pwrite(int fd, const void *buf, size_t count, off_t offset) { return(__fake_pread_write(fd, buf, count, offset, 1)); } weak_alias (__libc_pwrite, pwrite) #if defined __UCLIBC_HAS_LFS__ ssize_t __libc_pwrite64(int fd, const void *buf, size_t count, off64_t offset) { return(__fake_pread_write64(fd, (void*)buf, count, offset, 1)); } weak_alias (__libc_pwrite64, pwrite64) #endif /* __UCLIBC_HAS_LFS__ */ #endif /* ! __NR_pwrite */