/* vi: set sw=4 ts=4: */ /* * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org> * * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball. */ /* * 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... */ #include <sys/syscall.h> #include <unistd.h> #include <stdint.h> #include <endian.h> extern __typeof(pread) __libc_pread; extern __typeof(pwrite) __libc_pwrite; #ifdef __UCLIBC_HAS_LFS__ extern __typeof(pread64) __libc_pread64; extern __typeof(pwrite64) __libc_pwrite64; #endif #include <bits/kernel_types.h> #ifdef __NR_pread # define __NR___syscall_pread __NR_pread /* On Xtensa, 64-bit values are aligned in even/odd register pairs. */ static __inline__ _syscall6(ssize_t, __syscall_pread, int, fd, void *, buf, size_t, count, int, pad, 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, 0, __LONG_LONG_PAIR(offset >> 31, offset)); } weak_alias(__libc_pread,pread) # ifdef __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, 0, __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 /* On Xtensa, 64-bit values are aligned in even/odd register pairs. */ static __inline__ _syscall6(ssize_t, __syscall_pwrite, int, fd, const void *, buf, size_t, count, int, pad, 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, 0, __LONG_LONG_PAIR(offset >> 31, offset)); } weak_alias(__libc_pwrite,pwrite) # ifdef __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, 0, __LONG_LONG_PAIR(high, low)); } weak_alias(__libc_pwrite64,pwrite64) # endif /* __UCLIBC_HAS_LFS__ */ #endif /* __NR_pwrite */ #if ! defined __NR_pread || ! defined __NR_pwrite /* libc_hidden_proto(read) */ /* libc_hidden_proto(write) */ /* libc_hidden_proto(lseek) */ 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); } # ifdef __UCLIBC_HAS_LFS__ /* libc_hidden_proto(lseek64) */ 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) # ifdef __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) { /* we won't actually be modifying the buffer, *just cast it to get rid of warnings */ return __fake_pread_write(fd, (void*)buf, count, offset, 1); } weak_alias(__libc_pwrite,pwrite) # ifdef __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 */