From 17c362cce61538cf64beb33c524c21344be090bc Mon Sep 17 00:00:00 2001 From: Eric Andersen Date: Mon, 15 Jul 2002 09:59:46 +0000 Subject: Rework pread and pwrite support so it should actually work. Add support for pread64 and pwrite64. Fixup llseek a bit. -Erik --- libc/sysdeps/linux/common/Makefile | 3 +- libc/sysdeps/linux/common/pread_write.c | 213 ++++++++++++++++++++++++++++++++ libc/sysdeps/linux/common/syscalls.c | 36 +----- 3 files changed, 219 insertions(+), 33 deletions(-) create mode 100644 libc/sysdeps/linux/common/pread_write.c (limited to 'libc/sysdeps/linux') diff --git a/libc/sysdeps/linux/common/Makefile b/libc/sysdeps/linux/common/Makefile index a7a254cc5..3e6a5136d 100644 --- a/libc/sysdeps/linux/common/Makefile +++ b/libc/sysdeps/linux/common/Makefile @@ -33,7 +33,8 @@ CSRC= waitpid.c statfix.c getdnnm.c gethstnm.c getcwd.c \ mkfifo.c setegid.c wait.c getpagesize.c seteuid.c \ wait3.c setpgrp.c getdtablesize.c create_module.c ptrace.c \ cmsg_nxthdr.c statfix64.c longjmp.c open64.c ftruncate64.c \ - truncate64.c getrlimit64.c setrlimit64.c creat64.c mmap64.c + truncate64.c getrlimit64.c setrlimit64.c creat64.c mmap64.c \ + pread_write.c ifneq ($(strip $(EXCLUDE_BRK)),true) CSRC+=sbrk.c endif diff --git a/libc/sysdeps/linux/common/pread_write.c b/libc/sysdeps/linux/common/pread_write.c new file mode 100644 index 000000000..319de5af1 --- /dev/null +++ b/libc/sysdeps/linux/common/pread_write.c @@ -0,0 +1,213 @@ +/* vi: set sw=4 ts=4: + * + * Copyright (C) 2002 by Erik Andersen + * 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 + */ + +#include +#if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS != 64 +#undef _FILE_OFFSET_BITS +#define _FILE_OFFSET_BITS 64 +#endif +#ifndef __USE_LARGEFILE64 +# define __USE_LARGEFILE64 1 +#endif +/* 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 +#include +#include +#define _XOPEN_SOURCE 500 +#include + +#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); +#endif + +#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); +#endif + + +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; + 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 (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); +} + +ssize_t __libc_pread(int fd, void *buf, size_t count, __off_t offset) +{ +#ifndef __NR_pread + return(__fake_pread_write(fd, buf, count, offset, 0)); +#else + ssize_t result; + + /* First try the syscall. */ + result = __syscall_pread(fd, buf, count, __LONG_LONG_PAIR(0, offset)); + + /* Bummer. Syscall failed or is missing. Fake it */ + if (result == -1 && errno == ENOSYS) { + result = __fake_pread_write(fd, buf, count, offset, 0); + } +#endif + return result; +} +weak_alias (__libc_pread, pread) + +ssize_t __libc_pwrite(int fd, const void *buf, size_t count, __off_t offset) +{ +#ifndef __NR_pwrite + return(__fake_pread_write(fd, buf, count, offset, 1)); +#else + ssize_t result; + + /* First try the syscall. */ + result = __syscall_pwrite(fd, buf, count, __LONG_LONG_PAIR(0, offset)); + + /* Bummer. Syscall failed or is missing. Fake it */ + if (result == -1 && errno == ENOSYS) { + result = __fake_pread_write(fd, (void*)buf, count, offset, 1); + } +#endif + return result; +} +weak_alias (__libc_pwrite, pwrite) + + + + +#if defined __UCLIBC_HAVE_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; +} + +ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset) +{ +#ifndef __NR_pread + return(__fake_pread_write64(fd, buf, count, offset, 0)); +#else + ssize_t result; + /* First try the syscall. */ + result = __syscall_pread(fd, buf, count, + __LONG_LONG_PAIR((__off_t) (offset >> 32), (__off_t) (offset & 0xffffffff))); + + /* Bummer. Syscall failed or is missing. Fake it */ + if (result == -1 && errno == ENOSYS) { + result = __fake_pread_write64(fd, buf, count, offset, 0); + } + return result; +#endif +} +weak_alias (__libc_pread64, pread64) + +ssize_t __libc_pwrite64(int fd, const void *buf, size_t count, off64_t offset) +{ +#ifndef __NR_pwrite + return(__fake_pread_write64(fd, (void*)buf, count, offset, 1)); +#else + ssize_t result; + + /* First try the syscall. */ + result = __syscall_pwrite(fd, buf, count, + __LONG_LONG_PAIR((__off_t) (offset >> 32), (__off_t) (offset & 0xffffffff))); + + /* Bummer. Syscall failed or is missing. Fake it */ + if (result == -1 && errno == ENOSYS) { + result = __fake_pread_write64(fd, (void*)buf, count, offset, 1); + } + return result; +#endif +} +weak_alias (__libc_pwrite64, pwrite64) + +#endif + diff --git a/libc/sysdeps/linux/common/syscalls.c b/libc/sysdeps/linux/common/syscalls.c index 318bbfbb3..1b63c3dba 100644 --- a/libc/sysdeps/linux/common/syscalls.c +++ b/libc/sysdeps/linux/common/syscalls.c @@ -1254,8 +1254,8 @@ __loff_t __libc_lseek64(int fd, __loff_t offset, int whence) int ret; __loff_t result; - ret = _llseek(fd, (__off_t) (offset >> 32), - (__off_t) (offset & 0xffffffff), &result, whence); + ret = _llseek(fd, __LONG_LONG_PAIR((__off_t) (offset >> 32), + (__off_t) (offset & 0xffffffff)), &result, whence); return ret ? (__loff_t) ret : result; } @@ -1574,38 +1574,10 @@ int sigsuspend (const sigset_t *mask) #endif //#define __NR_pread 180 -#ifdef L___libc_pread -#ifdef __NR_pread -#define _XOPEN_SOURCE 500 -#include -#define __NR___libc_pread __NR_pread -_syscall4(ssize_t, __libc_pread, int, fd, void *, buf, size_t, count, __off_t, offset); -weak_alias (__libc_pread, pread) -#else -ssize_t pread(int fd, void *buf, size_t count, off_t offset) -{ - __set_errno(ENOSYS); - return -1; -} -#endif -#endif +// See pread_write.c //#define __NR_pwrite 181 -#ifdef L___libc_pwrite -#ifdef __NR_pwrite -#define _XOPEN_SOURCE 500 -#include -#define __NR___libc_pwrite __NR_pwrite -_syscall4(ssize_t, __libc_pwrite, int, fd, const void *, buf, size_t, count, __off_t, offset); -weak_alias (__libc_pwrite, pwrite) -#else -ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset) -{ - __set_errno(ENOSYS); - return -1; -} -#endif -#endif +// See pread_write.c //#define __NR_chown 182 #ifdef L_chown -- cgit v1.2.3