On Sun Oct 20, 2002 at 05:31:47AM +0100, Matthew Wilcox wrote:
>
> *sigh*. i hate this kind of bullshit. please, don't anyone ever try
> to pass 64-bit args through the syscall interface again.
I agree it can be a pain.
[-----------snip-------------]
> -asmlinkage ssize_t sys_pread64(unsigned int fd, char *buf,
> - size_t count, loff_t pos)
> +#ifdef __BIG_ENDIAN
> +asmlinkage ssize_t sys_pread64(unsigned int fd, char *buf, size_t count,
> + unsigned int high, unsigned int low)
> +#else
> +asmlinkage ssize_t sys_pread64(unsigned int fd, char *buf, size_t count,
> + unsigned int low, unsigned int high)
> +#endif
Nonono. Please see __LONG_LONG_PAIR in /usr/include/endian.h.
Your user space code should be doing something like this:
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((off_t)0,offset)));
}
ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset)
{
return(__syscall_pread(fd, buf, count,
__LONG_LONG_PAIR((off_t)(offset>>32),
(off_t)(offset&0xffffffff))));
}
Your patch is going to break GNU libc, uClibc, and anyone else in
userspace that is doing pread and pread64 correctly....
-Erik
-- Erik B. Andersen http://codepoet-consulting.com/ --This message was written using 73% post-consumer electrons-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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