linux-kernel - Re: return negative number for unsigned long function in kernel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 06 Mar 2007 20:05:38 +0100
From:	Andreas Schwab <schwab@...e.de>
To:	"Chen, Dongliang" <Chen.D@...-t.com>
Cc:	<linux-kernel@...r.kernel.org>
Subject: Re: return negative number for unsigned long function in kernel

"Chen, Dongliang" <Chen.D@...-t.com> writes:

> There are lots of functions in the Linux kernel that are declared as
> unsigned long, but the return value is negative integer while error
> occurred. An example of these functions is do_mmap_pgoff in mm/mmap.c,
> which is defined as:
>
> unsigned long do_mmap_pgoff(....)
>
> In this function, it returns -ENODEV, -EPERM, -ENOMEM, -EINVAL, -EAGAIN,
> -EACCESS depends on the error type. My question is how should the caller
> perform error check based on the return value? 

The return value is directly passed to user space (it's the guts of the
mmap syscall).  The glibc wrapper transforms it appropriately so that
errno is set and -1 is returned if there is an error.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@...e.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/