Return-Path: Received: from mail-qt0-f194.google.com ([209.85.216.194]:35250 "EHLO mail-qt0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754706AbcLOHm7 (ORCPT ); Thu, 15 Dec 2016 02:42:59 -0500 Received: by mail-qt0-f194.google.com with SMTP id m48so5870707qta.2 for ; Wed, 14 Dec 2016 23:42:58 -0800 (PST) From: Jia He To: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "Eric W. Biederman" , Andrew Morton , Dmitry Torokhov , Serge Hallyn , "David S. Miller" , Alexey Dobriyan , Subash Abhinov Kasiviswanathan , Arnaldo Carvalho de Melo , Al Viro , Mel Gorman , Kees Cook , Hugh Dickins , Daniel Bristot de Oliveira , Daniel Cashman , Arnd Bergmann , "J. Bruce Fields" , Jeff Layton , Trond Myklebust , Anna Schumaker , Jia He Subject: [PATCH v5 1/2] sysctl: introduce new proc handler proc_dobool Date: Thu, 15 Dec 2016 15:24:20 +0800 Message-Id: <1481786661-973-2-git-send-email-hejianet@gmail.com> In-Reply-To: <1481786661-973-1-git-send-email-hejianet@gmail.com> References: <1481786661-973-1-git-send-email-hejianet@gmail.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: This is to let bool variable could be correctly displayed in big/little endian sysctl procfs. sizeof(bool) is arch dependent, proc_dobool should work in all arches. Suggested-by: Pan Xinhui Signed-off-by: Jia He --- include/linux/sysctl.h | 2 ++ kernel/sysctl.c | 41 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+) diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index adf4e51..255a9c7 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -41,6 +41,8 @@ typedef int proc_handler (struct ctl_table *ctl, int write, extern int proc_dostring(struct ctl_table *, int, void __user *, size_t *, loff_t *); +extern int proc_dobool(struct ctl_table *, int, + void __user *, size_t *, loff_t *); extern int proc_dointvec(struct ctl_table *, int, void __user *, size_t *, loff_t *); extern int proc_douintvec(struct ctl_table *, int, diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 706309f..c4bec65 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2112,6 +2112,20 @@ static int proc_put_char(void __user **buf, size_t *size, char c) return 0; } +static int do_proc_dobool_conv(bool *negp, unsigned long *lvalp, + int *valp, + int write, void *data) +{ + if (write) + *(bool *)valp = *lvalp; + else { + int val = *(bool *)valp; + + *lvalp = (unsigned long)val; + } + return 0; +} + static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp, int *valp, int write, void *data) @@ -2258,6 +2272,26 @@ static int do_proc_dointvec(struct ctl_table *table, int write, } /** + * proc_dobool - read/write a bool + * @table: the sysctl table + * @write: %TRUE if this is a write to the sysctl file + * @buffer: the user buffer + * @lenp: the size of the user buffer + * @ppos: file position + * + * Reads/writes up to table->maxlen/sizeof(unsigned int) integer + * values from/to the user buffer, treated as an ASCII string. + * + * Returns 0 on success. + */ +int proc_dobool(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + return do_proc_dointvec(table, write, buffer, lenp, ppos, + do_proc_dobool_conv, NULL); +} + +/** * proc_dointvec - read a vector of integers * @table: the sysctl table * @write: %TRUE if this is a write to the sysctl file @@ -2885,6 +2919,12 @@ int proc_dostring(struct ctl_table *table, int write, return -ENOSYS; } +int proc_dobool(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + return -ENOSYS; +} + int proc_dointvec(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { @@ -2941,6 +2981,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write, * No sense putting this after each symbol definition, twice, * exception granted :-) */ +EXPORT_SYMBOL(proc_dobool); EXPORT_SYMBOL(proc_dointvec); EXPORT_SYMBOL(proc_douintvec); EXPORT_SYMBOL(proc_dointvec_jiffies); -- 2.5.5