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![Eric W. Biederman](/assets/img/avatar_default.png)
The semantic effect of insert_at_head is that it would allow new registered sysctl entries to override existing sysctl entries of the same name. Which is pain for caching and the proc interface never implemented. I have done an audit and discovered that none of the current users of register_sysctl care as (excpet for directories) they do not register duplicate sysctl entries. So this patch simply removes the support for overriding existing entries in the sys_sysctl interface since no one uses it or cares and it makes future enhancments harder. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Andi Kleen <ak@muc.de> Cc: Jens Axboe <axboe@kernel.dk> Cc: Corey Minyard <minyard@acm.org> Cc: Neil Brown <neilb@suse.de> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Jan Kara <jack@ucw.cz> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: David Chinner <dgc@sgi.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Patrick McHardy <kaber@trash.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
146 lines
3.4 KiB
C
146 lines
3.4 KiB
C
/*
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* Copyright (C) 2007
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*
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* Author: Eric Biederman <ebiederm@xmision.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*/
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#include <linux/module.h>
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#include <linux/uts.h>
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#include <linux/utsname.h>
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#include <linux/version.h>
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#include <linux/sysctl.h>
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static void *get_uts(ctl_table *table, int write)
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{
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char *which = table->data;
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#ifdef CONFIG_UTS_NS
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struct uts_namespace *uts_ns = current->nsproxy->uts_ns;
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which = (which - (char *)&init_uts_ns) + (char *)uts_ns;
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#endif
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if (!write)
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down_read(&uts_sem);
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else
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down_write(&uts_sem);
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return which;
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}
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static void put_uts(ctl_table *table, int write, void *which)
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{
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if (!write)
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up_read(&uts_sem);
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else
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up_write(&uts_sem);
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}
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#ifdef CONFIG_PROC_FS
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/*
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* Special case of dostring for the UTS structure. This has locks
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* to observe. Should this be in kernel/sys.c ????
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*/
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static int proc_do_uts_string(ctl_table *table, int write, struct file *filp,
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void __user *buffer, size_t *lenp, loff_t *ppos)
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{
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struct ctl_table uts_table;
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int r;
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memcpy(&uts_table, table, sizeof(uts_table));
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uts_table.data = get_uts(table, write);
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r = proc_dostring(&uts_table,write,filp,buffer,lenp, ppos);
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put_uts(table, write, uts_table.data);
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return r;
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}
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#else
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#define proc_do_uts_string NULL
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#endif
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#ifdef CONFIG_SYSCTL_SYSCALL
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/* The generic string strategy routine: */
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static int sysctl_uts_string(ctl_table *table, int __user *name, int nlen,
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void __user *oldval, size_t __user *oldlenp,
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void __user *newval, size_t newlen)
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{
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struct ctl_table uts_table;
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int r, write;
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write = newval && newlen;
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memcpy(&uts_table, table, sizeof(uts_table));
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uts_table.data = get_uts(table, write);
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r = sysctl_string(&uts_table, name, nlen,
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oldval, oldlenp, newval, newlen);
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put_uts(table, write, uts_table.data);
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return r;
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}
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#else
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#define sysctl_uts_string NULL
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#endif
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static struct ctl_table uts_kern_table[] = {
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{
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.ctl_name = KERN_OSTYPE,
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.procname = "ostype",
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.data = init_uts_ns.name.sysname,
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.maxlen = sizeof(init_uts_ns.name.sysname),
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.mode = 0444,
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.proc_handler = proc_do_uts_string,
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.strategy = sysctl_uts_string,
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},
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{
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.ctl_name = KERN_OSRELEASE,
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.procname = "osrelease",
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.data = init_uts_ns.name.release,
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.maxlen = sizeof(init_uts_ns.name.release),
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.mode = 0444,
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.proc_handler = proc_do_uts_string,
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.strategy = sysctl_uts_string,
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},
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{
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.ctl_name = KERN_VERSION,
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.procname = "version",
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.data = init_uts_ns.name.version,
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.maxlen = sizeof(init_uts_ns.name.version),
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.mode = 0444,
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.proc_handler = proc_do_uts_string,
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.strategy = sysctl_uts_string,
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},
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{
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.ctl_name = KERN_NODENAME,
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.procname = "hostname",
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.data = init_uts_ns.name.nodename,
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.maxlen = sizeof(init_uts_ns.name.nodename),
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.mode = 0644,
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.proc_handler = proc_do_uts_string,
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.strategy = sysctl_uts_string,
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},
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{
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.ctl_name = KERN_DOMAINNAME,
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.procname = "domainname",
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.data = init_uts_ns.name.domainname,
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.maxlen = sizeof(init_uts_ns.name.domainname),
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.mode = 0644,
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.proc_handler = proc_do_uts_string,
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.strategy = sysctl_uts_string,
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},
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{}
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};
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static struct ctl_table uts_root_table[] = {
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{
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.ctl_name = CTL_KERN,
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.procname = "kernel",
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.mode = 0555,
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.child = uts_kern_table,
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},
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{}
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};
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static int __init utsname_sysctl_init(void)
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{
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register_sysctl_table(uts_root_table);
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return 0;
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}
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__initcall(utsname_sysctl_init);
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