4154342bf1
The sysctl core is preparing to only expose instances of struct ctl_table as "const". This will also affect the ctl_table argument of sysctl handlers. As the function prototype of all sysctl handlers throughout the tree needs to stay consistent that change will be done in one commit. To reduce the size of that final commit, switch utility functions which are not bound by "typedef proc_handler" to "const struct ctl_table". No functional change. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Reviewed-by: Joel Granados <j.granados@samsung.com> Signed-off-by: Joel Granados <j.granados@samsung.com>
145 lines
3.4 KiB
C
145 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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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#include <linux/export.h>
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#include <linux/uts.h>
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#include <linux/utsname.h>
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#include <linux/random.h>
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#include <linux/sysctl.h>
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#include <linux/wait.h>
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#include <linux/rwsem.h>
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#ifdef CONFIG_PROC_SYSCTL
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static void *get_uts(const struct ctl_table *table)
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{
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char *which = table->data;
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struct uts_namespace *uts_ns;
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uts_ns = current->nsproxy->uts_ns;
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which = (which - (char *)&init_uts_ns) + (char *)uts_ns;
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return which;
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}
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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(struct ctl_table *table, int write,
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void *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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char tmp_data[__NEW_UTS_LEN + 1];
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memcpy(&uts_table, table, sizeof(uts_table));
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uts_table.data = tmp_data;
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/*
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* Buffer the value in tmp_data so that proc_dostring() can be called
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* without holding any locks.
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* We also need to read the original value in the write==1 case to
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* support partial writes.
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*/
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down_read(&uts_sem);
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memcpy(tmp_data, get_uts(table), sizeof(tmp_data));
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up_read(&uts_sem);
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r = proc_dostring(&uts_table, write, buffer, lenp, ppos);
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if (write) {
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/*
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* Write back the new value.
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* Note that, since we dropped uts_sem, the result can
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* theoretically be incorrect if there are two parallel writes
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* at non-zero offsets to the same sysctl.
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*/
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add_device_randomness(tmp_data, sizeof(tmp_data));
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down_write(&uts_sem);
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memcpy(get_uts(table), tmp_data, sizeof(tmp_data));
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up_write(&uts_sem);
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proc_sys_poll_notify(table->poll);
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}
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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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static DEFINE_CTL_TABLE_POLL(hostname_poll);
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static DEFINE_CTL_TABLE_POLL(domainname_poll);
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// Note: update 'enum uts_proc' to match any changes to this table
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static struct ctl_table uts_kern_table[] = {
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{
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.procname = "arch",
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.data = init_uts_ns.name.machine,
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.maxlen = sizeof(init_uts_ns.name.machine),
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.mode = 0444,
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.proc_handler = proc_do_uts_string,
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},
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{
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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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},
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{
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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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},
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{
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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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},
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{
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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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.poll = &hostname_poll,
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},
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{
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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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.poll = &domainname_poll,
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},
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};
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#ifdef CONFIG_PROC_SYSCTL
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/*
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* Notify userspace about a change in a certain entry of uts_kern_table,
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* identified by the parameter proc.
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*/
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void uts_proc_notify(enum uts_proc proc)
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{
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struct ctl_table *table = &uts_kern_table[proc];
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proc_sys_poll_notify(table->poll);
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}
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#endif
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static int __init utsname_sysctl_init(void)
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{
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register_sysctl("kernel", uts_kern_table);
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return 0;
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}
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device_initcall(utsname_sysctl_init);
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