From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- kernel/utsname_sysctl.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 kernel/utsname_sysctl.c (limited to 'kernel/utsname_sysctl.c') diff --git a/kernel/utsname_sysctl.c b/kernel/utsname_sysctl.c new file mode 100644 index 000000000..4ca61d498 --- /dev/null +++ b/kernel/utsname_sysctl.c @@ -0,0 +1,144 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2007 + * + * Author: Eric Biederman + */ + +#include +#include +#include +#include +#include +#include + +#ifdef CONFIG_PROC_SYSCTL + +static void *get_uts(struct ctl_table *table) +{ + char *which = table->data; + struct uts_namespace *uts_ns; + + uts_ns = current->nsproxy->uts_ns; + which = (which - (char *)&init_uts_ns) + (char *)uts_ns; + + return which; +} + +/* + * Special case of dostring for the UTS structure. This has locks + * to observe. Should this be in kernel/sys.c ???? + */ +static int proc_do_uts_string(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table uts_table; + int r; + char tmp_data[__NEW_UTS_LEN + 1]; + + memcpy(&uts_table, table, sizeof(uts_table)); + uts_table.data = tmp_data; + + /* + * Buffer the value in tmp_data so that proc_dostring() can be called + * without holding any locks. + * We also need to read the original value in the write==1 case to + * support partial writes. + */ + down_read(&uts_sem); + memcpy(tmp_data, get_uts(table), sizeof(tmp_data)); + up_read(&uts_sem); + r = proc_dostring(&uts_table, write, buffer, lenp, ppos); + + if (write) { + /* + * Write back the new value. + * Note that, since we dropped uts_sem, the result can + * theoretically be incorrect if there are two parallel writes + * at non-zero offsets to the same sysctl. + */ + down_write(&uts_sem); + memcpy(get_uts(table), tmp_data, sizeof(tmp_data)); + up_write(&uts_sem); + proc_sys_poll_notify(table->poll); + } + + return r; +} +#else +#define proc_do_uts_string NULL +#endif + +static DEFINE_CTL_TABLE_POLL(hostname_poll); +static DEFINE_CTL_TABLE_POLL(domainname_poll); + +static struct ctl_table uts_kern_table[] = { + { + .procname = "ostype", + .data = init_uts_ns.name.sysname, + .maxlen = sizeof(init_uts_ns.name.sysname), + .mode = 0444, + .proc_handler = proc_do_uts_string, + }, + { + .procname = "osrelease", + .data = init_uts_ns.name.release, + .maxlen = sizeof(init_uts_ns.name.release), + .mode = 0444, + .proc_handler = proc_do_uts_string, + }, + { + .procname = "version", + .data = init_uts_ns.name.version, + .maxlen = sizeof(init_uts_ns.name.version), + .mode = 0444, + .proc_handler = proc_do_uts_string, + }, + { + .procname = "hostname", + .data = init_uts_ns.name.nodename, + .maxlen = sizeof(init_uts_ns.name.nodename), + .mode = 0644, + .proc_handler = proc_do_uts_string, + .poll = &hostname_poll, + }, + { + .procname = "domainname", + .data = init_uts_ns.name.domainname, + .maxlen = sizeof(init_uts_ns.name.domainname), + .mode = 0644, + .proc_handler = proc_do_uts_string, + .poll = &domainname_poll, + }, + {} +}; + +static struct ctl_table uts_root_table[] = { + { + .procname = "kernel", + .mode = 0555, + .child = uts_kern_table, + }, + {} +}; + +#ifdef CONFIG_PROC_SYSCTL +/* + * Notify userspace about a change in a certain entry of uts_kern_table, + * identified by the parameter proc. + */ +void uts_proc_notify(enum uts_proc proc) +{ + struct ctl_table *table = &uts_kern_table[proc]; + + proc_sys_poll_notify(table->poll); +} +#endif + +static int __init utsname_sysctl_init(void) +{ + register_sysctl_table(uts_root_table); + return 0; +} + +device_initcall(utsname_sysctl_init); -- cgit v1.2.3