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Quelle utsname_sysctl.c Sprache: C |
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// SPDX-License-Identifier: GPL-2.0-only
/* * Copyright (C) 2007 * * Author: Eric Biederman <ebiederm@xmision.com> */ #include <linux/export.h> #include <linux/uts.h> #include <linux/utsname.h> #include <linux/random.h> #include <linux/sysctl.h> #include <linux/wait.h> #include <linux/rwsem.h> #ifdef CONFIG_PROC_SYSCTL static void *get_uts(const 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(const 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. */ add_device_randomness(tmp_data, sizeof(tmp_data)); 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); // Note: update 'enum uts_proc' to match any changes to this table static const struct ctl_table uts_kern_table[] = { { .procname = "arch", .data = init_uts_ns.name.machine, .maxlen = sizeof(init_uts_ns.name.machine), .mode = 0444, .proc_handler = proc_do_uts_string, }, { .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, }, }; #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) { const struct ctl_table *table = &uts_kern_table[proc]; proc_sys_poll_notify(table->poll); } #endif static int __init utsname_sysctl_init(void) { register_sysctl("kernel", uts_kern_table); return 0; } device_initcall(utsname_sysctl_init); ¤ Dauer der Verarbeitung: 0.15 Sekunden (vorverarbeitet) ¤*© Formatika GbR, Deutschland |
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2026-03-28