1 /* 2 * Copyright (C) 2007 3 * 4 * Author: Eric Biederman <ebiederm@xmision.com> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation, version 2 of the 9 * License. 10 */ 11 12 #include <linux/module.h> 13 #include <linux/uts.h> 14 #include <linux/utsname.h> 15 #include <linux/sysctl.h> 16 17 static void *get_uts(ctl_table *table, int write) 18 { 19 char *which = table->data; 20 struct uts_namespace *uts_ns; 21 22 uts_ns = current->nsproxy->uts_ns; 23 which = (which - (char *)&init_uts_ns) + (char *)uts_ns; 24 25 if (!write) 26 down_read(&uts_sem); 27 else 28 down_write(&uts_sem); 29 return which; 30 } 31 32 static void put_uts(ctl_table *table, int write, void *which) 33 { 34 if (!write) 35 up_read(&uts_sem); 36 else 37 up_write(&uts_sem); 38 } 39 40 #ifdef CONFIG_PROC_SYSCTL 41 /* 42 * Special case of dostring for the UTS structure. This has locks 43 * to observe. Should this be in kernel/sys.c ???? 44 */ 45 static int proc_do_uts_string(ctl_table *table, int write, 46 void __user *buffer, size_t *lenp, loff_t *ppos) 47 { 48 struct ctl_table uts_table; 49 int r; 50 memcpy(&uts_table, table, sizeof(uts_table)); 51 uts_table.data = get_uts(table, write); 52 r = proc_dostring(&uts_table,write,buffer,lenp, ppos); 53 put_uts(table, write, uts_table.data); 54 return r; 55 } 56 #else 57 #define proc_do_uts_string NULL 58 #endif 59 60 static struct ctl_table uts_kern_table[] = { 61 { 62 .procname = "ostype", 63 .data = init_uts_ns.name.sysname, 64 .maxlen = sizeof(init_uts_ns.name.sysname), 65 .mode = 0444, 66 .proc_handler = proc_do_uts_string, 67 }, 68 { 69 .procname = "osrelease", 70 .data = init_uts_ns.name.release, 71 .maxlen = sizeof(init_uts_ns.name.release), 72 .mode = 0444, 73 .proc_handler = proc_do_uts_string, 74 }, 75 { 76 .procname = "version", 77 .data = init_uts_ns.name.version, 78 .maxlen = sizeof(init_uts_ns.name.version), 79 .mode = 0444, 80 .proc_handler = proc_do_uts_string, 81 }, 82 { 83 .procname = "hostname", 84 .data = init_uts_ns.name.nodename, 85 .maxlen = sizeof(init_uts_ns.name.nodename), 86 .mode = 0644, 87 .proc_handler = proc_do_uts_string, 88 }, 89 { 90 .procname = "domainname", 91 .data = init_uts_ns.name.domainname, 92 .maxlen = sizeof(init_uts_ns.name.domainname), 93 .mode = 0644, 94 .proc_handler = proc_do_uts_string, 95 }, 96 {} 97 }; 98 99 static struct ctl_table uts_root_table[] = { 100 { 101 .procname = "kernel", 102 .mode = 0555, 103 .child = uts_kern_table, 104 }, 105 {} 106 }; 107 108 static int __init utsname_sysctl_init(void) 109 { 110 register_sysctl_table(uts_root_table); 111 return 0; 112 } 113 114 __initcall(utsname_sysctl_init); 115