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/version.h> 16 #include <linux/sysctl.h> 17 18 static void *get_uts(ctl_table *table, int write) 19 { 20 char *which = table->data; 21 struct uts_namespace *uts_ns; 22 23 uts_ns = current->nsproxy->uts_ns; 24 which = (which - (char *)&init_uts_ns) + (char *)uts_ns; 25 26 if (!write) 27 down_read(&uts_sem); 28 else 29 down_write(&uts_sem); 30 return which; 31 } 32 33 static void put_uts(ctl_table *table, int write, void *which) 34 { 35 if (!write) 36 up_read(&uts_sem); 37 else 38 up_write(&uts_sem); 39 } 40 41 #ifdef CONFIG_PROC_FS 42 /* 43 * Special case of dostring for the UTS structure. This has locks 44 * to observe. Should this be in kernel/sys.c ???? 45 */ 46 static int proc_do_uts_string(ctl_table *table, int write, struct file *filp, 47 void __user *buffer, size_t *lenp, loff_t *ppos) 48 { 49 struct ctl_table uts_table; 50 int r; 51 memcpy(&uts_table, table, sizeof(uts_table)); 52 uts_table.data = get_uts(table, write); 53 r = proc_dostring(&uts_table,write,filp,buffer,lenp, ppos); 54 put_uts(table, write, uts_table.data); 55 return r; 56 } 57 #else 58 #define proc_do_uts_string NULL 59 #endif 60 61 62 #ifdef CONFIG_SYSCTL_SYSCALL 63 /* The generic string strategy routine: */ 64 static int sysctl_uts_string(ctl_table *table, int __user *name, int nlen, 65 void __user *oldval, size_t __user *oldlenp, 66 void __user *newval, size_t newlen) 67 { 68 struct ctl_table uts_table; 69 int r, write; 70 write = newval && newlen; 71 memcpy(&uts_table, table, sizeof(uts_table)); 72 uts_table.data = get_uts(table, write); 73 r = sysctl_string(&uts_table, name, nlen, 74 oldval, oldlenp, newval, newlen); 75 put_uts(table, write, uts_table.data); 76 return r; 77 } 78 #else 79 #define sysctl_uts_string NULL 80 #endif 81 82 static struct ctl_table uts_kern_table[] = { 83 { 84 .ctl_name = KERN_OSTYPE, 85 .procname = "ostype", 86 .data = init_uts_ns.name.sysname, 87 .maxlen = sizeof(init_uts_ns.name.sysname), 88 .mode = 0444, 89 .proc_handler = proc_do_uts_string, 90 .strategy = sysctl_uts_string, 91 }, 92 { 93 .ctl_name = KERN_OSRELEASE, 94 .procname = "osrelease", 95 .data = init_uts_ns.name.release, 96 .maxlen = sizeof(init_uts_ns.name.release), 97 .mode = 0444, 98 .proc_handler = proc_do_uts_string, 99 .strategy = sysctl_uts_string, 100 }, 101 { 102 .ctl_name = KERN_VERSION, 103 .procname = "version", 104 .data = init_uts_ns.name.version, 105 .maxlen = sizeof(init_uts_ns.name.version), 106 .mode = 0444, 107 .proc_handler = proc_do_uts_string, 108 .strategy = sysctl_uts_string, 109 }, 110 { 111 .ctl_name = KERN_NODENAME, 112 .procname = "hostname", 113 .data = init_uts_ns.name.nodename, 114 .maxlen = sizeof(init_uts_ns.name.nodename), 115 .mode = 0644, 116 .proc_handler = proc_do_uts_string, 117 .strategy = sysctl_uts_string, 118 }, 119 { 120 .ctl_name = KERN_DOMAINNAME, 121 .procname = "domainname", 122 .data = init_uts_ns.name.domainname, 123 .maxlen = sizeof(init_uts_ns.name.domainname), 124 .mode = 0644, 125 .proc_handler = proc_do_uts_string, 126 .strategy = sysctl_uts_string, 127 }, 128 {} 129 }; 130 131 static struct ctl_table uts_root_table[] = { 132 { 133 .ctl_name = CTL_KERN, 134 .procname = "kernel", 135 .mode = 0555, 136 .child = uts_kern_table, 137 }, 138 {} 139 }; 140 141 static int __init utsname_sysctl_init(void) 142 { 143 register_sysctl_table(uts_root_table); 144 return 0; 145 } 146 147 __initcall(utsname_sysctl_init); 148