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_FS 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, struct file *filp, 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,filp,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 61 #ifdef CONFIG_SYSCTL_SYSCALL 62 /* The generic string strategy routine: */ 63 static int sysctl_uts_string(ctl_table *table, int __user *name, int nlen, 64 void __user *oldval, size_t __user *oldlenp, 65 void __user *newval, size_t newlen) 66 { 67 struct ctl_table uts_table; 68 int r, write; 69 write = newval && newlen; 70 memcpy(&uts_table, table, sizeof(uts_table)); 71 uts_table.data = get_uts(table, write); 72 r = sysctl_string(&uts_table, name, nlen, 73 oldval, oldlenp, newval, newlen); 74 put_uts(table, write, uts_table.data); 75 return r; 76 } 77 #else 78 #define sysctl_uts_string NULL 79 #endif 80 81 static struct ctl_table uts_kern_table[] = { 82 { 83 .ctl_name = KERN_OSTYPE, 84 .procname = "ostype", 85 .data = init_uts_ns.name.sysname, 86 .maxlen = sizeof(init_uts_ns.name.sysname), 87 .mode = 0444, 88 .proc_handler = proc_do_uts_string, 89 .strategy = sysctl_uts_string, 90 }, 91 { 92 .ctl_name = KERN_OSRELEASE, 93 .procname = "osrelease", 94 .data = init_uts_ns.name.release, 95 .maxlen = sizeof(init_uts_ns.name.release), 96 .mode = 0444, 97 .proc_handler = proc_do_uts_string, 98 .strategy = sysctl_uts_string, 99 }, 100 { 101 .ctl_name = KERN_VERSION, 102 .procname = "version", 103 .data = init_uts_ns.name.version, 104 .maxlen = sizeof(init_uts_ns.name.version), 105 .mode = 0444, 106 .proc_handler = proc_do_uts_string, 107 .strategy = sysctl_uts_string, 108 }, 109 { 110 .ctl_name = KERN_NODENAME, 111 .procname = "hostname", 112 .data = init_uts_ns.name.nodename, 113 .maxlen = sizeof(init_uts_ns.name.nodename), 114 .mode = 0644, 115 .proc_handler = proc_do_uts_string, 116 .strategy = sysctl_uts_string, 117 }, 118 { 119 .ctl_name = KERN_DOMAINNAME, 120 .procname = "domainname", 121 .data = init_uts_ns.name.domainname, 122 .maxlen = sizeof(init_uts_ns.name.domainname), 123 .mode = 0644, 124 .proc_handler = proc_do_uts_string, 125 .strategy = sysctl_uts_string, 126 }, 127 {} 128 }; 129 130 static struct ctl_table uts_root_table[] = { 131 { 132 .ctl_name = CTL_KERN, 133 .procname = "kernel", 134 .mode = 0555, 135 .child = uts_kern_table, 136 }, 137 {} 138 }; 139 140 static int __init utsname_sysctl_init(void) 141 { 142 register_sysctl_table(uts_root_table); 143 return 0; 144 } 145 146 __initcall(utsname_sysctl_init); 147