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