/* * Copyright (C) 2007 * * Author: Eric Biederman <ebiederm@xmision.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation, version 2 of the * License. */ #include <linux/module.h> #include <linux/ipc.h> #include <linux/nsproxy.h> #include <linux/sysctl.h> #include <linux/uaccess.h> #include <linux/ipc_namespace.h> #include <linux/msg.h> #include "util.h" static void *get_ipc(ctl_table *table) { char *which = table->data; struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns; return which; } /* * Routine that is called when the file "auto_msgmni" has successfully been * written. * Two values are allowed: * 0: unregister msgmni's callback routine from the ipc namespace notifier * chain. This means that msgmni won't be recomputed anymore upon memory * add/remove or ipc namespace creation/removal. * 1: register back the callback routine. */ static void ipc_auto_callback(int val) { if (!val) unregister_ipcns_notifier(current->nsproxy->ipc_ns); else { /* * Re-enable automatic recomputing only if not already * enabled. */ recompute_msgmni(current->nsproxy->ipc_ns); cond_register_ipcns_notifier(current->nsproxy->ipc_ns); } } #ifdef CONFIG_PROC_FS static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos) { struct ctl_table ipc_table; memcpy(&ipc_table, table, sizeof(ipc_table)); ipc_table.data = get_ipc(table); return proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos); } static int proc_ipc_callback_dointvec(ctl_table *table, int write, struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos) { struct ctl_table ipc_table; size_t lenp_bef = *lenp; int rc; memcpy(&ipc_table, table, sizeof(ipc_table)); ipc_table.data = get_ipc(table); rc = proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos); if (write && !rc && lenp_bef == *lenp) /* * Tunable has successfully been changed by hand. Disable its * automatic adjustment. This simply requires unregistering * the notifiers that trigger recalculation. */ unregister_ipcns_notifier(current->nsproxy->ipc_ns); return rc; } static int proc_ipc_doulongvec_minmax(ctl_table *table, int write, struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos) { struct ctl_table ipc_table; memcpy(&ipc_table, table, sizeof(ipc_table)); ipc_table.data = get_ipc(table); return proc_doulongvec_minmax(&ipc_table, write, filp, buffer, lenp, ppos); } static int proc_ipcauto_dointvec_minmax(ctl_table *table, int write, struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos) { struct ctl_table ipc_table; size_t lenp_bef = *lenp; int oldval; int rc; memcpy(&ipc_table, table, sizeof(ipc_table)); ipc_table.data = get_ipc(table); oldval = *((int *)(ipc_table.data)); rc = proc_dointvec_minmax(&ipc_table, write, filp, buffer, lenp, ppos); if (write && !rc && lenp_bef == *lenp) { int newval = *((int *)(ipc_table.data)); /* * The file "auto_msgmni" has correctly been set. * React by (un)registering the corresponding tunable, if the * value has changed. */ if (newval != oldval) ipc_auto_callback(newval); } return rc; } #else #define proc_ipc_doulongvec_minmax NULL #define proc_ipc_dointvec NULL #define proc_ipc_callback_dointvec NULL #define proc_ipcauto_dointvec_minmax NULL #endif #ifdef CONFIG_SYSCTL_SYSCALL /* The generic sysctl ipc data routine. */ static int sysctl_ipc_data(ctl_table *table, void __user *oldval, size_t __user *oldlenp, void __user *newval, size_t newlen) { size_t len; void *data; /* Get out of I don't have a variable */ if (!table->data || !table->maxlen) return -ENOTDIR; data = get_ipc(table); if (!data) return -ENOTDIR; if (oldval && oldlenp) { if (get_user(len, oldlenp)) return -EFAULT; if (len) { if (len > table->maxlen) len = table->maxlen; if (copy_to_user(oldval, data, len)) return -EFAULT; if (put_user(len, oldlenp)) return -EFAULT; } } if (newval && newlen) { if (newlen > table->maxlen) newlen = table->maxlen; if (copy_from_user(data, newval, newlen)) return -EFAULT; } return 1; } static int sysctl_ipc_registered_data(ctl_table *table, void __user *oldval, size_t __user *oldlenp, void __user *newval, size_t newlen) { int rc; rc = sysctl_ipc_data(table, oldval, oldlenp, newval, newlen); if (newval && newlen && rc > 0) /* * Tunable has successfully been changed from userland */ unregister_ipcns_notifier(current->nsproxy->ipc_ns); return rc; } #else #define sysctl_ipc_data NULL #define sysctl_ipc_registered_data NULL #endif static int zero; static int one = 1; static struct ctl_table ipc_kern_table[] = { { .ctl_name = KERN_SHMMAX, .procname = "shmmax", .data = &init_ipc_ns.shm_ctlmax, .maxlen = sizeof (init_ipc_ns.shm_ctlmax), .mode = 0644, .proc_handler = proc_ipc_doulongvec_minmax, .strategy = sysctl_ipc_data, }, { .ctl_name = KERN_SHMALL, .procname = "shmall", .data = &init_ipc_ns.shm_ctlall, .maxlen = sizeof (init_ipc_ns.shm_ctlall), .mode = 0644, .proc_handler = proc_ipc_doulongvec_minmax, .strategy = sysctl_ipc_data, }, { .ctl_name = KERN_SHMMNI, .procname = "shmmni", .data = &init_ipc_ns.shm_ctlmni, .maxlen = sizeof (init_ipc_ns.shm_ctlmni), .mode = 0644, .proc_handler = proc_ipc_dointvec, .strategy = sysctl_ipc_data, }, { .ctl_name = KERN_MSGMAX, .procname = "msgmax", .data = &init_ipc_ns.msg_ctlmax, .maxlen = sizeof (init_ipc_ns.msg_ctlmax), .mode = 0644, .proc_handler = proc_ipc_dointvec, .strategy = sysctl_ipc_data, }, { .ctl_name = KERN_MSGMNI, .procname = "msgmni", .data = &init_ipc_ns.msg_ctlmni, .maxlen = sizeof (init_ipc_ns.msg_ctlmni), .mode = 0644, .proc_handler = proc_ipc_callback_dointvec, .strategy = sysctl_ipc_registered_data, }, { .ctl_name = KERN_MSGMNB, .procname = "msgmnb", .data = &init_ipc_ns.msg_ctlmnb, .maxlen = sizeof (init_ipc_ns.msg_ctlmnb), .mode = 0644, .proc_handler = proc_ipc_dointvec, .strategy = sysctl_ipc_data, }, { .ctl_name = KERN_SEM, .procname = "sem", .data = &init_ipc_ns.sem_ctls, .maxlen = 4*sizeof (int), .mode = 0644, .proc_handler = proc_ipc_dointvec, .strategy = sysctl_ipc_data, }, { .ctl_name = CTL_UNNUMBERED, .procname = "auto_msgmni", .data = &init_ipc_ns.auto_msgmni, .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_ipcauto_dointvec_minmax, .extra1 = &zero, .extra2 = &one, }, {} }; static struct ctl_table ipc_root_table[] = { { .ctl_name = CTL_KERN, .procname = "kernel", .mode = 0555, .child = ipc_kern_table, }, {} }; static int __init ipc_sysctl_init(void) { register_sysctl_table(ipc_root_table); return 0; } __initcall(ipc_sysctl_init);