diff options
Diffstat (limited to 'ipc/ipc_sysctl.c')
| -rw-r--r-- | ipc/ipc_sysctl.c | 68 |
1 files changed, 66 insertions, 2 deletions
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c index 7f4235bed51..d3497465cc0 100644 --- a/ipc/ipc_sysctl.c +++ b/ipc/ipc_sysctl.c @@ -15,6 +15,8 @@ #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) { @@ -24,6 +26,27 @@ static void *get_ipc(ctl_table *table) return which; } +/* + * Routine that is called when a tunable has successfully been changed by + * hand and it has a callback routine registered on the ipc namespace notifier + * chain: we don't want such tunables to be recomputed anymore upon memory + * add/remove or ipc namespace creation/removal. + * They can come back to a recomputable state by being set to a <0 value. + */ +static void tunable_set_callback(int val) +{ + if (val >= 0) + 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) @@ -35,6 +58,24 @@ static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp, 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_set_callback(*((int *)(ipc_table.data))); + + 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) { @@ -49,6 +90,7 @@ static int proc_ipc_doulongvec_minmax(ctl_table *table, int write, #else #define proc_ipc_doulongvec_minmax NULL #define proc_ipc_dointvec NULL +#define proc_ipc_callback_dointvec NULL #endif #ifdef CONFIG_SYSCTL_SYSCALL @@ -90,8 +132,30 @@ static int sysctl_ipc_data(ctl_table *table, int __user *name, int nlen, } return 1; } + +static int sysctl_ipc_registered_data(ctl_table *table, int __user *name, + int nlen, void __user *oldval, size_t __user *oldlenp, + void __user *newval, size_t newlen) +{ + int rc; + + rc = sysctl_ipc_data(table, name, nlen, oldval, oldlenp, newval, + newlen); + + if (newval && newlen && rc > 0) { + /* + * Tunable has successfully been changed from userland + */ + int *data = get_ipc(table); + + tunable_set_callback(*data); + } + + return rc; +} #else #define sysctl_ipc_data NULL +#define sysctl_ipc_registered_data NULL #endif static struct ctl_table ipc_kern_table[] = { @@ -137,8 +201,8 @@ static struct ctl_table ipc_kern_table[] = { .data = &init_ipc_ns.msg_ctlmni, .maxlen = sizeof (init_ipc_ns.msg_ctlmni), .mode = 0644, - .proc_handler = proc_ipc_dointvec, - .strategy = sysctl_ipc_data, + .proc_handler = proc_ipc_callback_dointvec, + .strategy = sysctl_ipc_registered_data, }, { .ctl_name = KERN_MSGMNB, |