[PATCH] sysctl: simplify ipc ns specific sysctls
authorEric W. Biederman <ebiederm@xmission.com>
Fri, 8 Dec 2006 10:39:56 +0000 (02:39 -0800)
committerLinus Torvalds <torvalds@woody.osdl.org>
Fri, 8 Dec 2006 16:29:03 +0000 (08:29 -0800)
Refactor the ipc sysctl support so that it is simpler, more readable, and
prepares for fixing the bug with the wrong values being returned in the
sys_sysctl interface.

The function proc_do_ipc_string() was misnamed as it never handled strings.
It's magic of when to work with strings and when to work with longs belonged
in the sysctl table.  I couldn't tell if the code would work if you disabled
the ipc namespace but it certainly looked like it would have problems.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
kernel/sysctl.c

index 77ea4fc386eff58bb7372a3f1329ed4ac5d9bb7b..10474a63a111ca17c630cd729ee4134fe0ebd968 100644 (file)
@@ -92,7 +92,9 @@ extern char modprobe_path[];
 extern int sg_big_buff;
 #endif
 #ifdef CONFIG_SYSVIPC
-static int proc_do_ipc_string(ctl_table *table, int write, struct file *filp,
+static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp,
+               void __user *buffer, size_t *lenp, loff_t *ppos);
+static int proc_ipc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
                void __user *buffer, size_t *lenp, loff_t *ppos);
 #endif
 
@@ -189,6 +191,18 @@ static void put_uts(ctl_table *table, int write, void *which)
                up_write(&uts_sem);
 }
 
+#ifdef CONFIG_SYSVIPC
+static void *get_ipc(ctl_table *table, int write)
+{
+       char *which = table->data;
+       struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
+       which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
+       return which;
+}
+#else
+#define get_ipc(T,W) ((T)->data)
+#endif
+
 /* /proc declarations: */
 
 #ifdef CONFIG_PROC_SYSCTL
@@ -458,58 +472,58 @@ static ctl_table kern_table[] = {
        {
                .ctl_name       = KERN_SHMMAX,
                .procname       = "shmmax",
-               .data           = NULL,
-               .maxlen         = sizeof (size_t),
+               .data           = &init_ipc_ns.shm_ctlmax,
+               .maxlen         = sizeof (init_ipc_ns.shm_ctlmax),
                .mode           = 0644,
-               .proc_handler   = &proc_do_ipc_string,
+               .proc_handler   = &proc_ipc_doulongvec_minmax,
        },
        {
                .ctl_name       = KERN_SHMALL,
                .procname       = "shmall",
-               .data           = NULL,
-               .maxlen         = sizeof (size_t),
+               .data           = &init_ipc_ns.shm_ctlall,
+               .maxlen         = sizeof (init_ipc_ns.shm_ctlall),
                .mode           = 0644,
-               .proc_handler   = &proc_do_ipc_string,
+               .proc_handler   = &proc_ipc_doulongvec_minmax,
        },
        {
                .ctl_name       = KERN_SHMMNI,
                .procname       = "shmmni",
-               .data           = NULL,
-               .maxlen         = sizeof (int),
+               .data           = &init_ipc_ns.shm_ctlmni,
+               .maxlen         = sizeof (init_ipc_ns.shm_ctlmni),
                .mode           = 0644,
-               .proc_handler   = &proc_do_ipc_string,
+               .proc_handler   = &proc_ipc_dointvec,
        },
        {
                .ctl_name       = KERN_MSGMAX,
                .procname       = "msgmax",
-               .data           = NULL,
-               .maxlen         = sizeof (int),
+               .data           = &init_ipc_ns.msg_ctlmax,
+               .maxlen         = sizeof (init_ipc_ns.msg_ctlmax),
                .mode           = 0644,
-               .proc_handler   = &proc_do_ipc_string,
+               .proc_handler   = &proc_ipc_dointvec,
        },
        {
                .ctl_name       = KERN_MSGMNI,
                .procname       = "msgmni",
-               .data           = NULL,
-               .maxlen         = sizeof (int),
+               .data           = &init_ipc_ns.msg_ctlmni,
+               .maxlen         = sizeof (init_ipc_ns.msg_ctlmni),
                .mode           = 0644,
-               .proc_handler   = &proc_do_ipc_string,
+               .proc_handler   = &proc_ipc_dointvec,
        },
        {
                .ctl_name       = KERN_MSGMNB,
                .procname       =  "msgmnb",
-               .data           = NULL,
-               .maxlen         = sizeof (int),
+               .data           = &init_ipc_ns.msg_ctlmnb,
+               .maxlen         = sizeof (init_ipc_ns.msg_ctlmnb),
                .mode           = 0644,
-               .proc_handler   = &proc_do_ipc_string,
+               .proc_handler   = &proc_ipc_dointvec,
        },
        {
                .ctl_name       = KERN_SEM,
                .procname       = "sem",
-               .data           = NULL,
+               .data           = &init_ipc_ns.sem_ctls,
                .maxlen         = 4*sizeof (int),
                .mode           = 0644,
-               .proc_handler   = &proc_do_ipc_string,
+               .proc_handler   = &proc_ipc_dointvec,
        },
 #endif
 #ifdef CONFIG_MAGIC_SYSRQ
@@ -2319,46 +2333,24 @@ int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
 }
 
 #ifdef CONFIG_SYSVIPC
-static int proc_do_ipc_string(ctl_table *table, int write, struct file *filp,
-               void __user *buffer, size_t *lenp, loff_t *ppos)
+static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp,
+       void __user *buffer, size_t *lenp, loff_t *ppos)
 {
-       void *data;
-       struct ipc_namespace *ns;
-
-       ns = current->nsproxy->ipc_ns;
-
-       switch (table->ctl_name) {
-       case KERN_SHMMAX:
-               data = &ns->shm_ctlmax;
-               goto proc_minmax;
-       case KERN_SHMALL:
-               data = &ns->shm_ctlall;
-               goto proc_minmax;
-       case KERN_SHMMNI:
-               data = &ns->shm_ctlmni;
-               break;
-       case KERN_MSGMAX:
-               data = &ns->msg_ctlmax;
-               break;
-       case KERN_MSGMNI:
-               data = &ns->msg_ctlmni;
-               break;
-       case KERN_MSGMNB:
-               data = &ns->msg_ctlmnb;
-               break;
-       case KERN_SEM:
-               data = &ns->sem_ctls;
-               break;
-       default:
-               return -EINVAL;
-       }
-
-       return __do_proc_dointvec(data, table, write, filp, buffer,
+       void *which;
+       which = get_ipc(table, write);
+       return __do_proc_dointvec(which, table, write, filp, buffer,
                        lenp, ppos, NULL, NULL);
-proc_minmax:
-       return __do_proc_doulongvec_minmax(data, table, write, filp, buffer,
+}
+
+static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
+       struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+       void *which;
+       which = get_ipc(table, write);
+       return __do_proc_doulongvec_minmax(which, table, write, filp, buffer,
                        lenp, ppos, 1l, 1l);
 }
+
 #endif
 
 static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,