[PATCH] sysctl: Allow /proc/sys without sys_sysctl

Since sys_sysctl is deprecated start allow it to be compiled out.  This
should catch any remaining user space code that cares, and paves the way
for further sysctl cleanups.

[akpm@osdl.org: If sys_sysctl() is not compiled-in, emit a warning]
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>

9 files changed, 81 insertions, 96 deletions

diff --git a/arch/ia64/ia32/sys_ia32.c b/arch/ia64/ia32/sys_ia32.c
index 6aa3c51619ca..bddbd22706ed 100644
--- a/arch/ia64/ia32/sys_ia32.c
+++ b/arch/ia64/ia32/sys_ia32.c
@@ -1942,7 +1942,7 @@ struct sysctl32 {
         unsigned int    __unused[4];
 };
 
-#ifdef CONFIG_SYSCTL
+#ifdef CONFIG_SYSCTL_SYSCALL
 asmlinkage long
 sys32_sysctl (struct sysctl32 __user *args)
 {
diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index dc500e20cf14..43b1162d714f 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -991,7 +991,7 @@ struct sysctl_args32
         unsigned int __unused[4];
 };
 
-#ifdef CONFIG_SYSCTL
+#ifdef CONFIG_SYSCTL_SYSCALL
 
 asmlinkage long sys32_sysctl(struct sysctl_args32 __user *args)
 {
@@ -1032,7 +1032,7 @@ asmlinkage long sys32_sysctl(struct sysctl_args32 __user *args)
         return error;
 }
 
-#endif /* CONFIG_SYSCTL */
+#endif /* CONFIG_SYSCTL_SYSCALL */
 
 asmlinkage long sys32_newuname(struct new_utsname __user * name)
 {
diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c
index 2e292863e982..5e391fc25340 100644
--- a/arch/powerpc/kernel/sys_ppc32.c
+++ b/arch/powerpc/kernel/sys_ppc32.c
@@ -740,7 +740,7 @@ asmlinkage long compat_sys_umask(u32 mask)
         return sys_umask((int)mask);
 }
 
-#ifdef CONFIG_SYSCTL
+#ifdef CONFIG_SYSCTL_SYSCALL
 struct __sysctl_args32 {
         u32 name;
         int nlen;
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 785c9f70ac98..91b2884fa5c4 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -708,7 +708,7 @@ asmlinkage long sys32_sendfile64(int out_fd, int in_fd,
         return ret;
 }
 
-#ifdef CONFIG_SYSCTL
+#ifdef CONFIG_SYSCTL_SYSCALL
 struct __sysctl_args32 {
         u32 name;
         int nlen;
diff --git a/arch/sparc64/kernel/sys_sparc32.c b/arch/sparc64/kernel/sys_sparc32.c
index c88ae23ce812..69444f266e2d 100644
--- a/arch/sparc64/kernel/sys_sparc32.c
+++ b/arch/sparc64/kernel/sys_sparc32.c
@@ -1016,7 +1016,7 @@ struct __sysctl_args32 {
 
 asmlinkage long sys32_sysctl(struct __sysctl_args32 __user *args)
 {
-#ifndef CONFIG_SYSCTL
+#ifndef CONFIG_SYSCTL_SYSCALL
         return -ENOSYS;
 #else
         struct __sysctl_args32 tmp;
diff --git a/arch/x86_64/ia32/sys_ia32.c b/arch/x86_64/ia32/sys_ia32.c
index b0e82c7947dc..f280d3665f4b 100644
--- a/arch/x86_64/ia32/sys_ia32.c
+++ b/arch/x86_64/ia32/sys_ia32.c
@@ -648,7 +648,7 @@ sys32_pause(void)
 }
 
 
-#ifdef CONFIG_SYSCTL
+#ifdef CONFIG_SYSCTL_SYSCALL
 struct sysctl_ia32 {
         unsigned int    name;
         int             nlen;
diff --git a/fs/Kconfig b/fs/Kconfig
index a27002668bd3..d311198bba43 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -826,6 +826,25 @@ config PROC_VMCORE
         help
         Exports the dump image of crashed kernel in ELF format.
 
+config PROC_SYSCTL
+        bool "Sysctl support (/proc/sys)" if EMBEDDED
+        depends on PROC_FS
+        select SYSCTL
+        default y
+        ---help---
+          The sysctl interface provides a means of dynamically changing
+          certain kernel parameters and variables on the fly without requiring
+          a recompile of the kernel or reboot of the system.  The primary
+          interface is through /proc/sys.  If you say Y here a tree of
+          modifiable sysctl entries will be generated beneath the
+          /proc/sys directory. They are explained in the files
+          in <file:Documentation/sysctl/>.  Note that enabling this
+          option will enlarge the kernel by at least 8 KB.
+
+          As it is generally a good thing, you should say Y here unless
+          building a kernel for install/rescue disks or your system is very
+          limited in memory.
+
 config SYSFS
         bool "sysfs file system support" if EMBEDDED
         default y
diff --git a/init/Kconfig b/init/Kconfig
index 9a7656f0b5ec..4381006dd666 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -273,21 +273,24 @@ config UID16
           This enables the legacy 16-bit UID syscall wrappers.
 
 config SYSCTL
-        bool "Sysctl support" if EMBEDDED
-        default y
+        bool
+
+config SYSCTL_SYSCALL
+        bool "Sysctl syscall support"
+        default n
+        select SYSCTL
         ---help---
-          The sysctl interface provides a means of dynamically changing
-          certain kernel parameters and variables on the fly without requiring
-          a recompile of the kernel or reboot of the system.  The primary
-          interface consists of a system call, but if you say Y to "/proc
-          file system support", a tree of modifiable sysctl entries will be
-          generated beneath the /proc/sys directory. They are explained in the
-          files in <file:Documentation/sysctl/>.  Note that enabling this
-          option will enlarge the kernel by at least 8 KB.
-
-          As it is generally a good thing, you should say Y here unless
-          building a kernel for install/rescue disks or your system is very
-          limited in memory.
+          Enable the deprecated sysctl system call.  sys_sysctl uses
+          binary paths that have been found to be a major pain to maintain
+          and use.  The interface in /proc/sys is now the primary and what
+          everyone uses.
+
+          Nothing has been using the binary sysctl interface for some time
+          time now so nothing should break if you disable sysctl syscall
+          support, and you kernel will get marginally smaller.
+
+          Unless you have an application that uses the sys_syscall interface
+          you should probably say N here.
 
 config KALLSYMS
          bool "Load all symbols for debugging/kksymoops" if EMBEDDED
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index bcb3a181dbb2..8bfa7d117c54 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -137,8 +137,11 @@ extern int no_unaligned_warning;
 extern int max_lock_depth;
 #endif
 
-static int parse_table(int __user *, int, void __user *, size_t __user *, void __user *, size_t,
-                       ctl_table *, void **);
+#ifdef CONFIG_SYSCTL_SYSCALL
+static int parse_table(int __user *, int, void __user *, size_t __user *,
+                void __user *, size_t, ctl_table *, void **);
+#endif
+
 static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
                   void __user *buffer, size_t *lenp, loff_t *ppos);
 
@@ -165,7 +168,7 @@ int sysctl_legacy_va_layout;
 
 /* /proc declarations: */
 
-#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_PROC_SYSCTL
 
 static ssize_t proc_readsys(struct file *, char __user *, size_t, loff_t *);
 static ssize_t proc_writesys(struct file *, const char __user *, size_t, loff_t *);
@@ -1166,12 +1169,13 @@ static void start_unregistering(struct ctl_table_header *p)
 
 void __init sysctl_init(void)
 {
-#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_PROC_SYSCTL
         register_proc_table(root_table, proc_sys_root, &root_table_header);
         init_irq_proc();
 #endif
 }
 
+#ifdef CONFIG_SYSCTL_SYSCALL
 int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *oldlenp,
                void __user *newval, size_t newlen)
 {
@@ -1225,6 +1229,7 @@ asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
         unlock_kernel();
         return error;
 }
+#endif /* CONFIG_SYSCTL_SYSCALL */
 
 /*
  * ctl_perm does NOT grant the superuser all rights automatically, because
@@ -1251,6 +1256,7 @@ static inline int ctl_perm(ctl_table *table, int op)
         return test_perm(table->mode, op);
 }
 
+#ifdef CONFIG_SYSCTL_SYSCALL
 static int parse_table(int __user *name, int nlen,
                        void __user *oldval, size_t __user *oldlenp,
                        void __user *newval, size_t newlen,
@@ -1340,6 +1346,7 @@ int do_sysctl_strategy (ctl_table *table,
         }
         return 0;
 }
+#endif /* CONFIG_SYSCTL_SYSCALL */
 
 /**
  * register_sysctl_table - register a sysctl hierarchy
@@ -1427,7 +1434,7 @@ struct ctl_table_header *register_sysctl_table(ctl_table * table,
         else
                 list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
         spin_unlock(&sysctl_lock);
-#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_PROC_SYSCTL
         register_proc_table(table, proc_sys_root, tmp);
 #endif
         return tmp;
@@ -1445,18 +1452,31 @@ void unregister_sysctl_table(struct ctl_table_header * header)
         might_sleep();
         spin_lock(&sysctl_lock);
         start_unregistering(header);
-#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_PROC_SYSCTL
         unregister_proc_table(header->ctl_table, proc_sys_root);
 #endif
         spin_unlock(&sysctl_lock);
         kfree(header);
 }
 
+#else /* !CONFIG_SYSCTL */
+struct ctl_table_header * register_sysctl_table(ctl_table * table,
+                                                int insert_at_head)
+{
+        return NULL;
+}
+
+void unregister_sysctl_table(struct ctl_table_header * table)
+{
+}
+
+#endif /* CONFIG_SYSCTL */
+
 /*
  * /proc/sys support
  */
 
-#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_PROC_SYSCTL
 
 /* Scan the sysctl entries in table and add them all into /proc */
 static void register_proc_table(ctl_table * table, struct proc_dir_entry *root, void *set)
@@ -2318,6 +2338,7 @@ int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
 #endif /* CONFIG_PROC_FS */
 
 
+#ifdef CONFIG_SYSCTL_SYSCALL
 /*
  * General sysctl support routines 
  */
@@ -2460,11 +2481,19 @@ int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen,
         return 1;
 }
 
-#else /* CONFIG_SYSCTL */
+#else /* CONFIG_SYSCTL_SYSCALL */
 
 
 asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
 {
+        static int msg_count;
+
+        if (msg_count < 5) {
+                msg_count++;
+                printk(KERN_INFO
+                        "warning: process `%s' used the removed sysctl "
+                        "system call\n", current->comm);
+        }
         return -ENOSYS;
 }
 
@@ -2496,73 +2525,7 @@ int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen,
         return -ENOSYS;
 }
 
-int proc_dostring(ctl_table *table, int write, struct file *filp,
-                  void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-        return -ENOSYS;
-}
-
-int proc_dointvec(ctl_table *table, int write, struct file *filp,
-                  void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-        return -ENOSYS;
-}
-
-int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
-                        void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-        return -ENOSYS;
-}
-
-int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
-                    void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-        return -ENOSYS;
-}
-
-int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
-                          void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-        return -ENOSYS;
-}
-
-int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
-                          void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-        return -ENOSYS;
-}
-
-int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
-                             void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-        return -ENOSYS;
-}
-
-int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
-                    void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-        return -ENOSYS;
-}
-
-int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
-                                      struct file *filp,
-                                      void __user *buffer,
-                                      size_t *lenp, loff_t *ppos)
-{
-    return -ENOSYS;
-}
-
-struct ctl_table_header * register_sysctl_table(ctl_table * table, 
-                                                int insert_at_head)
-{
-        return NULL;
-}
-
-void unregister_sysctl_table(struct ctl_table_header * table)
-{
-}
-
-#endif /* CONFIG_SYSCTL */
+#endif /* CONFIG_SYSCTL_SYSCALL */
 
 /*
  * No sense putting this after each symbol definition, twice,