From 9e3f1d0805b2d919904dd9a4ff0d956314cc3cba Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@nbd.name>
Date: Sat, 8 Jul 2017 08:20:09 +0200
Subject: debloat: procfs

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 fs/locks.c               |  2 ++
 fs/proc/Kconfig          |  5 +++++
 fs/proc/consoles.c       |  3 +++
 fs/proc/proc_tty.c       | 11 ++++++++++-
 include/net/snmp.h       | 18 +++++++++++++++++-
 ipc/msg.c                |  3 +++
 ipc/sem.c                |  2 ++
 ipc/shm.c                |  2 ++
 ipc/util.c               |  3 +++
 kernel/exec_domain.c     |  2 ++
 kernel/irq/proc.c        |  9 +++++++++
 kernel/time/timer_list.c |  2 ++
 mm/vmalloc.c             |  2 ++
 mm/vmstat.c              |  8 +++++---
 net/8021q/vlanproc.c     |  6 ++++++
 net/core/net-procfs.c    | 18 ++++++++++++------
 net/core/sock.c          |  2 ++
 net/ipv4/fib_trie.c      | 18 ++++++++++++------
 net/ipv4/proc.c          |  3 +++
 net/ipv4/route.c         |  3 +++
 20 files changed, 105 insertions(+), 17 deletions(-)

--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2897,6 +2897,8 @@ static const struct seq_operations locks
 
 static int __init proc_locks_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
 	proc_create_seq_private("locks", 0, NULL, &locks_seq_operations,
 			sizeof(struct locks_iterator), NULL);
 	return 0;
--- a/fs/proc/Kconfig
+++ b/fs/proc/Kconfig
@@ -101,6 +101,11 @@ config PROC_CHILDREN
 	  Say Y if you are running any user-space software which takes benefit from
 	  this interface. For example, rkt is such a piece of software.
 
+config PROC_STRIPPED
+	default n
+	depends on EXPERT
+	bool "Strip non-essential /proc functionality to reduce code size"
+
 config PROC_PID_ARCH_STATUS
 	def_bool n
 	depends on PROC_FS
--- a/fs/proc/consoles.c
+++ b/fs/proc/consoles.c
@@ -107,6 +107,9 @@ static const struct seq_operations conso
 
 static int __init proc_consoles_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
+
 	proc_create_seq("consoles", 0, NULL, &consoles_op);
 	return 0;
 }
--- a/fs/proc/proc_tty.c
+++ b/fs/proc/proc_tty.c
@@ -131,7 +131,10 @@ static const struct seq_operations tty_d
 void proc_tty_register_driver(struct tty_driver *driver)
 {
 	struct proc_dir_entry *ent;
-		
+
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	if (!driver->driver_name || driver->proc_entry ||
 	    !driver->ops->proc_show)
 		return;
@@ -148,6 +151,9 @@ void proc_tty_unregister_driver(struct t
 {
 	struct proc_dir_entry *ent;
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	ent = driver->proc_entry;
 	if (!ent)
 		return;
@@ -162,6 +168,9 @@ void proc_tty_unregister_driver(struct t
  */
 void __init proc_tty_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	if (!proc_mkdir("tty", NULL))
 		return;
 	proc_mkdir("tty/ldisc", NULL);	/* Preserved: it's userspace visible */
--- a/include/net/snmp.h
+++ b/include/net/snmp.h
@@ -124,6 +124,21 @@ struct linux_tls_mib {
 #define DECLARE_SNMP_STAT(type, name)	\
 	extern __typeof__(type) __percpu *name
 
+#ifdef CONFIG_PROC_STRIPPED
+#define __SNMP_STATS_DUMMY(mib)	\
+	do { (void) mib->mibs[0]; } while(0)
+
+#define __SNMP_INC_STATS(mib, field) __SNMP_STATS_DUMMY(mib)
+#define SNMP_INC_STATS_ATOMIC_LONG(mib, field) __SNMP_STATS_DUMMY(mib)
+#define SNMP_INC_STATS(mib, field) __SNMP_STATS_DUMMY(mib)
+#define SNMP_DEC_STATS(mib, field) __SNMP_STATS_DUMMY(mib)
+#define __SNMP_ADD_STATS(mib, field, addend) __SNMP_STATS_DUMMY(mib)
+#define SNMP_ADD_STATS(mib, field, addend) __SNMP_STATS_DUMMY(mib)
+#define SNMP_UPD_PO_STATS(mib, basefield, addend) __SNMP_STATS_DUMMY(mib)
+#define __SNMP_UPD_PO_STATS(mib, basefield, addend) __SNMP_STATS_DUMMY(mib)
+
+#else
+
 #define __SNMP_INC_STATS(mib, field)	\
 			__this_cpu_inc(mib->mibs[field])
 
@@ -154,8 +169,9 @@ struct linux_tls_mib {
 		__this_cpu_add(ptr[basefield##OCTETS], addend);	\
 	} while (0)
 
+#endif
 
-#if BITS_PER_LONG==32
+#if (BITS_PER_LONG==32) && !defined(CONFIG_PROC_STRIPPED)
 
 #define __SNMP_ADD_STATS64(mib, field, addend) 				\
 	do {								\
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -1370,6 +1370,9 @@ void __init msg_init(void)
 {
 	msg_init_ns(&init_ipc_ns);
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	ipc_init_proc_interface("sysvipc/msg",
 				"       key      msqid perms      cbytes       qnum lspid lrpid   uid   gid  cuid  cgid      stime      rtime      ctime\n",
 				IPC_MSG_IDS, sysvipc_msg_proc_show);
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -268,6 +268,8 @@ void sem_exit_ns(struct ipc_namespace *n
 void __init sem_init(void)
 {
 	sem_init_ns(&init_ipc_ns);
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
 	ipc_init_proc_interface("sysvipc/sem",
 				"       key      semid perms      nsems   uid   gid  cuid  cgid      otime      ctime\n",
 				IPC_SEM_IDS, sysvipc_sem_proc_show);
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -154,6 +154,8 @@ pure_initcall(ipc_ns_init);
 
 void __init shm_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
 	ipc_init_proc_interface("sysvipc/shm",
 #if BITS_PER_LONG <= 32
 				"       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -141,6 +141,9 @@ void __init ipc_init_proc_interface(cons
 	struct proc_dir_entry *pde;
 	struct ipc_proc_iface *iface;
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	iface = kmalloc(sizeof(*iface), GFP_KERNEL);
 	if (!iface)
 		return;
--- a/kernel/exec_domain.c
+++ b/kernel/exec_domain.c
@@ -29,6 +29,8 @@ static int execdomains_proc_show(struct
 
 static int __init proc_execdomains_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
 	proc_create_single("execdomains", 0, NULL, execdomains_proc_show);
 	return 0;
 }
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -341,6 +341,9 @@ void register_irq_proc(unsigned int irq,
 	void __maybe_unused *irqp = (void *)(unsigned long) irq;
 	char name [MAX_NAMELEN];
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED) && !IS_ENABLED(CONFIG_SMP))
+		return;
+
 	if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
 		return;
 
@@ -394,6 +397,9 @@ void unregister_irq_proc(unsigned int ir
 {
 	char name [MAX_NAMELEN];
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED) && !IS_ENABLED(CONFIG_SMP))
+		return;
+
 	if (!root_irq_dir || !desc->dir)
 		return;
 #ifdef CONFIG_SMP
@@ -432,6 +438,9 @@ void init_irq_proc(void)
 	unsigned int irq;
 	struct irq_desc *desc;
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED) && !IS_ENABLED(CONFIG_SMP))
+		return;
+
 	/* create /proc/irq */
 	root_irq_dir = proc_mkdir("irq", NULL);
 	if (!root_irq_dir)
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -350,6 +350,8 @@ static int __init init_timer_list_procfs
 {
 	struct proc_dir_entry *pe;
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
 	pe = proc_create_seq_private("timer_list", 0400, NULL, &timer_list_sops,
 			sizeof(struct timer_list_iter), NULL);
 	if (!pe)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -4455,6 +4455,8 @@ static const struct seq_operations vmall
 
 static int __init proc_vmalloc_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
 	if (IS_ENABLED(CONFIG_NUMA))
 		proc_create_seq_private("vmallocinfo", 0400, NULL,
 				&vmalloc_op,
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -2135,10 +2135,12 @@ void __init init_mm_internals(void)
 	start_shepherd_timer();
 #endif
 #ifdef CONFIG_PROC_FS
-	proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
-	proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED)) {
+		proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
+		proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
+		proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
+	}
 	proc_create_seq("vmstat", 0444, NULL, &vmstat_op);
-	proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
 #endif
 }
 
--- a/net/8021q/vlanproc.c
+++ b/net/8021q/vlanproc.c
@@ -93,6 +93,9 @@ void vlan_proc_cleanup(struct net *net)
 {
 	struct vlan_net *vn = net_generic(net, vlan_net_id);
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	if (vn->proc_vlan_conf)
 		remove_proc_entry(name_conf, vn->proc_vlan_dir);
 
@@ -112,6 +115,9 @@ int __net_init vlan_proc_init(struct net
 {
 	struct vlan_net *vn = net_generic(net, vlan_net_id);
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
+
 	vn->proc_vlan_dir = proc_net_mkdir(net, name_root, net->proc_net);
 	if (!vn->proc_vlan_dir)
 		goto err;
--- a/net/core/net-procfs.c
+++ b/net/core/net-procfs.c
@@ -327,10 +327,12 @@ static int __net_init dev_proc_net_init(
 	if (!proc_create_net("dev", 0444, net->proc_net, &dev_seq_ops,
 			sizeof(struct seq_net_private)))
 		goto out;
-	if (!proc_create_seq("softnet_stat", 0444, net->proc_net,
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED) &&
+			!proc_create_seq("softnet_stat", 0444, net->proc_net,
 			 &softnet_seq_ops))
 		goto out_dev;
-	if (!proc_create_net("ptype", 0444, net->proc_net, &ptype_seq_ops,
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED) &&
+			!proc_create_net("ptype", 0444, net->proc_net, &ptype_seq_ops,
 			sizeof(struct seq_net_private)))
 		goto out_softnet;
 
@@ -340,9 +342,11 @@ static int __net_init dev_proc_net_init(
 out:
 	return rc;
 out_ptype:
-	remove_proc_entry("ptype", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED))
+		remove_proc_entry("ptype", net->proc_net);
 out_softnet:
-	remove_proc_entry("softnet_stat", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED))
+		remove_proc_entry("softnet_stat", net->proc_net);
 out_dev:
 	remove_proc_entry("dev", net->proc_net);
 	goto out;
@@ -352,8 +356,10 @@ static void __net_exit dev_proc_net_exit
 {
 	wext_proc_exit(net);
 
-	remove_proc_entry("ptype", net->proc_net);
-	remove_proc_entry("softnet_stat", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED)) {
+		remove_proc_entry("ptype", net->proc_net);
+		remove_proc_entry("softnet_stat", net->proc_net);
+	}
 	remove_proc_entry("dev", net->proc_net);
 }
 
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -4148,6 +4148,8 @@ static __net_initdata struct pernet_oper
 
 static int __init proto_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
 	return register_pernet_subsys(&proto_net_ops);
 }
 
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -3036,11 +3036,13 @@ static const struct seq_operations fib_r
 
 int __net_init fib_proc_init(struct net *net)
 {
-	if (!proc_create_net("fib_trie", 0444, net->proc_net, &fib_trie_seq_ops,
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED) &&
+			!proc_create_net("fib_trie", 0444, net->proc_net, &fib_trie_seq_ops,
 			sizeof(struct fib_trie_iter)))
 		goto out1;
 
-	if (!proc_create_net_single("fib_triestat", 0444, net->proc_net,
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED) &&
+			!proc_create_net_single("fib_triestat", 0444, net->proc_net,
 			fib_triestat_seq_show, NULL))
 		goto out2;
 
@@ -3051,17 +3053,21 @@ int __net_init fib_proc_init(struct net
 	return 0;
 
 out3:
-	remove_proc_entry("fib_triestat", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED))
+		remove_proc_entry("fib_triestat", net->proc_net);
 out2:
-	remove_proc_entry("fib_trie", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED))
+		remove_proc_entry("fib_trie", net->proc_net);
 out1:
 	return -ENOMEM;
 }
 
 void __net_exit fib_proc_exit(struct net *net)
 {
-	remove_proc_entry("fib_trie", net->proc_net);
-	remove_proc_entry("fib_triestat", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED)) {
+		remove_proc_entry("fib_trie", net->proc_net);
+		remove_proc_entry("fib_triestat", net->proc_net);
+	}
 	remove_proc_entry("route", net->proc_net);
 }
 
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -557,5 +557,8 @@ static __net_initdata struct pernet_oper
 
 int __init ip_misc_proc_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
+
 	return register_pernet_subsys(&ip_proc_ops);
 }
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -381,6 +381,9 @@ static struct pernet_operations ip_rt_pr
 
 static int __init ip_rt_proc_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
+
 	return register_pernet_subsys(&ip_rt_proc_ops);
 }
 
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -266,7 +266,7 @@ void __inet_twsk_schedule(struct inet_ti
 	 */
 
 	if (!rearm) {
-		bool kill = timeo <= 4*HZ;
+		bool __maybe_unused  kill = timeo <= 4*HZ;
 
 		__NET_INC_STATS(twsk_net(tw), kill ? LINUX_MIB_TIMEWAITKILLED :
 						     LINUX_MIB_TIMEWAITED);
