[RFC PATCH v3 06/10] lib: sysctl handling (kernel glue code)

[Hajime Tazaki <tazaki@sfc.wide.ad.jp>]

This interacts with fs/proc_fs.c for sysctl-like interface registed via
lib_init() API.

Signed-off-by: Hajime Tazaki <tazaki@sfc.wide.ad.jp>
---
 arch/lib/sysctl.c | 270 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 270 insertions(+)
 create mode 100644 arch/lib/sysctl.c

diff --git a/arch/lib/sysctl.c b/arch/lib/sysctl.c
new file mode 100644
index 0000000..5f08f9f
--- /dev/null
+++ b/arch/lib/sysctl.c
@@ -0,0 +1,270 @@
+/*
+ * sysctl wrapper for library version of Linux kernel
+ * Copyright (c) 2015 INRIA, Hajime Tazaki
+ *
+ * Author: Mathieu Lacage <mathieu.lacage@gmail.com>
+ *         Hajime Tazaki <tazaki@sfc.wide.ad.jp>
+ */
+
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/mman.h>
+#include <linux/ratelimit.h>
+#include <linux/proc_fs.h>
+#include "sim-assert.h"
+#include "sim-types.h"
+
+int drop_caches_sysctl_handler(struct ctl_table *table, int write,
+			       void *buffer, size_t *length, loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
+					void *buffer, size_t *length,
+					loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
+				   void *buffer, size_t *length, loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+
+int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write,
+					    void *buffer, size_t *length,
+					    loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+int dirty_background_ratio_handler(struct ctl_table *table, int write,
+				   void *buffer, size_t *lenp,
+				   loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+int dirty_background_bytes_handler(struct ctl_table *table, int write,
+				   void *buffer, size_t *lenp,
+				   loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+int dirty_ratio_handler(struct ctl_table *table, int write,
+			void *buffer, size_t *lenp,
+			loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+int dirty_bytes_handler(struct ctl_table *table, int write,
+			void *buffer, size_t *lenp,
+			loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+int dirty_writeback_centisecs_handler(struct ctl_table *table, int write,
+				      void *buffer, size_t *length,
+				      loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+int scan_unevictable_handler(struct ctl_table *table, int write,
+			     void __user *buffer,
+			     size_t *length, loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+int sched_rt_handler(struct ctl_table *table, int write,
+		     void __user *buffer, size_t *lenp,
+		     loff_t *ppos)
+{
+	lib_assert(false);
+	return 0;
+}
+
+int sysctl_overcommit_memory = OVERCOMMIT_GUESS;
+int sysctl_overcommit_ratio = 50;
+int sysctl_panic_on_oom = 0;
+int sysctl_oom_dump_tasks = 0;
+int sysctl_oom_kill_allocating_task = 0;
+int sysctl_nr_trim_pages = 0;
+int sysctl_drop_caches = 0;
+int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES - 1] = { 32 };
+unsigned int sysctl_sched_child_runs_first = 0;
+unsigned int sysctl_sched_compat_yield = 0;
+unsigned int sysctl_sched_rt_period = 1000000;
+int sysctl_sched_rt_runtime = 950000;
+
+int vm_highmem_is_dirtyable;
+unsigned long vm_dirty_bytes = 0;
+int vm_dirty_ratio = 20;
+int dirty_background_ratio = 10;
+unsigned int dirty_expire_interval = 30 * 100;
+unsigned int dirty_writeback_interval = 5 * 100;
+unsigned long dirty_background_bytes = 0;
+int percpu_pagelist_fraction = 0;
+int panic_timeout = 0;
+int panic_on_oops = 0;
+int printk_delay_msec = 0;
+int panic_on_warn = 0;
+DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10);
+
+#define RESERVED_PIDS 300
+int pid_max = PID_MAX_DEFAULT;
+int pid_max_min = RESERVED_PIDS + 1;
+int pid_max_max = PID_MAX_LIMIT;
+int min_free_kbytes = 1024;
+int max_threads = 100;
+int laptop_mode = 0;
+
+#define DEFAULT_MESSAGE_LOGLEVEL 4
+#define MINIMUM_CONSOLE_LOGLEVEL 1
+#define DEFAULT_CONSOLE_LOGLEVEL 7
+int console_printk[4] = {
+	DEFAULT_CONSOLE_LOGLEVEL,       /* console_loglevel */
+	DEFAULT_MESSAGE_LOGLEVEL,       /* default_message_loglevel */
+	MINIMUM_CONSOLE_LOGLEVEL,       /* minimum_console_loglevel */
+	DEFAULT_CONSOLE_LOGLEVEL,       /* default_console_loglevel */
+};
+
+int print_fatal_signals = 0;
+unsigned int core_pipe_limit = 0;
+int core_uses_pid = 0;
+int vm_swappiness = 60;
+int nr_pdflush_threads = 0;
+unsigned long scan_unevictable_pages = 0;
+int suid_dumpable = 0;
+int page_cluster = 0;
+int block_dump = 0;
+int C_A_D = 0;
+#include <linux/nsproxy.h>
+struct nsproxy init_nsproxy;
+#include <linux/reboot.h>
+char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
+unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
+unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
+
+int pdflush_proc_obsolete(struct ctl_table *table, int write,
+			  void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	return nr_pdflush_threads;
+}
+#include <linux/fs.h>
+
+/**
+ * Honestly, I don't understand half of that code.
+ * It was modeled after fs/proc/proc_sysctl.c proc_sys_readdir
+ *
+ * Me either ;) (Hajime, Jan 2013)
+ */
+
+/* from proc_sysctl.c (XXX) */
+extern struct ctl_table_root sysctl_table_root;
+void ctl_table_first_entry(struct ctl_dir *dir,
+		 struct ctl_table_header **phead, struct ctl_table **pentry);
+void ctl_table_next_entry(struct ctl_table_header **phead, struct ctl_table **pentry);
+struct ctl_table *ctl_table_find_entry(struct ctl_table_header **phead,
+			     struct ctl_dir *dir, const char *name,
+			     int namelen);
+struct ctl_dir *ctl_table_xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir);
+/* for init_net (XXX, should be fixed) */
+#include <net/net_namespace.h>
+
+static void iterate_table_recursive(const struct SimSysIterator *iter,
+				    struct ctl_table_header *head)
+{
+	struct ctl_table *entry;
+
+	for (entry = head->ctl_table; entry->procname; entry++) {
+		bool may_read = (head->ctl_table->mode & MAY_READ);
+		bool may_write = (head->ctl_table->mode & MAY_WRITE);
+		int flags = 0;
+
+		flags |= may_read ? SIM_SYS_FILE_READ : 0;
+		flags |= may_write ? SIM_SYS_FILE_WRITE : 0;
+		iter->report_file(iter, entry->procname, flags,
+				  (struct SimSysFile *)entry);
+	}
+}
+
+
+static void iterate_recursive(const struct SimSysIterator *iter,
+			      struct ctl_table_header *head)
+{
+	struct ctl_table_header *h = NULL;
+	struct ctl_table *entry;
+	struct ctl_dir *ctl_dir;
+
+	ctl_dir = container_of(head, struct ctl_dir, header);
+	for (ctl_table_first_entry(ctl_dir, &h, &entry); h;
+	     ctl_table_next_entry(&h, &entry)) {
+		struct ctl_dir *dir;
+		int ret;
+		const char *procname;
+
+		/* copy from sysctl_follow_link () */
+		if (S_ISLNK(entry->mode)) {
+			dir = ctl_table_xlate_dir(&init_net.sysctls, h->parent);
+			if (IS_ERR(dir)) {
+				ret = PTR_ERR(dir);
+				lib_assert(false);
+			} else {
+				procname = entry->procname;
+				h = NULL;
+				entry =
+					ctl_table_find_entry(&h, dir, procname,
+							     strlen(procname));
+				ret = -ENOENT;
+			}
+		}
+
+		if (S_ISDIR(entry->mode)) {
+			iter->report_start_dir(iter, entry->procname);
+			iterate_recursive(iter, h);
+			iter->report_end_dir(iter);
+		} else
+			iterate_table_recursive(iter, h);
+	}
+
+}
+
+
+void lib_sys_iterate_files(const struct SimSysIterator *iter)
+{
+	struct ctl_table_header *root =
+		&sysctl_table_root.default_set.dir.header;
+
+	iterate_recursive(iter, root);
+}
+
+int lib_sys_file_read(const struct SimSysFile *file, char *buffer, int size,
+		      int offset)
+{
+	struct ctl_table *table = (struct ctl_table *)file;
+	loff_t ppos = offset;
+	size_t result = size;
+	int error;
+
+	error = table->proc_handler(table, 0, buffer, &result, &ppos);
+	return result;
+}
+int lib_sys_file_write(const struct SimSysFile *file, const char *buffer,
+		       int size, int offset)
+{
+	struct ctl_table *table = (struct ctl_table *)file;
+	loff_t ppos = offset;
+	size_t result = size;
+	int error;
+
+	error = table->proc_handler(table, 1, (char *)buffer, &result, &ppos);
+	return result;
+}
-- 
2.1.0