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authorLen Brown <len.brown@intel.com>2012-04-06 21:48:59 -0400
committerLen Brown <len.brown@intel.com>2012-04-06 21:48:59 -0400
commiteeaab2d8af2cf1d36d7086f22e9de42d6dd2995c (patch)
tree369b9c91a6d808944f07d2290fec6f9fe2731904 /kernel/sysctl.c
parentee01e663373343c63e0e3d364d09f6155378dbcc (diff)
parentaaef292acf3a78d9c0bb6fb72226077d286b45d7 (diff)
Merge branches 'idle-fix' and 'misc' into release
Diffstat (limited to 'kernel/sysctl.c')
-rw-r--r--kernel/sysctl.c514
1 files changed, 10 insertions, 504 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index f487f257e05e..52b3a06a02f8 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -23,6 +23,7 @@
23#include <linux/swap.h> 23#include <linux/swap.h>
24#include <linux/slab.h> 24#include <linux/slab.h>
25#include <linux/sysctl.h> 25#include <linux/sysctl.h>
26#include <linux/bitmap.h>
26#include <linux/signal.h> 27#include <linux/signal.h>
27#include <linux/printk.h> 28#include <linux/printk.h>
28#include <linux/proc_fs.h> 29#include <linux/proc_fs.h>
@@ -58,6 +59,7 @@
58#include <linux/oom.h> 59#include <linux/oom.h>
59#include <linux/kmod.h> 60#include <linux/kmod.h>
60#include <linux/capability.h> 61#include <linux/capability.h>
62#include <linux/binfmts.h>
61 63
62#include <asm/uaccess.h> 64#include <asm/uaccess.h>
63#include <asm/processor.h> 65#include <asm/processor.h>
@@ -67,6 +69,9 @@
67#include <asm/stacktrace.h> 69#include <asm/stacktrace.h>
68#include <asm/io.h> 70#include <asm/io.h>
69#endif 71#endif
72#ifdef CONFIG_SPARC
73#include <asm/setup.h>
74#endif
70#ifdef CONFIG_BSD_PROCESS_ACCT 75#ifdef CONFIG_BSD_PROCESS_ACCT
71#include <linux/acct.h> 76#include <linux/acct.h>
72#endif 77#endif
@@ -141,7 +146,6 @@ static const int cap_last_cap = CAP_LAST_CAP;
141#include <linux/inotify.h> 146#include <linux/inotify.h>
142#endif 147#endif
143#ifdef CONFIG_SPARC 148#ifdef CONFIG_SPARC
144#include <asm/system.h>
145#endif 149#endif
146 150
147#ifdef CONFIG_SPARC64 151#ifdef CONFIG_SPARC64
@@ -192,20 +196,6 @@ static int sysrq_sysctl_handler(ctl_table *table, int write,
192 196
193#endif 197#endif
194 198
195static struct ctl_table root_table[];
196static struct ctl_table_root sysctl_table_root;
197static struct ctl_table_header root_table_header = {
198 {{.count = 1,
199 .ctl_table = root_table,
200 .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}},
201 .root = &sysctl_table_root,
202 .set = &sysctl_table_root.default_set,
203};
204static struct ctl_table_root sysctl_table_root = {
205 .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
206 .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
207};
208
209static struct ctl_table kern_table[]; 199static struct ctl_table kern_table[];
210static struct ctl_table vm_table[]; 200static struct ctl_table vm_table[];
211static struct ctl_table fs_table[]; 201static struct ctl_table fs_table[];
@@ -222,7 +212,7 @@ int sysctl_legacy_va_layout;
222 212
223/* The default sysctl tables: */ 213/* The default sysctl tables: */
224 214
225static struct ctl_table root_table[] = { 215static struct ctl_table sysctl_base_table[] = {
226 { 216 {
227 .procname = "kernel", 217 .procname = "kernel",
228 .mode = 0555, 218 .mode = 0555,
@@ -1559,490 +1549,12 @@ static struct ctl_table dev_table[] = {
1559 { } 1549 { }
1560}; 1550};
1561 1551
1562static DEFINE_SPINLOCK(sysctl_lock); 1552int __init sysctl_init(void)
1563
1564/* called under sysctl_lock */
1565static int use_table(struct ctl_table_header *p)
1566{ 1553{
1567 if (unlikely(p->unregistering)) 1554 register_sysctl_table(sysctl_base_table);
1568 return 0;
1569 p->used++;
1570 return 1;
1571}
1572
1573/* called under sysctl_lock */
1574static void unuse_table(struct ctl_table_header *p)
1575{
1576 if (!--p->used)
1577 if (unlikely(p->unregistering))
1578 complete(p->unregistering);
1579}
1580
1581/* called under sysctl_lock, will reacquire if has to wait */
1582static void start_unregistering(struct ctl_table_header *p)
1583{
1584 /*
1585 * if p->used is 0, nobody will ever touch that entry again;
1586 * we'll eliminate all paths to it before dropping sysctl_lock
1587 */
1588 if (unlikely(p->used)) {
1589 struct completion wait;
1590 init_completion(&wait);
1591 p->unregistering = &wait;
1592 spin_unlock(&sysctl_lock);
1593 wait_for_completion(&wait);
1594 spin_lock(&sysctl_lock);
1595 } else {
1596 /* anything non-NULL; we'll never dereference it */
1597 p->unregistering = ERR_PTR(-EINVAL);
1598 }
1599 /*
1600 * do not remove from the list until nobody holds it; walking the
1601 * list in do_sysctl() relies on that.
1602 */
1603 list_del_init(&p->ctl_entry);
1604}
1605
1606void sysctl_head_get(struct ctl_table_header *head)
1607{
1608 spin_lock(&sysctl_lock);
1609 head->count++;
1610 spin_unlock(&sysctl_lock);
1611}
1612
1613void sysctl_head_put(struct ctl_table_header *head)
1614{
1615 spin_lock(&sysctl_lock);
1616 if (!--head->count)
1617 kfree_rcu(head, rcu);
1618 spin_unlock(&sysctl_lock);
1619}
1620
1621struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
1622{
1623 if (!head)
1624 BUG();
1625 spin_lock(&sysctl_lock);
1626 if (!use_table(head))
1627 head = ERR_PTR(-ENOENT);
1628 spin_unlock(&sysctl_lock);
1629 return head;
1630}
1631
1632void sysctl_head_finish(struct ctl_table_header *head)
1633{
1634 if (!head)
1635 return;
1636 spin_lock(&sysctl_lock);
1637 unuse_table(head);
1638 spin_unlock(&sysctl_lock);
1639}
1640
1641static struct ctl_table_set *
1642lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
1643{
1644 struct ctl_table_set *set = &root->default_set;
1645 if (root->lookup)
1646 set = root->lookup(root, namespaces);
1647 return set;
1648}
1649
1650static struct list_head *
1651lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
1652{
1653 struct ctl_table_set *set = lookup_header_set(root, namespaces);
1654 return &set->list;
1655}
1656
1657struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
1658 struct ctl_table_header *prev)
1659{
1660 struct ctl_table_root *root;
1661 struct list_head *header_list;
1662 struct ctl_table_header *head;
1663 struct list_head *tmp;
1664
1665 spin_lock(&sysctl_lock);
1666 if (prev) {
1667 head = prev;
1668 tmp = &prev->ctl_entry;
1669 unuse_table(prev);
1670 goto next;
1671 }
1672 tmp = &root_table_header.ctl_entry;
1673 for (;;) {
1674 head = list_entry(tmp, struct ctl_table_header, ctl_entry);
1675
1676 if (!use_table(head))
1677 goto next;
1678 spin_unlock(&sysctl_lock);
1679 return head;
1680 next:
1681 root = head->root;
1682 tmp = tmp->next;
1683 header_list = lookup_header_list(root, namespaces);
1684 if (tmp != header_list)
1685 continue;
1686
1687 do {
1688 root = list_entry(root->root_list.next,
1689 struct ctl_table_root, root_list);
1690 if (root == &sysctl_table_root)
1691 goto out;
1692 header_list = lookup_header_list(root, namespaces);
1693 } while (list_empty(header_list));
1694 tmp = header_list->next;
1695 }
1696out:
1697 spin_unlock(&sysctl_lock);
1698 return NULL;
1699}
1700
1701struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
1702{
1703 return __sysctl_head_next(current->nsproxy, prev);
1704}
1705
1706void register_sysctl_root(struct ctl_table_root *root)
1707{
1708 spin_lock(&sysctl_lock);
1709 list_add_tail(&root->root_list, &sysctl_table_root.root_list);
1710 spin_unlock(&sysctl_lock);
1711}
1712
1713/*
1714 * sysctl_perm does NOT grant the superuser all rights automatically, because
1715 * some sysctl variables are readonly even to root.
1716 */
1717
1718static int test_perm(int mode, int op)
1719{
1720 if (!current_euid())
1721 mode >>= 6;
1722 else if (in_egroup_p(0))
1723 mode >>= 3;
1724 if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
1725 return 0;
1726 return -EACCES;
1727}
1728
1729int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
1730{
1731 int mode;
1732
1733 if (root->permissions)
1734 mode = root->permissions(root, current->nsproxy, table);
1735 else
1736 mode = table->mode;
1737
1738 return test_perm(mode, op);
1739}
1740
1741static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
1742{
1743 for (; table->procname; table++) {
1744 table->parent = parent;
1745 if (table->child)
1746 sysctl_set_parent(table, table->child);
1747 }
1748}
1749
1750static __init int sysctl_init(void)
1751{
1752 sysctl_set_parent(NULL, root_table);
1753#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1754 sysctl_check_table(current->nsproxy, root_table);
1755#endif
1756 return 0; 1555 return 0;
1757} 1556}
1758 1557
1759core_initcall(sysctl_init);
1760
1761static struct ctl_table *is_branch_in(struct ctl_table *branch,
1762 struct ctl_table *table)
1763{
1764 struct ctl_table *p;
1765 const char *s = branch->procname;
1766
1767 /* branch should have named subdirectory as its first element */
1768 if (!s || !branch->child)
1769 return NULL;
1770
1771 /* ... and nothing else */
1772 if (branch[1].procname)
1773 return NULL;
1774
1775 /* table should contain subdirectory with the same name */
1776 for (p = table; p->procname; p++) {
1777 if (!p->child)
1778 continue;
1779 if (p->procname && strcmp(p->procname, s) == 0)
1780 return p;
1781 }
1782 return NULL;
1783}
1784
1785/* see if attaching q to p would be an improvement */
1786static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
1787{
1788 struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
1789 struct ctl_table *next;
1790 int is_better = 0;
1791 int not_in_parent = !p->attached_by;
1792
1793 while ((next = is_branch_in(by, to)) != NULL) {
1794 if (by == q->attached_by)
1795 is_better = 1;
1796 if (to == p->attached_by)
1797 not_in_parent = 1;
1798 by = by->child;
1799 to = next->child;
1800 }
1801
1802 if (is_better && not_in_parent) {
1803 q->attached_by = by;
1804 q->attached_to = to;
1805 q->parent = p;
1806 }
1807}
1808
1809/**
1810 * __register_sysctl_paths - register a sysctl hierarchy
1811 * @root: List of sysctl headers to register on
1812 * @namespaces: Data to compute which lists of sysctl entries are visible
1813 * @path: The path to the directory the sysctl table is in.
1814 * @table: the top-level table structure
1815 *
1816 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1817 * array. A completely 0 filled entry terminates the table.
1818 *
1819 * The members of the &struct ctl_table structure are used as follows:
1820 *
1821 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1822 * enter a sysctl file
1823 *
1824 * data - a pointer to data for use by proc_handler
1825 *
1826 * maxlen - the maximum size in bytes of the data
1827 *
1828 * mode - the file permissions for the /proc/sys file, and for sysctl(2)
1829 *
1830 * child - a pointer to the child sysctl table if this entry is a directory, or
1831 * %NULL.
1832 *
1833 * proc_handler - the text handler routine (described below)
1834 *
1835 * de - for internal use by the sysctl routines
1836 *
1837 * extra1, extra2 - extra pointers usable by the proc handler routines
1838 *
1839 * Leaf nodes in the sysctl tree will be represented by a single file
1840 * under /proc; non-leaf nodes will be represented by directories.
1841 *
1842 * sysctl(2) can automatically manage read and write requests through
1843 * the sysctl table. The data and maxlen fields of the ctl_table
1844 * struct enable minimal validation of the values being written to be
1845 * performed, and the mode field allows minimal authentication.
1846 *
1847 * There must be a proc_handler routine for any terminal nodes
1848 * mirrored under /proc/sys (non-terminals are handled by a built-in
1849 * directory handler). Several default handlers are available to
1850 * cover common cases -
1851 *
1852 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1853 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1854 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1855 *
1856 * It is the handler's job to read the input buffer from user memory
1857 * and process it. The handler should return 0 on success.
1858 *
1859 * This routine returns %NULL on a failure to register, and a pointer
1860 * to the table header on success.
1861 */
1862struct ctl_table_header *__register_sysctl_paths(
1863 struct ctl_table_root *root,
1864 struct nsproxy *namespaces,
1865 const struct ctl_path *path, struct ctl_table *table)
1866{
1867 struct ctl_table_header *header;
1868 struct ctl_table *new, **prevp;
1869 unsigned int n, npath;
1870 struct ctl_table_set *set;
1871
1872 /* Count the path components */
1873 for (npath = 0; path[npath].procname; ++npath)
1874 ;
1875
1876 /*
1877 * For each path component, allocate a 2-element ctl_table array.
1878 * The first array element will be filled with the sysctl entry
1879 * for this, the second will be the sentinel (procname == 0).
1880 *
1881 * We allocate everything in one go so that we don't have to
1882 * worry about freeing additional memory in unregister_sysctl_table.
1883 */
1884 header = kzalloc(sizeof(struct ctl_table_header) +
1885 (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
1886 if (!header)
1887 return NULL;
1888
1889 new = (struct ctl_table *) (header + 1);
1890
1891 /* Now connect the dots */
1892 prevp = &header->ctl_table;
1893 for (n = 0; n < npath; ++n, ++path) {
1894 /* Copy the procname */
1895 new->procname = path->procname;
1896 new->mode = 0555;
1897
1898 *prevp = new;
1899 prevp = &new->child;
1900
1901 new += 2;
1902 }
1903 *prevp = table;
1904 header->ctl_table_arg = table;
1905
1906 INIT_LIST_HEAD(&header->ctl_entry);
1907 header->used = 0;
1908 header->unregistering = NULL;
1909 header->root = root;
1910 sysctl_set_parent(NULL, header->ctl_table);
1911 header->count = 1;
1912#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1913 if (sysctl_check_table(namespaces, header->ctl_table)) {
1914 kfree(header);
1915 return NULL;
1916 }
1917#endif
1918 spin_lock(&sysctl_lock);
1919 header->set = lookup_header_set(root, namespaces);
1920 header->attached_by = header->ctl_table;
1921 header->attached_to = root_table;
1922 header->parent = &root_table_header;
1923 for (set = header->set; set; set = set->parent) {
1924 struct ctl_table_header *p;
1925 list_for_each_entry(p, &set->list, ctl_entry) {
1926 if (p->unregistering)
1927 continue;
1928 try_attach(p, header);
1929 }
1930 }
1931 header->parent->count++;
1932 list_add_tail(&header->ctl_entry, &header->set->list);
1933 spin_unlock(&sysctl_lock);
1934
1935 return header;
1936}
1937
1938/**
1939 * register_sysctl_table_path - register a sysctl table hierarchy
1940 * @path: The path to the directory the sysctl table is in.
1941 * @table: the top-level table structure
1942 *
1943 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1944 * array. A completely 0 filled entry terminates the table.
1945 *
1946 * See __register_sysctl_paths for more details.
1947 */
1948struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1949 struct ctl_table *table)
1950{
1951 return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
1952 path, table);
1953}
1954
1955/**
1956 * register_sysctl_table - register a sysctl table hierarchy
1957 * @table: the top-level table structure
1958 *
1959 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1960 * array. A completely 0 filled entry terminates the table.
1961 *
1962 * See register_sysctl_paths for more details.
1963 */
1964struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
1965{
1966 static const struct ctl_path null_path[] = { {} };
1967
1968 return register_sysctl_paths(null_path, table);
1969}
1970
1971/**
1972 * unregister_sysctl_table - unregister a sysctl table hierarchy
1973 * @header: the header returned from register_sysctl_table
1974 *
1975 * Unregisters the sysctl table and all children. proc entries may not
1976 * actually be removed until they are no longer used by anyone.
1977 */
1978void unregister_sysctl_table(struct ctl_table_header * header)
1979{
1980 might_sleep();
1981
1982 if (header == NULL)
1983 return;
1984
1985 spin_lock(&sysctl_lock);
1986 start_unregistering(header);
1987 if (!--header->parent->count) {
1988 WARN_ON(1);
1989 kfree_rcu(header->parent, rcu);
1990 }
1991 if (!--header->count)
1992 kfree_rcu(header, rcu);
1993 spin_unlock(&sysctl_lock);
1994}
1995
1996int sysctl_is_seen(struct ctl_table_header *p)
1997{
1998 struct ctl_table_set *set = p->set;
1999 int res;
2000 spin_lock(&sysctl_lock);
2001 if (p->unregistering)
2002 res = 0;
2003 else if (!set->is_seen)
2004 res = 1;
2005 else
2006 res = set->is_seen(set);
2007 spin_unlock(&sysctl_lock);
2008 return res;
2009}
2010
2011void setup_sysctl_set(struct ctl_table_set *p,
2012 struct ctl_table_set *parent,
2013 int (*is_seen)(struct ctl_table_set *))
2014{
2015 INIT_LIST_HEAD(&p->list);
2016 p->parent = parent ? parent : &sysctl_table_root.default_set;
2017 p->is_seen = is_seen;
2018}
2019
2020#else /* !CONFIG_SYSCTL */
2021struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
2022{
2023 return NULL;
2024}
2025
2026struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
2027 struct ctl_table *table)
2028{
2029 return NULL;
2030}
2031
2032void unregister_sysctl_table(struct ctl_table_header * table)
2033{
2034}
2035
2036void setup_sysctl_set(struct ctl_table_set *p,
2037 struct ctl_table_set *parent,
2038 int (*is_seen)(struct ctl_table_set *))
2039{
2040}
2041
2042void sysctl_head_put(struct ctl_table_header *head)
2043{
2044}
2045
2046#endif /* CONFIG_SYSCTL */ 1558#endif /* CONFIG_SYSCTL */
2047 1559
2048/* 1560/*
@@ -2884,9 +2396,7 @@ int proc_do_large_bitmap(struct ctl_table *table, int write,
2884 } 2396 }
2885 } 2397 }
2886 2398
2887 while (val_a <= val_b) 2399 bitmap_set(tmp_bitmap, val_a, val_b - val_a + 1);
2888 set_bit(val_a++, tmp_bitmap);
2889
2890 first = 0; 2400 first = 0;
2891 proc_skip_char(&kbuf, &left, '\n'); 2401 proc_skip_char(&kbuf, &left, '\n');
2892 } 2402 }
@@ -2929,8 +2439,7 @@ int proc_do_large_bitmap(struct ctl_table *table, int write,
2929 if (*ppos) 2439 if (*ppos)
2930 bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len); 2440 bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
2931 else 2441 else
2932 memcpy(bitmap, tmp_bitmap, 2442 bitmap_copy(bitmap, tmp_bitmap, bitmap_len);
2933 BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long));
2934 } 2443 }
2935 kfree(tmp_bitmap); 2444 kfree(tmp_bitmap);
2936 *lenp -= left; 2445 *lenp -= left;
@@ -3008,6 +2517,3 @@ EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
3008EXPORT_SYMBOL(proc_dostring); 2517EXPORT_SYMBOL(proc_dostring);
3009EXPORT_SYMBOL(proc_doulongvec_minmax); 2518EXPORT_SYMBOL(proc_doulongvec_minmax);
3010EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax); 2519EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
3011EXPORT_SYMBOL(register_sysctl_table);
3012EXPORT_SYMBOL(register_sysctl_paths);
3013EXPORT_SYMBOL(unregister_sysctl_table);