include/linux/sysctl.h

/* */
   1 /*
   2  * sysctl.h: General linux system control interface
   3  *
   4  * Begun 24 March 1995, Stephen Tweedie
   5  */
   6 
   7 #include <linux/lists.h>
   8 
   9 #ifndef _LINUX_SYSCTL_H
  10 #define _LINUX_SYSCTL_H
  11 
  12 #define CTL_MAXNAME 10
  13 
  14 struct __sysctl_args {
  15         int *name;
  16         int nlen;
  17         void *oldval;
  18         size_t *oldlenp;
  19         void *newval;
  20         size_t newlen;
  21         unsigned long __unused[4];
  22 };
  23 
  24 /* Define sysctl names first */
  25 
  26 /* Top-level names: */
  27 
  28 /* For internal pattern-matching use only: */
  29 #ifdef __KERNEL__
  30 #define CTL_ANY         -1      /* Matches any name */
  31 #define CTL_NONE                0
  32 #endif
  33 
  34 #define CTL_KERN        1       /* General kernel info and control */
  35 #define CTL_VM          2       /* VM management */
  36 #define CTL_NET         3       /* Networking */
  37 #define CTL_PROC        4       /* Process info */
  38 #define CTL_FS          5       /* Filesystems */
  39 #define CTL_DEBUG       6       /* Debugging */
  40 #define CTL_DEV         7       /* Devices */
  41 #define CTL_MAXID       8
  42 
  43 /* CTL_KERN names: */
  44 #define KERN_OSTYPE     1       /* string: system version */
  45 #define KERN_OSRELEASE  2       /* string: system release */
  46 #define KERN_OSREV      3       /* int: system revision */
  47 #define KERN_VERSION    4       /* string: compile time info */
  48 #define KERN_SECUREMASK 5       /* struct: maximum rights mask */
  49 #define KERN_PROF       6       /* table: profiling information */
  50 #define KERN_NODENAME   7
  51 #define KERN_DOMAINNAME 8
  52 #define KERN_NRINODE    9
  53 #define KERN_MAXINODE   10
  54 #define KERN_NRFILE     11
  55 #define KERN_MAXFILE    12
  56 #define KERN_MAXID      13
  57 #define KERN_SECURELVL  14      /* int: system security level */
  58 
  59 /* CTL_VM names: */
  60 #define VM_SWAPCTL      1       /* struct: Set vm swapping control */
  61 #define VM_KSWAPD       2       /* struct: control background pagout */
  62 #define VM_FREEPG       3       /* struct: Set free page thresholds */
  63 #define VM_MAXID        4
  64 
  65 /* CTL_NET names: */
  66 
  67 /* CTL_PROC names: */
  68 
  69 /* CTL_FS names: */
  70 
  71 /* CTL_DEBUG names: */
  72 
  73 /* CTL_DEV names: */
  74 
  75 #ifdef __KERNEL__
  76 
  77 extern asmlinkage int sys_sysctl(struct __sysctl_args *);
  78 extern void init_sysctl(void);
  79 
  80 typedef struct ctl_table ctl_table;
  81 
  82 typedef int ctl_handler (ctl_table *table, int *name, int nlen,
  83                          void *oldval, size_t *oldlenp,
  84                          void *newval, size_t newlen, 
  85                          void **context);
  86 
  87 typedef int proc_handler (ctl_table *ctl, int write, struct file * filp,
  88                           void *buffer, size_t *lenp);
  89 
  90 extern int proc_dostring(ctl_table *, int, struct file *,
  91                          void *, size_t *);
  92 extern int proc_dointvec(ctl_table *, int, struct file *,
  93                          void *, size_t *);
  94 
  95 extern int do_sysctl (int *name, int nlen,
  96                       void *oldval, size_t *oldlenp,
  97                       void *newval, size_t newlen);
  98 
  99 extern int do_sysctl_strategy (ctl_table *table, 
 100                                int *name, int nlen,
 101                                void *oldval, size_t *oldlenp,
 102                                void *newval, size_t newlen, void ** context);
 103 
 104 extern ctl_handler sysctl_string;
 105 
 106 extern int do_string (
 107         void *oldval, size_t *oldlenp, void *newval, size_t newlen,
 108         int rdwr, char *data, size_t max);
 109 extern int do_int (
 110         void *oldval, size_t *oldlenp, void *newval, size_t newlen,
 111         int rdwr, int *data);
 112 extern int do_struct (
 113         void *oldval, size_t *oldlenp, void *newval, size_t newlen,
 114         int rdwr, void *data, size_t len);
 115 
 116 
 117 /*
 118  * Register a set of sysctl names by calling register_sysctl_table
 119  * with an initialised array of ctl_table's.  An entry with zero
 120  * ctl_name terminates the table.  table->de will be set up by the
 121  * registration and need not be initialised in advance.
 122  *
 123  * sysctl names can be mirrored automatically under /proc/sys.  The
 124  * procname supplied controls /proc naming.
 125  *
 126  * The table's mode will be honoured both for sys_sysctl(2) and
 127  * proc-fs access.
 128  *
 129  * Leaf nodes in the sysctl tree will be represented by a single file
 130  * under /proc; non-leaf nodes will be represented by directories.  A
 131  * null procname disables /proc mirroring at this node.
 132  * 
 133  * sysctl(2) can automatically manage read and write requests through
 134  * the sysctl table.  The data and maxlen fields of the ctl_table
 135  * struct enable minimal validation of the values being written to be
 136  * performed, and the mode field allows minimal authentication.
 137  * 
 138  * More sophisticated management can be enabled by the provision of a
 139  * strategy routine with the table entry.  This will be called before
 140  * any automatic read or write of the data is performed.
 141  * 
 142  * The strategy routine may return:
 143  * <0: Error occurred (error is passed to user process)
 144  * 0:  OK - proceed with automatic read or write.
 145  * >0: OK - read or write has been done by the strategy routine, so 
 146  *     return immediately.
 147  * 
 148  * There must be a proc_handler routine for any terminal nodes
 149  * mirrored under /proc/sys (non-terminals are handled by a built-in
 150  * directory handler).  Several default handlers are available to
 151  * cover common cases.
 152  */
 153 
 154 /* A sysctl table is an array of struct ctl_table: */
 155 struct ctl_table 
 156 {
 157         int ctl_name;                   /* Binary ID */
 158         const char *procname;           /* Text ID for /proc/sys, or zero */
 159         void *data;
 160         int maxlen;
 161         mode_t mode;
 162         ctl_table *child;
 163         proc_handler *proc_handler;     /* Callback for text formatting */
 164         ctl_handler *strategy;          /* Callback function for all r/w */
 165         struct proc_dir_entry *de;      /* /proc control block */
 166 };
 167 
 168 /* struct ctl_table_header is used to maintain dynamic lists of
 169    ctl_table trees. */
 170 struct ctl_table_header
 171 {
 172         ctl_table *ctl_table;
 173         DLNODE(struct ctl_table_header) ctl_entry;      
 174 };
 175 
 176 struct ctl_table_header * register_sysctl_table(ctl_table * table, 
 177                                                 int insert_at_head);
 178 void unregister_sysctl_table(struct ctl_table_header * table);
 179 
 180 #else /* __KERNEL__ */
 181 
 182 #endif /* __KERNEL__ */
 183 
 184 #endif /* _LINUX_SYSCTL_H */
/* */
root/include/linux/sysctl.h

INCLUDED FROM
