Make four groups in the sysctl header and document each group with an example of how to use them. 1. proc_handler : All functions that can be passed to the proc_handler pointer in ctl_table 2. proc handler aggregators: Functions to create proc handlers with custom converters 3. bi-directional converters: Functions to create read/write custom converters. Can be passed to proc handler aggregators 4. uni-directional converters: Functions to create read or write custom converters. Can be passed as args to bi-directional converters Use just one naming convention in the declarations: 'write' becomes 'dir' and 'buffer' becomes 'buf'. Signed-off-by: Joel Granados --- include/linux/sysctl.h | 128 +++++++++++++++++++++++++++++++++---------------- 1 file changed, 87 insertions(+), 41 deletions(-) diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 8f8e357b1f4d377a0891fbc85d34073cd30469b1..ad268dfd9e79f5540a4a85a9a439819fb3172640 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -74,63 +74,109 @@ extern const int sysctl_vals[]; extern const unsigned long sysctl_long_vals[]; -typedef int proc_handler(const struct ctl_table *ctl, int write, void *buffer, - size_t *lenp, loff_t *ppos); - -int proc_dostring(const struct ctl_table *, int, void *, size_t *, loff_t *); -int proc_dobool(const struct ctl_table *table, int write, void *buffer, - size_t *lenp, loff_t *ppos); +typedef int proc_handler(const struct ctl_table *ctl, int dir, void *buf, + size_t *lenp, loff_t *ppos); -int proc_dointvec(const struct ctl_table *, int, void *, size_t *, loff_t *); -int proc_dointvec_minmax(const struct ctl_table *table, int dir, void *buffer, +/* proc_handler functions */ +int proc_dostring(const struct ctl_table *ctl, int dir, void *buf, size_t *lenp, + loff_t *ppos); +int proc_dobool(const struct ctl_table *ctl, int dir, void *buf, size_t *lenp, + loff_t *ppos); +int proc_dointvec(const struct ctl_table *ctl, int dir, void *buf, size_t *lenp, + loff_t *ppos); +int proc_dointvec_minmax(const struct ctl_table *ctl, int dir, void *buf, size_t *lenp, loff_t *ppos); -int proc_dointvec_conv(const struct ctl_table *table, int dir, void *buffer, +int proc_douintvec(const struct ctl_table *ctl, int dir, void *buf, size_t *lenp, + loff_t *ppos); +int proc_douintvec_minmax(const struct ctl_table *ctl, int dir, void *buf, + size_t *lenp, loff_t *ppos); +int proc_dou8vec_minmax(const struct ctl_table *ctl, int dir, void *buf, + size_t *lenp, loff_t *ppos); +int proc_doulongvec_minmax(const struct ctl_table *ctl, int dir, void *buf, + size_t *lenp, loff_t *ppos); +int proc_do_large_bitmap(const struct ctl_table *ctl, int dir, void *buf, + size_t *lenp, loff_t *ppos); +int proc_do_static_key(const struct ctl_table *ctl, int dir, void *buf, + size_t *lenp, loff_t *ppos); + +/* + * proc_handler aggregators + * + * Create a proc_handler with a custom converter. Use when the user space + * value is a transformation of the kernel value. Cannot be passed as + * proc_handlers. + * + * Example of creating your custom proc handler: + * int custom_converter(bool *negp, ulong *u_ptr, uint *k_ptr, + * int dir, const struct ctl_table *ctl) {...} + * int custom_proc_handler(const struct ctl_table *ctl, int dir, + * void *buf, size_t *lenp, loff_t *ppos + * { return proc_dointvec_conv(ctl, dir, buf, lenp, ppos, custom_converter); } + */ +int proc_dointvec_conv(const struct ctl_table *ctl, int dir, void *buf, size_t *lenp, loff_t *ppos, int (*conv)(bool *negp, unsigned long *u_ptr, int *k_ptr, - int dir, const struct ctl_table *table)); -int proc_int_k2u_conv_kop(ulong *u_ptr, const int *k_ptr, bool *negp, - ulong (*k_ptr_op)(const ulong)); -int proc_int_u2k_conv_uop(const ulong *u_ptr, int *k_ptr, const bool *negp, - ulong (*u_ptr_op)(const ulong)); + int dir, const struct ctl_table *ctl)); +int proc_douintvec_conv(const struct ctl_table *ctl, int dir, void *buf, + size_t *lenp, loff_t *ppos, + int (*conv)(bool *negp, ulong *u_ptr, uint *k_ptr, + int dir, const struct ctl_table *ctl)); +int proc_doulongvec_minmax_conv(const struct ctl_table *ctl, int dir, void *buf, + size_t *lenp, loff_t *ppos, + int (*conv)(bool *negp, ulong *u_ptr, ulong *k_ptr, + int dir, const struct ctl_table *ctl)); + +/* + * bi-directional converter functions + * + * Specify the converter function for both directions (user to kernel & kernel + * to user). Use when you want to change the value of the variable before + * assignment. Used to create custom proc_handler aggregators. + * + * Example of creating your custom bi-directional converter: + * int custom_u2k(ulong *u_ptr, const uint *k_ptr) { ... } + * int custom_converter(bool *negp, ulong *u_ptr, uint *k_ptr, + * int dir, const struct ctl_table *ctl) + * { return proc_uint_conv(u_ptr, k_ptr, dir, ctl, true, + * custom_u2k, proc_uint_k2u_conv} + */ int proc_int_conv(bool *negp, ulong *u_ptr, int *k_ptr, int dir, const struct ctl_table *tbl, bool k_ptr_range_check, int (*user_to_kern)(const bool *negp, const ulong *u_ptr, int *k_ptr), int (*kern_to_user)(bool *negp, ulong *u_ptr, const int *k_ptr)); - -int proc_douintvec(const struct ctl_table *, int, void *, size_t *, loff_t *); -int proc_douintvec_minmax(const struct ctl_table *table, int write, void *buffer, - size_t *lenp, loff_t *ppos); -int proc_douintvec_conv(const struct ctl_table *table, int write, void *buffer, - size_t *lenp, loff_t *ppos, - int (*conv)(bool *negp, ulong *lvalp, uint *valp, - int write, const struct ctl_table *table)); -int proc_uint_k2u_conv(ulong *u_ptr, const uint *k_ptr); -int proc_uint_u2k_conv_uop(const ulong *u_ptr, uint *k_ptr, - ulong (*u_ptr_op)(const ulong)); int proc_uint_conv(ulong *u_ptr, uint *k_ptr, int dir, const struct ctl_table *tbl, bool k_ptr_range_check, int (*user_to_kern)(const ulong *u_ptr, uint *k_ptr), int (*kern_to_user)(ulong *u_ptr, const uint *k_ptr)); - -int proc_dou8vec_minmax(const struct ctl_table *table, int write, void *buffer, - size_t *lenp, loff_t *ppos); -int proc_doulongvec_minmax(const struct ctl_table *, int, void *, size_t *, loff_t *); -int proc_doulongvec_minmax_conv(const struct ctl_table *table, int dir, - void *buffer, size_t *lenp, loff_t *ppos, - int (*conv)(bool *negp, ulong *u_ptr, ulong *k_ptr, - int dir, const struct ctl_table *table)); -int proc_do_large_bitmap(const struct ctl_table *, int, void *, size_t *, loff_t *); -int proc_do_static_key(const struct ctl_table *table, int write, void *buffer, - size_t *lenp, loff_t *ppos); - -int proc_ulong_u2k_conv_uop(const ulong *u_ptr, ulong *k_ptr, - ulong (*u_ptr_op)(const ulong)); -int proc_ulong_k2u_conv_kop(ulong *u_ptr, const ulong *k_ptr, - ulong (*k_ptr_op)(const ulong)); int proc_ulong_conv(ulong *u_ptr, ulong *k_ptr, int dir, const struct ctl_table *tbl, bool k_ptr_range_check, int (*user_to_kern)(const ulong *u_ptr, ulong *k_ptr), int (*kern_to_user)(ulong *u_ptr, const ulong *k_ptr)); + +/* + * uni-directional converter functions + * + * Specify the converter function for one directions (user to kernel or + * kernel to user). Use to call the actual value conversion. Used to Create + * bi-directional converters. + * + * Example of creating a uni-directional converter: + * ulong op(const ulong val) { ... } + * int custom_unidir_conv(ulong *u_ptr, const uint *k_ptr) + * { return proc_uint_k2u_conv_kop(u_ptr, k_ptr, op); } + */ +int proc_int_k2u_conv_kop(ulong *u_ptr, const int *k_ptr, bool *negp, + ulong (*k_ptr_op)(const ulong)); +int proc_int_u2k_conv_uop(const ulong *u_ptr, int *k_ptr, const bool *negp, + ulong (*u_ptr_op)(const ulong)); +int proc_uint_k2u_conv(ulong *u_ptr, const uint *k_ptr); +int proc_uint_u2k_conv_uop(const ulong *u_ptr, uint *k_ptr, + ulong (*u_ptr_op)(const ulong)); +int proc_ulong_u2k_conv_uop(const ulong *u_ptr, ulong *k_ptr, + ulong (*u_ptr_op)(const ulong)); +int proc_ulong_k2u_conv_kop(ulong *u_ptr, const ulong *k_ptr, + ulong (*k_ptr_op)(const ulong)); + /* * Register a set of sysctl names by calling register_sysctl * with an initialised array of struct ctl_table's. -- 2.50.1