The new function can be used to update bitmaps via /proc. Bits can be
set by writing positive values in the file and cleared by writing
negative values (e.g. 0 2 will set bits 1 and 3, -0 -2 will clear
them). Reading will show only the set bits.
Signed-off-by: Octavian Purdila <opurdila@xxxxxxxxxxx>
Cc: WANG Cong <amwang@xxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
---
include/linux/sysctl.h | 2 +
kernel/sysctl.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 78 insertions(+), 0 deletions(-)
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 9f236cd..ba89bf2 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -985,6 +985,8 @@ extern int proc_doulongvec_minmax(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
void __user *, size_t *, loff_t *);
+extern int proc_dobitmap(struct ctl_table *, int,
+ void __user *, size_t *, loff_t *);
/*
* Register a set of sysctl names by calling register_sysctl_table
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b0f9618..b8959f4 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2596,6 +2596,82 @@ static int proc_do_cad_pid(struct ctl_table *table, int write,
return 0;
}
+/**
+ * proc_dobitmap - read/write from/to a bitmap
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ * @ppos: the current position in the file