Man page 9 : proc_dostring

proc_dostring - read a string sysctl

int proc_dostring(struct ctl_table *  table , int  write , void __user *  buffer , size_t *  lenp , loff_t *  ppos );

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

Reads/writes a string from/to the user buffer. If the kernel buffer provided is not large enough to hold the string, the string is truncated. The copied string is NULL-terminated. If the string is being read by the user process, it is copied and a newline Aq\nAq is added. It is truncated if the buffer is not large enough.

Returns 0 on success.