|KEYCTL_READ(3)||Linux Key Management Calls||KEYCTL_READ(3)|
#include <keyutils.h> long keyctl_read(key_serial_t key, char *buffer, size_t buflen); long keyctl_read_alloc(key_serial_t key, void **_buffer);
The caller must have read permission on a key to be able to read it.
buffer and buflen specify the buffer into which the payload data will be placed. If the buffer is too small, then the full size of the payload will be returned, and the contents of the buffer may be overwritten in some undefined way.
keyctl_read_alloc() is similar to keyctl_read() except that it allocates a buffer big enough to hold the payload data and places the data in it. If successful, a pointer to the buffer is placed in *_buffer. The caller must free the buffer.
keyctl_read_alloc() adds a NUL character after the data it retrieves, though this is not counted in the size value it returns.
The size of the keyring will be sizeof(key_serial_t) multiplied by the number of keys. The size of key_serial_t is invariant across different word sizes, though the byte-ordering is as appropriate for the kernel.
On success keyctl_read_alloc() returns the amount of data in the buffer.
On error, both functions set errno to an appropriate code and return the value -1.
- The key specified is invalid.
- The key specified has expired.
- The key specified had been revoked.
- The key exists, but is not readable by the calling process.
- The key type does not support reading of the payload data.
|21 Feb 2014||Linux|