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keyctl_update(3) [debian man page]

KEYCTL_UPDATE(3)					    Linux Key Management Calls						  KEYCTL_UPDATE(3)

NAME
keyctl_update - Update a key SYNOPSIS
#include <keyutils.h> long keyctl_update(key_serial_t key, const char *payload, size_t plen); DESCRIPTION
keyctl_update() updates the payload of a key if the key type permits it. The caller must have write permission on a key to be able update it. payload and plen specify the data for the new payload. payload may be NULL and plen may be zero if the key type permits that. The key type may reject the data if it's in the wrong format or in some other way invalid. RETURN VALUE
On success keyctl_update() returns 0. On error, the value -1 will be returned and errno will have been set to an appropriate error. ERRORS
ENOKEY The key specified is invalid. EKEYEXPIRED The key specified has expired. EKEYREVOKED The key specified had been revoked. EINVAL The payload data was invalid. ENOMEM Insufficient memory to store the new payload. EDQUOT The key quota for this user would be exceeded by increasing the size of the key to accommodate the new payload. EACCES The key exists, but is not writable by the calling process. EOPNOTSUPP The key type does not support the update operation on its keys. LINKING
This is a library function that can be found in libkeyutils. When linking, -lkeyutils should be specified to the linker. SEE ALSO
keyctl(1), add_key(2), keyctl(2), request_key(2), keyctl_get_keyring_ID(3), keyctl_join_session_keyring(3), keyctl_revoke(3), keyctl_chown(3), keyctl_setperm(3), keyctl_describe(3), keyctl_clear(3), keyctl_link(3), keyctl_unlink(3), keyctl_search(3), keyctl_read(3), keyctl_instantiate(3), keyctl_negate(3), keyctl_set_reqkey_keyring(3), keyctl_set_timeout(3), keyctl_assume_authority(3), keyctl_describe_alloc(3), keyctl_read_alloc(3), request-key(8) Linux 4 May 2006 KEYCTL_UPDATE(3)

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KEYCTL_READ(3)						    Linux Key Management Calls						    KEYCTL_READ(3)

NAME
keyctl_read - Read a key SYNOPSIS
#include <keyutils.h> long keyctl_read(key_serial_t key, char *buffer, size_tbuflen); long keyctl_read_alloc(key_serial_t key, char **_buffer); DESCRIPTION
keyctl_read() reads the payload of a key if the key type supports it. 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, the full size of the payload will be returned, and no copy will take place. 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. READING KEYRINGS
This call can be used to list the contents of a keyring. The data is presented to the user as an array of key_serial_t values, each of which corresponds to a key to which the keyring holds a link. 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 dif- ferent word sizes, though the byte-ordering is as appropriate for the kernel. RETURN VALUE
On success keyctl_read() returns the amount of data placed into the buffer. If the buffer was too small, then the size of buffer required will be returned, but no data will be transferred. On error, the value -1 will be returned and errno will have been set to an appropriate error. On success keyctl_read_alloc() returns the amount of data in the buffer. On error, the value -1 will be returned and errno will have been set to an appropriate error. ERRORS
ENOKEY The key specified is invalid. EKEYEXPIRED The key specified has expired. EKEYREVOKED The key specified had been revoked. EACCES The key exists, but is not readable by the calling process. EOPNOTSUPP The key type does not support reading of the payload data. LINKING
This is a library function that can be found in libkeyutils. When linking, -lkeyutils should be specified to the linker. SEE ALSO
keyctl(1), add_key(2), keyctl(2), request_key(2), keyctl_get_keyring_ID(3), keyctl_join_session_keyring(3), keyctl_update(3), keyctl_revoke(3), keyctl_chown(3), keyctl_setperm(3), keyctl_describe(3), keyctl_clear(3), keyctl_link(3), keyctl_unlink(3), keyctl_search(3), keyctl_instantiate(3), keyctl_negate(3), keyctl_set_reqkey_keyring(3), keyctl_set_timeout(3), keyctl_assume_authority(3), keyctl_describe_alloc(3), request-key(8) Linux 4 May 2006 KEYCTL_READ(3)

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