request_key   Début   Suivant   Sommaire   Préc.page.lue   Accueil
Section: Linux Key Management Calls (2)
Updated: 4 May 2006
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NAME   Début   Précédent   Suivant   Sommaire   Préc.page.lue   Accueil
request_key - Request a key from the kernel's key management facility  



SYNOPSIS   Début   Précédent   Suivant   Sommaire   Préc.page.lue   Accueil
#include <keyutils.h>

key_serial_t request_key(const char *type, const char *description,
const char *callout_info, key_serial_t keyring);
 



DESCRIPTION   Début   Précédent   Suivant   Sommaire   Préc.page.lue   Accueil
request_key() asks the kernel to find a key of the given type that matches the specified description and, if successful, to attach it to the nominated keyring and to return its serial number. request_key() first recursively searches all the keyrings attached to the calling process in the order thread-specific keyring, process-specific keyring and then session keyring for a matching key. If request_key() is called from a program invoked by request_key() on behalf of some other process to generate a key, then the keyrings of that other process will be searched next, using that other process's UID, GID, groups and security context to control access. The keys in each keyring searched are checked for a match before any child keyrings are recursed into. Only keys that are searchable for the caller may be found, and only searchable keyrings may be searched. If the key is not found then, if callout_info is set, this function will attempt to look further afield. In such a case, the callout_info is passed to a userspace service such as /sbin/request-key to generate the key. If that is unsuccessful also, then an error will be returned, and a temporary negative key will be installed in the nominated keyring. This will expire after a few seconds, but will cause subsequent calls to request_key() to fail until it does. The keyring serial number may be that of a valid keyring to which the caller has write permission, or it may be a special keyring ID:
KEY_SPEC_THREAD_KEYRING
This specifies the caller's thread-specific keyring.
KEY_SPEC_PROCESS_KEYRING
This specifies the caller's process-specific keyring.
KEY_SPEC_SESSION_KEYRING
This specifies the caller's session-specific keyring.
KEY_SPEC_USER_KEYRING
This specifies the caller's UID-specific keyring.
KEY_SPEC_USER_SESSION_KEYRING
This specifies the caller's UID-session keyring. If a key is created, no matter whether it's a valid key or a negative key, it will displace any other key of the same type and description from the destination keyring.
 



RETURN VALUE   Début   Précédent   Suivant   Sommaire   Préc.page.lue   Accueil
On success request_key() returns the serial number of the key it found. On error, the value -1 will be returned and errno will have been set to an appropriate error.  



ERRORS   Début   Précédent   Suivant   Sommaire   Préc.page.lue   Accueil
ENOKEY
No matching key was found.
EKEYEXPIRED
An expired key was found, but no replacement could be obtained.
EKEYREVOKED
A revoked key was found, but no replacement could be obtained.
EKEYREJECTED
The attempt to generate a new key was rejected.
ENOMEM
Insufficient memory to create a key.
EINTR
The request was interrupted by a signal.
EDQUOT
The key quota for this user would be exceeded by creating this key or linking it to the keyring.
EACCES
The keyring wasn't available for modification by the user.
 



LINKING   Début   Précédent   Suivant   Sommaire   Préc.page.lue   Accueil
Although this is a Linux system call, it is not present in libc but can be found rather in libkeyutils. When linking, -lkeyutils should be specified to the linker.  



SEE ALSO   Début   Précédent   Suivant   Sommaire   Préc.page.lue   Accueil
keyctl(1), add_key(2), keyctl(2), request-key(8)


 



Sommaire   Début   Suivant   Sommaire   Préc.page.lue   Accueil
NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
LINKING
SEE ALSO

Table des mots clés   Début   Suivant   Sommaire   Préc.page.lue   Accueil
EACCESERRORS
EDQUOTERRORS
EINTRERRORS
EKEYEXPIREDERRORS
EKEYREJECTEDERRORS
EKEYREVOKEDERRORS
ENOKEYERRORS
ENOMEMERRORS
KEY_SPEC_PROCESS_KEYRINGDESCRIPTION
KEY_SPEC_SESSION_KEYRINGDESCRIPTION
KEY_SPEC_THREAD_KEYRINGDESCRIPTION
KEY_SPEC_USER_KEYRINGDESCRIPTION
KEY_SPEC_USER_SESSION_KEYRINGDESCRIPTION



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