NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SUMMARY OF TRUSTED SOLARIS CHANGES | SEE ALSO
#include <sys/msg.h>int msgget(key_t key, int msgflg);
#include <sys/tsol/ipcl.h>int msggetl(key_t key, int msgflg, const bslabel_ t *slabel);
A message queue is identified by a unique combination of key and sensitivity label. This qualification of keys by sensitivity labels allows applications that use message queues to be run at multiple process sensitivity labels without inadvertently sharing data.
msgget() returns the message-queue identifier associated with the union of key and the sensitivity label of the calling process.
msggetl() returns the message-queue identifier associated with the union of key and slabel. If the value of slabel does not match the sensitivity label of the calling process, then the effective privilege set of the process
must contain PRIV_IPC_MAC_READ
or PRIV_IPC_MAC_WRITE
.
If discretionary read/write access as specified by the low-order 9 bits of msgflg is denied to the calling process, msgget() and msggetl() require one or both of these privileges: PRIV_IPC_DAC_READ
and PRIV_IPC_DAC_WRITE
.
A message-queue identifier and associated message queue and data structure (see intro(2)) are created for key if one of the following is true:
key is IPC_PRIVATE.
key does not already have a message queue identifier associated with it, and (msgflg&IPC_CREAT) is true.
On creation, the data structure associated with the new message queue identifier is initialized as follows:
msg_perm.cuid, msg_perm.uid, msg_perm.cgid, and msg_perm.gid are set to the effective user ID and effective group ID, respectively, of the calling process.
The low-order 9 bits of msg_perm.mode are set to the low-order 9 bits of msgflg.
msg_qnum, msg_lspid, msg_lrpid, msg_stime, and msg_rtime are set to 0.
msg_ctime is set to the current time.
msg_qbytes is set to the system limit.
The sensitivity label on the message-queue internal is set either to the sensitivity label of the process or to slabel, depending on which interface was used.
Upon successful completion, a non-negative integer representing a message queue identifier is returned. Otherwise, -1 is returned and errno is set to indicate the error.
The msgget() function will fail if:
A semaphore-structure identifier exists for the union of key and sensitivity label, but operation permission [see intro(2)] as specified by the low-order 9 bits of semflg would not be granted; or the sensitivity label check did not pass, and the calling process does not have the appropriate privilege override(s) in its set of effective privileges.
A message queue identifier exists for key but (msgflg&IPC_CREAT) and (msgflg&IPC_EXCL) are both true.
slabel points to an illegal address.
The label to which slabel points is not a valid sensitivity label.
A message queue identifier does not exist for the union of key and sensitivity label; and (msgflg&IPC_CREAT) is false.
A message queue identifier is to be created but the system-imposed limit on the maximum number of allowed message queue identifiers system wide would be exceeded.
Appropriate privilege is required to override access checks.
Sensitivity labels are used together with key to determine message-queue identifiers.
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SUMMARY OF TRUSTED SOLARIS CHANGES | SEE ALSO