GETPEERUCRED(3C)GETPEERUCRED(3C)NAMEgetpeerucred - get connected socket or stream peer's credentials
int getpeerucred(int fd, ucred_t **ucred);
The getpeerucred() function returns the credentials of the peer end‐
point of a connection-oriented socket (SOCK_STREAM) or stream fd at the
time the endpoint was created or the connection was established. A
process that initiates a connection retrieves the credentials of its
peer at the time the peer's endpoint was created. A process that lis‐
tens for connections retrieves the credentials of the peer at the time
the peer initiated the connection.
When successful, getpeerucred() stores the pointer to a freshly allo‐
cated ucred_t in the memory location pointed to by the ucred argument
if that memory location contains the null pointer. If the memory loca‐
tion is non-null, it will reuse the existing ucred_t.
When ucred is no longer needed, a credential allocated by getpeeru‐
cred() should be freed with ucred_free(3C).
It is possible that all fields of the ucred_t are not available to all
peer endpoints and all callers.
Upon successful completion, getpeerucred() returns 0. Otherwise, it
returns −1 and errno is set to indicate the error.
The getpeerucred() function will fail if:
There is not enough memory available to allocate sufficient
memory to hold the user credential. The application can try
The fd argument is not a valid file descriptor.
The pointer location pointed to by the ucred_t ** argument
points to an invalid, non-null address.
The socket is connected but the peer credentials are
The physical limits of the system are exceeded by the mem‐
ory allocation needed to hold the user credential.
The socket or stream is not connected or the stream's peer
This operation is not supported on this file descriptor.
See attributes(5) for descriptions of the following attributes:
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
│Interface Stability │ Evolving │
│MT-Level │ MT-Safe │
SEE ALSOdoor_ucred(3C), ucred_get(3C), attributes(5), connld(7M)NOTES
The system currently supports both sides of connection endpoints for
local AF_UNIX, AF_INET, and AF_INET6 sockets, /dev/tcp, /dev/ticots,
and /dev/ticotsord XTI/TLI connections, and pipe file descriptors sent
using I_SENDFD as a result of the open of a named pipe with the
"connld" module pushed.
May 26, 2004 GETPEERUCRED(3C)