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authorjhb <jhb@FreeBSD.org>2008-01-08 21:58:16 +0000
committerjhb <jhb@FreeBSD.org>2008-01-08 21:58:16 +0000
commit8cd9437636744162d1427275b2fe66cf8ccef25c (patch)
tree49b07dc757aae71e0a64eb4939cde4037af60a24 /sys/security/mac_stub
parent23d78439c96372baa4a3c2847df65f8e11455ae7 (diff)
downloadFreeBSD-src-8cd9437636744162d1427275b2fe66cf8ccef25c.zip
FreeBSD-src-8cd9437636744162d1427275b2fe66cf8ccef25c.tar.gz
Add a new file descriptor type for IPC shared memory objects and use it to
implement shm_open(2) and shm_unlink(2) in the kernel: - Each shared memory file descriptor is associated with a swap-backed vm object which provides the backing store. Each descriptor starts off with a size of zero, but the size can be altered via ftruncate(2). The shared memory file descriptors also support fstat(2). read(2), write(2), ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared memory file descriptors. - shm_open(2) and shm_unlink(2) are now implemented as system calls that manage shared memory file descriptors. The virtual namespace that maps pathnames to shared memory file descriptors is implemented as a hash table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash of the pathname. - As an extension, the constant 'SHM_ANON' may be specified in place of the path argument to shm_open(2). In this case, an unnamed shared memory file descriptor will be created similar to the IPC_PRIVATE key for shmget(2). Note that the shared memory object can still be shared among processes by sharing the file descriptor via fork(2) or sendmsg(2), but it is unnamed. This effectively serves to implement the getmemfd() idea bandied about the lists several times over the years. - The backing store for shared memory file descriptors are garbage collected when they are not referenced by any open file descriptors or the shm_open(2) virtual namespace. Submitted by: dillon, peter (previous versions) Submitted by: rwatson (I based this on his version) Reviewed by: alc (suggested converting getmemfd() to shm_open())
Diffstat (limited to 'sys/security/mac_stub')
-rw-r--r--sys/security/mac_stub/mac_stub.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/sys/security/mac_stub/mac_stub.c b/sys/security/mac_stub/mac_stub.c
index 50463a0..165e7bb 100644
--- a/sys/security/mac_stub/mac_stub.c
+++ b/sys/security/mac_stub/mac_stub.c
@@ -578,6 +578,53 @@ stub_posixsem_create(struct ucred *cred, struct ksem *ks,
}
static int
+stub_posixshm_check_mmap(struct ucred *cred, struct shmfd *shmfd,
+ struct label *shmlabel, int prot, int flags)
+{
+
+ return (0);
+}
+
+static int
+stub_posixshm_check_open(struct ucred *cred, struct shmfd *shmfd,
+ struct label *shmlabel)
+{
+
+ return (0);
+}
+
+static int
+stub_posixshm_check_stat(struct ucred *active_cred, struct ucred *file_cred,
+ struct shmfd *shmfd, struct label *shmlabel)
+{
+
+ return (0);
+}
+
+static int
+stub_posixshm_check_truncate(struct ucred *active_cred,
+ struct ucred *file_cred, struct shmfd *shmfd, struct label *shmlabel)
+{
+
+ return (0);
+}
+
+static int
+stub_posixshm_check_unlink(struct ucred *cred, struct shmfd *shmfd,
+ struct label *shmlabel)
+{
+
+ return (0);
+}
+
+static void
+stub_posixshm_create(struct ucred *cred, struct shmfd *shmfd,
+ struct label *shmlabel)
+{
+
+}
+
+static int
stub_priv_check(struct ucred *cred, int priv)
{
@@ -1550,6 +1597,15 @@ static struct mac_policy_ops stub_ops =
.mpo_posixsem_destroy_label = stub_destroy_label,
.mpo_posixsem_init_label = stub_init_label,
+ .mpo_posixshm_check_mmap = stub_posixshm_check_mmap,
+ .mpo_posixshm_check_open = stub_posixshm_check_open,
+ .mpo_posixshm_check_stat = stub_posixshm_check_stat,
+ .mpo_posixshm_check_truncate = stub_posixshm_check_truncate,
+ .mpo_posixshm_check_unlink = stub_posixshm_check_unlink,
+ .mpo_posixshm_create = stub_posixshm_create,
+ .mpo_posixshm_destroy_label = stub_destroy_label,
+ .mpo_posixshm_init_label = stub_init_label,
+
.mpo_priv_check = stub_priv_check,
.mpo_priv_grant = stub_priv_grant,
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