git: 64de7b789b3d - stable/14 - posix shm: add shm_get_path(9)

The branch stable/14 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=64de7b789b3d9fb03dfac93fa8c3ba6fa27bcd82

commit 64de7b789b3d9fb03dfac93fa8c3ba6fa27bcd82
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2024-10-07 01:44:49 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2024-10-15 14:50:17 +0000

    posix shm: add shm_get_path(9)
    
    (cherry picked from commit bda73e441f2576de5ad00856d758354c299a3f75)
---
 sys/kern/uipc_shm.c | 31 +++++++++++++++++++++++++++++++
 sys/sys/mman.h      |  1 +
 2 files changed, 32 insertions(+)

diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c
index 52a569931b01..8334d7eb3264 100644
--- a/sys/kern/uipc_shm.c
+++ b/sys/kern/uipc_shm.c
@@ -2196,3 +2196,34 @@ sys_shm_open2(struct thread *td, struct shm_open2_args *uap)
 	return (kern_shm_open2(td, uap->path, uap->flags, uap->mode,
 	    uap->shmflags, NULL, uap->name));
 }
+
+int
+shm_get_path(struct vm_object *obj, char *path, size_t sz)
+{
+	struct shmfd *shmfd;
+	int error;
+
+	error = 0;
+	shmfd = NULL;
+	sx_slock(&shm_dict_lock);
+	VM_OBJECT_RLOCK(obj);
+	if ((obj->flags & OBJ_POSIXSHM) == 0) {
+		error = EINVAL;
+	} else {
+		if (obj->type == shmfd_pager_type)
+			shmfd = obj->un_pager.swp.swp_priv;
+		else if (obj->type == OBJT_PHYS)
+			shmfd = obj->un_pager.phys.phys_priv;
+		if (shmfd == NULL) {
+			error = ENXIO;
+		} else {
+			strlcpy(path, shmfd->shm_path == NULL ? "anon" :
+			    shmfd->shm_path, sz);
+		}
+	}
+	if (error != 0)
+		path[0] = '\0';
+	VM_OBJECT_RUNLOCK(obj);
+	sx_sunlock(&shm_dict_lock);
+	return (error);
+}
diff --git a/sys/sys/mman.h b/sys/sys/mman.h
index 7eb38a5f59d0..36973b941e61 100644
--- a/sys/sys/mman.h
+++ b/sys/sys/mman.h
@@ -310,6 +310,7 @@ void	shm_drop(struct shmfd *shmfd);
 int	shm_dotruncate(struct shmfd *shmfd, off_t length);
 bool	shm_largepage(struct shmfd *shmfd);
 void	shm_remove_prison(struct prison *pr);
+int	shm_get_path(struct vm_object *obj, char *path, size_t sz);
 
 extern struct fileops shm_ops;