Export some more useful info about shared memory objects to userland

via procstat(1) and fstat(1):
- Change shm file descriptors to track the pathname they are associated
  with and add a shm_path() method to copy the path out to a caller-supplied
  buffer.
- Use the fo_stat() method of shared memory objects and shm_path() to
  export the path, mode, and size of a shared memory object via
  struct kinfo_file.
- Add a struct shmstat to the libprocstat(3) interface along with a
  procstat_get_shm_info() to export the mode and size of a shared memory
  object.
- Change procstat to always print out the path for a given object if it
  is valid.
- Teach fstat about shared memory objects and to display their path,
  mode, and size.

MFC after:	2 weeks

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/libprocstat/libprocstat.h b/lib/libprocstat/libprocstat.h
index f1ca109afcbb..c00a179dae54 100644
--- a/lib/libprocstat/libprocstat.h
+++ b/lib/libprocstat/libprocstat.h
@@ -123,6 +123,10 @@ struct pipestat {
 	uint64_t	addr;
 	uint64_t	peer;
 };
+struct shmstat {
+	uint64_t	size;
+	uint16_t	mode;
+};
 struct sockstat {
 	uint64_t	inp_ppcb;
 	uint64_t	so_addr;
@@ -152,6 +156,8 @@ int	procstat_get_pipe_info(struct procstat *procstat, struct filestat *fst,
     struct pipestat *pipe, char *errbuf);
 int	procstat_get_pts_info(struct procstat *procstat, struct filestat *fst,
     struct ptsstat *pts, char *errbuf);
+int	procstat_get_shm_info(struct procstat *procstat, struct filestat *fst,
+    struct shmstat *shm, char *errbuf);
 int	procstat_get_socket_info(struct procstat *procstat, struct filestat *fst,
     struct sockstat *sock, char *errbuf);
 int	procstat_get_vnode_info(struct procstat *procstat, struct filestat *fst,