[newlib 09/65] Add an shm_rename syscall

Sebastian Huber sebastian.huber at embedded-brains.de
Thu Jul 7 11:58:16 UTC 2022

From: David Bright <dab at FreeBSD.org>

Add an atomic shm rename operation, similar in spirit to a file
rename. Atomically unlink an shm from a source path and link it to a
destination path. If an existing shm is linked at the destination
path, unlink it as part of the same atomic operation. The caller needs
the same permissions as shm_unlink to the shm being renamed, and the
same permissions for the shm at the destination which is being
unlinked, if it exists. If those fail, EACCES is returned, as with the
other shm_* syscalls.

truss support is included; audit support will come later.

This commit includes only the implementation; the sysent-generated
bits will come in a follow-on commit.

Submitted by:	Matthew Bryan <matthew.bryan at isilon.com>
Reviewed by:	jilles (earlier revision)
Reviewed by:	brueffer (manpages, earlier revision)
Relnotes:	yes
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D21423
 newlib/libc/sys/rtems/include/sys/mman.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/newlib/libc/sys/rtems/include/sys/mman.h b/newlib/libc/sys/rtems/include/sys/mman.h
index 867b68647..89cc4d699 100644
--- a/newlib/libc/sys/rtems/include/sys/mman.h
+++ b/newlib/libc/sys/rtems/include/sys/mman.h
@@ -133,6 +133,14 @@
 #define MAP_FAILED	((void *)-1)
+ * Flags provided to shm_rename
+ */
+/* Don't overwrite dest, if it exists */
+#define SHM_RENAME_NOREPLACE	(1 << 0)
+/* Atomically swap src and dest */
+#define SHM_RENAME_EXCHANGE	(1 << 1)
  * msync() flags
@@ -264,6 +272,7 @@ int	posix_madvise(void *, size_t, int);
 int	mlockall(int);
 int	munlockall(void);
 int	shm_open(const char *, int, mode_t);
+int	shm_rename(const char *, const char *, int);
 int	shm_unlink(const char *);

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