From a20c0b71dc29e1e2d5637366426e7b9ae058f15b Mon Sep 17 00:00:00 2001 From: Christophe Lyon Date: Wed, 4 Jul 2018 17:55:35 +0200 Subject: nptl: Allow sem_open to work on MMU-less systems MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Allow both tmpfs and ramfs for shm devices. * libpthread/nptl/linux_fsinfo.h (SHMFS_SUPER_MAGIC_WITH_MMU): Define. (SHMFS_SUPER_MAGIC_WITHOUT_MMU): Define. * libpthread/nptl/sem_open.c (__where_is_shmfs): Add support for SHMFS_SUPER_MAGIC_WITHOUT_MMU. Signed-off-by: Mickaël Guêné Signed-off-by: Christophe Lyon --- libpthread/nptl/linux_fsinfo.h | 5 ++++- libpthread/nptl/sem_open.c | 8 ++++++-- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/libpthread/nptl/linux_fsinfo.h b/libpthread/nptl/linux_fsinfo.h index 8537581a2..4abe7920d 100644 --- a/libpthread/nptl/linux_fsinfo.h +++ b/libpthread/nptl/linux_fsinfo.h @@ -126,7 +126,10 @@ #define XENIX_SUPER_MAGIC 0x012ff7b4 /* Constant that identifies the `shm' filesystem. */ -#define SHMFS_SUPER_MAGIC 0x01021994 +/* Mount as tmpfs. */ +#define SHMFS_SUPER_MAGIC_WITH_MMU 0x01021994 +/* The kernel uses a ramfs file system for tmpfs. */ +#define SHMFS_SUPER_MAGIC_WITHOUT_MMU 0x858458f6 /* Constants that identify the `xfs' filesystem. */ #define XFS_SUPER_MAGIC 0x58465342 diff --git a/libpthread/nptl/sem_open.c b/libpthread/nptl/sem_open.c index d811ec503..2746da1b7 100644 --- a/libpthread/nptl/sem_open.c +++ b/libpthread/nptl/sem_open.c @@ -72,7 +72,9 @@ __where_is_shmfs (void) /* The canonical place is /dev/shm. This is at least what the documentation tells everybody to do. */ - if (__statfs (defaultmount, &f) == 0 && f.f_type == SHMFS_SUPER_MAGIC) + if (__statfs (defaultmount, &f) == 0 + && (f.f_type == SHMFS_SUPER_MAGIC_WITH_MMU + || f.f_type == SHMFS_SUPER_MAGIC_WITHOUT_MMU)) { /* It is in the normal place. */ mountpoint.dir = (char *) defaultdir; @@ -106,7 +108,9 @@ __where_is_shmfs (void) /* First make sure this really is the correct entry. At least some versions of the kernel give wrong information because of the implicit mount of the shmfs for SysV IPC. */ - if (__statfs (mp->mnt_dir, &f) != 0 || f.f_type != SHMFS_SUPER_MAGIC) + if (__statfs (mp->mnt_dir, &f) != 0 + || (f.f_type != SHMFS_SUPER_MAGIC_WITH_MMU + && f.f_type != SHMFS_SUPER_MAGIC_WITHOUT_MMU)) continue; namelen = strlen (mp->mnt_dir); -- cgit v1.2.3