From 27cebb780be4142afe6356cbbc57775a33e8e55e Mon Sep 17 00:00:00 2001 From: Matthew Heon Date: Fri, 27 Apr 2018 16:06:02 -0400 Subject: Initial skeleton of in-memory locks Signed-off-by: Matthew Heon --- libpod/lock/shm_lock.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 libpod/lock/shm_lock.h (limited to 'libpod/lock/shm_lock.h') diff --git a/libpod/lock/shm_lock.h b/libpod/lock/shm_lock.h new file mode 100644 index 000000000..6988789dd --- /dev/null +++ b/libpod/lock/shm_lock.h @@ -0,0 +1,43 @@ +#ifndef shm_locks_h_ +#define shm_locks_h_ + +#include +#include + +// Magic number to ensure we open the right SHM segment +#define MAGIC 0xA5A5 + +// Name of the SHM +#define SHM_NAME "/libpod_lock" + +// Type for our bitmaps +typedef uint32_t bitmap_t; + +// bitmap size +#define BITMAP_SIZE (sizeof(bitmap_t) * 8) + +// Struct to hold a single bitmap and associated locks +typedef struct lock_group { + bitmap_t bitmap; + sem_t locks[BITMAP_SIZE]; +} lock_group_t; + +// Struct to hold our SHM locks +typedef struct shm_struct { + uint16_t magic; + sem_t segment_lock; + uint32_t num_bitmaps; + uint32_t num_locks; + lock_group_t locks[]; +} shm_struct_t; + +size_t compute_shm_size(uint32_t num_bitmaps); +shm_struct_t *setup_lock_shm(uint32_t num_locks); +shm_struct_t *open_lock_shm(uint32_t num_locks); +int32_t close_lock_shm(shm_struct_t *shm); +int64_t allocate_semaphore(shm_struct_t *shm); +int32_t deallocate_semaphore(shm_struct_t *shm, uint32_t sem_index); +int32_t lock_semaphore(shm_struct_t *shm, uint32_t sem_index); +int32_t unlock_semaphore(shm_struct_t *shm, uint32_t sem_index); + +#endif -- cgit v1.2.3-54-g00ecf