posix: implement POSIX semaphore interfaces

include/semaphore.h

@@ -0,0 +1,61 @@
+/*
+ * Phoenix-RTOS
+ *
+ * libphoenix
+ *
+ * POSIX implementation - semaphores
+ *
+ * Copyright 2026 Phoenix Systems
+ * Author: Michał Lach
+ *
+ * This file is part of Phoenix-RTOS.
+ *
+ * %LICENSE%
+ */
+
+#include <time.h>
+#include <limits.h>
+#include <sys/threads.h>
+#include <sys/semaphore.h>
+
+#define SEM_FAILED ((sem_t *)0xDAAB0000)
+
+typedef struct {
+	/* clang-format off */
+	enum { smNamed, smUnnamed } type;
+	/* clang-format on */
+
+	union {
+		semaphore_t unnamed;
+		oid_t named;
+	};
+} sem_t;
+
+extern int sem_wait(sem_t *sem);
+
+
+extern int sem_trywait(sem_t *sem);
+
+
+extern int sem_timedwait(sem_t *restrict sem, const struct timespec *restrict abs_timeout);
+
+
+extern int sem_getvalue(sem_t *restrict sem, int *restrict value);
+
+
+extern int sem_post(sem_t *sem);
+
+
+extern int sem_close(sem_t *sem);
+
+
+extern sem_t *sem_open(const char *name, int oflag, ... /* mode_t mode, unsigned int value */);
+
+
+extern int sem_unlink(const char *name);
+
+
+extern int sem_destroy(sem_t *sem);
+
+
+extern int sem_init(sem_t *sem, int pshared, unsigned int value);

include/sys/semaphore.h

@@ -0,0 +1,28 @@
+/*
+ * Phoenix-RTOS
+ *
+ * libphoenix
+ *
+ * POSIX implementation - semaphores
+ *
+ * Copyright 2026 Phoenix Systems
+ * Author: Michał Lach
+ *
+ * This file is part of Phoenix-RTOS.
+ *
+ * %LICENSE%
+ */
+
+#include <limits.h>
+#include <sys/ioctl.h>
+
+#define SEMAPHORE_PATH      "/dev/posix/sem/"
+#define SEMCTL_PATH         "/dev/posix/semctl"
+#define SEMAPHORE_MAX_COUNT (128)
+#define SEMAPHORE_NAME_MAX  (NAME_MAX - sizeof(SEMAPHORE_PATH) - 1)
+#define SEM_VALUE_MAX       INT_MAX
+
+#define SEM_UP           _IO('s', 0x1)
+#define SEM_DOWN         _IO('s', 0x2)
+#define SEM_DOWN_TRY     _IO('s', 0x3)
+#define SEM_DOWN_TIMEOUT _IOW('s', 0x4, time_t)

include/sys/threads.h

@@ -113,12 +113,18 @@ extern int semaphoreCreate(semaphore_t *s, unsigned int v);
 extern int semaphoreDown(semaphore_t *s, time_t timeout);
 
 
+extern int semaphoreTryDown(semaphore_t *s);
+
+
 extern int semaphoreUp(semaphore_t *s);
 
 
 extern int semaphoreDone(semaphore_t *s);
 
 
+extern int semaphoreCount(semaphore_t *s);
+
+
 extern int phCondCreate(handle_t *h, const struct condAttr *attr);
 
 

posix/Makefile

@@ -5,4 +5,4 @@
 # Author: Pawel Pisarczyk
 #
 
-OBJS += $(addprefix $(PREFIX_O)posix/, stubs.o utils.o idtree.o)
+OBJS += $(addprefix $(PREFIX_O)posix/, stubs.o utils.o idtree.o sem.o)