Merge pull request llvm#120 from pcc/filc11

Futex syscall: implement timeouts, FUTEX_WAIT_BITSET, FUTEX_CLOCK_REA…

Author: pizlonator

filc/include/pizlonated_syscalls.h

@@ -221,7 +221,7 @@ int zsys_uname(void* buf);
 int zsys_sendfile(int out_fd, int in_fd, long* offset, __SIZE_TYPE__ count);
 void zsys_futex_wake(volatile int* addr, int cnt, int priv);
 void zsys_futex_wait(volatile int* addr, int val, int priv);
-/* These futex calls return the errno as a negative value. They do not set errno.
+/* These futex calls return the errno as a positive value. They do not set errno.
  
    NOTE: the futex_timedwait uses an absolute timeout, which is not what the real futex syscall
    uses! */

filc/src/runtime.c

@@ -30,6 +30,8 @@
 #include <stdfil.h>
 #include <pizlonated_syscalls.h>
 #include <pizlonated_runtime.h>
+#include <linux/futex.h>
+#include <linux/time.h>
 
 unsigned zversion(void)
 {
@@ -465,15 +467,11 @@ struct futex_args {
 	volatile void* uaddr;
 	long futex_op;
 	unsigned long val;
-	const void* timeout;
+	const struct timespec* timeout;
 	volatile void* uaddr2;
 	unsigned long val3;
 };
 
-#define FUTEX_WAIT    0
-#define FUTEX_WAKE    1
-#define FUTEX_PRIVATE 128
-
 long zsys_syscall(long n, ...)
 {
     /* The goal is to have this code support all syscalls, but it doesn't do that, yet. So,
@@ -493,13 +491,38 @@ long zsys_syscall(long n, ...)
         struct futex_args* args = (struct futex_args*)syscall_args;
         switch (args->futex_op) {
         case FUTEX_WAIT:
-        case FUTEX_WAIT | FUTEX_PRIVATE:
-            ZASSERT(!args->timeout);
-            zsys_futex_wait(args->uaddr, args->val, args->futex_op & FUTEX_PRIVATE);
+        case FUTEX_WAIT | FUTEX_PRIVATE_FLAG:
+        case FUTEX_WAIT | FUTEX_CLOCK_REALTIME:
+        case FUTEX_WAIT | FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME:
+        case FUTEX_WAIT_BITSET:
+        case FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG:
+        case FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME:
+        case FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME: {
+            if (args->futex_op & FUTEX_WAIT_BITSET)
+                ZASSERT(args->val3 == FUTEX_BITSET_MATCH_ANY);
+            int clock_id = (args->futex_op & FUTEX_CLOCK_REALTIME) ? CLOCK_REALTIME : CLOCK_MONOTONIC;
+            struct timespec timeout = {};
+            if (args->timeout) {
+                if (!(args->futex_op & FUTEX_WAIT_BITSET))
+                    zsys_clock_gettime(clock_id, &timeout);
+                timeout.tv_sec += args->timeout->tv_sec;
+                timeout.tv_nsec += args->timeout->tv_nsec;
+                if (timeout.tv_nsec >= 1000000000) {
+                    timeout.tv_sec++;
+                    timeout.tv_nsec -= 1000000000;
+                }
+            }
+            int err = zsys_futex_timedwait(args->uaddr, args->val, clock_id,
+                args->timeout ? &timeout : 0, args->futex_op & FUTEX_PRIVATE_FLAG);
+            if (err > 0) {
+                zset_errno(err);
+                return -1;
+            }
             return 0;
+        }
         case FUTEX_WAKE:
-        case FUTEX_WAKE | FUTEX_PRIVATE:
-            zsys_futex_wake(args->uaddr, args->val, args->futex_op & FUTEX_PRIVATE);
+        case FUTEX_WAKE | FUTEX_PRIVATE_FLAG:
+            zsys_futex_wake(args->uaddr, args->val, args->futex_op & FUTEX_PRIVATE_FLAG);
             return 0;
         default:
             zerrorf("unsupported futex op: %d.", args->futex_op);

filc/tests/futextimeout/futextimeout.c

@@ -0,0 +1,42 @@
+#include <errno.h>
+#include <linux/futex.h>
+#include <stdfil.h>
+#include <stdint.h>
+#include <sys/syscall.h>
+#include <time.h>
+#include <unistd.h>
+
+struct timespec now_plus(int clock_id, struct timespec addend)
+{
+    struct timespec result;
+    clock_gettime(clock_id, &result);
+    result.tv_sec += addend.tv_sec;
+    result.tv_nsec += addend.tv_nsec;
+    if (result.tv_nsec >= 1000000000) {
+        result.tv_sec++;
+        result.tv_nsec -= 1000000000;
+    }
+    return result;
+}
+
+int main()
+{
+    struct timespec ten_ms = {0, 10000000};
+    uint32_t fw = 0;
+
+    /* These take a relative timespec. */
+    ZASSERT(syscall(SYS_futex, &fw, FUTEX_WAIT, 0, &ten_ms, 0, 0) == -1);
+    ZASSERT(errno == ETIMEDOUT);
+    ZASSERT(syscall(SYS_futex, &fw, FUTEX_WAIT | FUTEX_CLOCK_REALTIME, 0, &ten_ms, 0, 0) == -1);
+    ZASSERT(errno == ETIMEDOUT);
+
+    /* These take an absolute timespec. */
+    struct timespec timeout = now_plus(CLOCK_MONOTONIC, ten_ms);
+    ZASSERT(syscall(SYS_futex, &fw, FUTEX_WAIT_BITSET, 0, &timeout, 0, FUTEX_BITSET_MATCH_ANY) == -1);
+    ZASSERT(errno == ETIMEDOUT);
+    timeout = now_plus(CLOCK_REALTIME, ten_ms);
+    ZASSERT(syscall(SYS_futex, &fw, FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME, 0, &timeout, 0,
+                FUTEX_BITSET_MATCH_ANY)
+        == -1);
+    ZASSERT(errno == ETIMEDOUT);
+}

filc/tests/futextimeout/manifest

@@ -0,0 +1,2 @@
+return:
+  success