4 files changed, 69 insertions, 0 deletions
diff --git a/pixman/test/Makefile.am b/pixman/test/Makefile.am
index efd9cd91a..d3e9d3fa0 100644
--- a/pixman/test/Makefile.am
+++ b/pixman/test/Makefile.am
@@ -13,6 +13,7 @@ TESTPROGRAMS =			\
 	gradient-crash-test	\
 	trap-crasher		\
 	alphamap		\
+	alpha-loop		\
 	scaling-crash-test	\
 	blitters-test		\
 	scaling-test		\
@@ -39,6 +40,9 @@ scaling_test_SOURCES = scaling-test.c utils.c utils.h
 alphamap_LDADD = $(TEST_LDADD)
 alphamap_SOURCES = alphamap.c utils.c utils.h
 
+alpha_loop_LDADD = $(TEST_LDADD)
+alpha_loop_SOURCES = alpha-loop.c utils.c utils.h
+
 # GTK using test programs
 
 if HAVE_GTK
diff --git a/pixman/test/alpha-loop.c b/pixman/test/alpha-loop.c
new file mode 100644
index 000000000..38fc21f5d
--- /dev/null
+++ b/pixman/test/alpha-loop.c
@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "utils.h"
+
+#define WIDTH 400
+#define HEIGHT 200
+
+int
+main (int argc, char **argv)
+{
+    uint8_t *alpha = make_random_bytes (WIDTH * HEIGHT);
+    uint32_t *src = (uint32_t *)make_random_bytes (WIDTH * HEIGHT * 4);
+    uint32_t *dest = (uint32_t *)make_random_bytes (WIDTH * HEIGHT * 4);
+
+    pixman_image_t *a = pixman_image_create_bits (PIXMAN_a8, WIDTH, HEIGHT, (uint32_t *)alpha, WIDTH);
+    pixman_image_t *d = pixman_image_create_bits (PIXMAN_a8r8g8b8, WIDTH, HEIGHT, dest, WIDTH * 4);
+    pixman_image_t *s = pixman_image_create_bits (PIXMAN_a2r10g10b10, WIDTH, HEIGHT, src, WIDTH * 4);
+
+    fail_after (5, "Infinite loop detected: 5 seconds without progress\n");
+
+    pixman_image_set_alpha_map (s, a, 0, 0);
+    pixman_image_set_alpha_map (a, s, 0, 0);
+
+    pixman_image_composite (PIXMAN_OP_SRC, s, NULL, d, 0, 0, 0, 0, 0, 0, WIDTH, HEIGHT);
+
+    pixman_image_unref (s);
+
+    return 0;
+}
diff --git a/pixman/test/utils.c b/pixman/test/utils.c
index 4b68debff..f5199268b 100644
--- a/pixman/test/utils.c
+++ b/pixman/test/utils.c
@@ -1,4 +1,9 @@
 #include "utils.h"
+#include <signal.h>
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
 
 /* Random number seed
  */
@@ -319,3 +324,31 @@ fuzzer_test_main (const char *test_name,
 
     return 0;
 }
+
+static const char *global_msg;
+
+static void
+on_alarm (int signo)
+{
+    printf ("%s\n", global_msg);
+    exit (1);
+}
+
+void
+fail_after (int seconds, const char *msg)
+{
+#ifdef HAVE_SIGACTION
+#ifdef HAVE_ALARM
+    struct sigaction action;
+
+    global_msg = msg;
+
+    memset (&action, 0, sizeof (action));
+    action.sa_handler = on_alarm;
+
+    alarm (seconds);
+
+    sigaction (SIGALRM, &action, NULL);
+#endif
+#endif
+}
diff --git a/pixman/test/utils.h b/pixman/test/utils.h
index 39b49b2c1..a5b3c91c4 100644
--- a/pixman/test/utils.h
+++ b/pixman/test/utils.h
@@ -62,3 +62,6 @@ fuzzer_test_main (const char *test_name,
 		  uint32_t    (*test_function)(int testnum, int verbose),
 		  int         argc,
 		  const char *argv[]);
+
+void
+fail_after (int seconds, const char *msg);