[feature] support offsets for file mappings

Replace the unused "max" argument for file-based mappings with an offset
argument (until now the offset was hardcoded to 0).

src/aml.h

@@ -224,7 +224,7 @@ void *aml_area_linux_mmap_generic(struct aml_area_linux_mmap_data *data,
 				  void *ptr, size_t size);
 int aml_area_linux_mmap_anonymous_init(struct aml_area_linux_mmap_data *data);
 int aml_area_linux_mmap_fd_init(struct aml_area_linux_mmap_data *data, int fd,
-				size_t max);
+				off_t offset);
 int aml_area_linux_mmap_tmpfile_init(struct aml_area_linux_mmap_data *data,
 				     char *template, size_t max);
 int aml_area_linux_mmap_anonymous_destroy(struct aml_area_linux_mmap_data *data);

src/area_linux.c

@@ -176,8 +176,8 @@ int aml_area_linux_vinit(struct aml_area *a, int manager_type,
 	else if(mmap_type == AML_AREA_LINUX_MMAP_TYPE_FD)
 	{
 		int fd = va_arg(ap, int);
-		size_t max = va_arg(ap, size_t);
-		aml_area_linux_mmap_fd_init(&area->data.mmap, fd, max);
+		off_t offset = va_arg(ap, off_t);
+		aml_area_linux_mmap_fd_init(&area->data.mmap, fd, offset);
 	}
 	else if(mmap_type == AML_AREA_LINUX_MMAP_TYPE_TMPFILE)
 	{

src/area_linux_mmap.c

@@ -36,14 +36,14 @@ int aml_area_linux_mmap_anonymous_destroy(struct aml_area_linux_mmap_data *data)
 }
 
 int aml_area_linux_mmap_fd_init(struct aml_area_linux_mmap_data *data, int fd,
-				size_t max)
+				off_t offset)
 {
 	/* TODO: should we check for the right open flags ? */
 	assert(data != NULL);
 	data->prot = PROT_READ|PROT_WRITE;
 	data->flags = MAP_PRIVATE;
 	data->fildes = fd;
-	data->off = 0;
+	data->off = offset;
 	return 0;
 }
 

tests/linux_mmap.c

@@ -50,7 +50,7 @@ int main(int argc, char *argv[])
 	assert(tmpfile != -1);
 	/* use ftruncate to make sure we have enough space in the file. */
 	ftruncate(tmpfile, ALLOC_SIZE);
-	aml_area_linux_mmap_fd_init(&config[1], tmpfile, ALLOC_SIZE);
+	aml_area_linux_mmap_fd_init(&config[1], tmpfile, 0);
 
 	aml_area_linux_mmap_tmpfile_init(&config[2], tmpname2, ALLOC_SIZE);