support for writable mmap

src/tus_file.c

@@ -418,8 +418,10 @@ tus_mmap_header(int fd)
 	    MAP_SHARED | MAP_NORESERVE, fd, 0));
 }
 
+static char * empty = "";
+
 void
-tus_file_mmap(struct tus_file_core *fcore)
+tus_file_complete(struct tus_file_core *fcore)
 {
 	struct tus_file_disk *fdisk;
 
@@ -427,15 +429,56 @@ tus_file_mmap(struct tus_file_core *fcore)
 	fdisk = fcore->disk;
 	CHECK_TUS_FILE_DISK(fdisk);
 
-	assert(fdisk->upload_length == fdisk->upload_offset);
+	assert(fdisk->upload_offset == fdisk->upload_length);
+
+	if (fdisk->upload_offset > 0) {
+		tus_file_mmap(fcore);
+		return;
+	}
+
+	AZ(fdisk->upload_length);
+	AZ(fdisk->upload_offset);
+	AZ(fcore->ptr);
+	AZ(fcore->len);
 	assert(fcore->ptr_type == TFCP_INVALID);
+	fcore->ptr_type = TFCP_EMPTY;
+	fcore->ptr = empty;
+}
+
+void
+tus_file_mmap(struct tus_file_core *fcore)
+{
+	struct tus_file_disk *fdisk;
+	int prot = PROT_READ;
+
+	CHECK_OBJ_NOTNULL(fcore, VMOD_TUS_FILE_CORE_MAGIC);
+	fdisk = fcore->disk;
+	CHECK_TUS_FILE_DISK(fdisk);
+
+	if (fcore->ptr != NULL) {
+		assert(fcore->ptr_type >= TFCP_MMAP_RO);
+		return;
+	}
+
 	AZ(fcore->ptr);
 	AZ(fcore->len);
+	assert(fcore->ptr_type == TFCP_INVALID);
 
-	fcore->ptr = mmap(NULL, fdisk->upload_length, PROT_READ,
+	assert(fdisk->upload_offset > 0);
+	assert(fdisk->upload_length > 0);
+	assert(fdisk->upload_offset <= fdisk->upload_length);
+	if (fdisk->upload_offset < fdisk->upload_length) {
+		prot |= PROT_WRITE;
+		// XXX error handling
+		AZ(fallocate(fcore->fd, 0, 0,
+		    header_size + fdisk->upload_length));
+	}
+
+	fcore->ptr = mmap(NULL, fdisk->upload_length, prot,
 	    MAP_SHARED | MAP_NORESERVE, fcore->fd, header_size);
 	AN(fcore->ptr);
-	fcore->ptr_type = TFCP_MMAP_RO;
+	fcore->ptr_type = (prot & PROT_WRITE) ?
+		TFCP_MMAP_RW : TFCP_MMAP_RO;
 	tus_file_close(fcore);
 	fcore->len = fdisk->upload_length;
 }
@@ -476,12 +519,19 @@ tus_file_fini(struct tus_file_core *fcore)
 
 	if (fdisk->type == TUS_FINAL) {
 		tus_file_final_fini(fcore);
-	} else if (fcore->ptr != NULL) {
+	} else if (fcore->ptr != NULL && fcore->ptr_type >= TFCP_MMAP_RO) {
 		fcore->ptr_type = TFCP_INVALID;
 		(void) munmap(fcore->ptr, fcore->len);
 		fcore->ptr = NULL;
 		fcore->len = 0;
+	} else if (fcore->ptr != NULL && fcore->ptr_type == TFCP_EMPTY) {
+		fcore->ptr_type = TFCP_INVALID;
+		fcore->ptr = NULL;
+		fcore->len = 0;
 	}
+	assert(fcore->ptr_type == TFCP_INVALID);
+	AZ(fcore->ptr);
+	AZ(fcore->len);
 
 	fcore->disk = NULL;
 	tus_file_disk_del(&fdisk, &fcore->fd, fcore->filename,

src/tus_file.h

@@ -172,6 +172,7 @@ struct tus_file_core *tus_file_new(VRT_CTX, struct VPFX(tus_server) *,
     unsigned *, const char **);
 struct tus_file_core *tus_file_lookup(struct VPFX(tus_server) *, const char *);
 unsigned tus_body_to_file(VRT_CTX, struct tus_file_core *);
+void tus_file_complete(struct tus_file_core *);
 void tus_file_mmap(struct tus_file_core *);
 
 #ifdef BAD_IDEA

src/tus_request.c

@@ -504,7 +504,7 @@ tus_request(VRT_CTX, struct VPFX(tus_server) *tussrv,
 		return (0);
 	}
 	if (fdisk->upload_offset == fdisk->upload_length) {
-		tus_file_mmap(r->fcore);
+		tus_file_complete(r->fcore);
 		AZ(pthread_cond_signal(&r->fcore->cond));
 		if (type == TUS_PARTIAL)
 			return (0);