storage: Revise API

Pass "struct rmtfd" instead of file descriptors in the interface. This
cleans up the api a little bit, but more importantly allow us to
associate additional things with the remote file descriptors.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rmtfs.c

@@ -51,6 +51,7 @@ static void rmtfs_open(int sock, const struct qrtr_packet *pkt)
 	struct rmtfs_open_resp resp = {};
 	struct rmtfs_open_req req = {};
 	DEFINE_QRTR_PACKET(resp_buf, 256);
+	struct rmtfd *rmtfd;
 	unsigned int txn;
 	ssize_t len;
 	int caller_id = -1;
@@ -63,12 +64,13 @@ static void rmtfs_open(int sock, const struct qrtr_packet *pkt)
 		goto respond;
 	}
 
-	caller_id = storage_get(pkt->node, req.path);
-	if (caller_id < 0) {
+	rmtfd = storage_open(pkt->node, req.path);
+	if (!rmtfd) {
 		qmi_result_error(&resp.result, QMI_RMTFS_ERR_INTERNAL);
 		goto respond;
 	}
 
+	caller_id = storage_get_caller_id(rmtfd);
 	resp.caller_id = caller_id;
 	resp.caller_id_valid = true;
 
@@ -97,6 +99,7 @@ static void rmtfs_close(int sock, const struct qrtr_packet *pkt)
 	struct rmtfs_close_resp resp = {};
 	struct rmtfs_close_req req = {};
 	DEFINE_QRTR_PACKET(resp_buf, 256);
+	struct rmtfd *rmtfd;
 	unsigned int txn;
 	ssize_t len;
 	int ret;
@@ -108,11 +111,13 @@ static void rmtfs_close(int sock, const struct qrtr_packet *pkt)
 		goto respond;
 	}
 
-	ret = storage_put(pkt->node, req.caller_id);
-	if (ret < 0) {
+	rmtfd = storage_get(pkt->node, req.caller_id);
+	if (!rmtfd) {
 		qmi_result_error(&resp.result, QMI_RMTFS_ERR_INTERNAL);
+		goto respond;
 	}
 
+	storage_close(rmtfd);
 	rmtfs_mem_free(rmem);
 
 respond:
@@ -141,6 +146,7 @@ static void rmtfs_iovec(int sock, struct qrtr_packet *pkt)
 	struct rmtfs_iovec_resp resp = {};
 	struct rmtfs_iovec_req req = {};
 	DEFINE_QRTR_PACKET(resp_buf, 256);
+	struct rmtfd *rmtfd;
 	uint32_t caller_id = 0;
 	size_t num_entries = 0;
 	off_t sector_base;
@@ -153,7 +159,6 @@ static void rmtfs_iovec(int sock, struct qrtr_packet *pkt)
 	ssize_t n;
 	char buf[SECTOR_SIZE];
 	int ret;
-	int fd;
 	int i;
 	int j;
 
@@ -170,8 +175,8 @@ static void rmtfs_iovec(int sock, struct qrtr_packet *pkt)
 	num_entries = req.iovec_len;
 	force = req.is_force_sync;
 
-	fd = storage_get_handle(pkt->node, caller_id);
-	if (fd < 0) {
+	rmtfd = storage_get(pkt->node, caller_id);
+	if (!rmtfd) {
 		fprintf(stderr, "[RMTFS] iovec request for non-existing caller\n");
 		qmi_result_error(&resp.result, QMI_RMTFS_ERR_INTERNAL);
 		goto respond;
@@ -186,9 +191,9 @@ static void rmtfs_iovec(int sock, struct qrtr_packet *pkt)
 			if (is_write) {
 				n = rmtfs_mem_read(rmem, phys_base + offset, buf, SECTOR_SIZE);
 				if (n == SECTOR_SIZE)
-					n = storage_pwrite(fd, buf, n, sector_base + offset);
+					n = storage_pwrite(rmtfd, buf, n, sector_base + offset);
 			} else {
-				n = storage_pread(fd, buf, SECTOR_SIZE, sector_base + offset);
+				n = storage_pread(rmtfd, buf, SECTOR_SIZE, sector_base + offset);
 				if (n >= 0) {
 					if (n < SECTOR_SIZE)
 						memset(buf + n, 0, SECTOR_SIZE - n);
@@ -287,7 +292,7 @@ static void rmtfs_get_dev_error(int sock, struct qrtr_packet *pkt)
 	struct rmtfs_dev_error_resp resp = {};
 	struct rmtfs_dev_error_req req = {};
 	DEFINE_QRTR_PACKET(resp_buf, 256);
-	int dev_error = 0;
+	struct rmtfd *rmtfd;
 	unsigned txn;
 	ssize_t len;
 	int ret;
@@ -300,17 +305,17 @@ static void rmtfs_get_dev_error(int sock, struct qrtr_packet *pkt)
 		goto respond;
 	}
 
-	dev_error = storage_get_error(pkt->node, req.caller_id);
-	if (dev_error < 0) {
+	rmtfd = storage_get(pkt->node, req.caller_id);
+	if (rmtfd) {
 		qmi_result_error(&resp.result, QMI_RMTFS_ERR_INTERNAL);
 		goto respond;
 	}
 
-	resp.status = dev_error;
+	resp.status = storage_get_error(rmtfd);
 	resp.status_valid = true;
 
 respond:
-	dbgprintf("[RMTFS] dev_error %d => %d (%d:%d)\n", req.caller_id, dev_error, resp.result.result, resp.result.error);
+	dbgprintf("[RMTFS] dev_error %d => %d (%d:%d)\n", req.caller_id, resp.status, resp.result.result, resp.result.error);
 
 	len = qmi_encode_message(&resp_buf,
 				 QMI_RESPONSE, QMI_RMTFS_GET_DEV_ERROR, txn,
@@ -470,7 +475,7 @@ int main(int argc, char **argv)
 	if (!rmem)
 		return 1;
 
-	ret = storage_open(storage_root);
+	ret = storage_init(storage_root);
 	if (ret) {
 		fprintf(stderr, "failed to initialize storage system\n");
 		goto close_rmtfs_mem;
@@ -487,7 +492,7 @@ int main(int argc, char **argv)
 		ret = run_rmtfs();
 	} while (ret == -ENETRESET);
 
-	storage_close();
+	storage_exit();
 close_rmtfs_mem:
 	rmtfs_mem_close(rmem);
 

rmtfs.h

@@ -23,13 +23,16 @@ void rmtfs_mem_free(struct rmtfs_mem *rmem);
 ssize_t rmtfs_mem_read(struct rmtfs_mem *rmem, unsigned long phys_address, void *buf, ssize_t len);
 ssize_t rmtfs_mem_write(struct rmtfs_mem *rmem, unsigned long phys_address, const void *buf, ssize_t len);
 
-int storage_open(const char *storage_root);
-int storage_get(unsigned node, const char *path);
-int storage_put(unsigned node, int caller_id);
-int storage_get_handle(unsigned node, int caller_id);
-int storage_get_error(unsigned node, int caller_id);
-void storage_close(void);
-ssize_t storage_pread(int fildes, void *buf, size_t nbyte, off_t offset);
-ssize_t storage_pwrite(int fildes, const void *buf, size_t nbyte, off_t offset);
+struct rmtfd;
+
+int storage_init(const char *storage_root);
+struct rmtfd *storage_open(unsigned node, const char *path);
+struct rmtfd *storage_get(unsigned node, int caller_id);
+void storage_close(struct rmtfd *rmtfd);
+int storage_get_caller_id(const struct rmtfd *rmtfd);
+int storage_get_error(const struct rmtfd *rmtfd);
+void storage_exit(void);
+ssize_t storage_pread(const struct rmtfd *rmtfd, void *buf, size_t nbyte, off_t offset);
+ssize_t storage_pwrite(const struct rmtfd *rmtfd, const void *buf, size_t nbyte, off_t offset);
 
 #endif

storage.c

@@ -34,7 +34,7 @@ static const struct partition partition_table[] = {
 
 static struct rmtfd rmtfds[MAX_CALLERS];
 
-int storage_open(const char *storage_root)
+int storage_init(const char *storage_root)
 {
 	int i;
 
@@ -49,7 +49,7 @@ int storage_open(const char *storage_root)
 	return 0;
 }
 
-int storage_get(unsigned node, const char *path)
+struct rmtfd *storage_open(unsigned node, const char *path)
 {
 	char *fspath;
 	const struct partition *part;
@@ -65,7 +65,7 @@ int storage_get(unsigned node, const char *path)
 	}
 
 	fprintf(stderr, "[RMTFS storage] request for unknown partition '%s', rejecting\n", path);
-	return -EPERM;
+	return NULL;
 
 found:
 	/* Check if this node already has the requested path open */
@@ -73,7 +73,7 @@ found:
 		if (rmtfds[i].fd != -1 &&
 		    rmtfds[i].node == node &&
 		    rmtfds[i].partition == part)
-			return rmtfds[i].id;
+			return &rmtfds[i];
 	}
 
 	for (i = 0; i < MAX_CALLERS; i++) {
@@ -84,7 +84,7 @@ found:
 	}
 	if (!rmtfd) {
 		fprintf(stderr, "[storage] out of free rmtfd handles\n");
-		return -EBUSY;
+		return NULL;
 	}
 
 	pathlen = strlen(storage_dir) + strlen(part->actual) + 2;
@@ -95,63 +95,49 @@ found:
 		saved_errno = errno;
 		fprintf(stderr, "[storage] failed to open '%s' (requested '%s'): %s\n",
 				fspath, part->path, strerror(saved_errno));
-		return -saved_errno;
+		errno = saved_errno;
+		return NULL;
 	}
 
 	rmtfd->node = node;
 	rmtfd->fd = fd;
 	rmtfd->partition = part;
 
-	return rmtfd->id;
+	return rmtfd;
 }
 
-int storage_put(unsigned node, int caller_id)
+void storage_close(struct rmtfd *rmtfd)
 {
-	struct rmtfd *rmtfd;
-
-	if (caller_id >= MAX_CALLERS)
-		return -EINVAL;
-
-	rmtfd = &rmtfds[caller_id];
-	if (rmtfd->node != node)
-		return -EINVAL;
-
 	close(rmtfd->fd);
 	rmtfd->fd = -1;
 	rmtfd->partition = NULL;
-
-	return 0;
 }
 
-int storage_get_handle(unsigned node, int caller_id)
+struct rmtfd *storage_get(unsigned node, int caller_id)
 {
 	struct rmtfd *rmtfd;
 
 	if (caller_id >= MAX_CALLERS)
-		return -EINVAL;
+		return NULL;
 
 	rmtfd = &rmtfds[caller_id];
 	if (rmtfd->node != node)
-		return -EINVAL;
+		return NULL;
 
-	return rmtfd->fd;
+	return rmtfd;
 }
 
-int storage_get_error(unsigned node, int caller_id)
+int storage_get_caller_id(const struct rmtfd *rmtfd)
 {
-	struct rmtfd *rmtfd;
-
-	if (caller_id >= MAX_CALLERS)
-		return -EINVAL;
-
-	rmtfd = &rmtfds[caller_id];
-	if (rmtfd->node != node)
-		return -EINVAL;
+	return rmtfd->id;
+}
 
+int storage_get_error(const struct rmtfd *rmtfd)
+{
 	return rmtfd->dev_error;
 }
 
-void storage_close(void)
+void storage_exit(void)
 {
 	int i;
 
@@ -161,13 +147,13 @@ void storage_close(void)
 	}
 }
 
-ssize_t storage_pread(int fildes, void *buf, size_t nbyte, off_t offset)
+ssize_t storage_pread(const struct rmtfd *rmtfd, void *buf, size_t nbyte, off_t offset)
 {
-	return pread(fildes, buf, nbyte, offset);
+	return pread(rmtfd->fd, buf, nbyte, offset);
 }
 
-ssize_t storage_pwrite(int fildes, const void *buf, size_t nbyte, off_t offset)
+ssize_t storage_pwrite(const struct rmtfd *rmtfd, const void *buf, size_t nbyte, off_t offset)
 {
-	return pwrite(fildes, buf, nbyte, offset);
+	return pwrite(rmtfd->fd, buf, nbyte, offset);
 }