5 files changed, 125 insertions, 3 deletions

diff --git a/discover/device-handler.c b/discover/device-handler.c
index fc280af..04a4484 100644
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -721,12 +721,15 @@ static bool check_existing_mount(struct discover_device *dev)
 			continue;
 
 		if (mntstat.st_rdev == devstat.st_rdev) {
-			pb_debug("%s: %s is already mounted at %s\n"
-					__func__, dev->device_path,
-					mnt->mnt_dir);
 			dev->mount_path = talloc_strdup(dev, mnt->mnt_dir);
+			dev->mounted_rw = !!hasmntopt(mnt, "rw");
 			dev->mounted = true;
 			dev->unmount = false;
+
+			pb_debug("%s: %s is already mounted (r%c) at %s\n",
+					__func__, dev->device_path,
+					dev->mounted_rw ? 'w' : 'o',
+					mnt->mnt_dir);
 			break;
 		}
 	}
@@ -763,6 +766,7 @@ static int mount_device(struct discover_device *dev)
 			"-o", "ro", NULL);
 	if (!rc) {
 		dev->mounted = true;
+		dev->mounted_rw = false;
 		dev->unmount = true;
 		return 0;
 	}
@@ -773,6 +777,7 @@ static int mount_device(struct discover_device *dev)
 
 	if (!rc) {
 		dev->mounted = true;
+		dev->mounted_rw = true;
 		dev->unmount = true;
 		return 0;
 	}
@@ -805,6 +810,39 @@ static int umount_device(struct discover_device *dev)
 
 	return 0;
 }
+
+int device_request_write(struct discover_device *dev, bool *release)
+{
+	int rc;
+
+	*release = false;
+
+	if (!dev->mounted)
+		return -1;
+
+	if (dev->mounted_rw)
+		return 0;
+
+	rc = process_run_simple(dev, pb_system_apps.mount, dev->mount_path,
+			"-o", "remount,rw", NULL);
+	if (rc)
+		return -1;
+
+	dev->mounted_rw = true;
+	*release = true;
+	return 0;
+}
+
+void device_release_write(struct discover_device *dev, bool release)
+{
+	if (!release)
+		return;
+
+	process_run_simple(dev, pb_system_apps.mount, dev->mount_path,
+			"-o", "remount,ro", NULL);
+	dev->mounted_rw = false;
+}
+
 #else
 
 static int umount_device(struct discover_device *dev __attribute__((unused)))
@@ -818,5 +856,17 @@ static int __attribute__((unused)) mount_device(
 	return 0;
 }
 
+int device_request_write(struct discover_device *dev __attribute__((unused)),
+		bool *release)
+{
+	*release = true;
+	return 0;
+}
+
+void device_release_write(struct discover_device *dev __attribute__((unused)),
+	bool release __attribute__((unused)))
+{
+}
+
 #endif
 
diff --git a/discover/device-handler.h b/discover/device-handler.h
index 5dbc349..6b36e07 100644
--- a/discover/device-handler.h
+++ b/discover/device-handler.h
@@ -36,6 +36,7 @@ struct discover_device {
 	char			*mount_path;
 	const char		*device_path;
 	bool			mounted;
+	bool			mounted_rw;
 	bool			unmount;
 
 	bool			notified;
@@ -124,4 +125,7 @@ void device_handler_boot(struct device_handler *handler,
 		struct boot_command *cmd);
 void device_handler_cancel_default(struct device_handler *handler);
 
+int device_request_write(struct discover_device *dev, bool *release);
+void device_release_write(struct discover_device *dev, bool release);
+
 #endif /* _DEVICE_HANDLER_H */
diff --git a/discover/parser.c b/discover/parser.c
index d34600d..4816916 100644
--- a/discover/parser.c
+++ b/discover/parser.c
@@ -49,6 +49,35 @@ int parser_request_file(struct discover_context *ctx,
 	return rc;
 }
 
+int parser_replace_file(struct discover_context *ctx,
+		struct discover_device *dev, const char *filename,
+		char *buf, int len)
+{
+	bool release;
+	char *path;
+	int rc;
+
+	if (!dev->mounted)
+		return -1;
+
+	rc = device_request_write(dev, &release);
+	if (rc) {
+		pb_log("Can't write file %s: device doesn't allow write\n",
+				dev->device_path);
+		return -1;
+	}
+
+	path = local_path(ctx, dev, filename);
+
+	rc = replace_file(path, buf, len);
+
+	talloc_free(path);
+
+	device_release_write(dev, release);
+
+	return rc;
+}
+
 static int download_config(struct discover_context *ctx, char **buf, int *len)
 {
 	struct load_url_result *result;
diff --git a/discover/parser.h b/discover/parser.h
index c1b4012..2aaa077 100644
--- a/discover/parser.h
+++ b/discover/parser.h
@@ -51,8 +51,17 @@ void parser_init(void);
 void iterate_parsers(struct discover_context *ctx, enum conf_method method);
 int parse_user_event(struct discover_context *ctx, struct event *event);
 
+/* File IO functions for parsers; these should be the only interface that
+ * parsers use to access a device's filesystem.
+ *
+ * These are intended for small amounts of data, typically text configuration
+ * and state files.
+ */
 int parser_request_file(struct discover_context *ctx,
 		struct discover_device *dev, const char *filename,
 		char **buf, int *len);
+int parser_replace_file(struct discover_context *ctx,
+		struct discover_device *dev, const char *filename,
+		char *buf, int len);
 
 #endif /* _PARSER_H */
diff --git a/test/parser/utils.c b/test/parser/utils.c
index d1ced73..33efda8 100644
--- a/test/parser/utils.c
+++ b/test/parser/utils.c
@@ -186,6 +186,36 @@ int parser_request_file(struct discover_context *ctx,
 	return -1;
 }
 
+int parser_replace_file(struct discover_context *ctx,
+		struct discover_device *dev, const char *filename,
+		char *buf, int len)
+{
+	struct parser_test *test = ctx->test_data;
+	struct test_file *f, *file;
+
+	list_for_each_entry(&test->files, f, list) {
+		if (f->dev != dev)
+			continue;
+		if (strcmp(f->name, filename))
+			continue;
+
+		file = f;
+		break;
+	}
+
+	if (!file) {
+		file = talloc_zero(test, struct test_file);
+		file->dev = dev;
+		file->name = filename;
+		list_add(&test->files, &file->list);
+	} else {
+		talloc_free(file->data);
+	}
+
+	file->data = talloc_memdup(test, buf, len);
+	file->size = len;
+	return 0;
+}
 int test_run_parser(struct parser_test *test, const char *parser_name)
 {
 	struct p_item* i;