diff options
Diffstat (limited to 'common/state/backend_bucket_direct.c')
| -rw-r--r-- | common/state/backend_bucket_direct.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/common/state/backend_bucket_direct.c b/common/state/backend_bucket_direct.c new file mode 100644 index 0000000000..08892f001e --- /dev/null +++ b/common/state/backend_bucket_direct.c @@ -0,0 +1,180 @@ +/* + * Copyright (C) 2016 Pengutronix, Markus Pargmann <mpa@pengutronix.de> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <fcntl.h> +#include <fs.h> +#include <libfile.h> +#include <linux/kernel.h> +#include <malloc.h> +#include <printk.h> + +#include "state.h" + +struct state_backend_storage_bucket_direct { + struct state_backend_storage_bucket bucket; + + ssize_t offset; + ssize_t max_size; + + int fd; + + struct device_d *dev; +}; + +struct state_backend_storage_bucket_direct_meta { + uint32_t magic; + uint32_t written_length; +}; +static const uint32_t direct_magic = 0x2354fdf3; + +static inline struct state_backend_storage_bucket_direct + *get_bucket_direct(struct state_backend_storage_bucket *bucket) +{ + return container_of(bucket, struct state_backend_storage_bucket_direct, + bucket); +} + +static int state_backend_bucket_direct_read(struct state_backend_storage_bucket + *bucket, uint8_t ** buf_out, + ssize_t * len_hint) +{ + struct state_backend_storage_bucket_direct *direct = + get_bucket_direct(bucket); + struct state_backend_storage_bucket_direct_meta meta; + ssize_t read_len; + uint8_t *buf; + int ret; + + ret = lseek(direct->fd, direct->offset, SEEK_SET); + if (ret < 0) { + dev_err(direct->dev, "Failed to seek file, %d\n", ret); + return ret; + } + ret = read_full(direct->fd, &meta, sizeof(meta)); + if (ret < 0) { + dev_err(direct->dev, "Failed to read meta data from file, %d\n", ret); + return ret; + } + if (meta.magic == direct_magic) { + read_len = meta.written_length; + } else { + if (*len_hint) + read_len = *len_hint; + else + read_len = direct->max_size; + ret = lseek(direct->fd, direct->offset, SEEK_SET); + if (ret < 0) { + dev_err(direct->dev, "Failed to seek file, %d\n", ret); + return ret; + } + } + if (direct->max_size) + read_len = min(read_len, direct->max_size); + + buf = xmalloc(read_len); + if (!buf) + return -ENOMEM; + + ret = read_full(direct->fd, buf, read_len); + if (ret < 0) { + dev_err(direct->dev, "Failed to read from file, %d\n", ret); + free(buf); + return ret; + } + + *buf_out = buf; + *len_hint = read_len; + + return 0; +} + +static int state_backend_bucket_direct_write(struct state_backend_storage_bucket + *bucket, const uint8_t * buf, + ssize_t len) +{ + struct state_backend_storage_bucket_direct *direct = + get_bucket_direct(bucket); + int ret; + struct state_backend_storage_bucket_direct_meta meta; + + if (direct->max_size && len > direct->max_size) + return -E2BIG; + + ret = lseek(direct->fd, direct->offset, SEEK_SET); + if (ret < 0) { + dev_err(direct->dev, "Failed to seek file, %d\n", ret); + return ret; + } + + meta.magic = direct_magic; + meta.written_length = len; + ret = write_full(direct->fd, &meta, sizeof(meta)); + if (ret < 0) { + dev_err(direct->dev, "Failed to write metadata to file, %d\n", ret); + return ret; + } + + ret = write_full(direct->fd, buf, len); + if (ret < 0) { + dev_err(direct->dev, "Failed to write file, %d\n", ret); + return ret; + } + + ret = flush(direct->fd); + if (ret < 0) { + dev_err(direct->dev, "Failed to flush file, %d\n", ret); + return ret; + } + + return 0; +} + +static void state_backend_bucket_direct_free(struct + state_backend_storage_bucket + *bucket) +{ + struct state_backend_storage_bucket_direct *direct = + get_bucket_direct(bucket); + + close(direct->fd); + free(direct); +} + +int state_backend_bucket_direct_create(struct device_d *dev, const char *path, + struct state_backend_storage_bucket **bucket, + off_t offset, ssize_t max_size) +{ + int fd; + struct state_backend_storage_bucket_direct *direct; + + fd = open(path, O_RDWR); + if (fd < 0) { + dev_err(dev, "Failed to open file '%s', %d\n", path, -errno); + close(fd); + return -errno; + } + + direct = xzalloc(sizeof(*direct)); + direct->offset = offset; + direct->max_size = max_size; + direct->fd = fd; + direct->dev = dev; + + direct->bucket.read = state_backend_bucket_direct_read; + direct->bucket.write = state_backend_bucket_direct_write; + direct->bucket.free = state_backend_bucket_direct_free; + *bucket = &direct->bucket; + + return 0; +} |