chunk-db-local.c

#define _GNU_SOURCE
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>

#include "zunkfs.h"
#include "chunk-db.h"
#include "utils.h"

static bool local_read_chunk(unsigned char *chunk, const unsigned char *digest,
		void *db_info)
{
	char *chunk_dir = db_info;
	int fd, len, n;
	char *path;
	int err;

	err = asprintf(&path, "%s/%s", chunk_dir, digest_string(digest));
	if (err < 0)
		return false;

	TRACE("path=%s\n", path);

	fd = open(path, O_RDONLY);
	if (fd < 0) {
		WARNING("%s: %s\n", path, strerror(errno));
		free(path);
		return false;
	}
	free(path);

	len = 0;
	while (len < CHUNK_SIZE) {
		n = read(fd, chunk + len, CHUNK_SIZE - len);
		if (n < 0) {
			if (errno == EINTR)
				continue;
			WARNING("read %s: %s\n", path, strerror(errno));
			close(fd);
			return false;
		}
		len += n;
	}
	close(fd);

	return true;
}

static bool local_write_chunk(const unsigned char *chunk, 
		const unsigned char *digest, void *db_info)
{
	char *chunk_dir = db_info;
	int fd, len, n;
	char *path;
	int err;

	err = asprintf(&path, "%s/%s", chunk_dir, digest_string(digest));
	if (err < 0)
		return false;

	TRACE("path=%s\n", path);

	fd = open(path, O_WRONLY|O_CREAT, S_IRUSR|S_IWUSR);
	if (fd < 0) {
		WARNING("%s: %s\n", path, strerror(errno));
		free(path);
		return false;
	}
	free(path);

	len = 0;
	while (len < CHUNK_SIZE) {
		n = write(fd, chunk + len, CHUNK_SIZE - len);
		if (n < 0) {
			if (errno == EINTR)
				continue;
			WARNING("%s: %s\n", path, strerror(errno));
			close(fd);
			return false;
		}
		len += n;
	}
	err = close(fd);
	if (err)
		return false;

	return true;
}

static char *local_chunkdb_ctor(const char *spec, struct chunk_db *cdb)
{
	struct stat stbuf;
	int err;

	TRACE("mode=0x%x spec=%s\n", cdb->mode, spec);

	err = stat(spec, &stbuf);
	if (err == -1)
		return sprintf_new("Can't stat %s: %s.", spec, strerror(errno));
	if (!S_ISDIR(stbuf.st_mode))
		return sprintf_new("%s is not a directory.", spec);
	if (access(spec, R_OK | ((cdb->mode & CHUNKDB_RW) ? W_OK : 0)))
		return sprintf_new("%s.", strerror(errno));

	cdb->db_info = (void *)spec;

	return NULL;
}

static struct chunk_db_type local_chunkdb_type = {
	.spec_prefix = "dir:",
	.info_size = 0,
	.ctor = local_chunkdb_ctor,
	.read_chunk = local_read_chunk,
	.write_chunk = local_write_chunk,
	.help =
"   dir:<path>              Chunks are stored in specified directory.\n"
};

REGISTER_CHUNKDB(local_chunkdb_type);