start to impliment mscp as a library

this commit starts to refactor file.h|c to path.h|c and
add mscp.c|h. not completed yet.

src/mscp.c

@@ -0,0 +1,190 @@
+#include <stdbool.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/time.h>
+#include <sys/ioctl.h>
+#include <math.h>
+#include <pthread.h>
+
+#include <list.h>       
+#include <util.h>       
+#include <ssh.h>                
+#include <path.h>
+#include <pprint.h>             
+#include <atomic.h>             
+#include <platform.h>
+#include <mscp.h>
+
+struct mscp {
+	const char		*remote;	/* remote host (and uername) */
+	struct mscp_opts	*opts;
+	struct ssh_opts		ssh_opts;
+
+	sftp_session		first;		/* first sftp session */
+
+	char 			dst_path[PATH_MAX];
+	struct list_head	src_list;
+	struct list_head	path_list;
+	struct list_head	chunk_list;
+	lock			chunk_lock;
+
+	struct mscp_thread	*threads;
+};
+
+struct src {
+	struct list_head list;
+	char *path;
+};
+
+#define DEFAULT_MIN_CHUNK_SZ    (64 << 20)      /* 64MB */
+#define DEFAULT_NR_AHEAD        32
+#define DEFAULT_BUF_SZ          16384
+
+struct mscp *mscp_init(const char *remote_host, struct mscp_opts *opts)
+{
+	struct mscp *m;
+
+	m = malloc(sizeof(*m));
+	if (!m) {
+		pr_err("failed to allocate memory: %s\n", strerrno());
+		return NULL;
+	}
+
+	memset(m, 0, sizeof(*m));
+	INIT_LIST_HEAD(&m->src_list);
+	INIT_LIST_HEAD(&m->path_list);
+	INIT_LIST_HEAD(&m->chunk_list);
+	lock_init(&m->chunk_lock);
+	m->remote = strdup(remote_host);
+	if (!m->remote) {
+		pr_err("failed to allocate memory: %s\n", strerrno());
+		free(m);
+		return NULL;
+	}
+
+	m->opts = opts;
+	m->ssh_opts.login_name		= opts->ssh_login_name;
+	m->ssh_opts.port		= opts->ssh_port;
+	m->ssh_opts.identity		= opts->ssh_identity;
+	m->ssh_opts.cipher		= opts->ssh_cipher_spec;
+	m->ssh_opts.hmac		= opts->ssh_hmac_spec;
+	m->ssh_opts.compress		= opts->ssh_compress_level;
+	m->ssh_opts.debuglevel		= opts->ssh_debug_level;
+	m->ssh_opts.no_hostkey_check	= opts->ssh_no_hostkey_check;
+	m->ssh_opts.nodelay		= opts->ssh_disable_tcp_nodely;
+
+	m->first = ssh_init_sftp_session(m->remote, &m->ssh_opts);
+	if (!m->first) {
+		free(m);
+		return NULL;
+	}
+
+	return m;
+}
+
+int mscp_add_src_path(struct mscp *m, const char *src_path)
+{
+	struct src *s;
+
+	s = malloc(sizeof(*s));
+	if (!s) {
+		pr_err("failed to allocate memory: %s\n", strerrno());
+		return -1;
+	}
+
+	memset(s, 0, sizeof(*s));
+	s->path = strdup(src_path);
+	if (!s->path) {
+		pr_err("failed to allocate memory: %s\n", strerrno());
+		free(s);
+		return -1;
+	}
+
+	list_add_tail(&s->list, &m->src_list);
+	return 0;
+}
+
+static void mscp_free_src_list(struct mscp *m)
+{
+	struct src *s, *n;
+
+	list_for_each_entry_safe(s, n, &m->src_list, list) {
+		free(s->path);
+		list_del(&s->list);
+		free(s);
+	}
+}
+
+int mscp_set_dst_path(struct mscp *m, const char *dst_path)
+{
+	if (strlen(dst_path) + 1 >= PATH_MAX) {
+		pr_err("too long dst path: %s\n", dst_path);
+		return -1;
+	}
+
+	strncpy(m->dst_path, dst_path, PATH_MAX);
+	return 0;
+}
+
+int mscp_prepare(struct mscp *m)
+{
+	sftp_session src_sftp = NULL, dst_sftp = NULL;
+	bool src_path_is_dir, dst_path_is_dir;
+	struct list_head tmp;
+	struct src *s;
+	mstat ss, ds;
+	
+	switch (m->opts->direct) {
+	case MSCP_DIRECT_L2R:
+		src_sftp = NULL;
+		dst_sftp = m->first;
+		break;
+	case MSCP_DIRECT_R2L:
+		src_sftp = m->first;
+		dst_sftp = NULL;
+		break;
+	default:
+		pr_err("invalid mscp direction: %d\n", m->opts->direct);
+		return -1;
+	}
+
+	if (mscp_stat(m->dst_path, &ds, dst_sftp) == 0) {
+		if (mstat_is_dir(ds))
+			dst_path_is_dir = true;
+		mscp_stat_free(ds);
+	} else
+		dst_path_is_dir = false;
+
+	/* walk a src_path recusively, and resolve path->dst_path for each src */
+	list_for_each_entry(s, &m->src_list, list) {
+		if (mscp_stat(s->path, &ss, src_sftp) < 0) {
+			pr_err("stat: %s\n", mscp_stat_strerror(src_sftp));
+			return -1;
+		}
+		src_path_is_dir = mstat_is_dir(ss);
+		mscp_stat_free(ss);
+
+		INIT_LIST_HEAD(&tmp);
+		if (walk_src_path(src_sftp, s->path, &tmp) < 0)
+			return -1;
+		
+		if (resolve_dst_path(src_sftp, s->path, m->dst_path, &tmp,
+				     src_path_is_dir, dst_path_is_dir) < 0)
+			return -1;
+
+		list_splice_tail(&tmp, m->path_list.prev);
+	}
+
+	if (prepare_chunk(&m->path_list, &m->chunk_list, m->opts->nr_threads,
+			  m->opts->max_chunk_sz, m->opts->min_chunk_sz) < 0)
+		return -1;
+
+	mscp_free_src_list(m);
+
+	return 0;
+}
+
+int mscp_start(struct mscp *m)
+{
+	return 0;
+}