fixes #265 nngcat should support persistent ZT nodes

fixes #267 zerotier transport should lock ZT_HOME

9 files changed, 157 insertions, 32 deletions

diff --git a/src/core/file.c b/src/core/file.c
index 4715be2a..b76fdcda 100644
--- a/src/core/file.c
+++ b/src/core/file.c
@@ -128,4 +128,32 @@ const char *
 nni_file_basename(const char *path)
 {
 	return (nni_plat_file_basename(path));
+}
+
+struct nni_file_lockh {
+	nni_plat_flock lk;
+};
+
+int
+nni_file_lock(const char *path, nni_file_lockh **hp)
+{
+	nni_file_lockh *h;
+	int             rv;
+	if ((h = NNI_ALLOC_STRUCT(h)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	rv = nni_plat_file_lock(path, &h->lk);
+	if (rv != 0) {
+		NNI_FREE_STRUCT(h);
+		return (rv);
+	}
+	*hp = h;
+	return (0);
+}
+
+void
+nni_file_unlock(nni_file_lockh *h)
+{
+	nni_plat_file_unlock(&h->lk);
+	NNI_FREE_STRUCT(h);
 }
\ No newline at end of file
diff --git a/src/core/file.h b/src/core/file.h
index 7969ae5f..3baa1ccd 100644
--- a/src/core/file.h
+++ b/src/core/file.h
@@ -84,4 +84,10 @@ extern bool nni_file_is_file(const char *);
 // false if an error occurs, or the path references something else.
 extern bool nni_file_is_dir(const char *);
 
+typedef struct nni_file_lockh nni_file_lockh;
+
+extern int nni_file_lock(const char *, nni_file_lockh **);
+
+extern void nni_file_unlock(nni_file_lockh *);
+
 #endif // CORE_FILE_H
diff --git a/src/core/platform.h b/src/core/platform.h
index 3f336f11..d5fc40f7 100644
--- a/src/core/platform.h
+++ b/src/core/platform.h
@@ -434,6 +434,18 @@ typedef int (*nni_plat_file_walker)(const char *, void *);
 // with the path name, and the supplied void * argument.
 extern int nni_plat_file_walk(const char *, nni_plat_file_walker, void *, int);
 
+typedef struct nni_plat_flock nni_plat_flock;
+
+// nni_plat_file_lock locks the file.  This usually means open it (creating
+// if it does not exist) and doing a lock operation.  The nni_plat_flock
+// is our handle for the lock, to unlock.  Usually its just a file descriptor,
+// and we can unlock by doing close().  Note that this is a "try-lock"
+// operation -- if the file is already locked then NNG_EBUSY is returned.
+extern int nni_plat_file_lock(const char *path, nni_plat_flock *);
+
+// nni_plat_file_unlock unlocks the previously locked file.
+extern void nni_plat_file_unlock(nni_plat_flock *);
+
 // nni_plat_dir_open attempts to "open a directory" for listing.  The
 // handle for further operations is returned in the first argument, and
 // the directory name is supplied in the second.
diff --git a/src/platform/posix/posix_file.c b/src/platform/posix/posix_file.c
index 7863fdee..83d045fa 100644
--- a/src/platform/posix/posix_file.c
+++ b/src/platform/posix/posix_file.c
@@ -260,6 +260,33 @@ nni_plat_file_basename(const char *path)
 	return (path);
 }
 
+int
+nni_plat_file_lock(const char *path, nni_plat_flock *lk)
+{
+	int fd;
+	if ((fd = open(path, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR)) < 0) {
+		return (nni_plat_errno(errno));
+	}
+	if (lockf(fd, F_TLOCK, 0) < 0) {
+		int rv = errno;
+		close(fd);
+		if (rv == EAGAIN) {
+			return (NNG_EBUSY);
+		}
+		return (nni_plat_errno(rv));
+	}
+	lk->fd = fd;
+	return (0);
+}
+
+void
+nni_plat_file_unlock(nni_plat_flock *lk)
+{
+	int fd = lk->fd;
+	lk->fd = -1;
+	(void) close(fd);
+}
+
 char *
 nni_plat_temp_dir(void)
 {
diff --git a/src/platform/posix/posix_impl.h b/src/platform/posix/posix_impl.h
index 0b2a09f0..3616c69b 100644
--- a/src/platform/posix/posix_impl.h
+++ b/src/platform/posix/posix_impl.h
@@ -76,6 +76,10 @@ struct nni_plat_thr {
 	void *arg;
 };
 
+struct nni_plat_flock {
+	int fd;
+};
+
 #define NNG_PLATFORM_DIR_SEP "/"
 
 #endif
diff --git a/src/platform/windows/win_debug.c b/src/platform/windows/win_debug.c
index 00e327db..a47e7b41 100644
--- a/src/platform/windows/win_debug.c
+++ b/src/platform/windows/win_debug.c
@@ -1,5 +1,6 @@
 //
-// Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
 // copy of which should be located in the distribution where this
@@ -83,9 +84,8 @@ nni_plat_errno(int errnum)
 static struct {
 	int win_err;
 	int nng_err;
-} nni_win_errnos[] =
-    {
-      // clang-format off
+} nni_win_errnos[] = {
+	// clang-format off
 	{ ERROR_FILE_NOT_FOUND,	    NNG_ENOENT	     },
 	{ ERROR_PATH_NOT_FOUND,	    NNG_ENOENT	     },
 	{ ERROR_ACCESS_DENIED,	    NNG_EPERM	     },
@@ -104,6 +104,7 @@ static struct {
 	{ ERROR_NO_DATA,	    NNG_ECLOSED	     },
 	{ ERROR_PIPE_NOT_CONNECTED, NNG_ECLOSED	     },
 	{ ERROR_OPERATION_ABORTED,  NNG_ECLOSED	     },
+	{ ERROR_SHARING_VIOLATION,  NNG_EBUSY        },
 	{ WAIT_TIMEOUT,		    NNG_ETIMEDOUT    },
 	{ WSAEINTR,		    NNG_EINTR	     },
 	{ WSAEBADF,		    NNG_ECLOSED	     },
@@ -143,8 +144,8 @@ static struct {
 
 	// Must be Last!!
 	{			 0,		   0 },
-      // clang-format on
-    };
+	// clang-format on
+};
 
 // This converts a Windows API error (from GetLastError()) to an
 // nng standard error code.
diff --git a/src/platform/windows/win_file.c b/src/platform/windows/win_file.c
index 2a9504aa..515647e0 100644
--- a/src/platform/windows/win_file.c
+++ b/src/platform/windows/win_file.c
@@ -342,4 +342,28 @@ nni_plat_file_basename(const char *name)
 	return (name);
 }
 
+int
+nni_plat_file_lock(const char *path, nni_plat_flock *lk)
+{
+	HANDLE h;
+
+	// On Windows we do not have to explicitly lock the file, the
+	// dwShareMode being set to zeor effectively prevents it.
+	h = CreateFile(path, GENERIC_WRITE, 0, NULL, OPEN_ALWAYS,
+	    FILE_ATTRIBUTE_NORMAL, NULL);
+	if (h == INVALID_HANDLE_VALUE) {
+		return (nni_win_error(GetLastError()));
+	}
+	lk->h = h;
+	return (0);
+}
+
+void
+nni_plat_file_unlock(nni_plat_flock *lk)
+{
+	HANDLE h = lk->h;
+	(void) CloseHandle(h);
+	lk->h = INVALID_HANDLE_VALUE;
+}
+
 #endif // NNG_PLATFORM_WINDOWS
\ No newline at end of file
diff --git a/src/platform/windows/win_impl.h b/src/platform/windows/win_impl.h
index 0c22c240..b3c4738f 100644
--- a/src/platform/windows/win_impl.h
+++ b/src/platform/windows/win_impl.h
@@ -75,6 +75,10 @@ struct nni_win_event {
 	nni_win_event_ops ops;
 };
 
+struct nni_plat_flock {
+	HANDLE h;
+};
+
 extern int nni_win_error(int);
 
 extern int  nni_win_event_init(nni_win_event *, nni_win_event_ops *, void *);
diff --git a/src/transport/zerotier/zerotier.c b/src/transport/zerotier/zerotier.c
index e31bf113..8f83881c 100644
--- a/src/transport/zerotier/zerotier.c
+++ b/src/transport/zerotier/zerotier.c
@@ -153,30 +153,31 @@ enum zt_errors {
 // them with a reference count, and uniquely identify them using the
 // homedir.
 struct zt_node {
-	char          zn_path[NNG_MAXADDRLEN]; // ought to be sufficient
-	ZT_Node *     zn_znode;
-	uint64_t      zn_self;
-	nni_list_node zn_link;
-	int           zn_closed;
-	nni_plat_udp *zn_udp4;
-	nni_plat_udp *zn_udp6;
-	nni_list      zn_eplist;
-	nni_list      zn_plist;
-	nni_idhash *  zn_ports;
-	nni_idhash *  zn_eps;
-	nni_idhash *  zn_lpipes;
-	nni_idhash *  zn_rpipes;
-	nni_idhash *  zn_peers; // indexed by remote address
-	nni_aio *     zn_rcv4_aio;
-	uint8_t *     zn_rcv4_buf;
-	nng_sockaddr  zn_rcv4_addr;
-	nni_aio *     zn_rcv6_aio;
-	uint8_t *     zn_rcv6_buf;
-	nng_sockaddr  zn_rcv6_addr;
-	nni_thr       zn_bgthr;
-	int64_t       zn_bgtime;
-	nni_cv        zn_bgcv;
-	nni_cv        zn_snd6_cv;
+	char            zn_path[NNG_MAXADDRLEN]; // ought to be sufficient
+	nni_file_lockh *zn_flock;
+	ZT_Node *       zn_znode;
+	uint64_t        zn_self;
+	nni_list_node   zn_link;
+	int             zn_closed;
+	nni_plat_udp *  zn_udp4;
+	nni_plat_udp *  zn_udp6;
+	nni_list        zn_eplist;
+	nni_list        zn_plist;
+	nni_idhash *    zn_ports;
+	nni_idhash *    zn_eps;
+	nni_idhash *    zn_lpipes;
+	nni_idhash *    zn_rpipes;
+	nni_idhash *    zn_peers; // indexed by remote address
+	nni_aio *       zn_rcv4_aio;
+	uint8_t *       zn_rcv4_buf;
+	nng_sockaddr    zn_rcv4_addr;
+	nni_aio *       zn_rcv6_aio;
+	uint8_t *       zn_rcv6_buf;
+	nng_sockaddr    zn_rcv6_addr;
+	nni_thr         zn_bgthr;
+	int64_t         zn_bgtime;
+	nni_cv          zn_bgcv;
+	nni_cv          zn_snd6_cv;
 };
 
 // The fragment list is used to keep track of incoming received
@@ -300,7 +301,7 @@ static void
 zt_bgthr(void *arg)
 {
 	zt_node *ztn = arg;
-	int64_t now;
+	int64_t  now;
 
 	nni_mtx_lock(&zt_lk);
 	for (;;) {
@@ -559,7 +560,7 @@ zt_send(zt_node *ztn, uint64_t nwid, uint8_t op, uint64_t raddr,
 {
 	uint64_t srcmac = zt_node_to_mac(laddr >> 24, nwid);
 	uint64_t dstmac = zt_node_to_mac(raddr >> 24, nwid);
-	int64_t now     = zt_now();
+	int64_t  now    = zt_now();
 
 	NNI_ASSERT(len >= zt_size_headers);
 	data[zt_offset_op]    = op;
@@ -1422,6 +1423,9 @@ zt_node_destroy(zt_node *ztn)
 	if (ztn->zn_rcv6_buf != NULL) {
 		nni_free(ztn->zn_rcv6_buf, zt_rcv_bufsize);
 	}
+	if (ztn->zn_flock != NULL) {
+		nni_file_unlock(ztn->zn_flock);
+	}
 	nni_aio_fini(ztn->zn_rcv4_aio);
 	nni_aio_fini(ztn->zn_rcv6_aio);
 	nni_idhash_fini(ztn->zn_eps);
@@ -1480,6 +1484,21 @@ zt_node_create(zt_node **ztnp, const char *path)
 		return (rv);
 	}
 
+	if (strlen(path) > 0) {
+		char *lkfile;
+		if ((lkfile = nni_file_join(path, "lock")) == NULL) {
+			zt_node_destroy(ztn);
+			return (NNG_ENOMEM);
+		}
+
+		if ((rv = nni_file_lock(lkfile, &ztn->zn_flock)) != 0) {
+			zt_node_destroy(ztn);
+			nni_strfree(lkfile);
+			return (rv);
+		}
+		nni_strfree(lkfile);
+	}
+
 	// Setup for dynamic ephemeral port allocations.  We
 	// set the range to allow for ephemeral ports, but not
 	// higher than the max port, and starting with an