New platform API for storage methods.

This includes converting the ZeroTier transport to use these.

The new API supports file creation, retrieval, and deletion. It
also supports directory methods for traversal, creation, and
deletion.  It also has a few methods to obtain well-known directories
like $TMPDIR and $HOME.

A rich test suite for this functionality is added as well.

1 files changed, 207 insertions, 0 deletions

diff --git a/src/platform/posix/posix_file.c b/src/platform/posix/posix_file.c
new file mode 100644
index 00000000..d7033095
--- /dev/null
+++ b/src/platform/posix/posix_file.c
@@ -0,0 +1,207 @@
+//
+// Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2017 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
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+#include "core/nng_impl.h"
+
+#ifdef NNG_PLATFORM_POSIX
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+// File support.
+
+// nni_plat_file_put writes the named file, with the provided data,
+// and the given size.  If the file already exists it is overwritten.
+// The permissions on the file should be limited to read and write
+// access by the entity running the application only.
+int
+nni_plat_file_put(const char *name, const void *data, size_t len)
+{
+	FILE *f;
+	int   rv = 0;
+
+	if ((f = fopen(name, "wb")) == NULL) {
+		return (nni_plat_errno(errno));
+	}
+	if (fwrite(data, 1, len, f) != len) {
+		rv = nni_plat_errno(errno);
+		(void) unlink(name);
+	}
+	(void) fclose(f);
+	return (rv);
+}
+
+// nni_plat_file_get reads the entire named file, allocating storage
+// to receive the data and returning the data and the size in the
+// reference arguments.
+int
+nni_plat_file_get(const char *name, void **datap, size_t *lenp)
+{
+	FILE *      f;
+	struct stat st;
+	int         rv = 0;
+	int         len;
+	void *      data;
+
+	if ((f = fopen(name, "rb")) == NULL) {
+		return (nni_plat_errno(errno));
+	}
+
+	if (stat(name, &st) != 0) {
+		rv = nni_plat_errno(errno);
+		(void) fclose(f);
+		return (rv);
+	}
+
+	len = st.st_size;
+	if ((data = nni_alloc(len)) == NULL) {
+		rv = NNG_ENOMEM;
+		goto done;
+	}
+	if (fread(data, 1, len, f) != len) {
+		rv = nni_plat_errno(errno);
+		nni_free(data, len);
+		goto done;
+	}
+	*datap = data;
+	*lenp  = len;
+done:
+	(void) fclose(f);
+	return (rv);
+}
+
+// nni_plat_file_delete deletes the named file.
+int
+nni_plat_file_delete(const char *name)
+{
+	if (unlink(name) < 0) {
+		return (nni_plat_errno(errno));
+	}
+	return (0);
+}
+
+// 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.
+int
+nni_plat_dir_open(void **dirp, const char *name)
+{
+	DIR *dir;
+
+	if ((dir = opendir(name)) == NULL) {
+		return (nni_plat_errno(errno));
+	}
+	*dirp = dir;
+	return (0);
+}
+
+int
+nni_plat_dir_create(const char *name)
+{
+	if (mkdir(name, S_IRWXU) != 0) {
+		if (errno == EEXIST) {
+			return (0);
+		}
+		return (nni_plat_errno(errno));
+	}
+	return (0);
+}
+
+int
+nni_plat_dir_remove(const char *name)
+{
+	if (rmdir(name) != 0) {
+		if (errno == ENOENT) {
+			return (0);
+		}
+		return (nni_plat_errno(errno));
+	}
+	return (0);
+}
+
+// nni_plat_dir_next gets the next directory entry.  Each call returns
+// a new entry (arbitrary order).  When no more entries exist, it returns
+// NNG_ENOENT.
+int
+nni_plat_dir_next(void *dir, const char **namep)
+{
+	for (;;) {
+		struct dirent *ent;
+
+		if ((ent = readdir((DIR *) dir)) == NULL) {
+			return (NNG_ENOENT);
+		}
+		// Skip "." and ".."  -- we would like to skip all
+		// directories, but that would require checking full
+		// paths.
+		if ((strcmp(ent->d_name, ".") == 0) ||
+		    (strcmp(ent->d_name, "..") == 0)) {
+			continue;
+		}
+		*namep = ent->d_name;
+		return (0);
+	}
+}
+
+// nni_plat_dir_close closes the directory handle, freeing all
+// resources associated with it.
+void
+nni_plat_dir_close(void *dir)
+{
+	(void) closedir((DIR *) dir);
+}
+
+char *
+nni_plat_temp_dir(void)
+{
+	char *temp;
+
+	// POSIX says $TMPDIR is required.
+	if ((temp = getenv("TMPDIR")) != NULL) {
+		return (nni_strdup(temp));
+	}
+	return (nni_strdup("/tmp"));
+}
+
+char *
+nni_plat_home_dir(void)
+{
+	char *home;
+
+	// POSIX says that $HOME is *REQUIRED*.  We could look in getpwuid,
+	// but realistically this is simply not required.
+	if ((home = getenv("HOME")) != NULL) {
+		return (nni_strdup(home));
+	}
+	return (NULL);
+}
+
+char *
+nni_plat_join_dir(const char *prefix, const char *suffix)
+{
+	char * newdir;
+	size_t len;
+
+	len    = strlen(prefix) + strlen(suffix) + 2;
+	newdir = nni_alloc(strlen(prefix) + strlen(suffix) + 2);
+	if (newdir != NULL) {
+		(void) snprintf(newdir, len, "%s/%s", prefix, suffix);
+	}
+	return (newdir);
+}
+
+#endif // NNG_PLATFORM_POSIX