[PATCH 028/114] Add implementation for realpath function for Phoenix.

[Jakub Sejdak <jakub dot sejdak at phoesys dot com>]

From: Kuba Sejdak <jakub.sejdak@phoesys.com>

---
 newlib/libc/sys/phoenix/realpath.c | 122 +++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 newlib/libc/sys/phoenix/realpath.c

diff --git a/newlib/libc/sys/phoenix/realpath.c b/newlib/libc/sys/phoenix/realpath.c
new file mode 100644
index 0000000..01220fe
--- /dev/null
+++ b/newlib/libc/sys/phoenix/realpath.c
@@ -0,0 +1,122 @@
+/* Copyright (C) 2012-2016 Phoenix Systems (http://www.phoesys.com/).
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/* Written 2000 by Werner Almesberger */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/dirent.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+static int resolve_path(char *path, char *result, char *pos)
+{
+	if (*path == '/') {
+		*result = '/';
+		pos = result+1;
+		++path;
+	}
+
+	*pos = 0;
+	if (!*path)
+		return 0;
+
+	while (1) {
+		struct stat st;
+
+		char *slash = *path ? strchr(path,'/') : NULL;
+		if (slash)
+			*slash = 0;
+
+		if (!path[0] || (path[0] == '.' &&	(!path[1] || (path[1] == '.' && !path[2])))) {
+			--pos;
+			if (pos != result && path[0] && path[1])
+				while (*--pos != '/');
+		}
+		else {
+			strcpy(pos,path);
+			if (lstat(result,&st) < 0)
+				return -1;
+
+			if (S_ISLNK(st.st_mode)) {
+				char buf[PATH_MAX_SIZE];
+
+				if (readlink(result,buf,sizeof(buf)) < 0)
+					return -1;
+				
+				*pos = 0;
+				if (slash) {
+					*slash = '/';
+					strcat(buf, slash);
+				}
+	
+				strcpy(path,buf);
+				if (*path == '/')
+					result[1] = 0;
+
+				pos = strchr(result,0);
+				continue;
+			}
+
+			pos = strchr(result,0);
+		}
+	
+		if (slash) {
+	    	*pos++ = '/';
+	    	path = slash + 1;
+		}
+
+		*pos = 0;
+		if (!slash)
+			break;
+    }
+
+	return 0;
+}
+
+char *realpath(const char *path, char *resolved_path)
+{
+	char cwd[PATH_MAX_SIZE];
+	char *path_copy;
+	int res;
+
+	if (!*path) {
+		errno = ENOENT;
+		return NULL;
+	}
+
+	if (!getcwd(cwd, sizeof(cwd)))
+		return NULL;
+    
+	strcpy(resolved_path, "/");
+	if (resolve_path(cwd, resolved_path, resolved_path))
+		return NULL;
+
+	strcat(resolved_path, "/");
+	path_copy = strdup(path);
+	if (!path_copy)
+		return NULL;
+
+	res = resolve_path(path_copy, resolved_path, strchr(resolved_path, 0));
+	free(path_copy);
+	if (res)
+		return NULL;
+
+	return resolved_path;
+}
-- 
2.5.0