1 files changed, 92 insertions, 0 deletions
diff --git a/newlib/libc/sys/linux/realpath.c b/newlib/libc/sys/linux/realpath.c
new file mode 100644
index 0000000..8aa5eb4
--- /dev/null
+++ b/newlib/libc/sys/linux/realpath.c
@@ -0,0 +1,92 @@
+/* realpath.c - Return the canonicalized absolute pathname */
+
+/* Written 2000 by Werner Almesberger */
+
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <limits.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+
+/* FIXME: buffer overrun possible, loops forever on cyclic symlinks */
+
+
+/*
+ * Canonical name: never ends with a slash
+ */
+
+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) {
+	char *slash;
+	struct stat st;
+
+	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];
+
+		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];
+    char *path_copy;
+    int res;
+
+    if (!*path) {
+	errno = ENOENT; /* SUSv2 */
+	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;
+}