[GitHub] [incubator-nuttx] yamt commented on a change in pull request #1486: libc: Implement ftw and nftw function

[GitBox <gi...@apache.org>]

yamt commented on a change in pull request #1486:
URL: https://github.com/apache/incubator-nuttx/pull/1486#discussion_r462845578



##########
File path: libs/libc/dirent/lib_nftw.c
##########
@@ -0,0 +1,228 @@
+/****************************************************************************
+ * libs/libc/dirent/lib_nftw.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <ftw.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <limits.h>
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static int
+call_nftw(FAR char *path, nftw_cb_t fn, int flags, int base,
+          int level, FAR const struct stat *buf, int info)
+{
+  struct FTW ftw =
+  {
+    base, level
+  };
+
+  if (flags & FTW_CHDIR)
+    {
+      int r;
+
+      if (base > 1)
+        {
+          path[base - 1] = '\0';
+          r = chdir(path);
+          path[base - 1] = '/';
+        }
+      else
+        {
+          r = chdir("/");
+        }
+
+      if (r < 0)
+        {
+          return r;
+        }
+    }
+
+  return fn(path, buf, info, &ftw);
+}
+
+static int
+do_nftw(FAR char *path, nftw_cb_t fn, int fdlimit, int flags, int level)
+{
+  DIR *dir = NULL;
+  struct stat buf;
+  size_t base;
+  size_t j;
+  int info;
+  int r;
+
+  j = strlen(path);
+  while (j > 1 && path[j - 1] == '/')
+    {
+      path[--j] = '\0';
+    }
+
+  base = j - 1;
+  while (base > 0 && path[base - 1] != '/')
+    {
+      --base;
+    }
+
+  r = flags & FTW_PHYS ? lstat(path, &buf) : stat(path, &buf);
+  if (r < 0)
+    {
+      if (!(flags & FTW_PHYS) &&
+          get_errno() == ENOENT && !lstat(path, &buf))
+        {
+          info = FTW_SLN;
+        }
+      else if (get_errno() == EACCES)
+        {
+          info = FTW_NS;
+        }
+      else
+        {
+          return -1;
+        }
+    }
+  else if (S_ISDIR(buf.st_mode))
+    {
+      if (flags & FTW_DEPTH)
+        {
+          info = FTW_DP;
+        }
+      else
+        {
+          info = FTW_D;
+        }
+    }
+  else if (S_ISLNK(buf.st_mode))
+    {
+      if (flags & FTW_PHYS)
+        {
+          info = FTW_SL;
+        }
+      else
+        {
+          info = FTW_SLN;
+        }
+    }
+  else
+    {
+      info = FTW_F;
+    }
+
+  if (info == FTW_D || info == FTW_DP)
+    {
+      dir = opendir(path);
+      if (dir)
+        {
+          if (fdlimit <= 0)
+            {
+              closedir(dir);
+              dir = NULL;
+            }
+        }
+      else if (get_errno() == EACCES)
+        {
+          info = FTW_DNR;
+        }
+      else
+        {
+          return -1;
+        }
+    }
+
+  if (!(flags & FTW_DEPTH))
+    {
+      r = call_nftw(path, fn, flags, base, level, &buf, info);
+      if (r)
+        {
+          return r;
+        }
+    }
+
+  if (dir)
+    {
+      struct dirent *de;
+      size_t l = j;
+
+      if (path[j - 1] != '/')
+        {
+          path[j++] = '/';
+        }
+
+      while ((de = readdir(dir)))
+        {
+          if (de->d_name[0] == '.' && (!de->d_name[1] ||
+              (de->d_name[1] == '.' && !de->d_name[2])))
+            {
+              continue;
+            }
+
+          if (strlen(de->d_name) > PATH_MAX - j)
+            {
+              set_errno(ENAMETOOLONG);
+              closedir(dir);
+              return -1;
+            }
+
+          strcpy(path + j, de->d_name);
+          r = do_nftw(path, fn, fdlimit - 1, flags, level + 1);
+          if (r)
+            {
+              closedir(dir);
+              return r;
+            }
+        }
+
+      path[l] = '\0';
+      closedir(dir);
+    }
+
+  if (flags & FTW_DEPTH)
+    {
+      r = call_nftw(path, fn, flags, base, level, &buf, info);
+      if (r)
+        {
+          return r;
+        }
+    }
+
+  return 0;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+int nftw(FAR const char *path, nftw_cb_t fn, int fdlimit, int flags)
+{
+  char pathbuf[PATH_MAX + 1];
+
+  strncpy(pathbuf, path, PATH_MAX);
+  pathbuf[PATH_MAX] = '\0';
+
+  return do_nftw(pathbuf, fn, fdlimit, flags, 0);
+}

Review comment:
       i guess it's supposed to restore the original cwd when finished.
   

##########
File path: libs/libc/dirent/lib_nftw.c
##########
@@ -0,0 +1,228 @@
+/****************************************************************************
+ * libs/libc/dirent/lib_nftw.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <ftw.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <limits.h>
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static int
+call_nftw(FAR char *path, nftw_cb_t fn, int flags, int base,
+          int level, FAR const struct stat *buf, int info)
+{
+  struct FTW ftw =
+  {
+    base, level
+  };
+
+  if (flags & FTW_CHDIR)
+    {
+      int r;
+
+      if (base > 1)
+        {
+          path[base - 1] = '\0';
+          r = chdir(path);
+          path[base - 1] = '/';
+        }

Review comment:
       does this work when the user-given path is relative?




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