1 files changed, 34 insertions, 0 deletions
diff --git a/pc/chdirsaf.c b/pc/chdirsaf.c
new file mode 100644
index 0000000..0598f78
--- /dev/null
+++ b/pc/chdirsaf.c
@@ -0,0 +1,34 @@
+/* A safer version of chdir, which returns back to the
+   initial working directory when the program exits.  */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static char *initial_wd;
+
+static void
+restore_wd (void)
+{
+  chdir (initial_wd);
+}
+
+int
+chdir_safer (char const *dir)
+{
+  if (! initial_wd)
+    {
+      size_t s;
+      for (s = 256;  ! (initial_wd = getcwd (0, s));  s *= 2)
+	if (errno != ERANGE)
+	  return -1;
+      if (atexit (restore_wd) != 0)
+	{
+	  free (initial_wd);
+	  initial_wd = 0;
+	  return -1;
+	}
+    }
+
+  return chdir (dir);
+}