1 files changed, 34 insertions, 0 deletions
diff --git a/doc/whoami.c b/doc/whoami.c
new file mode 100644
index 0000000..59f9180
--- /dev/null
+++ b/doc/whoami.c
@@ -0,0 +1,34 @@
+/* whoami.c - a simple implementation of whoami utility */
+#include <pwd.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+who_am_i (void)
+{
+  struct passwd *pw;
+  char *user = NULL;
+
+  pw = getpwuid (geteuid ());
+  if (pw)
+    user = pw->pw_name;
+  else if ((user = getenv ("USER")) == NULL)
+    {
+      fprintf (stderr, "I don't know!\n");
+      return 1;
+    }
+  printf ("%s\n", user);
+  return 0;
+}
+
+int
+main (int argc, char **argv)
+{
+  if (argc > 1)
+    {
+      fprintf (stderr, "usage: whoami\n");
+      return 1;
+    }
+  return who_am_i ();
+}