add directory study

study/linux-travel/MINIX-1.5/1.5/Source/commands/ln.c

@@ -0,0 +1,64 @@
+/* ln - link a file		Author: Andy Tanenbaum */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+char name[256];
+struct stat stb;
+
+main(argc, argv)
+int argc;
+char **argv;
+{
+  char *file1, *file2;
+  char *last_comp();
+
+  if (argc < 2 || argc > 3) usage();
+  if (access(argv[1], 0) < 0) {
+	std_err("ln: cannot access ");
+	std_err(argv[1]);
+	std_err("\n");
+	exit(1);
+  }
+  if (stat(argv[1], &stb) >= 0 && (stb.st_mode & S_IFMT) == S_IFDIR) usage();
+  file1 = argv[1];
+
+  /* "ln file" means "ln file ." */
+  if (argc == 2)
+	file2 = ".";
+  else
+	file2 = argv[2];
+
+
+
+  /* Check to see if target is a directory. */
+  if (stat(file2, &stb) >= 0 && (stb.st_mode & S_IFMT) == S_IFDIR) {
+	strcpy(name, file2);
+	strcat(name, "/");
+	strcat(name, last_comp(file1));
+	file2 = name;
+  }
+  if (link(file1, file2)) {
+	std_err("ln: Can't link\n");
+	exit(1);
+  }
+  exit(0);
+}
+
+char *last_comp(s)
+char *s;
+{
+/* Return pointer to last component of string. */
+  int n;
+  n = strlen(s);
+  while (n--)
+	if (*(s + n) == '/') return(s + n + 1);
+  return(s);
+}
+
+
+usage()
+{
+  std_err("Usage: ln file1 [file2]\n");
+  exit(1);
+}