Patch for GNU touch to add -p option, a la mkdir

The other day I realized that often when I’m using touch, I’d like it to have the ability to create ancestor directories that don’t exist, a la mkdir -p. I quickly hacked together a shell script to do what I want.

Then I thought that this might be a generally useful extension to touch, so I thought I’d take a stab at adding it directly to the touch source code in GNU coreutils. Here’s my patch, which I sent to the mailing list:

--- coreutils-6.7.orig/src/touch.c      2006-10-22 09:54:15.000000000 -0700
+++ coreutils-6.7/src/touch.c   2006-12-28 15:35:28.000000000 -0800
@@ -34,6 +34,8 @@
 #include "safe-read.h"
 #include "stat-time.h"
 #include "utimens.h"
+#include "savewd.h"
+#include "mkdir-p.h"
 
 /* The official name of this program (e.g., no `g' prefix).  */
 #define PROGRAM_NAME "touch"
@@ -112,6 +114,62 @@
     error (EXIT_FAILURE, 0, _("invalid date format %s"), quote (flex_date));
 }
 
+/* 
+ */
+
+/* Options passed to subsidiary functions.  */
+struct mkdir_options
+{
+  /* Function to make an ancestor, or NULL if ancestors should not be
+     made.  */
+  int (*make_ancestor_function) (char const *, char const *, void *);
+
+  /* Mode for ancestor directory.  */
+  mode_t ancestor_mode;
+
+  /* Mode for directory itself.  */
+  mode_t mode;
+
+  /* File mode bits affected by MODE.  */
+  mode_t mode_bits;
+
+  /* If not null, format to use when reporting newly made directories.  */
+  char const *created_directory_format;
+};
+
+static struct mkdir_options global_mkdir_options;
+
+static void
+announce_mkdir (char const *dir, void *options)
+{
+  struct mkdir_options const *o = options;
+  if (o->created_directory_format)
+    error (0, 0, o->created_directory_format, quote (dir));
+}
+
+/* Make ancestor directory DIR, whose last component is COMPONENT,
+   with options OPTIONS.  Assume the working directory is COMPONENT's
+   parent.  Return 0 if successful and the resulting directory is
+   readable, 1 if successful but the resulting directory is not
+   readable, -1 (setting errno) otherwise.  */
+static int
+make_ancestor (char const *dir, char const *component, void *options)
+{
+  struct mkdir_options const *o = options;
+  int r = mkdir (component, o->ancestor_mode);
+  if (r == 0)
+    {
+      r = ! (o->ancestor_mode & S_IRUSR);
+      announce_mkdir (dir, options);
+    }
+  return r;
+}
+
+/*  */
+
 /* Update the time of file FILE according to the options given.
    Return true if successful.  */
 
@@ -129,6 +187,18 @@
     fd = STDOUT_FILENO;
   else if (! no_create)
     {
+      {
+        char *dir = dir_name (file);
+        struct savewd wd;
+        savewd_init (&wd);
+        void *make_ancestor_function = global_mkdir_options.make_ancestor_function;
+        mode_t mode = global_mkdir_options.mode;
+        mode_t mode_bits = global_mkdir_options.mode_bits;
+        make_dir_parents (dir, &wd, make_ancestor_function, &global_mkdir_options,
+                          mode, announce_mkdir,
+                          mode_bits, (uid_t) -1, (gid_t) -1, true);
+      }
+          
       /* Try to open FILE, creating it if necessary.  */
       fd = fd_reopen (STDIN_FILENO, file,
                      O_WRONLY | O_CREAT | O_NONBLOCK | O_NOCTTY,
@@ -246,6 +316,7 @@
   -m                     change only the modification time\n\
 "), stdout);
       fputs (_("\
+  -p, --parents          no error if existing, make parent directories as needed\n\
   -r, --reference=FILE   use this file's times instead of current time\n\
   -t STAMP               use [[CC]YY]MMDDhhmm[.ss] instead of current time\n\
   --time=WORD            change the specified time:\n\
@@ -272,6 +343,10 @@
   bool date_set = false;
   bool ok = true;
   char const *flex_date = NULL;
+  global_mkdir_options.make_ancestor_function = NULL;
+  global_mkdir_options.mode = S_IRWXUGO;
+  global_mkdir_options.mode_bits = 0;
+  global_mkdir_options.created_directory_format = NULL;
 
   initialize_main (&argc, &argv);
   program_name = argv[0];
@@ -284,7 +359,7 @@
   change_times = 0;
   no_create = use_ref = false;
 
-  while ((c = getopt_long (argc, argv, "acd:fmr:t:", longopts, NULL)) != -1)
+  while ((c = getopt_long (argc, argv, "acd:fmpr:t:", longopts, NULL)) != -1)
     {
       switch (c)
        {
@@ -307,6 +382,12 @@
          change_times |= CH_MTIME;
          break;
 
+        case 'p':
+          global_mkdir_options.make_ancestor_function = make_ancestor;
+          mode_t umask_value = umask (0);
+          global_mkdir_options.ancestor_mode = (S_IRWXUGO & ~umask_value) | (S_IWUSR | S_IXUSR);
+          break;
+
        case 'r':
          use_ref = true;
          ref_file = optarg;

and I also have this patch in Subversion here.

This feels fairly hacky to me, as there’s a fair amount of code duplication from mkdir.c – my hope is that the coreutils maintainers can take this and clean it up, perhaps by moving some of the common functionality into the lib directory.

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