mktemp: make argument optional (coreutil 6.12 compat)

function                                             old     new   delta
mktemp_main                                          157     174     +17
packed_usage                                       24508   24504      -4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 17/-4)              Total: 13 bytes

2 files changed, 35 insertions, 17 deletions

diff --git a/debianutils/mktemp.c b/debianutils/mktemp.c
index b011fc10c..de27d3023 100644
--- a/debianutils/mktemp.c
+++ b/debianutils/mktemp.c
@@ -9,34 +9,53 @@
  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  */
 
+/* Coreutils 6.12 man page says:
+ *        mktemp [OPTION]... [TEMPLATE]
+ * Create a temporary file or directory, safely, and print its name. If
+ * TEMPLATE is not specified, use tmp.XXXXXXXXXX.
+ * -d, --directory
+ *        create a directory, not a file
+ * -q, --quiet
+ *        suppress diagnostics about file/dir-creation failure
+ * -u, --dry-run
+ *        do not create anything; merely print a name (unsafe)
+ * --tmpdir[=DIR]
+ *        interpret TEMPLATE relative to DIR. If DIR is not specified,
+ *        use  $TMPDIR if set, else /tmp.  With this option, TEMPLATE must
+ *        not be an absolute name. Unlike with -t, TEMPLATE may contain
+ *        slashes, but even here, mktemp still creates only the final com-
+ *        ponent.
+ * -p DIR use DIR as a prefix; implies -t [deprecated]
+ * -t     interpret TEMPLATE as a single file name component, relative  to
+ *        a  directory:  $TMPDIR, if set; else the directory specified via
+ *        -p; else /tmp [deprecated]
+ */
+
+
 #include "libbb.h"
 
 int mktemp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int mktemp_main(int argc ATTRIBUTE_UNUSED, char **argv)
 {
-        // -d      Make a directory instead of a file
-        // -q      Fail silently if an error occurs [bbox: ignored]
-        // -t      Generate a path rooted in temporary directory
-        // -p DIR  Use DIR as a temporary directory (implies -t)
         const char *path;
         char *chp;
-        unsigned flags;
+        unsigned opt;
 
-        opt_complementary = "=1"; /* exactly one arg */
-        flags = getopt32(argv, "dqtp:", &path);
-        chp = argv[optind];
+        opt_complementary = "?1"; /* 1 argument max */
+        opt = getopt32(argv, "dqtp:", &path);
+        chp = argv[optind] ? argv[optind] : xstrdup("tmp.XXXXXXXXXX");
 
-        if (flags & (4|8)) { /* -t and/or -p */
+        if (opt & (4|8)) { /* -t and/or -p */
                 const char *dir = getenv("TMPDIR");
                 if (dir && *dir != '\0')
                         path = dir;
-                else if (!(flags & 8)) /* No -p */
+                else if (!(opt & 8)) /* no -p */
                         path = "/tmp/";
                 /* else path comes from -p DIR */
                 chp = concat_path_file(path, chp);
         }
 
-        if (flags & 1) { /* -d */
+        if (opt & 1) { /* -d */
                 if (mkdtemp(chp) == NULL)
                         return EXIT_FAILURE;
         } else {
diff --git a/include/usage.h b/include/usage.h
index 2e5321306..f9a831e85 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2542,19 +2542,18 @@
 #endif
 
 #define mktemp_trivial_usage \
-       "[-dt] [-p DIR] TEMPLATE"
+       "[-dt] [-p DIR] [TEMPLATE]"
 #define mktemp_full_usage "\n\n" \
-       "Create a temporary file with its name based on TEMPLATE.\n" \
-       "TEMPLATE is any name with six 'Xs' (i.e., /tmp/temp.XXXXXX).\n" \
+       "Create a temporary file with name based on TEMPLATE and print its name.\n" \
+       "TEMPLATE must end with XXXXXX (i.e., /tmp/temp.XXXXXX).\n" \
      "\nOptions:" \
      "\n        -d      Make a directory instead of a file" \
 /*   "\n        -q      Fail silently if an error occurs" - we ignore it */ \
      "\n        -t      Generate a path rooted in temporary directory" \
      "\n        -p DIR  Use DIR as a temporary directory (implies -t)" \
      "\n" \
-     "\n" \
-       "For -t or -p, directory is chosen as follows:\n" \
-       "$TMPDIR if set, else -p DIR, else /tmp" \
+     "\nFor -t or -p, directory is chosen as follows:" \
+     "\n$TMPDIR if set, else -p DIR, else /tmp" \
 
 #define mktemp_example_usage \
        "$ mktemp /tmp/temp.XXXXXX\n" \