mktemp: add suffix handling

Now that mkstemps is supported, we might as well use it.

* src/mktemp.c (TMPDIR_OPTION): New enum value.
(longopts): Add new option.
(usage): Document it.
(count_trailing_X_s): Rename...
(count_consecutive_X_s): ...to this, and add parameter.
(mkstemp_len, mkdtemp_len): Add parameter.
(main): Implement new option.
(AUTHORS): Add myself.
* AUTHORS (mktemp): Likewise.
* tests/misc/mktemp: Test new option.
* doc/coreutils.texi (mktemp invocation): Document it.
* NEWS: Likewise.
Fixes http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=548316.

5 files changed, 160 insertions, 27 deletions

diff --git a/AUTHORS b/AUTHORS
index 7095db09a..59a0dfa0a 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -46,7 +46,7 @@ md5sum: Ulrich Drepper, Scott Miller, David Madore
 mkdir: David MacKenzie
 mkfifo: David MacKenzie
 mknod: David MacKenzie
-mktemp: Jim Meyering
+mktemp: Jim Meyering, Eric Blake
 mv: Mike Parker, David MacKenzie, Jim Meyering
 nice: David MacKenzie
 nl: Scott Bartram, David MacKenzie
diff --git a/NEWS b/NEWS
index 07eecab1f..5b75dbbd9 100644
--- a/NEWS
+++ b/NEWS
@@ -70,6 +70,10 @@ GNU coreutils NEWS                                    -*- outline -*-
   md5sum --check now also accepts openssl-style checksums.
   So do sha1sum, sha224sum, sha384sum and sha512sum.
 
+  mktemp now accepts the option --suffix to provide a known suffix
+  after the substitution in the template.  Additionally, uses such as
+  "mktemp fileXXXXXX.txt" are able to infer an appropriate --suffix.
+
   touch now accepts the option --no-dereference (-h), as a means to
   change symlink timestamps on platforms with enough support.
 
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 6126cf8cd..227014cd4 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -12068,12 +12068,12 @@ mktemp [@var{option}]@dots{} [@var{template}]
 @end example
 
 Safely create a temporary file or directory based on @var{template},
-and print its name.  If given, @var{template} must end in at least
-three consecutive @samp{X}s.  If omitted, the template
+and print its name.  If given, @var{template} must include at least
+three consecutive @samp{X}s in the last component.  If omitted, the template
 @samp{tmp.XXXXXXXXXX} is used, and option @option{--tmpdir} is
-implied.  The trailing @samp{X}s in the @var{template} will be replaced
+implied.  The final run of @samp{X}s in the @var{template} will be replaced
 by alpha-numeric characters; thus, on a case-sensitive file system,
-and with a @var{template} ending in @var{n} instances of @samp{X},
+and with a @var{template} including a run of @var{n} instances of @samp{X},
 there are @samp{62**@var{n}} potential file names.
 
 Older scripts used to create temporary files by simply joining the
@@ -12108,6 +12108,15 @@ file.H47c
 @end example
 
 @item
+Create a temporary file with a known suffix.
+@example
+$ mktemp --suffix=.txt file-XXXX
+file-H08W.txt
+$ mktemp file-XXXX-XXXX.txt
+file-XXXX-eI9L.txt
+@end example
+
+@item
 Create a secure fifo relative to the user's choice of @env{TMPDIR},
 but falling back to the current directory rather than @file{/tmp}.
 Note that @command{mktemp} does not create fifos, but can create a
@@ -12186,6 +12195,16 @@ specified, @var{template} must not be absolute.  However,
 @var{template} can still contain slashes, although intermediate
 directories must already exist.
 
+@item --suffix=@var{suffix}
+@opindex --suffix
+Append @var{suffix} to the @var{template}.  @var{suffix} must not
+contain slash.  If @option{--suffix} is specified, @var{template} must
+end in @samp{X}; if it is not specified, then an appropriate
+@option{--suffix} is inferred by finding the last @samp{X} in
+@var{template}.  This option exists for use with the default
+@var{template} and for the creation of a @var{suffix} that starts with
+@samp{X}.
+
 @item -t
 @opindex -t
 Treat @var{template} as a single file relative to the value of
diff --git a/src/mktemp.c b/src/mktemp.c
index 6cf40b001..ac35026e8 100644
--- a/src/mktemp.c
+++ b/src/mktemp.c
@@ -14,7 +14,7 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-/* Written by Jim Meyering.  */
+/* Written by Jim Meyering and Eric Blake.  */
 
 #include <config.h>
 #include <stdio.h>
@@ -32,7 +32,9 @@
 /* The official name of this program (e.g., no `g' prefix).  */
 #define PROGRAM_NAME "mktemp"
 
-#define AUTHORS proper_name ("Jim Meyering")
+#define AUTHORS \
+  proper_name ("Jim Meyering"), \
+  proper_name ("Eric Blake")
 
 static const char *default_template = "tmp.XXXXXXXXXX";
 
@@ -40,7 +42,8 @@ static const char *default_template = "tmp.XXXXXXXXXX";
    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
 enum
 {
-  TMPDIR_OPTION = CHAR_MAX + 1
+  SUFFIX_OPTION = CHAR_MAX + 1,
+  TMPDIR_OPTION
 };
 
 static struct option const longopts[] =
@@ -48,6 +51,7 @@ static struct option const longopts[] =
   {"directory", no_argument, NULL, 'd'},
   {"quiet", no_argument, NULL, 'q'},
   {"dry-run", no_argument, NULL, 'u'},
+  {"suffix", required_argument, NULL, SUFFIX_OPTION},
   {"tmpdir", optional_argument, NULL, TMPDIR_OPTION},
   {GETOPT_HELP_OPTION_DECL},
   {GETOPT_VERSION_OPTION_DECL},
@@ -65,7 +69,7 @@ usage (int status)
       printf (_("Usage: %s [OPTION]... [TEMPLATE]\n"), program_name);
       fputs (_("\
 Create a temporary file or directory, safely, and print its name.\n\
-TEMPLATE must end in at least 3 consecutive `X's.\n\
+TEMPLATE must contain at least 3 consecutive `X's in last component.\n\
 If TEMPLATE is not specified, use tmp.XXXXXXXXXX, and --tmpdir is implied.\n\
 "), stdout);
       fputs ("\n", stdout);
@@ -75,6 +79,10 @@ If TEMPLATE is not specified, use tmp.XXXXXXXXXX, and --tmpdir is implied.\n\
   -q, --quiet         suppress diagnostics about file/dir-creation failure\n\
 "), stdout);
       fputs (_("\
+      --suffix=SUFF   append SUFF to TEMPLATE.  SUFF must not contain slash.\n\
+                        This option is implied if TEMPLATE does not end in X.\n\
+"), stdout);
+      fputs (_("\
       --tmpdir[=DIR]  interpret TEMPLATE relative to DIR.  If DIR is not\n\
                         specified, use $TMPDIR if set, else /tmp.  With\n\
                         this option, TEMPLATE must not be an absolute name.\n\
@@ -98,9 +106,8 @@ If TEMPLATE is not specified, use tmp.XXXXXXXXXX, and --tmpdir is implied.\n\
 }
 
 static size_t
-count_trailing_X_s (const char *s)
+count_consecutive_X_s (const char *s, size_t len)
 {
-  size_t len = strlen (s);
   size_t n = 0;
   for ( ; len && s[len-1] == 'X'; len--)
     ++n;
@@ -108,16 +115,16 @@ count_trailing_X_s (const char *s)
 }
 
 static int
-mkstemp_len (char *tmpl, size_t suff_len, bool dry_run)
+mkstemp_len (char *tmpl, size_t suff_len, size_t x_len, bool dry_run)
 {
-  return gen_tempname_len (tmpl, 0, 0, dry_run ? GT_NOCREATE : GT_FILE,
+  return gen_tempname_len (tmpl, suff_len, 0, dry_run ? GT_NOCREATE : GT_FILE,
                            suff_len);
 }
 
 static int
-mkdtemp_len (char *tmpl, size_t suff_len, bool dry_run)
+mkdtemp_len (char *tmpl, size_t suff_len, size_t x_len, bool dry_run)
 {
-  return gen_tempname_len (tmpl, 0, 0, dry_run ? GT_NOCREATE : GT_DIR,
+  return gen_tempname_len (tmpl, suff_len, 0, dry_run ? GT_NOCREATE : GT_DIR,
                            suff_len);
 }
 
@@ -130,12 +137,14 @@ main (int argc, char **argv)
   int c;
   unsigned int n_args;
   char *template;
+  char *suffix = NULL;
   bool use_dest_dir = false;
   bool deprecated_t_option = false;
   bool create_directory = false;
   bool dry_run = false;
   int status = EXIT_SUCCESS;
   size_t x_count;
+  size_t suffix_len;
   char *dest_name;
 
   initialize_main (&argc, &argv);
@@ -173,6 +182,10 @@ main (int argc, char **argv)
           dest_dir_arg = optarg;
           break;
 
+        case SUFFIX_OPTION:
+          suffix = optarg;
+          break;
+
         case_GETOPT_HELP_CHAR;
 
         case 'V': /* Undocumented alias.  FIXME: remove in 2011.  */
@@ -208,7 +221,41 @@ main (int argc, char **argv)
       template = argv[optind];
     }
 
-  x_count = count_trailing_X_s (template);
+  if (suffix)
+    {
+      size_t len = strlen (template);
+      if (!len || template[len - 1] != 'X')
+        {
+          error (EXIT_FAILURE, 0,
+                 _("with --suffix, template %s must end in X"),
+                 quote (template));
+        }
+      suffix_len = strlen (suffix);
+      dest_name = xcharalloc (len + suffix_len + 1);
+      memcpy (dest_name, template, len);
+      memcpy (dest_name + len, suffix, suffix_len + 1);
+      template = dest_name;
+      suffix = dest_name + len;
+    }
+  else
+    {
+      template = xstrdup (template);
+      suffix = strrchr (template, 'X');
+      if (!suffix)
+        suffix = strchr (template, '\0');
+      else
+        suffix++;
+      suffix_len = strlen (suffix);
+    }
+
+  /* At this point, template is malloc'd, and suffix points into template.  */
+  if (suffix_len && last_component (suffix) != suffix)
+    {
+      error (EXIT_FAILURE, 0,
+             _("invalid suffix %s, contains directory separator"),
+             quote (suffix));
+    }
+  x_count = count_consecutive_X_s (template, suffix - template);
   if (x_count < 3)
     error (EXIT_FAILURE, 0, _("too few X's in template %s"), quote (template));
 
@@ -242,11 +289,10 @@ main (int argc, char **argv)
                    quote (template));
         }
 
-      template = file_name_concat (dest_dir, template, NULL);
-    }
-  else
-    {
-      template = xstrdup (template);
+      dest_name = file_name_concat (dest_dir, template, NULL);
+      free (template);
+      template = dest_name;
+      /* Note that suffix is now invalid.  */
     }
 
   /* Make a copy to be used in case of diagnostic, since failing
@@ -255,7 +301,7 @@ main (int argc, char **argv)
 
   if (create_directory)
     {
-      int err = mkdtemp_len (dest_name, x_count, dry_run);
+      int err = mkdtemp_len (dest_name, suffix_len, x_count, dry_run);
       if (err != 0)
         {
           error (0, errno, _("failed to create directory via template %s"),
@@ -265,7 +311,7 @@ main (int argc, char **argv)
     }
   else
     {
-      int fd = mkstemp_len (dest_name, x_count, dry_run);
+      int fd = mkstemp_len (dest_name, suffix_len, x_count, dry_run);
       if (fd < 0 || (!dry_run && close (fd) != 0))
         {
           error (0, errno, _("failed to create file via template %s"),
diff --git a/tests/misc/mktemp b/tests/misc/mktemp
index e620311e9..7735f33d1 100755
--- a/tests/misc/mktemp
+++ b/tests/misc/mktemp
@@ -60,8 +60,8 @@ my @Tests =
        . "Try `$prog --help' for more information.\n"}, {EXIT => 1} ],
      ['too-many-q', '-q a b', {EXIT => 1} ],
 
-     ['too-few-x', 'foo.XX',
-      {ERR=>"$prog: too few X's in template `foo.XX'\n"}, {EXIT => 1} ],
+     ['too-few-x', 'foo.XX', {EXIT => 1},
+      {ERR=>"$prog: too few X's in template `foo.XX'\n"}],
      ['too-few-xq', '-q foo.XX', {EXIT => 1} ],
 
      ['1f', 'bar.XXXX', {OUT => "bar.ZZZZ\n"},
@@ -110,8 +110,72 @@ my @Tests =
        . "with --tmpdir, it may not be absolute\n"}, {EXIT => 1} ],
 
      # Suffix after X.
-     ['invalid-t3', 'aXXXXb',
-      {ERR=>"$prog: too few X's in template `aXXXXb'\n"}, {EXIT => 1} ],
+     ['suffix1f', 'aXXXXb', {OUT=>"aZZZZb\n"},
+      {OUT_SUBST=>'s,a....b,aZZZZb,'},
+      {POST => sub { my ($f) = @_; defined $f or return; chomp $f;
+       check_tmp $f, 'F'; }}],
+     ['suffix1d', '-d aXXXXb', {OUT=>"aZZZZb\n"},
+      {OUT_SUBST=>'s,a....b,aZZZZb,'},
+      {POST => sub { my ($f) = @_; defined $f or return; chomp $f;
+       check_tmp $f, 'D'; }}],
+     ['suffix1u', '-u aXXXXb', {OUT=>"aZZZZb\n"},
+      {OUT_SUBST=>'s,a....b,aZZZZb,'},
+      {POST => sub { my ($f) = @_; defined $f or return; chomp $f;
+       -e $f and die "dry-run created file"; }}],
+
+     ['suffix2f', 'aXXXXaaXXXXa', {OUT=>"aXXXXaaZZZZa\n"},
+      {OUT_SUBST=>'s,a....a$,aZZZZa,'},
+      {POST => sub { my ($f) = @_; defined $f or return; chomp $f;
+       check_tmp $f, 'F'; }}],
+     ['suffix2d', '-d --suffix= aXXXXaaXXXX', {OUT=>"aXXXXaaZZZZ\n"},
+      {OUT_SUBST=>'s,a....$,aZZZZ,'},
+      {POST => sub { my ($f) = @_; defined $f or return; chomp $f;
+       check_tmp $f, 'D'; }}],
+
+     ['suffix3f', '--suffix=b aXXXX', {OUT=>"aZZZZb\n"},
+      {OUT_SUBST=>'s,a....b,aZZZZb,'},
+      {POST => sub { my ($f) = @_; defined $f or return; chomp $f;
+       check_tmp $f, 'F'; }}],
+
+     ['suffix4f', '--suffix=X aXXXX', {OUT=>"aZZZZX\n"},
+      {OUT_SUBST=>'s,^a....,aZZZZ,'},
+      {POST => sub { my ($f) = @_; defined $f or return; chomp $f;
+       check_tmp $f, 'F'; }}],
+
+     ['suffix5f', '--suffix /b aXXXX', {EXIT=>1},
+      {ERR=>"$prog: invalid suffix `/b', contains directory separator\n"}],
+
+     ['suffix6f', 'aXXXX/b', {EXIT=>1},
+      {ERR=>"$prog: invalid suffix `/b', contains directory separator\n"}],
+     ['suffix6f-q', '-q aXXXX/b', {EXIT=>1}],
+
+     ['suffix7f', '--suffix= aXXXXb', {EXIT=>1},
+      {ERR=>"$prog: with --suffix, template `aXXXXb' must end in X\n"}],
+     ['suffix7f-q', '-q --suffix= aXXXXb', {EXIT=>1}],
+     ['suffix7d', '-d --suffix=aXXXXb ""', {EXIT=>1},
+      {ERR=>"$prog: with --suffix, template `' must end in X\n"}],
+
+     ['suffix8f', 'aXXXX --suffix=b', {OUT=>"aZZZZb\n"},
+      {OUT_SUBST=>'s,^a....,aZZZZ,'},
+      {POST => sub { my ($f) = @_; defined $f or return; chomp $f;
+       check_tmp $f, 'F'; }}],
+
+     ['suffix9f', 'aXXXX --suffix=b', {EXIT=>1},
+      {ENV=>"POSIXLY_CORRECT=1"},
+      {ERR=>"$prog: too many templates\n"
+       . "Try `$prog --help' for more information.\n"}],
+
+     ['suffix10f', 'aXXb', {EXIT => 1},
+      {ERR=>"$prog: too few X's in template `aXXb'\n"}],
+     ['suffix10d', '-d --suffix=X aXX', {EXIT => 1},
+      {ERR=>"$prog: too few X's in template `aXXX'\n"}],
+
+     ['suffix11f', '--suffix=.txt', {OUT=>"./tmp.ZZZZZZZZZZ.txt\n"},
+      {ENV=>"TMPDIR=."},
+      {OUT_SUBST=>'s,\..{10}\.,.ZZZZZZZZZZ.,'},
+      {POST => sub { my ($f) = @_; defined $f or return; chomp $f;
+       check_tmp $f, 'F'; }}],
+
 
      # Test template with subdirectory
      ['tmp-w-slash', '--tmpdir=. a/bXXXX',