all: avoid quoting file names when possible

Quote file names using the "shell-escape" or "shell-escape-always"
methods, which quote as appropriate for most shells,
and better support copy and paste of presented names.
The "always" variant is used when the file name is
embedded in an error message with surrounding spaces.

* cfg.mk (sc_error_shell_quotes): A new syntax check rule
to suggest quotef() where appropriate.
(sc_error_shell_always_quotes): Likewise for quoteaf().
* src/system.h (quotef): A new define to apply shell quoting
when needed.  I.E. when shell character or ':' is present.
(quoteaf): Likewise, but always quote.
* src/*.c: Use quotef() and quoteaf() rather than quote()
where appropriate.
* tests/: Adjust accordingly.

1 files changed, 23 insertions, 22 deletions

diff --git a/src/ln.c b/src/ln.c
index 652103b15..974a9f0e4 100644
--- a/src/ln.c
+++ b/src/ln.c
@@ -28,7 +28,6 @@
 #include "file-set.h"
 #include "hash.h"
 #include "hash-triple.h"
-#include "quote.h"
 #include "relpath.h"
 #include "same.h"
 #include "yesno.h"
@@ -130,9 +129,10 @@ target_directory_operand (char const *file)
   int err = (stat_result == 0 ? 0 : errno);
   bool is_a_dir = !err && S_ISDIR (st.st_mode);
   if (err && ! errno_nonexisting (errno))
-    error (EXIT_FAILURE, err, _("failed to access %s"), quote (file));
+    error (EXIT_FAILURE, err, _("failed to access %s"), quoteaf (file));
   if (is_a_dir < looks_like_a_dir)
-    error (EXIT_FAILURE, err, _("target %s is not a directory"), quote (file));
+    error (EXIT_FAILURE, err, _("target %s is not a directory"),
+           quoteaf (file));
   return is_a_dir;
 }
 
@@ -194,7 +194,7 @@ do_link (const char *source, const char *dest)
            : lstat (source, &source_stats))
           != 0)
         {
-          error (0, errno, _("failed to access %s"), quote (source));
+          error (0, errno, _("failed to access %s"), quoteaf (source));
           return false;
         }
 
@@ -204,7 +204,7 @@ do_link (const char *source, const char *dest)
           if (! hard_dir_link)
             {
               error (0, 0, _("%s: hard link not allowed for directory"),
-                     quote (source));
+                     quotef (source));
               return false;
             }
         }
@@ -215,7 +215,7 @@ do_link (const char *source, const char *dest)
       dest_lstat_ok = (lstat (dest, &dest_stats) == 0);
       if (!dest_lstat_ok && errno != ENOENT)
         {
-          error (0, errno, _("failed to access %s"), quote (dest));
+          error (0, errno, _("failed to access %s"), quoteaf (dest));
           return false;
         }
     }
@@ -228,7 +228,7 @@ do_link (const char *source, const char *dest)
     {
       error (0, 0,
              _("will not overwrite just-created %s with %s"),
-             quote_n (0, dest), quote_n (1, source));
+             quoteaf_n (0, dest), quoteaf_n (1, source));
       return false;
     }
 
@@ -260,7 +260,7 @@ do_link (const char *source, const char *dest)
       && (source_stats.st_nlink == 1 || same_name (source, dest)))
     {
       error (0, 0, _("%s and %s are the same file"),
-             quote_n (0, source), quote_n (1, dest));
+             quoteaf_n (0, source), quoteaf_n (1, dest));
       return false;
     }
 
@@ -268,12 +268,12 @@ do_link (const char *source, const char *dest)
     {
       if (S_ISDIR (dest_stats.st_mode))
         {
-          error (0, 0, _("%s: cannot overwrite directory"), quote (dest));
+          error (0, 0, _("%s: cannot overwrite directory"), quotef (dest));
           return false;
         }
       if (interactive)
         {
-          fprintf (stderr, _("%s: replace %s? "), program_name, quote (dest));
+          fprintf (stderr, _("%s: replace %s? "), program_name, quoteaf (dest));
           if (!yesno ())
             return true;
           remove_existing_files = true;
@@ -289,7 +289,8 @@ do_link (const char *source, const char *dest)
               dest_backup = NULL;
               if (rename_errno != ENOENT)
                 {
-                  error (0, rename_errno, _("cannot backup %s"), quote (dest));
+                  error (0, rename_errno, _("cannot backup %s"),
+                         quoteaf (dest));
                   return false;
                 }
             }
@@ -327,7 +328,7 @@ do_link (const char *source, const char *dest)
     {
       if (unlink (dest) != 0)
         {
-          error (0, errno, _("cannot remove %s"), quote (dest));
+          error (0, errno, _("cannot remove %s"), quoteaf (dest));
           free (dest_backup);
           free (rel_source);
           return false;
@@ -349,9 +350,9 @@ do_link (const char *source, const char *dest)
       if (verbose)
         {
           if (dest_backup)
-            printf ("%s ~ ", quote (dest_backup));
-          printf ("%s %c> %s\n", quote_n (0, dest), (symbolic_link ? '-' : '='),
-                  quote_n (1, source));
+            printf ("%s ~ ", quoteaf (dest_backup));
+          printf ("%s %c> %s\n", quoteaf_n (0, dest),
+                  (symbolic_link ? '-' : '='), quoteaf_n (1, source));
         }
     }
   else
@@ -367,12 +368,12 @@ do_link (const char *source, const char *dest)
                     || errno == EROFS)
                  ? _("failed to create hard link %s")
                  : _("failed to create hard link %s => %s"))),
-             quote_n (0, dest), quote_n (1, source));
+             quoteaf_n (0, dest), quoteaf_n (1, source));
 
       if (dest_backup)
         {
           if (rename (dest_backup, dest) != 0)
-            error (0, errno, _("cannot un-backup %s"), quote (dest));
+            error (0, errno, _("cannot un-backup %s"), quoteaf (dest));
         }
     }
 
@@ -530,10 +531,10 @@ main (int argc, char **argv)
               struct stat st;
               if (stat (optarg, &st) != 0)
                 error (EXIT_FAILURE, errno, _("failed to access %s"),
-                       quote (optarg));
+                       quoteaf (optarg));
               if (! S_ISDIR (st.st_mode))
                 error (EXIT_FAILURE, 0, _("target %s is not a directory"),
-                       quote (optarg));
+                       quoteaf (optarg));
             }
           target_directory = optarg;
           break;
@@ -575,9 +576,9 @@ main (int argc, char **argv)
           if (n_files < 2)
             error (0, 0,
                    _("missing destination file operand after %s"),
-                   quote (file[0]));
+                   quoteaf (file[0]));
           else
-            error (0, 0, _("extra operand %s"), quote (file[2]));
+            error (0, 0, _("extra operand %s"), quoteaf (file[2]));
           usage (EXIT_FAILURE);
         }
     }
@@ -589,7 +590,7 @@ main (int argc, char **argv)
         target_directory = file[--n_files];
       else if (2 < n_files)
         error (EXIT_FAILURE, 0, _("target %s is not a directory"),
-               quote (file[n_files - 1]));
+               quoteaf (file[n_files - 1]));
     }
 
   if (backup_suffix_string)