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, 38 insertions, 36 deletions

diff --git a/src/tail.c b/src/tail.c
index 6c5dd3a9d..223c8f839 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -360,7 +360,7 @@ close_fd (int fd, const char *filename)
 {
   if (fd != -1 && fd != STDIN_FILENO && close (fd))
     {
-      error (0, errno, _("closing %s (fd=%d)"), quote (filename), fd);
+      error (0, errno, _("closing %s (fd=%d)"), quoteaf (filename), fd);
     }
 }
 
@@ -383,7 +383,7 @@ xwrite_stdout (char const *buffer, size_t n_bytes)
     {
       clearerr (stdout); /* To avoid redundant close_stdout diagnostic.  */
       error (EXIT_FAILURE, errno, _("error writing %s"),
-             quote ("standard output"));
+             quoteaf ("standard output"));
     }
 }
 
@@ -408,7 +408,7 @@ dump_remainder (const char *pretty_filename, int fd, uintmax_t n_bytes)
         {
           if (errno != EAGAIN)
             error (EXIT_FAILURE, errno, _("error reading %s"),
-                   quote (pretty_filename));
+                   quoteaf (pretty_filename));
           break;
         }
       if (bytes_read == 0)
@@ -446,15 +446,15 @@ xlseek (int fd, off_t offset, int whence, char const *filename)
     {
     case SEEK_SET:
       error (0, errno, _("%s: cannot seek to offset %s"),
-             quote (filename), s);
+             quotef (filename), s);
       break;
     case SEEK_CUR:
       error (0, errno, _("%s: cannot seek to relative offset %s"),
-             quote (filename), s);
+             quotef (filename), s);
       break;
     case SEEK_END:
       error (0, errno, _("%s: cannot seek to end-relative offset %s"),
-             quote (filename), s);
+             quotef (filename), s);
       break;
     default:
       abort ();
@@ -495,7 +495,7 @@ file_lines (const char *pretty_filename, int fd, uintmax_t n_lines,
   bytes_read = safe_read (fd, buffer, bytes_read);
   if (bytes_read == SAFE_READ_ERROR)
     {
-      error (0, errno, _("error reading %s"), quote (pretty_filename));
+      error (0, errno, _("error reading %s"), quoteaf (pretty_filename));
       return false;
     }
   *read_pos = pos + bytes_read;
@@ -544,7 +544,7 @@ file_lines (const char *pretty_filename, int fd, uintmax_t n_lines,
       bytes_read = safe_read (fd, buffer, BUFSIZ);
       if (bytes_read == SAFE_READ_ERROR)
         {
-          error (0, errno, _("error reading %s"), quote (pretty_filename));
+          error (0, errno, _("error reading %s"), quoteaf (pretty_filename));
           return false;
         }
 
@@ -637,7 +637,7 @@ pipe_lines (const char *pretty_filename, int fd, uintmax_t n_lines,
 
   if (n_read == SAFE_READ_ERROR)
     {
-      error (0, errno, _("error reading %s"), quote (pretty_filename));
+      error (0, errno, _("error reading %s"), quoteaf (pretty_filename));
       ok = false;
       goto free_lbuffers;
     }
@@ -765,7 +765,7 @@ pipe_bytes (const char *pretty_filename, int fd, uintmax_t n_bytes,
 
   if (n_read == SAFE_READ_ERROR)
     {
-      error (0, errno, _("error reading %s"), quote (pretty_filename));
+      error (0, errno, _("error reading %s"), quoteaf (pretty_filename));
       ok = false;
       goto free_cbuffers;
     }
@@ -813,7 +813,7 @@ start_bytes (const char *pretty_filename, int fd, uintmax_t n_bytes,
         return -1;
       if (bytes_read == SAFE_READ_ERROR)
         {
-          error (0, errno, _("error reading %s"), quote (pretty_filename));
+          error (0, errno, _("error reading %s"), quoteaf (pretty_filename));
           return 1;
         }
       *read_pos += bytes_read;
@@ -850,7 +850,7 @@ start_lines (const char *pretty_filename, int fd, uintmax_t n_lines,
         return -1;
       if (bytes_read == SAFE_READ_ERROR) /* error */
         {
-          error (0, errno, _("error reading %s"), quote (pretty_filename));
+          error (0, errno, _("error reading %s"), quoteaf (pretty_filename));
           return 1;
         }
 
@@ -891,7 +891,7 @@ fremote (int fd, const char *name)
          is open on a pipe.  Treat that like a remote file.  */
       if (errno != ENOSYS)
         error (0, errno, _("cannot determine location of %s. "
-                           "reverting to polling"), quote (name));
+                           "reverting to polling"), quoteaf (name));
     }
   else
     {
@@ -952,7 +952,7 @@ recheck (struct File_spec *f, bool blocking)
       f->ignore = true;
 
       error (0, 0, _("%s has been replaced with a symbolic link. "
-                     "giving up on this name"), quote (pretty_name (f)));
+                     "giving up on this name"), quoteaf (pretty_name (f)));
     }
   else if (fd == -1 || fstat (fd, &new_stats) < 0)
     {
@@ -967,7 +967,7 @@ recheck (struct File_spec *f, bool blocking)
                  be seen to be the same file (dev/ino).  Otherwise, tail prints
                  the entire contents of the file when it becomes readable.  */
               error (0, f->errnum, _("%s has become inaccessible"),
-                     quote (pretty_name (f)));
+                     quoteaf (pretty_name (f)));
             }
           else
             {
@@ -975,7 +975,7 @@ recheck (struct File_spec *f, bool blocking)
             }
         }
       else if (prev_errnum != errno)
-        error (0, errno, "%s", quote (pretty_name (f)));
+        error (0, errno, "%s", quotef (pretty_name (f)));
     }
   else if (!IS_TAILABLE_FILE_TYPE (new_stats.st_mode))
     {
@@ -983,7 +983,7 @@ recheck (struct File_spec *f, bool blocking)
       f->errnum = -1;
       error (0, 0, _("%s has been replaced with an untailable file;\
  giving up on this name"),
-             quote (pretty_name (f)));
+             quoteaf (pretty_name (f)));
       f->ignore = true;
     }
   else if (!disable_inotify && fremote (fd, pretty_name (f)))
@@ -991,7 +991,7 @@ recheck (struct File_spec *f, bool blocking)
       ok = false;
       f->errnum = -1;
       error (0, 0, _("%s has been replaced with a remote file. "
-                     "giving up on this name"), quote (pretty_name (f)));
+                     "giving up on this name"), quoteaf (pretty_name (f)));
       f->ignore = true;
       f->remote = true;
     }
@@ -1011,7 +1011,7 @@ recheck (struct File_spec *f, bool blocking)
     {
       new_file = true;
       assert (f->fd == -1);
-      error (0, 0, _("%s has become accessible"), quote (pretty_name (f)));
+      error (0, 0, _("%s has become accessible"), quoteaf (pretty_name (f)));
     }
   else if (f->fd == -1)
     {
@@ -1024,7 +1024,7 @@ recheck (struct File_spec *f, bool blocking)
 
       error (0, 0,
              _("%s has appeared;  following new file"),
-             quote (pretty_name (f)));
+             quoteaf (pretty_name (f)));
     }
   else if (f->ino != new_stats.st_ino || f->dev != new_stats.st_dev)
     {
@@ -1034,7 +1034,7 @@ recheck (struct File_spec *f, bool blocking)
 
       error (0, 0,
              _("%s has been replaced;  following new file"),
-             quote (pretty_name (f)));
+             quoteaf (pretty_name (f)));
 
       /* Close the old one.  */
       close_fd (f->fd, pretty_name (f));
@@ -1151,7 +1151,7 @@ tail_forever (struct File_spec *f, size_t n_files, double sleep_interval)
                   else
                     error (EXIT_FAILURE, errno,
                            _("%s: cannot change nonblocking mode"),
-                           quote (name));
+                           quotef (name));
                 }
               else
                 f[i].blocking = blocking;
@@ -1163,7 +1163,7 @@ tail_forever (struct File_spec *f, size_t n_files, double sleep_interval)
                 {
                   f[i].fd = -1;
                   f[i].errnum = errno;
-                  error (0, errno, "%s", quote (name));
+                  error (0, errno, "%s", quotef (name));
                   close (fd); /* ignore failure */
                   continue;
                 }
@@ -1196,7 +1196,7 @@ tail_forever (struct File_spec *f, size_t n_files, double sleep_interval)
                  (in which case we ignore new data <= size).  */
               if (S_ISREG (mode) && stats.st_size < f[i].size)
                 {
-                  error (0, 0, _("%s: file truncated"), quote (name));
+                  error (0, 0, _("%s: file truncated"), quotef (name));
                   /* Assume the file was truncated to 0,
                      and therefore output all "new" data.  */
                   xlseek (fd, 0, SEEK_SET, name);
@@ -1338,7 +1338,7 @@ check_fspec (struct File_spec *fspec, struct File_spec **prev_fspec)
      separate events for truncate() and write().  */
   if (S_ISREG (fspec->mode) && stats.st_size < fspec->size)
     {
-      error (0, 0, _("%s: file truncated"), quote (name));
+      error (0, 0, _("%s: file truncated"), quotef (name));
       xlseek (fspec->fd, 0, SEEK_SET, name);
       fspec->size = 0;
     }
@@ -1433,7 +1433,7 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files,
                 {
                   if (errno != ENOSPC) /* suppress confusing error.  */
                     error (0, errno, _("cannot watch parent directory of %s"),
-                           quote (f[i].name));
+                           quoteaf (f[i].name));
                   else
                     error (0, 0, _("inotify resources exhausted"));
                   found_unwatchable_dir = true;
@@ -1456,7 +1456,7 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files,
                   break;
                 }
               else if (errno != f[i].errnum)
-                error (0, errno, _("cannot watch %s"), quote (f[i].name));
+                error (0, errno, _("cannot watch %s"), quoteaf (f[i].name));
               continue;
             }
 
@@ -1506,7 +1506,7 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files,
                   && (f[i].dev != stats.st_dev || f[i].ino != stats.st_ino))
                 {
                   error (0, errno, _("%s was replaced"),
-                         quote (pretty_name (&(f[i]))));
+                         quoteaf (pretty_name (&(f[i]))));
                   hash_free (wd_to_name);
 
                   errno = 0;
@@ -1635,7 +1635,7 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files,
               else
                 {
                   /* Can get ENOENT for a dangling symlink for example.  */
-                  error (0, errno, _("cannot watch %s"), quote (f[j].name));
+                  error (0, errno, _("cannot watch %s"), quoteaf (f[j].name));
                 }
               /* We'll continue below after removing the existing watch.  */
             }
@@ -1726,7 +1726,7 @@ tail_bytes (const char *pretty_filename, int fd, uintmax_t n_bytes,
 
   if (fstat (fd, &stats))
     {
-      error (0, errno, _("cannot fstat %s"), quote (pretty_filename));
+      error (0, errno, _("cannot fstat %s"), quoteaf (pretty_filename));
       return false;
     }
 
@@ -1782,7 +1782,7 @@ tail_lines (const char *pretty_filename, int fd, uintmax_t n_lines,
 
   if (fstat (fd, &stats))
     {
-      error (0, errno, _("cannot fstat %s"), quote (pretty_filename));
+      error (0, errno, _("cannot fstat %s"), quoteaf (pretty_filename));
       return false;
     }
 
@@ -1881,7 +1881,7 @@ tail_file (struct File_spec *f, uintmax_t n_units)
           f->dev = 0;
         }
       error (0, errno, _("cannot open %s for reading"),
-             quote (pretty_name (f)));
+             quoteaf (pretty_name (f)));
       ok = false;
     }
   else
@@ -1906,13 +1906,14 @@ tail_file (struct File_spec *f, uintmax_t n_units)
             {
               ok = false;
               f->errnum = errno;
-              error (0, errno, _("error reading %s"), quote (pretty_name (f)));
+              error (0, errno, _("error reading %s"),
+                     quoteaf (pretty_name (f)));
             }
           else if (!IS_TAILABLE_FILE_TYPE (stats.st_mode))
             {
               error (0, 0, _("%s: cannot follow end of this type of file;\
  giving up on this name"),
-                     quote (pretty_name (f)));
+                     quotef (pretty_name (f)));
               ok = false;
               f->errnum = -1;
               f->ignore = true;
@@ -1936,7 +1937,8 @@ tail_file (struct File_spec *f, uintmax_t n_units)
         {
           if (!is_stdin && close (fd))
             {
-              error (0, errno, _("error reading %s"), quote (pretty_name (f)));
+              error (0, errno, _("error reading %s"),
+                     quoteaf (pretty_name (f)));
               ok = false;
             }
         }
@@ -2258,7 +2260,7 @@ main (int argc, char **argv)
 
     /* When following by name, there must be a name.  */
     if (found_hyphen && follow_mode == Follow_name)
-      error (EXIT_FAILURE, 0, _("cannot follow %s by name"), quote ("-"));
+      error (EXIT_FAILURE, 0, _("cannot follow %s by name"), quoteaf ("-"));
 
     /* When following forever, warn if any file is '-'.
        This is only a warning, since tail's output (before a failing seek,