con: support tab completion when both directories and files match

Fixes truncation warnings (caused by using strlcpy to copy an
unterminated substring, technically invoking UB with old strlcpy).
Closes https://gitlab.com/xonotic/darkplaces/-/issues/421

Signed-off-by: bones_was_here <bones_was_here@xonotic.au>

diff --git a/console.c b/console.c
index f46eddb5fb8bab5ce1863613f378dfab85eb24a6..2da2ddc53b2d81499ad4d3c76c872afb55af4377 100644 (file)
--- a/console.c
+++ b/console.c
@@ -2939,9 +2939,6 @@ int Con_CompleteCommandLine(cmd_state_t *cmd, qbool is_console)
                                //   set con_completion_playermodel "models/player/*.zym models/player/*.md3 models/player/*.psk models/player/*.dpm"
                                //   set con_completion_playdemo "*.dem"
                                //   set con_completion_play "*.wav *.ogg"
-                               //
-                               // TODO somehow add support for directories; these shall complete
-                               // to their name + an appended slash.
 
                                stringlistinit(&resultbuf);
                                stringlistinit(&dirbuf);
@@ -2957,7 +2954,7 @@ int Con_CompleteCommandLine(cmd_state_t *cmd, qbool is_console)
                                                const char *slash = strrchr(s, '/');
                                                if(slash)
                                                {
-                                                       dp_strlcpy(t, s, min(sizeof(t), (unsigned int)(slash - s + 2))); // + 2, because I want to include the slash
+                                                       dp_ustr2stp(t, sizeof(t), s, slash - s + 1); // + 1, because I want to include the slash
                                                        dp_strlcat(t, com_token, sizeof(t));
                                                        search = FS_Search(t, true, true, NULL);
                                                }
@@ -2980,7 +2977,7 @@ int Con_CompleteCommandLine(cmd_state_t *cmd, qbool is_console)
                                        const char *slash = strrchr(s, '/');
                                        if(slash)
                                        {
-                                               dp_strlcpy(t, s, min(sizeof(t), (unsigned int)(slash - s + 2))); // + 2, because I want to include the slash
+                                               dp_ustr2stp(t, sizeof(t), s, slash - s + 1); // + 1, because I want to include the slash
                                                dp_strlcat(t, "*", sizeof(t));
                                                search = FS_Search(t, true, true, NULL);
                                        }
@@ -3000,6 +2997,7 @@ int Con_CompleteCommandLine(cmd_state_t *cmd, qbool is_console)
                                {
                                        const char *p, *q;
                                        unsigned int matchchars;
+
                                        if(resultbuf.numstrings == 0 && dirbuf.numstrings == 1)
                                        {
                                                dpsnprintf(t, sizeof(t), "%s/", dirbuf.strings[0]);
@@ -3021,26 +3019,33 @@ int Con_CompleteCommandLine(cmd_state_t *cmd, qbool is_console)
                                                {
                                                        Con_Printf("%s\n", resultbuf.strings[i]);
                                                }
-                                               matchchars = sizeof(t) - 1;
-                                               if(resultbuf.numstrings > 0)
+
+                                               if(resultbuf.numstrings > 0) // matching file
                                                {
                                                        p = resultbuf.strings[0];
                                                        q = resultbuf.strings[resultbuf.numstrings - 1];
+                                                       if (dirbuf.numstrings > 0) // and matching directory
+                                                       {
+                                                               const char *r = dirbuf.strings[0];
+                                                               for(; *p && *p == *q && *p == *r; ++p, ++q, ++r);
+                                                       }
+                                                       else
                                                        for(; *p && *p == *q; ++p, ++q);
                                                        matchchars = (unsigned int)(p - resultbuf.strings[0]);
+                                                       dp_ustr2stp(t, sizeof(t), resultbuf.strings[0], matchchars);
                                                }
-                                               if(dirbuf.numstrings > 0)
+                                               else // matching directory only
                                                {
                                                        p = dirbuf.strings[0];
                                                        q = dirbuf.strings[dirbuf.numstrings - 1];
                                                        for(; *p && *p == *q; ++p, ++q);
-                                                       matchchars = min(matchchars, (unsigned int)(p - dirbuf.strings[0]));
+                                                       matchchars = (unsigned int)(p - dirbuf.strings[0]);
+                                                       dp_ustr2stp(t, sizeof(t), dirbuf.strings[0], matchchars);
                                                }
                                                // now p points to the first non-equal character, or to the end
                                                // of resultbuf.strings[0]. We want to append the characters
                                                // from resultbuf.strings[0] to (not including) p as these are
                                                // the unique prefix
-                                               dp_strlcpy(t, (resultbuf.numstrings > 0 ? resultbuf : dirbuf).strings[0], min(matchchars + 1, sizeof(t)));
                                        }
 
                                        // first move the cursor