[tinfo] factor out do_terminfo_lookups()

src/lib/in.c

@@ -1478,6 +1478,76 @@ xtversion_cb(inputctx* ictx){
   return 2;
 }
 
+// precondition: s starts with two hex digits, the first of which is not
+// greater than 7.
+static inline char
+toxdigit(const char* s){
+  char c = isalpha(*s) ? tolower(*s) - 'a' + 10 : *s - '0';
+  c *= 16;
+  ++s;
+  c += isalpha(*s) ? tolower(*s) - 'a' + 10 : *s - '0';
+  return c;
+}
+
+// on success, the subsequent character is returned, and |key| and |val| have
+// heap-allocated, decoded, nul-terminated copies of the appropriate input.
+static const char*
+gettcap(const char* s, char** key, char** val){
+  const char* equals = s;
+  while(*equals != '='){
+    if(!isxdigit(*equals)){ // rejects a NUL byte
+      logerror("bad key in %s", s);
+      return NULL;
+    }
+    ++equals;
+  }
+  if(equals - s == 0 || (equals - s) % 2){
+    logerror("bad key in %s", s);
+    return NULL;
+  }
+  if((*key = malloc((equals - s) / 2 + 1)) == NULL){
+    return NULL;
+  }
+  char* keytarg = *key;
+  do{
+    *keytarg = toxdigit(s);
+    s += 2;
+    ++keytarg;
+  }while(*s != '=');
+  *keytarg = '\0';
+  ++equals; // now one past the equal sign
+  const char *end = equals;
+  while(*end != ';' && *end){
+    if(!isxdigit(*end)){
+      logerror("bad value in %s", s);
+      goto valerr;
+    }
+    ++end;
+  }
+  if(end - equals == 0 || (end - equals) % 2){
+    logerror("bad value in %s", s);
+    goto valerr;
+  }
+  if((*val = malloc((end - equals) / 2 + 1)) == NULL){
+    goto valerr;
+  }
+  char* valtarg = *val;
+  ++s;
+  do{
+    *valtarg = toxdigit(s);
+    s += 2;
+    ++valtarg;
+  }while(s != end);
+  *valtarg = '\0';
+  loginfo("key: %s val: %s", *key, *val);
+  return end;
+
+valerr:
+  free(*key);
+  *key = NULL;
+  return end;
+}
+
 // XTGETTCAP responses are delimited by semicolons
 static int
 tcap_cb(inputctx* ictx){
@@ -1490,47 +1560,41 @@ tcap_cb(inputctx* ictx){
     free(str);
     return 2;
   }
-  char* s = str;
-  while(*s){
-    // FIXME clean this crap up, grotesque
-    if(strncasecmp(s, "544e=", 5) == 0){
-      size_t len = 5;
-      while(s[len] && s[len] != ';'){
-        ++len;
-      }
-      const char* tn = s + 5;
-      len -= 5;
+  const char* s = str;
+  char* key;
+  char* val;
+  // answers are delimited with semicolons, hex-encoded, key=value
+  while(*s && (s = gettcap(s, &val, &key)) ){
+    if(strcmp(val, "TN") == 0){
       if(ictx->initdata->qterm == TERMINAL_UNKNOWN){
-        if(len == 10){
-          if(strncasecmp(tn, "787465726d", 10) == 0){
-            ictx->initdata->qterm = TERMINAL_XTERM; // "xterm"
-          }
-        }else if(len == 12){
-          if(strncasecmp(tn, "6D6C7465726D", 12) == 0){
-            ictx->initdata->qterm = TERMINAL_MLTERM;
-          }
-        }else if(len == 22){
-          if(strncasecmp(tn, "787465726d2d6b69747479", 22) == 0){
-            ictx->initdata->qterm = TERMINAL_KITTY; // "xterm-kitty"
-          }
-        }else if(len == 28){
-          if(strncasecmp(tn, "787465726d2d323536636f6c6f72", 28) == 0){
-            ictx->initdata->qterm = TERMINAL_XTERM; // "xterm-256color"
-          }
+        if(strcasecmp(key, "xterm") == 0){
+          ictx->initdata->qterm = TERMINAL_XTERM; // "xterm"
+        }else if(strcasecmp(key, "mlterm") == 0){
+          ictx->initdata->qterm = TERMINAL_MLTERM;
+        }else if(strcasecmp(key, "xterm-kitty") == 0){
+          ictx->initdata->qterm = TERMINAL_KITTY; // "xterm-kitty"
+        }else if(strcasecmp(key, "xterm-256color") == 0){
+          ictx->initdata->qterm = TERMINAL_XTERM; // "xterm-256color"
         }else{
-          logdebug("unknown terminal name %s", tn);
+          logdebug("unknown terminal name %s", key);
         }
       }
-    }else if(strncasecmp(s, "524742=", 7) == 0){
+    }else if(strcmp(val, "RGB") == 0){
       loginfo("got rgb (%s)", s);
       ictx->initdata->rgb = true;
+    }else if(strcmp(val, "hpa") == 0){
+      loginfo("got hpa (%s)", key);
+      ictx->initdata->hpa = key;
+      key = NULL;
     }else{
-      logdebug("unknown capability=val %s", str);
+      logwarn("unknown capability: %s", str);
     }
-    if((s = strchr(s, ';')) == NULL){
-      break;
-    }
-    ++s;
+    free(val);
+    free(key);
+  }
+  if(*s){
+    free(str);
+    return -1;
   }
   free(str);
   return 2;

src/lib/in.h

@@ -82,6 +82,7 @@ struct initial_responses {
   ncpalette palette;           // palette entries
   int maxpaletteread;          // maximum palette index read
   bool pixelmice;              // have we pixel-based mice events?
+  char* hpa;                   // control sequence for hpa via XTGETTCAP
 };
 
 // Blocking call. Waits until the input thread has processed all responses to

src/lib/logging.h

@@ -8,6 +8,9 @@ extern "C" {
 // logging
 extern ncloglevel_e loglevel;
 
+static inline void nclog(const char* fmt, ...)
+__attribute__ ((format (printf, 1, 2)));
+
 static inline void
 nclog(const char* fmt, ...){
   va_list va;

src/lib/termdesc.c

@@ -455,8 +455,15 @@ init_terminfo_esc(tinfo* ti, const char* name, escape_e idx,
 // XTVERSION. Replies with DCS > | ... ST
 #define XTVERSION "\x1b[>0q"
 
-// XTGETTCAP['TN', 'RGB'] (Terminal Name, RGB)
-#define XTGETTCAP  "\x1bP+q544e;524742\x1b\\"
+// ideally we'd abandon terminfo entirely (terminfo is great; TERM sucks), and
+// get all properties through terminal queries. we don't yet, but grab a few
+// of importance that we know to oftentimes be incorrect:
+//  * TN (544e): terminal name; a poor man's XTVERSION
+//  * RGB (524742): 24-bit color is supported via setaf/setab
+//  * hpa (687061): broken in Kitty FreeBSD terminfo (#2541)
+// XTGETTCAP['TN', 'RGB', 'hpa']
+// (Terminal Name, RGB, Horizontal Position Absolute)
+#define XTGETTCAP  "\x1bP+q544e;524742;687061\x1b\\"
 
 // Secondary Device Attributes, necessary to get Alacritty's version. Since
 // this doesn't uniquely identify a terminal, we ask it last, so that if any
@@ -1052,6 +1059,60 @@ unix_early_matches(const char* term){
 #endif
 #endif
 
+static int
+do_terminfo_lookups(tinfo *ti, size_t* tablelen, size_t* tableused){
+  // don't list any here for which we also send XTGETTCAP sequences
+  const struct strtdesc {
+    escape_e esc;
+    const char* tinfo;
+  } strtdescs[] = {
+    { ESCAPE_CUP, "cup", },
+    { ESCAPE_HPA, "hpa", },
+    { ESCAPE_VPA, "vpa", },
+    // Not all terminals support setting the fore/background independently
+    { ESCAPE_SETAF, "setaf", },
+    { ESCAPE_SETAB, "setab", },
+    { ESCAPE_OP, "op", },
+    { ESCAPE_CNORM, "cnorm", },
+    { ESCAPE_CIVIS, "civis", },
+    { ESCAPE_SGR0, "sgr0", },
+    { ESCAPE_SITM, "sitm", },
+    { ESCAPE_RITM, "ritm", },
+    { ESCAPE_BOLD, "bold", },
+    { ESCAPE_CUD, "cud", },
+    { ESCAPE_CUU, "cuu", },
+    { ESCAPE_CUF, "cuf", },
+    { ESCAPE_CUB, "cub", },
+    { ESCAPE_U7, "u7", },
+    { ESCAPE_SMKX, "smkx", },
+    { ESCAPE_SMXX, "smxx", },
+    { ESCAPE_EL, "el", },
+    { ESCAPE_RMXX, "rmxx", },
+    { ESCAPE_SMUL, "smul", },
+    { ESCAPE_RMUL, "rmul", },
+    { ESCAPE_SC, "sc", },
+    { ESCAPE_RC, "rc", },
+    { ESCAPE_IND, "ind", },
+    { ESCAPE_INDN, "indn", },
+    { ESCAPE_CLEAR, "clear", },
+    { ESCAPE_OC, "oc", },
+    { ESCAPE_RMKX, "rmkx", },
+    { ESCAPE_INITC, "initc", },
+    { ESCAPE_MAX, NULL, },
+  };
+  for(typeof(*strtdescs)* strtdesc = strtdescs ; strtdesc->esc < ESCAPE_MAX ; ++strtdesc){
+    if(init_terminfo_esc(ti, strtdesc->tinfo, strtdesc->esc, tablelen, tableused)){
+      return -1;
+    }
+  }
+  // verify that the terminal provides cursor addressing (absolute movement)
+  if(ti->escindices[ESCAPE_CUP] == 0){
+    logpanic("required terminfo capability 'cup' not defined");
+    return -1;
+  }
+  return 0;
+}
+
 // if |termtype| is not NULL, it is used to look up the terminfo database entry
 // via setupterm(). the value of the TERM environment variable is otherwise
 // (implicitly) used. some details are not exposed via terminfo, and we must
@@ -1167,52 +1228,7 @@ int interrogate_terminfo(tinfo* ti, FILE* out, unsigned utf8,
     }
     ti->caps.rgb = query_rgb(); // independent of colors
   }
-  const struct strtdesc {
-    escape_e esc;
-    const char* tinfo;
-  } strtdescs[] = {
-    { ESCAPE_CUP, "cup", },
-    { ESCAPE_HPA, "hpa", },
-    { ESCAPE_VPA, "vpa", },
-    // Not all terminals support setting the fore/background independently
-    { ESCAPE_SETAF, "setaf", },
-    { ESCAPE_SETAB, "setab", },
-    { ESCAPE_OP, "op", },
-    { ESCAPE_CNORM, "cnorm", },
-    { ESCAPE_CIVIS, "civis", },
-    { ESCAPE_SGR0, "sgr0", },
-    { ESCAPE_SITM, "sitm", },
-    { ESCAPE_RITM, "ritm", },
-    { ESCAPE_BOLD, "bold", },
-    { ESCAPE_CUD, "cud", },
-    { ESCAPE_CUU, "cuu", },
-    { ESCAPE_CUF, "cuf", },
-    { ESCAPE_CUB, "cub", },
-    { ESCAPE_U7, "u7", },
-    { ESCAPE_SMKX, "smkx", },
-    { ESCAPE_SMXX, "smxx", },
-    { ESCAPE_EL, "el", },
-    { ESCAPE_RMXX, "rmxx", },
-    { ESCAPE_SMUL, "smul", },
-    { ESCAPE_RMUL, "rmul", },
-    { ESCAPE_SC, "sc", },
-    { ESCAPE_RC, "rc", },
-    { ESCAPE_IND, "ind", },
-    { ESCAPE_INDN, "indn", },
-    { ESCAPE_CLEAR, "clear", },
-    { ESCAPE_OC, "oc", },
-    { ESCAPE_RMKX, "rmkx", },
-    { ESCAPE_INITC, "initc", },
-    { ESCAPE_MAX, NULL, },
-  };
-  for(typeof(*strtdescs)* strtdesc = strtdescs ; strtdesc->esc < ESCAPE_MAX ; ++strtdesc){
-    if(init_terminfo_esc(ti, strtdesc->tinfo, strtdesc->esc, &tablelen, &tableused)){
-      goto err;
-    }
-  }
-  // verify that the terminal provides cursor addressing (absolute movement)
-  if(ti->escindices[ESCAPE_CUP] == 0){
-    logpanic("required terminfo capability 'cup' not defined");
+  if(do_terminfo_lookups(ti, &tablelen, &tableused)){
     goto err;
   }
   if(ti->ttyfd >= 0){