Add better error reporting for conf file writing

sysmisc.c

@@ -215,8 +215,7 @@ FILE* conf_file_open_for_reading(void) {
 
 Conf_save_start_error conf_save_start(Conf_save* p) {
   memset(p, 0, sizeof(Conf_save));
-  oso *dir = NULL, *canonpath = NULL, *temppath = NULL;
-  FILE *origfile = NULL, *tempfile = NULL;
+  oso* dir = NULL;
   Conf_save_start_error err;
   if (try_get_conf_dir(&dir)) {
     err = Conf_save_start_no_home;
@@ -226,53 +225,54 @@ Conf_save_start_error conf_save_start(Conf_save* p) {
     err = Conf_save_start_alloc_failed;
     goto cleanup;
   }
-  osoputoso(&canonpath, dir);
-  osocat(&canonpath, conf_file_name);
-  if (!canonpath) {
+  osoputoso(&p->canonpath, dir);
+  osocat(&p->canonpath, conf_file_name);
+  if (!p->canonpath) {
     err = Conf_save_start_alloc_failed;
     goto cleanup;
   }
-  osoputoso(&temppath, canonpath);
-  osocat(&temppath, ".tmp");
-  if (!temppath) {
+  osoputoso(&p->temppath, p->canonpath);
+  osocat(&p->temppath, ".tmp");
+  if (!p->temppath) {
     err = Conf_save_start_alloc_failed;
     goto cleanup;
   }
   // Remove old temp file if it exists. If it exists and we can't remove it,
   // error.
-  if (unlink(osoc(temppath)) == -1 && errno != ENOENT) {
+  if (unlink(osoc(p->temppath)) == -1 && errno != ENOENT) {
+    switch (errno) {
+    case ENOTDIR:
+      err = Conf_save_start_conf_dir_not_dir;
+      break;
+    case EACCES:
+      err = Conf_save_start_temp_file_perm_denied;
+      break;
+    default:
       err = Conf_save_start_old_temp_file_stuck;
+      break;
+    }
     goto cleanup;
   }
-  tempfile = fopen(osoc(temppath), "w");
-  if (!tempfile) {
+  p->tempfile = fopen(osoc(p->temppath), "w");
+  if (!p->tempfile) {
     // Try to create config dir, in case it doesn't exist. (XDG says we should
     // do this, and use mode 0700.)
     mkdir(osoc(dir), 0700);
-    tempfile = fopen(osoc(temppath), "w");
+    p->tempfile = fopen(osoc(p->temppath), "w");
   }
-  if (!tempfile) {
+  if (!p->tempfile) {
     err = Conf_save_start_temp_file_open_failed;
     goto cleanup;
   }
   // This may be left as NULL.
-  origfile = fopen(osoc(canonpath), "r");
+  p->origfile = fopen(osoc(p->canonpath), "r");
   // We did it, boys.
   osofree(dir);
-  p->canonpath = canonpath;
-  p->temppath = temppath;
-  p->origfile = origfile;
-  p->tempfile = tempfile;
   return Conf_save_start_ok;
 
 cleanup:
   osofree(dir);
-  osofree(canonpath);
-  osofree(temppath);
-  if (origfile)
-    fclose(origfile);
-  if (tempfile)
-    fclose(tempfile);
+  conf_save_cancel(p);
   return err;
 }
 

sysmisc.h

@@ -40,6 +40,8 @@ typedef enum {
   Conf_save_start_alloc_failed,
   Conf_save_start_no_home,
   Conf_save_start_mkdir_failed,
+  Conf_save_start_conf_dir_not_dir,
+  Conf_save_start_temp_file_perm_denied,
   Conf_save_start_old_temp_file_stuck,
   Conf_save_start_temp_file_open_failed,
 } Conf_save_start_error;

tui_main.c

@@ -2393,17 +2393,42 @@ static void put_conf_pair(FILE* file, char const* left, char const* right) {
 
 typedef enum {
   Prefs_save_ok = 0,
-  Prefs_save_start_failed,
-  Prefs_save_commit_failed,
+  Prefs_save_oom,
+  Prefs_save_no_home,
+  Prefs_save_mkdir_failed,
+  Prefs_save_conf_dir_not_dir,
+  Prefs_save_old_temp_file_stuck,
+  Prefs_save_temp_file_perm_denied,
+  Prefs_save_temp_open_failed,
+  Prefs_save_temp_fsync_failed,
+  Prefs_save_temp_close_failed,
+  Prefs_save_rename_failed,
   Prefs_save_line_too_long,
   Prefs_save_existing_read_error,
+  Prefs_save_unknown_error,
 } Prefs_save_error;
 
 Prefs_save_error save_prefs_to_disk(Midi_mode const* midi_mode) {
   Conf_save save;
   Conf_save_start_error starterr = conf_save_start(&save);
-  if (starterr)
-    return Prefs_save_start_failed;
+  switch (starterr) {
+  case Conf_save_start_ok:
+    break;
+  case Conf_save_start_alloc_failed:
+    return Prefs_save_oom;
+  case Conf_save_start_no_home:
+    return Prefs_save_no_home;
+  case Conf_save_start_mkdir_failed:
+    return Prefs_save_mkdir_failed;
+  case Conf_save_start_conf_dir_not_dir:
+    return Prefs_save_conf_dir_not_dir;
+  case Conf_save_start_old_temp_file_stuck:
+    return Prefs_save_old_temp_file_stuck;
+  case Conf_save_start_temp_file_perm_denied:
+    return Prefs_save_temp_file_perm_denied;
+  case Conf_save_start_temp_file_open_failed:
+    return Prefs_save_temp_open_failed;
+  }
   bool need_cancel_save = true;
   enum Midi_output_pref {
     Midi_output_pref_none = 0,
@@ -2484,11 +2509,21 @@ done_reading_existing:
   }
   need_cancel_save = false;
   Conf_save_commit_error comerr = conf_save_commit(&save);
-  if (comerr) {
-    error = Prefs_save_commit_failed;
-    goto cleanup;
-  }
+  error = Prefs_save_unknown_error;
+  switch (comerr) {
+  case Conf_save_commit_ok:
     error = Prefs_save_ok;
+    break;
+  case Conf_save_commit_temp_fsync_failed:
+    error = Prefs_save_temp_fsync_failed;
+    break;
+  case Conf_save_commit_temp_close_failed:
+    error = Prefs_save_temp_close_failed;
+    break;
+  case Conf_save_commit_rename_failed:
+    error = Prefs_save_rename_failed;
+    break;
+  }
 cleanup:
   if (need_cancel_save)
     conf_save_cancel(&save);
@@ -2502,11 +2537,36 @@ void save_prefs_with_error_message(Midi_mode const* midi_mode) {
   switch (err) {
   case Prefs_save_ok:
     return;
-  case Prefs_save_start_failed:
-    msg = "Start failed";
+  case Prefs_save_oom:
+    msg = "Out of memory";
+    break;
+  case Prefs_save_no_home:
+    msg = "Unable to resolve $XDG_CONFIG_HOME or $HOME";
     break;
-  case Prefs_save_commit_failed:
-    msg = "Failed to commit save file";
+  case Prefs_save_mkdir_failed:
+    msg = "Unable to create $XDG_CONFIG_HOME or $HOME/.config directory";
+    break;
+  case Prefs_save_conf_dir_not_dir:
+    msg = "Config directory path is not a directory";
+    break;
+  case Prefs_save_old_temp_file_stuck:
+    msg = "Unable to remove old orca.conf.tmp file";
+    break;
+  case Prefs_save_temp_file_perm_denied:
+    msg = "Permission denied for config directory";
+    break;
+  case Prefs_save_temp_open_failed:
+    msg = "Unable to open orca.conf.tmp for writing";
+    break;
+  case Prefs_save_temp_fsync_failed:
+    msg = "fsync() reported an when writing temp file.\n"
+          "Refusing to continue.";
+    break;
+  case Prefs_save_temp_close_failed:
+    msg = "Unable to close temp file";
+    break;
+  case Prefs_save_rename_failed:
+    msg = "Unable to rename orca.conf.tmp to orca.conf";
     break;
   case Prefs_save_line_too_long:
     msg = "Line in file is too long";
@@ -2514,6 +2574,8 @@ void save_prefs_with_error_message(Midi_mode const* midi_mode) {
   case Prefs_save_existing_read_error:
     msg = "Error when reading existing configuration file";
     break;
+  case Prefs_save_unknown_error:
+    break;
   }
   qmsg_printf_push("Save Error", "Error when saving:\n%s", msg);
 }