c - gtk_file_chooser_dialog_new () 中的 g_slice_alloc () 出现段错误

Question

我正在 gtk+ 2.0 和 gtksourceview 2.0 中编写一个文本编辑器作为学习 C 的方式。当我尝试打开一个恰好位于 sshfs 上的文件时，我遇到了段错误。这并不总是一个问题，所以我不知道 sshfs 是否与此有关。

这是我的 open 函数中的一段代码:

  printf("\nentered open_activated\n");

  GtkSourceLanguage *lang;
  GtkSourceLanguageManager *lm;
  GtkWidget *dialog;
  GtkWidget *tablabel;
  GtkTextBuffer *tbuffer;
  int openTabs = 0;
  const gchar *folder;
  int page = 0;
  char *path,*string;

  page = gtk_notebook_get_current_page(GTK_NOTEBOOK(notebook));
  path  = paths[notebookPages[page]];
  folder = folderFromPath(path);
  printf("folder: %s\n\n",folder);

  dialog = gtk_file_chooser_dialog_new("Open File", parent, GTK_FILE_CHOOSER_ACTION_OPEN,GTK_STOCK_CANCEL,GTK_RESPONSE_CANCEL,GTK_STOCK_OPEN,GTK_RESPONSE_ACCEPT,NULL);
  gtk_file_chooser_set_current_folder (GTK_FILE_CHOOSER(dialog), folder);

其他信息

notebookPages 是一个全局整数数组:

#define NUM_TABS 100
int notebookPages[NUM_TABS];

paths 是一个全局字符数组:

char paths[NUM_TABS][200];

这是函数folderFromPath:

char * folderFromPath(char *path)
{
  printf("\nentered folderFromPath\n");

  char *token[80];
  int i = 0;  
  char str[80];
  strcpy(str,path);

    printf("path: %s\n", path);

  token[0] = strtok(str, "/");

  while (token[i]!= NULL)
  {
    i++;
    token[i] = strtok (NULL, "/");
  }

//   char folder[128];
    char *folder;
    folder = malloc(sizeof(path));

  if (folder != NULL)
  {
      int j = 0;
      strcpy(folder,"/");
      while (j < (i-1))
      {
              strcat(folder,token[j]);
              strcat(folder,"/");
          j++;
      }

      printf("folder: %s\n", folder);

    return folder;
      free(folder);
  }
  else
  {
    return "/";
  }
}

这是来自 gdb 的回溯:

#0  0xb6e1d257 in g_slice_alloc () from /usr/lib/libglib-2.0.so.0
#1  0xb6e1e42e in g_slist_prepend () from /usr/lib/libglib-2.0.so.0
#2  0xb6e27c74 in g_once_init_enter_impl () from /usr/lib/libglib-2.0.so.0
#3  0xb739e24e in gtk_dialog_get_type () from /usr/lib/libgtk-x11-2.0.so.0
#4  0xb73d1527 in gtk_file_chooser_dialog_get_type () from /usr/lib/libgtk-x11-2.0.so.0
#5  0xb73d15d6 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#6  0xb73d1735 in gtk_file_chooser_dialog_new () from /usr/lib/libgtk-x11-2.0.so.0
#7  0x08050506 in open_activated (widget=0x8266878, parent=0x8083a60) at ledit.c:1715
#8  0xb6eea3dc in g_cclosure_marshal_VOID__VOID () from /usr/lib/libgobject-2.0.so.0
#9  0xb6ee8f5a in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#10 0xb6efc816 in ?? () from /usr/lib/libgobject-2.0.so.0
#11 0xb6f05168 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#12 0xb6f05302 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#13 0xb755a3af in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#14 0xb6ee8f5a in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#15 0xb6efc816 in ?? () from /usr/lib/libgobject-2.0.so.0
#16 0xb6f04f13 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#17 0xb6f05302 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#18 0xb734aaa1 in gtk_accel_group_activate () from /usr/lib/libgtk-x11-2.0.so.0
#19 0xb734bf22 in gtk_accel_groups_activate () from /usr/lib/libgtk-x11-2.0.so.0
#20 0xb7575e7d in gtk_window_activate_key () from /usr/lib/libgtk-x11-2.0.so.0
#21 0xb7575eec in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#22 0xb7427b44 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#23 0xb6ee7a37 in ?? () from /usr/lib/libgobject-2.0.so.0
#24 0xb6ee8f5a in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#25 0xb6efc62c in ?? () from /usr/lib/libgobject-2.0.so.0
#26 0xb6f04f13 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#27 0xb6f05302 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#28 0xb755bbc6 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#29 0xb7425d63 in gtk_propagate_event () from /usr/lib/libgtk-x11-2.0.so.0
#30 0xb742608f in gtk_main_do_event () from /usr/lib/libgtk-x11-2.0.so.0
#31 0xb72aa42a in ?? () from /usr/lib/libgdk-x11-2.0.so.0
#32 0xb6dfed42 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#33 0xb6dff508 in ?? () from /usr/lib/libglib-2.0.so.0
#34 0xb6dffabb in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#35 0xb7424d59 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#36 0x0804d636 in main (argc=1, argv=0xbfad3774) at ledit.c:492

在我的学习过程中，我知道我确实需要了解更好的内存管理和指针。关于可能导致此段错误的原因有什么想法吗？或者关于如何进一步排除故障的任何想法？谢谢。

Answer 1

这行代码非常危险: strcpy(str,路径);

如果路径的长度大于str[]的长度，可能会导致写超出数组边界并其他不需要的结果。

请使用 strncpy 而不是 strcpy 或确保源字符串小于或等于目标字符串。