osutil: fix some braindamage

- entkind returns -1 on failure
- compile if AT_SYMLINK_NOFOLLOW is missing
- avoid fullpath overflow

mercurial/osutil.c

@@ -1,226 +1,225
 /*
  osutil.c - native operating system services
 
  Copyright 2007 Matt Mackall and others
 
  This software may be used and distributed according to the terms of
  the GNU General Public License, incorporated herein by reference.
 */
 
 #define _ATFILE_SOURCE
 #include <Python.h>
 #include <dirent.h>
 #include <fcntl.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 struct listdir_stat {
 	PyObject_HEAD
 	struct stat st;
 };
 
 #define listdir_slot(name) \
     static PyObject *listdir_stat_##name(PyObject *self, void *x) \
     { \
         return PyInt_FromLong(((struct listdir_stat *)self)->st.name); \
     }
 
 listdir_slot(st_dev)
 listdir_slot(st_mode)
 listdir_slot(st_nlink)
 listdir_slot(st_size)
 listdir_slot(st_mtime)
 listdir_slot(st_ctime)
 
 static struct PyGetSetDef listdir_stat_getsets[] = {
 	{"st_dev", listdir_stat_st_dev, 0, 0, 0},
 	{"st_mode", listdir_stat_st_mode, 0, 0, 0},
 	{"st_nlink", listdir_stat_st_nlink, 0, 0, 0},
 	{"st_size", listdir_stat_st_size, 0, 0, 0},
 	{"st_mtime", listdir_stat_st_mtime, 0, 0, 0},
 	{"st_ctime", listdir_stat_st_ctime, 0, 0, 0},
 	{0, 0, 0, 0, 0}
 };
 
 static PyObject *listdir_stat_new(PyTypeObject *t, PyObject *a, PyObject *k)
 {
 	return t->tp_alloc(t, 0);
 }
 
 static void listdir_stat_dealloc(PyObject *o)
 {
 	o->ob_type->tp_free(o);
 }
 
 static PyTypeObject listdir_stat_type = {
 	PyObject_HEAD_INIT(NULL)
 	0,                         /*ob_size*/
 	"osutil.stat",             /*tp_name*/
 	sizeof(struct listdir_stat), /*tp_basicsize*/
 	0,                         /*tp_itemsize*/
 	(destructor)listdir_stat_dealloc, /*tp_dealloc*/
 	0,                         /*tp_print*/
 	0,                         /*tp_getattr*/
 	0,                         /*tp_setattr*/
 	0,                         /*tp_compare*/
 	0,                         /*tp_repr*/
 	0,                         /*tp_as_number*/
 	0,                         /*tp_as_sequence*/
 	0,                         /*tp_as_mapping*/
 	0,                         /*tp_hash */
 	0,                         /*tp_call*/
 	0,                         /*tp_str*/
 	0,                         /*tp_getattro*/
 	0,                         /*tp_setattro*/
 	0,                         /*tp_as_buffer*/
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/
 	"stat objects",            /* tp_doc */
 	0,                         /* tp_traverse */
 	0,                         /* tp_clear */
 	0,                         /* tp_richcompare */
 	0,                         /* tp_weaklistoffset */
 	0,                         /* tp_iter */
 	0,                         /* tp_iternext */
 	0,                         /* tp_methods */
 	0,                         /* tp_members */
 	listdir_stat_getsets,      /* tp_getset */
 	0,                         /* tp_base */
 	0,                         /* tp_dict */
 	0,                         /* tp_descr_get */
 	0,                         /* tp_descr_set */
 	0,                         /* tp_dictoffset */
 	0,                         /* tp_init */
 	0,                         /* tp_alloc */
 	listdir_stat_new,          /* tp_new */
 };
 
-#ifdef AT_SYMLINK_NOFOLLOW
-#define USEFDOPEN 1
-#else
-#define USEFDOPEN 0
-#endif
-
 int entkind(struct dirent *ent)
 {
 #ifdef DT_REG
 	switch (ent->d_type) {
 	case DT_REG: return S_IFREG;
 	case DT_DIR: return S_IFDIR;
 	case DT_LNK: return S_IFLNK;
 	case DT_BLK: return S_IFBLK;
 	case DT_CHR: return S_IFCHR;
 	case DT_FIFO: return S_IFIFO;
 	case DT_SOCK: return S_IFSOCK;
 	}
 #endif
+	return -1;
 }
 
 static PyObject *listdir(PyObject *self, PyObject *args, PyObject *kwargs)
 {
 	static char *kwlist[] = { "path", "stat", NULL };
 	PyObject *statflag = NULL, *list, *elem, *stat, *ret = NULL;
 	char fullpath[PATH_MAX + 10], *path;
-	int pathlen, keepstat, kind, dfd, err;
+	int pathlen, keepstat, kind, dfd = -1, err;
 	struct stat st;
 	struct dirent *ent;
 	DIR *dir;
 
 	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s#|O:listdir", kwlist,
 					 &path, &pathlen, &statflag))
 		goto error_parse;
+	if (pathlen >= PATH_MAX)
+		goto error_parse;
 
 	strncpy(fullpath, path, PATH_MAX);
 	fullpath[pathlen] = '/';
 	keepstat = statflag && PyObject_IsTrue(statflag);
 
-	if (USEFDOPEN) {
+#ifdef AT_SYMLINK_NOFOLLOW
 		dfd = open(path, O_RDONLY);
 		if (dfd == -1) {
 			PyErr_SetFromErrnoWithFilename(PyExc_OSError, path);
 			goto error_parse;
 		}
 		dir = fdopendir(dfd);
-	} else
+#else
 		dir = opendir(path);
+#endif
 	if (!dir) {
 		PyErr_SetFromErrnoWithFilename(PyExc_OSError, path);
 		goto error_dir;
  	}
 
 	list = PyList_New(0);
 	if (!list)
 		goto error_list;
 
 	while ((ent = readdir(dir))) {
 		if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
 			continue;
 
 		kind = entkind(ent);
 		if (kind == -1 || keepstat) {
-			if (USEFDOPEN)
+#ifdef AT_SYMLINK_NOFOLLOW
 				err = fstatat(dfd, ent->d_name, &st,
 					      AT_SYMLINK_NOFOLLOW);
-			else {
+#else
 				strncpy(fullpath + pathlen + 1, ent->d_name,
 					PATH_MAX - pathlen);
 				fullpath[PATH_MAX] = 0;
 				err = lstat(fullpath, &st);
-			}
+#endif
 			if (err == -1) {
 				strncpy(fullpath + pathlen + 1, ent->d_name,
 					PATH_MAX - pathlen);
 				fullpath[PATH_MAX] = 0;
 				PyErr_SetFromErrnoWithFilename(PyExc_OSError,
 							       fullpath);
 				goto error;
 			}
 			kind = st.st_mode & S_IFMT;
 		}
 
 		if (keepstat) {
 			stat = PyObject_CallObject((PyObject *)&listdir_stat_type, NULL);
 			if (!stat)
 				goto error;
 			memcpy(&((struct listdir_stat *)stat)->st, &st, sizeof(st));
 			elem = Py_BuildValue("siN", ent->d_name, kind, stat);
 		} else
 			elem = Py_BuildValue("si", ent->d_name, kind);
 		if (!elem)
 			goto error;
 
 		PyList_Append(list, elem);
 		Py_DECREF(elem);
 	}
 
 	PyList_Sort(list);
 	ret = list;
 	Py_INCREF(ret);
 
 error:
 	Py_DECREF(list);
 error_list:
 	closedir(dir);
 error_dir:
-	if (USEFDOPEN)
+#ifdef AT_SYMLINK_NOFOLLOW
  		close(dfd);
+#endif
 error_parse:
 	return ret;
 }
 
 static char osutil_doc[] = "Native operating system services.";
 
 static PyMethodDef methods[] = {
 	{"listdir", (PyCFunction)listdir, METH_VARARGS | METH_KEYWORDS,
 	 "list a directory\n"},
 	{NULL, NULL}
 };
 
 PyMODINIT_FUNC initosutil(void)
 {
 	if (PyType_Ready(&listdir_stat_type) == -1)
 		return;
 
 	Py_InitModule3("osutil", methods, osutil_doc);
 }