diff options
Diffstat (limited to 'Objects/fileobject.c')
| -rw-r--r-- | Objects/fileobject.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/Objects/fileobject.c b/Objects/fileobject.c index b43bf85b87..ced07684fd 100644 --- a/Objects/fileobject.c +++ b/Objects/fileobject.c @@ -1001,6 +1001,7 @@ getline_via_fgets(FILE *fp) size_t nfree; /* # of free buffer slots; pvend-pvfree */ size_t total_v_size; /* total # of slots in buffer */ size_t increment; /* amount to increment the buffer */ + size_t prev_v_size; /* Optimize for normal case: avoid _PyString_Resize if at all * possible via first reading into stack buffer "buf". @@ -1115,8 +1116,11 @@ getline_via_fgets(FILE *fp) /* expand buffer and try again */ assert(*(pvend-1) == '\0'); increment = total_v_size >> 2; /* mild exponential growth */ + prev_v_size = total_v_size; total_v_size += increment; - if (total_v_size > PY_SSIZE_T_MAX) { + /* check for overflow */ + if (total_v_size <= prev_v_size || + total_v_size > PY_SSIZE_T_MAX) { PyErr_SetString(PyExc_OverflowError, "line is longer than a Python string can hold"); Py_DECREF(v); @@ -1125,7 +1129,7 @@ getline_via_fgets(FILE *fp) if (_PyString_Resize(&v, (int)total_v_size) < 0) return NULL; /* overwrite the trailing null byte */ - pvfree = BUF(v) + (total_v_size - increment - 1); + pvfree = BUF(v) + (prev_v_size - 1); } if (BUF(v) + total_v_size != p) _PyString_Resize(&v, p - BUF(v)); |