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author | Guido van Rossum <guido@python.org> | 1999-02-23 00:00:10 (GMT) |
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committer | Guido van Rossum <guido@python.org> | 1999-02-23 00:00:10 (GMT) |
commit | c222ec28a54089da3b15da5e06fb7f78ba294866 (patch) | |
tree | d0f54443646dc4e38e2d36ffeebb8349f8668952 | |
parent | 1ec71cb5563b8444246559d0935418610546f13b (diff) | |
download | cpython-c222ec28a54089da3b15da5e06fb7f78ba294866.zip cpython-c222ec28a54089da3b15da5e06fb7f78ba294866.tar.gz cpython-c222ec28a54089da3b15da5e06fb7f78ba294866.tar.bz2 |
Patch by Tadayoshi Funaba (with some changes) to be smarter about
guessing what happened when strftime() returns 0. Is it buffer
overflow or was the result simply 0 bytes long? (This happens for an
empty format string, or when the format string is a single %Z and the
timezone is unknown.) if the buffer is at least 256 times as long as
the format, assume the latter.
-rw-r--r-- | Modules/timemodule.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/Modules/timemodule.c b/Modules/timemodule.c index 50abf00..b65bfbc 100644 --- a/Modules/timemodule.c +++ b/Modules/timemodule.c @@ -366,6 +366,7 @@ time_strftime(self, args) PyObject *tup; struct tm buf; const char *fmt; + int fmtlen, buflen; char *outbuf = 0; int i; @@ -373,25 +374,30 @@ time_strftime(self, args) if (!PyArg_ParseTuple(args, "sO", &fmt, &tup) || !gettmarg(tup, &buf)) return NULL; + fmtlen = strlen(fmt); + /* I hate these functions that presume you know how big the output * will be ahead of time... */ - for (i = 1024 ; i <= 8192 ; i += 1024) { + for (i = 1024; ; i += i) { outbuf = malloc(i); if (outbuf == NULL) { return PyErr_NoMemory(); } - if (strftime(outbuf, i-1, fmt, &buf) != 0) { + buflen = strftime(outbuf, i, fmt, &buf); + if (buflen > 0 || i >= 256 * fmtlen) { + /* If the buffer is 256 times as long as the format, + it's probably not failing for lack of room! + More likely, the format yields an empty result, + e.g. an empty format, or %Z when the timezone + is unknown. */ PyObject *ret; - ret = PyString_FromString(outbuf); + ret = PyString_FromStringAndSize(outbuf, buflen); free(outbuf); return ret; } free(outbuf); } - PyErr_SetString(PyExc_ValueError, - "bad strftime format or result too big"); - return NULL; } static char strftime_doc[] = |