[Python-checkins] bpo-36352: Clarify fileutils.h documentation (GH-12406)
Victor Stinner
webhook-mailer at python.org
Mon Mar 18 12:47:35 EDT 2019
https://github.com/python/cpython/commit/1be0d1135f5627d0525eab635cf2da441d9cbc08
commit: 1be0d1135f5627d0525eab635cf2da441d9cbc08
branch: master
author: Victor Stinner <vstinner at redhat.com>
committer: GitHub <noreply at github.com>
date: 2019-03-18T17:47:26+01:00
summary:
bpo-36352: Clarify fileutils.h documentation (GH-12406)
The last parameter of _Py_wreadlink(), _Py_wrealpath() and
_Py_wgetcwd() is a length, not a size: number of characters including
the trailing NUL character.
Enhance also documentation of error conditions.
files:
M Include/fileutils.h
M Python/fileutils.c
diff --git a/Include/fileutils.h b/Include/fileutils.h
index 830e56ad367a..0be8b0ae3b31 100644
--- a/Include/fileutils.h
+++ b/Include/fileutils.h
@@ -140,19 +140,25 @@ PyAPI_FUNC(Py_ssize_t) _Py_write_noraise(
PyAPI_FUNC(int) _Py_wreadlink(
const wchar_t *path,
wchar_t *buf,
- size_t bufsiz);
+ /* Number of characters of 'buf' buffer
+ including the trailing NUL character */
+ size_t buflen);
#endif
#ifdef HAVE_REALPATH
PyAPI_FUNC(wchar_t*) _Py_wrealpath(
const wchar_t *path,
wchar_t *resolved_path,
- size_t resolved_path_size);
+ /* Number of characters of 'resolved_path' buffer
+ including the trailing NUL character */
+ size_t resolved_path_len);
#endif
PyAPI_FUNC(wchar_t*) _Py_wgetcwd(
wchar_t *buf,
- size_t size);
+ /* Number of characters of 'buf' buffer
+ including the trailing NUL character */
+ size_t buflen);
PyAPI_FUNC(int) _Py_get_inheritable(int fd);
diff --git a/Python/fileutils.c b/Python/fileutils.c
index 75e015afaec3..0ac690a211cf 100644
--- a/Python/fileutils.c
+++ b/Python/fileutils.c
@@ -1629,10 +1629,12 @@ _Py_write_noraise(int fd, const void *buf, size_t count)
#ifdef HAVE_READLINK
/* Read value of symbolic link. Encode the path to the locale encoding, decode
- the result from the locale encoding. Return -1 on error. */
+ the result from the locale encoding.
+ Return -1 on encoding error, on readlink() error, if the internal buffer is
+ too short, on decoding error, or if 'buf' is too short. */
int
-_Py_wreadlink(const wchar_t *path, wchar_t *buf, size_t bufsiz)
+_Py_wreadlink(const wchar_t *path, wchar_t *buf, size_t buflen)
{
char *cpath;
char cbuf[MAXPATHLEN];
@@ -1659,12 +1661,13 @@ _Py_wreadlink(const wchar_t *path, wchar_t *buf, size_t bufsiz)
errno = EINVAL;
return -1;
}
- if (bufsiz <= r1) {
+ /* wbuf must have space to store the trailing NUL character */
+ if (buflen <= r1) {
PyMem_RawFree(wbuf);
errno = EINVAL;
return -1;
}
- wcsncpy(buf, wbuf, bufsiz);
+ wcsncpy(buf, wbuf, buflen);
PyMem_RawFree(wbuf);
return (int)r1;
}
@@ -1674,11 +1677,12 @@ _Py_wreadlink(const wchar_t *path, wchar_t *buf, size_t bufsiz)
/* Return the canonicalized absolute pathname. Encode path to the locale
encoding, decode the result from the locale encoding.
- Return NULL on error. */
+ Return NULL on encoding error, realpath() error, decoding error
+ or if 'resolved_path' is too short. */
wchar_t*
_Py_wrealpath(const wchar_t *path,
- wchar_t *resolved_path, size_t resolved_path_size)
+ wchar_t *resolved_path, size_t resolved_path_len)
{
char *cpath;
char cresolved_path[MAXPATHLEN];
@@ -1700,12 +1704,13 @@ _Py_wrealpath(const wchar_t *path,
errno = EINVAL;
return NULL;
}
- if (resolved_path_size <= r) {
+ /* wresolved_path must have space to store the trailing NUL character */
+ if (resolved_path_len <= r) {
PyMem_RawFree(wresolved_path);
errno = EINVAL;
return NULL;
}
- wcsncpy(resolved_path, wresolved_path, resolved_path_size);
+ wcsncpy(resolved_path, wresolved_path, resolved_path_len);
PyMem_RawFree(wresolved_path);
return resolved_path;
}
@@ -1713,14 +1718,15 @@ _Py_wrealpath(const wchar_t *path,
/* Get the current directory. size is the buffer size in wide characters
including the null character. Decode the path from the locale encoding.
- Return NULL on error. */
+ Return NULL on getcwd() error, on decoding error, or if 'buf' is
+ too short. */
wchar_t*
-_Py_wgetcwd(wchar_t *buf, size_t size)
+_Py_wgetcwd(wchar_t *buf, size_t buflen)
{
#ifdef MS_WINDOWS
- int isize = (int)Py_MIN(size, INT_MAX);
- return _wgetcwd(buf, isize);
+ int ibuflen = (int)Py_MIN(buflen, INT_MAX);
+ return _wgetcwd(buf, ibuflen);
#else
char fname[MAXPATHLEN];
wchar_t *wname;
@@ -1731,11 +1737,12 @@ _Py_wgetcwd(wchar_t *buf, size_t size)
wname = Py_DecodeLocale(fname, &len);
if (wname == NULL)
return NULL;
- if (size <= len) {
+ /* wname must have space to store the trailing NUL character */
+ if (buflen <= len) {
PyMem_RawFree(wname);
return NULL;
}
- wcsncpy(buf, wname, size);
+ wcsncpy(buf, wname, buflen);
PyMem_RawFree(wname);
return buf;
#endif
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