From 7bd89bf36685213cddb980add31777ab1c67fd49 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Wed, 7 Sep 2016 17:06:54 +0200 Subject: [PATCH] mingw: abort on invalid strftime formats On Windows, strftime() does not silently ignore invalid formats, but warns about them and then returns 0 and sets errno to EINVAL. Unfortunately, Git does not expect such a behavior, as it disagrees with strftime()'s semantics on Linux. As a consequence, Git misinterprets the return value 0 as "I need more space" and grows the buffer. As the larger buffer does not fix the format, the buffer grows and grows and grows until we are out of memory and abort. Ideally, we would switch off the parameter validation just for strftime(), but we cannot even override the invalid parameter handler via _set_thread_local_invalid_parameter_handler() using MINGW because that function is not declared. Even _set_invalid_parameter_handler(), which *is* declared, does not help, as it simply does... nothing. So let's just bite the bullet and override strftime() for MINGW and abort on an invalid format string. While this does not provide the best user experience, it is the best we can do. See https://msdn.microsoft.com/en-us/library/fe06s4ak.aspx for more details. This fixes https://github.com/git-for-windows/git/issues/863 Signed-off-by: Johannes Schindelin --- compat/mingw.c | 11 +++++++++++ compat/mingw.h | 3 +++ 2 files changed, 14 insertions(+) diff --git a/compat/mingw.c b/compat/mingw.c index 3fbfda5978b7bb..69ac1e1957d288 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -759,6 +759,17 @@ int mingw_utime (const char *file_name, const struct utimbuf *times) return rc; } +#undef strftime +size_t mingw_strftime(char *s, size_t max, + const char *format, const struct tm *tm) +{ + size_t ret = strftime(s, max, format, tm); + + if (!ret && errno == EINVAL) + die("invalid strftime format: '%s'", format); + return ret; +} + unsigned int sleep (unsigned int seconds) { Sleep(seconds*1000); diff --git a/compat/mingw.h b/compat/mingw.h index 034fff9479d03d..e66d2d9b40142e 100644 --- a/compat/mingw.h +++ b/compat/mingw.h @@ -361,6 +361,9 @@ int mingw_fstat(int fd, struct stat *buf); int mingw_utime(const char *file_name, const struct utimbuf *times); #define utime mingw_utime +size_t mingw_strftime(char *s, size_t max, + const char *format, const struct tm *tm); +#define strftime mingw_strftime pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **env, const char *dir,