| Message ID | 2c39f9a04f98fc3d365c80ce57e8edce305846fb.1574867409.git.congdanhqx@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drop non-reentrant time usage | expand |
Hi Danh, On Wed, 27 Nov 2019, Doan Tran Cong Danh wrote: > Since Windows doesn't provide gmtime_r(3) and localtime_r(3), > we're providing a compat version by using non-reentrant gmtime(3) and > localtime(3) as backend. Then, we copy the returned data into the > buffer. > > By doing that, in case of failure, we will dereference a NULL pointer > returned by gmtime(3), and localtime(3), and we always return a valid > pointer instead of NULL. > > Drop the memcpy(3) by using gmtime_s, and localtime_s as backend on s/and localtime_s/and use localtime_s()/ Otherwise, this looks good to me, thank you! Ciao, Dscho > Windows, and make sure we will return NULL in case of failure. > > Cc: Johannes Sixt <j6t@kdbg.org> > Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de> > Signed-off-by: Doan Tran Cong Danh <congdanhqx@gmail.com> > --- > compat/mingw.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/compat/mingw.c b/compat/mingw.c > index fe609239dd..7b21f4eee5 100644 > --- a/compat/mingw.c > +++ b/compat/mingw.c > @@ -1,6 +1,7 @@ > #include "../git-compat-util.h" > #include "win32.h" > #include <conio.h> > +#include <errno.h> > #include <wchar.h> > #include "../strbuf.h" > #include "../run-command.h" > @@ -986,16 +987,16 @@ int pipe(int filedes[2]) > > struct tm *gmtime_r(const time_t *timep, struct tm *result) > { > - /* gmtime() in MSVCRT.DLL is thread-safe, but not reentrant */ > - memcpy(result, gmtime(timep), sizeof(struct tm)); > - return result; > + if (gmtime_s(result, timep) == 0) > + return result; > + return NULL; > } > > struct tm *localtime_r(const time_t *timep, struct tm *result) > { > - /* localtime() in MSVCRT.DLL is thread-safe, but not reentrant */ > - memcpy(result, localtime(timep), sizeof(struct tm)); > - return result; > + if (localtime_s(result, timep) == 0) > + return result; > + return NULL; > } > > char *mingw_getcwd(char *pointer, int len) > -- > 2.24.0.158.gd77a74f4dd.dirty > >
Hi Danh, On Wed, 27 Nov 2019, Doan Tran Cong Danh wrote: > diff --git a/compat/mingw.c b/compat/mingw.c > index fe609239dd..7b21f4eee5 100644 > --- a/compat/mingw.c > +++ b/compat/mingw.c > @@ -1,6 +1,7 @@ > #include "../git-compat-util.h" > #include "win32.h" > #include <conio.h> > +#include <errno.h> I actually overlooked this. Please drop this hunk, it should not be needed (and might break things in the MSVC build). Thanks, Dscho > #include <wchar.h> > #include "../strbuf.h" > #include "../run-command.h" > @@ -986,16 +987,16 @@ int pipe(int filedes[2]) > > struct tm *gmtime_r(const time_t *timep, struct tm *result) > { > - /* gmtime() in MSVCRT.DLL is thread-safe, but not reentrant */ > - memcpy(result, gmtime(timep), sizeof(struct tm)); > - return result; > + if (gmtime_s(result, timep) == 0) > + return result; > + return NULL; > } > > struct tm *localtime_r(const time_t *timep, struct tm *result) > { > - /* localtime() in MSVCRT.DLL is thread-safe, but not reentrant */ > - memcpy(result, localtime(timep), sizeof(struct tm)); > - return result; > + if (localtime_s(result, timep) == 0) > + return result; > + return NULL; > } > > char *mingw_getcwd(char *pointer, int len) > -- > 2.24.0.158.gd77a74f4dd.dirty > >
On 2019-11-27 20:39:27+0100, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote: > Hi Danh, > > On Wed, 27 Nov 2019, Doan Tran Cong Danh wrote: > > > diff --git a/compat/mingw.c b/compat/mingw.c > > index fe609239dd..7b21f4eee5 100644 > > --- a/compat/mingw.c > > +++ b/compat/mingw.c > > @@ -1,6 +1,7 @@ > > #include "../git-compat-util.h" > > #include "win32.h" > > #include <conio.h> > > +#include <errno.h> > > I actually overlooked this. Please drop this hunk, it should not be needed > (and might break things in the MSVC build). Oops, originally, I intended to reset errno after {gm,local}time_s Found out it's unneccessary later but I forgot to drop this hunk. I'll fix it.
diff --git a/compat/mingw.c b/compat/mingw.c index fe609239dd..7b21f4eee5 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -1,6 +1,7 @@ #include "../git-compat-util.h" #include "win32.h" #include <conio.h> +#include <errno.h> #include <wchar.h> #include "../strbuf.h" #include "../run-command.h" @@ -986,16 +987,16 @@ int pipe(int filedes[2]) struct tm *gmtime_r(const time_t *timep, struct tm *result) { - /* gmtime() in MSVCRT.DLL is thread-safe, but not reentrant */ - memcpy(result, gmtime(timep), sizeof(struct tm)); - return result; + if (gmtime_s(result, timep) == 0) + return result; + return NULL; } struct tm *localtime_r(const time_t *timep, struct tm *result) { - /* localtime() in MSVCRT.DLL is thread-safe, but not reentrant */ - memcpy(result, localtime(timep), sizeof(struct tm)); - return result; + if (localtime_s(result, timep) == 0) + return result; + return NULL; } char *mingw_getcwd(char *pointer, int len)
Since Windows doesn't provide gmtime_r(3) and localtime_r(3), we're providing a compat version by using non-reentrant gmtime(3) and localtime(3) as backend. Then, we copy the returned data into the buffer. By doing that, in case of failure, we will dereference a NULL pointer returned by gmtime(3), and localtime(3), and we always return a valid pointer instead of NULL. Drop the memcpy(3) by using gmtime_s, and localtime_s as backend on Windows, and make sure we will return NULL in case of failure. Cc: Johannes Sixt <j6t@kdbg.org> Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Doan Tran Cong Danh <congdanhqx@gmail.com> --- compat/mingw.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)