[PATCH v2] Make __getrandom_nocancel set errno and add a _nostatus version

[PATCH v2] Make __getrandom_nocancel set errno and add a _nostatus version

[Xi Ruoyao]

The __getrandom_nocancel function returns errors as negative values
instead of errno.  This is inconsistent with other _nocancel functions
and it breaks "TEMP_FAILURE_RETRY (__getrandom_nocancel (p, n, 0))" in
__arc4random_buf.  Use INLINE_SYSCALL_CALL instead of
INTERNAL_SYSCALL_CALL to fix this issue.

But __getrandom_nocancel has been avoiding from touching errno for a
reason, see BZ 29624.  So add a __getrandom_nocancel_nostatus function
and use it in tcache_key_initialize.

Signed-off-by: Xi Ruoyao <xry111@xry111.site>
---

Superseds the incorrect patch [v1].

[v1]:https://sourceware.org/pipermail/libc-alpha/2024-January/153727.html.

 malloc/malloc.c                      | 4 +++-
 sysdeps/generic/not-cancel.h         | 2 ++
 sysdeps/mach/hurd/not-cancel.h       | 7 ++++++-
 sysdeps/unix/sysv/linux/not-cancel.h | 8 ++++++++
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/malloc/malloc.c b/malloc/malloc.c
index 198e78a162..bcb6e5b83c 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3139,7 +3139,9 @@ static uintptr_t tcache_key;
 static void
 tcache_key_initialize (void)
 {
-  if (__getrandom_nocancel (&tcache_key, sizeof(tcache_key), GRND_NONBLOCK)
+  /* We need to use the _nostatus version here, see BZ 29624.  */
+  if (__getrandom_nocancel_nostatus (&tcache_key, sizeof(tcache_key),
+				     GRND_NONBLOCK)
       != sizeof (tcache_key))
     {
       tcache_key = random_bits ();
diff --git a/sysdeps/generic/not-cancel.h b/sysdeps/generic/not-cancel.h
index d9a6cba443..2dd1064600 100644
--- a/sysdeps/generic/not-cancel.h
+++ b/sysdeps/generic/not-cancel.h
@@ -51,6 +51,8 @@
   __fcntl64 (fd, cmd, __VA_ARGS__)
 #define __getrandom_nocancel(buf, size, flags) \
   __getrandom (buf, size, flags)
+#define __getrandom_nocancel_nostatus(buf, size, flags) \
+  __getrandom (buf, size, flags)
 #define __poll_infinity_nocancel(fds, nfds) \
   __poll (fds, nfds, -1)
 
diff --git a/sysdeps/mach/hurd/not-cancel.h b/sysdeps/mach/hurd/not-cancel.h
index 411f5796ae..69fb3c00ef 100644
--- a/sysdeps/mach/hurd/not-cancel.h
+++ b/sysdeps/mach/hurd/not-cancel.h
@@ -76,8 +76,10 @@ __typeof (__fcntl) __fcntl_nocancel;
 #define __fcntl64_nocancel(...) \
   __fcntl_nocancel (__VA_ARGS__)
 
+/* Non cancellable getrandom syscall that does not also set errno in case of
+   failure.  */
 static inline ssize_t
-__getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
+__getrandom_nocancel_nostatus (void *buf, size_t buflen, unsigned int flags)
 {
   int save_errno = errno;
   ssize_t r = __getrandom (buf, buflen, flags);
@@ -86,6 +88,9 @@ __getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
   return r;
 }
 
+#define __getrandom_nocancel(buf, size, flags) \
+  __getrandom (buf, size, flags)
+
 #define __poll_infinity_nocancel(fds, nfds) \
   __poll (fds, nfds, -1)
 
diff --git a/sysdeps/unix/sysv/linux/not-cancel.h b/sysdeps/unix/sysv/linux/not-cancel.h
index 50483d9e74..2a7585b73f 100644
--- a/sysdeps/unix/sysv/linux/not-cancel.h
+++ b/sysdeps/unix/sysv/linux/not-cancel.h
@@ -85,6 +85,14 @@ __writev_nocancel_nostatus (int fd, const struct iovec *iov, int iovcnt)
 
 static inline ssize_t
 __getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
+{
+  return INLINE_SYSCALL_CALL (getrandom, buf, buflen, flags);
+}
+
+/* Non cancellable getrandom syscall that does not also set errno in case of
+   failure.  */
+static inline ssize_t
+__getrandom_nocancel_nostatus (void *buf, size_t buflen, unsigned int flags)
 {
   return INTERNAL_SYSCALL_CALL (getrandom, buf, buflen, flags);
 }
-- 
2.43.0

Ping: [PATCH v2] Make __getrandom_nocancel set errno and add a _nostatus version

[Xi Ruoyao]

Ping.  Sorry for an abnormal time period but now we are close to hard
freeze, and the next review meeting won't happen before the hard freeze.

On Thu, 2024-01-04 at 21:41 +0800, Xi Ruoyao wrote:
> The __getrandom_nocancel function returns errors as negative values
> instead of errno.  This is inconsistent with other _nocancel functions
> and it breaks "TEMP_FAILURE_RETRY (__getrandom_nocancel (p, n, 0))" in
> __arc4random_buf.  Use INLINE_SYSCALL_CALL instead of
> INTERNAL_SYSCALL_CALL to fix this issue.
> 
> But __getrandom_nocancel has been avoiding from touching errno for a
> reason, see BZ 29624.  So add a __getrandom_nocancel_nostatus function
> and use it in tcache_key_initialize.
> 
> Signed-off-by: Xi Ruoyao <xry111@xry111.site>
> ---
> 
> Superseds the incorrect patch [v1].
> 
> [v1]:https://sourceware.org/pipermail/libc-alpha/2024-January/153727.html.
> 
>  malloc/malloc.c                      | 4 +++-
>  sysdeps/generic/not-cancel.h         | 2 ++
>  sysdeps/mach/hurd/not-cancel.h       | 7 ++++++-
>  sysdeps/unix/sysv/linux/not-cancel.h | 8 ++++++++
>  4 files changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/malloc/malloc.c b/malloc/malloc.c
> index 198e78a162..bcb6e5b83c 100644
> --- a/malloc/malloc.c
> +++ b/malloc/malloc.c
> @@ -3139,7 +3139,9 @@ static uintptr_t tcache_key;
>  static void
>  tcache_key_initialize (void)
>  {
> -  if (__getrandom_nocancel (&tcache_key, sizeof(tcache_key), GRND_NONBLOCK)
> +  /* We need to use the _nostatus version here, see BZ 29624.  */
> +  if (__getrandom_nocancel_nostatus (&tcache_key, sizeof(tcache_key),
> +				     GRND_NONBLOCK)
>        != sizeof (tcache_key))
>      {
>        tcache_key = random_bits ();
> diff --git a/sysdeps/generic/not-cancel.h b/sysdeps/generic/not-cancel.h
> index d9a6cba443..2dd1064600 100644
> --- a/sysdeps/generic/not-cancel.h
> +++ b/sysdeps/generic/not-cancel.h
> @@ -51,6 +51,8 @@
>    __fcntl64 (fd, cmd, __VA_ARGS__)
>  #define __getrandom_nocancel(buf, size, flags) \
>    __getrandom (buf, size, flags)
> +#define __getrandom_nocancel_nostatus(buf, size, flags) \
> +  __getrandom (buf, size, flags)
>  #define __poll_infinity_nocancel(fds, nfds) \
>    __poll (fds, nfds, -1)
>  
> diff --git a/sysdeps/mach/hurd/not-cancel.h b/sysdeps/mach/hurd/not-cancel.h
> index 411f5796ae..69fb3c00ef 100644
> --- a/sysdeps/mach/hurd/not-cancel.h
> +++ b/sysdeps/mach/hurd/not-cancel.h
> @@ -76,8 +76,10 @@ __typeof (__fcntl) __fcntl_nocancel;
>  #define __fcntl64_nocancel(...) \
>    __fcntl_nocancel (__VA_ARGS__)
>  
> +/* Non cancellable getrandom syscall that does not also set errno in case of
> +   failure.  */
>  static inline ssize_t
> -__getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
> +__getrandom_nocancel_nostatus (void *buf, size_t buflen, unsigned int flags)
>  {
>    int save_errno = errno;
>    ssize_t r = __getrandom (buf, buflen, flags);
> @@ -86,6 +88,9 @@ __getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
>    return r;
>  }
>  
> +#define __getrandom_nocancel(buf, size, flags) \
> +  __getrandom (buf, size, flags)
> +
>  #define __poll_infinity_nocancel(fds, nfds) \
>    __poll (fds, nfds, -1)
>  
> diff --git a/sysdeps/unix/sysv/linux/not-cancel.h b/sysdeps/unix/sysv/linux/not-cancel.h
> index 50483d9e74..2a7585b73f 100644
> --- a/sysdeps/unix/sysv/linux/not-cancel.h
> +++ b/sysdeps/unix/sysv/linux/not-cancel.h
> @@ -85,6 +85,14 @@ __writev_nocancel_nostatus (int fd, const struct iovec *iov, int iovcnt)
>  
>  static inline ssize_t
>  __getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
> +{
> +  return INLINE_SYSCALL_CALL (getrandom, buf, buflen, flags);
> +}
> +
> +/* Non cancellable getrandom syscall that does not also set errno in case of
> +   failure.  */
> +static inline ssize_t
> +__getrandom_nocancel_nostatus (void *buf, size_t buflen, unsigned int flags)
>  {
>    return INTERNAL_SYSCALL_CALL (getrandom, buf, buflen, flags);
>  }

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University

Re: [PATCH v2] Make __getrandom_nocancel set errno and add a _nostatus version

[Adhemerval Zanella Netto]

On 04/01/24 10:41, Xi Ruoyao wrote:
> The __getrandom_nocancel function returns errors as negative values
> instead of errno.  This is inconsistent with other _nocancel functions
> and it breaks "TEMP_FAILURE_RETRY (__getrandom_nocancel (p, n, 0))" in
> __arc4random_buf.  Use INLINE_SYSCALL_CALL instead of
> INTERNAL_SYSCALL_CALL to fix this issue.
> 
> But __getrandom_nocancel has been avoiding from touching errno for a
> reason, see BZ 29624.  So add a __getrandom_nocancel_nostatus function
> and use it in tcache_key_initialize.
> 
> Signed-off-by: Xi Ruoyao <xry111@xry111.site>

LGTM, thanks.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> ---
> 
> Superseds the incorrect patch [v1].
> 
> [v1]:https://sourceware.org/pipermail/libc-alpha/2024-January/153727.html.
> 
>  malloc/malloc.c                      | 4 +++-
>  sysdeps/generic/not-cancel.h         | 2 ++
>  sysdeps/mach/hurd/not-cancel.h       | 7 ++++++-
>  sysdeps/unix/sysv/linux/not-cancel.h | 8 ++++++++
>  4 files changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/malloc/malloc.c b/malloc/malloc.c
> index 198e78a162..bcb6e5b83c 100644
> --- a/malloc/malloc.c
> +++ b/malloc/malloc.c
> @@ -3139,7 +3139,9 @@ static uintptr_t tcache_key;
>  static void
>  tcache_key_initialize (void)
>  {
> -  if (__getrandom_nocancel (&tcache_key, sizeof(tcache_key), GRND_NONBLOCK)
> +  /* We need to use the _nostatus version here, see BZ 29624.  */
> +  if (__getrandom_nocancel_nostatus (&tcache_key, sizeof(tcache_key),
> +				     GRND_NONBLOCK)
>        != sizeof (tcache_key))
>      {
>        tcache_key = random_bits ();

Ok.

> diff --git a/sysdeps/generic/not-cancel.h b/sysdeps/generic/not-cancel.h
> index d9a6cba443..2dd1064600 100644
> --- a/sysdeps/generic/not-cancel.h
> +++ b/sysdeps/generic/not-cancel.h
> @@ -51,6 +51,8 @@
>    __fcntl64 (fd, cmd, __VA_ARGS__)
>  #define __getrandom_nocancel(buf, size, flags) \
>    __getrandom (buf, size, flags)
> +#define __getrandom_nocancel_nostatus(buf, size, flags) \
> +  __getrandom (buf, size, flags)
>  #define __poll_infinity_nocancel(fds, nfds) \
>    __poll (fds, nfds, -1)
>  

Ok.

> diff --git a/sysdeps/mach/hurd/not-cancel.h b/sysdeps/mach/hurd/not-cancel.h
> index 411f5796ae..69fb3c00ef 100644
> --- a/sysdeps/mach/hurd/not-cancel.h
> +++ b/sysdeps/mach/hurd/not-cancel.h
> @@ -76,8 +76,10 @@ __typeof (__fcntl) __fcntl_nocancel;
>  #define __fcntl64_nocancel(...) \
>    __fcntl_nocancel (__VA_ARGS__)
>  
> +/* Non cancellable getrandom syscall that does not also set errno in case of
> +   failure.  */
>  static inline ssize_t
> -__getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
> +__getrandom_nocancel_nostatus (void *buf, size_t buflen, unsigned int flags)
>  {
>    int save_errno = errno;
>    ssize_t r = __getrandom (buf, buflen, flags);
> @@ -86,6 +88,9 @@ __getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
>    return r;
>  }
>  
> +#define __getrandom_nocancel(buf, size, flags) \
> +  __getrandom (buf, size, flags)
> +
>  #define __poll_infinity_nocancel(fds, nfds) \
>    __poll (fds, nfds, -1)
>  

Ok.

> diff --git a/sysdeps/unix/sysv/linux/not-cancel.h b/sysdeps/unix/sysv/linux/not-cancel.h
> index 50483d9e74..2a7585b73f 100644
> --- a/sysdeps/unix/sysv/linux/not-cancel.h
> +++ b/sysdeps/unix/sysv/linux/not-cancel.h
> @@ -85,6 +85,14 @@ __writev_nocancel_nostatus (int fd, const struct iovec *iov, int iovcnt)
>  
>  static inline ssize_t
>  __getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
> +{
> +  return INLINE_SYSCALL_CALL (getrandom, buf, buflen, flags);
> +}
> +
> +/* Non cancellable getrandom syscall that does not also set errno in case of
> +   failure.  */
> +static inline ssize_t
> +__getrandom_nocancel_nostatus (void *buf, size_t buflen, unsigned int flags)
>  {
>    return INTERNAL_SYSCALL_CALL (getrandom, buf, buflen, flags);
>  }


Ok.