[glibc] Make __getrandom_nocancel set errno and add a _nostatus version

[glibc] Make __getrandom_nocancel set errno and add a _nostatus version

[Andreas K. Huttel]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=5a85786a9005722be7cb9e70f8874a5f1130daea

commit 5a85786a9005722be7cb9e70f8874a5f1130daea
Author: Xi Ruoyao <xry111@xry111.site>
Date:   Thu Jan 4 21:41:20 2024 +0800

    Make __getrandom_nocancel set errno and add a _nostatus version
    
    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>
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
    Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>

Diff:
---
 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);
 }