[PATCH v3 2/2] malloc: Do not clobber errno on __getrandom_nocancel (BZ #29624)

[Wilco Dijkstra]

Hi Adhemerval,

This looks good to me assuming Hurd is 32-bit only.

Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>

Cheers,
Wilco


From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
 
Use INTERNAL_SYSCALL_CALL instead of INLINE_SYSCALL_CALL.  This
requires emulate the semantic for hurd call (so __arc4random_buf
uses the fallback).

Checked on x86_64-linux-gnu.
---
 stdlib/arc4random.c                  |  2 +-
 sysdeps/mach/hurd/not-cancel.h       | 12 ++++++++++--
 sysdeps/unix/sysv/linux/not-cancel.h |  2 +-
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/stdlib/arc4random.c b/stdlib/arc4random.c
index 960a38f295..c126c601bf 100644
--- a/stdlib/arc4random.c
+++ b/stdlib/arc4random.c
@@ -51,7 +51,7 @@ __arc4random_buf (void *p, size_t n)
           n -= l;
           continue; /* Interrupted by a signal; keep going.  */
         }
-      else if (l < 0 && errno == ENOSYS)
+      else if (l == -ENOSYS)
         break; /* No syscall, so fallback to /dev/urandom.  */
       arc4random_getrandom_failure ();
     }
diff --git a/sysdeps/mach/hurd/not-cancel.h b/sysdeps/mach/hurd/not-cancel.h
index ae58b734e3..5d2d2b4b8a 100644
--- a/sysdeps/mach/hurd/not-cancel.h
+++ b/sysdeps/mach/hurd/not-cancel.h
@@ -25,6 +25,7 @@
 #include <sys/wait.h>
 #include <time.h>
 #include <sys/uio.h>
+#include <sys/random.h>
 #include <hurd.h>
 #include <hurd/fd.h>
 
@@ -75,8 +76,15 @@ __typeof (__fcntl) __fcntl_nocancel;
 #define __fcntl64_nocancel(...) \
   __fcntl_nocancel (__VA_ARGS__)
 
-#define __getrandom_nocancel(buf, size, flags) \
-  __getrandom (buf, size, flags)
+static inline int
+__getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
+{
+  int save_errno = errno;
+  int r = __getrandom (buf, buflen, flags);
+  r = r == -1 ? -errno : r;
+  __set_errno (save_errno);
+  return r;
+}
 
 #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 cf35c8bfc9..93615de681 100644
--- a/sysdeps/unix/sysv/linux/not-cancel.h
+++ b/sysdeps/unix/sysv/linux/not-cancel.h
@@ -71,7 +71,7 @@ __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);
+  return INTERNAL_SYSCALL_CALL (getrandom, buf, buflen, flags);
 }
 
 static inline int
-- 
2.34.1