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[PATCH v3] Handle possible vararg promotion of mode_t in open and friends


On some platforms, mode_t is narrower than int and hence promoted to
int when passed through as the optional argument to an open-like
function; on others, mode_t is at least as wide as int and hence
passed through as-is. To accomodate the case where mode_t might be
strictly wider than int (making va_arg(ap, int) wrong to use), use
whatever type mode_t promotes to as the second argument to
va_arg. Rich Felker suggested that this could be obtained simply as
__typeof__(+(mode_t)0) (which works since POSIX insists that mode_t is
an integral type).

Signed-off-by: Rasmus Villemoes <rv@rasmusvillemoes.dk>
---
 include/fcntl.h                          | 4 ++++
 io/open.c                                | 8 ++++----
 io/open64.c                              | 4 ++--
 io/openat.c                              | 4 ++--
 io/openat64.c                            | 4 ++--
 nptl/sem_open.c                          | 2 +-
 sysdeps/mach/hurd/open.c                 | 2 +-
 sysdeps/mach/hurd/openat.c               | 2 +-
 sysdeps/posix/open64.c                   | 4 ++--
 sysdeps/unix/sysv/linux/generic/open.c   | 8 ++++----
 sysdeps/unix/sysv/linux/generic/open64.c | 4 ++--
 sysdeps/unix/sysv/linux/mq_open.c        | 2 +-
 sysdeps/unix/sysv/linux/open64.c         | 4 ++--
 sysdeps/unix/sysv/linux/openat.c         | 2 +-
 14 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/include/fcntl.h b/include/fcntl.h
index a636f38..a9c72f7 100644
--- a/include/fcntl.h
+++ b/include/fcntl.h
@@ -37,6 +37,10 @@ extern int __have_atfcts attribute_hidden;
 #ifdef O_CLOEXEC
 extern int __have_o_cloexec attribute_hidden;
 #endif
+
+/* The correct type to use when retrieving a mode_t argument passed as a vararg.  */
+typedef __typeof__(+(mode_t)0) promoted_mode_t;
+
 #endif
 
 #endif
diff --git a/io/open.c b/io/open.c
index 24aa380..2d85443 100644
--- a/io/open.c
+++ b/io/open.c
@@ -30,7 +30,7 @@ __libc_open (file, oflag)
      const char *file;
      int oflag;
 {
-  int mode;
+  mode_t mode;
 
   if (file == NULL)
     {
@@ -41,9 +41,9 @@ __libc_open (file, oflag)
   if (oflag & O_CREAT)
     {
       va_list arg;
-      va_start(arg, oflag);
-      mode = va_arg(arg, int);
-      va_end(arg);
+      va_start (arg, oflag);
+      mode = va_arg (arg, promoted_mode_t);
+      va_end (arg);
     }
 
   __set_errno (ENOSYS);
diff --git a/io/open64.c b/io/open64.c
index 3f3d2e8..15bada6 100644
--- a/io/open64.c
+++ b/io/open64.c
@@ -28,7 +28,7 @@ __libc_open64 (file, oflag)
      const char *file;
      int oflag;
 {
-  int mode;
+  mode_t mode;
 
   if (file == NULL)
     {
@@ -40,7 +40,7 @@ __libc_open64 (file, oflag)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, int);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
 
diff --git a/io/openat.c b/io/openat.c
index 2d82270..ace651c 100644
--- a/io/openat.c
+++ b/io/openat.c
@@ -38,7 +38,7 @@ __openat (fd, file, oflag)
      const char *file;
      int oflag;
 {
-  int mode;
+  mode_t mode;
 
   if (file == NULL)
     {
@@ -64,7 +64,7 @@ __openat (fd, file, oflag)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, int);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
 
diff --git a/io/openat64.c b/io/openat64.c
index c0c4e19..614fe42 100644
--- a/io/openat64.c
+++ b/io/openat64.c
@@ -31,7 +31,7 @@ __openat64 (fd, file, oflag)
      const char *file;
      int oflag;
 {
-  int mode;
+  mode_t mode;
 
   if (file == NULL)
     {
@@ -57,7 +57,7 @@ __openat64 (fd, file, oflag)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, int);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
 
diff --git a/nptl/sem_open.c b/nptl/sem_open.c
index cf91859..ded29b3 100644
--- a/nptl/sem_open.c
+++ b/nptl/sem_open.c
@@ -291,7 +291,7 @@ sem_open (const char *name, int oflag, ...)
     try_create:
       va_start (ap, oflag);
 
-      mode = va_arg (ap, mode_t);
+      mode = va_arg (ap, promoted_mode_t);
       value = va_arg (ap, unsigned int);
 
       va_end (ap);
diff --git a/sysdeps/mach/hurd/open.c b/sysdeps/mach/hurd/open.c
index 7d9b2de..640a3e4 100644
--- a/sysdeps/mach/hurd/open.c
+++ b/sysdeps/mach/hurd/open.c
@@ -34,7 +34,7 @@ __libc_open (const char *file, int oflag, ...)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, mode_t);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
   else
diff --git a/sysdeps/mach/hurd/openat.c b/sysdeps/mach/hurd/openat.c
index 318cb22..52964b0 100644
--- a/sysdeps/mach/hurd/openat.c
+++ b/sysdeps/mach/hurd/openat.c
@@ -41,7 +41,7 @@ __openat (fd, file, oflag)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, mode_t);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
   else
diff --git a/sysdeps/posix/open64.c b/sysdeps/posix/open64.c
index 64d192a..b43cb27 100644
--- a/sysdeps/posix/open64.c
+++ b/sysdeps/posix/open64.c
@@ -24,13 +24,13 @@
 int
 __libc_open64 (const char *file, int oflag, ...)
 {
-  int mode = 0;
+  mode_t mode = 0;
 
   if (oflag & O_CREAT)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, int);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
 
diff --git a/sysdeps/unix/sysv/linux/generic/open.c b/sysdeps/unix/sysv/linux/generic/open.c
index 4f73fa0..a1c616f 100644
--- a/sysdeps/unix/sysv/linux/generic/open.c
+++ b/sysdeps/unix/sysv/linux/generic/open.c
@@ -27,13 +27,13 @@
 int
 __libc_open (const char *file, int oflag, ...)
 {
-  int mode = 0;
+  mode_t mode = 0;
 
   if (oflag & O_CREAT)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, int);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
 
@@ -57,13 +57,13 @@ weak_alias (__libc_open, open)
 int
 __open_nocancel (const char *file, int oflag, ...)
 {
-  int mode = 0;
+  mode_t mode = 0;
 
   if (oflag & O_CREAT)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, int);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
 
diff --git a/sysdeps/unix/sysv/linux/generic/open64.c b/sysdeps/unix/sysv/linux/generic/open64.c
index 93d79e3..c707db8 100644
--- a/sysdeps/unix/sysv/linux/generic/open64.c
+++ b/sysdeps/unix/sysv/linux/generic/open64.c
@@ -27,13 +27,13 @@
 int
 __libc_open64 (const char *file, int oflag, ...)
 {
-  int mode = 0;
+  mode_t mode = 0;
 
   if (oflag & O_CREAT)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, int);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
 
diff --git a/sysdeps/unix/sysv/linux/mq_open.c b/sysdeps/unix/sysv/linux/mq_open.c
index 38194ac..4fa5632 100644
--- a/sysdeps/unix/sysv/linux/mq_open.c
+++ b/sysdeps/unix/sysv/linux/mq_open.c
@@ -47,7 +47,7 @@ __mq_open (const char *name, int oflag, ...)
       va_list ap;
 
       va_start (ap, oflag);
-      mode = va_arg (ap, mode_t);
+      mode = va_arg (ap, promoted_mode_t);
       attr = va_arg (ap, struct mq_attr *);
       va_end (ap);
     }
diff --git a/sysdeps/unix/sysv/linux/open64.c b/sysdeps/unix/sysv/linux/open64.c
index 0d63806..ac3e72a 100644
--- a/sysdeps/unix/sysv/linux/open64.c
+++ b/sysdeps/unix/sysv/linux/open64.c
@@ -26,13 +26,13 @@
 int
 __libc_open64 (const char *file, int oflag, ...)
 {
-  int mode = 0;
+  mode_t mode = 0;
 
   if (oflag & O_CREAT)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, int);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
 
diff --git a/sysdeps/unix/sysv/linux/openat.c b/sysdeps/unix/sysv/linux/openat.c
index 36555b9..f9dcda6 100644
--- a/sysdeps/unix/sysv/linux/openat.c
+++ b/sysdeps/unix/sysv/linux/openat.c
@@ -71,7 +71,7 @@ __OPENAT (fd, file, oflag)
     {
       va_list arg;
       va_start (arg, oflag);
-      mode = va_arg (arg, mode_t);
+      mode = va_arg (arg, promoted_mode_t);
       va_end (arg);
     }
 
-- 
1.9.2


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