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Re: [PATCH 2/2] New internal function __access_noerrno
On 16/11/2016 11:27, Adhemerval Zanella wrote:
>
>
> On 10/11/2016 16:31, Adhemerval Zanella wrote:
>>
>>
>> On 10/11/2016 15:53, Siddhesh Poyarekar wrote:
>>> On Thursday 10 November 2016 10:34 PM, Adhemerval Zanella wrote:
>>>> This ia follow up patch for tunables requirement [1]. It Implement
>>>> an internal version of __access called __access_noerrno that
>>>> avoids setting errno. This is useful to check accessibility of files
>>>> very early on in process startup i.e. before TLS setup. This allows
>>>> tunables to replace MALLOC_CHECK_ safely (i.e. check existence of
>>>> /etc/suid-debug to enable/disable MALLOC_CHECK) and at the same time
>>>> initialize very early so that it can override IFUNCs.
>>>
>>> I think someone else should also review and ack this one, but I'll do a
>>> review round anyway.
>>
>> Thanks, I fixes all my mistakes locally. It would be good to have a
>> ack for nacl/hurd before pushing it.
>
> I tried both hurd [1] and nacl [2] environments to check the build but
> without success. Hurd VM does not boot with a recent qemu (2.7.50) and
> NaCL toolchain seems stuck in a ancient gcc version (4.4.7). Since I
> this patch won't break any functionality (since it only adds a new
> symbol), I see it should be safe to push.
>
> [1] https://people.debian.org/~sthibault/hurd-i386/README
> [2] https://developer.chrome.com/native-client/sdk/download
Updated version below:
* hurd/hurd.h (__hurd_fail_noerrno): New function.
* include/unistd.h [IS_IN (rtld) || !defined SHARED]: Declare
__access_noerrno.
* io/access.c (__access_noerrno): New function.
* sysdeps/mach/hurd/access.c (hurd_fail_seterrno): New function.
(hurd_fail_seterrno): Likewise.
(access_common): Likewise.
(__access_noerrno): Likewise.
* sysdeps/nacl/access.c (__access_noerrno): Likewise.
* sysdeps/unix/sysv/linux/access.c (__access_noerrno): Likewise.
* sysdeps/nacl/nacl-interfaces.h (NACL_CALL_NOERRNO): New
macro.
---
ChangeLog | 15 +++++++++++++++
hurd/hurd.h | 29 +++++++++++++++++++++++++++++
include/unistd.h | 6 ++++++
io/access.c | 7 +++++++
sysdeps/mach/hurd/access.c | 37 +++++++++++++++++++++++++++++++------
sysdeps/nacl/access.c | 7 +++++++
sysdeps/nacl/nacl-interfaces.h | 4 ++++
sysdeps/unix/sysv/linux/access.c | 15 +++++++++++++++
8 files changed, 114 insertions(+), 6 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index dfa48e4..b2e5b68 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2016-11-16 Adhemerval Zanella <adhemerval.zanella@linaro.org>
+
+ * hurd/hurd.h (__hurd_fail_noerrno): New function.
+ * include/unistd.h [IS_IN (rtld) || !defined SHARED]: Declare
+ __access_noerrno.
+ * io/access.c (__access_noerrno): New function.
+ * sysdeps/mach/hurd/access.c (hurd_fail_seterrno): New function.
+ (hurd_fail_seterrno): Likewise.
+ (access_common): Likewise.
+ (__access_noerrno): Likewise.
+ * sysdeps/nacl/access.c (__access_noerrno): Likewise.
+ * sysdeps/unix/sysv/linux/access.c (__access_noerrno): Likewise.
+ * sysdeps/nacl/nacl-interfaces.h (NACL_CALL_NOERRNO): New
+ macro.
+
2016-11-16 Joseph Myers <joseph@codesourcery.com>
* sysdeps/unix/sysv/linux/sh/sh4/register-dump.h (register_dump):
diff --git a/hurd/hurd.h b/hurd/hurd.h
index ec07827..c089d4c 100644
--- a/hurd/hurd.h
+++ b/hurd/hurd.h
@@ -75,6 +75,35 @@ __hurd_fail (error_t err)
errno = err;
return -1;
}
+
+_HURD_H_EXTERN_INLINE int
+__hurd_fail_noerrno (error_t err)
+{
+ switch (err)
+ {
+ case EMACH_SEND_INVALID_DEST:
+ case EMIG_SERVER_DIED:
+ /* The server has disappeared! */
+ err = EIEIO;
+ break;
+
+ case KERN_NO_SPACE:
+ err = ENOMEM;
+ break;
+
+ case KERN_INVALID_ARGUMENT:
+ err = EINVAL;
+ break;
+
+ case 0:
+ return 0;
+
+ default:
+ break;
+ }
+
+ return -1;
+}
/* Basic ports and info, initialized by startup. */
diff --git a/include/unistd.h b/include/unistd.h
index d2802b2..6144f41 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -181,6 +181,12 @@ extern int __getlogin_r_loginuid (char *name, size_t namesize)
# include <dl-unistd.h>
# endif
+# if IS_IN (rtld) || !defined SHARED
+/* __access variant that does not set errno. Used in very early initialization
+ code in libc.a and ld.so. */
+extern __typeof (__access) __access_noerrno attribute_hidden;
+# endif
+
__END_DECLS
# endif
diff --git a/io/access.c b/io/access.c
index 4534704..859cf75 100644
--- a/io/access.c
+++ b/io/access.c
@@ -19,6 +19,13 @@
#include <stddef.h>
#include <unistd.h>
+/* Test for access to FILE without setting errno. */
+int
+__access_noerrno (const char *file, int type)
+{
+ return -1;
+}
+
/* Test for access to FILE. */
int
__access (const char *file, int type)
diff --git a/sysdeps/mach/hurd/access.c b/sysdeps/mach/hurd/access.c
index c308340..620acea 100644
--- a/sysdeps/mach/hurd/access.c
+++ b/sysdeps/mach/hurd/access.c
@@ -22,9 +22,20 @@
#include <hurd/lookup.h>
#include <fcntl.h>
-/* Test for access to FILE by our real user and group IDs. */
-int
-__access (const char *file, int type)
+static int
+hurd_fail_seterrno (error_t err)
+{
+ return __hurd_fail (err);
+}
+
+static int
+hurd_fail_noerrno (error_t err)
+{
+ return __hurd_fail_noerrno (err);
+}
+
+static int
+access_common (const char *file, int type, int (*errfunc) (error_t))
{
error_t err;
file_t rcrdir, rcwdir, io;
@@ -120,13 +131,13 @@ __access (const char *file, int type)
if (rcwdir != MACH_PORT_NULL)
__mach_port_deallocate (__mach_task_self (), rcwdir);
if (err)
- return __hurd_fail (err);
+ return errfunc (err);
/* Find out what types of access we are allowed to this file. */
err = __file_check_access (io, &allowed);
__mach_port_deallocate (__mach_task_self (), io);
if (err)
- return __hurd_fail (err);
+ return errfunc (err);
flags = 0;
if (type & R_OK)
@@ -138,9 +149,23 @@ __access (const char *file, int type)
if (flags & ~allowed)
/* We are not allowed all the requested types of access. */
- return __hurd_fail (EACCES);
+ return errfunc (EACESS);
return 0;
}
+/* Test for access to FILE by our real user and group IDs without setting
+ errno. */
+int
+__access_noerrno (const char *file, int type)
+{
+ return access_common (file, type, hurd_fail_noerrno);
+}
+
+/* Test for access to FILE by our real user and group IDs. */
+int
+__access (const char *file, int type)
+{
+ return access_common (file, type, hurd_fail);
+}
weak_alias (__access, access)
diff --git a/sysdeps/nacl/access.c b/sysdeps/nacl/access.c
index 95a0fb7..e07d558 100644
--- a/sysdeps/nacl/access.c
+++ b/sysdeps/nacl/access.c
@@ -19,6 +19,13 @@
#include <unistd.h>
#include <nacl-interfaces.h>
+/* Test for access to FILE without setting errno. */
+int
+__access_noerrno (const char *file, int type)
+{
+ return NACL_CALL_NOERRNO (__nacl_irt_dev_filename.access (file, type), 0);
+}
+
/* Test for access to FILE. */
int
__access (const char *file, int type)
diff --git a/sysdeps/nacl/nacl-interfaces.h b/sysdeps/nacl/nacl-interfaces.h
index b7b45bb..edd3217 100644
--- a/sysdeps/nacl/nacl-interfaces.h
+++ b/sysdeps/nacl/nacl-interfaces.h
@@ -113,4 +113,8 @@ __nacl_fail (int err)
#define NACL_CALL(err, val) \
({ int _err = (err); _err ? __nacl_fail (_err) : (val); })
+/* Same as NACL_CALL but without setting errno. */
+#define NACL_CALL_NOERRNO(err, val) \
+ ({ int _err = (err); _err ? _err : (val); })
+
#endif /* nacl-interfaces.h */
diff --git a/sysdeps/unix/sysv/linux/access.c b/sysdeps/unix/sysv/linux/access.c
index 8f003df..adefbca 100644
--- a/sysdeps/unix/sysv/linux/access.c
+++ b/sysdeps/unix/sysv/linux/access.c
@@ -21,6 +21,21 @@
#include <sysdep-cancel.h>
int
+__access_noerrno (const char *file, int type)
+{
+ int res;
+ INTERNAL_SYSCALL_DECL (err);
+#ifdef __NR_access
+ res = INTERNAL_SYSCALL_CALL (access, err, file, type);
+#else
+ res = INTERNAL_SYSCALL_CALL (faccessat, err, AT_FDCWD, file, type);
+#endif
+ if (INTERNAL_SYSCALL_ERROR_P (res, err))
+ return INTERNAL_SYSCALL_ERRNO (res, err);
+ return 0;
+}
+
+int
__access (const char *file, int type)
{
#ifdef __NR_access
--
2.7.4