From: Florian Weimer via Libc-alpha <libc-alpha@sourceware.org>
To: libc-alpha@sourceware.org
Subject: [PATCH] Linux: Use faccessat2 to implement faccessat (bug 18683)
Date: Fri, 07 Aug 2020 18:58:30 +0200 [thread overview]
Message-ID: <877dual7ex.fsf@oldenburg2.str.redhat.com> (raw)
This provides correct AT_EACCESS handling and also takes
Linux security modules into account.
Tested on i686-linux-gnu, x86_64-linux-gnu. Built with
build-many-glibcs.py.
---
sysdeps/unix/sysv/linux/faccessat.c | 14 +++++++++++---
sysdeps/unix/sysv/linux/kernel-features.h | 8 ++++++++
2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/faccessat.c b/sysdeps/unix/sysv/linux/faccessat.c
index e4f18ab2db..56cb6dcc8b 100644
--- a/sysdeps/unix/sysv/linux/faccessat.c
+++ b/sysdeps/unix/sysv/linux/faccessat.c
@@ -30,6 +30,13 @@
int
faccessat (int fd, const char *file, int mode, int flag)
{
+ int ret = INLINE_SYSCALL_CALL (faccessat2, fd, file, mode, flag);
+#if __ASSUME_FACCESSAT2
+ return ret;
+#else
+ if (ret == 0 || errno != ENOSYS)
+ return ret;
+
if (flag & ~(AT_SYMLINK_NOFOLLOW | AT_EACCESS))
return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
@@ -41,9 +48,9 @@ faccessat (int fd, const char *file, int mode, int flag)
return -1;
mode &= (X_OK | W_OK | R_OK); /* Clear any bogus bits. */
-#if R_OK != S_IROTH || W_OK != S_IWOTH || X_OK != S_IXOTH
-# error Oops, portability assumptions incorrect.
-#endif
+# if R_OK != S_IROTH || W_OK != S_IWOTH || X_OK != S_IXOTH
+# error Oops, portability assumptions incorrect.
+# endif
if (mode == F_OK)
return 0; /* The file exists. */
@@ -68,4 +75,5 @@ faccessat (int fd, const char *file, int mode, int flag)
return 0;
return INLINE_SYSCALL_ERROR_RETURN_VALUE (EACCES);
+#endif /* !__ASSUME_FACCESSAT2 */
}
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index 32533e94cf..a6bbc3c94e 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -214,4 +214,12 @@
# define __ASSUME_WAITID_PID0_P_PGID
#endif
+/* The faccessat2 system call was introduced across all architectures
+ in Linux 5.8. */
+#if __LINUX_KERNEL_VERSION >= 0x050800
+# define __ASSUME_FACCESSAT2 1
+#else
+# define __ASSUME_FACCESSAT2 0
+#endif
+
#endif /* kernel-features.h */
next reply other threads:[~2020-08-07 16:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-07 16:58 Florian Weimer via Libc-alpha [this message]
2020-08-07 19:58 ` [PATCH] Linux: Use faccessat2 to implement faccessat (bug 18683) Adhemerval Zanella via Libc-alpha
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