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authorArnd Bergmann <arnd@arndb.de>2018-04-17 09:11:58 +0200
committerArnd Bergmann <arnd@arndb.de>2018-08-29 15:42:23 +0200
commit185cfaf7641e14af85635bb2750da302e32b04e3 (patch)
tree2c9be980c5bef6c442529df090e5f5170196b4ce /fs/utimes.c
parenta4f7a3004630f1a0fb130ab1824942a49ce33140 (diff)
downloadlwn-185cfaf7641e14af85635bb2750da302e32b04e3.tar.gz
lwn-185cfaf7641e14af85635bb2750da302e32b04e3.zip
y2038: Compile utimes()/futimesat() conditionally
There are four generations of utimes() syscalls: utime(), utimes(), futimesat() and utimensat(), each one being a superset of the previous one. For y2038 support, we have to add another one, which is the same as the existing utimensat() but always passes 64-bit times_t based timespec values. There are currently 10 architectures that only use utimensat(), two that use utimes(), futimesat() and utimensat() but not utime(), and 11 architectures that have all four, and those define __ARCH_WANT_SYS_UTIME in order to get a sys_utime implementation. Since all the new architectures only want utimensat(), moving all the legacy entry points into a common __ARCH_WANT_SYS_UTIME guard simplifies the logic. Only alpha and ia64 grow a tiny bit as they now also get an unused sys_utime(), but it didn't seem worth the extra complexity of adding yet another ifdef for those. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'fs/utimes.c')
-rw-r--r--fs/utimes.c51
1 files changed, 22 insertions, 29 deletions
diff --git a/fs/utimes.c b/fs/utimes.c
index d30f409ecc1a..2f6f08061a26 100644
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -8,35 +8,6 @@
#include <linux/compat.h>
#include <asm/unistd.h>
-#ifdef __ARCH_WANT_SYS_UTIME
-
-/*
- * sys_utime() can be implemented in user-level using sys_utimes().
- * Is this for backwards compatibility? If so, why not move it
- * into the appropriate arch directory (for those architectures that
- * need it).
- */
-
-/* If times==NULL, set access and modification to current time,
- * must be owner or have write permission.
- * Else, update from *times, must be owner or super user.
- */
-SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
-{
- struct timespec64 tv[2];
-
- if (times) {
- if (get_user(tv[0].tv_sec, &times->actime) ||
- get_user(tv[1].tv_sec, &times->modtime))
- return -EFAULT;
- tv[0].tv_nsec = 0;
- tv[1].tv_nsec = 0;
- }
- return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
-}
-
-#endif
-
static bool nsec_valid(long nsec)
{
if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
@@ -184,6 +155,13 @@ SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
}
+#ifdef __ARCH_WANT_SYS_UTIME
+/*
+ * futimesat(), utimes() and utime() are older versions of utimensat()
+ * that are provided for compatibility with traditional C libraries.
+ * On modern architectures, we always use libc wrappers around
+ * utimensat() instead.
+ */
static long do_futimesat(int dfd, const char __user *filename,
struct timeval __user *utimes)
{
@@ -225,6 +203,21 @@ SYSCALL_DEFINE2(utimes, char __user *, filename,
return do_futimesat(AT_FDCWD, filename, utimes);
}
+SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
+{
+ struct timespec64 tv[2];
+
+ if (times) {
+ if (get_user(tv[0].tv_sec, &times->actime) ||
+ get_user(tv[1].tv_sec, &times->modtime))
+ return -EFAULT;
+ tv[0].tv_nsec = 0;
+ tv[1].tv_nsec = 0;
+ }
+ return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
+}
+#endif
+
#ifdef CONFIG_COMPAT
/*
* Not all architectures have sys_utime, so implement this in terms