Michael Kerrisk suggested to replace numeric clock IDs on symbolic
names.
Now the content of these files looks like this:
$ cat /proc/5362/timens_offsets
monotonic 9504000 0
boottime 3456000 0
For setting offsets, both representations of clocks can be used.
As for compatibility, it is acceptable to change things as long as
userspace doesn't care. The format of timens_offsets files is very
new and there are no userspace tools that rely on this format.
But three projects crun, util-linux and criu rely on the interface of
setting time offsets and this is why we need to continue supporting the
clock IDs in this case.
Fixes: 04a8682a71be ("fs/proc: Introduce /proc/pid/timens_offsets")
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Cc: Dmitry Safonov <0x7f454c46@xxxxxxxxx>
Suggested-by: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Signed-off-by: Andrei Vagin <avagin@xxxxxxxxx>
---
fs/proc/base.c | 14 +++++++++++++-
kernel/time/namespace.c | 15 ++++++++++++++-
2 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 6042b646ab27..572898dd16a0 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1573,6 +1573,7 @@ static ssize_t timens_offsets_write(struct file *file, const char __user *buf,
noffsets = 0;
for (pos = kbuf; pos; pos = next_line) {
struct proc_timens_offset *off = &offsets[noffsets];
+ char clock[10];
int err;
/* Find the end of line and ensure we don't look past it */
@@ -1584,10 +1585,21 @@ static ssize_t timens_offsets_write(struct file *file, const char __user *buf,
next_line = NULL;
}
- err = sscanf(pos, "%u %lld %lu", &off->clockid,
+ err = sscanf(pos, "%9s %lld %lu", clock,
&off->val.tv_sec, &off->val.tv_nsec);
if (err != 3 || off->val.tv_nsec >= NSEC_PER_SEC)
goto out;
+
+ clock[sizeof(clock) - 1] = 0;
+ if (strcmp(clock, "monotonic") == 0 ||
+ strcmp(clock, __stringify(CLOCK_MONOTONIC)) == 0)
+ off->clockid = CLOCK_MONOTONIC;
+ else if (strcmp(clock, "boottime") == 0 ||
+ strcmp(clock, __stringify(CLOCK_BOOTTIME)) == 0)
+ off->clockid = CLOCK_BOOTTIME;
+ else
+ goto out;
+
noffsets++;
if (noffsets == ARRAY_SIZE(offsets)) {
if (next_line)
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index e6ba064ce773..8127d2647064 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -338,7 +338,20 @@ static struct user_namespace *timens_owner(struct ns_common *ns)
static void show_offset(struct seq_file *m, int clockid, struct timespec64 *ts)
{
- seq_printf(m, "%d %lld %ld\n", clockid, ts->tv_sec, ts->tv_nsec);
+ char *clock;
+
+ switch (clockid) {
+ case CLOCK_BOOTTIME:
+ clock = "boottime";
+ break;
+ case CLOCK_MONOTONIC:
+ clock = "monotonic";
+ break;
+ default:
+ clock = "unknown";
+ break;
+ }
+ seq_printf(m, "%s\t%10lld\t%10ld\n", clock, ts->tv_sec, ts->tv_nsec);
}
void proc_timens_show_offsets(struct task_struct *p, struct seq_file *m)
--
2.24.1
