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authorAndrei Vagin <avagin@gmail.com>2020-04-11 08:40:31 -0700
committerThomas Gleixner <tglx@linutronix.de>2020-04-16 12:10:54 +0200
commit94d440d618467806009c8edc70b094d64e12ee5a (patch)
tree400e92a597865e29a0875cc2015c7d3c94fd10d0 /fs/proc/base.c
parent8f3d9f354286745c751374f5f1fcafee6b3f3136 (diff)
downloadlinux-94d440d618467806009c8edc70b094d64e12ee5a.tar.bz2
proc, time/namespace: Show clock symbolic names in /proc/pid/timens_offsets
Michael Kerrisk suggested to replace numeric clock IDs with symbolic names. Now the content of these files looks like this: $ cat /proc/774/timens_offsets monotonic 864000 0 boottime 1728000 0 For setting offsets, both representations of clocks (numeric and symbolic) 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 yet which rely on this format. But three projects crun, util-linux and criu rely on the interface of setting time offsets and this is why it's required to continue supporting the numeric clock IDs on write. Fixes: 04a8682a71be ("fs/proc: Introduce /proc/pid/timens_offsets") Suggested-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200411154031.642557-1-avagin@gmail.com
Diffstat (limited to 'fs/proc/base.c')
-rw-r--r--fs/proc/base.c14
1 files changed, 13 insertions, 1 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)