Message ID | 1362130380-1895-3-git-send-email-lilei@linux.vnet.ibm.com |
---|---|
State | New |
Headers | show |
On 03/01/2013 02:33 AM, Lei Li wrote: > Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com> > --- > qga/commands-posix.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > qga/qapi-schema.json | 27 ++++++++++++++++++++++++++ > 2 files changed, 82 insertions(+) > > diff --git a/qga/commands-posix.c b/qga/commands-posix.c > index f159e25..e246a0d 100644 > --- a/qga/commands-posix.c > +++ b/qga/commands-posix.c > @@ -135,6 +135,61 @@ int64_t qmp_guest_get_time(Error **errp) > return time_ns; > } > > +void qmp_guest_set_time(int64_t time_ns, Error **errp) > +{ > + int ret; > + int status; > + pid_t pid; > + Error *local_err = NULL; > + struct timeval tv; > + > + /* year-2038 will overflow in case time_t is 32bit */ > + if ((sizeof(time_t) <= 4) && ((unsigned long) time_ns & (1ul << 31))) { Wrong. If 'unsigned long' and 'time_t' are both 32 bits, but time_ns is 0x1000000000000000, then the cast truncates to 0 and you don't report overflow. Conversely, if time_ns is 0x80000000, you report overflow, even though this value fits in 32-bit time_t after you do division from nanoseconds back to seconds. What you WANT is: if (time_ns / 1000000000 != (time_t)(time_ns / 1000000000)) { > + error_setg_errno(errp, errno, "Invalid time %ld for overflow", > + time_ns); That wording sounds awkward. Worse, errno is NOT set to anything sane, so you do NOT want error_setg_errno. And %ld is wrong for int64_t on 32-bit platforms. How about: error_setg(errp, "Time %" PRI64D " is too large", time_ns); > +++ b/qga/qapi-schema.json > @@ -99,6 +99,33 @@ > 'returns': 'int' } > > ## > +# @guest-set-time: > +# > +# Set guest time. > +# > +# Right now, when a guest is paused or migrated to a file s/Right now, when/When/ > +# then loaded from that file, the guest OS has no idea that > +# there was a big gap in the time. Depending on how long > +# the gap was, NTP might not be able to resynchronize the > +# guest. > +# > +# This command tries to set guest time based on the information > +# from host or an absolute value given by management app, and > +# set the Hardware Clock to the current System Time. This > +# will make it easier for a guest to resynchronize without > +# waiting for NTP. > +# > +# @time: time of nanoseconds, relative to the Epoch of > +# 1970-01-01 in UTC/GMT. drop '/GMT' > +# > +# Returns: Nothing on success. > +# > +# Since: 1.5 > +## > +{ 'command': 'guest-set-time', > + 'data': { 'time': 'int' } } > + > +## > # @GuestAgentCommandInfo: > # > # Information about guest agent commands. >
On 03/01/2013 10:38 AM, Eric Blake wrote: >> + error_setg_errno(errp, errno, "Invalid time %ld for overflow", >> + time_ns); > > That wording sounds awkward. Worse, errno is NOT set to anything sane, > so you do NOT want error_setg_errno. And %ld is wrong for int64_t on > 32-bit platforms. How about: > > error_setg(errp, "Time %" PRI64D " is too large", time_ns); Don't know what I was thinking; there is no PRI64D. I meant PRId64.
On 03/02/2013 01:38 AM, Eric Blake wrote: > On 03/01/2013 02:33 AM, Lei Li wrote: >> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com> >> --- >> qga/commands-posix.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++ >> qga/qapi-schema.json | 27 ++++++++++++++++++++++++++ >> 2 files changed, 82 insertions(+) >> >> diff --git a/qga/commands-posix.c b/qga/commands-posix.c >> index f159e25..e246a0d 100644 >> --- a/qga/commands-posix.c >> +++ b/qga/commands-posix.c >> @@ -135,6 +135,61 @@ int64_t qmp_guest_get_time(Error **errp) >> return time_ns; >> } >> >> +void qmp_guest_set_time(int64_t time_ns, Error **errp) >> +{ >> + int ret; >> + int status; >> + pid_t pid; >> + Error *local_err = NULL; >> + struct timeval tv; >> + >> + /* year-2038 will overflow in case time_t is 32bit */ >> + if ((sizeof(time_t) <= 4) && ((unsigned long) time_ns & (1ul << 31))) { > Wrong. If 'unsigned long' and 'time_t' are both 32 bits, but time_ns is > 0x1000000000000000, then the cast truncates to 0 and you don't report > overflow. Conversely, if time_ns is 0x80000000, you report overflow, > even though this value fits in 32-bit time_t after you do division from > nanoseconds back to seconds. What you WANT is: Yes, you are right.. thanks. > > if (time_ns / 1000000000 != (time_t)(time_ns / 1000000000)) { > >> + error_setg_errno(errp, errno, "Invalid time %ld for overflow", >> + time_ns); > That wording sounds awkward. Worse, errno is NOT set to anything sane, > so you do NOT want error_setg_errno. And %ld is wrong for int64_t on > 32-bit platforms. How about: > > error_setg(errp, "Time %" PRI64D " is too large", time_ns); Sure, will address it as the your later reply. >> +++ b/qga/qapi-schema.json >> @@ -99,6 +99,33 @@ >> 'returns': 'int' } >> >> ## >> +# @guest-set-time: >> +# >> +# Set guest time. >> +# >> +# Right now, when a guest is paused or migrated to a file > s/Right now, when/When/ > >> +# then loaded from that file, the guest OS has no idea that >> +# there was a big gap in the time. Depending on how long >> +# the gap was, NTP might not be able to resynchronize the >> +# guest. >> +# >> +# This command tries to set guest time based on the information >> +# from host or an absolute value given by management app, and >> +# set the Hardware Clock to the current System Time. This >> +# will make it easier for a guest to resynchronize without >> +# waiting for NTP. >> +# >> +# @time: time of nanoseconds, relative to the Epoch of >> +# 1970-01-01 in UTC/GMT. > drop '/GMT' > >> +# >> +# Returns: Nothing on success. >> +# >> +# Since: 1.5 >> +## >> +{ 'command': 'guest-set-time', >> + 'data': { 'time': 'int' } } >> + >> +## >> # @GuestAgentCommandInfo: >> # >> # Information about guest agent commands. >>
diff --git a/qga/commands-posix.c b/qga/commands-posix.c index f159e25..e246a0d 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -135,6 +135,61 @@ int64_t qmp_guest_get_time(Error **errp) return time_ns; } +void qmp_guest_set_time(int64_t time_ns, Error **errp) +{ + int ret; + int status; + pid_t pid; + Error *local_err = NULL; + struct timeval tv; + + /* year-2038 will overflow in case time_t is 32bit */ + if ((sizeof(time_t) <= 4) && ((unsigned long) time_ns & (1ul << 31))) { + error_setg_errno(errp, errno, "Invalid time %ld for overflow", + time_ns); + } + + tv.tv_sec = time_ns / 1000000000; + tv.tv_usec = (time_ns % 1000000000) / 1000; + + ret = settimeofday(&tv, NULL); + if (ret < 0) { + error_setg_errno(errp, errno, "Failed to set time to guest"); + return; + } + + /* Set the Hardware Clock to the current System Time. */ + pid = fork(); + if (pid == 0) { + setsid(); + reopen_fd_to_null(0); + reopen_fd_to_null(1); + reopen_fd_to_null(2); + + execle("/sbin/hwclock", "hwclock", "-w", NULL, environ); + _exit(EXIT_FAILURE); + } else if (pid < 0) { + error_setg_errno(errp, errno, "failed to create child process"); + return; + } + + ga_wait_child(pid, &status, &local_err); + if (error_is_set(&local_err)) { + error_propagate(errp, local_err); + return; + } + + if (!WIFEXITED(status)) { + error_setg(errp, "child process has terminated abnormally"); + return; + } + + if (WEXITSTATUS(status)) { + error_setg(errp, "hwclock failed to set hardware clock to system time"); + return; + } +} + typedef struct GuestFileHandle { uint64_t id; FILE *fh; diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json index 563600c..5eba324 100644 --- a/qga/qapi-schema.json +++ b/qga/qapi-schema.json @@ -99,6 +99,33 @@ 'returns': 'int' } ## +# @guest-set-time: +# +# Set guest time. +# +# Right now, when a guest is paused or migrated to a file +# then loaded from that file, the guest OS has no idea that +# there was a big gap in the time. Depending on how long +# the gap was, NTP might not be able to resynchronize the +# guest. +# +# This command tries to set guest time based on the information +# from host or an absolute value given by management app, and +# set the Hardware Clock to the current System Time. This +# will make it easier for a guest to resynchronize without +# waiting for NTP. +# +# @time: time of nanoseconds, relative to the Epoch of +# 1970-01-01 in UTC/GMT. +# +# Returns: Nothing on success. +# +# Since: 1.5 +## +{ 'command': 'guest-set-time', + 'data': { 'time': 'int' } } + +## # @GuestAgentCommandInfo: # # Information about guest agent commands.
Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com> --- qga/commands-posix.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++ qga/qapi-schema.json | 27 ++++++++++++++++++++++++++ 2 files changed, 82 insertions(+)