| Message ID | 1a4df1b5638d73b64200add175be9d69013418d8.1608401453.git.alistair.francis@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v1,1/1] linux-user/signal: Decode waitid si_code | expand |
On Sat, Dec 19, 2020 at 10:11 AM Alistair Francis <alistair.francis@wdc.com> wrote: > > When mapping the host waitid status to the target status we previously > just used decoding information in the status value. This doesn't follow > what the waitid documentation describes, which instead suggests using > the si_code value for the decoding. This results in the incorrect values > seen when calling waitid. This is especially apparent on RV32 where all > wait calls use waitid (see the bug case). > > This patch uses the si_code value to map the waitid status. > > Buglink: https://bugs.launchpad.net/qemu/+bug/1906193 > Signed-off-by: Alistair Francis <alistair.francis@wdc.com> Ping! Alistair > --- > linux-user/signal.c | 26 ++++++++++++++++++++++++-- > 1 file changed, 24 insertions(+), 2 deletions(-) > > diff --git a/linux-user/signal.c b/linux-user/signal.c > index 73de934c65..b6c9326521 100644 > --- a/linux-user/signal.c > +++ b/linux-user/signal.c > @@ -305,6 +305,7 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, > int sig = host_to_target_signal(info->si_signo); > int si_code = info->si_code; > int si_type; > + int status = info->si_status; > tinfo->si_signo = sig; > tinfo->si_errno = 0; > tinfo->si_code = info->si_code; > @@ -349,8 +350,29 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, > case TARGET_SIGCHLD: > tinfo->_sifields._sigchld._pid = info->si_pid; > tinfo->_sifields._sigchld._uid = info->si_uid; > - tinfo->_sifields._sigchld._status > - = host_to_target_waitstatus(info->si_status); > + > + /* > + * Map host to target signal numbers for the waitid family of > + * syscalls. This is similar to the functionality in > + * host_to_target_waitstatus() except we use the si_code to > + * determine the operation. > + */ > + switch (info->si_code) { > + case CLD_KILLED: > + case CLD_DUMPED: > + tinfo->_sifields._sigchld._status = > + host_to_target_signal(WTERMSIG(status)) | > + (status & ~0x7f); > + break; > + case CLD_STOPPED: > + tinfo->_sifields._sigchld._status = > + (host_to_target_signal(WSTOPSIG(status)) << 8) | > + (status & 0xff); > + break; > + default: > + tinfo->_sifields._sigchld._status = status; > + } > + > tinfo->_sifields._sigchld._utime = info->si_utime; > tinfo->_sifields._sigchld._stime = info->si_stime; > si_type = QEMU_SI_CHLD; > -- > 2.29.2 >
Am Samstag, 19. Dezember 2020, 20:11:13 EET schrieb Alistair Francis: > When mapping the host waitid status to the target status we previously > just used decoding information in the status value. This doesn't follow > what the waitid documentation describes, which instead suggests using > the si_code value for the decoding. This results in the incorrect values > seen when calling waitid. This is especially apparent on RV32 where all > wait calls use waitid (see the bug case). > > This patch uses the si_code value to map the waitid status. > > Buglink: https://bugs.launchpad.net/qemu/+bug/1906193 > Signed-off-by: Alistair Francis <alistair.francis@wdc.com> Tested-by: Andreas K. Hüttel <dilfridge@gentoo.org> > --- > linux-user/signal.c | 26 ++++++++++++++++++++++++-- > 1 file changed, 24 insertions(+), 2 deletions(-) > > diff --git a/linux-user/signal.c b/linux-user/signal.c > index 73de934c65..b6c9326521 100644 > --- a/linux-user/signal.c > +++ b/linux-user/signal.c > @@ -305,6 +305,7 @@ static inline void > host_to_target_siginfo_noswap(target_siginfo_t *tinfo, int sig = > host_to_target_signal(info->si_signo); > int si_code = info->si_code; > int si_type; > + int status = info->si_status; > tinfo->si_signo = sig; > tinfo->si_errno = 0; > tinfo->si_code = info->si_code; > @@ -349,8 +350,29 @@ static inline void > host_to_target_siginfo_noswap(target_siginfo_t *tinfo, case TARGET_SIGCHLD: > tinfo->_sifields._sigchld._pid = info->si_pid; > tinfo->_sifields._sigchld._uid = info->si_uid; > - tinfo->_sifields._sigchld._status > - = host_to_target_waitstatus(info->si_status); > + > + /* > + * Map host to target signal numbers for the waitid family of > + * syscalls. This is similar to the functionality in > + * host_to_target_waitstatus() except we use the si_code to > + * determine the operation. > + */ > + switch (info->si_code) { > + case CLD_KILLED: > + case CLD_DUMPED: > + tinfo->_sifields._sigchld._status = > + host_to_target_signal(WTERMSIG(status)) | > + (status & ~0x7f); > + break; > + case CLD_STOPPED: > + tinfo->_sifields._sigchld._status = > + (host_to_target_signal(WSTOPSIG(status)) << 8) | > + (status & 0xff); > + break; > + default: > + tinfo->_sifields._sigchld._status = status; > + } > + > tinfo->_sifields._sigchld._utime = info->si_utime; > tinfo->_sifields._sigchld._stime = info->si_stime; > si_type = QEMU_SI_CHLD;
Le 19/12/2020 à 19:11, Alistair Francis a écrit : > When mapping the host waitid status to the target status we previously > just used decoding information in the status value. This doesn't follow > what the waitid documentation describes, which instead suggests using > the si_code value for the decoding. This results in the incorrect values > seen when calling waitid. This is especially apparent on RV32 where all > wait calls use waitid (see the bug case). > > This patch uses the si_code value to map the waitid status. > > Buglink: https://bugs.launchpad.net/qemu/+bug/1906193 > Signed-off-by: Alistair Francis <alistair.francis@wdc.com> > --- > linux-user/signal.c | 26 ++++++++++++++++++++++++-- > 1 file changed, 24 insertions(+), 2 deletions(-) > > diff --git a/linux-user/signal.c b/linux-user/signal.c > index 73de934c65..b6c9326521 100644 > --- a/linux-user/signal.c > +++ b/linux-user/signal.c > @@ -305,6 +305,7 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, > int sig = host_to_target_signal(info->si_signo); > int si_code = info->si_code; > int si_type; > + int status = info->si_status; > tinfo->si_signo = sig; > tinfo->si_errno = 0; > tinfo->si_code = info->si_code; > @@ -349,8 +350,29 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, > case TARGET_SIGCHLD: > tinfo->_sifields._sigchld._pid = info->si_pid; > tinfo->_sifields._sigchld._uid = info->si_uid; > - tinfo->_sifields._sigchld._status > - = host_to_target_waitstatus(info->si_status); > + > + /* > + * Map host to target signal numbers for the waitid family of > + * syscalls. This is similar to the functionality in > + * host_to_target_waitstatus() except we use the si_code to > + * determine the operation. > + */ > + switch (info->si_code) { > + case CLD_KILLED: > + case CLD_DUMPED: > + tinfo->_sifields._sigchld._status = > + host_to_target_signal(WTERMSIG(status)) | > + (status & ~0x7f); > + break; > + case CLD_STOPPED: > + tinfo->_sifields._sigchld._status = > + (host_to_target_signal(WSTOPSIG(status)) << 8) | > + (status & 0xff); > + break; > + default: I guess the the operation is not encoded in the status coming from the host as we need to use the si_code to decode the status, so why do we need to encode it in the status we send to the guest? Can it be only "tinfo->_sifields._sigchld._status = status" for all the cases? Thanks, Laurent
On Mon, Jan 18, 2021 at 6:36 AM Laurent Vivier <laurent@vivier.eu> wrote: > > Le 19/12/2020 à 19:11, Alistair Francis a écrit : > > When mapping the host waitid status to the target status we previously > > just used decoding information in the status value. This doesn't follow > > what the waitid documentation describes, which instead suggests using > > the si_code value for the decoding. This results in the incorrect values > > seen when calling waitid. This is especially apparent on RV32 where all > > wait calls use waitid (see the bug case). > > > > This patch uses the si_code value to map the waitid status. > > > > Buglink: https://bugs.launchpad.net/qemu/+bug/1906193 > > Signed-off-by: Alistair Francis <alistair.francis@wdc.com> > > --- > > linux-user/signal.c | 26 ++++++++++++++++++++++++-- > > 1 file changed, 24 insertions(+), 2 deletions(-) > > > > diff --git a/linux-user/signal.c b/linux-user/signal.c > > index 73de934c65..b6c9326521 100644 > > --- a/linux-user/signal.c > > +++ b/linux-user/signal.c > > @@ -305,6 +305,7 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, > > int sig = host_to_target_signal(info->si_signo); > > int si_code = info->si_code; > > int si_type; > > + int status = info->si_status; > > tinfo->si_signo = sig; > > tinfo->si_errno = 0; > > tinfo->si_code = info->si_code; > > @@ -349,8 +350,29 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, > > case TARGET_SIGCHLD: > > tinfo->_sifields._sigchld._pid = info->si_pid; > > tinfo->_sifields._sigchld._uid = info->si_uid; > > - tinfo->_sifields._sigchld._status > > - = host_to_target_waitstatus(info->si_status); > > + > > + /* > > + * Map host to target signal numbers for the waitid family of > > + * syscalls. This is similar to the functionality in > > + * host_to_target_waitstatus() except we use the si_code to > > + * determine the operation. > > + */ > > + switch (info->si_code) { > > + case CLD_KILLED: > > + case CLD_DUMPED: > > + tinfo->_sifields._sigchld._status = > > + host_to_target_signal(WTERMSIG(status)) | > > + (status & ~0x7f); > > + break; > > + case CLD_STOPPED: > > + tinfo->_sifields._sigchld._status = > > + (host_to_target_signal(WSTOPSIG(status)) << 8) | > > + (status & 0xff); > > + break; > > + default: > > I guess the the operation is not encoded in the status coming from the host as we need to use the > si_code to decode the status, so why do we need to encode it in the status we send to the guest? > > Can it be only "tinfo->_sifields._sigchld._status = status" for all the cases? That also works, I'll send a v2. Alistair > > Thanks, > Laurent
diff --git a/linux-user/signal.c b/linux-user/signal.c index 73de934c65..b6c9326521 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -305,6 +305,7 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, int sig = host_to_target_signal(info->si_signo); int si_code = info->si_code; int si_type; + int status = info->si_status; tinfo->si_signo = sig; tinfo->si_errno = 0; tinfo->si_code = info->si_code; @@ -349,8 +350,29 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, case TARGET_SIGCHLD: tinfo->_sifields._sigchld._pid = info->si_pid; tinfo->_sifields._sigchld._uid = info->si_uid; - tinfo->_sifields._sigchld._status - = host_to_target_waitstatus(info->si_status); + + /* + * Map host to target signal numbers for the waitid family of + * syscalls. This is similar to the functionality in + * host_to_target_waitstatus() except we use the si_code to + * determine the operation. + */ + switch (info->si_code) { + case CLD_KILLED: + case CLD_DUMPED: + tinfo->_sifields._sigchld._status = + host_to_target_signal(WTERMSIG(status)) | + (status & ~0x7f); + break; + case CLD_STOPPED: + tinfo->_sifields._sigchld._status = + (host_to_target_signal(WSTOPSIG(status)) << 8) | + (status & 0xff); + break; + default: + tinfo->_sifields._sigchld._status = status; + } + tinfo->_sifields._sigchld._utime = info->si_utime; tinfo->_sifields._sigchld._stime = info->si_stime; si_type = QEMU_SI_CHLD;
When mapping the host waitid status to the target status we previously just used decoding information in the status value. This doesn't follow what the waitid documentation describes, which instead suggests using the si_code value for the decoding. This results in the incorrect values seen when calling waitid. This is especially apparent on RV32 where all wait calls use waitid (see the bug case). This patch uses the si_code value to map the waitid status. Buglink: https://bugs.launchpad.net/qemu/+bug/1906193 Signed-off-by: Alistair Francis <alistair.francis@wdc.com> --- linux-user/signal.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-)