| Message ID | 20230707131928.89500-3-deller@gmx.de |
|---|---|
| State | New |
| Headers | show |
| Series | linux-user: Fix fcntl64() and accept4() for 32-bit targets | expand |
On 7/7/23 14:19, Helge Deller wrote: > The accept4() syscall takes two flags only: SOCK_NONBLOCK and > SOCK_CLOEXEC. > Even the real Linux kernel returns -EINVAL if any other bits > have been set. > > Change the implementation of accept4() to recognize those two values > only, instead of using the fcntl_flags_tbl[] bitmask translation. > > Beside this correction in behaviour, it actually fixes the accept4() > emulation for hppa, mips and alpha targets for which SOCK_NONBLOCK is > different than TARGET_SOCK_NONBLOCK. > > I noticed this wrong behaviour with the testcase of the debian lwt package > which failed (by timeout while hanging in the read() syscall) in qemu but > succeeded on real hardware. > > Signed-off-by: Helge Deller <deller@gmx.de> > --- > linux-user/syscall.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/linux-user/syscall.c b/linux-user/syscall.c > index 3f1e8e7ad9..9e9317237d 100644 > --- a/linux-user/syscall.c > +++ b/linux-user/syscall.c > @@ -3440,7 +3440,18 @@ static abi_long do_accept4(int fd, abi_ulong target_addr, > abi_long ret; > int host_flags; > > - host_flags = target_to_host_bitmask(flags, fcntl_flags_tbl); > + host_flags = 0; > +#if defined(SOCK_NONBLOCK) > + if (flags & ~(TARGET_SOCK_CLOEXEC | TARGET_SOCK_NONBLOCK)) { > + return -TARGET_EINVAL; > + } > + if (flags & TARGET_SOCK_NONBLOCK) { > + host_flags |= SOCK_NONBLOCK; > + } > +#endif Can we avoid the ifdef? Anyway, surely the TARGET bit check should not be protected by the #ifdef. r~
On 7/7/23 22:15, Richard Henderson wrote: > On 7/7/23 14:19, Helge Deller wrote: >> The accept4() syscall takes two flags only: SOCK_NONBLOCK and >> SOCK_CLOEXEC. >> Even the real Linux kernel returns -EINVAL if any other bits >> have been set. >> >> Change the implementation of accept4() to recognize those two values >> only, instead of using the fcntl_flags_tbl[] bitmask translation. >> >> Beside this correction in behaviour, it actually fixes the accept4() >> emulation for hppa, mips and alpha targets for which SOCK_NONBLOCK is >> different than TARGET_SOCK_NONBLOCK. >> >> I noticed this wrong behaviour with the testcase of the debian lwt package >> which failed (by timeout while hanging in the read() syscall) in qemu but >> succeeded on real hardware. >> >> Signed-off-by: Helge Deller <deller@gmx.de> >> --- >> linux-user/syscall.c | 13 ++++++++++++- >> 1 file changed, 12 insertions(+), 1 deletion(-) >> >> diff --git a/linux-user/syscall.c b/linux-user/syscall.c >> index 3f1e8e7ad9..9e9317237d 100644 >> --- a/linux-user/syscall.c >> +++ b/linux-user/syscall.c >> @@ -3440,7 +3440,18 @@ static abi_long do_accept4(int fd, abi_ulong target_addr, >> abi_long ret; >> int host_flags; >> >> - host_flags = target_to_host_bitmask(flags, fcntl_flags_tbl); >> + host_flags = 0; >> +#if defined(SOCK_NONBLOCK) >> + if (flags & ~(TARGET_SOCK_CLOEXEC | TARGET_SOCK_NONBLOCK)) { >> + return -TARGET_EINVAL; >> + } >> + if (flags & TARGET_SOCK_NONBLOCK) { >> + host_flags |= SOCK_NONBLOCK; >> + } >> +#endif > > Can we avoid the ifdef? I don't know. There are multiple such SOCK_NONBLOCK checks in the code. > Anyway, surely the TARGET bit check should not be protected by the #ifdef. Ok. Helge
diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 3f1e8e7ad9..9e9317237d 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -3440,7 +3440,18 @@ static abi_long do_accept4(int fd, abi_ulong target_addr, abi_long ret; int host_flags; - host_flags = target_to_host_bitmask(flags, fcntl_flags_tbl); + host_flags = 0; +#if defined(SOCK_NONBLOCK) + if (flags & ~(TARGET_SOCK_CLOEXEC | TARGET_SOCK_NONBLOCK)) { + return -TARGET_EINVAL; + } + if (flags & TARGET_SOCK_NONBLOCK) { + host_flags |= SOCK_NONBLOCK; + } +#endif + if (flags & TARGET_SOCK_CLOEXEC) { + host_flags |= SOCK_CLOEXEC; + } if (target_addr == 0) { return get_errno(safe_accept4(fd, NULL, NULL, host_flags));
The accept4() syscall takes two flags only: SOCK_NONBLOCK and SOCK_CLOEXEC. Even the real Linux kernel returns -EINVAL if any other bits have been set. Change the implementation of accept4() to recognize those two values only, instead of using the fcntl_flags_tbl[] bitmask translation. Beside this correction in behaviour, it actually fixes the accept4() emulation for hppa, mips and alpha targets for which SOCK_NONBLOCK is different than TARGET_SOCK_NONBLOCK. I noticed this wrong behaviour with the testcase of the debian lwt package which failed (by timeout while hanging in the read() syscall) in qemu but succeeded on real hardware. Signed-off-by: Helge Deller <deller@gmx.de> --- linux-user/syscall.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) -- 2.41.0