OK thanks. Let's pursue this further on this ticket:
https://gitlab.haskell.org/ghc/ghc/-/issues/19525
Simon
| -----Original Message-----
| From: ghc-devs On Behalf Of Viktor
| Dukhovni
| Sent: 11 March 2021 20:36
| To: ghc-devs@haskell.org
| Subject: Re: WSL2
|
| On Thu, Mar 11, 2021 at 07:53:20PM +0000, Simon Peyton Jones via ghc-
| devs wrote:
|
| > Voila
|
| Thanks!
|
| > /etc/nsswitch.conf group entry
| > group: files systemd
|
| The main "suspicious" thing here (decoded traces below my signature)
| is that the nsswitch.conf file is configured to try "systemd" as a
| source of group data, but attempts to contact "systemd" or read the
| underlying systemd store directly are failing. This is different from
| "not found", where systemd might have furnished a negative reply (as
| is the case on my Fedora 31 system, see below).
|
| So a failure return code is not surprising, because the answer is not
| authoritative, systemd might have answered differently if it had been
| possible to query it. It appears the WSL2 systems have a systemically
| misconfigured "nsswitch.conf" that wants to query "group" (and likely
| other) data from an unavailable source.
|
| [ Bottom line, the "unix" test case in question may need to be
| prepared
| to encounter such misconfiguration of the test platform and accept
| either type of error. Perhaps catch the IO expected IO exception,
| and
| output a fixed "not found" message regardless of the exception
| details,
| or by specifically checking for either of the two expected forms. ]
|
| By way of contrast, on my Fedora system, systemd can actually be
| reached and appears to respond to the "nss" library's satisfaction:
|
| execve("/usr/bin/getent", ["getent", "group", "xyzzy0"],
| 0x7fff3afbcca0 /* 31 vars */) = 0
| ...
| openat(AT_FDCWD, "/lib64/libnss_files.so.2", O_RDONLY|O_CLOEXEC) =
| 3
| openat(AT_FDCWD, "/etc/group", O_RDONLY|O_CLOEXEC) = 3
| read(3, "root:x:0:\nbin:x:1:\ndaemon:x:2:\ns"..., 4096) = 1161
| read(3, "", 4096) = 0
| ...
| openat(AT_FDCWD, "/lib64/libnss_systemd.so.2", O_RDONLY|O_CLOEXEC)
| = 3
| access("/etc/systemd/dont-synthesize-nobody", F_OK) = -1 ENOENT
| (No such file or directory)
| socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0) = 3
| connect(3, {sa_family=AF_UNIX,
| sun_path="/run/dbus/system_bus_socket"}, 30) = 0
| getsockopt(3, SOL_SOCKET, SO_PEERCRED, {pid=1, uid=0, gid=0},
| [12]) = 0
| getsockopt(3, SOL_SOCKET, SO_PEERSEC, 0x5568c64660e0, [64]) = -1
| ENOPROTOOPT (Protocol not available)
| getsockopt(3, SOL_SOCKET, SO_PEERGROUPS, 0x5568c6466130, [256->0])
| = 0
| sendmsg(3, {msg_name=NULL, msg_namelen=0,
| msg_iov=[{iov_base="\0AUTH EXTERNAL\r\nDATA\r\n", iov_len=22},
| {iov_base="NEGOTIATE_UNIX_FD\r\n", iov_len=19}, {iov_base="BEGIN\r\n",
| iov_len=7}], msg_iovlen=3, msg_controllen=0, msg_flags=0},
| MSG_DONTWAIT|MSG_NOSIGNAL) = 48
| recvmsg(3, {msg_name=NULL, msg_namelen=0,
| msg_iov=[{iov_base="DATA\r\nOK 7bc788e33c85b875f6b74a6"...,
| iov_len=256}], msg_iovlen=1, msg_controllen=0,
| msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_CMSG_CLOEXEC) = 58
| sendmsg(3, {msg_name=NULL, msg_namelen=0,
| msg_iov=[{iov_base="l\1\0\1\0\0\0\0\1\0\0\0m\0\0\0\1\1o\0\25\0\0\0/org
| /fre"..., iov_len=128}], msg_iovlen=1, msg_controllen=0, msg_flags=0},
| MSG_DONTWAIT|MSG_NOSIGNAL) = 128
| recvmsg(3, {msg_name=NULL, msg_namelen=0,
| msg_iov=[{iov_base="l\2\1\1\16\0\0\0\377\377\377\377G\0\0\0\5\1u\0\1\0
| \0\0", iov_len=24}], msg_iovlen=1, msg_controllen=0,
| msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_CMSG_CLOEXEC) = 24
| recvmsg(3, {msg_name=NULL, msg_namelen=0,
| msg_iov=[{iov_base="\7\1s\0\24\0\0\0org.freedesktop.DBus\0\0\0\0"...,
| iov_len=78}], msg_iovlen=1, msg_controllen=0,
| msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_CMSG_CLOEXEC) = 78
| sendmsg(3, {msg_name=NULL, msg_namelen=0,
| msg_iov=[{iov_base="l\1\0\1\v\0\0\0\2\0\0\0\247\0\0\0\1\1o\0\31\0\0\0/
| org/fre"..., iov_len=184}, {iov_base="\6\0\0\0xyzzy0\0", iov_len=11}],
| msg_iovlen=2, msg_controllen=0, msg_flags=0},
| MSG_DONTWAIT|MSG_NOSIGNAL) = 195
| recvmsg(3, {msg_name=NULL, msg_namelen=0,
| msg_iov=[{iov_base="l\4\1\1\16\0\0\0\377\377\377\377\227\0\0\0\7\1s\0\
| 24\0\0\0", iov_len=24}], msg_iovlen=1, msg_controllen=0,
| msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_CMSG_CLOEXEC) = 24
| recvmsg(3, {msg_name=NULL, msg_namelen=0,
| msg_iov=[{iov_base="org.freedesktop.DBus\0\0\0\0\6\1s\0\t\0\0\0"...,
| iov_len=158}], msg_iovlen=1, msg_controllen=0,
| msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_CMSG_CLOEXEC) = 158
| recvmsg(3, {msg_name=NULL, msg_namelen=0,
| msg_iov=[{iov_base="l\3\1\1(\0\0\0\257\30\r\0m\0\0\0\5\1u\0\2\0\0\0",
| iov_len=24}], msg_iovlen=1, msg_controllen=0,
| msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_CMSG_CLOEXEC) = 24
| recvmsg(3, {msg_name=NULL, msg_namelen=0,
| msg_iov=[{iov_base="\6\1s\0\t\0\0\0:1.303526\0\0\0\0\0\0\0\4\1s\0*\0\0
| \0"..., iov_len=144}], msg_iovlen=1, msg_controllen=0,
| msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_CMSG_CLOEXEC) = 144
| close(3) = 0
|
| --
| Viktor.
|
| So group lookups are configured to try /etc/group first, and then some
| systemd-based machinery (possibly creating groups on the fly, ...).
|
| > == Tracing getent group xyzzy0
|
| execve("/usr/bin/getent", ["getent", "group", "xyzzy0"],
| 0x7ffeb59f7a30 /* 26 vars */) = 0
| brk(NULL) = 0x55cb17d10000
| ... [ initialisation ] ...
| openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libnss_files.so.2",
| O_RDONLY|O_CLOEXEC) = 3
| close(3) = 0
| ... [ loading code for "files" ] ...
| openat(AT_FDCWD, "/etc/group", O_RDONLY|O_CLOEXEC) = 3
| read(3, "root:x:0:\ndaemon:x:1:\nbin:x:2:\ns"..., 4096) = 828
| read(3, "", 4096) = 0
| ... [ no match in "/etc/group" ] ...
| openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libnss_systemd.so.2",
| O_RDONLY|O_CLOEXEC) = 3
| ... [ loading code for "systemd" ] ...
| socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0) = 3
| connect(3, {sa_family=AF_UNIX, sun_path=@"userdb-
| 16b836ad920fd3bea17e1fa40e9f2f3c"}, 42) = -1 ECONNREFUSED (Connection
| refused)
| close(3) = 0
| ... [ failing to connect to systemd socket ] ...
| openat(AT_FDCWD, "/run/systemd/userdb/",
| O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = -1 ENOENT (No such file
| or directory)
| ... [ failing to directly access the data ] ...
| exit_group(2) = ?
| ... [ "not found" exit status ] ...
|
| > == Tracing getgrnam xyzzy0
| > (null)((nil)) No such process(3)
| execve("./getgrnam", ["./getgrnam", "xyzzy0"], 0x7fff81dc1c38 /*
| 26 vars */) = 0
| ...
| openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libnss_files.so.2",
| O_RDONLY|O_CLOEXEC) = 3
| ...
| openat(AT_FDCWD, "/etc/group", O_RDONLY|O_CLOEXEC) = 3
| read(3, "root:x:0:\ndaemon:x:1:\nbin:x:2:\ns"..., 4096) = 828
| read(3, "", 4096) = 0
| ...
| openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libnss_systemd.so.2",
| O_RDONLY|O_CLOEXEC) = 3
| socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0) = 3
| connect(3, {sa_family=AF_UNIX, sun_path=@"userdb-
| 2cecd700b3e3705ac56ef006755c59a9"}, 42) = -1 ECONNREFUSED (Connection
| refused)
| openat(AT_FDCWD, "/run/systemd/userdb/",
| O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = -1 ENOENT (No such file
| or directory)
| write(1, "(null)((nil)) No such process(3)"..., 33) = 33
| ... [ same as getent(1), errno is from user-land,
| otherwise would have been ENOENT, not ESRCH ]
|
| > == Tracing getent group root
| > root:x:0:
| execve("/usr/bin/getent", ["getent", "group", "root"],
| 0x7ffea01ff4f0 /* 26 vars */) = 0
| ...
| openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libnss_files.so.2",
| O_RDONLY|O_CLOEXEC) = 3
| ...
| openat(AT_FDCWD, "/etc/group", O_RDONLY|O_CLOEXEC) = 3
| read(3, "root:x:0:\ndaemon:x:1:\nbin:x:2:\ns"..., 4096) = 828
| write(1, "root:x:0:\n", 10) = 10
| ... [ found a match in /etc/group ] ...
| exit_group(0) = ?
| ... [ success exit ] ...
|
| > == Tracing getgrnam root
| > root(0x7ffc07bd1490) Success(0)
| execve("./getgrnam", ["./getgrnam", "root"], 0x7ffe5f593598 /* 26
| vars */) = 0
| openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libnss_files.so.2",
| O_RDONLY|O_CLOEXEC) = 3
| openat(AT_FDCWD, "/etc/group", O_RDONLY|O_CLOEXEC) = 3
| read(3, "root:x:0:\ndaemon:x:1:\nbin:x:2:\ns"..., 4096) = 828
| write(1, "root(0x7ffc07bd1490) Success(0)\n", 32) = 32
| exit_group(0) = ?
| ... [ ditto ] ...
| _______________________________________________
| ghc-devs mailing list
| ghc-devs@haskell.org
| https://nam06.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmail.
| haskell.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fghc-
| devs&data=04%7C01%7Csimonpj%40microsoft.com%7C45a66bb32c394418ea61
| 08d8e4cd6b23%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637510918226
| 583068%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJ
| BTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=hNJpeFwl8DTDXAyzfdfNFnawU
| YmQ3BnNqhlYgEMRxAM%3D&reserved=0
