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umockdev breaks due to systemd changes #69

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gicmo opened this issue Jan 20, 2018 · 0 comments
Closed

umockdev breaks due to systemd changes #69

gicmo opened this issue Jan 20, 2018 · 0 comments

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@gicmo
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gicmo commented Jan 20, 2018

As seen in fwupd/fwupd#370 (and also boltd ci).

$ LD_PRELOAD='libumockdev-preload.so.0' build/plugins/thunderbolt/thunderbolt-self-test -p /thunderbolt/basic

/thunderbolt/basic: 
ERROR: uevent_sender_send: No such device /sys/devices/domain0
ERROR: uevent_sender_send: No such device /sys/devices/domain0/0-0

When stracing you see a change in the syscall pattern:

working (systemd-234-9.fc27):

stat("/tmp", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=1400, ...}) = 0
access("/tmp/umockdev.TU2FDZ", F_OK)    = 0
stat("/tmp/umockdev.TU2FDZ", {st_mode=S_IFDIR|0700, st_size=80, ...}) = 0
access("/tmp/umockdev.TU2FDZ/sys", F_OK) = 0
stat("/tmp/umockdev.TU2FDZ/sys", {st_mode=S_IFDIR|0755, st_size=40, ...}) = 0
access("/tmp/umockdev.TU2FDZ/sys/devices", F_OK) = -1 ENOENT (No such file or directory)
mkdir("/tmp/umockdev.TU2FDZ/sys/devices", 0755) = 0
access("/tmp/umockdev.TU2FDZ/sys/devices/domain0", F_OK) = -1 ENOENT (No such file or directory)
mkdir("/tmp/umockdev.TU2FDZ/sys/devices/domain0", 0755) = 0
access("/tmp", F_OK)                    = 0
stat("/tmp", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=1400, ...}) = 0
access("/tmp/umockdev.TU2FDZ", F_OK)    = 0
stat("/tmp/umockdev.TU2FDZ", {st_mode=S_IFDIR|0700, st_size=80, ...}) = 0
access("/tmp/umockdev.TU2FDZ/sys", F_OK) = 0
stat("/tmp/umockdev.TU2FDZ/sys", {st_mode=S_IFDIR|0755, st_size=60, ...}) = 0
access("/tmp/umockdev.TU2FDZ/sys/class", F_OK) = -1 ENOENT (No such file or directory)
mkdir("/tmp/umockdev.TU2FDZ/sys/class", 0755) = 0
access("/tmp/umockdev.TU2FDZ/sys/class/thunderbolt", F_OK) = -1 ENOENT (No such file or directory)
mkdir("/tmp/umockdev.TU2FDZ/sys/class/thunderbolt", 0755) = 0
symlink("../../class/thunderbolt", "/tmp/umockdev.TU2FDZ/sys/devices/domain0/subsystem") = 0
symlink("../../devices/domain0", "/tmp/umockdev.TU2FDZ/sys/class/thunderbolt/domain0") = 0
openat(AT_FDCWD, "/tmp/umockdev.TU2FDZ/sys/devices/domain0/uevent.LD4FDZ", O_RDWR|O_CREAT|O_EXCL, 0666) = 5
fstat(5, {st_mode=S_IFREG|0664, st_size=0, ...}) = 0
fallocate(5, 0, 0, 27)                  = 0
write(5, "DEVTYPE=thunderbolt_domain\n", 27) = 27
fstatfs(5, {f_type=TMPFS_MAGIC, f_bsize=4096, f_blocks=2038207, f_bfree=2016916, f_bavail=2016916, f_files=2038207, f_ffree=2037878, f_fsid={val=[0, 0]}, f_namelen=255, f_frsize=4096, f_flags=ST_VALID|ST_NOSUID|ST_NODEV}) = 0
lstat("/tmp/umockdev.TU2FDZ/sys/devices/domain0/uevent", 0x7ffd6ab09030) = -1 ENOENT (No such file or directory)
close(5)                                = 0
rename("/tmp/umockdev.TU2FDZ/sys/devices/domain0/uevent.LD4FDZ", "/tmp/umockdev.TU2FDZ/sys/devices/domain0/uevent") = 0
openat(AT_FDCWD, "/tmp/umockdev.TU2FDZ/sys/devices/domain0/security.4Y4FDZ", O_RDWR|O_CREAT|O_EXCL, 0666) = 5
fstat(5, {st_mode=S_IFREG|0664, st_size=0, ...}) = 0
fallocate(5, 0, 0, 6)                   = 0
write(5, "secure", 6)                   = 6
fstatfs(5, {f_type=TMPFS_MAGIC, f_bsize=4096, f_blocks=2038207, f_bfree=2016915, f_bavail=2016915, f_files=2038207, f_ffree=2037877, f_fsid={val=[0, 0]}, f_namelen=255, f_frsize=4096, f_flags=ST_VALID|ST_NOSUID|ST_NODEV}) = 0
lstat("/tmp/umockdev.TU2FDZ/sys/devices/domain0/security", 0x7ffd6ab09030) = -1 ENOENT (No such file or directory)
close(5)                                = 0
rename("/tmp/umockdev.TU2FDZ/sys/devices/domain0/security.4Y4FDZ", "/tmp/umockdev.TU2FDZ/sys/devices/domain0/security") = 0
# [CK] setup done here
access("/tmp/umockdev.TU2FDZ/disabled", F_OK) = -1 ENOENT (No such file or directory)
readlinkat(AT_FDCWD, "/tmp/umockdev.TU2FDZ/sys/devices/domain0", 0x1ccb7d0, 99) = -1 EINVAL (Invalid argument)
access("/tmp/umockdev.TU2FDZ/disabled", F_OK) = -1 ENOENT (No such file or directory)
lstat("/tmp", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=1400, ...}) = 0
lstat("/tmp/umockdev.TU2FDZ", {st_mode=S_IFDIR|0700, st_size=80, ...}) = 0
lstat("/tmp/umockdev.TU2FDZ/sys", {st_mode=S_IFDIR|0755, st_size=80, ...}) = 0
lstat("/tmp/umockdev.TU2FDZ/sys/devices", {st_mode=S_IFDIR|0755, st_size=60, ...}) = 0
lstat("/tmp/umockdev.TU2FDZ/sys/devices/domain0", {st_mode=S_IFDIR|0755, st_size=100, ...}) = 0
access("/tmp/umockdev.TU2FDZ/disabled", F_OK) = -1 ENOENT (No such file or directory)
access("/tmp/umockdev.TU2FDZ/sys/devices/domain0/uevent", F_OK) = 0
access("/tmp/umockdev.TU2FDZ/disabled", F_OK) = -1 ENOENT (No such file or directory)
readlinkat(AT_FDCWD, "/tmp/umockdev.TU2FDZ/sys/devices/domain0/subsystem", "../../class/thunderbolt", 99) = 23
getrandom("\x70\x23\x74\xca\xfe\x46\x99\x38\xea\xdc\x52\x63\x53\x82\x02\x2d", 16, GRND_NONBLOCK) = 16
access("/tmp/umockdev.TU2FDZ/disabled", F_OK) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/tmp/umockdev.TU2FDZ/sys/devices/domain0/uevent", O_RDONLY|O_CLOEXEC) = 5
fstat(5, {st_mode=S_IFREG|0664, st_size=27, ...}) = 0
fstat(5, {st_mode=S_IFREG|0664, st_size=27, ...}) = 0
read(5, "DEVTYPE=thunderbolt_domain\n", 4096) = 27
read(5, "", 4096)                       = 0
close(5)                                = 0

not working:

stat("/tmp", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=1140, ...}) = 0
access("/tmp/umockdev.19EKDZ", F_OK)    = 0
stat("/tmp/umockdev.19EKDZ", {st_mode=S_IFDIR|0700, st_size=80, ...}) = 0
access("/tmp/umockdev.19EKDZ/sys", F_OK) = 0
stat("/tmp/umockdev.19EKDZ/sys", {st_mode=S_IFDIR|0755, st_size=40, ...}) = 0
access("/tmp/umockdev.19EKDZ/sys/devices", F_OK) = -1 ENOENT (No such file or directory)
mkdir("/tmp/umockdev.19EKDZ/sys/devices", 0755) = 0
access("/tmp/umockdev.19EKDZ/sys/devices/domain0", F_OK) = -1 ENOENT (No such file or directory)
mkdir("/tmp/umockdev.19EKDZ/sys/devices/domain0", 0755) = 0
access("/tmp", F_OK)                    = 0
stat("/tmp", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=1140, ...}) = 0
access("/tmp/umockdev.19EKDZ", F_OK)    = 0
stat("/tmp/umockdev.19EKDZ", {st_mode=S_IFDIR|0700, st_size=80, ...}) = 0
access("/tmp/umockdev.19EKDZ/sys", F_OK) = 0
stat("/tmp/umockdev.19EKDZ/sys", {st_mode=S_IFDIR|0755, st_size=60, ...}) = 0
access("/tmp/umockdev.19EKDZ/sys/bus", F_OK) = -1 ENOENT (No such file or directory)
mkdir("/tmp/umockdev.19EKDZ/sys/bus", 0755) = 0
access("/tmp/umockdev.19EKDZ/sys/bus/thunderbolt", F_OK) = -1 ENOENT (No such file or directory)
mkdir("/tmp/umockdev.19EKDZ/sys/bus/thunderbolt", 0755) = 0
access("/tmp/umockdev.19EKDZ/sys/bus/thunderbolt/devices", F_OK) = -1 ENOENT (No such file or directory)
mkdir("/tmp/umockdev.19EKDZ/sys/bus/thunderbolt/devices", 0755) = 0
symlink("../../../devices/domain0", "/tmp/umockdev.19EKDZ/sys/bus/thunderbolt/devices/domain0") = 0
symlink("../../bus/thunderbolt", "/tmp/umockdev.19EKDZ/sys/devices/domain0/subsystem") = 0
openat(AT_FDCWD, "/tmp/umockdev.19EKDZ/sys/devices/domain0/uevent.73ILDZ", O_RDWR|O_CREAT|O_EXCL, 0666) = 5
fstat(5, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
fallocate(5, 0, 0, 27)                  = 0
write(5, "DEVTYPE=thunderbolt_domain\n", 27) = 27
fstatfs(5, {f_type=TMPFS_MAGIC, f_bsize=4096, f_blocks=2049628, f_bfree=2045039, f_bavail=2045039, f_files=2049628, f_ffree=2048717, f_fsid={val=[0, 0]}, f_namelen=255, f_frsize=4096, f_flags=ST_VALID|ST_NOSUID|ST_NODEV}) = 0
lstat("/tmp/umockdev.19EKDZ/sys/devices/domain0/uevent", 0x7fff8a9cb810) = -1 ENOENT (No such file or directory)
close(5)                                = 0
rename("/tmp/umockdev.19EKDZ/sys/devices/domain0/uevent.73ILDZ", "/tmp/umockdev.19EKDZ/sys/devices/domain0/uevent") = 0
openat(AT_FDCWD, "/tmp/umockdev.19EKDZ/sys/devices/domain0/security.FEJLDZ", O_RDWR|O_CREAT|O_EXCL, 0666) = 5
fstat(5, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
fallocate(5, 0, 0, 6)                   = 0
write(5, "secure", 6)                   = 6
fstatfs(5, {f_type=TMPFS_MAGIC, f_bsize=4096, f_blocks=2049628, f_bfree=2045038, f_bavail=2045038, f_files=2049628, f_ffree=2048716, f_fsid={val=[0, 0]}, f_namelen=255, f_frsize=4096, f_flags=ST_VALID|ST_NOSUID|ST_NODEV}) = 0
lstat("/tmp/umockdev.19EKDZ/sys/devices/domain0/security", 0x7fff8a9cb810) = -1 ENOENT (No such file or directory)
close(5)                                = 0
rename("/tmp/umockdev.19EKDZ/sys/devices/domain0/security.FEJLDZ", "/tmp/umockdev.19EKDZ/sys/devices/domain0/security") = 0

setup done here is practically identical to working condition

openat(AT_FDCWD, "/", O_RDONLY|O_NOFOLLOW|O_CLOEXEC|O_PATH) = 5
fstat(5, {st_mode=S_IFDIR|0755, st_size=122, ...}) = 0
openat(5, "sys", O_RDONLY|O_NOFOLLOW|O_CLOEXEC|O_PATH) = 6
fstat(6, {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0
close(5)                                = 0
openat(6, "devices", O_RDONLY|O_NOFOLLOW|O_CLOEXEC|O_PATH) = 5
fstat(5, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
close(6)                                = 0
openat(5, "domain0", O_RDONLY|O_NOFOLLOW|O_CLOEXEC|O_PATH) = -1 ENOENT (No such file or directory)
close(5)                                = 0
write(2, "ERROR: uevent_sender_send: No su"..., 63ERROR: uevent_sender_send: No such device /sys/devices/domain0
) = 63

I suspect the culprit is chase_symlinks which uses openat on each path component and we are not catching those (yet).
I stepped through both processes in the debugger. The critical function is device_set_syspath in src/libsystemd/sd-device/sd-device.c.
In the working condition we get a call r = readlink_and_canonicalize(_syspath, NULL, &syspath); which returns -EINVAL and we get to canonicalize_file_name and all is well.
In the non-working condition (newer systemd) we get r = chase_symlinks(_syspath, NULL, 0, &syspath); returning -ENOENT and thus device_set_syspath returning -ENODEV.
The breaking change I guess is systemd/systemd-stable@d0467ba (as also found by @ArchangeGabriel in the fwup issue).
@gicmo gicmo mentioned this issue Jan 21, 2018
Merged
gicmo added a commit to gicmo/bolt that referenced this issue Jan 25, 2018
@gicmo
travis: disable 'arch' for now, (broken umockdev)
c79a390 
See martinpitt/umockdev#69
gicmo added a commit to gicmo/bolt that referenced this issue Jan 29, 2018
@gicmo
travis: disable 'arch' for now, (broken umockdev)
34e6a6d 
See martinpitt/umockdev#69
martinpitt added a commit that referenced this issue Feb 9, 2018
@martinpitt
Run tests on multiple Ubuntu releases
275d718 
Ubuntu 14.04 is becoming too old, and misses changes and breakage from
newer system libraries, like issue #69.

Move to building and testing in Launchpad buildd chroots for a given
Ubuntu release and architecture. Add Travis configuration to use this
for the current LTS, the current stable, and the current devel series.
@martinpitt martinpitt mentioned this issue Feb 9, 2018
Merged
martinpitt added a commit that referenced this issue Feb 9, 2018
@martinpitt
Run tests on multiple Ubuntu releases (#71)
e89681e 
Ubuntu 14.04 is becoming too old, and misses changes and breakage from
newer system libraries, like issue #69.

Move to building and testing in Launchpad buildd chroots for a given
Ubuntu release and architecture. Add Travis configuration to use this
for the current LTS, the current stable, and the current devel series.
martinpitt added a commit that referenced this issue Feb 9, 2018
@martinpitt
Provide an option to run tests with -proposed enabled
4afca56 
This reproduces #69. Don't enable it for CI as this is too unreliable in
general.
martinpitt added a commit that referenced this issue Feb 9, 2018
@martinpitt
Provide an option to run tests with -proposed enabled
0cc8285 
This reproduces #69. Don't enable it for CI as this is too unreliable in
general.
martinpitt added a commit that referenced this issue Feb 9, 2018
@martinpitt
Provide an option to run tests with -proposed enabled
9bd0ba9 
This reproduces #69. Don't enable it for CI as this is too unreliable in
general.
martinpitt pushed a commit to gicmo/umockdev that referenced this issue Feb 9, 2018
@gicmo @martinpitt
Wrap openat{,64}() to accommodate for libudev changes
b467b5b 
A recent change in libudev/systemd in device_set_syspath() changed
the pattern of syscalls (by using chase_symlink)
from:
    readlinkat (/sys/devices/XXX)
    canonicalize_file_name(/sys/devices/XXX)
to:
    open64 (/)
    openat64 (sys)
    openat64 (devices)
    openat64 (XXX)

This means it will not trigger trap_path and thus escape our faux
sysfs tree.

Modified by Martin Pitt:
 - More precise test for "sys" or "sys/..."
 - Add unit test for openat() behaviour
 - Turn into a macro and wrap openat() as well

Fixes martinpitt#69
@martinpitt martinpitt mentioned this issue Apr 26, 2018
Closed
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