Pádraig Brady wrote:
> I also notice these extra systemd calls from ls,
> even though it doesn't link directly with systemd!
> It's coming from user db lookup which connects to systemd
> (over polled sockets) though nss config.
Yes, it comes from /etc/nsswitch.conf.
> Now systemd is providing support for DynamicUser=, homed, or nspawn containers
> but it's unfortunate that it's quite heavy weight for all users
> even with basic command like ls.
What do you expect from the default configuration of the testing release
of RedHat's flagship Enterprise distribution? /etc/nsswitch.conf can
be customized; that's the purpose of this file, so that system administrators
who want to minimize the number of system calls can do so.
Bruno
execve("/usr/sbin/ls", ["ls", "-ld", "/"], 0x7fff5a884df0 /* 30 vars */) = 0
brk(NULL) = 0x559289173000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=89307, ...}) = 0
mmap(NULL, 89307, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff4a3ac0000
close(3) = 0
openat(AT_FDCWD, "/lib64/libselinux.so.1", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=204752, ...}) = 0
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff4a3abe000
mmap(NULL, 206288, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff4a3a8b000
mmap(0x7ff4a3aac000, 57344, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x21000) = 0x7ff4a3aac000
mmap(0x7ff4a3aba000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2f000) = 0x7ff4a3aba000
mmap(0x7ff4a3abc000, 5584, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7ff4a3abc000
close(3) = 0
openat(AT_FDCWD, "/lib64/libcap.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0 ^\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=48976, ...}) = 0
mmap(NULL, 49224, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff4a3a7e000
mmap(0x7ff4a3a85000, 16384, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x7000) = 0x7ff4a3a85000
mmap(0x7ff4a3a89000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xa000) = 0x7ff4a3a89000
close(3) = 0
openat(AT_FDCWD, "/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\2408\0\0\0\0\0\0"..., 832) = 832
pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784, 64) = 784
fstat(3, {st_mode=S_IFREG|0755, st_size=2490288, ...}) = 0
pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784, 64) = 784
mmap(NULL, 2075504, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff4a3883000
mmap(0x7ff4a39f7000, 495616, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x174000) = 0x7ff4a39f7000
mmap(0x7ff4a3a70000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1ed000) = 0x7ff4a3a70000
mmap(0x7ff4a3a76000, 31600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7ff4a3a76000
close(3) = 0
openat(AT_FDCWD, "/lib64/libpcre2-8.so.0", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=724280, ...}) = 0
mmap(NULL, 721368, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff4a37d2000
mmap(0x7ff4a3853000, 188416, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x81000) = 0x7ff4a3853000
mmap(0x7ff4a3881000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xae000) = 0x7ff4a3881000
close(3) = 0
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff4a37d0000
arch_prctl(ARCH_SET_FS, 0x7ff4a37d0e00) = 0
set_tid_address(0x7ff4a37d1428) = 7431
set_robust_list(0x7ff4a37d10e0, 24) = 0
rseq({cpu_id_start=0, cpu_id=RSEQ_CPU_ID_UNINITIALIZED, rseq_cs=NULL, flags=0, node_id=0, mm_cid=0, slice_ctrl={request=0, granted=0, __reserved=0}, __reserved=0}, 32, 0, 0x53053053) = 0
mprotect(0x7ff4a3a70000, 16384, PROT_READ) = 0
mprotect(0x7ff4a3881000, 4096, PROT_READ) = 0
mprotect(0x7ff4a3a89000, 4096, PROT_READ) = 0
mprotect(0x7ff4a3aba000, 4096, PROT_READ) = 0
mprotect(0x559256efd000, 8192, PROT_READ) = 0
mprotect(0x7ff4a3b14000, 8192, PROT_READ) = 0
prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0
getrandom("\x2f\x03\x0c\x1a\xc6\x54\x47\x32", 8, GRND_NONBLOCK) = 8
munmap(0x7ff4a3ac0000, 89307) = 0
prctl(PR_CAPBSET_READ, CAP_MAC_OVERRIDE) = 1
prctl(PR_CAPBSET_READ, 0x30 /* CAP_??? */) = -1 EINVAL (Invalid argument)
prctl(PR_CAPBSET_READ, CAP_CHECKPOINT_RESTORE) = 1
prctl(PR_CAPBSET_READ, 0x2c /* CAP_??? */) = -1 EINVAL (Invalid argument)
prctl(PR_CAPBSET_READ, 0x2a /* CAP_??? */) = -1 EINVAL (Invalid argument)
prctl(PR_CAPBSET_READ, 0x29 /* CAP_??? */) = -1 EINVAL (Invalid argument)
statfs("/sys/fs/selinux", {f_type=SELINUX_MAGIC, f_bsize=4096, f_blocks=0, f_bfree=0, f_bavail=0, f_files=0, f_ffree=0, f_fsid={val=[0x15, 0]}, f_namelen=255, f_frsize=4096, f_flags=ST_VALID|ST_NOSUID|ST_NOEXEC|ST_RELATIME}) = 0
statfs("/sys/fs/selinux", {f_type=SELINUX_MAGIC, f_bsize=4096, f_blocks=0, f_bfree=0, f_bavail=0, f_files=0, f_ffree=0, f_fsid={val=[0x15, 0]}, f_namelen=255, f_frsize=4096, f_flags=ST_VALID|ST_NOSUID|ST_NOEXEC|ST_RELATIME}) = 0
brk(NULL) = 0x559289173000
brk(0x559289194000) = 0x559289194000
access("/etc/selinux/config", F_OK) = 0
openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=233380912, ...}) = 0
mmap(NULL, 233380912, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff495800000
close(3) = 0
ioctl(1, TCGETS2, {c_iflag=ICRNL|IXON|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ICANON|ECHO|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = 0
openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=2998, ...}) = 0
read(3, "# Locale name alias data base.\n#"..., 4096) = 2998
read(3, "", 4096) = 0
close(3) = 0
openat(AT_FDCWD, "/usr/share/locale/en_US.UTF-8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.UTF-8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
statx(AT_FDCWD, "/", AT_STATX_SYNC_AS_STAT|AT_SYMLINK_NOFOLLOW|AT_NO_AUTOMOUNT, STATX_MODE|STATX_NLINK|STATX_UID|STATX_GID|STATX_MTIME|STATX_SIZE, {stx_mask=STATX_ALL|STATX_MNT_ID|STATX_SUBVOL, stx_attributes=STATX_ATTR_MOUNT_ROOT, stx_mode=S_IFDIR|0555, stx_size=154, ...}) = 0
llistxattr("/", "security.selinux\0", 152) = 17
lgetxattr("/", "security.selinux", "system_u:object_r:root_t:s0", 255) = 28
access("/var/run/setrans/.setrans-unix", F_OK) = -1 ENOENT (No such file or directory)
futex(0x7ff4a3abd5a0, FUTEX_WAKE_PRIVATE, 2147483647) = 0
newfstatat(AT_FDCWD, "/etc/nsswitch.conf", {st_mode=S_IFREG|0644, st_size=687, ...}, 0) = 0
newfstatat(AT_FDCWD, "/", {st_mode=S_IFDIR|0555, st_size=154, ...}, 0) = 0
openat(AT_FDCWD, "/etc/nsswitch.conf", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=687, ...}) = 0
read(3, "# Generated by authselect\n# Do n"..., 4096) = 687
read(3, "", 4096) = 0
fstat(3, {st_mode=S_IFREG|0644, st_size=687, ...}) = 0
close(3) = 0
openat(AT_FDCWD, "/etc/passwd", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=3027, ...}) = 0
lseek(3, 0, SEEK_SET) = 0
read(3, "root:x:0:0:Super User:/root:/bin"..., 4096) = 3027
lseek(3, 38, SEEK_SET) = 38
close(3) = 0
newfstatat(AT_FDCWD, "/etc/nsswitch.conf", {st_mode=S_IFREG|0644, st_size=687, ...}, 0) = 0
openat(AT_FDCWD, "/etc/group", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=1056, ...}) = 0
lseek(3, 0, SEEK_SET) = 0
read(3, "root:x:0:\nsys:x:3:\nadm:x:4:\ntty:"..., 4096) = 1056
lseek(3, 10, SEEK_SET) = 10
close(3) = 0
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=89307, ...}) = 0
mmap(NULL, 89307, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff4a3ac0000
close(3) = 0
openat(AT_FDCWD, "/lib64/libnss_systemd.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=482848, ...}) = 0
mmap(NULL, 473760, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff4a375c000
mmap(0x7ff4a37ad000, 114688, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x51000) = 0x7ff4a37ad000
mmap(0x7ff4a37c9000, 28672, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6d000) = 0x7ff4a37c9000
close(3) = 0
openat(AT_FDCWD, "/lib64/libm.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1153848, ...}) = 0
mmap(NULL, 1138704, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff4956e9000
mmap(0x7ff495778000, 548864, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x8f000) = 0x7ff495778000
mmap(0x7ff4957fe000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x114000) = 0x7ff4957fe000
close(3) = 0
openat(AT_FDCWD, "/lib64/libgcc_s.so.1", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=186544, ...}) = 0
mmap(NULL, 180680, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff4a372f000
mmap(0x7ff4a3753000, 28672, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x24000) = 0x7ff4a3753000
mmap(0x7ff4a375a000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2b000) = 0x7ff4a375a000
mmap(0x7ff4a375b000, 456, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7ff4a375b000
close(3) = 0
mprotect(0x7ff4a375a000, 4096, PROT_READ) = 0
mprotect(0x7ff4957fe000, 4096, PROT_READ) = 0
mprotect(0x7ff4a37c9000, 24576, PROT_READ) = 0
munmap(0x7ff4a3ac0000, 89307) = 0
futex(0x7ff4a37cfa58, FUTEX_WAKE_PRIVATE, 2147483647) = 0
rt_sigprocmask(SIG_BLOCK, [HUP USR1 USR2 PIPE ALRM CHLD TSTP URG VTALRM PROF WINCH IO], [], 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
fstat(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(0x88, 0x1), ...}) = 0
openat(AT_FDCWD, "/etc/localtime", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=2298, ...}) = 0
fstat(3, {st_mode=S_IFREG|0644, st_size=2298, ...}) = 0
read(3, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\t\0\0\0\t\0\0\0\0"..., 4096) = 2298
lseek(3, -1449, SEEK_CUR) = 849
read(3, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\t\0\0\0\t\0\0\0\0"..., 4096) = 1449
lseek(3, 2297, SEEK_SET) = 2297
close(3) = 0
write(1, "dr-xr-xr-x. 1 root root 154 Apr "..., 43) = 43
close(1) = 0
close(2) = 0
exit_group(0) = ?
+++ exited with 0 +++
