[SixSigma]

As a demonstration I traced date(1) on CentOS. Here are the file accesses, if you are running diskless, each of these needs a round trip to the file server. (except the final 3, of course)

access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)

open("/etc/ld.so.cache", O_RDONLY) = 3

fstat(3, {st_mode=S_IFREG|0644, st_size=54185, ...}) = 0

close(3) = 0

open("/lib64/librt.so.1", O_RDONLY) = 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=43880, ...}) = 0

close(3) = 0

open("/lib64/libc.so.6", O_RDONLY) = 3

read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0p\356\1\0\0\0\0\0"..., 832) = 832

fstat(3, {st_mode=S_IFREG|0755, st_size=1921176, ...}) = 0

close(3) = 0

open("/lib64/libpthread.so.0", O_RDONLY) = 3

read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340]\0\0\0\0\0\0"..., 832) = 832

fstat(3, {st_mode=S_IFREG|0755, st_size=142640, ...}) = 0

close(3) = 0

open("/usr/lib/locale/locale-archive", O_RDONLY) = 3

fstat(3, {st_mode=S_IFREG|0644, st_size=99158576, ...}) = 0

close(3) = 0

open("/etc/localtime", O_RDONLY) = 3

fstat(3, {st_mode=S_IFREG|0644, st_size=3661, ...}) = 0

fstat(3, {st_mode=S_IFREG|0644, st_size=3661, ...}) = 0

read(3, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\7\0\0\0\7\0\0\0\0"..., 4096) = 3661

lseek(3, -2338, SEEK_CUR) = 1323

read(3, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\10\0\0\0\10\0\0\0\0"..., 4096) = 2338

close(3) = 0

fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0

write(1, "Tue Feb 24 08:57:58 GMT 2015\n", 29) = 29

close(1) = 0

[justincormack]

Ok, here is strace of date(1), which is dynamically linked, on Alpine Linux which uses Musl libc not glibc.

execve("/bin/date", ["date"], [/* 16 vars */]) = 0

mprotect(0x7777dcd5a000, 4096, PROT_READ) = 0

mprotect(0xdc2d89a3000, 4096, PROT_READ) = 0

arch_prctl(ARCH_SET_FS, 0xdc2d89a4268) = 0

set_tid_address(0xdc2d89a4298) = 2439

clock_gettime(CLOCK_REALTIME, {1424769563, 611556639}) = 0

open("/etc/localtime", O_RDONLY|O_NONBLOCK|O_CLOEXEC) = 3

fstat(3, {st_mode=S_IFREG|0644, st_size=118, ...}) = 0

mmap(NULL, 118, PROT_READ, MAP_SHARED, 3, 0) = 0x7777dcd57000

close(3) = 0

ioctl(1, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, {B38400 opost isig icanon echo ...}) = 0

writev(1, [{"Tue Feb 24 09:19:23 UTC 2015", 28}, {"\n", 1}], 2Tue Feb 24 09:19:23 UTC 2015 ) = 29

close(1) = 0

close(2) = 0

exit_group(0) = ?

+++ exited with 0 +++

[SixSigma]

That is worlds apart.

[SixSigma]

OpenBSD's ktrace is similar

31144 date CALL readlink(0x3c001c16,0xcfbe7048,0x3f)

31144 date NAMI "/etc/malloc.conf"

31144 date RET readlink -1 errno 2 No such file or directory

31144 date CALL open(0x3c001967,0<O_RDONLY>)

31144 date NAMI "/etc/localtime"

31144 date RET open 3

31144 date CALL open(0xcfbde9d4,0<O_RDONLY>)

31144 date NAMI "/usr/share/zoneinfo/posixrules

31144 date RET open 3

[justincormack]

Yes, in many ways Musl is a BSD style libc for Linux (even down to the license). Add pkgsrc and it is pretty BSD-like.