2004-11-03 13:51:07 +00:00
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.\" Copyright 1995-2000 David Engel (david@ods.com)
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.\" Copyright 1995 Rickard E. Faith (faith@cs.unc.edu)
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.\" Copyright 2000 Ben Collins (bcollins@debian.org)
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.\" Redone for GLibc 2.2
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.\" Copyright 2000 Jakub Jelinek (jakub@redhat.com)
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.\" Corrected.
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2016-07-05 10:49:52 +00:00
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.\" and Copyright (C) 2012, 2016, Michael Kerrisk <mtk.manpages@gmail.com>
|
ldd.1, capget.2, clone.2, create_module.2, fallocate.2, futex.2, get_kernel_syms.2, get_thread_area.2, getcpu.2, getitimer.2, getpid.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_list.2, mkdir.2, mknod.2, pciconfig_read.2, pivot_root.2, posix_fadvise.2, query_module.2, sendfile.2, set_thread_area.2, setns.2, unshare.2, __setfpucw.3, a64l.3, addseverity.3, argz_add.3, bindresvport.3, cabs.3, cacos.3, cacosh.3, canonicalize_file_name.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, ccos.3, ccosh.3, cerf.3, cexp.3, cexp2.3, cimag.3, clog.3, clog10.3, clog2.3, cmsg.3, conj.3, cpow.3, cproj.3, creal.3, csin.3, csinh.3, csqrt.3, ctan.3, ctanh.3, des_crypt.3, envz_add.3, fdim.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmtmsg.3, fpclassify.3, gamma.3, getpt.3, getrpcent.3, getrpcport.3, getttyent.3, isgreater.3, key_setsecret.3, lgamma.3, malloc_hook.3, mempcpy.3, nan.3, netlink.3, nextafter.3, putgrent.3, remove.3, remquo.3, rpc.3, rtime.3, rtnetlink.3, setaliasent.3, setnetgrent.3, signbit.3, significand.3, sincos.3, stdin.3, tgamma.3, xcrypt.3, xdr.3, cciss.4, hpsa.4, mouse.4, pts.4, sk98lin.4, tty_ioctl.4, wavelan.4, hosts.equiv.5, rpc.5, tzfile.5, boot.7, complex.7, ddp.7, fifo.7, futex.7, icmp.7, ip.7, ipv6.7, netdevice.7, netlink.7, packet.7, raw.7, rtnetlink.7, socket.7, tcp.7, udp.7, unix.7, x25.7, sync.8: Global fix: Put copyright info at top of page, followed by blank line and LICENSE
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-10 09:29:51 +00:00
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.\"
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ldd.1, clone.2, create_module.2, get_kernel_syms.2, get_thread_area.2, io_cancel.2, io_setup.2, io_submit.2, mkdir.2, mknod.2, query_module.2, set_thread_area.2, __setfpucw.3, hosts.equiv.5, sync.8: Added LICENSE_START(GPL_NOVERSION_ONELINE)
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-10 09:28:51 +00:00
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.\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
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2013-03-10 10:01:30 +00:00
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.\" Do not restrict distribution.
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2004-11-03 13:51:07 +00:00
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.\" May be distributed under the GNU General Public License
|
ldd.1, clone.2, create_module.2, get_kernel_syms.2, get_thread_area.2, io_cancel.2, io_setup.2, io_submit.2, mkdir.2, mknod.2, query_module.2, set_thread_area.2, __setfpucw.3, hosts.equiv.5, sync.8: Added LICENSE_START(GPL_NOVERSION_ONELINE)
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-10 09:28:51 +00:00
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.\" %%%LICENSE_END
|
ldd.1, arch_prctl.2, faccessat.2, fchmodat.2, fchownat.2, flock.2, futimesat.2, getcpu.2, getdents.2, getitimer.2, getpid.2, getresuid.2, getunwind.2, kexec_load.2, mkdirat.2, mknodat.2, openat.2, outb.2, perfmonctl.2, readlinkat.2, renameat.2, symlinkat.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, unlinkat.2: srcfix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-12 11:35:04 +00:00
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.\"
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iconv.1, ldd.1, accept.2, access.2, add_key.2, arch_prctl.2, bpf.2, chmod.2, chown.2, close_range.2, copy_file_range.2, execve.2, execveat.2, fanotify_mark.2, futex.2, futimesat.2, getpriority.2, intro.2, ioctl_tty.2, keyctl.2, link.2, membarrier.2, mkdir.2, mknod.2, mlock.2, mount.2, mount_setattr.2, open.2, open_by_handle_at.2, perf_event_open.2, pidfd_open.2, readlink.2, readv.2, rename.2, request_key.2, seccomp.2, sigaction.2, stat.2, statx.2, symlink.2, syscalls.2, umount.2, unlink.2, utimensat.2, wait.2, bsearch.3, fflush.3, getaddrinfo.3, getauxval.3, getopt.3, getsubopt.3, mkfifo.3, pthread_mutex_consistent.3, pthread_setname_np.3, pthread_tryjoin_np.3, scandir.3, sem_wait.3, stailq.3, strlen.3, strstr.3, termios.3, tsearch.3, wcslen.3, wcstok.3, wordexp.3, proc.5, capabilities.7, cgroups.7, fanotify.7, mount_namespaces.7, namespaces.7, path_resolution.7, pipe.7, posixoptions.7, user_namespaces.7, vdso.7, iconvconfig.8, ld.so.8: tstamp
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2021-08-27 00:44:07 +00:00
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.TH LDD 1 2021-08-27 "" "Linux Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.SH NAME
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2015-07-10 18:37:59 +00:00
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ldd \- print shared object dependencies
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2004-11-03 13:51:07 +00:00
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.SH SYNOPSIS
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2021-01-03 11:49:03 +00:00
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.nf
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2014-08-30 13:47:34 +00:00
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.BR ldd " [\fIoption\fP]... \fIfile\fP..."
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2021-01-03 11:49:03 +00:00
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.fi
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2004-11-03 13:51:07 +00:00
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.SH DESCRIPTION
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.B ldd
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2015-08-08 16:23:54 +00:00
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prints the shared objects (shared libraries) required by each program or
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2015-07-10 18:37:59 +00:00
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shared object specified on the command line.
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2020-09-24 07:57:27 +00:00
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An example of its use and output
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is the following:
|
2017-08-15 13:59:25 +00:00
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.PP
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2020-09-24 07:57:27 +00:00
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.in +4n
|
2017-08-15 13:59:25 +00:00
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.EX
|
ldd.1: Fix example command
Emanuele Torre via linux-man@:
[
I was reading the man page for ldd(1)[1]; and I read this in the first
paragraph of the DECRIPTION section:
ldd prints the shared objects (shared libraries) required by each
program or shared object specified on the command line. An
example of its use and output (using sed(1) to trim leading white
space for readability in this page) is the following:
$ ldd /bin/ls | sed 's/^ */ /'
linux-vdso.so.1 (0x00007ffcc3563000)
libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f87e5459000)
libcap.so.2 => /lib64/libcap.so.2 (0x00007f87e5254000)
libc.so.6 => /lib64/libc.so.6 (0x00007f87e4e92000)
libpcre.so.1 => /lib64/libpcre.so.1 (0x00007f87e4c22000)
libdl.so.2 => /lib64/libdl.so.2 (0x00007f87e4a1e000)
/lib64/ld-linux-x86-64.so.2 (0x00005574bf12e000)
libattr.so.1 => /lib64/libattr.so.1 (0x00007f87e4817000)
libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f87e45fa000)
This is a little confusing though since that sed(1) command does not
seem to work. (and also potentially misleading for someone who is trying
figure out how to parse ldd(1)'s output.)
ldd(1) prepends a TAB character (0x09) to each line, not spaces:
$ ldd /bin/ls | xxd | head -1
00000000: 096c 696e 7578 2d76 6473 6f2e 736f 2e31 .linux-vdso.so.1
I read ldd(1)'s source code[2] (it is part of glibc) and it seems to be
a bash script that tries to use different rtld programs ( ld.so(8) )
from an RTLDLIST.
Those, on my system, are:
* /usr/lib/ld-linux.so.2
* /usr/lib64/ld-linux-x86-64.so.2
* /usr/libx32/ld-linux-x32.so.2
And they all seem to also be part of glibc.
I have tried to follow the git history of glibc to see when the switch
from spaces to the TAB character occured, but, to me, it seems like
glibc.git/elf/rtld.c has always used '\t'; at since
6a76c115150318eae5d02eca76f2fc03be7bd029[3] (358th commit since glibc
started using the git repository repository - Nov 18th 1995): before
that commit there are not any results for `git grep '\\t'` in the elf
directory and I did not investigate further.
Still, at the time of that commit, glibc did not seem to have an ldd(1)
utility.
Perhaps the man page is old and its original author was using and
documenting an ldd(1) utility that was not part of glibc when he was
writing it.
Anyhow, since I think that sed(1) command will not work on any system
that uses, at least, the most recent version of glibc (because lld(1)
and the ld.so(8) programs it depends on are all part of glibc), I think
that that example should be changed to avoid confusions.
The output format of ldd(1) does not seem to be clearly defined, so I
think this would be a good option:
$ ldd /bin/ls | sed 's/^[[:space:]]*/ /'
NB: ^\s* should also work on most GNU/Linux systems, but \s is
non-standard or documented so I don not suggest using it in the man
page.
Another option could be to remove "the pipe to sed(1)" part and the note
in parentheses that explains why it was used by the original author.
Cheers.
emanuele6
[1]: https://man7.org/linux/man-pages/man1/ldd.1.html
[2]: https://sourceware.org/git/?p=glibc.git;a=blob;f=elf/ldd.bash.in;h=ba736464ac5e4a9390b1b6a39595035238250232;hb=5188a9d0265cc6f7235a8af1d31ab02e4a24853d
[3]: https://sourceware.org/git/?p=glibc.git;a=commit;h=6a76c115150318eae5d02eca76f2fc03be7bd029
///////
$ uname -a
Linux t420 5.10.54-1-lts #1 SMP Wed, 28 Jul 2021 15:05:20 +0000
x86_64 GNU/Linux
$ pacman -Qo ldd
/usr/bin/ldd is owned by glibc 2.33-5
$ pacman -Qo /usr/share/man/man1/ldd.1.gz
/usr/share/man/man1/ldd.1.gz is owned by man-pages 5.12-2
$ pacman -Qo /usr/lib/ld-linux.so.2
/usr/lib/ld-linux.so.2 is owned by lib32-glibc 2.33-5
$ pacman -Qo /usr/lib64/ld-linux-x86-64.so.2
/usr/lib/ld-linux-x86-64.so.2 is owned by glibc 2.33-5
$ pacman -F /usr/libx32/ld-linux-x32.so.2 || echo not available on arch linux.
not available on arch linux.
]
Reported-by: EmanueleTorre <torreemanuele6@gmail.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2021-08-08 08:41:32 +00:00
|
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$ \fBldd /bin/ls\fP
|
2021-01-09 22:21:02 +00:00
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linux\-vdso.so.1 (0x00007ffcc3563000)
|
2020-09-24 07:57:27 +00:00
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libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f87e5459000)
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libcap.so.2 => /lib64/libcap.so.2 (0x00007f87e5254000)
|
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libc.so.6 => /lib64/libc.so.6 (0x00007f87e4e92000)
|
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libpcre.so.1 => /lib64/libpcre.so.1 (0x00007f87e4c22000)
|
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libdl.so.2 => /lib64/libdl.so.2 (0x00007f87e4a1e000)
|
2021-01-09 22:21:02 +00:00
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/lib64/ld\-linux\-x86\-64.so.2 (0x00005574bf12e000)
|
2020-09-24 07:57:27 +00:00
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libattr.so.1 => /lib64/libattr.so.1 (0x00007f87e4817000)
|
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libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f87e45fa000)
|
2017-08-15 13:59:25 +00:00
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.EE
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.in
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.PP
|
2012-07-16 16:29:44 +00:00
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In the usual case,
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.B ldd
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invokes the standard dynamic linker (see
|
2012-09-23 14:30:10 +00:00
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.BR ld.so (8))
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2012-07-16 16:29:44 +00:00
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with the
|
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.B LD_TRACE_LOADED_OBJECTS
|
2016-05-10 16:32:43 +00:00
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environment variable set to 1.
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This causes the dynamic linker to inspect the program's dynamic dependencies,
|
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and find (according to the rules described in
|
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.BR ld.so (8))
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and load the objects that satisfy those dependencies.
|
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For each dependency,
|
getent.1, iconv.1, ldd.1, locale.1, localedef.1, memusage.1, memusagestat.1, pldd.1, sprof.1, time.1: tfix, use a one-font macro for a single argument
1) Use a single capital font macro for a genuine single argument.
The output is unchanged.
2) Remove quotation marks (") around a single argument.
The output is unchanged.
3) Change ".IR ab()" to ".IR ab ()"
A font is changed in the output.
mtk: I verified that the output is unchanged (other than fonts)
by comparing the output of:
for a in *.1; do man $a >> out.txt; done
before and after the patch.
Signed-off-by: Bjarni Ingi Gislason <bjarniig@rhi.hi.is>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2018-12-24 00:20:29 +00:00
|
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|
.B ldd
|
2016-05-10 16:32:43 +00:00
|
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|
displays the location of the matching object
|
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and the (hexadecimal) address at which it is loaded.
|
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(The
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2021-01-21 09:53:59 +00:00
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.I linux\-vdso
|
2016-05-10 16:32:43 +00:00
|
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and
|
2021-01-21 09:53:59 +00:00
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.I ld\-linux
|
2016-05-10 16:32:43 +00:00
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shared dependencies are special; see
|
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.BR vdso (7)
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and
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.BR ld.so (8).)
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.\"
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.SS Security
|
2016-07-04 15:25:03 +00:00
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Be aware that in some circumstances
|
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|
(e.g., where the program specifies an ELF interpreter other than
|
2021-01-21 09:53:59 +00:00
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.IR ld\-linux.so ),
|
2016-07-04 15:25:03 +00:00
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.\" The circumstances are where the program has an interpreter
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.\" other than ld-linux.so. In this case, ldd tries to execute the
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.\" program directly with LD_TRACE_LOADED_OBJECTS=1, with the
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.\" result that the program interpreter gets control, and can do
|
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.\" what it likes, or pass control to the program itself.
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.\" Much more detail at
|
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.\" http://www.catonmat.net/blog/ldd-arbitrary-code-execution/
|
|
|
|
|
some versions of
|
getent.1, iconv.1, ldd.1, locale.1, localedef.1, memusage.1, memusagestat.1, pldd.1, sprof.1, time.1: tfix, use a one-font macro for a single argument
1) Use a single capital font macro for a genuine single argument.
The output is unchanged.
2) Remove quotation marks (") around a single argument.
The output is unchanged.
3) Change ".IR ab()" to ".IR ab ()"
A font is changed in the output.
mtk: I verified that the output is unchanged (other than fonts)
by comparing the output of:
for a in *.1; do man $a >> out.txt; done
before and after the patch.
Signed-off-by: Bjarni Ingi Gislason <bjarniig@rhi.hi.is>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2018-12-24 00:20:29 +00:00
|
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|
.B ldd
|
2012-07-16 16:29:44 +00:00
|
|
|
may attempt to obtain the dependency information
|
2017-08-24 22:36:27 +00:00
|
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|
by attempting to directly execute the program,
|
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|
|
which may lead to the execution of whatever code is defined
|
2016-07-04 15:25:03 +00:00
|
|
|
in the program's ELF interpreter,
|
2017-08-24 22:36:27 +00:00
|
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|
and perhaps to execution of the program itself.
|
2012-07-16 16:29:44 +00:00
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.\" Mainline glibc's ldd allows this possibility (the line
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.\" try_trace "$file"
|
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.\" in glibc 2.15, for example), but many distro versions of
|
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|
.\" ldd seem to remove that code path from the script.
|
2017-11-30 09:58:02 +00:00
|
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|
(In glibc versions before 2.27,
|
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|
.\" glibc commit eedca9772e99c72ab4c3c34e43cc764250aa3e3c
|
2017-08-24 22:36:27 +00:00
|
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the upstream
|
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|
.B ldd
|
|
|
|
|
implementation did this for example,
|
|
|
|
|
although most distributions provided a modified version that did not.)
|
|
|
|
|
.PP
|
2012-07-16 16:29:44 +00:00
|
|
|
Thus, you should
|
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|
|
|
.I never
|
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employ
|
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|
|
|
.B ldd
|
|
|
|
|
on an untrusted executable,
|
|
|
|
|
since this may result in the execution of arbitrary code.
|
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|
A safer alternative when dealing with untrusted executables is:
|
2017-08-15 13:59:25 +00:00
|
|
|
.PP
|
|
|
|
|
.in +4n
|
|
|
|
|
.EX
|
|
|
|
|
$ \fBobjdump \-p /path/to/program | grep NEEDED\fP
|
|
|
|
|
.EE
|
|
|
|
|
.in
|
|
|
|
|
.PP
|
2017-05-13 18:39:16 +00:00
|
|
|
Note, however, that this alternative shows only the direct dependencies
|
|
|
|
|
of the executable, while
|
|
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.B ldd
|
|
|
|
|
shows the entire dependency tree of the executable.
|
2004-11-03 13:51:07 +00:00
|
|
|
.SH OPTIONS
|
|
|
|
|
.TP
|
2005-10-04 12:49:58 +00:00
|
|
|
.B \-\-version
|
2004-11-03 13:51:07 +00:00
|
|
|
Print the version number of
|
|
|
|
|
.BR ldd .
|
|
|
|
|
.TP
|
2015-04-18 12:47:33 +00:00
|
|
|
.BR \-v ", " \-\-verbose
|
2007-06-08 11:56:22 +00:00
|
|
|
Print all information, including, for example,
|
|
|
|
|
symbol versioning information.
|
2004-11-03 13:51:07 +00:00
|
|
|
.TP
|
2015-04-18 12:47:33 +00:00
|
|
|
.BR \-u ", " \-\-unused
|
2006-07-12 10:41:40 +00:00
|
|
|
Print unused direct dependencies.
|
2006-09-18 11:46:25 +00:00
|
|
|
(Since glibc 2.3.4.)
|
2006-07-12 10:41:40 +00:00
|
|
|
.TP
|
2015-04-18 12:47:33 +00:00
|
|
|
.BR \-d ", " \-\-data\-relocs
|
2004-11-03 13:51:07 +00:00
|
|
|
Perform relocations and report any missing objects (ELF only).
|
|
|
|
|
.TP
|
2015-04-18 12:47:33 +00:00
|
|
|
.BR \-r ", " \-\-function\-relocs
|
2004-11-03 13:51:07 +00:00
|
|
|
Perform relocations for both data objects and functions, and
|
|
|
|
|
report any missing objects or functions (ELF only).
|
|
|
|
|
.TP
|
|
|
|
|
.B \-\-help
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Usage information.
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2014-06-29 08:01:17 +00:00
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.\" .SH NOTES
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.\" The standard version of
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.\" .B ldd
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.\" comes with glibc2.
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.\" Libc5 came with an older version, still present
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.\" on some systems.
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.\" The long options are not supported by the libc5 version.
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.\" On the other hand, the glibc2 version does not support
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.\" .B \-V
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.\" and only has the equivalent
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.\" .BR \-\-version .
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.\" .LP
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.\" The libc5 version of this program will use the name of a library given
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.\" on the command line as-is when it contains a \(aq/\(aq; otherwise it
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.\" searches for the library in the standard locations.
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.\" To run it
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.\" on a shared library in the current directory, prefix the name with "./".
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2004-11-03 13:51:07 +00:00
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.SH BUGS
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.B ldd
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does not work on a.out shared libraries.
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.PP
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.B ldd
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does not work with some extremely old a.out programs which were
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built before
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.B ldd
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support was added to the compiler releases.
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If you use
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.B ldd
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on one of these programs, the program will attempt to run with
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2013-06-08 04:48:01 +00:00
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.I argc
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= 0 and the results will be unpredictable.
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2004-11-03 13:51:07 +00:00
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.\" .SH AUTHOR
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.\" David Engel.
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.\" Roland McGrath and Ulrich Drepper.
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.SH SEE ALSO
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2014-06-09 10:19:42 +00:00
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.BR pldd (1),
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2015-03-08 02:19:54 +00:00
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.BR sprof (1),
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2004-11-03 13:51:07 +00:00
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.BR ld.so (8),
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.BR ldconfig (8)
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