+++ /dev/null
-.\" %%%LICENSE_START(PUBLIC_DOMAIN)
-.\" This is in the public domain
-.\" %%%LICENSE_END
-.\"
-.TH LD.SO 8 2014-12-31 "GNU" "Linux Programmer's Manual"
-.SH NAME
-ld.so, ld-linux.so* \- dynamic linker/loader
-.SH SYNOPSIS
-The dynamic linker can be run either indirectly by running some
-dynamically linked program or library (in which case no command-line options
-to the dynamic linker can be passed and, in the ELF case, the dynamic linker
-which is stored in the
-.B .interp
-section of the program is executed) or directly by running:
-.P
-.I /lib/ld-linux.so.*
-[OPTIONS] [PROGRAM [ARGUMENTS]]
-.SH DESCRIPTION
-The programs
-.B ld.so
-and
-.B ld-linux.so*
-find and load the shared libraries needed by a program, prepare
-the program to run, and then run it.
-.LP
-Linux binaries require dynamic linking (linking at run time)
-unless the
-.B \-static
-option was given to
-.BR ld (1)
-during compilation.
-.LP
-The program
-.B ld.so
-handles a.out binaries, a format used long ago;
-.B ld-linux.so*
-handles ELF (\fI/lib/ld-linux.so.1\fP for libc5, \fI/lib/ld-linux.so.2\fP
-for glibc2), which everybody has been using for years now.
-Otherwise, both have the same behavior, and use the same
-support files and programs
-.BR ldd (1),
-.BR ldconfig (8),
-and
-.IR /etc/ld.so.conf .
-.LP
-When resolving library dependencies,
-the dynamic linker first inspects each dependency
-string to see if it contains a slash (this can occur if
-a library pathname containing slashes was specified at link time).
-If a slash is found, then the dependency string is interpreted as
-a (relative or absolute) pathname,
-and the library is loaded using that pathname.
-.LP
-If a library dependency does not contain a slash,
-then it is searched for in the following order:
-.IP o 3
-(ELF only) Using the directories specified in the
-DT_RPATH dynamic section attribute
-of the binary if present and DT_RUNPATH attribute does not exist.
-Use of DT_RPATH is deprecated.
-.IP o
-Using the environment variable
-.BR LD_LIBRARY_PATH .
-Except if the executable is a set-user-ID/set-group-ID binary,
-in which case it is ignored.
-.IP o
-(ELF only) Using the directories specified in the
-DT_RUNPATH dynamic section attribute
-of the binary if present.
-.IP o
-From the cache file
-.IR /etc/ld.so.cache ,
-which contains a compiled list of candidate libraries previously found
-in the augmented library path.
-If, however, the binary was linked with the
-.B \-z nodeflib
-linker option, libraries in the default library paths are skipped.
-Libraries installed in hardware capability directories (see below)
-are preferred to other libraries.
-.IP o
-In the default path
-.IR /lib ,
-and then
-.IR /usr/lib .
-If the binary was linked with the
-.B \-z nodeflib
-linker option, this step is skipped.
-.SS Rpath token expansion
-.PP
-.B ld.so
-understands certain strings in an rpath specification (DT_RPATH or DT_RUNPATH); those strings are substituted as follows
-.TP
-.IR $ORIGIN " (or equivalently " ${ORIGIN} )
-This expands to
-the directory containing the program or shared library.
-Thus, an application located in
-.I somedir/app
-could be compiled with
-
- gcc \-Wl,\-rpath,\(aq$ORIGIN/../lib\(aq
-
-so that it finds an associated shared library in
-.I somedir/lib
-no matter where
-.I somedir
-is located in the directory hierarchy.
-This facilitates the creation of "turn-key" applications that
-do not need to be installed into special directories,
-but can instead be unpacked into any directory
-and still find their own shared libraries.
-.TP
-.IR $LIB " (or equivalently " ${LIB} )
-This expands to
-.I lib
-or
-.I lib64
-depending on the architecture
-(e.g., on x86-64, it expands to
-.IR lib64
-and
-on x86-32, it expands to
-.IR lib ).
-.TP
-.IR $PLATFORM " (or equivalently " ${PLATFORM} )
-This expands to a string corresponding to the processor type
-of the host system (e.g., "x86_64").
-On some architectures, the Linux kernel doesn't provide a platform
-string to the dynamic linker.
-The value of this string is taken from the
-.BR AT_PLATFORM
-value in the auxiliary vector (see
-.BR getauxval (3)).
-.\" To get an idea of the places that $PLATFORM would match,
-.\" look at the output of the following:
-.\"
-.\" mkdir /tmp/d
-.\" LD_LIBRARY_PATH=/tmp/d strace -e open /bin/date 2>&1 | grep /tmp/d
-.\"
-.\" ld.so lets names be abbreviated, so $O will work for $ORIGIN;
-.\" Don't do this!!
-.SH OPTIONS
-.TP
-.B \-\-list
-List all dependencies and how they are resolved.
-.TP
-.B \-\-verify
-Verify that program is dynamically linked and this dynamic linker can handle
-it.
-.TP
-.B \-\-inhibit-cache
-Do not use /etc/ld.so.cache.
-.TP
-.B \-\-library\-path PATH
-Use PATH instead of
-.B LD_LIBRARY_PATH
-environment variable setting (see below).
-.TP
-.B \-\-inhibit\-rpath LIST
-Ignore RPATH and RUNPATH information in object names in LIST.
-This option is ignored if
-.B ld.so
-is set-user-ID or set-group-ID.
-.TP
-.B \-\-audit LIST
-Use objects named in LIST as auditors.
-.SH HARDWARE CAPABILITIES
-Some libraries are compiled using hardware-specific instructions which do
-not exist on every CPU.
-Such libraries should be installed in directories whose names define the
-required hardware capabilities, such as
-.IR /usr/lib/sse2/ .
-The dynamic linker checks these directories against the hardware of the
-machine and selects the most suitable version of a given library.
-Hardware capability directories can be cascaded to combine CPU features.
-The list of supported hardware capability names depends on the CPU.
-The following names are currently recognized:
-.TP
-.B Alpha
-ev4, ev5, ev56, ev6, ev67
-.TP
-.B MIPS
-loongson2e, loongson2f, octeon, octeon2
-.TP
-.B PowerPC
-4xxmac, altivec, arch_2_05, arch_2_06, booke, cellbe, dfp, efpdouble, efpsingle,
-fpu, ic_snoop, mmu, notb, pa6t, power4, power5, power5+, power6x, ppc32, ppc601,
-ppc64, smt, spe, ucache, vsx
-.TP
-.B SPARC
-flush, muldiv, stbar, swap, ultra3, v9, v9v, v9v2
-.TP
-.B s390
-dfp, eimm, esan3, etf3enh, g5, highgprs, hpage, ldisp, msa, stfle,
-z900, z990, z9-109, z10, zarch
-.TP
-.B x86 (32-bit only)
-acpi, apic, clflush, cmov, cx8, dts, fxsr, ht, i386, i486, i586, i686, mca, mmx,
-mtrr, pat, pbe, pge, pn, pse36, sep, ss, sse, sse2, tm
-.SH ENVIRONMENT
-Among the more important environment variables are the following:
-.TP
-.B LD_ASSUME_KERNEL
-(glibc since 2.2.3)
-Each shared library can inform the dynamic linker of the minimum kernel ABI
-version that it requires.
-(This requirement is encoded in an ELF note section that is viewable via
-.IR "readelf\ \-n"
-as a section labeled
-.BR NT_GNU_ABI_TAG .)
-At run time,
-the dynamic linker determines the ABI version of the running kernel and
-will reject loading shared libraries that specify minimum ABI versions
-that exceed that ABI version.
-
-.BR LD_ASSUME_KERNEL
-can be used to
-cause the dynamic linker to assume that it is running on a system with
-a different kernel ABI version.
-For example, the following command line causes the
-dynamic linker to assume it is running on Linux 2.2.5 when loading
-the shared libraries required by
-.IR myprog :
-
-.in +4n
-.nf
-$ \fBLD_ASSUME_KERNEL=2.2.5 ./myprog\fP
-.fi
-.in
-
-On systems that provide multiple versions of a shared library
-(in different directories in the search path) that have
-different minimum kernel ABI version requirements,
-.BR LD_ASSUME_KERNEL
-can be used to select the version of the library that is used
-(dependent on the directory search order).
-Historically, the most common use of the
-.BR LD_ASSUME_KERNEL
-feature was to manually select the older
-LinuxThreads POSIX threads implementation on systems that provided both
-LinuxThreads and NPTL
-(which latter was typically the default on such systems);
-see
-.BR pthreads (7).
-.TP
-.B LD_BIND_NOT
-(glibc since 2.2)
-Don't update the Global Offset Table (GOT) and Procedure Linkage Table (PLT)
-when resolving a symbol.
-.TP
-.B LD_BIND_NOW
-(libc5; glibc since 2.1.1)
-If set to a nonempty string,
-causes the dynamic linker to resolve all symbols
-at program startup instead of deferring function call resolution to the point
-when they are first referenced.
-This is useful when using a debugger.
-.TP
-.B LD_LIBRARY_PATH
-A colon-separated list of directories in which to search for
-ELF libraries at execution-time.
-Similar to the
-.B PATH
-environment variable.
-Ignored in set-user-ID and set-group-ID programs.
-.TP
-.B LD_PRELOAD
-A list of additional, user-specified, ELF shared
-libraries to be loaded before all others.
-The items of the list can be separated by spaces or colons.
-This can be used to selectively override functions in other shared libraries.
-The libraries are searched for using the rules given under DESCRIPTION.
-For set-user-ID/set-group-ID ELF binaries,
-preload pathnames containing slashes are ignored,
-and libraries in the standard search directories are loaded
-only if the set-user-ID permission bit is enabled on the library file.
-.TP
-.B LD_TRACE_LOADED_OBJECTS
-(ELF only)
-If set to a nonempty string, causes the program to list its dynamic library
-dependencies, as if run by
-.BR ldd (1),
-instead of running normally.
-.LP
-Then there are lots of more or less obscure variables,
-many obsolete or only for internal use.
-.TP
-.B LD_AOUT_LIBRARY_PATH
-(libc5)
-Version of
-.B LD_LIBRARY_PATH
-for a.out binaries only.
-Old versions of ld\-linux.so.1 also supported
-.BR LD_ELF_LIBRARY_PATH .
-.TP
-.B LD_AOUT_PRELOAD
-(libc5)
-Version of
-.B LD_PRELOAD
-for a.out binaries only.
-Old versions of ld\-linux.so.1 also supported
-.BR LD_ELF_PRELOAD .
-.TP
-.B LD_AUDIT
-(glibc since 2.4)
-A colon-separated list of user-specified, ELF shared objects
-to be loaded before all others in a separate linker namespace
-(i.e., one that does not intrude upon the normal symbol bindings that
-would occur in the process).
-These libraries can be used to audit the operation of the dynamic linker.
-.B LD_AUDIT
-is ignored for set-user-ID/set-group-ID binaries.
-
-The dynamic linker will notify the audit
-libraries at so-called auditing checkpoints\(emfor example,
-loading a new library, resolving a symbol,
-or calling a symbol from another shared object\(emby
-calling an appropriate function within the audit library.
-For details, see
-.BR rtld-audit (7).
-The auditing interface is largely compatible with that provided on Solaris,
-as described in its
-.IR "Linker and Libraries Guide" ,
-in the chapter
-.IR "Runtime Linker Auditing Interface" .
-.TP
-.B LD_BIND_NOT
-(glibc since 2.1.95)
-Do not update the GOT (global offset table) and PLT (procedure linkage table)
-after resolving a symbol.
-.TP
-.B LD_DEBUG
-(glibc since 2.1)
-Output verbose debugging information about the dynamic linker.
-If set to
-.B all
-prints all debugging information it has, if set to
-.B help
-prints a help message about which categories can be specified in this
-environment variable.
-Since glibc 2.3.4,
-.B LD_DEBUG
-is ignored for set-user-ID/set-group-ID binaries.
-.TP
-.B LD_DEBUG_OUTPUT
-(glibc since 2.1)
-File in which
-.B LD_DEBUG
-output should be written.
-The default is standard error.
-.B LD_DEBUG_OUTPUT
-is ignored for set-user-ID/set-group-ID binaries.
-.TP
-.B LD_DYNAMIC_WEAK
-(glibc since 2.1.91)
-Allow weak symbols to be overridden (reverting to old glibc behavior).
-For security reasons, since glibc 2.3.4,
-.B LD_DYNAMIC_WEAK
-is ignored for set-user-ID/set-group-ID binaries.
-.TP
-.B LD_HWCAP_MASK
-(glibc since 2.1)
-Mask for hardware capabilities.
-.TP
-.B LD_KEEPDIR
-(a.out only)(libc5)
-Don't ignore the directory in the names of a.out libraries to be loaded.
-Use of this option is strongly discouraged.
-.TP
-.B LD_NOWARN
-(a.out only)(libc5)
-Suppress warnings about a.out libraries with incompatible minor
-version numbers.
-.TP
-.B LD_ORIGIN_PATH
-(glibc since 2.1)
-Path where the binary is found (for non-set-user-ID programs).
-For security reasons, since glibc 2.4,
-.B LD_ORIGIN_PATH
-is ignored for set-user-ID/set-group-ID binaries.
-.\" Only used if $ORIGIN can't be determined by normal means
-.\" (from the origin path saved at load time, or from /proc/self/exe)?
-.TP
-.B LD_POINTER_GUARD
-(glibc since 2.4)
-Set to 0 to disable pointer guarding.
-Any other value enables pointer guarding, which is also the default.
-Pointer guarding is a security mechanism whereby some pointers to code
-stored in writable program memory (return addresses saved by
-.BR setjmp (3)
-or function pointers used by various glibc internals) are mangled
-semi-randomly to make it more difficult for an attacker to hijack
-the pointers for use in the event of a buffer overrun or
-stack-smashing attack.
-.TP
-.B LD_PROFILE
-(glibc since 2.1)
-The name of a (single) shared object to be profiled,
-specified either as a pathname or a soname.
-Profiling output is appended to the file whose name is:
-"\fI$LD_PROFILE_OUTPUT\fP/\fI$LD_PROFILE\fP.profile".
-.TP
-.B LD_PROFILE_OUTPUT
-(glibc since 2.1)
-Directory where
-.B LD_PROFILE
-output should be written.
-If this variable is not defined, or is defined as an empty string,
-then the default is
-.IR /var/tmp .
-.B LD_PROFILE_OUTPUT
-is ignored for set-user-ID and set-group-ID programs,
-which always use
-.IR /var/profile .
-.TP
-.B LD_SHOW_AUXV
-(glibc since 2.1)
-Show auxiliary array passed up from the kernel.
-For security reasons, since glibc 2.3.5,
-.B LD_SHOW_AUXV
-is ignored for set-user-ID/set-group-ID binaries.
-.\" FIXME
-.\" Document LD_TRACE_PRELINKING (e.g.: LD_TRACE_PRELINKING=libx1.so ./prog)
-.\" Available since glibc 2.3
-.\" Also enables DL_DEBUG_PRELINK
-.TP
-.B LD_USE_LOAD_BIAS
-.\" http://sources.redhat.com/ml/libc-hacker/2003-11/msg00127.html
-.\" Subject: [PATCH] Support LD_USE_LOAD_BIAS
-.\" Jakub Jelinek
-By default (i.e., if this variable is not defined)
-executables and prelinked
-shared objects will honor base addresses of their dependent libraries
-and (nonprelinked) position-independent executables (PIEs)
-and other shared objects will not honor them.
-If
-.B LD_USE_LOAD_BIAS
-is defined with the value 1, both executables and PIEs
-will honor the base addresses.
-If
-.B LD_USE_LOAD_BIAS
-is defined with the value 0,
-neither executables nor PIEs will honor the base addresses.
-This variable is ignored by set-user-ID and set-group-ID programs.
-.TP
-.B LD_VERBOSE
-(glibc since 2.1)
-If set to a nonempty string,
-output symbol versioning information about the
-program if the
-.B LD_TRACE_LOADED_OBJECTS
-environment variable has been set.
-.TP
-.B LD_WARN
-(ELF only)(glibc since 2.1.3)
-If set to a nonempty string, warn about unresolved symbols.
-.TP
-.B LDD_ARGV0
-(libc5)
-.IR argv [0]
-to be used by
-.BR ldd (1)
-when none is present.
-.SH FILES
-.PD 0
-.TP
-.I /lib/ld.so
-a.out dynamic linker/loader
-.TP
-.IR /lib/ld\-linux.so. { 1 , 2 }
-ELF dynamic linker/loader
-.TP
-.I /etc/ld.so.cache
-File containing a compiled list of directories in which to search for
-libraries and an ordered list of candidate libraries.
-.TP
-.I /etc/ld.so.preload
-File containing a whitespace-separated list of ELF shared libraries to
-be loaded before the program.
-.TP
-.B lib*.so*
-shared libraries
-.PD
-.SH NOTES
-The
-.B ld.so
-functionality is available for executables compiled using libc version
-4.4.3 or greater.
-ELF functionality is available since Linux 1.1.52 and libc5.
-.SH SEE ALSO
-.BR ld (1),
-.BR ldd (1),
-.BR pldd (1),
-.BR sprof (1),
-.BR dlopen (3),
-.BR getauxval (3),
-.BR rtld-audit (7),
-.BR ldconfig (8),
-.BR sln (8)
-.\" .SH AUTHORS
-.\" ld.so: David Engel, Eric Youngdale, Peter MacDonald, Hongjiu Lu, Linus
-.\" Torvalds, Lars Wirzenius and Mitch D'Souza
-.\" ld-linux.so: Roland McGrath, Ulrich Drepper and others.
-.\"
-.\" In the above, (libc5) stands for David Engel's ld.so/ld-linux.so.
-.SH COLOPHON
-This page is part of release 3.79 of the Linux
-.I man-pages
-project.
-A description of the project,
-information about reporting bugs,
-and the latest version of this page,
-can be found at
-\%http://www.kernel.org/doc/man\-pages/.
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