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Diffstat (limited to 'sbin/ldconfig/ldconfig.8')
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diff --git a/sbin/ldconfig/ldconfig.8 b/sbin/ldconfig/ldconfig.8 new file mode 100644 index 000000000000..e363269baab4 --- /dev/null +++ b/sbin/ldconfig/ldconfig.8 @@ -0,0 +1,98 @@ +.Dd October 3, 1993 +.Dt LDCONFIG 8 +.Os NetBSD 0.9 +.Sh NAME +.Nm ldconfig +.Nd configure the shared library cache +.Sh SYNOPSIS +.Nm ldconfig +.Op Fl rsv +.Op Ar directory Ar ... +.Sh DESCRIPTION +.Nm +is used to prepare a set of +.Dq hints +for use by the run-time linker +.Xr ld.so +to facilitate quick lookup of shared libraries available in multiple +directories. It scans a set of built-in system directories and any +.Ar directories +specified on the command line (in the given order) looking for shared +libraries and stores the results in the file +.Xr /var/run/ld.so.hints +to forstall the overhead that would otherwise result from the +directory search operations +.Xr ld.so +would have to perform to load the required shared libraries. +.Pp +The shared libraries so found will be automatically available for loading +if needed by the program being prepared for execution. This obviates the need +for storing search paths within the executable. +.Pp +The +.Ev LD_LIBRARY_PATH +environment variable can be used to override the use of +directories (or the order thereof) from the cache or to specify additional +directories where shared libraries might be found. +.Ev LD_LIBRARY_PATH +is a +.Sq \: +separated list of directory paths which are searched by +.Xr ld.so +when it needs to load a shared library. It can be viewed as the run-time +equivalent of the +.Fl L +switch of +.Xr ld. +.Pp +.Nm Ldconfig +is typically run as part of the boot sequence. +.Pp +The following options recognized by +.Nm ldconfig: +.Bl -tag -width indent +.It Fl r +Lists the current contents of +.Xr ld.so.hints +on the standard output. The hints file will not be modified. +.It Fl s +Do not scan +.Nm ldconfig +'s builtin system directories +.Sq /usr/lib +and +.Sq /usr/local/lib +for shared libraries. +.It Fl v +Switch on verbose mode. +.Sh Security +Special care must be taken when loading shared libraries into the address +space of +.Ev set-user-Id +programs. Whenever such a program is run, +.Xr ld.so +will only load shared libraries from the +.Ev ld.so.hints +file. In particular, the +.Ev LD_LIBRARY_PATH +is not used to search for libraries. Thus, the role of ldconfig is dual. In +addition to building a set of hints for quick lookup, it also serves to +specify the trusted collection of directories from which shared objects can +be safely loaded. It is presumed that the set of directories specified to +.Nm ldconfig +are under control of the system's administrator. +.Xr ld.so +further assists set-user-Id programs by erasing the +.Ev LD_LIBRARY_PATH +from the environment. + +.Sh FILES +.Xr /var/run/ld.so.hints +.Sh SEE ALSO +.Xr ld 1 , +.Xr link 5 +.Sh HISTORY +A +.Nm +utility first appeared in SunOS 4.0, it appeared in its current form +in NetBSD 0.9a. |