A minimal library used to trace other library functions and system calls. Its primary target is EROS product generation.
Running make with no arguments will result in the following steps being
performed by the GNU compiler toolchain:
- Compile all
.csource files in the project root into position-independent assembly code (PIC). - Immediately assemble the in-memory PIC into object code, writing the output
to disk as
.ofiles. - Link the object files into a single dynamic library (shared object) and
write the output to disk as
libtrace.so.
If you wish to compile only a subset of source files into the library, you can
assign a space-delimited list of .c files to a variable named SRC and then
pass that variable to make.
To give the library a name other than trace, assign the alternate name to
LIBNAME and pass it onto make. You will need to pass this LIBNAME to
all subsequent make invocations, as well, including those used for
installation, testing, and clean up. Failure to do so will result in errors.
After building the library, a good idea would be to run tests on said library.
With a default build, make test will do just that.
If you passed a modified SRC to the build step, you will need to pass that
same SRC to make test so that only the appropriate tests are run. For
information on how tests are organized, see the "Adding tests"
section of DEVEL.md.
A simple make install will install your library to /usr/local/lib. To
install to a different location, pass one of the two variables to make:
PREFIX: overrides/usr/localLIBDIR: overrides the entire path
The user and group ownership of the library will be set to the EUID and EGID of
the make install process. Either assume the correct user and default group
before installation, or utilize sudo [-u USER] [-g GROUP] to get this right.
If you wish to test the installed version of the library, there is an
installcheck Makefile target for that. Like the test target, you must pass
SRC to make if you modified it during the build.
To use the library, simply run a command with the library's path included in
the LD_PRELOAD environment variable. For example:
LD_PRELOAD=/usr/local/lib/libtrace.so espa-submit
Because this library is used for tracing other library
550E
calls and system calls,
it is probably best to perform one-shot modification of LD_PRELOAD rather
than exporting it to all child processes.
There are two Makefile targets used for cleaning up files:
clean: removes build and test artifactsuninstall: removes the library from the installation location
If you overrode either PREFIX or LIBDIR during installation, you will need
to pass the overridden variable to make uninstall for that particular
operation to succeed.