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= MockLibc 1.1 =
Mocks of common libc functions who have global state. Version 1.1 focuses on
NSS related methods (user, group, and netgroup queries).
This library is a re-implementation of specific libc methods, not a tool for
creating mock functions. Use MockLibc to create a consistent environment for
your unit tests, when they need to query system information.
== Requirements ==
* Tests require the 'id' and 'innetgr' commands in the PATH
== Build ==
$ cd mocklibc-1.1
$ ./configure
$ make
$ make check
== Install ==
$ make install
== Example Usage ==
$ id foo
id: foo: No such user
$ export MOCK_PASSWD=./testdata/passwd
$ export MOCK_GROUP=./testdata/group
$ mkdir ./testdata
$ echo “foo:x:9000:9000::/home/foo:/bin/bash” > “$MOCK_PASSWD”
$ echo “mockusers:x:9001:foo” > “$MOCK_GROUP”
$ mocklibc id foo
uid=9000(foo) gid=9000(foo) groups=9000(foo),9001(mockusers)
== Use without install ==
mocklibc can be used directly from the bin directory, without being installed:
$ cd mocklibc-1.1
$ ./configure
$ make
$ bin/mocklibc id foo
== Hacking ==
If using a git checkout instead of a source tarball, always run
'autogen --install' before './configure'. Whenever a Makefile.am or
configure.ac is modified, run 'autogen' again without --install.
== Mocked Functions ==
NSS Methods completely disregard /etc/nsswitch.conf, similar to using just
"files", but with modified paths. DNS is not modified and no *_r methods will
be implemented in this version.
* pwd.h (NSS users, configured with MOCK_PASSWD)
* setpwent
* getpwent
* endpwent
* getpwnam
* getpwuid
* grp.h (NSS groups, configured with MOCK_GROUP)
* setpwent
* getpwent
* endpwent
* getpwnam
* getpwuid
* netdb.h (NSS netgroups, no DNS, configured with MOCK_NETGROUP)
* setnetgrent
* getnetgrent
* endnetgrent
* innetgr
== Configuration ==
All configuration is handled through environment variables, though specific
mocklibc_* methods may be added in the future for things like time and random
number generation.
Environment Variables:
* MOCK_PASSWD - Path to /etc/passwd replacement
* MOCK_GROUP - Path to /etc/group replacement
* MOCK_NETGROUP - Path to /etc/netgroup replacement
== F.A.Q. ==
* Why not use a chroot? Chroot requires root, and forcing unit tests to run as
root is not desirable.
* Is there something that already does this? There are mock frameworks for C,
but this library is an implementation of specific common mocks C developers
need. A mock of set/get/endgrent still requires some basic code for iterating
group objects. This library provides that.
== TODO ==
* Add functions to free unused memory in 'netdb_netgroup.c'. It leaks a ton of
memory every call. See TODO comments in code.
== Future ==
The following may be supported in the future, and I'm taking requests for other
functionality at 'vonhollen@gmail.com'.
Features:
* Redirect syslog messages to file at $MOCK_SYSLOG
* '*_r' methods in pwd.h, grp.h, and netdb.h
* netdb.h: gethostbyname, gethostbyaddr, getaddrinfo, get/freeaddrinfo
* Whitelist apps with $MOCK_ONLY (includes list of argv[0] names)
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