From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue, 21 Feb 2012 16:25:14 +0000 (-0500)
Subject: Detect and document dependency on -ldl on Linux, -lc on BSD for dlopen
X-Git-Tag: v2.1.0-rc1~97^2~18
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=c6c454ab6ca9d19041d4f16e6139b514fe1b954f;p=lttng-ust.git

Detect and document dependency on -ldl on Linux, -lc on BSD for dlopen

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/README b/README
index e2b52aa0..78ed56f6 100644
--- a/README
+++ b/README
@@ -67,7 +67,7 @@ USAGE:
       "TRACEPOINT_DEFINE" and include the tracepoint provider.
     - Use "-I." for the compilation unit containing the tracepoint
       provider include (e.g. tp.c).
-    - Link application with "-ldl".
+    - Link application with "-ldl" on Linux, with "-lc" on BSD.
     - If building the provider directly into the application,
       link the application with "-llttng-ust".
     - If building a static library for the provider, link the static
@@ -75,7 +75,7 @@ USAGE:
     - Include the tracepoint provider header into all C files using
       the provider.
     - Example:
-        tests/hello/  hello.c tp.c ust_tests_hello.h Makefile.example
+        tests/hello/  hello.c tp.c ust_tests_hello.h Makefile.example.*
 
   2) Compile the Tracepoint Provider separately from the application,
      using dynamic linking:
@@ -87,7 +87,7 @@ USAGE:
       files that use the provider.
     - Compile the tracepoint provider with "-I.".
     - Link the tracepoint provider with "-llttng-ust".
-    - Link application with "-ldl".
+    - Link application with "-ldl" on Linux, "-lc" on BSD.
     - Set a LD_PRELOAD environment to preload the tracepoint provider
       shared object before starting the application when tracing is
       needed.
diff --git a/configure.ac b/configure.ac
index aa0fac34..167cd880 100644
--- a/configure.ac
+++ b/configure.ac
@@ -42,7 +42,23 @@ AC_PROG_MAKE_SET
 LT_INIT
 
 ## Checks for libraries.
-AC_CHECK_LIB([dl], [dlopen])
+AC_CHECK_LIB([dl], [dlopen],
+[
+	have_libdl=yes
+],
+[
+	#libdl not found, check for dlopen in libc.
+	AC_CHECK_LIB([c], [dlopen],
+	[
+		have_libc_dl=yes
+	],
+	[
+		AC_MSG_ERROR([Cannot find dlopen in libdl nor libc. Use [LDFLAGS]=-Ldir to specify their location.])
+	])
+])
+AM_CONDITIONAL([LTTNG_UST_BUILD_WITH_LIBDL], [test "x$have_libdl" = "xyes"])
+AM_CONDITIONAL([LTTNG_UST_BUILD_WITH_LIBC_DL], [test "x$have_libc_dl" = "xyes"])
+
 AC_CHECK_LIB([pthread], [pthread_create])
 
 # Check for libuuid
@@ -59,7 +75,7 @@ AC_CHECK_LIB([uuid], [uuid_generate],
 		have_libc_uuid=yes
 	],
 	[
-		AC_MSG_ERROR([Cannot find libuuid uuid_generate nor libc uuid_create. Use [LDFLAGS]=-Ldir to specify its location.])
+		AC_MSG_ERROR([Cannot find libuuid uuid_generate nor libc uuid_create. Use [LDFLAGS]=-Ldir to specify their location.])
 	])
 ]
 )
diff --git a/doc/examples/easy-ust/Makefile b/doc/examples/easy-ust/Makefile
index 597071b5..3d043df4 100644
--- a/doc/examples/easy-ust/Makefile
+++ b/doc/examples/easy-ust/Makefile
@@ -16,7 +16,8 @@
 # the "html" target helps for documentation (req. code2html)
 
 CC = gcc
-LIBS = -ldl -llttng-ust
+LIBS = -ldl -llttng-ust		# On Linux
+#LIBS = -lc -llttng-ust		# On BSD
 CFLAGS = -I.
 
 all: sample
diff --git a/doc/examples/gen-tp/Makefile b/doc/examples/gen-tp/Makefile
index b29eed4c..518f0174 100644
--- a/doc/examples/gen-tp/Makefile
+++ b/doc/examples/gen-tp/Makefile
@@ -16,7 +16,9 @@
 # provider probe.
 
 CC = gcc
-LIBS = -ldl -llttng-ust
+
+LIBS = -ldl -llttng-ust		#On Linux
+#LIBS = -lc -llttng-ust		#On BSD
 
 all: sample
 
diff --git a/liblttng-ust-fork/Makefile.am b/liblttng-ust-fork/Makefile.am
index e0e42a3f..49466f64 100644
--- a/liblttng-ust-fork/Makefile.am
+++ b/liblttng-ust-fork/Makefile.am
@@ -4,6 +4,13 @@ AM_CFLAGS = -fno-strict-aliasing
 lib_LTLIBRARIES = liblttng-ust-fork.la
 liblttng_ust_fork_la_SOURCES = ustfork.c
 liblttng_ust_fork_la_LIBADD = \
-	-ldl \
 	$(top_builddir)/liblttng-ust/liblttng-ust.la
+
+if LTTNG_UST_BUILD_WITH_LIBDL
+liblttng_ust_fork_la_LIBADD += -ldl
+endif
+if LTTNG_UST_BUILD_WITH_LIBC_DL
+liblttng_ust_fork_la_LIBADD += -lc
+endif
+
 libustfork_CFLAGS = -DUST_COMPONENT=liblttng-ust-fork -fno-strict-aliasing
diff --git a/liblttng-ust-libc-wrapper/Makefile.am b/liblttng-ust-libc-wrapper/Makefile.am
index 6220f76c..5b3f7f0d 100644
--- a/liblttng-ust-libc-wrapper/Makefile.am
+++ b/liblttng-ust-libc-wrapper/Makefile.am
@@ -5,9 +5,16 @@ lib_LTLIBRARIES = liblttng-ust-libc-wrapper.la
 liblttng_ust_libc_wrapper_la_SOURCES = \
 	lttng-ust-malloc.c \
 	ust_libc.h
-liblttng_ust_libc_wrapper_la_LIBADD = -ldl \
+liblttng_ust_libc_wrapper_la_LIBADD = \
 	-L$(top_builddir)/liblttng-ust/.libs \
 	-llttng-ust
 
+if LTTNG_UST_BUILD_WITH_LIBDL
+liblttng_ust_libc_wrapper_la_LIBADD += -ldl
+endif
+if LTTNG_UST_BUILD_WITH_LIBC_DL
+liblttng_ust_libc_wrapper_la_LIBADD += -lc
+endif
+
 noinst_SCRIPTS = run
 EXTRA_DIST = run
diff --git a/tests/demo/Makefile.am b/tests/demo/Makefile.am
index f96980ed..e4570ff0 100644
--- a/tests/demo/Makefile.am
+++ b/tests/demo/Makefile.am
@@ -33,5 +33,11 @@ liblttng_ust_provider_ust_tests_demo3_la_LDFLAGS = \
 
 noinst_PROGRAMS = demo
 demo_SOURCES = demo.c ust_tests_demo.h
-# The demo program only depends on libdl.
-demo_LDFLAGS = -ldl
+# The demo program only depends on libdl/libc for dlopen().
+if LTTNG_UST_BUILD_WITH_LIBDL
+demo_LDADD = -ldl
+endif
+if LTTNG_UST_BUILD_WITH_LIBC_DL
+demo_LDADD = -lc
+endif
+
diff --git a/tests/demo/README b/tests/demo/README
index cc51b67c..03ee4ee1 100644
--- a/tests/demo/README
+++ b/tests/demo/README
@@ -4,7 +4,8 @@ demo-trace shell script preloads the provider shared objects before
 executing the demo. Executing "demo" without the shell wrapper will not
 provide any tracing support. This ensures the demo binary can be
 distributed on distros without depending on having liblttng-ust.so in
-place. Note: the "demo" program must be compiled with "-ldl".
+place. Note: the "demo" program must be compiled with "-ldl" on Linux,
+with "-lc" on BSD.
 
 The simplest command to trace the demo program are:
 lttng create
diff --git a/tests/dlopen/Makefile.am b/tests/dlopen/Makefile.am
index 89fd9dbf..de05346c 100644
--- a/tests/dlopen/Makefile.am
+++ b/tests/dlopen/Makefile.am
@@ -6,7 +6,14 @@ libdummy_la_SOURCES = libdummy.c
 libdummy_la_LIBADD = $(top_builddir)/libust/libust.la $(top_builddir)/libust-initializer.o
 libdummy_la_LDFLAGS = -rpath /nowhere
 dlopen_SOURCES = dlopen.c
-dlopen_LDADD = -ldl $(top_builddir)/libust/libust.la $(top_builddir)/libust-initializer.o
+dlopen_LDADD = $(top_builddir)/libust/libust.la $(top_builddir)/libust-initializer.o
+
+if LTTNG_UST_BUILD_WITH_LIBDL
+dlopen_LDADD += -ldl
+endif
+if LTTNG_UST_BUILD_WITH_LIBC_DL
+dlopen_LDADD += -lc
+endif
 
 noinst_SCRIPTS = run
 EXTRA_DIST = run
diff --git a/tests/hello-static-lib/Makefile.am b/tests/hello-static-lib/Makefile.am
index 0eff080c..66334894 100644
--- a/tests/hello-static-lib/Makefile.am
+++ b/tests/hello-static-lib/Makefile.am
@@ -8,7 +8,14 @@ liblttng_ust_provider_ust_test_hello_la_LIBADD = \
 
 noinst_PROGRAMS = hello
 hello_SOURCES = hello.c
-hello_LDADD = -ldl liblttng-ust-provider-ust-test-hello.la
+hello_LDADD = liblttng-ust-provider-ust-test-hello.la
+
+if LTTNG_UST_BUILD_WITH_LIBDL
+hello_LDADD += -ldl
+endif
+if LTTNG_UST_BUILD_WITH_LIBC_DL
+hello_LDADD += -lc
+endif
 
 noinst_SCRIPTS = run
 EXTRA_DIST = run
diff --git a/tests/hello.cxx/Makefile.am b/tests/hello.cxx/Makefile.am
index 3e84796a..f56f431c 100644
--- a/tests/hello.cxx/Makefile.am
+++ b/tests/hello.cxx/Makefile.am
@@ -4,5 +4,12 @@ noinst_PROGRAMS = hello
 hello_SOURCES = hello.cpp tp.c ust_tests_hello.h
 hello_LDADD = $(top_builddir)/liblttng-ust/liblttng-ust.la
 
+if LTTNG_UST_BUILD_WITH_LIBDL
+hello_LDADD += -ldl
+endif
+if LTTNG_UST_BUILD_WITH_LIBC_DL
+hello_LDADD += -lc
+endif
+
 noinst_SCRIPTS = run
 EXTRA_DIST = run
diff --git a/tests/hello/Makefile.am b/tests/hello/Makefile.am
index d866b6da..847e64d9 100644
--- a/tests/hello/Makefile.am
+++ b/tests/hello/Makefile.am
@@ -4,5 +4,12 @@ noinst_PROGRAMS = hello
 hello_SOURCES = hello.c tp.c ust_tests_hello.h
 hello_LDADD = $(top_builddir)/liblttng-ust/liblttng-ust.la
 
+if LTTNG_UST_BUILD_WITH_LIBDL
+hello_LDADD += -ldl
+endif
+if LTTNG_UST_BUILD_WITH_LIBC_DL
+hello_LDADD += -lc
+endif
+
 noinst_SCRIPTS = run
 EXTRA_DIST = run
diff --git a/tests/hello/Makefile.example b/tests/hello/Makefile.example
deleted file mode 100644
index c983f4c4..00000000
--- a/tests/hello/Makefile.example
+++ /dev/null
@@ -1,8 +0,0 @@
-# Example makefile for build outside of the LTTng-UST tree.
-
-hello:
-	${CC} -O2 -I. -o hello -ldl -llttng-ust hello.c tp.c
-
-.PHONY: clean
-clean:
-	rm -f hello
diff --git a/tests/hello/Makefile.example.bsd b/tests/hello/Makefile.example.bsd
new file mode 100644
index 00000000..607171c2
--- /dev/null
+++ b/tests/hello/Makefile.example.bsd
@@ -0,0 +1,8 @@
+# Example makefile for build outside of the LTTng-UST tree.
+
+hello:
+	${CC} -O2 -I. -o hello -lc -llttng-ust hello.c tp.c
+
+.PHONY: clean
+clean:
+	rm -f hello
diff --git a/tests/hello/Makefile.example.linux b/tests/hello/Makefile.example.linux
new file mode 100644
index 00000000..c983f4c4
--- /dev/null
+++ b/tests/hello/Makefile.example.linux
@@ -0,0 +1,8 @@
+# Example makefile for build outside of the LTTng-UST tree.
+
+hello:
+	${CC} -O2 -I. -o hello -ldl -llttng-ust hello.c tp.c
+
+.PHONY: clean
+clean:
+	rm -f hello