From 96cf3e4ee49c256b214795e30eb66801bcdcef6d Mon Sep 17 00:00:00 2001
From: johannst <johannes.stoelp@gmail.com>
Date: Mon, 26 Apr 2021 21:41:43 +0200
Subject: Makefile: update comments

---
 04_dynld_nostd/Makefile | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

(limited to '04_dynld_nostd')

diff --git a/04_dynld_nostd/Makefile b/04_dynld_nostd/Makefile
index e72dde8..e4dceb1 100644
--- a/04_dynld_nostd/Makefile
+++ b/04_dynld_nostd/Makefile
@@ -7,9 +7,12 @@ COMMON_CFLAGS := -g -O0 -Wall -Wextra \
 run: main
 	./$<
 
+# Build the example user program.
+#
+# We explicitly set the dynamic linker to `dynld.so` and use the ELF hash table
+# (DT_HASH), as we didn't implement support for the GNU hash table in our
+# dynamic linker.
 main: dynld.so libgreet.so main.c ../lib/libcommon.a
-	@# For now ew only add support for ELF hash tables (DT_HASH).
-	@# Therefore we specify the `hash-style` below.
 	gcc -o $@                                   \
 	    $(COMMON_CFLAGS)                        \
 	    -L$(CURDIR) -lgreet                     \
@@ -18,20 +21,26 @@ main: dynld.so libgreet.so main.c ../lib/libcommon.a
 	    -no-pie \
 	    $(filter %.c %.a, $^)
 
-	readelf -W --dynamic $@
-	readelf -W --program-headers $@
-	objdump --disassemble -j .plt -M intel $@
-	objdump --disassemble=_start -M intel $@
+	#readelf -W --dynamic $@
+	#readelf -W --program-headers $@
+	#objdump --disassemble -j .plt -M intel $@
+	#objdump --disassemble=_start -M intel $@
 
+# Build the example shared library.
+#
+# We explicitly use the ELF hash table (DT_HASH), as we didn't implement
+# support for the GNU hash table in our dynamic linker.
 libgreet.so: libgreet.c
-	@# For now ew only add support for ELF hash tables (DT_HASH).
-	@# Therefore we specify the `hash-style` below.
 	gcc -o $@                 \
 	    $(COMMON_CFLAGS)      \
 	    -fPIC -shared         \
 	    -Wl,--hash-style=sysv \
 	    $^
 
+# Build the dynamic linker.
+#
+# We assert that the dynamic linker doesn't contain any relocations as we
+# didn't implement support to resolve its own relocations.
 dynld.so: dynld.S dynld.c ../lib/libcommon.a
 	gcc -o $@                          \
 	    $(COMMON_CFLAGS)               \
@@ -41,9 +50,8 @@ dynld.so: dynld.S dynld.c ../lib/libcommon.a
 	    -Wl,--no-allow-shlib-undefined \
 	    $^
 
-	@if readelf -W -S $@ | grep plt >& /dev/null; then \
-		echo "ERROR: $@ contains PLT while we don't support relocation calls in $@!"; \
-		echo "       All function calls in $@ must be statically resolved!"; \
+	@if ! readelf -r $@ | grep 'There are no relocations in this file' >& /dev/null; then \
+		echo "ERROR: $@ contains relocations while we don't support relocations in $@!"; \
 		exit 1; \
 	fi
 
-- 
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