Makefile_v1,README.md: major update with improved diagnostics

Makefile_v1

@@ -12,19 +12,20 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-# Optional OPENSSL_DIR defines absolute or relative (to ../) path to OpenSSL installation
-# Optional OPENSSL_LIB defines where to find the OpenSSL library installation (default: OPENSSL_DIR/lib).
+# Optional OPENSSL_DIR defines where to find the OpenSSL installation
+#   with header files at include/openssl (default: will try, e.g., /usr).
+# Optional OPENSSL_LIB defines where to find the OpenSSL libraries
+#   (default: will try, e.g., OPENSSL_DIR/lib).
 # Optional CFLAGS and LDFLAGS are appended by local settings.
 # Optional DEBUG_FLAGS may set to prepend to local CFLAGS and LDFLAGS (default see below).
 # Builds are done in release mode if optional NDEBUG is defined.
-# Optional OUT_DIR defines absolute or relative (to ./) path where to place the library.
+# Optional OUT_DIR defines where to place the resulting library (default: '.').
 # Optional DESTDIR defines a prefix for the installation target directories.
+# All paths may be absolute or relative to the directory containing this Makefile.
 
 ROOTFS ?= $(DESTDIR)$(prefix)
 
-ifeq ($(OUT_DIR),)
-     override OUT_DIR = .
-endif
+override OUT_DIR ?= .
 
 VERSION=2.0
 # must be kept in sync with debian/changelog and CMakeLists.txt
@@ -33,9 +34,13 @@ VERSION=2.0
 
 SHELL=bash # This is needed for supporting extended file name globbing
 
-ifeq ($(OS),Windows_NT)
+# https://stackoverflow.com/questions/714100/os-detecting-makefile
+ifeq ($(OS),Windows_NT) # strange but apparently this string is used also for all later versions
+    OS=Windows
+    USERS="\\Users\\"
     EXE=.exe
     DLL=.dll
+    SONAME=
     OBJ=.obj
     LIB=bin
 else
@@ -44,26 +49,68 @@ else
     LIB=lib
     ifeq ($(shell uname -s),Darwin)
         OS=MacOS
+        USERS="/Users/"
         DLL=.dylib
         SONAME=install_name,@rpath/
     else # assuming Linux
+        USERS="/home/"
         DLL=.so
         SONAME=soname,
     endif
 endif
 
-ifeq ($(OPENSSL_DIR),)
-    OPENSSL_DIR=$(ROOTFS)/usr
+ifneq ($(filter-out doc install uninstall clean clean_config clean_all clean_uta clean_deb,$(MAKECMDGOALS)),)
+ifeq ($(OPENSSL_DIR),) # for convenience, use heuristics to determine OPENSSL_DIR
+    ifeq ($(OS),MacOS)
+        SYSTEM_INCLUDE_OPENSSL=/opt/homebrew/include/openssl # usually symlink
+    else # TODO for Windows
+        SYSTEM_INCLUDE_OPENSSL=/usr/include/openssl
+    endif
+    OPENSSL_INCLUDE_DIR = $(realpath $(SYSTEM_INCLUDE_OPENSSL))
+    override OPENSSL_DIR = $(realpath $(OPENSSL_INCLUDE_DIR)/../..)
 endif
-ifeq ($(shell echo $(OPENSSL_DIR) | grep "^/"),)
-# $(OPENSSL_DIR) is relative path, assumed relative to ../
-    OPENSSL=../$(OPENSSL_DIR)
-    OPENSSL_LIB ?= ../$(OPENSSL_DIR)
-else
-# $(OPENSSL_DIR) is absolute path
-    OPENSSL=$(OPENSSL_DIR)
-    OPENSSL_LIB ?= $(OPENSSL_DIR)
+ifneq ($(OPENSSL_DIR),) # due to the above, always true
+    LIB_NAME_PATTERN=libcrypto*$(DLL)*
+    ifeq ($(realpath $(OPENSSL_DIR)),)
+        $(error OPENSSL_DIR appears to be an invalid path: $(OPENSSL_DIR))
+    endif
+    override OPENSSL_DIR := $(realpath $(OPENSSL_DIR))
+
+    ifeq ($(OPENSSL_LIB),) # for convenience, use heuristics to determine OPENSSL_LIB
+        override OPENSSL_LIB = $(OPENSSL_DIR)/$(LIB)
+        ifeq ($(wildcard $(OPENSSL_LIB)/$(LIB_NAME_PATTERN)),)
+            # $(warning Warning: cannot find OpenSSL libraries at determined location $(OPENSSL_LIB), now trying OPENSSL_DIR)
+            override OPENSSL_LIB = $(OPENSSL_DIR)
+            ifeq ($(wildcard $(OPENSSL_LIB)/$(LIB_NAME_PATTERN)),)
+                ifeq ($(OS),Linux)
+	            ifeq ($(findstring $(USERS),$(OPENSSL_FULL_DIR)),)
+                        override OPENSSL_LIB = $(wildcard /lib/*linux-gnu*)
+                        # $(warning Warning: cannot find OpenSSL libraries at $(OPENSSL_DIR), now trying $(OPENSSL_LIB))
+                    endif
+                endif
+            endif
+        endif
+    else
+        ifeq ($(wildcard $(OPENSSL_LIB)/$(LIB_NAME_PATTERN)),)
+            # $(warning Warning: cannot find OpenSSL libraries at given OPENSSL_LIB $(OPENSSL_LIB), now trying OPENSSL_DIR)
+            override OPENSSL_LIB = $(OPENSSL_DIR)
+        endif
+    endif
+    # ifeq ($(findstring $(USERS),$(OPENSSL_FULL_DIR)),)
+    #     $(warning [DEBUG] OPENSSL_DIR is assumed to be an installation directory)
+    # else
+    #     $(warning [DEBUG] OPENSSL_DIR is assumed to be a local build directory)
+    # endif
+    ifeq ($(wildcard $(OPENSSL_LIB)/$(LIB_NAME_PATTERN)),)
+        $(error Error: cannot find OpenSSL library $(LIB_NAME_PATTERN) at $(OPENSSL_LIB)/)
+    endif
+    override OPENSSL_LIB := $(realpath $(OPENSSL_LIB))
+endif
+ifeq ($(wildcard $(OPENSSL_DIR)/include/openssl),)
+    $(error cannot find directory '$(OPENSSL_DIR)/include/openssl', check OPENSSL_DIR variable)
 endif
+endif # neq ($(filter-out doc install uninstall clean clean_config clean_all clean_uta clean_deb,$(MAKECMDGOALS)),)
+
 
 ################################################################################
 # Basic definitions targeted at debugging
@@ -73,10 +120,10 @@ endif
 ################################################################################
 
 ifdef NDEBUG
-    DEBUG_FLAGS ?= -O2
+    override DEBUG_FLAGS ?= -O2
     override DEBUG_FLAGS += -DNDEBUG=1 -Werror
 else
-    DEBUG_FLAGS ?= -g -O0 -fsanitize=address -fsanitize=undefined -fno-sanitize-recover=all # not every compiler(version) supports -Og
+    override DEBUG_FLAGS ?= -g -O0 -fsanitize=address -fsanitize=undefined -fno-sanitize-recover=all # not every compiler(version) supports -Og
 endif
 override CFLAGS += $(DEBUG_FLAGS) \
  -Wall -Woverflow -Wextra -Wswitch -Wmissing-prototypes -Wstrict-prototypes \
@@ -94,7 +141,7 @@ override CFLAGS += -pedantic -DPEDANTIC
 ################################################################################
 
 CC ?= gcc
-OUTLIB_=libsecutils
+override OUTLIB_= libsecutils
 OUTLIB=$(OUTLIB_)$(DLL)
 ifeq ($(OS),MacOS)
     OUTLIBV=$(OUTLIB_).$(VERSION)$(DLL)
@@ -109,7 +156,7 @@ DEST_DOC=$(DEST_PRE)/share/doc/libsecutils-dev
 OUTBIN=icvutil$(EXE)
 DEST_BIN=$(DEST_PRE)/bin
 LOCAL_CFLAGS= -fPIC # -std=gnu90 TODO clean up code and re-enable flag
-override CFLAGS += -isystem $(OPENSSL)/include# # # use of -isystem is critical for selecting wanted OpenSSL version
+override CFLAGS += -isystem $(OPENSSL_DIR)/include# # use of -isystem is critical for selecting wanted OpenSSL version
 override CFLAGS += -Isrc/libsecutils/include
 override CFLAGS += -Isrc/libsecutils/include/secutils
 ifneq ($(SECUTILS_USE_UTA),)
@@ -120,12 +167,9 @@ ifneq ($(SECUTILS_USE_ICV),)
 endif
 
 override LDFLAGS += $(DEBUG_FLAGS) # needed for -fsanitize=...
-override LDFLAGS += -L $(OPENSSL_LIB) -L $(OPENSSL)
+override LDFLAGS += -L $(OPENSSL_LIB)
 ifeq ($(DEB_TARGET_ARCH),) # not during Debian packaging
   override LDFLAGS += -Wl,-rpath,$(OPENSSL_LIB)
-  ifneq ($(OPENSSL_LIB),$(OPENSSL))
-    override LDFLAGS += -Wl,-rpath,$(OPENSSL)
-  endif
 endif
 ifneq ($(SECUTILS_USE_UTA),)
     override LDFLAGS += -luta
@@ -173,6 +217,11 @@ OBJS := $(patsubst %.c,$(BUILDDIR)/%$(OBJ),$(notdir $(wildcard src/libsecutils/s
 # Default target
 all: build_all doc
 
+ifneq ($(findstring build_only,$(MAKECMDGOALS)),)
+    $(info Build info: source directory is '$(PWD)')
+    $(info detected OpenSSL base directory '$(OPENSSL_DIR)')
+    $(info detected OpenSSL lib  directory '$(OPENSSL_LIB)')
+endif
 build_only: $(OUT_DIR)/$(OUTLIB)
 
 build:

README.md

@@ -1,4 +1,4 @@
-# libsecutils
+# libSecUtils
 
 <img src="libsecutils.svg" width="200">
 
@@ -76,7 +76,7 @@ including the C header files needed for development
 
 By default any OpenSSL installation available on the system is used.
 Set the optional environment variable `OPENSSL_DIR` to specify the
-absolute (or relative to `../`) path of the OpenSSL installation to use, e.g.:
+absolute or relative path of the OpenSSL installation to use, e.g.:
 ```
 export OPENSSL_DIR=/usr/local
 ```
@@ -85,6 +85,9 @@ In case its libraries are in a different location, set also `OPENSSL_LIB`, e.g.:
 export OPENSSL_LIB=$OPENSSL_DIR/lib
 ```
 
+For all environment variables specifying a directory, relative paths such as `.`
+are interpreted relative to the libSecUtils source directory.
+
 Use of the UTA library can be enabled
 by setting the environment variable `SECUTILS_USE_UTA`.