#!/bin/sh
# $FreeBSD: stable/11/tools/build/check-links.sh 294357 2016-01-19 22:42:16Z bdrewery $

proc libkey {
	setglobal libkey = ""lib_symbols_$1""
	setglobal patterns = '[.+,/-]'
	setglobal replacement = '_'
	while : {
		match " $(libkey) " {
			with *${patterns}*
				setglobal libkey = ""$(libkey%%${patterns}*)$(replacement)$(libkey#*${patterns})""
				
			with *
				break
				
		}
	}
	return 0
}

proc usage {
	cat << """
usage: $0 [-Uv] [-L LD_LIBRARY_PATH] file
       -L:       Specify an alternative LD_LIBRARY_PATH for the library resolution.
       -U:       Skip looking for unresolved symbols.
       -v:       Show which library each symbol is resolved to.
"""
	exit 0
}

setglobal ret = '0'
setglobal CHECK_UNRESOLVED = '1'
setglobal VERBOSE_RESOLVED = '0'
while getopts "L:Uv" flag {
	match $(flag) {
		with L setglobal LIB_PATH = $(OPTARG) 
		with U setglobal CHECK_UNRESOLVED = '0' 
		with v setglobal VERBOSE_RESOLVED = '1' 
		with * usage 
	}
}
shift $shExpr('OPTIND-1')

if ! test -f $1 {
	echo "No such file or directory: $1" > !2
	exit 1
}

setglobal mime = $[file -L --mime-type $1]
setglobal isbin = '0'
match $mime {
with *application/x-executable setglobal isbin = '1' 
with *application/x-sharedlib
with * echo "Not an elf file" > !2 ; exit 1
}

# Gather all symbols from the target
setglobal unresolved_symbols = $[nm -u -D --format=posix $1 | awk '$2 == "U" {print $1}' | tr '\n' ' ]
test $(isbin) -eq 1 && setglobal bss_symbols = $[nm -D --format=posix $1 | awk '$2 == "B" && $4 != "" {print $1}' | tr '\n' ' ]
if test -n $(LIB_PATH) {
	for libc in [/lib/libc.so.*] {
		setglobal LDD_ENV = ""LD_PRELOAD=$(libc)""
	}
	setglobal LDD_ENV = ""$(LDD_ENV) LD_LIBRARY_PATH=$(LIB_PATH)""
}

setglobal ldd_libs = $[env $(LDD_ENV) ldd $[realpath $1] | awk '{print $1 ":" $3}]

# Check for useful libs
setglobal list_libs = ''
setglobal resolved_symbols = ''
for lib in [$[readelf -d $1 | awk '$2 ~ /\(?NEEDED\)?/ { sub(/\[/,"",$NF); sub(/\]/,"",$NF); print $NF }]] {
	echo -n "checking if $lib is needed: "
	if test -n $(lib##/*) {
		for libpair in [$(ldd_libs)] {
			match $(libpair) {
				with ${lib}:* setglobal libpath = $(libpair#*:) && break 
			}
		}
	} else {
		setglobal libpath = $(lib)
	}
	setglobal list_libs = ""$list_libs $lib""
	setglobal foundone = ''
	setglobal lib_symbols = $[nm -D --defined-only --format=posix $(libpath) | awk '$2 ~ /C|R|D|T|W|B|V/ {print $1}' | tr '\n' ' ]
	if test $(CHECK_UNRESOLVED) -eq 1 {
		# Save the global symbols for this lib
		libkey $(lib)
		setvar $(libkey) $(lib_symbols)
	}
	for fct in [$(lib_symbols)] {
		match " $(unresolved_symbols) $(bss_symbols) " {
			with *\ ${fct}\ * setglobal foundone = $(fct) && break 
		}
	}
	if test -n $(foundone) {
		echo "yes... $(foundone)"
	} else {
		echo "no"
		setglobal ret = '1'
	}
}

if test $(CHECK_UNRESOLVED) -eq 1 {
	# Add in crt1 symbols
	setglobal list_libs = ""$(list_libs) crt1.o""
	setglobal lib_symbols = $[nm --defined-only --format=posix "/usr/lib/crt1.o" | awk '$2 ~ /C|R|D|T|W|B|V/ {print $1}' | tr '\n' ' ]
	# Save the global symbols for this lib
	libkey "crt1.o"
	setvar $(libkey) $(lib_symbols)

	# Now search libs for all symbols and report missing ones.
	for sym in [$(unresolved_symbols)] {
		setglobal found = '0'
		for lib in [$(list_libs)] {
			libkey $(lib)
			eval "lib_symbols=\"\${$(libkey)}\""
			# lib_symbols now contains symbols for the lib.
			match " $(lib_symbols) " {
				with *\ ${sym}\ *
					test $(VERBOSE_RESOLVED) -eq 1 &&
					    echo "Resolved symbol $(sym) from $(lib)"
					setglobal found = '1'
					break
					
			}
		}
		if test $found -eq 0 {
			echo "Unresolved symbol $sym"
			setglobal ret = '1'
		}
	}
}

exit ${ret}