fix smol wrt new glibc version, make mksyms much faster

Makefile

@@ -4,7 +4,7 @@ BINDIR = bin
 SRCDIR = src
 DATADIR = data
 
-COPTFLAGS=-Os -fvisibility=hidden -mpreferred-stack-boundary=2 -fwhole-program \
+COPTFLAGS=-Os -fvisibility=hidden -mpreferred-stack-boundary=3 -fwhole-program \
   -ffast-math -funsafe-math-optimizations -fno-stack-protector -fomit-frame-pointer \
   -fno-exceptions -fno-unwind-tables -fno-asynchronous-unwind-tables
 CXXOPTFLAGS=$(COPTFLAGS) \
@@ -14,7 +14,7 @@ CXXOPTFLAGS=$(COPTFLAGS) \
 ASFLAGS=-f elf -I $(LDRDIR)/
 CFLAGS=-Wall -Wextra -Wpedantic -std=c99 $(COPTFLAGS) -nostartfiles -fno-PIC
 CXXFLAGS=-Wall -Wextra -Wpedantic -std=c++11 $(CXXOPTFLAGS) -nostartfiles -fno-PIC
-LIBS=-lGL -ldl -lc
+LIBS=-lc
 LDFLAGS=--oformat=binary -T ldr/link.ld
 
 
@@ -29,7 +29,7 @@ clean:
 .SECONDARY:
 
 $(OBJDIR)/%.o: $(SRCDIR)/%.c
-	$(CC) $(CFLAGS) -c $^ -o $@
+	$(CC) -m32 $(CFLAGS) -c $^ -o $@
 
 $(OBJDIR)/%.o.syms: $(OBJDIR)/%.o
 	readelf -s $^ | grep UND | sed 1d | awk '{ print $$8 }' > $@
@@ -41,4 +41,4 @@ $(OBJDIR)/header.%.o: $(OBJDIR)/symbols.%.s $(LDRDIR)/header.s $(LDRDIR)/loader.
 	nasm $(ASFLAGS) $< -o $@
 
 $(BINDIR)/%: $(OBJDIR)/%.o $(OBJDIR)/header.%.o
-	$(LD) $(LDFLAGS) $^ -o $@
+	$(LD) -m elf_i386 $(LDFLAGS) $^ -o $@

ldr/header.s

+; vim: set ft=nasm:
 %define ORIGIN 0x400000
 
 extern _size
@@ -31,6 +32,7 @@ header:
         ; e_phentsize
         dw (.segments.load - .segments.dynamic)
 .segments:
+; TODO: .segments.interp
 .segments.dynamic:
         ; {e_phnum: 2, e_shentsize: 0}, p_type: 2 = PT_DYNAMIC
         dd 2

ldr/link.ld

@@ -10,7 +10,7 @@ SECTIONS {
   }
 
   .data : {
-     *(.data .data.* .bss .bss.* .tdata .tdata.* .tbss .tbss.*)
+     *(.data .data.* .tdata .tdata.* .bss .bss.* .tbss .tbss.*)
   }
 
   .dynamic : { *(.dynamic) } :all :dyn

ldr/loader.s

+; vim: set ft=nasm ts=8:
 [section .text]
 
 %define LM_NAME_OFFSET           0x4
 %define LM_NEXT_OFFSET           0xC
 %define LM_ADDR_OFFSET           0
 %define LM_INFO_OFFSET           0x20
-%define LM_NBUCKETS_OFFSET       0x178
-%define LM_GNU_BUCKETS_OFFSET    0x188
-%define LM_GNU_CHAIN_ZERO_OFFSET 0x18C
+%define LM_NBUCKETS_OFFSET       0x17c
+%define LM_GNU_BUCKETS_OFFSET    0x18c
+%define LM_GNU_CHAIN_ZERO_OFFSET 0x190
 
 %define DT_VALUE_OFFSET          0x4
 %define DYN_PTR_OFFSET           0x4
@@ -128,3 +129,4 @@ _start:
 
        call main
        int3
+

ldr/mksyms

 #!/usr/bin/env python3
+
+import glob
 import sys
 import os.path
 import subprocess
@@ -40,19 +42,39 @@ def output_x86(libraries):
 
 
 def get_cc_paths():
-    output = subprocess.check_output(['cc', '-print-search-dirs'], stderr=subprocess.DEVNULL)
+    output = subprocess.check_output(['cc', '-print-search-dirs'],
+                                     stderr=subprocess.DEVNULL)
     paths = {}
     for entry in output.decode('utf-8').splitlines():
         category, path = entry.split(': ', 1)
         path = path.lstrip('=')
-        paths[category] = list(set(os.path.realpath(p) for p in path.split(':') if os.path.isdir(p)))
+        paths[category] = list(set(os.path.realpath(p) \
+                for p in path.split(':') if os.path.isdir(p)))
     return paths
 
-def find_symbol(paths, libraries, symbol):
-    output = subprocess.check_output(['scanelf', '-B', '-F' '%s %S', '-s', '+{}'.format(symbol)] + paths, stderr=subprocess.DEVNULL)
+def is_valid_elf(f):
+    with open(f, 'rb') as ff: return ff.read(4) == b'\x7FELF'
+
+def find_lib(spaths, wanted):
+    for p in spaths:
+        for f in glob.glob(glob.escape(p) + '/lib' + wanted + '.so*'):
+            if os.path.isfile(f) and is_valid_elf(f): return f
+        for f in glob.glob(glob.escape(p) + '/'    + wanted + '.so*'):
+            if os.path.isfile(f) and is_valid_elf(f): return f
+        #for f in glob.glob(glob.escape(p) + '/lib' + wanted + '.a' ): return f
+        #for f in glob.glob(glob.escape(p) + '/'    + wanted + '.a' ): return f
+
+    sys.stderr.write("E: couldn't find library '" + wanted + "'.")
+    sys.exit(1)
+
+def find_libs(spaths, wanted): return map(lambda l: find_lib(spaths, l), wanted)
+
+def find_symbol(libraries, libnames, symbol):
+    output = subprocess.check_output(['scanelf', '-B', '-F' '%s %S', '-s', \
+                '+{}'.format(symbol)] + libraries, stderr=subprocess.DEVNULL)
     for entry in output.decode('utf-8').splitlines():
         sym, soname, path = entry.split(' ', 2)
-        if symbol in sym.split(',') and any(soname.startswith(l) for l in libraries):
+        if symbol in sym.split(',') and any(soname.startswith('lib'+l) for l in libnames):
             return soname
 
 def main():
@@ -63,11 +85,14 @@ def main():
     args = parser.parse_args()
 
     paths = get_cc_paths()
+    libraries=paths['libraries']
+    libnames = args.library
+    libs = list(find_libs(libraries, libnames))
+    sys.stderr.write('libs='+str(libs)+'\n')
     symbols = {}
-    libraries = ['lib{}'.format(l) for l in args.library or []]
 
     for symbol in args.symbols:
-        library = find_symbol(paths['libraries'], libraries, symbol)
+        library = find_symbol(libs, libnames, symbol)
         if not library:
             sys.stderr.write('could not find symbol: {}\n'.format(symbol))
             sys.exit(1)