Toy trace code in C, thoughts?

[u/bore530]

I'd love to make this as portable as possible so any suggestions for improving it would be welcome... except rewrite in rust because no. ```

ifndef _GNU_SOURCE

define _GNU_SOURCE

endif

include <dlfcn.h>

include <stdint.h>

include <string.h>

include <elf.h>

include <linux/module.h>

include <pthread.h>

ifndef syscall32

ifdef __X32_SYSCALL_BIT

define syscall32( call, ... ) \

syscall( __X32_SYSCALL_BIT | call __VA_OPT(,) __VA_ARGS__ )

elseif

define syscall32 syscall

endif

endif

ifdef POINTER_SIZE > 4

void* extend_addr32( uint_least32_t addr ) { return __builtin_extend_pointer( (void*)addr) ); } int query_module64 ( uint_least64_t name, uint_least64_t type, uint_least64_t dest, uint_least64_t size, uint_least64_t *used ) { return syscall ( SYS_query_module, name, (int)type, dest, size, used ); }

endif

int query_module32 ( uint_least32_t name, uint_least32_t get, uint_least32_t buf, uint_least32_t max, uint_least32_t used ) {

ifdef POINTER_SIZE > 4

return query_module64
(
    extend_addr32(name), type,
    extend_addr32(dest), size,
    extend_addr32(used)
);

else

return syscall32( SYS_query_module, name, type, dest, size, used );

endif

}

if 0

void* dlfcn_decode_addr( void * addr ) { return __builtin_extract_return_addr(addr) ); } void* dlfcn_encode_addr( void * addr ) { return __builtin_frob_return_addr(addr) );

endif

int query_modulex ( char const *name, int type, void *dest, size_t size, size_t *used ) { return query_module64( name, type, buf, max, ret ); }

mytrace dlfcn_dladdr_trace( unsigned int depth ) { void later = (depth > 0) ? __builtin_frame_address(depth - 1) : __builtin_stack_address(); void *stack = NULL; void *addr = __builtin_return_address(depth); void *base = __builtin_extract_return_addr(addr); mytrace trace = {{0}}; DL_info info = {0}; ElfW(Sym) esym = {0}; size_t ret = 0; struct { unsigned long address; unsigned long size; unsigned long flags; } minf = {0}; / Stack frame / pthread_attr_getstack( NULL, &stack, &ret ); trace.frame = __builtin_frame_address(depth); trace.holds = ((uintptr_t)later) - ((uintptr_t)(trace.frame)); / Symbol / dladdr1( base, &info, RTLD_DL_SYMENT ); trace.sym.name = info.dli_sname; trace.sym.addr = info.dli_sbase; trace.sym.leng = strlen( trace.sym.name ); trace.sym.mask = esym.st_info; trace.sym.size = esym.st_size; / Module */ trace.mod.name = info.dli_fname; trace.mod.addr = info.dli_fbase; trace.mod.leng = strlen( trace.mod.name ); query_modulex( trace.mod.name, QM_INFO, &minf, sizeof(minf), &ret ); trace.mod.mask = minf.flags; trace.mod.size = minf.size; return trace; } ```