How to undo strip - i.e. add symbols back to stripped binary
For those tools that do not support separate files for debug information, you can glue the debug sections back to the original binary.
You can do something along these lines, for example:
First build a small program that efficiently extracts an arbitrary chunk from a file
(note that
dd
will not do this efficiently as we'd have to usebs=1
to support an arbitrary offset and length, andobjcopy -O binary
does not copy sections that are notALLOC, LOAD
※)cat <<EOF | gcc -xc -o ./mydd -#include <errno.h>#include <fcntl.h>#include <stdio.h>#include <stdlib.h>#include <sys/stat.h>#include <unistd.h>#include <macros.h>char buf[1024*1024];int main(int argc, char** argv) { char *fin, *fout; int fdin, fdout; off_t off; size_t len; ssize_t rd; int status; if (argc != 5) { fprintf(stderr, "Usage: %s fin skip count fout\n", argv[0]); return 1; } fin = argv[1]; off = strtoul(argv[2], NULL, 0); len = strtoul(argv[3], NULL, 0); fout = argv[4]; fdin = -1; fdout = -1; if ((fdin = open(fin, O_RDONLY)) < 0) { status = errno; perror(fin); } else if ((fdout = open(fout, O_WRONLY|O_TRUNC|O_CREAT, 0660)) < 0) { status = errno; perror(fout); } else if (lseek(fdin, off, SEEK_SET) == (off_t)-1) { status = errno; perror("Seeking input"); } else { while (len > 0 && (rd = read(fdin, buf, min(len, sizeof(buf)))) > 0) { if (write(fdout, buf, rd) != rd) { /*don't bother with partial writes or EINTR/EAGAIN*/ status = errno; perror(fin); break; } len -= rd; } if (rd < 0) { status = errno; perror(fin); } } if (fdin >= 0) close(fdin); if (fdout >= 0) close(fdout); return status;}EOF
Finally, extract the
.debug
sections and glue them to the stripped binary.objcopy ` objdump -h program.dbg | awk '$2~/^\.debug/' | while read idx name size vma lma off algn ; do echo "$name" >&2 echo " --add-section=$name=$name.raw" ./mydd program.dbg 0x$off 0x$size $name".raw" done` program program_with_dbg
Valgrind supports separate debug files, so you should use the answer here, and valgrind should work properly with the externalized debug file.