#include <sys/stat.h>
#include <fcntl.h>
#include <gelf.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

int main(int argc, char **argv)
{
	Elf		*e;
	Elf_Scn		*scn;
	Elf_Data	*data;
	GElf_Shdr	 shdr;
	char		*name;
	int		 i;
	int		 fd;
	size_t		 shstrndx;
	struct stat	 sb;
	char		 x;
	uint32_t	 nbuckets;
	uint32_t	 symndx;
	uint32_t	 maskwords;
	uint32_t	 shift2;
	uint32_t	*header, *bm32;
	uint64_t	*bm64;
	uint32_t	*buckets;
	uint32_t	*chains;
	unsigned char	*raw, *rawlimit;

	if (argc != 2) {
		fprintf(stderr, "usage: gnuhash_dump file\n");
		exit(1);
	}

	if (elf_version(EV_CURRENT) == EV_NONE)
		errx(EX_SOFTWARE, "ELF library initialization failed: %s",
		     elf_errmsg(-1));

	if ((fd = open(argv[1], O_RDONLY)) < 0 ||
	    fstat(fd, &sb) < 0)
		err(EX_NOINPUT, "%s", argv[1]);

	if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL)
		errx(EX_SOFTWARE, "elf_begin() failed: %s",
		     elf_errmsg(-1));

	if (elf_kind(e) != ELF_K_ELF)
		errx(EX_DATAERR, "not an elf file");

	if (elf_getshstrndx(e, &shstrndx) == 0)
		errx(EX_SOFTWARE, "elf_getshstrndx failed: %s",
		     elf_errmsg(-1));

	scn = NULL;
	while ((scn = elf_nextscn(e, scn)) != NULL) {
		if (gelf_getshdr(scn, &shdr) != &shdr)
			errx(EX_SOFTWARE, "elf_getshdr failed: %s",
			     elf_errmsg(-1));
		if ((name = elf_strptr(e, shstrndx, shdr.sh_name)) == NULL)
			errx(EX_SOFTWARE, "elf_strptr failed: %s",
			     elf_errmsg(-1));
		if (strcmp(name, ".gnu.hash") != 0)
			continue;

		printf("section: %s\n\n", name);
		data = NULL;
		while ((data = elf_getdata(scn, data)) != NULL) {
			printf("data->d_align = %u\n", data->d_align);
			printf("data->d_size = %u\n", data->d_size);
			printf("data->d_type = %u\n", data->d_type);
			printf("\n");
			header = data->d_buf;
			nbuckets = header[0];
			symndx = header[1];
			maskwords = header[2];
			shift2 = header[3];
			printf("nbuckets=%u\n", nbuckets);
			printf("symndx=%u\n", symndx);
			printf("maskwords=%u\n", maskwords);
			printf("shift2=%u\n", shift2);
			if (gelf_getclass(e) == ELFCLASS64) {
				bm64 = (uint64_t *) (data->d_buf + 4 * sizeof(uint32_t));
				for(i = 0; i < maskwords; i++) {
					printf("bm64[%d]=%u\n", i, bm64[i]);
				}
				buckets = (uint32_t *) &bm64[i];
			} else {
				bm32 = (uint32_t *) (data->d_buf + 4 * sizeof(uint32_t));
				for(i = 0; i < maskwords; i++) {
					printf("bm32[%d]=%u\n", i, bm32[i]);
				}
				buckets = &bm32[i];
			}
			for (i = 0; i < nbuckets; i++) {
				printf("buckets[%d]=%u\n", i, buckets[i]);
			}
			chains = &buckets[i];
			i = 0;
			while ((char *)chains < ((char *)data->d_buf + data->d_size))
				printf("chains[%d]=%u\n", i++, *chains++);

		}

		while ((data = elf_rawdata(scn, data)) != NULL) {
			printf("\n");
			printf("dump of raw data:\n");
			raw = data->d_buf;
			rawlimit = raw + data->d_size;
			i = 0;
			while (raw < rawlimit) {
				printf("0x%02X ", *raw++);
				if (++i % 16 == 0)
					printf("\n");
			}
		}
	}
	
	return (0);
}