// gcc -Wall -I/usr/include/rpm rpmfile.c -lrpm -o rpmfile
#include <error.h>
#include <stdlib.h>
#include <string.h>
#include <rpmlib.h>

struct cpio_header
{
	char magic[6];
	char inode[8];
	char mode[8];
	char uid[8];
	char gid[8];
	char nlink[8];
	char mtime[8];
	char filesize[8];
	char dev_major[8];
	char dev_minor[8];
	char rdev_major[8];
	char rdev_minor[8];
	char namesize[8];
	char checksum[8];
};

int num8(char *s)
{
	char c = s[8];
	s[8] = 0;
	int n = strtoul(s, NULL, 16);
	s[8] = c;
	return n;
}

FD_t open_payload(const char *fname)
{
	FD_t fd = Fopen(fname, "r.ufdio");
	if (Ferror(fd))
		error(1, 0, "%s: %s", fname, Fstrerror(fd));
	
	Header h; int isSource;
	if (rpmReadPackageHeader(fd, &h, &isSource, NULL, NULL))
		error(1, 0, "%s: %s", fname, "bad RPM header");
	
	char *method;
	if (headerGetEntry(h, RPMTAG_PAYLOADCOMPRESSOR, NULL, (void **) &method, NULL))
		method = "gzip";
	
	char *type = "r";
	if (strcmp(method, "gzip") == 0)
		type = "r.gzdio";
	if (strcmp(method, "bzip2") == 0)
		type = "r.bzdio";

	FD_t zfd = Fdopen(fd, type);
	if (Ferror(zfd))
		error(1, 0, "%s: %s", fname, Fstrerror(zfd));
	if (fd != zfd)
		Fclose(fd);

	return zfd;
}

void rpmfile(const char *fname)
{
	FD_t fd = open_payload(fname);
	
	while (1) {
		size_t n;
		struct cpio_header h;
		n = Fread(&h, sizeof(h), 1, fd);
		if (n != 1)
			error(1, 0, "%s: %s", fname, "bad cpio header");
		if (strncmp(h.magic, "070701", 6))
			error(1, 0, "%s: %s", fname, "bad cpio magic");

		char path[PATH_MAX];
		int len = num8(h.namesize);
		n = Fread(path, len, 1, fd);
		if (n != 1)
			error(1, 0, "%s: %s", fname, "bad cpio namesize");
		if (strcmp(path, "TRAILER!!!") == 0)
			break;

		char buf[4096];
		int size = num8(h.filesize);
		int toread = (size > sizeof(buf)) ? sizeof(buf) : size;
		int toseek = size - toread;
		n = 1;
		if (toread)
			n = Fread(buf, toread, 1, fd);
		if (toseek)
			n += Fseek(fd, toseek, SEEK_CUR);
		if (n != 1)
			error(1, 0, "%s: %s", fname, "bad cpio filesize");
			
		int mode = num8(h.mode);
		printf("%s\t%s\t0%o\n", fname, path, mode);
		
		/* TODO: zero padded? how do I seek ? */
		break;
	}
	Fclose(fd);
}

int main(int argc, char *argv[])
{
	while (--argc > 0)
		rpmfile(*++argv);
	return 0;
}