#define _POSIX_C_SOURCE 200809L

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

#include "zpm.h"
#include "elf.h"

#include "sha256.h"

/* flags 0, close mmap, flags 1, return mmap fd */
int zpm_hash(char *path, char *hash, uint32_t flags) {
	int fd;
	void *content;
	struct stat sbuf;
	struct sha256_state md;
	int j;
	unsigned char tmp[32];

	/* mmap the file */
	fd = open(path, O_RDONLY);
	if (fd == -1) {
		fprintf(stderr, "%s can't open %s: %s\n", __FUNCTION__, path,strerror(errno));
		return 0;
	}
	if (fstat(fd, &sbuf) == -1) {
		fprintf(stderr, "%s can't fstat %s: %s\n", __FUNCTION__, path,strerror(errno));
		return 0;
	}
	/* not a regular file? */
	if (!S_ISREG(sbuf.st_mode)) {
		/* TODO this is ok, just stored differently */
		fprintf(stderr, "%s non-regular files unsupported %s\n", __FUNCTION__, path);
		return 0;
	}

	content = mmap(0, sbuf.st_size, PROT_READ,MAP_PRIVATE, fd, 0);
	close(fd);
	if (!content) {
		fprintf(stderr, "%s can't mmap %s: %s\n", __FUNCTION__, path,strerror(errno));
		return 0;
	}

	/* get hash */
	sha256_init(&md);
	sha256_process(&md, content, sbuf.st_size);
	sha256_done(&md, tmp);
	for (j=0;j<32;j++) {
		sprintf(hash+j*2, "%02x", (unsigned)tmp[j]);
	}
	hash[64] = 0;
	munmap(content, sbuf.st_size);
	return flags ? fd : 1;
}