/*

 * Common "util" functions

 * This file is part of the dmidecode project.

 *

 *   Copyright (C) 2002-2018 Jean Delvare <jdelvare@suse.de>

 *

 *   This program is free software; you can redistribute it and/or modify

 *   it under the terms of the GNU General Public License as published by

 *   the Free Software Foundation; either version 2 of the License, or

 *   (at your option) any later version.

 *

 *   This program is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *   GNU General Public License for more details.

 *

 *   You should have received a copy of the GNU General Public License

 *   along with this program; if not, write to the Free Software

 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA

 *

 *   For the avoidance of doubt the "preferred form" of this code is one which

 *   is in an open unpatent encumbered format. Where cryptographic key signing

 *   forms part of the process of creating an executable the information

 *   including keys needed to generate an equivalently functional executable

 *   are deemed to be part of the source code.

 */

#include <sys/types.h>

#include <sys/stat.h>

#include "config.h"

#ifdef USE_MMAP

#include <sys/mman.h>

#ifndef MAP_FAILED

#define MAP_FAILED ((void *) -1)

#endif /* !MAP_FAILED */

#endif /* USE MMAP */

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <fcntl.h>

#include <errno.h>

#include "types.h"

#include "util.h"

static int myread(int fd, u8 *buf, size_t count, const char *prefix)

{

	ssize_t r = 1;

	size_t r2 = 0;

	while (r2 != count && r != 0)

	{

		r = read(fd, buf + r2, count - r2);

		if (r == -1)

		{

			if (errno != EINTR)

			{

				perror(prefix);

				return -1;

			}

		}

		else

			r2 += r;

	}

	if (r2 != count)

	{

		fprintf(stderr, "%s: Unexpected end of file\n", prefix);

		return -1;

	}

	return 0;

}

int checksum(const u8 *buf, size_t len)

{

	u8 sum = 0;

	size_t a;

	for (a = 0; a < len; a++)

		sum += buf[a];

	return (sum == 0);

}

/*

 * Reads all of file from given offset, up to max_len bytes.

 * A buffer of at most max_len bytes is allocated by this function, and

 * needs to be freed by the caller.

 * This provides a similar usage model to mem_chunk()

 *

 * Returns a pointer to the allocated buffer, or NULL on error, and

 * sets max_len to the length actually read.

 */

void *read_file(off_t base, size_t *max_len, const char *filename)

{

	struct stat statbuf;

	int fd;

	u8 *p;

	/*

	 * Don't print error message on missing file, as we will try to read

	 * files that may or may not be present.

	 */

	if ((fd = open(filename, O_RDONLY)) == -1)

	{

		if (errno != ENOENT)

			perror(filename);

		return NULL;

	}

	/*

	 * Check file size, don't allocate more than can be read.

	 */

	if (fstat(fd, &statbuf) == 0)

	{

		if (base >= statbuf.st_size)

		{

			fprintf(stderr, "%s: Can't read data beyond EOF\n",

				filename);

			p = NULL;

			goto out;

		}

		if (*max_len > (size_t)statbuf.st_size - base)

			*max_len = statbuf.st_size - base;

	}

	if ((p = malloc(*max_len)) == NULL)

	{

		perror("malloc");

		goto out;

	}

	if (lseek(fd, base, SEEK_SET) == -1)

	{

		fprintf(stderr, "%s: ", filename);

		perror("lseek");

		goto err_free;

	}

	if (myread(fd, p, *max_len, filename) == 0)

		goto out;

err_free:

	free(p);

	p = NULL;

out:

	if (close(fd) == -1)

		perror(filename);

	return p;

}

static void safe_memcpy(void *dest, const void *src, size_t n)

{

#ifdef USE_SLOW_MEMCPY

	size_t i;

	for (i = 0; i < n; i++)

		*((u8 *)dest + i) = *((const u8 *)src + i);

#else

	memcpy(dest, src, n);

#endif

}

/*

 * Copy a physical memory chunk into a memory buffer.

 * This function allocates memory.

 */

void *mem_chunk(off_t base, size_t len, const char *devmem)

{

	void *p;

	int fd;

#ifdef USE_MMAP

	struct stat statbuf;

	off_t mmoffset;

	void *mmp;

#endif

	if ((fd = open(devmem, O_RDONLY)) == -1)

	{

		perror(devmem);

		return NULL;

	}

	if ((p = malloc(len)) == NULL)

	{

		perror("malloc");

		goto out;

	}

#ifdef USE_MMAP

	if (fstat(fd, &statbuf) == -1)

	{

		fprintf(stderr, "%s: ", devmem);

		perror("stat");

		goto err_free;

	}

	/*

	 * mmap() will fail with SIGBUS if trying to map beyond the end of

	 * the file.

	 */

	if (S_ISREG(statbuf.st_mode) && base + (off_t)len > statbuf.st_size)

	{

		fprintf(stderr, "mmap: Can't map beyond end of file %s\n",

			devmem);

		goto err_free;

	}

#ifdef _SC_PAGESIZE

	mmoffset = base % sysconf(_SC_PAGESIZE);

#else

	mmoffset = base % getpagesize();

#endif /* _SC_PAGESIZE */

	/*

	 * Please note that we don't use mmap() for performance reasons here,

	 * but to workaround problems many people encountered when trying

	 * to read from /dev/mem using regular read() calls.

	 */

	mmp = mmap(NULL, mmoffset + len, PROT_READ, MAP_SHARED, fd, base - mmoffset);

	if (mmp == MAP_FAILED)

		goto try_read;

	safe_memcpy(p, (u8 *)mmp + mmoffset, len);

	if (munmap(mmp, mmoffset + len) == -1)

	{

		fprintf(stderr, "%s: ", devmem);

		perror("munmap");

	}

	goto out;

try_read:

#endif /* USE_MMAP */

	if (lseek(fd, base, SEEK_SET) == -1)

	{

		fprintf(stderr, "%s: ", devmem);

		perror("lseek");

		goto err_free;

	}

	if (myread(fd, p, len, devmem) == 0)

		goto out;

err_free:

	free(p);

	p = NULL;

out:

	if (close(fd) == -1)

		perror(devmem);

	return p;

}

int write_dump(size_t base, size_t len, const void *data, const char *dumpfile, int add)

{

	FILE *f;

	f = fopen(dumpfile, add ? "r+b" : "wb");

	if (!f)

	{

		fprintf(stderr, "%s: ", dumpfile);

		perror("fopen");

		return -1;

	}

	if (fseek(f, base, SEEK_SET) != 0)

	{

		fprintf(stderr, "%s: ", dumpfile);

		perror("fseek");

		goto err_close;

	}

	if (fwrite(data, len, 1, f) != 1)

	{

		fprintf(stderr, "%s: ", dumpfile);

		perror("fwrite");

		goto err_close;

	}

	if (fclose(f))

	{

		fprintf(stderr, "%s: ", dumpfile);

		perror("fclose");

		return -1;

	}

	return 0;

err_close:

	fclose(f);

	return -1;

}

/* Returns end - start + 1, assuming start < end */

u64 u64_range(u64 start, u64 end)

{

	u64 res;

	res.h = end.h - start.h;

	res.l = end.l - start.l;

	if (end.l < start.l)

		res.h--;

	if (++res.l == 0)

		res.h++;

	return res;

}