host/lib/host_misc.c

/* Copyright 2011 The ChromiumOS Authors
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 *
 * Host functions for verified boot.
 */

/* TODO: change all 'return 0', 'return 1' into meaningful return codes */

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "host_common.h"

char* StrCopy(char* dest, const char* src, int dest_size)
{
	strncpy(dest, src, dest_size);
	dest[dest_size - 1] = '\0';
	return dest;
}

uint8_t* ReadFile(const char* filename, uint64_t* sizeptr)
{
	uint8_t *buf;
	uint32_t size;

	if (vb2_read_file(filename, &buf, &size) != VB2_SUCCESS) {
		fprintf(stderr, "Unable to read from file %s\n", filename);
		return NULL;
	}
	if (sizeptr)
		*sizeptr = size;
	return buf;
}

char* ReadFileFirstLine(char* dest, int size, const char* filename)
{
	char* got;
	FILE* f;

	f = fopen(filename, "rt");
	if (!f) {
		/* Crossystem uses file reading calls to also check for the file existence.
		 * Missing file means falling back to the generic non-arch dependent
		 * implementation. */
		if (errno != ENOENT)
			fprintf(stderr, "ERROR: %s: Failed to open %s: %s\n", __func__,
				filename, strerror(errno));
		return NULL;
	}

	got = fgets(dest, size, f);
	fclose(f);

	/* chomp the trailing newline if any */
	if (got)
		dest[strcspn(dest, "\r\n")] = 0;
	return got;
}

int ReadFileInt(const char* filename, unsigned* value)
{
	char buf[64];
	char* e = NULL;

	if (!ReadFileFirstLine(buf, sizeof(buf), filename))
		return -1;

	/* Convert to integer.  Allow characters after the int ("123 blah"). */
	*value = (unsigned)strtoul(buf, &e, 0);
	if (e == buf)
		return -1;  /* No characters consumed, so conversion failed */

	return 0;
}

int ReadFileBit(const char* filename, int bitmask)
{
	unsigned value;
	if (ReadFileInt(filename, &value) < 0)
		return -1;
	else return (value & bitmask ? 1 : 0);
}

vb2_error_t WriteFile(const char* filename, const void *data, uint64_t size)
{
	if (size > UINT32_MAX ||
	    vb2_write_file(filename, data, size) != VB2_SUCCESS) {
		fprintf(stderr, "Unable to write to file %s\n", filename);
		return 1;
	}
	return 0;
}

bool parse_hash(uint8_t *buf, size_t len, const char *str)
{
	for (size_t i = 0; i < len; i++) {
		while (isspace(*str))
			str++;
		if (!isxdigit(str[0]) || !isxdigit(str[1]) ||
		    sscanf(str, "%2hhx", &buf[i]) != 1)
			return false;
		str += 2;
	}

	return *str == '\0';
}

bool is_valid_property_string(const char *str)
{
	if (!str)
		return false;

	for (const char *p = str; *p; p++) {
		if (*p < 0x20 || *p >= 0x7f)
			return false;
		if (*p == '=' || *p == '\\' || *p == '\'' || *p == '"')
			return false;
	}
	return true;
}