C++ safe_strlen函数代码示例

/*
 * Replace all 'c' characters in string 'src' with the subtsring 'rep'
 * The returned string is allocated and must be freed by the caller.
 */
char* replace_char(const char* src, const char c, const char* rep)
{
	size_t i, j, k, count=0, str_len = safe_strlen(src), rep_len = safe_strlen(rep);
	char* res;

	if ((src == NULL) || (rep == NULL))
		return NULL;
	for (i=0; i<str_len; i++) {
		if (src[i] == c)
			count++;
	}
	res = (char*)malloc(str_len + count*rep_len + 1);
	if (res == NULL)
		return NULL;
	for (i=0,j=0; i<str_len; i++) {
		if (src[i] == c) {
			for(k=0; k<rep_len; k++)
				res[j++] = rep[k];
		} else {
			res[j++] = src[i];
		}
	}
	res[j] = 0;
	return res;
}

/** A safe cat of a string.
*/
void safe_cat_string(char* dest, size_t dest_len, const char* cat)
{
  size_t current_len = safe_strlen(dest);
  size_t input_len = safe_strlen(cat);

  if (dest_len < current_len + input_len + 1) {
    printf("Error catting string!\n");
    return;
  }
  memcpy(dest + current_len, cat, input_len);
  dest[current_len + input_len] = '\0';
}

static link_type
get_link_type(cmark_node *node)
{
	size_t title_len, url_len;
	cmark_node *link_text;
	char *realurl;
	int realurllen;
	bool isemail = false;

	if (node->type != CMARK_NODE_LINK) {
		return NO_LINK;
	}

	const char* url = cmark_node_get_url(node);
	cmark_chunk url_chunk = cmark_chunk_literal(url);

	url_len = safe_strlen(url);
	if (url_len == 0 || scan_scheme(&url_chunk, 0) == 0) {
		return NO_LINK;
	}

	const char* title = cmark_node_get_title(node);
	title_len = safe_strlen(title);
	// if it has a title, we can't treat it as an autolink:
	if (title_len > 0) {
		return NORMAL_LINK;
	}

	link_text = node->first_child;
	cmark_consolidate_text_nodes(link_text);
	realurl = (char*)url;
	realurllen = url_len;
	if (strncmp(realurl, "mailto:", 7) == 0) {
		realurl += 7;
		realurllen -= 7;
		isemail = true;
	}
	if (realurllen == link_text->as.literal.len &&
	    strncmp(realurl,
	            (char*)link_text->as.literal.data,
	            link_text->as.literal.len) == 0) {
		if (isemail) {
			return EMAIL_AUTOLINK;
		} else {
			return URL_AUTOLINK;
		}
	} else {
		return NORMAL_LINK;
	}
}

static int
shortest_unused_backtick_sequence(const char *code)
{
	int32_t used = 1;
	int current = 0;
	size_t i = 0;
	size_t code_len = safe_strlen(code);
	while (i <= code_len) {
		if (code[i] == '`') {
			current++;
		} else {
			if (current) {
				used |= (1 << current);
			}
			current = 0;
		}
		i++;
	}
	// return number of first bit that is 0:
	i = 0;
	while (used & 1) {
		used = used >> 1;
		i++;
	}
	return i;
}

/*
 * Open a localization file and store its file name, with special case
 * when dealing with the embedded loc file.
 */
FILE* open_loc_file(const char* filename)
{
	FILE* fd = NULL;
	wchar_t *wfilename = NULL;
	const char* tmp_ext = ".tmp";

	if (filename == NULL)
		return NULL;

	if (loc_filename != embedded_loc_filename) {
		safe_free(loc_filename);
	}
	if (safe_strcmp(tmp_ext, &filename[safe_strlen(filename)-4]) == 0) {
		loc_filename = embedded_loc_filename;
	} else {
		loc_filename = safe_strdup(filename);
	}
	wfilename = utf8_to_wchar(filename);
	if (wfilename == NULL) {
		uprintf(conversion_error, filename);
		goto out;
	}
	fd = _wfopen(wfilename, L"rb");
	if (fd == NULL) {
		uprintf("localization: could not open '%s'\n", filename);
	}

out:
	safe_free(wfilename);
	return fd;
}

/*
 * Return the next unused drive letter from the system
 */
char GetUnusedDriveLetter(void)
{
	DWORD size;
	char drive_letter = 'Z'+1, *drive, drives[26*4 + 1];	/* "D:\", "E:\", etc., plus one NUL */

	size = GetLogicalDriveStringsA(sizeof(drives), drives);
	if (size == 0) {
		uprintf("GetLogicalDriveStrings failed: %s\n", WindowsErrorString());
		goto out;
	}
	if (size > sizeof(drives)) {
		uprintf("GetLogicalDriveStrings: Buffer too small (required %d vs. %d)\n", size, sizeof(drives));
		goto out;
	}

	for (drive_letter = 'C'; drive_letter < 'Z'; drive_letter++) {
		for (drive = drives ;*drive; drive += safe_strlen(drive)+1) {
			if (!isalpha(*drive))
				continue;
			if (drive_letter == (char)toupper((int)*drive))
				break;
		}
		if (!*drive)
			break;
	}

out:
	return (drive_letter>'Z')?0:drive_letter;
}

const char *windows_error_str(DWORD retval)
{
	static char err_string[ERR_BUFFER_SIZE];

	DWORD error_code, format_error;
	DWORD size;
	ssize_t i;

	error_code = retval ? retval : GetLastError();

	safe_sprintf(err_string, ERR_BUFFER_SIZE, "[%u] ", (unsigned int)error_code);

	// Translate codes returned by SetupAPI. The ones we are dealing with are either
	// in 0x0000xxxx or 0xE000xxxx and can be distinguished from standard error codes.
	// See http://msdn.microsoft.com/en-us/library/windows/hardware/ff545011.aspx
	switch (error_code & 0xE0000000) {
	case 0:
		error_code = HRESULT_FROM_WIN32(error_code); // Still leaves ERROR_SUCCESS unmodified
		break;
	case 0xE0000000:
		error_code = 0x80000000 | (FACILITY_SETUPAPI << 16) | (error_code & 0x0000FFFF);
		break;
	default:
		break;
	}

	size = FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM, NULL, error_code,
			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), &err_string[safe_strlen(err_string)],
			ERR_BUFFER_SIZE - (DWORD)safe_strlen(err_string), NULL);
	if (size == 0) {
		format_error = GetLastError();
		if (format_error)
			safe_sprintf(err_string, ERR_BUFFER_SIZE,
					"Windows error code %u (FormatMessage error code %u)",
					(unsigned int)error_code, (unsigned int)format_error);
		else
			safe_sprintf(err_string, ERR_BUFFER_SIZE, "Unknown error code %u", (unsigned int)error_code);
	}
	else {
		// Remove CR/LF terminators
		for (i = safe_strlen(err_string) - 1; (i >= 0) && ((err_string[i] == 0x0A) || (err_string[i] == 0x0D)); i--)
			err_string[i] = 0;
	}

	return err_string;
}

/*
 * Initial update check setup
 */
BOOL SetUpdateCheck(void)
{
	BOOL enable_updates;
	DWORD commcheck = GetTickCount();
	notification_info more_info = { IDD_UPDATE_POLICY, UpdateCallback };
	char filename[MAX_PATH] = "", exename[] = APPLICATION_NAME ".exe";
	size_t fn_len, exe_len;

	// Test if we have access to the registry. If not, forget it.
	WriteRegistryKey32(REGKEY_HKCU, REGKEY_COMM_CHECK, commcheck);
	if (ReadRegistryKey32(REGKEY_HKCU, REGKEY_COMM_CHECK) != commcheck)
		return FALSE;
	reg_commcheck = TRUE;

	// If the update interval is not set, this is the first time we run so prompt the user
	if (ReadRegistryKey32(REGKEY_HKCU, REGKEY_UPDATE_INTERVAL) == 0) {

		// Add a hack for people who'd prefer the app not to prompt about update settings on first run.
		// If the executable is called "<app_name>.exe", without version, we disable the prompt
		GetModuleFileNameU(NULL, filename, sizeof(filename));
		fn_len = safe_strlen(filename);
		exe_len = safe_strlen(exename);
		if ((fn_len > exe_len) && (safe_stricmp(&filename[fn_len-exe_len], exename) == 0)) {
			dprintf("Short name used - Disabling initial update policy prompt\n");
			enable_updates = TRUE;
		} else {
			enable_updates = notification(MSG_QUESTION, &more_info, APPLICATION_NAME " update policy",
				"Do you want to allow " APPLICATION_NAME " to check for application updates online?");
		}
		if (!enable_updates) {
			WriteRegistryKey32(REGKEY_HKCU, REGKEY_UPDATE_INTERVAL, -1);
			return FALSE;
		}
		// If the user hasn't set the interval in the dialog, set to default
		if ( (ReadRegistryKey32(REGKEY_HKCU, REGKEY_UPDATE_INTERVAL) == 0) ||
			 ((ReadRegistryKey32(REGKEY_HKCU, REGKEY_UPDATE_INTERVAL) == -1) && enable_updates) )
			WriteRegistryKey32(REGKEY_HKCU, REGKEY_UPDATE_INTERVAL, 86400);
	}
	return TRUE;
}

// Apply various workarounds to Linux config files
static void fix_config(const char* psz_fullpath, const char* psz_path, const char* psz_basename, EXTRACT_PROPS* props)
{
	size_t i, nul_pos;
	char *iso_label = NULL, *usb_label = NULL, *src, *dst;

	nul_pos = safe_strlen(psz_fullpath);
	src = safe_strdup(psz_fullpath);
	if (src == NULL)
		return;
	for (i=0; i<nul_pos; i++)
		if (src[i] == '/') src[i] = '\\';

	// Workaround for config files requiring an ISO label for kernel append that may be
	// different from our USB label. Oh, and these labels must have spaces converted to \x20.
	if ((props->is_syslinux_cfg) || (props->is_grub_cfg)) {
		iso_label = replace_char(img_report.label, ' ', "\\x20");
		usb_label = replace_char(img_report.usb_label, ' ', "\\x20");
		if ((iso_label != NULL) && (usb_label != NULL)) {
			if (replace_in_token_data(src, (props->is_syslinux_cfg) ? "append" : "linuxefi", iso_label, usb_label, TRUE) != NULL)
				uprintf("  Patched %s: '%s' ⇨ '%s'\n", src, iso_label, usb_label);
		}
		safe_free(iso_label);
		safe_free(usb_label);
	}

	// Fix dual BIOS + EFI support for tails and other ISOs
	if ( (props->is_syslinux_cfg) && (safe_stricmp(psz_path, efi_dirname) == 0) &&
		 (safe_stricmp(psz_basename, syslinux_cfg[0]) == 0) &&
		 (!img_report.has_efi_syslinux) && (dst = safe_strdup(src)) ) {
		dst[nul_pos-12] = 's'; dst[nul_pos-11] = 'y'; dst[nul_pos-10] = 's';
		CopyFileA(src, dst, TRUE);
		uprintf("Duplicated %s to %s\n", src, dst);
		free(dst);
	}

	// Workaround for FreeNAS
	if (props->is_grub_cfg) {
		iso_label = malloc(MAX_PATH);
		usb_label = malloc(MAX_PATH);
		if ((iso_label != NULL) && (usb_label != NULL)) {
			safe_sprintf(iso_label, MAX_PATH, "cd9660:/dev/iso9660/%s", img_report.label);
			safe_sprintf(usb_label, MAX_PATH, "msdosfs:/dev/msdosfs/%s", img_report.usb_label);
			if (replace_in_token_data(src, "set", iso_label, usb_label, TRUE) != NULL)
				uprintf("  Patched %s: '%s' ⇨ '%s'\n", src, iso_label, usb_label);
		}
		safe_free(iso_label);
		safe_free(usb_label);
	}

	free(src);
}

static __inline char* get_sanitized_token_data_buffer(const char* token, unsigned int n, const char* buffer, size_t buffer_size)
{
	size_t i;
	char* data = get_token_data_buffer(token, n, buffer, buffer_size);
	if (data != NULL) {
		for (i=0; i<safe_strlen(data); i++) {
			if ((data[i] == '\\') && (data[i+1] == 'n')) {
				data[i] = '\r';
				data[i+1] = '\n';
			}
		}
	}
	return data;
}

// Ensure filenames do not contain invalid FAT32 or NTFS characters
static __inline BOOL sanitize_filename(char* filename)
{
	size_t i, j;
	BOOL ret = FALSE;
	char unauthorized[] = {'<', '>', ':', '|', '*', '?'};

	// Must start after the drive part (D:\...) so that we don't eliminate the first column
	for (i=2; i<safe_strlen(filename); i++) {
		for (j=0; j<sizeof(unauthorized); j++) {
			if (filename[i] == unauthorized[j]) {
				filename[i] = '_';
				ret = TRUE;
			}
		}
	}
	return ret;
}

/** build a URL, returned char* needs to be free'd */
char* pt_changes_feed_build_url(const char* server_name,
  const char* db,
  const pt_changes_feed handle)
{
  char *ret_str;
  char* end_of_string;
  size_t size_of_string = safe_strlen(server_name) + 
                          safe_strlen(db) + 
                          safe_strlen(handle->extra_opts) +
                          safe_strlen("//_changes?heartbeat=&feed=continuous") + 2048;
  ret_str = calloc(1, size_of_string);

  // Add the changes feed base URL 
  snprintf(ret_str, size_of_string, "%s/%s/_changes", server_name, db);
  if (!handle->continuous && !handle->heartbeats &&
      !safe_strlen(handle->extra_opts)) return ret_str; 
 
  // If we get here, it means that we have added options.  There is *no*
  // checking at this point!
  safe_cat_string(ret_str, size_of_string, "?");

  // Hearbeat
  if (handle->heartbeats) {
    snprintf(ret_str + safe_strlen(ret_str),size_of_string - safe_strlen(ret_str),
      "heartbeat=%i&",handle->heartbeats);
  }

  // Continuous
  if (handle->continuous) safe_cat_string(ret_str, size_of_string, "feed=continuous&");

  // Adding extra options passed by the user
  if (safe_strlen(handle->extra_opts)) safe_cat_string(ret_str, size_of_string, handle->extra_opts);
  
  // If we have an ampersand on the end, remove it
  end_of_string = &ret_str[safe_strlen(ret_str)-1];
  if (*end_of_string == '&') *end_of_string = '\0'; 
  return ret_str; 
}

/*
 * Parse an update data file and populates a rufus_update structure.
 * NB: since this is remote data, and we're running elevated, it *IS* considered
 * potentially malicious, even if it comes from a supposedly trusted server.
 * len should be the size of the buffer, including the zero terminator
 */
void parse_update(char* buf, size_t len)
{
	size_t i;
	char *data = NULL, *token;
	char allowed_rtf_chars[] = "abcdefghijklmnopqrstuvwxyz|~-_:*'";
	char allowed_std_chars[] = "\r\n ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!\"$%^&+=<>(){}[].,;#@/?";

	// strchr includes the NUL terminator in the search, so take care of backslash before NUL
	if ((buf == NULL) || (len < 2) || (len > 65536) || (buf[len-1] != 0) || (buf[len-2] == '\\'))
		return;
	// Sanitize the data - Not a silver bullet, but it helps
	len = safe_strlen(buf)+1;	// Someone may be inserting NULs
	for (i=0; i<len-1; i++) {
		// Check for valid RTF sequences as well as allowed chars if not RTF
		if (buf[i] == '\\') {
			// NB: we have a zero terminator, so we can afford a +1 without overflow
			if (strchr(allowed_rtf_chars, buf[i+1]) == NULL) {
				buf[i] = ' ';
			}
		} else if ((strchr(allowed_rtf_chars, buf[i]) == NULL) && (strchr(allowed_std_chars, buf[i]) == NULL)) {
			buf[i] = ' ';
		}
	}

	for (i=0; i<3; i++)
		update.version[i] = 0;
	update.platform_min[0] = 5;
	update.platform_min[1] = 2;	// XP or later
	safe_free(update.download_url);
	safe_free(update.release_notes);
	if ((data = get_sanitized_token_data_buffer("version", 1, buf, len)) != NULL) {
		for (i=0; (i<3) && ((token = strtok((i==0)?data:NULL, ".")) != NULL); i++) {
			update.version[i] = (uint16_t)atoi(token);
		}
		safe_free(data);
	}
	if ((data = get_sanitized_token_data_buffer("platform_min", 1, buf, len)) != NULL) {
		for (i=0; (i<2) && ((token = strtok((i==0)?data:NULL, ".")) != NULL); i++) {
			update.platform_min[i] = (uint32_t)atoi(token);
		}
		safe_free(data);
	}
	update.download_url = get_sanitized_token_data_buffer("download_url", 1, buf, len);
	update.release_notes = get_sanitized_token_data_buffer("release_notes", 1, buf, len);
}

static int longest_backtick_sequence(const char *code) {
  int longest = 0;
  int current = 0;
  size_t i = 0;
  size_t code_len = safe_strlen(code);
  while (i <= code_len) {
    if (code[i] == '`') {
      current++;
    } else {
      if (current > longest) {
        longest = current;
      }
      current = 0;
    }
    i++;
  }
  return longest;
}

/*
 * Send individual lines of the syslog section pointed by buffer back to the main application
 * xbuffer's payload MUST start at byte 1 to accomodate the SYSLOG_MESSAGE prefix
 */
DWORD process_syslog(char* buffer, DWORD size)
{
	DWORD i, write_size, junk, start = 0;
	char* xbuffer;
	char* ins_string = "<ins>";
	char conversion_error[] = " ERROR: Unable to convert log entry to UTF-8";

	if (buffer == NULL) return 0;

	// CR/LF breakdown
	for (i=0; i<size; i++) {
		if ((buffer[i] == 0x0D) || (buffer[i] == 0x0A)) {
			write_size = i-start + 1;
			do {
				buffer[i++] = 0;
			} while ( ((buffer[i] == 0x0D) || (buffer[i] == 0x0A)) && (i <= size) );

			// The setupapi.dev.log uses a dubious method to mark its current position
			// If there's any "<ins>" line in any log file, it's game over then
			if (safe_strcmp(ins_string, buffer + start) == 0) {
				return start;
			}

			// The logs are using the system locale. Convert to UTF8 (with extra leading byte)
			xbuffer = xlocale_to_utf8(&buffer[start]);
			if (xbuffer == NULL) {
				xbuffer = conversion_error;
			}

			// This is where we use the extra start byte
			xbuffer[0] = IC_SYSLOG_MESSAGE;
			WriteFile(pipe_handle, xbuffer, (DWORD)safe_strlen(&xbuffer[1])+2, &junk, NULL);
			if (xbuffer != conversion_error) {
				free(xbuffer);
			}
			start = i;
		}
	}
	// start does not necessarily equate size, if there are truncated lines at the end
	return start;
}