void
vsf_secbuf_alloc(char** p_ptr, unsigned int size)
{
unsigned int page_offset;
unsigned int round_up;
char* p_mmap;
char* p_no_access_page;
unsigned int page_size = vsf_sysutil_getpagesize();
/* Free any previous buffer */
vsf_secbuf_free(p_ptr);
/* Round up to next page size */
page_offset = size % page_size;
if (page_offset)
{
unsigned int num_pages = size / page_size;
num_pages++;
round_up = num_pages * page_size;
}
else
{
/* Allocation is on a page-size boundary */
round_up = size;
}
/* Add on another two pages to make inaccessible */
round_up += page_size * 2;
p_mmap = vsf_sysutil_map_anon_pages(round_up);
/* Map the first and last page inaccessible */
p_no_access_page = p_mmap + round_up - page_size;
vsf_sysutil_memprotect(p_no_access_page, page_size, kVSFSysUtilMapProtNone);
/* Before we make the "before" page inaccessible, store the size in it.
* A little hack so that we don't need to explicitly be passed the size
* when freeing an existing secure buffer
*/
*((unsigned int*)p_mmap) = round_up;
p_no_access_page = p_mmap;
/* fix issue with MIPS SCACHE on MT7621 (and no sense to hide value of mapped block size) */
vsf_sysutil_memprotect(p_no_access_page, page_size, kVSFSysUtilMapProtReadOnly);
p_mmap += page_size;
if (page_offset)
{
p_mmap += (page_size - page_offset);
}
*p_ptr = p_mmap;
}
int
str_fileread(struct mystr* p_str, const char* p_filename, unsigned int maxsize)
{
int fd;
int retval = 0;
filesize_t size;
char* p_sec_buf = 0;
struct vsf_sysutil_statbuf* p_stat = 0;
/* In case we fail, make sure we return an empty string */
str_empty(p_str);
fd = vsf_sysutil_open_file(p_filename, kVSFSysUtilOpenReadOnly);
if (vsf_sysutil_retval_is_error(fd))
{
return fd;
}
vsf_sysutil_fstat(fd, &p_stat);
if (vsf_sysutil_statbuf_is_regfile(p_stat))
{
size = vsf_sysutil_statbuf_get_size(p_stat);
if (size > maxsize)
{
size = maxsize;
}
vsf_secbuf_alloc(&p_sec_buf, (unsigned int) size);
retval = vsf_sysutil_read_loop(fd, p_sec_buf, (unsigned int) size);
if (vsf_sysutil_retval_is_error(retval))
{
goto free_out;
}
else if ((unsigned int) retval != size)
{
die("read size mismatch");
}
str_alloc_memchunk(p_str, p_sec_buf, size);
}
free_out:
vsf_sysutil_free(p_stat);
vsf_secbuf_free(&p_sec_buf);
vsf_sysutil_close(fd);
return retval;
}
