/**
* Load the contents of a text file. There are two separate implementations,
* depending up on whether mmap(3) is available.
*
* If not available, malloc the file length plus one byte. Read it in
* and NUL terminate.
*
* If available, first check to see if the text file size is a multiple of a
* page size. If it is, map the file size plus an extra page from either
* anonymous memory or from /dev/zero. Then map the file text on top of the
* first pages of the anonymous/zero pages. Otherwise, just map the file
* because there will be NUL bytes provided at the end.
*
* @param mapinfo a structure holding everything we need to know
* about the mapping.
*
* @param pzFile name of the file, for error reporting.
*/
static void
load_text_file(tmap_info_t * mapinfo, char const * pzFile)
{
#if ! defined(HAVE_MMAP)
mapinfo->txt_data = AGALOC(mapinfo->txt_size+1, "file text");
if (mapinfo->txt_data == NULL) {
mapinfo->txt_errno = ENOMEM;
return;
}
{
size_t sz = mapinfo->txt_size;
char* pz = mapinfo->txt_data;
while (sz > 0) {
ssize_t rdct = read(mapinfo->txt_fd, pz, sz);
if (rdct <= 0) {
mapinfo->txt_errno = errno;
fserr_warn("libopts", "read", pzFile);
free(mapinfo->txt_data);
return;
}
pz += rdct;
sz -= rdct;
}
*pz = NUL;
}
mapinfo->txt_errno = 0;
#else /* HAVE mmap */
size_t const pgsz = (size_t)GETPAGESIZE();
void * map_addr = NULL;
(void)pzFile;
mapinfo->txt_full_size = (mapinfo->txt_size + pgsz) & ~(pgsz - 1);
if (mapinfo->txt_full_size == (mapinfo->txt_size + pgsz)) {
/*
* The text is a multiple of a page boundary. We must map an
* extra page so the text ends with a NUL.
*/
#if defined(MAP_ANONYMOUS)
map_addr = mmap(NULL, mapinfo->txt_full_size, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, AO_INVALID_FD, 0);
#else
mapinfo->txt_zero_fd = open("/dev/zero", O_RDONLY);
if (mapinfo->txt_zero_fd == AO_INVALID_FD) {
mapinfo->txt_errno = errno;
return;
}
map_addr = mmap(NULL, mapinfo->txt_full_size, PROT_READ|PROT_WRITE,
MAP_PRIVATE, mapinfo->txt_zero_fd, 0);
#endif
if (map_addr == MAP_FAILED_PTR) {
mapinfo->txt_errno = errno;
return;
}
mapinfo->txt_flags |= MAP_FIXED;
}
mapinfo->txt_data =
mmap(map_addr, mapinfo->txt_size, mapinfo->txt_prot,
mapinfo->txt_flags, mapinfo->txt_fd, 0);
if (mapinfo->txt_data == MAP_FAILED_PTR)
mapinfo->txt_errno = errno;
#endif /* HAVE_MMAP */
}
LOCAL noreturn void
fserr_exit(char const * prog, char const * op, char const * fname)
{
fserr_warn(prog, op, fname);
option_exits(EXIT_FAILURE);
}
