/*
* util_file_pread -- reads from a file with an offset
*/
ssize_t
util_file_pread(const char *path, void *buffer, size_t size,
off_t offset)
{
if (!util_file_is_device_dax(path)) {
int fd = util_file_open(path, NULL, 0, O_RDONLY);
if (fd < 0)
return -1;
ssize_t read_len = pread(fd, buffer, size, offset);
int olderrno = errno;
(void) close(fd);
errno = olderrno;
return read_len;
}
ssize_t file_size = util_file_get_size(path);
if (file_size < 0)
return -1;
size_t max_size = (size_t)(file_size - offset);
if (size > max_size) {
LOG(1, "Requested size of read goes beyond the mapped memory");
size = max_size;
}
void *addr = util_file_map_whole(path);
if (addr == NULL)
return -1;
memcpy(buffer, ADDR_SUM(addr, offset), size);
util_unmap(addr, (size_t)file_size);
return (ssize_t)size;
}
/*
* util_file_pread -- reads from a file with an offset
*/
ssize_t
util_file_pread(const char *path, void *buffer, size_t size,
os_off_t offset)
{
LOG(3, "path \"%s\" buffer %p size %zu offset %ju",
path, buffer, size, offset);
enum file_type type = util_file_get_type(path);
if (type < 0)
return -1;
if (type == TYPE_NORMAL) {
int fd = util_file_open(path, NULL, 0, O_RDONLY);
if (fd < 0) {
LOG(2, "failed to open file \"%s\"", path);
return -1;
}
ssize_t read_len = pread(fd, buffer, size, offset);
int olderrno = errno;
(void) os_close(fd);
errno = olderrno;
return read_len;
}
ssize_t file_size = util_file_get_size(path);
if (file_size < 0) {
LOG(2, "cannot determine file length \"%s\"", path);
return -1;
}
size_t max_size = (size_t)(file_size - offset);
if (size > max_size) {
LOG(2, "requested size of read goes beyond the file length, "
"%zu > %zu", size, max_size);
LOG(4, "adjusting size to %zu", max_size);
size = max_size;
}
void *addr = util_file_map_whole(path);
if (addr == NULL) {
LOG(2, "failed to map entire file \"%s\"", path);
return -1;
}
memcpy(buffer, ADDR_SUM(addr, offset), size);
util_unmap(addr, (size_t)file_size);
return (ssize_t)size;
}
