diff options
Diffstat (limited to 'util')
| -rw-r--r-- | util/nvmutil/nvmutil.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/util/nvmutil/nvmutil.c b/util/nvmutil/nvmutil.c index 585f73bb..aa795b26 100644 --- a/util/nvmutil/nvmutil.c +++ b/util/nvmutil/nvmutil.c @@ -1329,6 +1329,18 @@ gbe_x_offset(size_t p, const char *f_op, const char *d_type, return off; } +/* + * Read or write the exact contents of a file, + * along with a buffer, (if applicable) offset, + * and number of bytes to be read. It unified + * the functionality of read(), pread(), write() + * and pwrite(), with retry-on-EINTR and also + * prevents infinite loop on zero-reads. + * + * The pread() and pwrite() functionality are + * provided by yet another portable function, + * prw() - see notes below. + */ static void rw_file_exact(int fd, uint8_t *mem, size_t len, off_t off, int rw_type, const char *path, @@ -1382,6 +1394,15 @@ rw_file_exact(int fd, uint8_t *mem, size_t len, } } +/* + * This implements a portable analog of pwrite() + * and pread() - note that this version is not + * thread-safe (race conditions are possible on + * shared file descriptors). + * + * This limitation is acceptable, since nvmutil is + * single-threaded. Portability is the main goal. + */ static ssize_t prw(int fd, void *mem, size_t nrw, off_t off, int rw_type) |