From 74d26d446e9cf31dd80e893b4c47dc438334df1b Mon Sep 17 00:00:00 2001 From: Leah Rowe Date: Sat, 14 Mar 2026 21:21:31 +0000 Subject: util/nvmutil: move looping logic to rw_file_exact rw_file_once was doing what rw_file_exact should be doing _once does what it says: once we were passing an offset (rc) to it that it was not meaningfully using. this makes the code now more robust, especially if we later swap out or break _once - then we don't get weird behaviour (if there is a regression). Signed-off-by: Leah Rowe --- util/nvmutil/nvmutil.c | 35 ++++++++++++++++++++--------------- 1 file changed, 20 insertions(+), 15 deletions(-) (limited to 'util/nvmutil/nvmutil.c') diff --git a/util/nvmutil/nvmutil.c b/util/nvmutil/nvmutil.c index 37d51515..ba4ee1e3 100644 --- a/util/nvmutil/nvmutil.c +++ b/util/nvmutil/nvmutil.c @@ -411,7 +411,7 @@ static ssize_t rw_file_once(int fd, u8 *mem, size_t len, static ssize_t prw(int fd, void *mem, size_t nrw, off_t off, int rw_type, int loop_eagain, int loop_eintr); static int check_file(int fd, struct stat *st); -static int rw_over_nrw(ssize_t r, size_t nrw); +static ssize_t rw_over_nrw(ssize_t r, size_t nrw); static off_t lseek_loop(int fd, off_t off, int whence, int loop_eagain, int loop_eintr); static int try_err(int loop_err, int errval); @@ -1874,32 +1874,37 @@ rw_file_exact(int fd, u8 *mem, size_t nrw, int loop_eintr, size_t max_retries) { ssize_t rv = 0; - size_t rc = 0; + ssize_t rc = 0; + size_t retries_on_zero = 0; - for (rc = 0, rv = 0; rc < nrw; ) { + while (1) { - rc += (size_t)rv; + rc += rv; + if ((size_t)rc >= nrw) + break; if ((rv = rw_file_once(fd, mem + rc, nrw - rc, off + rc, rw_type, loop_eagain, loop_eintr, max_retries)) < 0) return -1; - /* rw_file_once never returns - zero, but it's still logically - incorrect not to handle it here */ - + /* Prevent theoretical overflow */ + if ((size_t)rv > (nrw - rc)) + goto err_rw_file_exact; + if (rv == 0) { - errno = EIO; - return -1; + if (retries_on_zero++ < max_retries) + continue; + goto err_rw_file_exact; } - /* Prevent theoretical overflow */ - if ((size_t)rv > nrw - rc) - goto err_rw_file_exact; + retries_on_zero = 0; } - return rc; + if ((size_t)rc != nrw) + goto err_rw_file_exact; + + return rw_over_nrw(rc, nrw); err_rw_file_exact: errno = EIO; @@ -2113,7 +2118,7 @@ err_is_file: * POSIX can say whatever it wants. * specification != implementation */ -static int +static ssize_t rw_over_nrw(ssize_t r, size_t nrw) { if (r == -1) -- cgit v1.2.1