From 71dd405460b7b1251af9a71aa30c74b7d40da1c3 Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Wed, 20 Mar 2024 09:47:26 +0100 Subject: [PATCH] util: fix confusion between offset in the iovec array and in the entry In write_remainder() 'skip' is the offset to start the operation from in the iovec array. In iov_skip_bytes(), 'skip' is also the offset in the iovec array but 'offset' is the first unskipped byte in the iovec entry. As write_remainder() uses 'skip' for both, 'skip' is reset to the first unskipped byte in the iovec entry rather to staying the first unskipped byte in the iovec array. Fix the problem by introducing a new variable not to overwrite 'skip' on each loop. Fixes: 8bdb0883b441 ("util: Add write_remainder() helper") Signed-off-by: Laurent Vivier Reviewed-by: David Gibson Signed-off-by: Stefano Brivio --- util.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/util.c b/util.c index 3b2393d..849fa7f 100644 --- a/util.c +++ b/util.c @@ -533,13 +533,14 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags, int write_remainder(int fd, const struct iovec *iov, int iovcnt, size_t skip) { int i; + size_t offset; - while ((i = iov_skip_bytes(iov, iovcnt, skip, &skip)) < iovcnt) { + while ((i = iov_skip_bytes(iov, iovcnt, skip, &offset)) < iovcnt) { ssize_t rc; - if (skip) { - rc = write(fd, (char *)iov[i].iov_base + skip, - iov[i].iov_len - skip); + if (offset) { + rc = write(fd, (char *)iov[i].iov_base + offset, + iov[i].iov_len - offset); } else { rc = writev(fd, &iov[i], iovcnt - i); }