From 1f5062f656b4919ff1d3126c413c40e53fdd1ab2 Mon Sep 17 00:00:00 2001 From: Julian Andres Klode Date: Mon, 28 Dec 2015 22:30:44 +0100 Subject: [PATCH] BufferedFileFdPrivate: Make InternalFlush() save against errors Previously, if flush errored inside the loop, data could have already been written to the wrapped descriptor without having been removed from the buffer. Also try to work around EINTR here. A better solution might be to have the individual privates detect an interrupt and return 0 in such a case, instead of relying on errno being untouched in between the syscall and the return from InternalWrite. --- apt-pkg/contrib/fileutl.cc | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc index 0c5d76290..7f3ed673a 100644 --- a/apt-pkg/contrib/fileutl.cc +++ b/apt-pkg/contrib/fileutl.cc @@ -1218,16 +1218,16 @@ public: } virtual bool InternalFlush() override { - size_t written = 0; - char *data = writebuffer.get(); - auto size = writebuffer.size(); - - while (written < size) { - auto written_this_time = wrapped->InternalWrite(data + written, size - written); - if (written_this_time < 0) + while (writebuffer.empty() == false) { + auto written = wrapped->InternalWrite(writebuffer.get(), + writebuffer.size()); + // Ignore interrupted syscalls + if (written < 0 && errno == EINTR) + continue; + if (written < 0) return false; - written += written_this_time; + writebuffer.bufferstart += written; } writebuffer.reset(); -- 2.45.2