Based on a warning from coverity. The safe* functions guarantee complete transactions on success, but don't guarantee freedom from failure. * src/util/util.h (saferead, safewrite, safezero): Add ATTRIBUTE_RETURN_CHECK. * src/remote/remote_driver.c (remoteIO, remoteIOEventLoop): Ignore some failures. (remoteIOReadBuffer): Adjust error messages on read failure. * daemon/event.c (virEventHandleWakeup): Ignore read failure. --- Coverity claimed that safewrite was checked 37 out of 46 times, but only flagged one instance of a CHECKED_RETURN report, against remote_driver.c. I didn't spot the 9 unchecked calls that coverity's numbers would imply. Meanwhile, adding the attribute ensures that we don't forget this in the future. Please double-check if my use of ignore_value on some of the previously unchecked calls makes sense, or if we need a more invasive patch to deal with real failure. daemon/event.c | 5 +++-- src/remote/remote_driver.c | 13 +++++++++---- src/util/util.h | 9 ++++++--- 3 files changed, 18 insertions(+), 9 deletions(-) diff --git a/daemon/event.c b/daemon/event.c index 2218a3e..36e9dd3 100644 --- a/daemon/event.c +++ b/daemon/event.c @@ -1,8 +1,8 @@ /* * event.c: event loop for monitoring file handles * + * Copyright (C) 2007, 2010 Red Hat, Inc. * Copyright (C) 2007 Daniel P. Berrange - * Copyright (C) 2007 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -35,6 +35,7 @@ #include "event.h" #include "memory.h" #include "util.h" +#include "ignore-value.h" #define EVENT_DEBUG(fmt, ...) DEBUG(fmt, __VA_ARGS__) @@ -630,7 +631,7 @@ static void virEventHandleWakeup(int watch ATTRIBUTE_UNUSED, { char c; virEventLock(); - saferead(fd, &c, sizeof(c)); + ignore_value (saferead(fd, &c, sizeof(c))); virEventUnlock(); } diff --git a/src/remote/remote_driver.c b/src/remote/remote_driver.c index def4617..47d8c56 100644 --- a/src/remote/remote_driver.c +++ b/src/remote/remote_driver.c @@ -7809,7 +7809,9 @@ remoteIOReadBuffer(virConnectPtr conn, char errout[1024] = "\0"; if (priv->errfd != -1) { - saferead(priv->errfd, errout, sizeof(errout)); + if (saferead(priv->errfd, errout, sizeof(errout)) < 0) { + strncpy (errout, _("unknown reason"), sizeof errout); + } } virReportSystemError(errno, @@ -7818,7 +7820,9 @@ remoteIOReadBuffer(virConnectPtr conn, } else { char errout[1024] = "\0"; if (priv->errfd != -1) { - saferead(priv->errfd, errout, sizeof(errout)); + if (saferead(priv->errfd, errout, sizeof(errout)) < 0) { + strncpy (errout, _("unknown reason"), sizeof errout); + } } errorf (in_open ? NULL : conn, @@ -8431,7 +8435,8 @@ remoteIOEventLoop(virConnectPtr conn, if (fds[1].revents) { DEBUG0("Woken up from poll by other thread"); - saferead(priv->wakeupReadFD, &ignore, sizeof(ignore)); + ignore_value (saferead(priv->wakeupReadFD, &ignore, + sizeof(ignore))); } if (ret < 0) { @@ -8575,7 +8580,7 @@ remoteIO(virConnectPtr conn, priv->waitDispatch = thiscall; /* Force other thread to wakup from poll */ - safewrite(priv->wakeupSendFD, &ignore, sizeof(ignore)); + ignore_value (safewrite(priv->wakeupSendFD, &ignore, sizeof(ignore))); DEBUG("Going to sleep %d %p %p", thiscall->proc_nr, priv->waitDispatch, thiscall); /* Go to sleep while other thread is working... */ diff --git a/src/util/util.h b/src/util/util.h index cc05abe..34b77fa 100644 --- a/src/util/util.h +++ b/src/util/util.h @@ -2,6 +2,7 @@ /* * utils.h: common, generic utility functions * + * Copyright (C) 2010 Red Hat, Inc. * Copyright (C) 2006, 2007 Binary Karma * Copyright (C) 2006 Shuveb Hussain * @@ -31,9 +32,11 @@ #include <sys/select.h> #include <sys/types.h> -int saferead(int fd, void *buf, size_t count); -ssize_t safewrite(int fd, const void *buf, size_t count); -int safezero(int fd, int flags, off_t offset, off_t len); +int saferead(int fd, void *buf, size_t count) ATTRIBUTE_RETURN_CHECK; +ssize_t safewrite(int fd, const void *buf, size_t count) + ATTRIBUTE_RETURN_CHECK; +int safezero(int fd, int flags, off_t offset, off_t len) + ATTRIBUTE_RETURN_CHECK; enum { VIR_EXEC_NONE = 0, -- 1.6.6.1