* Re: [PATCH] kvm tools: Setup bridged network by a script
@ 2011-04-16 9:55 Ingo Molnar
2011-04-18 0:12 ` [PATCH] kvm tools: Add robust error handling for fork/waitpid() Amos Kong
0 siblings, 1 reply; 3+ messages in thread
From: Ingo Molnar @ 2011-04-16 9:55 UTC (permalink / raw)
To: Pekka Enberg; +Cc: KVM devel mailing list, Amos Kong
Hi, i noticed this small detail:
+ if (strcmp(params->script, "none")) {
+ pid = fork();
+ if (pid == 0) {
+ execl(params->script, params->script, net_device.tap_name, NULL);
+ _exit(1);
+ } else {
+ waitpid(pid, &status, 0);
+ if (WIFEXITED(status) && WEXITSTATUS(status) != 0) {
+ warning("Fail to setup tap by %s", params->script);
+ goto fail;
+ }
+ }
this path does not seem to have robust error handling: both fork() and
waitpid() can (and sometimes do) fail. If waitpid() fails then 'status' might
be ununitialized as well, IIRC.
Thanks,
Ingo
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH] kvm tools: Add robust error handling for fork/waitpid() 2011-04-16 9:55 [PATCH] kvm tools: Setup bridged network by a script Ingo Molnar @ 2011-04-18 0:12 ` Amos Kong 2011-04-18 6:34 ` Ingo Molnar 0 siblings, 1 reply; 3+ messages in thread From: Amos Kong @ 2011-04-18 0:12 UTC (permalink / raw) To: kvm; +Cc: penberg, asias.hejun, mingo > Hi, i noticed this small detail: > > + if (strcmp(params->script, "none")) { > + pid = fork(); > + if (pid == 0) { > + execl(params->script, params->script, net_device.tap_name, NULL); > + _exit(1); > + } else { > + waitpid(pid, &status, 0); > + if (WIFEXITED(status) && WEXITSTATUS(status) != 0) { > + warning("Fail to setup tap by %s", params->script); > + goto fail; > + } > + } > > this path does not seem to have robust error handling: both fork() and > waitpid() can (and sometimes do) fail. If waitpid() fails then 'status' might > be ununitialized as well, IIRC. > > Thanks, > > Ingo Signed-off-by: Amos Kong <kongjianjun@gmail.com> --- tools/kvm/virtio-net.c | 11 ++++++----- 1 files changed, 6 insertions(+), 5 deletions(-) diff --git a/tools/kvm/virtio-net.c b/tools/kvm/virtio-net.c index f8d7276..430769a 100644 --- a/tools/kvm/virtio-net.c +++ b/tools/kvm/virtio-net.c @@ -311,13 +311,14 @@ static bool virtio_net__tap_init(const struct virtio_net_parameters *params) if (pid == 0) { execl(params->script, params->script, net_device.tap_name, NULL); _exit(1); - } else { - waitpid(pid, &status, 0); - if (WIFEXITED(status) && WEXITSTATUS(status) != 0) { - warning("Fail to setup tap by %s", params->script); - goto fail; + } else if (pid > 0) { + while(waitpid(pid, &status, 0) != pid) { } } + if (pid < 0 || (WIFEXITED(status) && WEXITSTATUS(status) != 0)) { + warning("Fail to setup tap by %s", params->script); + goto fail; + } } else { memset(&ifr, 0, sizeof(ifr)); ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] kvm tools: Add robust error handling for fork/waitpid() 2011-04-18 0:12 ` [PATCH] kvm tools: Add robust error handling for fork/waitpid() Amos Kong @ 2011-04-18 6:34 ` Ingo Molnar 0 siblings, 0 replies; 3+ messages in thread From: Ingo Molnar @ 2011-04-18 6:34 UTC (permalink / raw) To: Amos Kong; +Cc: kvm, penberg, asias.hejun * Amos Kong <kongjianjun@gmail.com> wrote: > + } else if (pid > 0) { > + while(waitpid(pid, &status, 0) != pid) { > } > } Doesn't that look like an infinite loop when waitpid() returns an error? Thanks, Ingo ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-04-18 6:34 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2011-04-16 9:55 [PATCH] kvm tools: Setup bridged network by a script Ingo Molnar 2011-04-18 0:12 ` [PATCH] kvm tools: Add robust error handling for fork/waitpid() Amos Kong 2011-04-18 6:34 ` Ingo Molnar
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