2:39 a.m.
Jonh, I split the 1st patch the other way to avoid changing same
lines of code in subsequent patches.
Diff to v1[1]
- split 1st patch into 3
- change wordings of commit messages/error messages
- add minor changes to code as suggested by John
[1] https://www.redhat.com/archives/libvir-list/2019-February/msg00920.html
Nikolay Shirokovskiy (4):
tools: console: cleanup console on errors in main thread
tools: console: add missing locks in callbacks
tools: console: check if console was shutdown in callbacks
tools: console: pass stream/fd errors to user
tools/virsh-console.c | 224 ++++++++++++++++++++++++++++++++++++++------------
1 file changed, 171 insertions(+), 53 deletions(-)
--
1.8.3.1
2:39 a.m.
New subject: [libvirt] [PATCH v2 1/4] tools: console: cleanup console on errors in main thread
We only check now for virObjectWait failures in virshRunConsole but
we'd better check and for other failures too. Anyway if failure
happened we need to shutdown console to stop delivering events
from event loop thread or we are in trouble as console is freed
on virshRunConsole exit.
We need to turn console into virObject object because stream/fd callbacks
can be called from a event loop thread after shutdown/freeing console
in main thread. It is convinient to turn into virLockableObject as
we have mutex in console object.
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy(a)virtuozzo.com>
---
tools/virsh-console.c | 122 +++++++++++++++++++++++++++++++++++---------------
1 file changed, 87 insertions(+), 35 deletions(-)
diff --git a/tools/virsh-console.c b/tools/virsh-console.c
index 045a636..9289221 100644
--- a/tools/virsh-console.c
+++ b/tools/virsh-console.c
@@ -60,9 +60,10 @@ struct virConsoleBuffer {
typedef struct virConsole virConsole;
typedef virConsole *virConsolePtr;
struct virConsole {
+ virObjectLockable parent;
+
virStreamPtr st;
bool quit;
- virMutex lock;
virCond cond;
int stdinWatch;
@@ -74,6 +75,19 @@ struct virConsole {
char escapeChar;
};
+static virClassPtr virConsoleClass;
+static void virConsoleDispose(void *obj);
+
+static int
+virConsoleOnceInit(void)
+{
+ if (!VIR_CLASS_NEW(virConsole, virClassForObjectLockable()))
+ return -1;
+
+ return 0;
+}
+
+VIR_ONCE_GLOBAL_INIT(virConsole);
static void
virConsoleHandleSignal(int sig ATTRIBUTE_UNUSED)
@@ -98,22 +112,22 @@ virConsoleShutdown(virConsolePtr con)
virEventRemoveHandle(con->stdoutWatch);
con->stdinWatch = -1;
con->stdoutWatch = -1;
- con->quit = true;
- virCondSignal(&con->cond);
+ if (!con->quit) {
+ con->quit = true;
+ virCondSignal(&con->cond);
+ }
}
static void
-virConsoleFree(virConsolePtr con)
+virConsoleDispose(void *obj)
{
- if (!con)
- return;
+ virConsolePtr con = obj;
if (con->st)
virStreamFree(con->st);
- virMutexDestroy(&con->lock);
+
virCondDestroy(&con->cond);
- VIR_FREE(con);
}
@@ -288,6 +302,35 @@ virConsoleEventOnStdout(int watch ATTRIBUTE_UNUSED,
}
+static virConsolePtr
+virConsoleNew(void)
+{
+ virConsolePtr con;
+
+ if (virConsoleInitialize() < 0)
+ return NULL;
+
+ if (!(con = virObjectNew(virConsoleClass)))
+ return NULL;
+
+ if (virCondInit(&con->cond) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("cannot initialize console condition"));
+
+ goto error;
+ }
+
+ con->stdinWatch = -1;
+ con->stdoutWatch = -1;
+
+ return con;
+
+ error:
+ virObjectUnref(con);
+ return NULL;
+}
+
+
static char
virshGetEscapeChar(const char *s)
{
@@ -324,6 +367,11 @@ virshRunConsole(vshControl *ctl,
if (vshTTYMakeRaw(ctl, true) < 0)
goto resettty;
+ if (!(con = virConsoleNew()))
+ goto resettty;
+
+ virObjectLock(con);
+
/* Trap all common signals so that we can safely restore the original
* terminal settings on STDIN before the process exits - people don't like
* being left with a messed up terminal ! */
@@ -333,9 +381,6 @@ virshRunConsole(vshControl *ctl,
sigaction(SIGHUP, &sighandler, &old_sighup);
sigaction(SIGPIPE, &sighandler, &old_sigpipe);
- if (VIR_ALLOC(con) < 0)
- goto cleanup;
-
con->escapeChar = virshGetEscapeChar(priv->escapeChar);
con->st = virStreamNew(virDomainGetConnect(dom),
VIR_STREAM_NONBLOCK);
@@ -345,42 +390,49 @@ virshRunConsole(vshControl *ctl,
if (virDomainOpenConsole(dom, dev_name, con->st, flags) < 0)
goto cleanup;
- if (virCondInit(&con->cond) < 0 || virMutexInit(&con->lock) < 0)
+ virObjectRef(con);
+ if ((con->stdinWatch = virEventAddHandle(STDIN_FILENO,
+ VIR_EVENT_HANDLE_READABLE,
+ virConsoleEventOnStdin,
+ con,
+ virObjectFreeCallback)) < 0) {
+ virObjectUnref(con);
+ goto cleanup;
+ }
+
+ virObjectRef(con);
+ if ((con->stdoutWatch = virEventAddHandle(STDOUT_FILENO,
+ 0,
+ virConsoleEventOnStdout,
+ con,
+ virObjectFreeCallback)) < 0) {
+ virObjectUnref(con);
goto cleanup;
+ }
- virMutexLock(&con->lock);
-
- con->stdinWatch = virEventAddHandle(STDIN_FILENO,
- VIR_EVENT_HANDLE_READABLE,
- virConsoleEventOnStdin,
- con,
- NULL);
- con->stdoutWatch = virEventAddHandle(STDOUT_FILENO,
- 0,
- virConsoleEventOnStdout,
- con,
- NULL);
-
- virStreamEventAddCallback(con->st,
- VIR_STREAM_EVENT_READABLE,
- virConsoleEventOnStream,
- con,
- NULL);
+ virObjectRef(con);
+ if (virStreamEventAddCallback(con->st,
+ VIR_STREAM_EVENT_READABLE,
+ virConsoleEventOnStream,
+ con,
+ virObjectFreeCallback) < 0) {
+ virObjectUnref(con);
+ goto cleanup;
+ }
while (!con->quit) {
- if (virCondWait(&con->cond, &con->lock) < 0) {
- virMutexUnlock(&con->lock);
+ if (virCondWait(&con->cond, &con->parent.lock) < 0) {
VIR_ERROR(_("unable to wait on console condition"));
goto cleanup;
}
}
- virMutexUnlock(&con->lock);
-
ret = 0;
cleanup:
- virConsoleFree(con);
+ virConsoleShutdown(con);
+ virObjectUnlock(con);
+ virObjectUnref(con);
/* Restore original signal handlers */
sigaction(SIGQUIT, &old_sigquit, NULL);
--
1.8.3.1
5:56 a.m.
New subject: [libvirt] [PATCH v2 1/4] tools: console: cleanup console on errors in main thread
On Wed, Mar 13, 2019 at 10:39:46AM +0300, Nikolay Shirokovskiy wrote:
We only check now for virObjectWait failures in virshRunConsole but
we'd better check and for other failures too. Anyway if failure
happened we need to shutdown console to stop delivering events
from event loop thread or we are in trouble as console is freed
on virshRunConsole exit.
We need to turn console into virObject object because stream/fd callbacks
can be called from a event loop thread after shutdown/freeing console
in main thread. It is convinient to turn into virLockableObject as
we have mutex in console object.
Could you do this in two separate patches - one which refactors into
a virObject, and the second which does the actual error handling
fixes.
The changes look ok, but distinguishing the actual fix from the
refactoring is hard.
Regards,
Daniel
--
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2:39 a.m.
New subject: [libvirt] [PATCH v2 2/4] tools: console: add missing locks in callbacks
Stream/fd callbacks accessing console object are called from the
event loop thread and the console object is also accessed from
the main thread so we are better add locking to handlers.
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy(a)virtuozzo.com>
---
tools/virsh-console.c | 35 +++++++++++++++++++++++++----------
1 file changed, 25 insertions(+), 10 deletions(-)
diff --git a/tools/virsh-console.c b/tools/virsh-console.c
index 9289221..3dae707 100644
--- a/tools/virsh-console.c
+++ b/tools/virsh-console.c
@@ -137,6 +137,8 @@ virConsoleEventOnStream(virStreamPtr st,
{
virConsolePtr con = opaque;
+ virObjectLock(con);
+
if (events & VIR_STREAM_EVENT_READABLE) {
size_t avail = con->streamToTerminal.length -
con->streamToTerminal.offset;
@@ -146,7 +148,7 @@ virConsoleEventOnStream(virStreamPtr st,
if (VIR_REALLOC_N(con->streamToTerminal.data,
con->streamToTerminal.length + 1024) < 0) {
virConsoleShutdown(con);
- return;
+ goto cleanup;
}
con->streamToTerminal.length += 1024;
avail += 1024;
@@ -157,10 +159,10 @@ virConsoleEventOnStream(virStreamPtr st,
con->streamToTerminal.offset,
avail);
if (got == -2)
- return; /* blocking */
+ goto cleanup; /* blocking */
if (got <= 0) {
virConsoleShutdown(con);
- return;
+ goto cleanup;
}
con->streamToTerminal.offset += got;
if (con->streamToTerminal.offset)
@@ -176,10 +178,10 @@ virConsoleEventOnStream(virStreamPtr st,
con->terminalToStream.data,
con->terminalToStream.offset);
if (done == -2)
- return; /* blocking */
+ goto cleanup; /* blocking */
if (done < 0) {
virConsoleShutdown(con);
- return;
+ goto cleanup;
}
memmove(con->terminalToStream.data,
con->terminalToStream.data + done,
@@ -201,6 +203,9 @@ virConsoleEventOnStream(virStreamPtr st,
events & VIR_STREAM_EVENT_HANGUP) {
virConsoleShutdown(con);
}
+
+ cleanup:
+ virObjectUnlock(con);
}
@@ -212,6 +217,8 @@ virConsoleEventOnStdin(int watch ATTRIBUTE_UNUSED,
{
virConsolePtr con = opaque;
+ virObjectLock(con);
+
if (events & VIR_EVENT_HANDLE_READABLE) {
size_t avail = con->terminalToStream.length -
con->terminalToStream.offset;
@@ -221,7 +228,7 @@ virConsoleEventOnStdin(int watch ATTRIBUTE_UNUSED,
if (VIR_REALLOC_N(con->terminalToStream.data,
con->terminalToStream.length + 1024) < 0) {
virConsoleShutdown(con);
- return;
+ goto cleanup;
}
con->terminalToStream.length += 1024;
avail += 1024;
@@ -234,15 +241,15 @@ virConsoleEventOnStdin(int watch ATTRIBUTE_UNUSED,
if (got < 0) {
if (errno != EAGAIN)
virConsoleShutdown(con);
- return;
+ goto cleanup;
}
if (got == 0) {
virConsoleShutdown(con);
- return;
+ goto cleanup;
}
if (con->terminalToStream.data[con->terminalToStream.offset] ==
con->escapeChar) {
virConsoleShutdown(con);
- return;
+ goto cleanup;
}
con->terminalToStream.offset += got;
@@ -256,6 +263,9 @@ virConsoleEventOnStdin(int watch ATTRIBUTE_UNUSED,
events & VIR_EVENT_HANDLE_HANGUP) {
virConsoleShutdown(con);
}
+
+ cleanup:
+ virObjectUnlock(con);
}
@@ -267,6 +277,8 @@ virConsoleEventOnStdout(int watch ATTRIBUTE_UNUSED,
{
virConsolePtr con = opaque;
+ virObjectLock(con);
+
if (events & VIR_EVENT_HANDLE_WRITABLE &&
con->streamToTerminal.offset) {
ssize_t done;
@@ -277,7 +289,7 @@ virConsoleEventOnStdout(int watch ATTRIBUTE_UNUSED,
if (done < 0) {
if (errno != EAGAIN)
virConsoleShutdown(con);
- return;
+ goto cleanup;
}
memmove(con->streamToTerminal.data,
con->streamToTerminal.data + done,
@@ -299,6 +311,9 @@ virConsoleEventOnStdout(int watch ATTRIBUTE_UNUSED,
events & VIR_EVENT_HANDLE_HANGUP) {
virConsoleShutdown(con);
}
+
+ cleanup:
+ virObjectUnlock(con);
}
--
1.8.3.1
2:39 a.m.
New subject: [libvirt] [PATCH v2 3/4] tools: console: check if console was shutdown in callbacks
On error in main thread virConsoleShutdown is called which
deletes fd watches/stream callback and yet callbacks can
be called after. Thus we can incorrectly allocate
terminalToStream.data memory and get memory leak for example.
Let's check if console was shutdown in the very beginning of
callbacks.
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy(a)virtuozzo.com>
---
tools/virsh-console.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/tools/virsh-console.c b/tools/virsh-console.c
index 3dae707..d109734 100644
--- a/tools/virsh-console.c
+++ b/tools/virsh-console.c
@@ -139,6 +139,10 @@ virConsoleEventOnStream(virStreamPtr st,
virObjectLock(con);
+ /* we got late event after console was shutdown */
+ if (!con->st)
+ goto cleanup;
+
if (events & VIR_STREAM_EVENT_READABLE) {
size_t avail = con->streamToTerminal.length -
con->streamToTerminal.offset;
@@ -219,6 +223,10 @@ virConsoleEventOnStdin(int watch ATTRIBUTE_UNUSED,
virObjectLock(con);
+ /* we got late event after console was shutdown */
+ if (!con->st)
+ goto cleanup;
+
if (events & VIR_EVENT_HANDLE_READABLE) {
size_t avail = con->terminalToStream.length -
con->terminalToStream.offset;
@@ -279,6 +287,10 @@ virConsoleEventOnStdout(int watch ATTRIBUTE_UNUSED,
virObjectLock(con);
+ /* we got late event after console was shutdown */
+ if (!con->st)
+ goto cleanup;
+
if (events & VIR_EVENT_HANDLE_WRITABLE &&
con->streamToTerminal.offset) {
ssize_t done;
--
1.8.3.1
2:39 a.m.
New subject: [libvirt] [PATCH v2 4/4] tools: console: pass stream/fd errors to user
If the console was disconnected due to a connection problem or a problem on the
server side it is convinient to provide the cause to the user. If the error
come from the API then the error is saved in a virsh global variable. However,
since success is returned from virshRunConsole after we reach the waiting stage,
then the error is never reported. Let's track the error in the event loop.
Next after failure we do a cleanup and this cleanup can overwrite
root cause. Thus let's save root cause immediately and then set it to
virsh error after all cleanup is done.
Since we'll be sending the error to the consumer, each failure path from
the event handlers needs to be augmented to provide what error generated
the failure.
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy(a)virtuozzo.com>
---
tools/virsh-console.c | 55 +++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 47 insertions(+), 8 deletions(-)
diff --git a/tools/virsh-console.c b/tools/virsh-console.c
index d109734..236933a 100644
--- a/tools/virsh-console.c
+++ b/tools/virsh-console.c
@@ -73,6 +73,7 @@ struct virConsole {
struct virConsoleBuffer terminalToStream;
char escapeChar;
+ virError error;
};
static virClassPtr virConsoleClass;
@@ -98,6 +99,11 @@ virConsoleHandleSignal(int sig ATTRIBUTE_UNUSED)
static void
virConsoleShutdown(virConsolePtr con)
{
+ virErrorPtr err = virGetLastError();
+
+ if (con->error.code == VIR_ERR_OK && err && err->code !=
VIR_ERR_OK)
+ virCopyLastError(&con->error);
+
if (con->st) {
virStreamEventRemoveCallback(con->st);
virStreamAbort(con->st);
@@ -128,6 +134,7 @@ virConsoleDispose(void *obj)
virStreamFree(con->st);
virCondDestroy(&con->cond);
+ virResetError(&con->error);
}
@@ -165,6 +172,10 @@ virConsoleEventOnStream(virStreamPtr st,
if (got == -2)
goto cleanup; /* blocking */
if (got <= 0) {
+ if (got == 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("console stream EOF"));
+ }
virConsoleShutdown(con);
goto cleanup;
}
@@ -247,11 +258,14 @@ virConsoleEventOnStdin(int watch ATTRIBUTE_UNUSED,
con->terminalToStream.offset,
avail);
if (got < 0) {
- if (errno != EAGAIN)
+ if (errno != EAGAIN) {
+ virReportSystemError(errno, "%s", _("cannot read from
stdin"));
virConsoleShutdown(con);
+ }
goto cleanup;
}
if (got == 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("EOF on
stdin"));
virConsoleShutdown(con);
goto cleanup;
}
@@ -267,9 +281,16 @@ virConsoleEventOnStdin(int watch ATTRIBUTE_UNUSED,
VIR_STREAM_EVENT_WRITABLE);
}
- if (events & VIR_EVENT_HANDLE_ERROR ||
- events & VIR_EVENT_HANDLE_HANGUP) {
+ if (events & VIR_EVENT_HANDLE_ERROR) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("IO error on
stdin"));
virConsoleShutdown(con);
+ goto cleanup;
+ }
+
+ if (events & VIR_EVENT_HANDLE_HANGUP) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("EOF on
stdin"));
+ virConsoleShutdown(con);
+ goto cleanup;
}
cleanup:
@@ -299,8 +320,10 @@ virConsoleEventOnStdout(int watch ATTRIBUTE_UNUSED,
con->streamToTerminal.data,
con->streamToTerminal.offset);
if (done < 0) {
- if (errno != EAGAIN)
+ if (errno != EAGAIN) {
+ virReportSystemError(errno, "%s", _("cannot write to
stdout"));
virConsoleShutdown(con);
+ }
goto cleanup;
}
memmove(con->streamToTerminal.data,
@@ -319,9 +342,16 @@ virConsoleEventOnStdout(int watch ATTRIBUTE_UNUSED,
if (!con->streamToTerminal.offset)
virEventUpdateHandle(con->stdoutWatch, 0);
- if (events & VIR_EVENT_HANDLE_ERROR ||
- events & VIR_EVENT_HANDLE_HANGUP) {
+ if (events & VIR_EVENT_HANDLE_ERROR) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("IO error
stdout"));
virConsoleShutdown(con);
+ goto cleanup;
+ }
+
+ if (events & VIR_EVENT_HANDLE_HANGUP) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("EOF on
stdout"));
+ virConsoleShutdown(con);
+ goto cleanup;
}
cleanup:
@@ -449,15 +479,24 @@ virshRunConsole(vshControl *ctl,
while (!con->quit) {
if (virCondWait(&con->cond, &con->parent.lock) < 0) {
- VIR_ERROR(_("unable to wait on console condition"));
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("unable to wait on console condition"));
goto cleanup;
}
}
- ret = 0;
+ if (con->error.code == VIR_ERR_OK)
+ ret = 0;
cleanup:
virConsoleShutdown(con);
+
+ if (ret < 0) {
+ vshResetLibvirtError();
+ virSetError(&con->error);
+ vshSaveLibvirtHelperError();
+ }
+
virObjectUnlock(con);
virObjectUnref(con);
--
1.8.3.1
2117
days inactive
2119
days old
5 comments
2 participants
participants (2)
-
Daniel P. Berrangé -
Nikolay Shirokovskiy