This patch adds a set of flags to be used with the virDomainOpenConsole API call to specify if the user wishes to interrupt an existing console session or just to try open a new one. VIR_DOMAIN_CONSOLE_SAFE - specifies that the console connection should be opened only if the hypervisor supports mutually exclusive access to console devices VIR_DOMAIN_CONSOLE_FORCE - specifies that the caller wishes to interrupt existing session and force a creation of a new one. --- No change. include/libvirt/libvirt.h.in | 12 ++++++++++++ src/libvirt.c | 18 ++++++++++++++++-- 2 files changed, 28 insertions(+), 2 deletions(-) diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in index 798ab07..bafd4ea 100644 --- a/include/libvirt/libvirt.h.in +++ b/include/libvirt/libvirt.h.in @@ -3747,7 +3747,19 @@ int virNWFilterGetUUIDString (virNWFilterPtr nwfilter, char *buf); char * virNWFilterGetXMLDesc (virNWFilterPtr nwfilter, unsigned int flags); +/** + * virDomainConsoleFlags + * + * Since 0.9.10 + */ +typedef enum { + VIR_DOMAIN_CONSOLE_FORCE = (1 << 0), /* abort a (possibly) active console + connection to force a new + connection */ + VIR_DOMAIN_CONSOLE_SAFE = (1 << 1), /* check if the console driver supports + safe console operations */ +} virDomainConsoleFlags; int virDomainOpenConsole(virDomainPtr dom, const char *devname, diff --git a/src/libvirt.c b/src/libvirt.c index 6294196..9f01e6d 100644 --- a/src/libvirt.c +++ b/src/libvirt.c @@ -17717,7 +17717,7 @@ virDomainSnapshotFree(virDomainSnapshotPtr snapshot) * @dom: a domain object * @dev_name: the console, serial or parallel port device alias, or NULL * @st: a stream to associate with the console - * @flags: extra flags; not used yet, so callers should always pass 0 + * @flags: bitwise-OR of virDomainConsoleFlags * * This opens the backend associated with a console, serial or * parallel port device on a guest, if the backend is supported. @@ -17726,7 +17726,21 @@ virDomainSnapshotFree(virDomainSnapshotPtr snapshot) * in @st stream, which should have been opened in non-blocking * mode for bi-directional I/O. * - * returns 0 if the console was opened, -1 on error + * By default, when @flags is 0, the open will fail if libvirt + * detects that the console is already in use by another client; + * passing VIR_DOMAIN_CONSOLE_FORCE will cause libvirt to forcefully + * remove the other client prior to opening this console. + * + * If flag VIR_DOMAIN_CONSOLE_SAFE the console is opened only in the + * case where the hypervisor driver supports safe (mutually exclusive) + * console handling. + * + * Older servers did not support either flag, and also did not forbid + * simultaneous clients on a console, with potentially confusing results. + * When passing @flags of 0 in order to support a wider range of server + * versions, it is up to the client to ensure mutual exclusion. + * + * Returns 0 if the console was opened, -1 on error */ int virDomainOpenConsole(virDomainPtr dom, const char *dev_name, -- 1.7.3.4

This patch causes the fdstream driver to call the stream event callback if virStreamAbort() is called on a stream using this driver. A remote handler for a stream can only detect changes via stream events, so this event callback is necessary in order to enable a daemon to abort a stream in such a way that the client will see the change. * src/fdstream.c: - modify close function to call stream event callback --- Diff to v4: - reworded commit message - fixed year - added caching of pointers to callback before dropping the lock - moved lines belonging to this patch here Note to comment in v4 review: fdst->abortCallbackCalled needs to be cleared only if the callback handler is set. This is not needed when we just update the events for the callback. src/fdstream.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++----- 1 files changed, 57 insertions(+), 6 deletions(-) diff --git a/src/fdstream.c b/src/fdstream.c index 841f979..39a8753 100644 --- a/src/fdstream.c +++ b/src/fdstream.c @@ -1,7 +1,7 @@ /* - * fdstream.h: generic streams impl for file descriptors + * fdstream.c: generic streams impl for file descriptors * - * Copyright (C) 2009-2011 Red Hat, Inc. + * Copyright (C) 2009-2012 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 @@ -55,6 +55,7 @@ struct virFDStreamData { unsigned long long length; int watch; + int events; /* events the stream callback is subscribed for */ bool cbRemoved; bool dispatching; bool closed; @@ -62,6 +63,10 @@ struct virFDStreamData { void *opaque; virFreeCallback ff; + /* don't call the abort callback more than once */ + bool abortCallbackCalled; + bool abortCallbackDispatching; + virMutex lock; }; @@ -92,6 +97,7 @@ static int virFDStreamRemoveCallback(virStreamPtr stream) fdst->watch = 0; fdst->ff = NULL; fdst->cb = NULL; + fdst->events = 0; fdst->opaque = NULL; ret = 0; @@ -120,6 +126,7 @@ static int virFDStreamUpdateCallback(virStreamPtr stream, int events) } virEventUpdateHandle(fdst->watch, events); + fdst->events = events; ret = 0; @@ -214,6 +221,8 @@ virFDStreamAddCallback(virStreamPtr st, fdst->cb = cb; fdst->opaque = opaque; fdst->ff = ff; + fdst->events = events; + fdst->abortCallbackCalled = false; virStreamRef(st); ret = 0; @@ -225,18 +234,48 @@ cleanup: static int -virFDStreamClose(virStreamPtr st) +virFDStreamCloseInt(virStreamPtr st, bool streamAbort) { - struct virFDStreamData *fdst = st->privateData; + struct virFDStreamData *fdst; + virStreamEventCallback cb; + void *opaque; int ret; VIR_DEBUG("st=%p", st); - if (!fdst) + if (!st || !(fdst = st->privateData) || fdst->abortCallbackDispatching) return 0; virMutexLock(&fdst->lock); + /* aborting the stream, ensure the callback is called if it's + * registered for stream error event */ + if (streamAbort && + fdst->cb && + (fdst->events & (VIR_STREAM_EVENT_READABLE | + VIR_STREAM_EVENT_WRITABLE))) { + /* don't enter this function accidentally from the callback again */ + if (fdst->abortCallbackCalled) { + virMutexUnlock(&fdst->lock); + return 0; + } + + fdst->abortCallbackCalled = true; + fdst->abortCallbackDispatching = true; + + /* cache the pointers */ + cb = fdst->cb; + opaque = fdst->opaque; + virMutexUnlock(&fdst->lock); + + /* call failure callback, poll reports nothing on closed fd */ + (cb)(st, VIR_STREAM_EVENT_ERROR, opaque); + + virMutexLock(&fdst->lock); + fdst->abortCallbackDispatching = false; + } + + /* mutex locked */ ret = VIR_CLOSE(fdst->fd); if (fdst->cmd) { char buf[1024]; @@ -286,6 +325,18 @@ virFDStreamClose(virStreamPtr st) return ret; } +static int +virFDStreamClose(virStreamPtr st) +{ + return virFDStreamCloseInt(st, false); +} + +static int +virFDStreamAbort(virStreamPtr st) +{ + return virFDStreamCloseInt(st, true); +} + static int virFDStreamWrite(virStreamPtr st, const char *bytes, size_t nbytes) { struct virFDStreamData *fdst = st->privateData; @@ -392,7 +443,7 @@ static virStreamDriver virFDStreamDrv = { .streamSend = virFDStreamWrite, .streamRecv = virFDStreamRead, .streamFinish = virFDStreamClose, - .streamAbort = virFDStreamClose, + .streamAbort = virFDStreamAbort, .streamAddCallback = virFDStreamAddCallback, .streamUpdateCallback = virFDStreamUpdateCallback, .streamRemoveCallback = virFDStreamRemoveCallback -- 1.7.3.4

This patch adds a set of functions used in creating console streams for domains using PTYs and ensures mutually exclusive access to the PTYs. If mutualy exclusive access is not used, two clients may open the same console, which results in corruption on both clients as both of them race to read data from the PTY. Two approaches are used to ensure this: 1) Internal data structure holding open PTYs. This is used internally and enables the user to forcibly terminate another console connection eg. when somebody leaves the console open on another host. 2) UUCP style lock files: This uses UUCP lock files according to the FHS ( http://www.pathname.com/fhs/pub/fhs-2.3.html#VARLOCKLOCKFILES ) to check if other programs (like minicom) are not using the pty device of the console. This feature is disabled by default and may be enabled using configure parameter --with-console-lock-files=/path/to/lock/file/directory or --with-console-lock-files=auto (which tries to infer the location from OS used (currently only linux). On usual linux systems, normal users may not write to the /var/lock directory containing the locks. This poses problems while in session mode. If the current user has no access to the lockfile directory, check for presence of the file is still done, but no lock file is created. This does NOT result in an error. --- Diff to v4: - fixed typos (traditionally) - fixed configure.ac to work with automaticaly used values - tweaked configure output line to line up with others without moving them - using STRSKIP to skip the start of the string instead of possibly skipping in the middle of a string - fixed whitespace problems - changed data type for pids to pid_t and tweaked printing formatters - On failure to initialise mutex in virConsoleAlloc don't skip to virConsoleFree - added comment to clarify why it's needed to unregister the callback handler - Added OOM error reporting on some error paths. Note to v4 review: I changed the default value for the path of the lock files to "auto" so it will get built with "/var/lock" on linux machines, so no change to the spec file is needed. configure.ac | 25 +++ po/POTFILES.in | 1 + src/Makefile.am | 6 +- src/conf/virconsole.c | 408 ++++++++++++++++++++++++++++++++++++++++++++++ src/conf/virconsole.h | 36 ++++ src/libvirt_private.syms | 6 + 6 files changed, 481 insertions(+), 1 deletions(-) create mode 100644 src/conf/virconsole.c create mode 100644 src/conf/virconsole.h diff --git a/configure.ac b/configure.ac index 732f4fe..a5f9105 100644 --- a/configure.ac +++ b/configure.ac @@ -336,6 +336,12 @@ AC_ARG_WITH([remote], AC_HELP_STRING([--with-remote], [add remote driver support @<:@default=yes@:>@]),[],[with_remote=yes]) AC_ARG_WITH([libvirtd], AC_HELP_STRING([--with-libvirtd], [add libvirtd support @<:@default=yes@:>@]),[],[with_libvirtd=yes]) +AC_ARG_WITH([console-lock-files], + AC_HELP_STRING([--with-console-lock-files], + [location for UUCP style lock files for console PTYs + (use auto for default paths on some platforms) + @<:@default=auto@:>@]), + [],[with_console_lock_files=auto]) dnl dnl in case someone want to build static binaries @@ -1206,6 +1212,24 @@ AM_CONDITIONAL([HAVE_AUDIT], [test "$with_audit" = "yes"]) AC_SUBST([AUDIT_CFLAGS]) AC_SUBST([AUDIT_LIBS]) +dnl UUCP style file locks for PTY consoles +if test "$with_console_lock_files" != "no"; then + if test "$with_console_lock_files" = "yes"; then + AC_MSG_ERROR([console lock files requested, but no path given]) + elif test "$with_console_lock_files" = "auto"; then + dnl Default locations for platforms + if test "$with_linux" = "yes"; then + with_console_lock_files=/var/lock + fi + fi + if test "$with_console_lock_files" = "auto"; then + AC_MSG_ERROR([You must specify path for the lock files on this platform]) + fi + AC_DEFINE_UNQUOTED([VIR_PTY_LOCK_FILE_PATH], "$with_console_lock_files", + [path to directory containing UUCP pty lock files]) +fi +AM_CONDITIONAL([VIR_PTY_LOCK_FILE_PATH], [test "$with_console_lock_files" != "no"]) + dnl SELinux AC_ARG_WITH([selinux], @@ -2742,6 +2766,7 @@ AC_MSG_NOTICE([ Python: $with_python]) AC_MSG_NOTICE([ DTrace: $with_dtrace]) AC_MSG_NOTICE([ XML Catalog: $XML_CATALOG_FILE]) AC_MSG_NOTICE([ Init script: $with_init_script]) +AC_MSG_NOTICE([Console locks: $with_console_lock_files]) AC_MSG_NOTICE([]) AC_MSG_NOTICE([Privileges]) AC_MSG_NOTICE([]) diff --git a/po/POTFILES.in b/po/POTFILES.in index 0eff13b..16a3f9e 100644 --- a/po/POTFILES.in +++ b/po/POTFILES.in @@ -17,6 +17,7 @@ src/conf/nwfilter_params.c src/conf/secret_conf.c src/conf/storage_conf.c src/conf/storage_encryption_conf.c +src/conf/virconsole.c src/cpu/cpu.c src/cpu/cpu_generic.c src/cpu/cpu_map.c diff --git a/src/Makefile.am b/src/Makefile.am index d5f52a0..18086fb 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -184,6 +184,9 @@ ENCRYPTION_CONF_SOURCES = \ CPU_CONF_SOURCES = \ conf/cpu_conf.c conf/cpu_conf.h +# Safe console handling helper APIs +CONSOLE_CONF_SOURCES = \ + conf/virconsole.c conf/virconsole.h CONF_SOURCES = \ $(NETDEV_CONF_SOURCES) \ @@ -196,7 +199,8 @@ CONF_SOURCES = \ $(ENCRYPTION_CONF_SOURCES) \ $(INTERFACE_CONF_SOURCES) \ $(SECRET_CONF_SOURCES) \ - $(CPU_CONF_SOURCES) + $(CPU_CONF_SOURCES) \ + $(CONSOLE_CONF_SOURCES) # The remote RPC driver, covering domains, storage, networks, etc REMOTE_DRIVER_GENERATED = \ diff --git a/src/conf/virconsole.c b/src/conf/virconsole.c new file mode 100644 index 0000000..aeb7d3d --- /dev/null +++ b/src/conf/virconsole.c @@ -0,0 +1,408 @@ +/** + * virconsole.c: api to guarantee mutually exclusive + * access to domain's consoles + * + * Copyright (C) 2011-2012 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 + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * Author: Peter Krempa <pkrempa(a)redhat.com&gt; + */ + +#include <config.h> + +#include <fcntl.h> +#include <unistd.h> +#include <sys/types.h> + +#include "virconsole.h" +#include "virhash.h" +#include "fdstream.h" +#include "internal.h" +#include "threads.h" +#include "memory.h" +#include "virpidfile.h" +#include "logging.h" +#include "virterror_internal.h" +#include "virfile.h" + +#define VIR_FROM_THIS VIR_FROM_NONE +#define virConsoleError(code, ...) \ + virReportErrorHelper(VIR_FROM_THIS, code, __FILE__, \ + __FUNCTION__, __LINE__, __VA_ARGS__) + +/* structure holding information about consoles + * open in a given domain */ +struct _virConsoles { + virMutex lock; + virHashTablePtr hash; +}; + +typedef struct _virConsoleStreamInfo virConsoleStreamInfo; +typedef virConsoleStreamInfo *virConsoleStreamInfoPtr; +struct _virConsoleStreamInfo { + virConsolesPtr cons; + const char *pty; +}; + +#ifdef VIR_PTY_LOCK_FILE_PATH +/** + * Create a full filename with path to the lock file based on + * name/path of corresponding pty + * + * @pty path of the console device + * + * Returns a modified name that the caller has to free, or NULL + * on error. + */ +static char *virConsoleLockFilePath(const char *pty) +{ + char *path = NULL; + char *sanitizedPath = NULL; + char *ptyCopy; + char *filename; + char *p; + + if (!(ptyCopy = strdup(pty))) { + virReportOOMError(); + goto cleanup; + } + + /* skip the leading "/dev/" */ + filename = STRSKIP(ptyCopy, "/dev"); + if (!filename) + filename = ptyCopy; + + /* substitute path forward slashes for underscores */ + p = filename; + while (*p) { + if (*p == '/') + *p = '_'; + ++p; + } + + if (virAsprintf(&path, "%s/LCK..%s", VIR_PTY_LOCK_FILE_PATH, filename) < 0) + goto cleanup; + + sanitizedPath = virFileSanitizePath(path); + +cleanup: + VIR_FREE(path); + VIR_FREE(ptyCopy); + + return sanitizedPath; +} + +/** + * Verify and create a lock file for a console pty + * + * @pty Path of the console device + * + * Returns 0 on success, -1 on error + */ +static int virConsoleLockFileCreate(const char *pty) +{ + char *path = NULL; + int ret = -1; + int lockfd = -1; + char *pidStr = NULL; + pid_t pid; + + /* build lock file path */ + if (!(path = virConsoleLockFilePath(pty))) + goto cleanup; + + /* check if a log file and process holding the lock still exists */ + if (virPidFileReadPathIfAlive(path, &pid, NULL) == 0 && pid >= 0) { + /* the process exists, the lockfile is valid */ + virConsoleError(VIR_ERR_OPERATION_FAILED, + _("Requested console pty '%s' is locked by " + "lock file '%s' held by process %lld"), + pty, path, pid); + goto cleanup; + } else { + /* clean up the stale/corrupted/nonexistent lockfile */ + unlink(path); + } + /* lockfile doesn't (shouldn't) exist */ + + /* ensure correct format according to filesystem hierarchy standard */ + /* http://www.pathname.com/fhs/pub/fhs-2.3.html#VARLOCKLOCKFILES */ + if (virAsprintf(&pidStr, "%10lld\n", (long long) getpid()) < 0) + goto cleanup; + + /* create the lock file */ + if ((lockfd = open(path, O_WRONLY | O_CREAT | O_EXCL, 00644)) < 0) { + /* If we run in session mode, we might have no access to the lock + * file directory. We have to check for an permission denied error + * and see if we can reach it. This should cause an error only if + * we run in daemon mode and thus privileged. + */ + if (errno == EACCES && geteuid() != 0) { + VIR_DEBUG("Skipping lock file creation for pty '%s in path '%s'.", + pty, path); + ret = 0; + goto cleanup; + } + virReportSystemError(errno, + _("Couldn't create lock file for " + "pty '%s' in path '%s'"), + pty, path); + goto cleanup; + } + + /* write the pid to the file */ + if (safewrite(lockfd, pidStr, strlen(pidStr)) < 0) { + virReportSystemError(errno, + _("Couldn't write to lock file for " + "pty '%s' in path '%s'"), + pty, path); + VIR_FORCE_CLOSE(lockfd); + unlink(path); + goto cleanup; + } + + /* we hold the lock */ + ret = 0; + +cleanup: + VIR_FORCE_CLOSE(lockfd); + VIR_FREE(path); + VIR_FREE(pidStr); + + return ret; +} + +/** + * Remove a lock file for a pty + * + * @pty Path of the pty device + */ +static void virConsoleLockFileRemove(const char *pty) +{ + char *path = virConsoleLockFilePath(pty); + if (path) + unlink(path); + VIR_FREE(path); +} +#else /* #ifdef VIR_PTY_LOCK_FILE_PATH */ +/* file locking for console devices is disabled */ +static int virConsoleLockFileCreate(const char *pty ATTRIBUTE_UNUSED) +{ + return 0; +} + +static void virConsoleLockFileRemove(const char *pty ATTRIBUTE_UNUSED) +{ + return; +} +#endif /* #ifdef VIR_PTY_LOCK_FILE_PATH */ + +/** + * Frees an entry from the hash containing domain's active consoles + * + * @data Opaque data, struct holding information about the console + * @name Path of the pty. + */ +static void virConsoleHashEntryFree(void *data, + const void *name) +{ + const char *pty = name; + virStreamPtr st = data; + + /* free stream reference */ + virStreamFree(st); + + /* delete lock file */ + virConsoleLockFileRemove(pty); +} + +/** + * Frees opaque data provided for the stream closing callback + * + * @opaque Data to be freed. + */ +static void virConsoleFDStreamCloseCbFree(void *opaque) +{ + virConsoleStreamInfoPtr priv = opaque; + + VIR_FREE(priv->pty); + VIR_FREE(priv); +} + +/** + * Callback being called if a FDstream is closed. Frees console entries + * from data structures and removes lockfiles. + * + * @st Pointer to stream being closed. + * @opaque Domain's console information structure. + */ +static void virConsoleFDStreamCloseCb(virStreamPtr st ATTRIBUTE_UNUSED, + void *opaque) +{ + virConsoleStreamInfoPtr priv = opaque; + virMutexLock(&priv->cons->lock); + + /* remove entry from hash */ + virHashRemoveEntry(priv->cons->hash, priv->pty); + + virMutexUnlock(&priv->cons->lock); +} + +/** + * Allocate structures for storing information about active console streams + * in domain's private data section. + * + * Returns pointer to the allocated structure or NULL on error + */ +virConsolesPtr virConsoleAlloc(void) +{ + virConsolesPtr cons; + if (VIR_ALLOC(cons) < 0) + return NULL; + + if (virMutexInit(&cons->lock) < 0) { + VIR_FREE(cons); + return NULL; + } + + /* there will hardly be any consoles most of the time, the hash + * does not have to be huge */ + if (!(cons->hash = virHashCreate(3, virConsoleHashEntryFree))) + goto error; + + return cons; +error: + virConsoleFree(cons); + return NULL; +} + +/** + * Free structures for handling open console streams. + * + * @cons Pointer to the private structure. + */ +void virConsoleFree(virConsolesPtr cons) +{ + if (!cons || !cons->hash) + return; + + virMutexLock(&cons->lock); + virHashFree(cons->hash); + virMutexUnlock(&cons->lock); + virMutexDestroy(&cons->lock); + + VIR_FREE(cons); +} + +/** + * Open a console stream for a domain ensuring that other streams are + * not using the console, nor any lockfiles exist. This ensures that + * the console stream does not get corrupted due to a race on reading + * same FD by two processes. + * + * @cons Pointer to private structure holding data about console streams. + * @pty Path to the pseudo tty to be opened. + * @st Stream the client wishes to use for the console connection. + * @force On true, close active console streams for the selected console pty + * before opening this connection. + * + * Returns 0 on success and st is connected to the selected pty and + * corresponding lock file is created (if configured). Returns -1 on + * error and 1 if the console stream is open and busy. + */ +int virConsoleOpen(virConsolesPtr cons, + const char *pty, + virStreamPtr st, + bool force) +{ + virConsoleStreamInfoPtr cbdata = NULL; + virStreamPtr savedStream; + int ret; + + virMutexLock(&cons->lock); + + if ((savedStream = virHashLookup(cons->hash, pty))) { + if (!force) { + /* entry found, console is busy */ + virMutexUnlock(&cons->lock); + return 1; + } else { + /* terminate existing connection */ + /* The internal close callback handler needs to lock cons->lock to + * remove the aborted stream from the hash. This would cause a + * deadlock as we would try to enter the lock twice from the very + * same thread. We need to unregister the callback and abort the + * stream manualy before we create a new console connection. + */ + virFDStreamSetInternalCloseCb(savedStream, NULL, NULL, NULL); + virStreamAbort(savedStream); + virHashRemoveEntry(cons->hash, pty); + /* continue adding a new stream connection */ + } + } + + /* create the lock file */ + if ((ret = virConsoleLockFileCreate(pty)) < 0) { + virMutexUnlock(&cons->lock); + return ret; + } + + /* obtain a reference to the stream */ + if (virStreamRef(st) < 0) { + virMutexUnlock(&cons->lock); + return -1; + } + + if (VIR_ALLOC(cbdata) < 0) { + virReportOOMError(); + goto error; + } + + if (virHashAddEntry(cons->hash, pty, st) < 0) + goto error; + + cbdata->cons = cons; + if (!(cbdata->pty = strdup(pty))) { + virReportOOMError(); + goto error; + } + + /* open the console pty */ + if (virFDStreamOpenFile(st, pty, 0, 0, O_RDWR) < 0) + goto error; + + savedStream = st; + st = NULL; + + /* add cleanup callback */ + virFDStreamSetInternalCloseCb(savedStream, + virConsoleFDStreamCloseCb, + cbdata, + virConsoleFDStreamCloseCbFree); + cbdata = NULL; + + virMutexUnlock(&cons->lock); + return 0; + +error: + virStreamFree(st); + virHashRemoveEntry(cons->hash, pty); + if (cbdata) + VIR_FREE(cbdata->pty); + VIR_FREE(cbdata); + virMutexUnlock(&cons->lock); + return -1; +} diff --git a/src/conf/virconsole.h b/src/conf/virconsole.h new file mode 100644 index 0000000..7cdf578 --- /dev/null +++ b/src/conf/virconsole.h @@ -0,0 +1,36 @@ +/** + * virconsole.h: api to guarantee mutually exclusive + * access to domain's consoles + * + * Copyright (C) 2011-2012 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 + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * Author: Peter Krempa <pkrempa(a)redhat.com&gt; + */ +#ifndef __VIR_CONSOLE_H__ +# define __VIR_CONSOLE_H__ + +# include "internal.h" + +typedef struct _virConsoles virConsoles; +typedef virConsoles *virConsolesPtr; + +virConsolesPtr virConsoleAlloc(void); +void virConsoleFree(virConsolesPtr cons); + +int virConsoleOpen(virConsolesPtr cons, const char *pty, + virStreamPtr st, bool force); +#endif /*__VIR_DOMAIN_CONSOLE_LOCK_H__*/ diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 9e3573f..b9ce287 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1156,6 +1156,12 @@ virAuditOpen; virAuditSend; +# virconsole.h +virConsoleAlloc; +virConsoleFree; +virConsoleOpen; + + # virfile.h virFileClose; virFileDirectFdFlag; -- 1.7.3.4

This patch fixes console corruption, that happens if two concurrent sessions are opened for a single console on a domain. Result of this corruption was that each of the console streams recieved just a part of the data written to the pipe so every console rendered unusable. New helper function for safe console handling is used to establish the console stream connection. This function ensures that no other libvirt client is using the console (with the ability to disconnect consoles of libvirt clients) and that no UUCP style lockfile is placed on the PTY device. * src/qemu/qemu_domain.h - add data structure to domain's private data dealing with console connections * src/qemu/qemu_domain.c: - allocate/free domain's console data structure * src/qemu/qemu_driver.c - use the new helper function for console handling --- No changes. src/qemu/qemu_domain.c | 5 +++++ src/qemu/qemu_domain.h | 3 +++ src/qemu/qemu_driver.c | 21 ++++++++++++++++----- 3 files changed, 24 insertions(+), 5 deletions(-) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 01e5580..2fed91e 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -192,6 +192,9 @@ static void *qemuDomainObjPrivateAlloc(void) if (qemuDomainObjInitJob(priv) < 0) goto error; + if (!(priv->cons = virConsoleAlloc())) + goto error; + priv->migMaxBandwidth = QEMU_DOMAIN_DEFAULT_MIG_BANDWIDTH_MAX; return priv; @@ -214,6 +217,8 @@ static void qemuDomainObjPrivateFree(void *data) VIR_FREE(priv->lockState); VIR_FREE(priv->origname); + virConsoleFree(priv->cons); + /* This should never be non-NULL if we get here, but just in case... */ if (priv->mon) { VIR_ERROR(_("Unexpected QEMU monitor still active during domain deletion")); diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h index 222d80e..1333d8c 100644 --- a/src/qemu/qemu_domain.h +++ b/src/qemu/qemu_domain.h @@ -30,6 +30,7 @@ # include "qemu_agent.h" # include "qemu_conf.h" # include "bitmap.h" +# include "virconsole.h" # define QEMU_EXPECTED_VIRT_TYPES \ ((1 << VIR_DOMAIN_VIRT_QEMU) | \ @@ -127,6 +128,8 @@ struct _qemuDomainObjPrivate { unsigned long migMaxBandwidth; char *origname; + + virConsolesPtr cons; }; struct qemuDomainWatchdogEvent diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 717bdf1..1d869fb 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -11243,8 +11243,10 @@ qemuDomainOpenConsole(virDomainPtr dom, int ret = -1; int i; virDomainChrDefPtr chr = NULL; + qemuDomainObjPrivatePtr priv; - virCheckFlags(0, -1); + virCheckFlags(VIR_DOMAIN_CONSOLE_SAFE | + VIR_DOMAIN_CONSOLE_FORCE, -1); qemuDriverLock(driver); virUUIDFormat(dom->uuid, uuidstr); @@ -11261,6 +11263,8 @@ qemuDomainOpenConsole(virDomainPtr dom, goto cleanup; } + priv = vm->privateData; + if (dev_name) { for (i = 0 ; !chr && i < vm->def->nconsoles ; i++) { if (vm->def->consoles[i]->info.alias && @@ -11296,11 +11300,18 @@ qemuDomainOpenConsole(virDomainPtr dom, goto cleanup; } - if (virFDStreamOpenFile(st, chr->source.data.file.path, - 0, 0, O_RDWR) < 0) - goto cleanup; + /* handle mutually exclusive access to console devices */ + ret = virConsoleOpen(priv->cons, + chr->source.data.file.path, + st, + (flags & VIR_DOMAIN_CONSOLE_FORCE) != 0); + + if (ret == 1) { + qemuReportError(VIR_ERR_OPERATION_FAILED, + _("Active console session exists for this domain")); + ret = -1; + } - ret = 0; cleanup: if (vm) virDomainObjUnlock(vm); -- 1.7.3.4