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Protect against deadlock when using fam/gamin by adding a small timeout to the peek for events done between add calls. Add alarm to the addwatch call in case the deadlock happens anyway

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This commit is contained in:
Jean-Francois Dockes 2011-10-13 15:20:28 +02:00
parent bed77d3095
commit 56fe54412f
2 changed files with 91 additions and 32 deletions
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11
src/common/rclinit.cpp
View File

@ -50,9 +50,16 @@ RclConfig *recollinit(RclInitFlags flags,
// Install signal handler
if (sigcleanup) {
struct sigaction action;
action.sa_handler = sigcleanup;
action.sa_flags = 0;
sigemptyset(&action.sa_mask);
for (unsigned int i = 0; i < sizeof(catchedSigs) / sizeof(int); i++)
if (signal(catchedSigs[i], SIG_IGN) != SIG_IGN)
signal(catchedSigs[i], sigcleanup);
if (signal(catchedSigs[i], SIG_IGN) != SIG_IGN) {
if (sigaction(catchedSigs[i], &action, 0) < 0) {
perror("Sigaction failed");
}
}
}
DebugLog::getdbl()->setloglevel(DEBDEB1);

112
src/index/rclmonrcv.cpp
View File

@ -40,7 +40,7 @@ public:
RclMonitor(){}
virtual ~RclMonitor() {}
virtual bool addWatch(const string& path, bool isDir) = 0;
virtual bool getEvent(RclMonEvent& ev, int secs = -1) = 0;
virtual bool getEvent(RclMonEvent& ev, int msecs = -1) = 0;
virtual bool ok() const = 0;
// Does this monitor generate 'exist' events at startup?
virtual bool generatesExist() const = 0;
@ -128,7 +128,19 @@ void *rclMonRcvRun(void *q)
LOGDEB(("rclMonRcvRun: running\n"));
recoll_threadinit();
// Make a local copy of the configuration as it doesn't like
// concurrent accesses. It's ok to copy it here as the other
// thread will not work before we have sent events.
RclConfig lconfig(*queue->getConfig());
string loglevel;
lconfig.getConfParam(string("daemloglevel"), loglevel);
if (loglevel.empty())
lconfig.getConfParam(string("loglevel"), loglevel);
if (!loglevel.empty()) {
int lev = atoi(loglevel.c_str());
DebugLog::getdbl()->setloglevel(lev);
}
// Create the fam/whatever interface object
RclMonitor *mon;
@ -138,10 +150,6 @@ void *rclMonRcvRun(void *q)
return 0;
}
// Make a local copy of the configuration as it doesn't like
// concurrent accesses. It's ok to copy it here as the other
// thread will not work before we have sent events.
RclConfig lconfig(*queue->getConfig());
// Get top directories from config
list<string> tdl = lconfig.getTopdirs();
@ -167,16 +175,24 @@ void *rclMonRcvRun(void *q)
walker.setOpts(FsTreeWalker::FtwOptNone);
}
LOGDEB(("rclMonRcvRun: walking %s\n", it->c_str()));
walker.walk(*it, walkcb);
if (walker.walk(*it, walkcb) != FsTreeWalker::FtwOk) {
LOGERR(("rclMonRcvRun: tree walk failed\n"));
goto terminate;
}
}
bool dobeagle = false;
lconfig.getConfParam("processbeaglequeue", &dobeagle);
if (dobeagle) {
string beaglequeuedir;
if (!lconfig.getConfParam("beaglequeuedir", beaglequeuedir))
beaglequeuedir = path_tildexpand("~/.beagle/ToIndex/");
mon->addWatch(beaglequeuedir, true);
{
bool dobeagle = false;
lconfig.getConfParam("processbeaglequeue", &dobeagle);
if (dobeagle) {
string beaglequeuedir;
if (!lconfig.getConfParam("beaglequeuedir", beaglequeuedir))
beaglequeuedir = path_tildexpand("~/.beagle/ToIndex/");
if (!mon->addWatch(beaglequeuedir, true)) {
LOGERR(("rclMonRcvRun: addwatch (beaglequeuedit) failed\n"));
goto terminate;
}
}
}
// Forever wait for monitoring events and add them to queue:
@ -188,7 +204,7 @@ void *rclMonRcvRun(void *q)
// (it goes to the main thread, from which I tried to close or
// write to the select fd, with no effect). So set a
// timeout so that an intr will be detected
if (mon->getEvent(ev, 2)) {
if (mon->getEvent(ev, 2000)) {
if (ev.m_etyp == RclMonEvent::RCLEVT_DIRCREATE) {
// Recursive addwatch: there may already be stuff
// inside this directory. Ie: files were quickly
@ -201,7 +217,11 @@ void *rclMonRcvRun(void *q)
!walker.inSkippedPaths(ev.m_path)) {
LOGDEB(("rclMonRcvRun: walking new dir %s\n",
ev.m_path.c_str()));
walker.walk(ev.m_path, walkcb);
if (walker.walk(ev.m_path, walkcb) != FsTreeWalker::FtwOk) {
LOGERR(("rclMonRcvRun: failed walking new dir %s\n",
ev.m_path.c_str()));
goto terminate;
}
}
}
@ -210,6 +230,7 @@ void *rclMonRcvRun(void *q)
}
}
terminate:
queue->setTerminate();
LOGINFO(("rclMonRcvRun: monrcv thread routine returning\n"));
return 0;
@ -241,6 +262,9 @@ bool eraseWatchSubTree(map<int, string>& idtopath, const string& top)
/** Fam/gamin -based monitor class */
#include <fam.h>
#include <sys/select.h>
#include <setjmp.h>
#include <unistd.h>
#include <signal.h>
/** FAM based monitor class. We have to keep a record of FAM watch
request numbers to directory names as the event only contain the
@ -250,7 +274,7 @@ public:
RclFAM();
virtual ~RclFAM();
virtual bool addWatch(const string& path, bool isdir);
virtual bool getEvent(RclMonEvent& ev, int secs = -1);
virtual bool getEvent(RclMonEvent& ev, int msecs = -1);
bool ok() const {return m_ok;}
virtual bool generatesExist() const {return true;}
@ -305,30 +329,53 @@ RclFAM::~RclFAM()
FAMClose(&m_conn);
}
static jmp_buf jbuf;
static void onalrm(int sig)
{
longjmp(jbuf, 1);
}
bool RclFAM::addWatch(const string& path, bool isdir)
{
if (!ok())
return false;
bool ret = false;
MONDEB(("RclFAM::addWatch: adding %s\n", path.c_str()));
// It happens that the following call block forever.
// We'd like to be able to at least terminate on a signal here, but
// gamin forever retries its write call on EINTR, so it's not even useful
// to unblock signals. SIGALRM is not used by the main thread, so at least
// ensure that we exit after gamin gets stuck.
if (setjmp(jbuf)) {
LOGERR(("RclFAM::addWatch: timeout talking to FAM\n"));
return false;
}
signal(SIGALRM, onalrm);
alarm(20);
FAMRequest req;
if (isdir) {
if (FAMMonitorDirectory(&m_conn, path.c_str(), &req, 0) != 0) {
LOGERR(("RclFAM::addWatch: FAMMonitorDirectory failed\n"));
return false;
goto out;
}
} else {
if (FAMMonitorFile(&m_conn, path.c_str(), &req, 0) != 0) {
LOGERR(("RclFAM::addWatch: FAMMonitorFile failed\n"));
return false;
goto out;
}
}
m_idtopath[req.reqnum] = path;
return true;
ret = true;
out:
alarm(0);
return ret;
}
// Note: return false only for queue empty or error
// Return EVT_NONE for bad event to keep queue processing going
bool RclFAM::getEvent(RclMonEvent& ev, int secs)
bool RclFAM::getEvent(RclMonEvent& ev, int msecs)
{
if (!ok())
return false;
@ -340,13 +387,18 @@ bool RclFAM::getEvent(RclMonEvent& ev, int secs)
FD_SET(fam_fd, &readfds);
MONDEB(("RclFAM::getEvent: select. fam_fd is %d\n", fam_fd));
// Fam / gamin is sometimes a bit slow to send events. Always add
// a little timeout, because if we fail to retrieve enough events,
// we risk deadlocking in addwatch()
if (msecs == 0)
msecs = 2;
struct timeval timeout;
if (secs >= 0) {
memset(&timeout, 0, sizeof(timeout));
timeout.tv_sec = secs;
if (msecs >= 0) {
timeout.tv_sec = msecs / 1000;
timeout.tv_usec = (msecs % 1000) * 1000;
}
int ret;
if ((ret=select(fam_fd+1, &readfds, 0, 0, secs >= 0 ? &timeout : 0)) < 0) {
if ((ret=select(fam_fd+1, &readfds, 0, 0, msecs >= 0 ? &timeout : 0)) < 0) {
LOGERR(("RclFAM::getEvent: select failed, errno %d\n", errno));
close();
return false;
@ -455,7 +507,7 @@ public:
}
virtual bool addWatch(const string& path, bool isdir);
virtual bool getEvent(RclMonEvent& ev, int secs = -1);
virtual bool getEvent(RclMonEvent& ev, int msecs = -1);
bool ok() const {return m_ok;}
virtual bool generatesExist() const {return false;}
@ -532,7 +584,7 @@ bool RclIntf::addWatch(const string& path, bool)
// Note: return false only for queue empty or error
// Return EVT_NONE for bad event to keep queue processing going
bool RclIntf::getEvent(RclMonEvent& ev, int secs)
bool RclIntf::getEvent(RclMonEvent& ev, int msecs)
{
if (!ok())
return false;
@ -544,13 +596,13 @@ bool RclIntf::getEvent(RclMonEvent& ev, int secs)
FD_ZERO(&readfds);
FD_SET(m_fd, &readfds);
struct timeval timeout;
if (secs >= 0) {
memset(&timeout, 0, sizeof(timeout));
timeout.tv_sec = secs;
if (msecs >= 0) {
timeout.tv_sec = msecs / 1000;
timeout.tv_usec = (msecs % 1000) * 1000;
}
int ret;
MONDEB(("RclIntf::getEvent: select\n"));
if ((ret=select(m_fd + 1, &readfds, 0, 0, secs >= 0 ? &timeout : 0)) < 0) {
if ((ret=select(m_fd + 1, &readfds, 0, 0, msecs >= 0 ? &timeout : 0)) < 0) {
LOGERR(("RclIntf::getEvent: select failed, errno %d\n", errno));
close();
return false;