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fix: use flock to check dpkg lock instead of ps scan #771

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fix: use flock to check dpkg lock instead of ps scan #771

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35 changes: 18 additions & 17 deletions deepin-devicemanager-server/deepin-devicecontrol/src/drivercontrol/utils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -13,9 +13,10 @@
#include <QFile>
#include <QLoggingCategory>

#include <sys/utsname.h>

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#include <unistd.h>

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#include <fcntl.h>

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#include <sys/file.h>

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using namespace DDLog;

Expand Down Expand Up @@ -231,25 +232,25 @@
return false;
}

bool Utils::isDpkgLocked()

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The function 'isDpkgLocked' is never used.
{
QProcess proc;
proc.setProgram("ps");
proc.setArguments(QStringList() << "-e" << "-o" << "comm");
proc.start();
proc.waitForFinished();
QString info = proc.readAllStandardOutput();
if (!info.contains("dpkg"))
return false;

// Split the output search for the 'grep dpkg ' pattern
foreach (QString out, info.split("\n")) {
if (out.contains("dpkg")) {
if(out.trimmed() == "dpkg-query")
return false;
}
}
return true;
// Check dpkg lock files using non-blocking exclusive flock.
const QStringList lockFiles = {
"/var/lib/dpkg/lock-frontend",
"/var/lib/dpkg/lock"
};
for (const QString &lockFile : lockFiles) {

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Consider using std::any_of algorithm instead of a raw loop.
int fd = open(lockFile.toLocal8Bit().constData(), O_RDONLY | O_CLOEXEC);

@sourcery-ai sourcery-ai Bot Sep 17, 2026

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issue (bug_risk): flock(fd, LOCK_EX | LOCK_NB) fails with EBADF because each lock file is opened with O_RDONLY, while an exclusive flock requires a file descriptor opened for writing. Since every existing dpkg lock file follows this path, isDpkgLocked() returns true even when no dpkg operation is running, causing installation workflows to retry until timeout.

Triggers: When either dpkg lock file exists, including the normal idle system state.

Suggested fix: Open the lock files with a writable mode such as O_RDWR before attempting LOCK_EX, or use a lock-checking operation compatible with the descriptor mode.

Suggested change
int fd = open(lockFile.toLocal8Bit().constData(), O_RDONLY | O_CLOEXEC);
int fd = open(lockFile.toLocal8Bit().constData(), O_RDWR | O_CLOEXEC);

if (fd < 0) {
return true;
}
if (flock(fd, LOCK_EX | LOCK_NB) == -1) {
close(fd);
return true;
}
close(fd);
}
return false;
}

QString Utils::getUrl()
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