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authorJulian Andres Klode <julian.klode@canonical.com>2019-06-21 22:45:13 +0200
committerJulian Andres Klode <julian.klode@canonical.com>2019-06-21 23:14:46 +0200
commitcde8399310e56faaa6928411392184bc403eff66 (patch)
tree4001440b885ffacbfb314fa8380e8b2bd2da7f5b /apt-pkg/contrib
parent67b51af0f9c7cab4d827ac1e63f8a83d03e2f23c (diff)
Improve locking messaging - pid and name, "do not remove lock file"
We want to tell users which process is holding the lock so they can easily understand what's going on, and we want to advise users not to remove the lock file, because ugh, that's bad. Re-initalize the flock structure, in case it got mangled by previous fcntl call.
Diffstat (limited to 'apt-pkg/contrib')
-rw-r--r--apt-pkg/contrib/fileutl.cc55
1 files changed, 53 insertions, 2 deletions
diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index 798636647..336f979d6 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -223,6 +223,30 @@ bool RemoveFile(char const * const Function, std::string const &FileName)/*{{{*/
is done all other calls to GetLock in any other process will fail with
-1. The return result is the fd of the file, the call should call
close at some time. */
+
+static std::string GetProcessName(int pid)
+{
+ struct HideError
+ {
+ int err;
+ HideError() : err(errno) { _error->PushToStack(); }
+ ~HideError()
+ {
+ errno = err;
+ _error->RevertToStack();
+ }
+ } hideError;
+ std::string path;
+ strprintf(path, "/proc/%d/status", pid);
+ FileFd status(path, FileFd::ReadOnly);
+ std::string line;
+ while (status.ReadLine(line))
+ {
+ if (line.substr(0, 5) == "Name:")
+ return line.substr(6);
+ }
+ return "";
+}
int GetLock(string File,bool Errors)
{
// GetLock() is used in aptitude on directories with public-write access
@@ -256,6 +280,20 @@ int GetLock(string File,bool Errors)
{
// always close to not leak resources
int Tmp = errno;
+
+ if ((errno == EACCES || errno == EAGAIN))
+ {
+ fl.l_type = F_WRLCK;
+ fl.l_whence = SEEK_SET;
+ fl.l_start = 0;
+ fl.l_len = 0;
+ fl.l_pid = -1;
+ fcntl(FD, F_GETLK, &fl);
+ }
+ else
+ {
+ fl.l_pid = -1;
+ }
close(FD);
errno = Tmp;
@@ -266,8 +304,21 @@ int GetLock(string File,bool Errors)
}
if (Errors == true)
- _error->Errno("open",_("Could not get lock %s"),File.c_str());
-
+ {
+ if (fl.l_pid != -1)
+ {
+ auto name = GetProcessName(fl.l_pid);
+ if (name.empty())
+ _error->Errno("open", _("Could not get lock %s. It is held by process %d"), File.c_str(), fl.l_pid);
+ else
+ _error->Errno("open", _("Could not get lock %s. It is held by process %d (%s)"), File.c_str(), fl.l_pid, name.c_str());
+ }
+ else
+ _error->Errno("open", _("Could not get lock %s"), File.c_str());
+
+ _error->Notice(_("Be aware that removing the lock file is not a solution and may break your system."));
+ }
+
return -1;
}