From 870a2b6d683e58c0584bbd3614a76cf25a055928 Mon Sep 17 00:00:00 2001 From: Julian Andres Klode Date: Mon, 25 May 2015 16:45:05 +0200 Subject: ExecFork: Use /proc/self/fd to determine which files to close This significantly reduces the number of files that have to be closed and seems to be faster, despite the additional reads. On systems where /proc/self/fd is not available, we fallback to the old code that closes all file descriptors >= 3. Closes: #764204 --- apt-pkg/contrib/fileutl.cc | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc index 1e6d96fe9..6e34f5d28 100644 --- a/apt-pkg/contrib/fileutl.cc +++ b/apt-pkg/contrib/fileutl.cc @@ -778,12 +778,26 @@ pid_t ExecFork(std::set KeepFDs) signal(SIGCONT,SIG_DFL); signal(SIGTSTP,SIG_DFL); - long ScOpenMax = sysconf(_SC_OPEN_MAX); - // Close all of our FDs - just in case - for (int K = 3; K != ScOpenMax; K++) + DIR *dir = opendir("/proc/self/fd"); + if (dir != NULL) { - if(KeepFDs.find(K) == KeepFDs.end()) - fcntl(K,F_SETFD,FD_CLOEXEC); + struct dirent *ent; + while ((ent = readdir(dir))) + { + int fd = atoi(ent->d_name); + // If fd > 0, it was a fd number and not . or .. + if (fd >= 3 && KeepFDs.find(fd) == KeepFDs.end()) + fcntl(fd,F_SETFD,FD_CLOEXEC); + } + closedir(dir); + } else { + long ScOpenMax = sysconf(_SC_OPEN_MAX); + // Close all of our FDs - just in case + for (int K = 3; K != ScOpenMax; K++) + { + if(KeepFDs.find(K) == KeepFDs.end()) + fcntl(K,F_SETFD,FD_CLOEXEC); + } } } -- cgit v1.2.3