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Commit 0558e582 authored by Yifan Hong's avatar Yifan Hong
Browse files

CgroupSetupCgroups: don't leak fd. 

- If file is unlinked, the mmapped region is still there.
- If file is truncated, a SIGBUS will be seen, and holding
  the fd doesn't help.

Test: boots (sanity)
Bug: 123664216
Change-Id: I6683804bc795fab6798891a4471e5fe58fbffe13
Merged-In: I6683804bc795fab6798891a4471e5fe58fbffe13
parent d5887289

libprocessgroup/setup/cgroup_map_write.cpp

+2 −7
Original line number Diff line number Diff line
@@ -235,14 +235,9 @@ static bool SetupCgroup(const CgroupDescriptor&) { 


#endif



// WARNING: This function should be called only from SetupCgroups and only once.

// It intentionally leaks an FD, so additional invocation will result in additional leak.

static bool WriteRcFile(const std::map<std::string, CgroupDescriptor>& descriptors) {

    // WARNING: We are intentionally leaking the FD to keep the file open forever.

    // Let init keep the FD open to prevent file mappings from becoming invalid in

    // case the file gets deleted somehow.

    int fd = TEMP_FAILURE_RETRY(open(CGROUPS_RC_PATH, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC,

                                     S_IRUSR | S_IRGRP | S_IROTH));

    unique_fd fd(TEMP_FAILURE_RETRY(open(CGROUPS_RC_PATH, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC,

                                         S_IRUSR | S_IRGRP | S_IROTH)));

    if (fd < 0) {

        PLOG(ERROR) << "open() failed for " << CGROUPS_RC_PATH;

        return false;