diff options
| -rw-r--r-- | src/main/cpp/blaze_util_posix.cc | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/src/main/cpp/blaze_util_posix.cc b/src/main/cpp/blaze_util_posix.cc index 5ab7a6630f..99070d47f8 100644 --- a/src/main/cpp/blaze_util_posix.cc +++ b/src/main/cpp/blaze_util_posix.cc @@ -12,6 +12,7 @@ // See the License for the specific language governing permissions and // limitations under the License. +#include <dirent.h> #include <errno.h> #include <fcntl.h> #include <limits.h> // PATH_MAX @@ -39,6 +40,7 @@ namespace blaze { using blaze_util::die; using blaze_util::pdie; +using blaze_exit_code::INTERNAL_ERROR; using std::string; using std::vector; @@ -170,6 +172,35 @@ bool SymlinkDirectories(const string &target, const string &link) { return symlink(target.c_str(), link.c_str()) == 0; } +static void CheckSingleThreaded() { +#ifdef __linux__ + DIR *dir = opendir("/proc/self/task"); + if (!dir) pdie(INTERNAL_ERROR, "can't list /proc/self/task"); + vector<string> tids; + while (dirent *dent = readdir(dir)) { + if (dent->d_name[0] != '.') tids.push_back(dent->d_name); + } + closedir(dir); + if (tids.size() == 1) return; + + // If there are multiple threads, show their names as a debugging aid. + fprintf(stderr, "Trying to fork, but found %zu threads:\n", tids.size()); + for (const string &t : tids) { + string path = string("/proc/self/task/") + t + "/comm"; + if (FILE *f = fopen(path.c_str(), "r")) { + char comm[4096]; + int len = fread(comm, 1, sizeof comm, f); + fprintf(stderr, " Thread %s: %.*s", t.c_str(), len, comm); + fclose(f); + } else { + fprintf(stderr, "can't open %s", path.c_str()); + } + } + die(INTERNAL_ERROR, "can't fork() after creating threads"); +#endif + // This can probably be checked on darwin via <sys/proc_info.h>. +} + // Causes the current process to become a daemon (i.e. a child of // init, detached from the terminal, in its own session.) We don't // change cwd, though. @@ -179,6 +210,7 @@ static void Daemonize(const string& daemon_output) { // anything that can possibly fail. :) signal(SIGHUP, SIG_IGN); + CheckSingleThreaded(); if (fork() > 0) { // This second fork is required iff there's any chance cmd will // open an specific tty explicitly, e.g., open("/dev/tty23"). If @@ -238,6 +270,7 @@ void ExecuteDaemon(const string& exe, if (pipe(fds)) { pdie(blaze_exit_code::INTERNAL_ERROR, "pipe creation failed"); } + CheckSingleThreaded(); int child = fork(); if (child == -1) { pdie(blaze_exit_code::INTERNAL_ERROR, "fork() failed"); @@ -276,6 +309,7 @@ static string RunProgram(const string& exe, int recv_socket = fds[0]; int send_socket = fds[1]; + CheckSingleThreaded(); int child = fork(); if (child == -1) { pdie(blaze_exit_code::INTERNAL_ERROR, "fork() failed"); |