From 699cafe0aea5a92c82e9f8ded0d7213666ffb1d3 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Sun, 29 Dec 2013 06:32:59 +0000 Subject: [PATCH] avoid redundant F_GETFD when O_CLOEXEC works It is pointless to check if O_CLOEXEC works after every single open() call. If the kernel supports O_CLOEXEC for one open(), it is supported for every open() syscall. --- io.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) diff --git a/io.c b/io.c index 5aa720b..6197243 100644 --- a/io.c +++ b/io.c @@ -224,10 +224,29 @@ rb_fd_fix_cloexec(int fd) rb_update_max_fd(fd); } +/* this is only called once */ +static int +rb_fix_detect_o_cloexec(int fd) +{ +#ifdef O_CLOEXEC + int flags = fcntl(fd, F_GETFD); + + if (flags == -1) + rb_bug("rb_fix_detect_o_cloexec: fcntl(%d, F_GETFD) failed: %s", fd, strerror(errno)); + + if (flags & FD_CLOEXEC) + return 1; +#endif /* fall through if O_CLOEXEC does not work: */ + rb_maygvl_fd_fix_cloexec(fd); + return 0; +} + int rb_cloexec_open(const char *pathname, int flags, mode_t mode) { int ret; + static int o_cloexec_state = -1; /* <0: unknown, 0: ignored, >0: working */ + #ifdef O_CLOEXEC /* O_CLOEXEC is available since Linux 2.6.23. Linux 2.6.18 silently ignore it. */ flags |= O_CLOEXEC; @@ -236,7 +255,13 @@ rb_cloexec_open(const char *pathname, int flags, mode_t mode) #endif ret = open(pathname, flags, mode); if (ret == -1) return -1; - rb_maygvl_fd_fix_cloexec(ret); + if (ret <= 2 || o_cloexec_state == 0) { + rb_maygvl_fd_fix_cloexec(ret); + } else if (o_cloexec_state > 0) { + return ret; + } else { + o_cloexec_state = rb_fix_detect_o_cloexec(ret); + } return ret; } -- 1.8.3.2.701.g8c4e4ec