git: 407e3790c3a0 - main - daemon: separate pipe_fd[2] into pipe_rd and pipe_wr

[Kyle Evans]

The branch main has been updated by kevans:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=407e3790c3a0652beb5c97e4049a58a6e2118ce4

commit 407e3790c3a0652beb5c97e4049a58a6e2118ce4
Author:     Ihor Antonov <ihor@antonovs.family>
AuthorDate: 2023-12-27 06:07:26 +0000
Commit:     Kyle Evans <kev...@freebsd.org>
CommitDate: 2023-12-27 06:07:26 +0000

    daemon: separate pipe_fd[2] into pipe_rd and pipe_wr
    
    This improves code readability and prevents mixing up read and write
    ends of the pipe.
    
    Reviewed by:    cperciva, kevans
    Requested by:   kevans
---
 usr.sbin/daemon/daemon.c | 44 +++++++++++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/usr.sbin/daemon/daemon.c b/usr.sbin/daemon/daemon.c
index 066240fc8302..f349a382edd2 100644
--- a/usr.sbin/daemon/daemon.c
+++ b/usr.sbin/daemon/daemon.c
@@ -65,10 +65,10 @@ enum daemon_mode {
        MODE_NOCHILD,      /* child is terminated, final state of the event 
loop */
 };
 
+
 struct daemon_state {
        unsigned char buf[LBUF_SIZE];
        size_t pos;
-       int pipe_fd[2];
        char **argv;
        const char *child_pidfile;
        const char *parent_pidfile;
@@ -80,6 +80,8 @@ struct daemon_state {
        struct pidfh *child_pidfh;
        enum daemon_mode mode;
        int pid;
+       int pipe_rd;
+       int pipe_wr;
        int keep_cur_workdir;
        int restart_delay;
        int stdmask;
@@ -367,6 +369,7 @@ daemon_eventloop(struct daemon_state *state)
        struct kevent event;
        int kq;
        int ret;
+       int pipe_fd[2];
 
        /*
         * Try to protect against pageout kill. Ignore the
@@ -375,12 +378,14 @@ daemon_eventloop(struct daemon_state *state)
         */
        (void)madvise(NULL, 0, MADV_PROTECT);
 
-       if (pipe(state->pipe_fd)) {
+       if (pipe(pipe_fd)) {
                err(1, "pipe");
        }
+       state->pipe_rd = pipe_fd[0];
+       state->pipe_wr = pipe_fd[1];
 
        kq = kqueuex(KQUEUE_CLOEXEC);
-       EV_SET(&event, state->pipe_fd[0], EVFILT_READ, EV_ADD|EV_CLEAR, 0, 0,
+       EV_SET(&event, state->pipe_rd, EVFILT_READ, EV_ADD|EV_CLEAR, 0, 0,
            NULL);
        if (kevent(kq, &event, 1, NULL, 0, NULL) == -1) {
                err(EXIT_FAILURE, "failed to register kevent");
@@ -420,8 +425,8 @@ daemon_eventloop(struct daemon_state *state)
        }
 
        /* case: pid > 0; fork succeeded */
-       close(state->pipe_fd[1]);
-       state->pipe_fd[1] = -1;
+       close(state->pipe_wr);
+       state->pipe_wr = -1;
        setproctitle("%s[%d]", state->title, (int)state->pid);
        setbuf(stdout, NULL);
 
@@ -495,8 +500,8 @@ daemon_eventloop(struct daemon_state *state)
        }
 
        close(kq);
-       close(state->pipe_fd[0]);
-       state->pipe_fd[0] = -1;
+       close(state->pipe_rd);
+       state->pipe_rd = -1;
 }
 
 static void
@@ -592,7 +597,7 @@ listen_child(struct daemon_state *state)
        assert(state != NULL);
        assert(state->pos < LBUF_SIZE - 1);
 
-       rv = read(state->pipe_fd[0], state->buf + state->pos, LBUF_SIZE - 
state->pos - 1);
+       rv = read(state->pipe_rd, state->buf + state->pos, LBUF_SIZE - 
state->pos - 1);
        if (rv > 0) {
                state->pos += rv;
                assert(state->pos <= LBUF_SIZE - 1);
@@ -691,7 +696,6 @@ daemon_state_init(struct daemon_state *state)
        *state = (struct daemon_state) {
                .buf = {0},
                .pos = 0,
-               .pipe_fd = { -1, -1 },
                .argv = NULL,
                .parent_pidfh = NULL,
                .child_pidfh = NULL,
@@ -702,6 +706,8 @@ daemon_state_init(struct daemon_state *state)
                .mode = MODE_DAEMON,
                .restart_enabled = false,
                .pid = 0,
+               .pipe_rd = -1,
+               .pipe_wr = -1,
                .keep_cur_workdir = 1,
                .restart_delay = 1,
                .stdmask = STDOUT_FILENO | STDERR_FILENO,
@@ -724,12 +730,12 @@ daemon_terminate(struct daemon_state *state)
        if (state->output_fd >= 0) {
                close(state->output_fd);
        }
-       if (state->pipe_fd[0] >= 0) {
-               close(state->pipe_fd[0]);
+       if (state->pipe_rd >= 0) {
+               close(state->pipe_rd);
        }
 
-       if (state->pipe_fd[1] >= 0) {
-               close(state->pipe_fd[1]);
+       if (state->pipe_wr >= 0) {
+               close(state->pipe_wr);
        }
        if (state->syslog_enabled) {
                closelog();
@@ -769,20 +775,20 @@ static void
 daemon_set_child_pipe(struct daemon_state *state)
 {
        if (state->stdmask & STDERR_FILENO) {
-               if (dup2(state->pipe_fd[1], STDERR_FILENO) == -1) {
+               if (dup2(state->pipe_wr, STDERR_FILENO) == -1) {
                        err(1, "dup2");
                }
        }
        if (state->stdmask & STDOUT_FILENO) {
-               if (dup2(state->pipe_fd[1], STDOUT_FILENO) == -1) {
+               if (dup2(state->pipe_wr, STDOUT_FILENO) == -1) {
                        err(1, "dup2");
                }
        }
-       if (state->pipe_fd[1] != STDERR_FILENO &&
-           state->pipe_fd[1] != STDOUT_FILENO) {
-               close(state->pipe_fd[1]);
+       if (state->pipe_wr != STDERR_FILENO &&
+           state->pipe_wr != STDOUT_FILENO) {
+               close(state->pipe_wr);
        }
 
        /* The child gets dup'd pipes. */
-       close(state->pipe_fd[0]);
+       close(state->pipe_rd);
 }