script: remove magic constants from poll code

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/term-utils/script.c b/term-utils/script.c
index 1cb0a653dce838ff8dc74e7c08687534e9b0c975..99ea7293c53c467c1a1de1c5c68895d395e08e07 100644 (file)
--- a/term-utils/script.c
+++ b/term-utils/script.c
@@ -80,8 +80,6 @@
 
 #define DEFAULT_TYPESCRIPT_FILENAME "typescript"
 
-enum { POLLFDS = 3 };
-
 struct script_control {
        char *shell;            /* shell to be executed */
        char *command;          /* command to be executed */
@@ -234,18 +232,21 @@ static void write_output(struct script_control *ctl, char *obuf,
        }
 }
 
-static void handle_io(struct script_control *ctl, int fd, int i)
+static void handle_io(struct script_control *ctl, int fd)
 {
        char buf[BUFSIZ];
        ssize_t bytes;
 
+       /* read from active FD */
        bytes = read(fd, buf, sizeof(buf));
        if (bytes < 0) {
                if (errno == EAGAIN)
                        return;
                fail(ctl);
        }
-       if (i == 0) {
+
+       /* from stdin (user) to command */
+       if (fd == STDIN_FILENO) {
                if (write_all(ctl->master, buf, bytes)) {
                        warn(_("write failed"));
                        fail(ctl);
@@ -257,7 +258,9 @@ static void handle_io(struct script_control *ctl, int fd, int i)
                        char c = DEF_EOF;
                        write_all(ctl->master, &c, sizeof(char));
                }
-       } else
+
+       /* from command (master) to stdout */
+       } else if (fd == ctl->master)
                write_output(ctl, buf, bytes);
 }
 
@@ -268,6 +271,7 @@ static void handle_signal(struct script_control *ctl, int fd)
 
        bytes = read(fd, &info, sizeof(info));
        assert(bytes == sizeof(info));
+
        switch (info.ssi_signo) {
        case SIGCHLD:
                finish(ctl, 0);
@@ -286,10 +290,20 @@ static void handle_signal(struct script_control *ctl, int fd)
 
 static void do_io(struct script_control *ctl)
 {
-       struct pollfd pfd[POLLFDS];
-       int ret, i;
+       int ret;
        time_t tvec = script_time((time_t *)NULL);
        char buf[128];
+       enum {
+               POLLFD_STDIN = 0,
+               POLLFD_MASTER,
+               POLLFD_SIGNAL,
+       };
+       struct pollfd pfd[] = {
+               [POLLFD_STDIN]  { .fd = STDIN_FILENO, .events = POLLIN },
+               [POLLFD_MASTER] { .fd = ctl->master,  .events = POLLIN },
+               [POLLFD_SIGNAL] { .fd = ctl->sigfd,   .events = POLLIN | POLLERR | POLLHUP }
+       };
+
 
        if ((ctl->typescriptfp = fopen(ctl->fname, ctl->append ? "a" : "w")) == NULL) {
                warn(_("cannot open %s"), ctl->fname);
@@ -303,20 +317,15 @@ static void do_io(struct script_control *ctl)
                        err(EXIT_FAILURE, _("cannot open %s"), ctl->tname);
        }
 
-       pfd[0].fd = STDIN_FILENO;
-       pfd[0].events = POLLIN;
-       pfd[1].fd = ctl->master;
-       pfd[1].events = POLLIN;
-       pfd[2].fd = ctl->sigfd;
-       pfd[2].events = POLLIN | POLLERR | POLLHUP;
-
        strftime(buf, sizeof buf, "%c\n", localtime(&tvec));
        fprintf(ctl->typescriptfp, _("Script started on %s"), buf);
        gettime_monotonic(&ctl->oldtime);
 
        while (!ctl->die) {
+               size_t i;
+
                /* wait for input or signal */
-               ret = poll(pfd, POLLFDS, ctl->poll_timeout);
+               ret = poll(pfd, ARRAY_SIZE(pfd), ctl->poll_timeout);
                if (ret < 0) {
                        if (errno == EAGAIN)
                                continue;
@@ -325,20 +334,23 @@ static void do_io(struct script_control *ctl)
                }
                if (ret == 0)
                        ctl->die = 1;
-               for (i = 0; i < POLLFDS; i++) {
+
+               for (i = 0; i < ARRAY_SIZE(pfd); i++) {
                        if (pfd[i].revents == 0)
                                continue;
-                       if (i < 2) {
-                               handle_io(ctl, pfd[i].fd, i);
+                       switch (i) {
+                       case POLLFD_STDIN:
+                       case POLLFD_MASTER:
+                               handle_io(ctl, pfd[i].fd);
                                continue;
-                       }
-                       if (i == 2) {
+                       case POLLFD_SIGNAL:
                                handle_signal(ctl, pfd[i].fd);
                                if (!ctl->isterm && -1 < ctl->poll_timeout)
                                        /* In situation such as 'date' in
                                        * $ echo date | ./script
                                        * ignore input when shell has exited.  */
-                                       pfd[0].fd = -1;
+                                       pfd[POLLFD_STDIN].fd = -1;
+                               break;
                        }
                }
        }