Date: Thu, 6 Dec 2012 22:57:38 GMT From: Brooks Davis <brooks@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 219893 for review Message-ID: <201212062257.qB6MvctJ064493@skunkworks.freebsd.org>
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http://p4web.freebsd.org/@@219893?ac=10 Change 219893 by brooks@brooks_zenith on 2012/12/06 22:56:43 Resolve a race in starting the shell with sending the first character by starting the shell during the general startup code instead of when the terminal is first used. This should make the race impractical to trigger by accident if not outright impossible. Affected files ... .. //depot/projects/ctsrd/cheribsd/src/ctsrd/pictview/pictview.c#9 edit Differences ... ==== //depot/projects/ctsrd/cheribsd/src/ctsrd/pictview/pictview.c#9 (text+ko) ==== @@ -54,6 +54,8 @@ #include <de4tc.h> #include <imagebox.h> +static void start_keyboard_shell(void); + static pid_t browser_pid; static pid_t kbd_pid; @@ -72,9 +74,10 @@ else { if (pid == browser_pid) browser_pid = 0; - else if (pid == kbd_pid) + else if (pid == kbd_pid) { kbd_pid = 0; - else + kbdfd = -1; + } else warnx("unexpected pid from wait4(): %d", pid); } } @@ -167,6 +170,8 @@ read_png_file("/usr/share/images/keyboardS.png", keyboard_imgs[1], keyboard_width, keyboard_height); read_png_file("/usr/share/images/keyboardN.png", keyboard_imgs[2], keyboard_width, keyboard_height); read_png_file("/usr/share/images/keyboardC.png", keyboard_imgs[3], keyboard_width, keyboard_height); + + start_keyboard_shell(); } static void @@ -184,6 +189,31 @@ } } +static void +start_keyboard_shell(void) +{ + int pmaster, pslave; + + if (openpty(&pmaster, &pslave, NULL, NULL, NULL) == -1) + err(1, "openpty"); + kbd_pid = fork(); + if (kbd_pid < 0) + err(1, "fork()"); + else if (kbd_pid > 0) { + close(pslave); + kbdfd = pmaster; + } else { + close(pmaster); + if (login_tty(pslave) < 0) { + syslog(LOG_ALERT, "login_tty failed in child: %s", strerror(errno)); + err(1, "tty_login"); + } + execl("/bin/sh", "sh", NULL); + syslog(LOG_ALERT, "exec of /bin/sh failed: %s", strerror(errno)); + err(1, "execl()"); + } +} + void keyboard_on(void) { @@ -198,8 +228,7 @@ const int poll_timeout = touch_timeout; int wait_poll_timeout = poll_timeout; - static int pmaster; - int pslave, n; + int n; char *devpath, buf[1024]; ssize_t rlen; struct pollfd pfd[1]; @@ -232,26 +261,8 @@ keymap[1][1][3] = '\xff'; keymap[2][1][3] = '\xff'; - if (kbdfd < 0) { - if (openpty(&pmaster, &pslave, NULL, NULL, NULL) == -1) - err(1, "openpty"); - kbd_pid = fork(); - if (kbd_pid < 0) - err(1, "fork()"); - else if (kbd_pid > 0) { - close(pslave); - kbdfd = pmaster; - } else { - close(pmaster); - if (login_tty(pslave) < 0) { - syslog(LOG_ALERT, "login_tty failed in child: %s", strerror(errno)); - err(1, "tty_login"); - } - execl("/bin/sh", "sh", NULL); - syslog(LOG_ALERT, "exec of /bin/sh failed: %s", strerror(errno)); - err(1, "execl()"); - } - } + if (kbdfd < 0) + start_keyboard_shell(); fb_fade2off(); fb_fade2text(127); @@ -339,7 +350,7 @@ wait_poll_timeout = poll_timeout; /* Check for output from the child and post it if needed */ - pfd[0].fd = pmaster; + pfd[0].fd = kbdfd; pfd[0].events = POLLIN; n = poll(pfd, 1, 0); if (n == 0)
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