daandemeyer / rpms / systemd

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From 067fbebee46a376c639c9369dcaf80004047414d Mon Sep 17 00:00:00 2001
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From: Lennart Poettering <lennart@poettering.net>
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Date: Mon, 3 Aug 2015 19:04:08 +0200
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Subject: [PATCH] terminal-util: when resetting terminals, don't wait for
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 carrier
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In case of non-CLOCAL lines (i.e. those with carrier detect configured)
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we shouldnt wait for a carrier if all we try to do is reset the TTY.
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Hence, whenever we open such a TTY pass O_NONBLOCK.
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Note that we continue to open ttys we intend to write to without
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O_ONBLOCK, we only add it in cases we invoke ioctl()s or other terminal
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operations without reading or writing to the device.
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Fixes #835.
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Cherry-picked from: 0a8b555ceb07ce916b9bd48782d1eb69a12f0f2e
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Resolves: #1266745
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---
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 src/shared/util.c | 14 +++++++++-----
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 1 file changed, 9 insertions(+), 5 deletions(-)
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diff --git a/src/shared/util.c b/src/shared/util.c
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index 778c2b0e0..50925888d 100644
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--- a/src/shared/util.c
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+++ b/src/shared/util.c
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@@ -1713,7 +1713,7 @@ bool fstype_is_network(const char *fstype) {
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 int chvt(int vt) {
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         _cleanup_close_ int fd;
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-        fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC);
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+        fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
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         if (fd < 0)
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                 return -errno;
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@@ -1953,7 +1953,11 @@ finish:
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 int reset_terminal(const char *name) {
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         _cleanup_close_ int fd = -1;
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-        fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
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+        /* We open the terminal with O_NONBLOCK here, to ensure we
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+         * don't block on carrier if this is a terminal with carrier
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+         * configured. */
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+
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+        fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
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         if (fd < 0)
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                 return fd;
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@@ -2204,7 +2208,7 @@ int release_terminal(void) {
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         struct sigaction sa_old;
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         int r = 0;
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-        fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_NDELAY|O_CLOEXEC);
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+        fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
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         if (fd < 0)
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                 return -errno;
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@@ -4405,7 +4409,7 @@ int terminal_vhangup_fd(int fd) {
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 int terminal_vhangup(const char *name) {
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         _cleanup_close_ int fd;
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-        fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
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+        fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
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         if (fd < 0)
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                 return fd;
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@@ -4452,7 +4456,7 @@ int vt_disallocate(const char *name) {
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                 return -EINVAL;
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         /* Try to deallocate */
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-        fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC);
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+        fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
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         if (fd < 0)
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                 return fd;
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