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Merge pull request #19591 from poettering/terminal-fixes

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five terminal handling fixes
This commit is contained in:
Lennart Poettering
2021-05-20 07:33:21 +02:00
committed by GitHub
parent 2d4efd1dba 11f3c130aa
commit 48b4a760c9
3 changed files with 117 additions and 53 deletions
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src/basic/terminal-util.c
+63 -43
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@@ -37,6 +37,7 @@
#include "process-util.h"
#include "socket-util.h"
#include "stat-util.h"
#include "stdio-util.h"
#include "string-util.h"
#include "strv.h"
#include "terminal-util.h"
@@ -240,22 +241,27 @@ int reset_terminal_fd(int fd, bool switch_to_text) {
assert(fd >= 0);
/* We leave locked terminal attributes untouched, so that
* Plymouth may set whatever it wants to set, and we don't
* interfere with that. */
if (isatty(fd) < 1)
return log_debug_errno(errno, "Asked to reset a terminal that actually isn't a terminal: %m");
/* We leave locked terminal attributes untouched, so that Plymouth may set whatever it wants to set,
* and we don't interfere with that. */
/* Disable exclusive mode, just in case */
(void) ioctl(fd, TIOCNXCL);
if (ioctl(fd, TIOCNXCL) < 0)
log_debug_errno(errno, "TIOCNXCL ioctl failed on TTY, ignoring: %m");
/* Switch to text mode */
if (switch_to_text)
(void) ioctl(fd, KDSETMODE, KD_TEXT);
if (ioctl(fd, KDSETMODE, KD_TEXT) < 0)
log_debug_errno(errno, "KDSETMODE ioctl for switching to text mode failed on TTY, ignoring: %m");
/* Set default keyboard mode */
(void) vt_reset_keyboard(fd);
if (tcgetattr(fd, &termios) < 0) {
r = -errno;
r = log_debug_errno(errno, "Failed to get terminal parameters: %m");
goto finish;
}
@@ -311,14 +317,13 @@ int reset_terminal(const char *name) {
}
int open_terminal(const char *name, int mode) {
_cleanup_close_ int fd = -1;
unsigned c = 0;
int fd;
/*
* If a TTY is in the process of being closed opening it might
* cause EIO. This is horribly awful, but unlikely to be
* changed in the kernel. Hence we work around this problem by
* retrying a couple of times.
* If a TTY is in the process of being closed opening it might cause EIO. This is horribly awful, but
* unlikely to be changed in the kernel. Hence we work around this problem by retrying a couple of
* times.
*
* https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
*/
@@ -338,16 +343,14 @@ int open_terminal(const char *name, int mode) {
if (c >= 20)
return -errno;
usleep(50 * USEC_PER_MSEC);
(void) usleep(50 * USEC_PER_MSEC);
c++;
}
if (isatty(fd) <= 0) {
safe_close(fd);
return -ENOTTY;
}
if (isatty(fd) < 1)
return negative_errno();
return fd;
return TAKE_FD(fd);
}
int acquire_terminal(
@@ -960,7 +963,9 @@ int get_ctty_devnr(pid_t pid, dev_t *d) {
}
int get_ctty(pid_t pid, dev_t *ret_devnr, char **ret) {
_cleanup_free_ char *fn = NULL, *b = NULL;
char pty[STRLEN("/dev/pts/") + DECIMAL_STR_MAX(dev_t) + 1];
_cleanup_free_ char *buf = NULL;
const char *fn = NULL, *w;
dev_t devnr;
int r;
@@ -968,44 +973,53 @@ int get_ctty(pid_t pid, dev_t *ret_devnr, char **ret) {
if (r < 0)
return r;
r = device_path_make_canonical(S_IFCHR, devnr, &fn);
r = device_path_make_canonical(S_IFCHR, devnr, &buf);
if (r < 0) {
struct stat st;
if (r != -ENOENT) /* No symlink for this in /dev/char/? */
return r;
if (major(devnr) == 136) {
/* This is an ugly hack: PTY devices are not listed in /dev/char/, as they don't follow the
* Linux device model. This means we have no nice way to match them up against their actual
* device node. Let's hence do the check by the fixed, assigned major number. Normally we try
* to avoid such fixed major/minor matches, but there appears to nother nice way to handle
* this. */
/* Maybe this is PTY? PTY devices are not listed in /dev/char/, as they don't follow the
* Linux device model and hence device_path_make_canonical() doesn't work for them. Let's
* assume this is a PTY for a moment, and check if the device node this would then map to in
* /dev/pts/ matches the one we are looking for. This way we don't have to hardcode the major
* number (which is 136 btw), but we still rely on the fact that PTY numbers map directly to
* the minor number of the pty. */
xsprintf(pty, "/dev/pts/%u", minor(devnr));
if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
return -ENOMEM;
} else {
/* Probably something similar to the ptys which have no symlink in /dev/char/. Let's return
* something vaguely useful. */
if (stat(pty, &st) < 0) {
if (errno != ENOENT)
return -errno;
r = device_path_make_major_minor(S_IFCHR, devnr, &fn);
} else if (S_ISCHR(st.st_mode) && devnr == st.st_rdev) /* Bingo! */
fn = pty;
if (!fn) {
/* Doesn't exist, or not a PTY? Probably something similar to the PTYs which have no
* symlink in /dev/char/. Let's return something vaguely useful. */
r = device_path_make_major_minor(S_IFCHR, devnr, &buf);
if (r < 0)
return r;
fn = buf;
}
}
} else
fn = buf;
if (!b) {
const char *w;
w = path_startswith(fn, "/dev/");
if (!w)
return -EINVAL;
w = path_startswith(fn, "/dev/");
if (w) {
b = strdup(w);
if (!b)
return -ENOMEM;
} else
b = TAKE_PTR(fn);
}
if (ret) {
_cleanup_free_ char *b = NULL;
b = strdup(w);
if (!b)
return -ENOMEM;
if (ret)
*ret = TAKE_PTR(b);
}
if (ret_devnr)
*ret_devnr = devnr;
@@ -1326,6 +1340,9 @@ int vt_restore(int fd) {
};
int r, q = 0;
if (isatty(fd) < 1)
return log_debug_errno(errno, "Asked to restore the VT for an fd that does not refer to a terminal: %m");
if (ioctl(fd, KDSETMODE, KD_TEXT) < 0)
q = log_debug_errno(errno, "Failed to set VT in text mode, ignoring: %m");
@@ -1359,6 +1376,9 @@ int vt_release(int fd, bool restore) {
* sent by the kernel and optionally reset the VT in text and auto
* VT-switching modes. */
if (isatty(fd) < 1)
return log_debug_errno(errno, "Asked to release the VT for an fd that does not refer to a terminal: %m");
if (ioctl(fd, VT_RELDISP, 1) < 0)
return -errno;