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-rw-r--r--src/shared/ptyfwd.c113
1 files changed, 81 insertions, 32 deletions
diff --git a/src/shared/ptyfwd.c b/src/shared/ptyfwd.c
index bb372d4001..305fd8a0f1 100644
--- a/src/shared/ptyfwd.c
+++ b/src/shared/ptyfwd.c
@@ -1,6 +1,7 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <errno.h>
+#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <stddef.h>
@@ -27,6 +28,8 @@
struct PTYForward {
sd_event *event;
+ int input_fd;
+ int output_fd;
int master;
PTYForwardFlags flags;
@@ -40,6 +43,9 @@ struct PTYForward {
struct termios saved_stdin_attr;
struct termios saved_stdout_attr;
+ bool close_input_fd:1;
+ bool close_output_fd:1;
+
bool saved_stdin:1;
bool saved_stdout:1;
@@ -73,25 +79,36 @@ struct PTYForward {
static void pty_forward_disconnect(PTYForward *f) {
- if (f) {
- f->stdin_event_source = sd_event_source_unref(f->stdin_event_source);
- f->stdout_event_source = sd_event_source_unref(f->stdout_event_source);
+ if (!f)
+ return;
+
+ f->stdin_event_source = sd_event_source_unref(f->stdin_event_source);
+ f->stdout_event_source = sd_event_source_unref(f->stdout_event_source);
- f->master_event_source = sd_event_source_unref(f->master_event_source);
- f->sigwinch_event_source = sd_event_source_unref(f->sigwinch_event_source);
- f->event = sd_event_unref(f->event);
+ f->master_event_source = sd_event_source_unref(f->master_event_source);
+ f->sigwinch_event_source = sd_event_source_unref(f->sigwinch_event_source);
+ f->event = sd_event_unref(f->event);
+ if (f->output_fd >= 0) {
if (f->saved_stdout)
- tcsetattr(STDOUT_FILENO, TCSANOW, &f->saved_stdout_attr);
+ (void) tcsetattr(f->output_fd, TCSANOW, &f->saved_stdout_attr);
+
+ /* STDIN/STDOUT should not be non-blocking normally, so let's reset it */
+ (void) fd_nonblock(f->output_fd, false);
+ if (f->close_output_fd)
+ f->output_fd = safe_close(f->output_fd);
+ }
+
+ if (f->input_fd >= 0) {
if (f->saved_stdin)
- tcsetattr(STDIN_FILENO, TCSANOW, &f->saved_stdin_attr);
+ (void) tcsetattr(f->input_fd, TCSANOW, &f->saved_stdin_attr);
- f->saved_stdout = f->saved_stdin = false;
+ (void) fd_nonblock(f->input_fd, false);
+ if (f->close_input_fd)
+ f->input_fd = safe_close(f->input_fd);
}
- /* STDIN/STDOUT should not be nonblocking normally, so let's unconditionally reset it */
- (void) fd_nonblock(STDIN_FILENO, false);
- (void) fd_nonblock(STDOUT_FILENO, false);
+ f->saved_stdout = f->saved_stdin = false;
}
static int pty_forward_done(PTYForward *f, int rcode) {
@@ -191,7 +208,7 @@ static int shovel(PTYForward *f) {
if (f->stdin_readable && f->in_buffer_full < LINE_MAX) {
- k = read(STDIN_FILENO, f->in_buffer + f->in_buffer_full, LINE_MAX - f->in_buffer_full);
+ k = read(f->input_fd, f->in_buffer + f->in_buffer_full, LINE_MAX - f->in_buffer_full);
if (k < 0) {
if (errno == EAGAIN)
@@ -275,7 +292,7 @@ static int shovel(PTYForward *f) {
if (f->stdout_writable && f->out_buffer_full > 0) {
- k = write(STDOUT_FILENO, f->out_buffer, f->out_buffer_full);
+ k = write(f->output_fd, f->out_buffer, f->out_buffer_full);
if (k < 0) {
if (errno == EAGAIN)
@@ -345,7 +362,7 @@ static int on_stdin_event(sd_event_source *e, int fd, uint32_t revents, void *us
assert(e);
assert(e == f->stdin_event_source);
assert(fd >= 0);
- assert(fd == STDIN_FILENO);
+ assert(fd == f->input_fd);
if (revents & (EPOLLIN|EPOLLHUP))
f->stdin_readable = true;
@@ -360,7 +377,7 @@ static int on_stdout_event(sd_event_source *e, int fd, uint32_t revents, void *u
assert(e);
assert(e == f->stdout_event_source);
assert(fd >= 0);
- assert(fd == STDOUT_FILENO);
+ assert(fd == f->output_fd);
if (revents & (EPOLLOUT|EPOLLHUP))
f->stdout_writable = true;
@@ -377,7 +394,7 @@ static int on_sigwinch_event(sd_event_source *e, const struct signalfd_siginfo *
assert(e == f->sigwinch_event_source);
/* The window size changed, let's forward that. */
- if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0)
+ if (ioctl(f->output_fd, TIOCGWINSZ, &ws) >= 0)
(void) ioctl(f->master, TIOCSWINSZ, &ws);
return 0;
@@ -400,6 +417,8 @@ int pty_forward_new(
*f = (struct PTYForward) {
.flags = flags,
.master = -1,
+ .input_fd = -1,
+ .output_fd = -1,
};
if (event)
@@ -410,14 +429,42 @@ int pty_forward_new(
return r;
}
- if (!(flags & PTY_FORWARD_READ_ONLY)) {
- r = fd_nonblock(STDIN_FILENO, true);
- if (r < 0)
- return r;
-
- r = fd_nonblock(STDOUT_FILENO, true);
- if (r < 0)
- return r;
+ if (FLAGS_SET(flags, PTY_FORWARD_READ_ONLY))
+ f->output_fd = STDOUT_FILENO;
+ else {
+ /* If we shall be invoked in interactive mode, let's switch on non-blocking mode, so that we
+ * never end up staving one direction while we block on the other. However, let's be careful
+ * here and not turn on O_NONBLOCK for stdin/stdout directly, but of re-opened copies of
+ * them. This has two advantages: when we are killed abruptly the stdin/stdout fds won't be
+ * left in O_NONBLOCK state for the next process using them. In addition, if some process
+ * running in the background wants to continue writing to our stdout it can do so without
+ * being confused by O_NONBLOCK. */
+
+ f->input_fd = fd_reopen(STDIN_FILENO, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
+ if (f->input_fd < 0) {
+ /* Handle failures gracefully, after all certain fd types cannot be reopened
+ * (sockets, …) */
+ log_debug_errno(f->input_fd, "Failed to reopen stdin, using original fd: %m");
+
+ r = fd_nonblock(STDIN_FILENO, true);
+ if (r < 0)
+ return r;
+
+ f->input_fd = STDIN_FILENO;
+ } else
+ f->close_input_fd = true;
+
+ f->output_fd = fd_reopen(STDOUT_FILENO, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
+ if (f->output_fd < 0) {
+ log_debug_errno(f->output_fd, "Failed to reopen stdout, using original fd: %m");
+
+ r = fd_nonblock(STDOUT_FILENO, true);
+ if (r < 0)
+ return r;
+
+ f->output_fd = STDOUT_FILENO;
+ } else
+ f->close_output_fd = true;
}
r = fd_nonblock(master, true);
@@ -426,7 +473,7 @@ int pty_forward_new(
f->master = master;
- if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) < 0) {
+ if (ioctl(f->output_fd, TIOCGWINSZ, &ws) < 0) {
/* If we can't get the resolution from the output fd, then use our internal, regular width/height,
* i.e. something derived from $COLUMNS and $LINES if set. */
@@ -439,7 +486,9 @@ int pty_forward_new(
(void) ioctl(master, TIOCSWINSZ, &ws);
if (!(flags & PTY_FORWARD_READ_ONLY)) {
- if (tcgetattr(STDIN_FILENO, &f->saved_stdin_attr) >= 0) {
+ assert(f->input_fd >= 0);
+
+ if (tcgetattr(f->input_fd, &f->saved_stdin_attr) >= 0) {
struct termios raw_stdin_attr;
f->saved_stdin = true;
@@ -447,10 +496,10 @@ int pty_forward_new(
raw_stdin_attr = f->saved_stdin_attr;
cfmakeraw(&raw_stdin_attr);
raw_stdin_attr.c_oflag = f->saved_stdin_attr.c_oflag;
- tcsetattr(STDIN_FILENO, TCSANOW, &raw_stdin_attr);
+ tcsetattr(f->input_fd, TCSANOW, &raw_stdin_attr);
}
- if (tcgetattr(STDOUT_FILENO, &f->saved_stdout_attr) >= 0) {
+ if (tcgetattr(f->output_fd, &f->saved_stdout_attr) >= 0) {
struct termios raw_stdout_attr;
f->saved_stdout = true;
@@ -459,10 +508,10 @@ int pty_forward_new(
cfmakeraw(&raw_stdout_attr);
raw_stdout_attr.c_iflag = f->saved_stdout_attr.c_iflag;
raw_stdout_attr.c_lflag = f->saved_stdout_attr.c_lflag;
- tcsetattr(STDOUT_FILENO, TCSANOW, &raw_stdout_attr);
+ tcsetattr(f->output_fd, TCSANOW, &raw_stdout_attr);
}
- r = sd_event_add_io(f->event, &f->stdin_event_source, STDIN_FILENO, EPOLLIN|EPOLLET, on_stdin_event, f);
+ r = sd_event_add_io(f->event, &f->stdin_event_source, f->input_fd, EPOLLIN|EPOLLET, on_stdin_event, f);
if (r < 0 && r != -EPERM)
return r;
@@ -470,7 +519,7 @@ int pty_forward_new(
(void) sd_event_source_set_description(f->stdin_event_source, "ptyfwd-stdin");
}
- r = sd_event_add_io(f->event, &f->stdout_event_source, STDOUT_FILENO, EPOLLOUT|EPOLLET, on_stdout_event, f);
+ r = sd_event_add_io(f->event, &f->stdout_event_source, f->output_fd, EPOLLOUT|EPOLLET, on_stdout_event, f);
if (r == -EPERM)
/* stdout without epoll support. Likely redirected to regular file. */
f->stdout_writable = true;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-03 13:13:19 +0100