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-rw-r--r--debian/patches/upstream/PATCH-1-2-lib-pty-Put-master-PTY-into-non-blocking-mode-a.patch269
1 files changed, 269 insertions, 0 deletions
diff --git a/debian/patches/upstream/PATCH-1-2-lib-pty-Put-master-PTY-into-non-blocking-mode-a.patch b/debian/patches/upstream/PATCH-1-2-lib-pty-Put-master-PTY-into-non-blocking-mode-a.patch
new file mode 100644
index 0000000..341e29b
--- /dev/null
+++ b/debian/patches/upstream/PATCH-1-2-lib-pty-Put-master-PTY-into-non-blocking-mode-a.patch
@@ -0,0 +1,269 @@
+From: =?utf-8?b?0L3QsNCx?= <nabijaczleweli@nabijaczleweli.xyz>
+Date: Tue, 12 Apr 2022 16:25:14 +0200
+Subject: [PATCH 1/2] lib/pty: Put master PTY into non-blocking mode and
+ buffer its output to avoid deadlock
+
+If we filled the script->child buffer before the child had a chance to read any
+input, we'd sleep forever in write_all(pty->master), and the child would sleep
+forever in write(1<pty->slave>)
+
+By putting the master PTY in non-blocking mode, we can poll(pty->master,
+POLLOUT) and keep supplying more data as the child reads from the buffer
+
+Fixes Debian bug #1003095
+
+Signed-off-by: Karel Zak <kzak@redhat.com>
+---
+ include/pty-session.h | 7 +++
+ lib/pty-session.c | 126 +++++++++++++++++++++++++++++++++++++++++---------
+ 2 files changed, 110 insertions(+), 23 deletions(-)
+
+diff --git a/include/pty-session.h b/include/pty-session.h
+index 09eff43..7176d6b 100644
+--- a/include/pty-session.h
++++ b/include/pty-session.h
+@@ -81,6 +81,13 @@ struct ul_pty {
+
+ struct timeval next_callback_time;
+
++ struct ul_pty_child_buffer {
++ struct ul_pty_child_buffer *next;
++ char buf[BUFSIZ];
++ size_t size, cursor;
++ unsigned int final_input:1; /* drain child before writing */
++ } *child_buffer_head, *child_buffer_tail, *free_buffers;
++
+ unsigned int isterm:1, /* is stdin terminal? */
+ slave_echo:1; /* keep ECHO on pty slave */
+ };
+diff --git a/lib/pty-session.c b/lib/pty-session.c
+index 6f038e1..880f08d 100644
+--- a/lib/pty-session.c
++++ b/lib/pty-session.c
+@@ -69,6 +69,15 @@ struct ul_pty *ul_new_pty(int is_stdin_tty)
+
+ void ul_free_pty(struct ul_pty *pty)
+ {
++ struct ul_pty_child_buffer *hd;
++ while((hd = pty->child_buffer_head)) {
++ pty->child_buffer_head = hd->next;
++ free(hd);
++ }
++ while((hd = pty->free_buffers)) {
++ pty->free_buffers = hd->next;
++ free(hd);
++ }
+ free(pty);
+ }
+
+@@ -182,7 +191,7 @@ int ul_pty_setup(struct ul_pty *pty)
+ cfmakeraw(&attrs);
+ tcsetattr(STDIN_FILENO, TCSANOW, &attrs);
+ } else {
+- DBG(SETUP, ul_debugobj(pty, "create for non-terminal"));
++ DBG(SETUP, ul_debugobj(pty, "create for non-terminal"));
+
+ rc = openpty(&pty->master, &pty->slave, NULL, NULL, NULL);
+ if (rc)
+@@ -198,6 +207,8 @@ int ul_pty_setup(struct ul_pty *pty)
+ tcsetattr(pty->slave, TCSANOW, &attrs);
+ }
+
++ fcntl(pty->master, F_SETFL, O_NONBLOCK);
++
+ sigfillset(&ourset);
+ if (sigprocmask(SIG_BLOCK, &ourset, NULL)) {
+ rc = -errno;
+@@ -290,9 +301,27 @@ static int write_output(char *obuf, ssize_t bytes)
+ return 0;
+ }
+
+-static int write_to_child(struct ul_pty *pty, char *buf, size_t bufsz)
++static int schedule_child_write(struct ul_pty *pty, char *buf, size_t bufsz, int final)
+ {
+- return write_all(pty->master, buf, bufsz);
++ struct ul_pty_child_buffer *stash;
++ if (pty->free_buffers) {
++ stash = pty->free_buffers;
++ pty->free_buffers = stash->next;
++ memset(stash, 0, sizeof(*stash));
++ } else
++ stash = calloc(1, sizeof(*stash));
++ if (!stash)
++ return -1;
++
++ memcpy(stash->buf, buf, bufsz);
++ stash->size = bufsz;
++ stash->final_input = final ? 1 : 0;
++
++ if (pty->child_buffer_head)
++ pty->child_buffer_tail = pty->child_buffer_tail->next = stash;
++ else
++ pty->child_buffer_head = pty->child_buffer_tail = stash;
++ return 0;
+ }
+
+ /*
+@@ -311,16 +340,13 @@ static int write_to_child(struct ul_pty *pty, char *buf, size_t bufsz)
+ * maintains master+slave tty stuff within the session. Use pipe to write to
+ * pty and assume non-interactive (tee-like) behavior is NOT well supported.
+ */
+-void ul_pty_write_eof_to_child(struct ul_pty *pty)
++static void drain_child_buffers(struct ul_pty *pty)
+ {
+ unsigned int tries = 0;
+- struct pollfd fds[] = {
+- { .fd = pty->slave, .events = POLLIN }
+- };
+- char c = DEF_EOF;
++ struct pollfd fd = { .fd = pty->slave, .events = POLLIN };
+
+ DBG(IO, ul_debugobj(pty, " waiting for empty slave"));
+- while (poll(fds, 1, 10) == 1 && tries < 8) {
++ while (poll(&fd, 1, 10) == 1 && tries < 8) {
+ DBG(IO, ul_debugobj(pty, " slave is not empty"));
+ xusleep(250000);
+ tries++;
+@@ -329,7 +355,53 @@ void ul_pty_write_eof_to_child(struct ul_pty *pty)
+ DBG(IO, ul_debugobj(pty, " slave is empty now"));
+
+ DBG(IO, ul_debugobj(pty, " sending EOF to master"));
+- write_to_child(pty, &c, sizeof(char));
++}
++
++static int flush_child_buffers(struct ul_pty *pty, int *anything)
++{
++ int ret = 0, any = 0;
++ while (pty->child_buffer_head) {
++ struct ul_pty_child_buffer *hd = pty->child_buffer_head;
++
++ if(hd->final_input)
++ drain_child_buffers(pty);
++
++ DBG(IO, ul_debugobj(hd, " stdin --> master trying %zu bytes", hd->size - hd->cursor));
++ ssize_t ret = write(pty->master, hd->buf + hd->cursor, hd->size - hd->cursor);
++ if (ret == -1) {
++ DBG(IO, ul_debugobj(hd, " EAGAIN"));
++ if (!(errno == EINTR || errno == EAGAIN))
++ ret = -errno;
++ goto out;
++ }
++ DBG(IO, ul_debugobj(hd, " wrote %zd", ret));
++ any = 1;
++ hd->cursor += ret;
++ if (hd->cursor == hd->size) {
++ pty->child_buffer_head = hd->next;
++ if(!hd->next)
++ pty->child_buffer_tail = NULL;
++
++ hd->next = pty->free_buffers;
++ pty->free_buffers = hd;
++ }
++ }
++
++out:
++ /* without sync write_output() will write both input &
++ * shell output that looks like double echoing */
++ if (any)
++ fdatasync(pty->master);
++
++ if (anything)
++ *anything = any;
++ return ret;
++}
++
++void ul_pty_write_eof_to_child(struct ul_pty *pty)
++{
++ char c = DEF_EOF;
++ schedule_child_write(pty, &c, sizeof(char), 1);
+ }
+
+ static int mainloop_callback(struct ul_pty *pty)
+@@ -362,7 +434,7 @@ static int handle_io(struct ul_pty *pty, int fd, int *eof)
+ /* read from active FD */
+ bytes = read(fd, buf, sizeof(buf));
+ sigprocmask(SIG_BLOCK, &set, NULL);
+- if (bytes < 0) {
++ if (bytes == -1) {
+ if (errno == EAGAIN || errno == EINTR)
+ return 0;
+ return -errno;
+@@ -375,15 +447,11 @@ static int handle_io(struct ul_pty *pty, int fd, int *eof)
+
+ /* from stdin (user) to command */
+ if (fd == STDIN_FILENO) {
+- DBG(IO, ul_debugobj(pty, " stdin --> master %zd bytes", bytes));
++ DBG(IO, ul_debugobj(pty, " stdin --> master %zd bytes queued", bytes));
+
+- if (write_to_child(pty, buf, bytes))
++ if (schedule_child_write(pty, buf, bytes, 0))
+ return -errno;
+
+- /* without sync write_output() will write both input &
+- * shell output that looks like double echoing */
+- fdatasync(pty->master);
+-
+ /* from command (master) to stdout */
+ } else if (fd == pty->master) {
+ DBG(IO, ul_debugobj(pty, " master --> stdout %zd bytes", bytes));
+@@ -567,6 +635,11 @@ int ul_pty_proxy_master(struct ul_pty *pty)
+ } else
+ timeout = pty->poll_timeout;
+
++ if (pty->child_buffer_head)
++ pfd[POLLFD_MASTER].events |= POLLOUT;
++ else
++ pfd[POLLFD_MASTER].events &= ~POLLOUT;
++
+ /* wait for input, signal or timeout */
+ DBG(IO, ul_debugobj(pty, "calling poll() [timeout=%dms]", timeout));
+ ret = poll(pfd, ARRAY_SIZE(pfd), timeout);
+@@ -600,23 +673,30 @@ int ul_pty_proxy_master(struct ul_pty *pty)
+ if (pfd[i].revents == 0)
+ continue;
+
+- DBG(IO, ul_debugobj(pty, " active pfd[%s].fd=%d %s %s %s %s",
++ DBG(IO, ul_debugobj(pty, " active pfd[%s].fd=%d %s %s %s %s %s",
+ i == POLLFD_STDIN ? "stdin" :
+ i == POLLFD_MASTER ? "master" :
+ i == POLLFD_SIGNAL ? "signal" : "???",
+ pfd[i].fd,
+ pfd[i].revents & POLLIN ? "POLLIN" : "",
++ pfd[i].revents & POLLOUT ? "POLLOUT" : "",
+ pfd[i].revents & POLLHUP ? "POLLHUP" : "",
+ pfd[i].revents & POLLERR ? "POLLERR" : "",
+ pfd[i].revents & POLLNVAL ? "POLLNVAL" : ""));
+
+ if (i == POLLFD_SIGNAL)
+ rc = handle_signal(pty, pfd[i].fd);
+- else if (pfd[i].revents & POLLIN)
+- rc = handle_io(pty, pfd[i].fd, &eof); /* data */
++ else {
++ if (pfd[i].revents & POLLIN)
++ rc = handle_io(pty, pfd[i].fd, &eof); /* data */
++ if (pfd[i].revents & POLLOUT) /* i == POLLFD_MASTER */
++ rc = flush_child_buffers(pty, NULL);
++ }
+
+ if (rc) {
+ ul_pty_write_eof_to_child(pty);
++ for (int anything = 1; anything;)
++ flush_child_buffers(pty, &anything);
+ break;
+ }
+
+@@ -631,11 +711,11 @@ int ul_pty_proxy_master(struct ul_pty *pty)
+ */
+ if ((pfd[i].revents & POLLHUP) || (pfd[i].revents & POLLNVAL) || eof) {
+ DBG(IO, ul_debugobj(pty, " ignore FD"));
+- pfd[i].fd = -1;
+ if (i == POLLFD_STDIN) {
++ pfd[i].fd = -1;
+ ul_pty_write_eof_to_child(pty);
+- DBG(IO, ul_debugobj(pty, " ignore STDIN"));
+- }
++ } else /* i == POLLFD_MASTER */
++ pfd[i].revents &= ~POLLIN;
+ }
+ }
+ if (rc)
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-21 15:25:59 +0000