diff options
Diffstat (limited to '')
| -rw-r--r-- | debian/patches/upstream/PATCH-1-2-lib-pty-Put-master-PTY-into-non-blocking-mode-a.patch | 269 |
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) |