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Start commands in the background when I/O logging is enabled. We

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can't do this on Mac OS X due to a kernel bug in tc[gs]etattr(2)
which returns EINTR on signal instead of restarting automatically.
This commit is contained in:
Todd C. Miller
2012-09-25 13:49:51 -04:00
parent 616d713e9b
commit 592f6fefb0
1 changed files with 21 additions and 5 deletions
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26
src/exec_pty.c
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@@ -1,5 +1,5 @@
/* /*
* Copyright (c) 2009-2011 Todd C. Miller <Todd.Miller@courtesan.com> * Copyright (c) 2009-2012 Todd C. Miller <Todd.Miller@courtesan.com>
* *
* Permission to use, copy, modify, and distribute this software for any * Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above * purpose with or without fee is hereby granted, provided that the above
@@ -79,6 +79,18 @@
# define winsize ttysize # define winsize ttysize
#endif #endif
/*
* Mac OS X has a bug wrt tc[gs]etpgrp where it returns EINTR if interrupted
* by a signal (usually SIGTTOU or SIGTTIN) instead of being restarted
* automatically (via ERESTART in the kernel). On other systems we can start
* the command in the background which prevents sudo from stealing /dev/tty
* input when it doesn't need to. When the command receives SIGTTOU or SIGTTIN,
* sudo will continue it in the foreground (assuming sudo is in the foreground).
*/
#ifdef __APPLE__
# define TCSETATTR_NO_RESTART
#endif
struct io_buffer { struct io_buffer {
struct io_buffer *next; struct io_buffer *next;
int len; /* buffer length (how much produced) */ int len; /* buffer length (how much produced) */
@@ -659,6 +671,7 @@ fork_pty(struct command_details *details, int sv[], int *maxfd, sigset_t *omask)
sync_ttysize(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]); sync_ttysize(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]);
} }
#ifdef TCSETATTR_NO_RESTART
/* Start out in raw mode if we are not part of a pipeline. */ /* Start out in raw mode if we are not part of a pipeline. */
if (!pipeline) { if (!pipeline) {
ttymode = TERM_RAW; ttymode = TERM_RAW;
@@ -668,6 +681,7 @@ fork_pty(struct command_details *details, int sv[], int *maxfd, sigset_t *omask)
if (!n) if (!n)
error(1, _("unable to set terminal to raw mode")); error(1, _("unable to set terminal to raw mode"));
} }
#endif
} }
/* /*
@@ -1089,17 +1103,17 @@ exec_monitor(struct command_details *details, int backchannel)
if (io_fds[SFD_STDERR] != io_fds[SFD_SLAVE]) if (io_fds[SFD_STDERR] != io_fds[SFD_SLAVE])
close(io_fds[SFD_STDERR]); close(io_fds[SFD_STDERR]);
/* /* Put command in its own process group. */
* Put command in its own process group. If we are starting the command
* in the foreground, assign its pgrp to the tty.
*/
cmnd_pgrp = cmnd_pid; cmnd_pgrp = cmnd_pid;
setpgid(cmnd_pid, cmnd_pgrp); setpgid(cmnd_pid, cmnd_pgrp);
#ifdef TCSETATTR_NO_RESTART
/* Make the command the foreground process for the pty slave. */
if (foreground) { if (foreground) {
do { do {
n = tcsetpgrp(io_fds[SFD_SLAVE], cmnd_pgrp); n = tcsetpgrp(io_fds[SFD_SLAVE], cmnd_pgrp);
} while (n == -1 && errno == EINTR); } while (n == -1 && errno == EINTR);
} }
#endif
/* Wait for errno on pipe, signal on backchannel or for SIGCHLD */ /* Wait for errno on pipe, signal on backchannel or for SIGCHLD */
maxfd = MAX(MAX(errpipe[0], signal_pipe[0]), backchannel); maxfd = MAX(MAX(errpipe[0], signal_pipe[0]), backchannel);
@@ -1289,11 +1303,13 @@ exec_pty(struct command_details *details, int *errfd)
dup2(io_fds[SFD_STDERR], STDERR_FILENO) == -1) dup2(io_fds[SFD_STDERR], STDERR_FILENO) == -1)
error(1, "dup2"); error(1, "dup2");
#ifdef TCSETATTR_NO_RESTART
/* Wait for parent to grant us the tty if we are foreground. */ /* Wait for parent to grant us the tty if we are foreground. */
if (foreground) { if (foreground) {
while (tcgetpgrp(io_fds[SFD_SLAVE]) != self) while (tcgetpgrp(io_fds[SFD_SLAVE]) != self)
; /* spin */ ; /* spin */
} }
#endif
/* We have guaranteed that the slave fd is > 2 */ /* We have guaranteed that the slave fd is > 2 */
if (io_fds[SFD_SLAVE] != -1) if (io_fds[SFD_SLAVE] != -1)