>From b7326b5b54cfa44a022ec5e894a36985bf764525 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A1draig=20Brady?= Date: Wed, 6 Jul 2011 23:17:10 +0100 Subject: [PATCH] timeout: add --foreground to support interactive commands Or more accurately, commands not started from the shell prompt, that are interactive, or need to receive Ctrl-C etc. from the terminal. * doc/coreutils.texi (timeout invocation): Document --foreground. * src/timeout.c (main): Set the foreground flag and don't create a separate group. (cleanup): Only send a signal directly to the monitored command when the foreground flag is set. (usage): Describe --foreground. NEWS: Mention the new option. Reported by Shay Shimony Analysis by Alan Curry Fix suggested by Paul Eggert --- NEWS | 4 ++++ doc/coreutils.texi | 17 +++++++++++++++++ src/timeout.c | 36 ++++++++++++++++++++++++++++-------- 3 files changed, 49 insertions(+), 8 deletions(-) diff --git a/NEWS b/NEWS index d58df26..cde68d3 100644 --- a/NEWS +++ b/NEWS @@ -29,6 +29,10 @@ GNU coreutils NEWS -*- outline -*- Note the use of single quotes, not double quotes. That creates files named xaa.xz, xab.xz and xac.xz. + timeout accepts a new --foreground option, to support commands not started + directly from a shell prompt, where the command is interactive or needs to + receive signals initiated from the terminal. + ** Improvements shuf outputs small subsets of large permutations much more efficiently. diff --git a/doc/coreutils.texi b/doc/coreutils.texi index c59af2f..e04806d 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -15651,6 +15651,23 @@ The program accepts the following options. Also see @ref{Common options}. Options must precede operands. @table @samp address@hidden --foreground address@hidden --foreground +Don't create a separate background program group, so that +the managed @var{COMMAND} can use the foreground TTY normally. +This is needed to support timing out commands not started +directly from an interactive shell, in two situations. address@hidden address@hidden address@hidden is interactive and needs to read from the terminal for example address@hidden +the user wants to support sending signals directly to @var{command} +from the terminal (like Ctrl-C for example) address@hidden enumerate + +Note in this mode of operation, any children of @var{command} +will not be timed out. + @item -k @var{duration} @itemx address@hidden @opindex -k diff --git a/src/timeout.c b/src/timeout.c index a686225..8f0980b 100644 --- a/src/timeout.c +++ b/src/timeout.c @@ -67,11 +67,19 @@ static int term_signal = SIGTERM; /* same default as kill command. */ static int monitored_pid; static int sigs_to_ignore[NSIG]; /* so monitor can ignore sigs it resends. */ static unsigned long kill_after; +static bool foreground; /* whether to use another program group. */ + +/* for long options with no corresponding short option, use enum */ +enum +{ + FOREGROUND_OPTION = CHAR_MAX + 1 +}; static struct option const long_options[] = { {"kill-after", required_argument, NULL, 'k'}, {"signal", required_argument, NULL, 's'}, + {"foreground", no_argument, NULL, FOREGROUND_OPTION}, {GETOPT_HELP_OPTION_DECL}, {GETOPT_VERSION_OPTION_DECL}, {NULL, 0, NULL, 0} @@ -96,6 +104,8 @@ cleanup (int sig) } if (monitored_pid) { + int where = foreground ? monitored_pid : 0; + if (sigs_to_ignore[sig]) { sigs_to_ignore[sig] = 0; @@ -108,9 +118,10 @@ cleanup (int sig) alarm (kill_after); kill_after = 0; /* Don't let later signals reset kill alarm. */ } - send_sig (0, sig); + + send_sig (where, sig); if (sig != SIGKILL && sig != SIGCONT) - send_sig (0, SIGCONT); + send_sig (where, SIGCONT); } else /* we're the child or the child is not exec'd yet. */ _exit (128 + sig); @@ -134,13 +145,17 @@ Start COMMAND, and kill it if still running after DURATION.\n\ Mandatory arguments to long options are mandatory for short options too.\n\ "), stdout); fputs (_("\ + --foreground\n\ + When not running timeout directly from a shell prompt,\n\ + allow COMMAND to read from the TTY and receive TTY signals.\n\ + In this mode, children of COMMAND will not be timed out.\n\ -k, --kill-after=DURATION\n\ - also send a KILL signal if COMMAND is still running\n\ - this long after the initial signal was sent.\n\ + also send a KILL signal if COMMAND is still running\n\ + this long after the initial signal was sent.\n\ -s, --signal=SIGNAL\n\ - specify the signal to be sent on timeout.\n\ - SIGNAL may be a name like `HUP' or a number.\n\ - See `kill -l` for a list of signals\n"), stdout); + specify the signal to be sent on timeout.\n\ + SIGNAL may be a name like `HUP' or a number.\n\ + See `kill -l` for a list of signals\n"), stdout); fputs (HELP_OPTION_DESCRIPTION, stdout); fputs (VERSION_OPTION_DESCRIPTION, stdout); @@ -266,6 +281,10 @@ main (int argc, char **argv) usage (EXIT_CANCELED); break; + case FOREGROUND_OPTION: + foreground = true; + break; + case_GETOPT_HELP_CHAR; case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); @@ -287,7 +306,8 @@ main (int argc, char **argv) Note we don't just put the child in a separate group as then we would need to worry about foreground and background groups and propagating signals between them. */ - setpgid (0, 0); + if (!foreground) + setpgid (0, 0); /* Setup handlers before fork() so that we handle any signals caused by child, without races. */ -- 1.7.5.2