Date: Tue, 28 Dec 2010 18:56:55 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org Subject: svn commit: r216768 - stable/8/usr.bin/gcore Message-ID: <201012281856.oBSIut5t073911@svn.freebsd.org>
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Author: jhb Date: Tue Dec 28 18:56:55 2010 New Revision: 216768 URL: http://svn.freebsd.org/changeset/base/216768 Log: MFC 203532: Fix gcore so that it can have the '-s' flag without hanging. Modified: stable/8/usr.bin/gcore/gcore.c Directory Properties: stable/8/usr.bin/gcore/ (props changed) Modified: stable/8/usr.bin/gcore/gcore.c ============================================================================== --- stable/8/usr.bin/gcore/gcore.c Tue Dec 28 18:37:10 2010 (r216767) +++ stable/8/usr.bin/gcore/gcore.c Tue Dec 28 18:56:55 2010 (r216768) @@ -65,7 +65,6 @@ __FBSDID("$FreeBSD$"); #include <err.h> #include <fcntl.h> -#include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -75,7 +74,6 @@ __FBSDID("$FreeBSD$"); int pflags; static void killed(int); -static void restart_target(void); static void usage(void) __dead2; static pid_t pid; @@ -152,36 +150,28 @@ main(int argc, char *argv[]) fd = open(corefile, O_RDWR|O_CREAT|O_TRUNC, DEFFILEMODE); if (fd < 0) err(1, "%s", corefile); - if ((pflags & PFLAGS_RESUME) != 0) { - signal(SIGHUP, killed); - signal(SIGINT, killed); - signal(SIGTERM, killed); - if (kill(pid, SIGSTOP) == -1) - err(1, "%d: stop signal", pid); - atexit(restart_target); - } + /* + * The semantics of the 's' flag is to stop the target process. + * Previous versions of gcore would manage this by trapping SIGHUP, + * SIGINT and SIGTERM (to be passed to the target pid), and then + * signal the child to stop. + * + * However, this messes up if the selected dumper uses ptrace calls + * that leave the child already stopped. The waitpid call in elfcore + * never returns. + * + * The best thing to do here is to externalize the 's' flag and let + * each dumper dispose of what that means, if anything. For the elfcore + * dumper, the 's' flag is a no-op since the ptrace attach stops the + * process in question already. + */ + dumper->dump(efd, fd, pid); (void)close(fd); (void)close(efd); exit(0); } -static void -killed(int sig) -{ - - restart_target(); - signal(sig, SIG_DFL); - kill(getpid(), sig); -} - -static void -restart_target(void) -{ - - kill(pid, SIGCONT); -} - void usage(void) {
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