bytemark/flexnbd-c
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proxy: Switch to blocking I/O with signal handlers to exit.

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It's safe to terminate the proxy at any point in its lifecycle, so
there's no point using signalfd() (and the associated select() +
non-blocking I/O gubbins) in it. We might want to use non-blocking
I/O in the future for other reasons, of course, at which point it
might become sensible to use signalfd() again. For now, this makes
us reliably responsive to TERM,INT and QUIT in a way that we weren't
previously.
This commit is contained in:
nick
2013-03-19 14:39:04 +00:00
parent 5257e93cb7
commit e994b80756
3 changed files with 76 additions and 140 deletions
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89
src/proxy-main.c
View File

@@ -1,9 +1,7 @@
#include <signal.h>
#include <sys/signalfd.h>
#include "mode.h"
#include "util.h"
#include "sockutil.h"
#include "proxy.h"
@@ -71,62 +69,38 @@ void read_proxy_param(
}
}
/* Stolen from flexnbd.c, wil change in the near future so no point DRYing */
int build_signal_fd(void)
struct proxier * proxy = NULL;
void my_exit(int signum)
{
info( "Exit signalled (%i)", signum );
if ( NULL != proxy ) {
proxy_cleanup( proxy );
};
exit( 0 );
}
int main( int argc, char *argv[] )
{
int c;
char *downstream_addr = NULL;
char *downstream_port = NULL;
char *upstream_addr = NULL;
char *upstream_port = NULL;
char *bind_addr = NULL;
int success;
sigset_t mask;
int sfd;
struct sigaction exit_action;
sigemptyset( &mask );
sigaddset( &mask, SIGTERM );
sigaddset( &mask, SIGQUIT );
sigaddset( &mask, SIGINT );
FATAL_UNLESS( 0 == pthread_sigmask( SIG_BLOCK, &mask, NULL ),
"Signal blocking failed" );
sfd = signalfd( -1, &mask, 0 );
FATAL_IF( -1 == sfd, "Failed to get a signal fd" );
return sfd;
}
struct proxier* flexnbd_create_proxying(
int signal_fd,
char* s_downstream_address,
char* s_downstream_port,
char* s_upstream_address,
char* s_upstream_port,
char* s_upstream_bind
)
{
struct proxier* proxy = proxy_create(
signal_fd,
s_downstream_address,
s_downstream_port,
s_upstream_address,
s_upstream_port,
s_upstream_bind
);
return proxy;
}
int main( int argc, char *argv[] )
{
int c;
struct proxier * proxy;
char *downstream_addr = NULL;
char *downstream_port = NULL;
char *upstream_addr = NULL;
char *upstream_port = NULL;
char *bind_addr = NULL;
int signal_fd;
int success;
signal(SIGPIPE, SIG_IGN); /* calls to splice() unhelpfully throw this */
error_init();
exit_action.sa_handler = my_exit;
exit_action.sa_mask = mask;
exit_action.sa_flags = 0;
while (1) {
c = getopt_long( argc, argv, proxy_short_options, proxy_options, NULL );
@@ -148,10 +122,7 @@ int main( int argc, char *argv[] )
exit_err( proxy_help_text );
}
signal_fd = build_signal_fd();
proxy = flexnbd_create_proxying(
signal_fd,
proxy = proxy_create(
downstream_addr,
downstream_port,
upstream_addr,
@@ -159,13 +130,19 @@ int main( int argc, char *argv[] )
bind_addr
);
/* Set these *after* proxy has been assigned to */
sigaction(SIGTERM, &exit_action, NULL);
sigaction(SIGQUIT, &exit_action, NULL);
sigaction(SIGINT, &exit_action, NULL);
signal(SIGPIPE, SIG_IGN); /* calls to splice() unhelpfully throw this */
info(
"Proxying between %s %s (downstream) and %s %s (upstream)",
downstream_addr, downstream_port, upstream_addr, upstream_port
);
success = do_proxy( proxy );
sock_try_close( signal_fd );
success = do_proxy( proxy );
proxy_destroy( proxy );
return success ? 0 : 1;
}