[PATCH] Re-implement auditd main loop using libev

Hi! This is my first post here, so be gentle... :-) This is the first in a (hopefully short) series of patches to add the server side of the remote logging that was started in the 1.7 series. The idea here is to use the libev event library to manage events coming in to auditd, be they from netlink, signals, or some network connection (a future patch); rather than the custom event loop that only supported netlink. This also simplifies signal handling, as signals are recognized synchronously in the main context instead of in a signal context. Comments? DJ Proposed ChangeLog entry: - Reimplement auditd main loop using libev (DJ Delorie) diff -x .svn -urpN pristine/src/auditd.c trunk/src/auditd.c --- pristine/src/auditd.c 2008-08-07 15:54:51.000000000 -0400 +++ trunk/src/auditd.c 2008-08-07 19:27:35.000000000 -0400 @@ -45,6 +45,10 @@ #include "auditd-dispatch.h" #include "private.h" +#include "ev.h" + +#define EV_STOP() ev_unloop (ev_default_loop (EVFLAG_AUTO), EVUNLOOP_ALL), stop = 1; + #define DEFAULT_BUF_SZ 448 #define DMSG_SIZE (DEFAULT_BUF_SZ + 48) #define SUCCESS 0 @@ -52,9 +56,6 @@ /* Global Data */ volatile int stop = 0; -volatile int hup = 0; -volatile int rot = 0; -volatile int resume = 0; /* Local data */ static int fd = -1; @@ -62,6 +63,8 @@ static struct daemon_conf config; static const char *pidfile = "/var/run/auditd.pid"; static int init_pipe[2]; static int do_fork = 1; +static struct auditd_reply_list *rep = NULL; +static int hup_info_requested = 0, usr1_info_requested = 0; /* Local function prototypes */ static void close_down(void); @@ -88,9 +91,9 @@ static void usage(void) /* * SIGTERM handler */ -static void term_handler( int sig ) +static void term_handler( struct ev_loop *loop, struct ev_signal *sig, int revents ) { - stop = 1; + EV_STOP (); } /* @@ -104,31 +107,47 @@ static void thread_killer( int sig ) /* * Used with sigalrm to force exit */ -static void hup_handler( int sig ) +static void hup_handler( struct ev_loop *loop, struct ev_signal *sig, int revents ) { - hup = 1; + int rc; + + rc = audit_request_signal_info(fd); + if (rc < 0) + send_audit_event(AUDIT_DAEMON_CONFIG, + "auditd error getting hup info - no change, sending auid=? pid=? subj=? res=failed"); + else + hup_info_requested = 1; } /* * Used to force log rotation */ -static void user1_handler( int sig ) +static void user1_handler( struct ev_loop *loop, struct ev_signal *sig, int revents ) { - rot = 1; + int rc; + + rc = audit_request_signal_info(fd); + if (rc < 0) + send_audit_event(AUDIT_DAEMON_ROTATE, + "auditd error getting usr1 info - no change, sending auid=? pid=? subj=? res=failed"); + else + usr1_info_requested = 1; } /* * Used to resume logging */ -static void user2_handler( int sig ) +static void user2_handler( struct ev_loop *loop, struct ev_signal *sig, int revents ) { - resume = 1; + resume_logging(); + send_audit_event(AUDIT_DAEMON_RESUME, + "auditd resuming logging, sending auid=? pid=? subj=? res=success"); } /* * Used with email alerts to cleanup */ -static void child_handler( int sig ) +static void child_handler( struct ev_loop *loop, struct ev_signal *sig, int revents ) { while (waitpid(-1, NULL, WNOHANG) > 0) ; /* empty */ @@ -323,19 +342,100 @@ static void tell_parent(int status) } while (rc < 0 && errno == EINTR); } +static void netlink_handler( struct ev_loop *loop, struct ev_io *io, int revents ) +{ + if (rep == NULL) { + if ((rep = malloc(sizeof(*rep))) == NULL) { + char emsg[DEFAULT_BUF_SZ]; + snprintf(emsg, sizeof(emsg), + "auditd error halt, auid=%u pid=%d res=failed", + audit_getloginuid(), getpid()); + EV_STOP (); + //FIXME add subj + send_audit_event(AUDIT_DAEMON_ABORT, emsg); + audit_msg(LOG_ERR, + "Cannot allocate audit reply, exiting"); + close_down(); + if (pidfile) + unlink(pidfile); + shutdown_dispatcher(); + return; + } + } + if (audit_get_reply(fd, &rep->reply, + GET_REPLY_NONBLOCKING, 0) > 0) { + switch (rep->reply.type) + { /* For now dont process these */ + case NLMSG_NOOP: + case NLMSG_DONE: + case NLMSG_ERROR: + case AUDIT_GET: /* Or these */ + case AUDIT_LIST: + case AUDIT_LIST_RULES: + case AUDIT_FIRST_DAEMON...AUDIT_LAST_DAEMON: + break; + case AUDIT_SIGNAL_INFO: + if (hup_info_requested) { + audit_msg(LOG_DEBUG, + "HUP detected, starting config manager"); + if (start_config_manager(rep)) { + send_audit_event( + AUDIT_DAEMON_CONFIG, + "auditd error getting hup info - no change," + " sending auid=? pid=? subj=? res=failed"); + } + rep = NULL; + hup_info_requested = 0; + } else if(usr1_info_requested){ + char usr1[MAX_AUDIT_MESSAGE_LENGTH]; + if (rep->reply.len == 24) { + snprintf(usr1, + sizeof(usr1), + "auditd sending auid=? pid=? subj=?"); + } else { + snprintf(usr1, + sizeof(usr1), + "auditd sending auid=%u pid=%d subj=%s", + rep->reply.signal_info->uid, + rep->reply.signal_info->pid, + rep->reply.signal_info->ctx); + } + send_audit_event( + AUDIT_DAEMON_ROTATE, + usr1); + } + break; + default: + distribute_event(rep); + rep = NULL; + break; + } + } else { + if (errno == EFBIG) { + // FIXME do err action + } + } +} + int main(int argc, char *argv[]) { struct sigaction sa; fd_set read_mask; - struct auditd_reply_list *rep = NULL; struct rlimit limit; - int hup_info_requested = 0, usr1_info_requested = 0; int i; int opt_foreground = 0, opt_allow_links = 0; enum startup_state opt_startup = startup_enable; int c; extern char *optarg; extern int optind; + struct ev_loop *loop; + struct ev_io netlink_watcher; + struct ev_signal sigterm_watcher; + struct ev_signal sighup_watcher; + struct ev_signal sigusr1_watcher; + struct ev_signal sigusr2_watcher; + struct ev_signal sigchld_watcher; + int rc; /* Get params && set mode */ while ((c = getopt(argc, argv, "flns:")) != -1) { @@ -400,17 +500,6 @@ int main(int argc, char *argv[]) sa.sa_handler = SIG_IGN; for (i=1; i<NSIG; i++) sigaction( i, &sa, NULL ); - /* Set handler for the ones we care about */ - sa.sa_handler = term_handler; - sigaction( SIGTERM, &sa, NULL ); - sa.sa_handler = hup_handler; - sigaction( SIGHUP, &sa, NULL ); - sa.sa_handler = user1_handler; - sigaction( SIGUSR1, &sa, NULL ); - sa.sa_handler = user2_handler; - sigaction( SIGUSR2, &sa, NULL ); - sa.sa_handler = child_handler; - sigaction( SIGCHLD, &sa, NULL ); atexit(clean_exit); @@ -561,147 +650,50 @@ int main(int argc, char *argv[]) if (do_fork) close(init_pipe[1]); - for (;;) { - struct timeval tv; - int retval; - - if (rep == NULL) { - if ((rep = malloc(sizeof(*rep))) == NULL) { - char emsg[DEFAULT_BUF_SZ]; - snprintf(emsg, sizeof(emsg), - "auditd error halt, auid=%u pid=%d res=failed", - audit_getloginuid(), getpid()); - stop = 1; -//FIXME add subj - send_audit_event(AUDIT_DAEMON_ABORT, emsg); - audit_msg(LOG_ERR, - "Cannot allocate audit reply, exiting"); - close_down(); - if (pidfile) - unlink(pidfile); - shutdown_dispatcher(); - return 1; - } - } - - /* This will pause for 30 seconds */ - do { - tv.tv_sec = 30; - tv.tv_usec = 0; - FD_ZERO(&read_mask); - FD_SET(fd, &read_mask); - retval = select(fd+1, &read_mask, NULL, NULL, &tv); - } while (retval == -1 && errno == EINTR && - !stop && !hup && !rot && !resume); - - if (!stop && !hup && !rot && !resume && retval > 0) { - if (audit_get_reply(fd, &rep->reply, - GET_REPLY_NONBLOCKING, 0) > 0) { - switch (rep->reply.type) - { /* For now dont process these */ - case NLMSG_NOOP: - case NLMSG_DONE: - case NLMSG_ERROR: - case AUDIT_GET: /* Or these */ - case AUDIT_LIST: - case AUDIT_LIST_RULES: - case AUDIT_FIRST_DAEMON...AUDIT_LAST_DAEMON: - break; - case AUDIT_SIGNAL_INFO: - if (hup_info_requested) { - audit_msg(LOG_DEBUG, - "HUP detected, starting config manager"); - if (start_config_manager(rep)) { - send_audit_event( - AUDIT_DAEMON_CONFIG, - "auditd error getting hup info - no change," - " sending auid=? pid=? subj=? res=failed"); - } - rep = NULL; - hup_info_requested = 0; - } else if(usr1_info_requested){ - char usr1[MAX_AUDIT_MESSAGE_LENGTH]; - if (rep->reply.len == 24) { - snprintf(usr1, - sizeof(usr1), - "auditd sending auid=? pid=? subj=?"); - } else { - snprintf(usr1, - sizeof(usr1), - "auditd sending auid=%u pid=%d subj=%s", - rep->reply.signal_info->uid, - rep->reply.signal_info->pid, - rep->reply.signal_info->ctx); - } - send_audit_event( - AUDIT_DAEMON_ROTATE, - usr1); - } - break; - default: - distribute_event(rep); - rep = NULL; - break; - } - } else { - if (errno == EFBIG) { - // FIXME do err action - } - } - } - if (hup) { - int rc; - hup = 0; - rc = audit_request_signal_info(fd); - if (rc < 0) - send_audit_event(AUDIT_DAEMON_CONFIG, - "auditd error getting hup info - no change, sending auid=? pid=? subj=? res=failed"); - else - hup_info_requested = 1; - } - if (rot) { - int rc; - rot = 0; - rc = audit_request_signal_info(fd); - if (rc < 0) - send_audit_event(AUDIT_DAEMON_ROTATE, - "auditd error getting usr1 info - no change, sending auid=? pid=? subj=? res=failed"); - else - usr1_info_requested = 1; - } - if (resume) { - resume = 0; - resume_logging(); - send_audit_event(AUDIT_DAEMON_RESUME, - "auditd resuming logging, sending auid=? pid=? subj=? res=success"); - } - if (stop) { - /* Write message to log that we are going down */ - int rc; - - rc = audit_request_signal_info(fd); - if (rc > 0) { - struct audit_reply trep; - - rc = get_reply(fd, &trep, rc); - if (rc > 0) { - char txt[MAX_AUDIT_MESSAGE_LENGTH]; - snprintf(txt, sizeof(txt), - "auditd normal halt, sending auid=%u pid=%d subj=%s res=success", - trep.signal_info->uid, - trep.signal_info->pid, - trep.signal_info->ctx); - send_audit_event(AUDIT_DAEMON_END, txt); - } - } - if (rc <= 0) - send_audit_event(AUDIT_DAEMON_END, - "auditd normal halt, sending auid=? pid=? subj=? res=success"); - free(rep); - shutdown_dispatcher(); - break; - } - } + loop = ev_default_loop (EVFLAG_NOENV); + + ev_io_init (&netlink_watcher, netlink_handler, fd, EV_READ); + ev_io_start (loop, &netlink_watcher); + + ev_signal_init (&sigterm_watcher, term_handler, SIGTERM); + ev_signal_start (loop, &sigterm_watcher); + + ev_signal_init (&sighup_watcher, hup_handler, SIGHUP); + ev_signal_start (loop, &sighup_watcher); + + ev_signal_init (&sigusr1_watcher, user1_handler, SIGUSR1); + ev_signal_start (loop, &sigusr1_watcher); + + ev_signal_init (&sigusr2_watcher, user2_handler, SIGUSR2); + ev_signal_start (loop, &sigusr2_watcher); + + ev_signal_init (&sigchld_watcher, child_handler, SIGCHLD); + ev_signal_start (loop, &sigchld_watcher); + + ev_loop (loop, 0); + + /* Write message to log that we are going down */ + + rc = audit_request_signal_info(fd); + if (rc > 0) { + struct audit_reply trep; + + rc = get_reply(fd, &trep, rc); + if (rc > 0) { + char txt[MAX_AUDIT_MESSAGE_LENGTH]; + snprintf(txt, sizeof(txt), + "auditd normal halt, sending auid=%u pid=%d subj=%s res=success", + trep.signal_info->uid, + trep.signal_info->pid, + trep.signal_info->ctx); + send_audit_event(AUDIT_DAEMON_END, txt); + } + } + if (rc <= 0) + send_audit_event(AUDIT_DAEMON_END, + "auditd normal halt, sending auid=? pid=? subj=? res=success"); + free(rep); + shutdown_dispatcher(); close_down(); free_config(&config);