Date: Thu, 28 Sep 2023 15:52:25 GMT From: Mark Johnston <markj@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: f804f2365081 - main - syslogd: Centralize operations into a kevent loop Message-ID: <202309281552.38SFqPKB021672@gitrepo.freebsd.org>
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The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=f804f23650815dd3a96b3ab2b24152d25c7364c3 commit f804f23650815dd3a96b3ab2b24152d25c7364c3 Author: Jake Freeland <jfree@FreeBSD.org> AuthorDate: 2023-09-01 02:49:29 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2023-09-28 15:51:52 +0000 syslogd: Centralize operations into a kevent loop Use kqueue(2) for socket I/O and signal notification. Previously, select(2) and traditional signal handlers were being used. This change centralizes all of the async notification delivery into a single loop so future Capsicum sandboxing will be easier. It also simplifies the code by removing boiler-plate cruft that comes with the older interfaces. Reviewed by: Slawa Olhovchenkov, markj, emaste MFC after: 3 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D41363 --- usr.sbin/syslogd/syslogd.c | 226 +++++++++++++++++---------------------------- 1 file changed, 86 insertions(+), 140 deletions(-) diff --git a/usr.sbin/syslogd/syslogd.c b/usr.sbin/syslogd/syslogd.c index c8420298f117..21e2d48b0c37 100644 --- a/usr.sbin/syslogd/syslogd.c +++ b/usr.sbin/syslogd/syslogd.c @@ -104,6 +104,7 @@ static char sccsid[] = "@(#)syslogd.c 8.3 (Berkeley) 4/4/94"; #define RCVBUF_MINSIZE (80 * 1024) /* minimum size of dgram rcv buffer */ #include <sys/param.h> +#include <sys/event.h> #include <sys/ioctl.h> #include <sys/mman.h> #include <sys/queue.h> @@ -371,6 +372,16 @@ static const char *TypeNames[] = { "FORW", "USERS", "WALL", "PIPE" }; +static const int sigcatch[] = { + SIGHUP, + SIGINT, + SIGQUIT, + SIGPIPE, + SIGALRM, + SIGTERM, + SIGCHLD, +}; + static bool Debug; /* debug flag */ static bool Foreground = false; /* Run in foreground, instead of daemonizing */ static bool resolve = true; /* resolve hostname */ @@ -402,13 +413,10 @@ static bool UniquePriority; /* Only log specified priority? */ static int LogFacPri; /* Put facility and priority in log message: */ /* 0=no, 1=numeric, 2=names */ static bool KeepKernFac; /* Keep remotely logged kernel facility */ -static bool needdofsync = false; /* Are any file(s) waiting to be fsynced? */ +static bool needdofsync = true; /* Are any file(s) waiting to be fsynced? */ static struct pidfh *pfh; -static int sigpipe[2]; /* Pipe to catch a signal during select(). */ static bool RFC3164OutputFormat = true; /* Use legacy format by default. */ -static volatile sig_atomic_t MarkSet, WantDie, WantInitialize, WantReapchild; - struct iovlist; static int allowaddr(char *); @@ -421,9 +429,7 @@ static int deadq_remove(struct deadq_entry *); static int deadq_removebypid(pid_t); static int decode(const char *, const CODE *); static void die(int) __dead2; -static void dodie(int); static void dofsync(void); -static void domark(int); static void fprintlog_first(struct filed *, const char *, const char *, const char *, const char *, const char *, const char *, int); static void fprintlog_write(struct filed *, struct iovlist *, int); @@ -437,8 +443,6 @@ static void markit(void); static int socksetup(struct peer *); static int socklist_recv_file(struct socklist *); static int socklist_recv_sock(struct socklist *); -static int socklist_recv_signal(struct socklist *); -static void sighandler(int); static int skip_message(const char *, const char *, int); static int evaluate_prop_filter(const struct prop_filter *filter, const char *value); @@ -526,14 +530,14 @@ addsock(struct addrinfo *ai, struct socklist *sl0) int main(int argc, char *argv[]) { - int ch, i, s, fdsrmax = 0; - bool bflag = false, pflag = false, Sflag = false; - fd_set *fdsr = NULL; - struct timeval tv, *tvp; - struct peer *pe; + sigset_t sigset = { }; + struct kevent ev; struct socklist *sl; - pid_t ppid = 1, spid; + struct peer *pe; + pid_t ppid = -1, spid; + int ch, kq, s; char *p; + bool bflag = false, pflag = false, Sflag = false; if (madvise(NULL, 0, MADV_PROTECT) != 0) dprintf("madvise() failed: %s\n", strerror(errno)); @@ -705,17 +709,6 @@ main(int argc, char *argv[]) if (RFC3164OutputFormat && MaxForwardLen > 1024) errx(1, "RFC 3164 messages may not exceed 1024 bytes"); - /* Pipe to catch a signal during select(). */ - s = pipe2(sigpipe, O_CLOEXEC); - if (s < 0) { - err(1, "cannot open a pipe for signals"); - } else { - addsock(NULL, &(struct socklist){ - .sl_socket = sigpipe[0], - .sl_recv = socklist_recv_signal - }); - } - /* Listen by default: /dev/klog. */ s = open(_PATH_KLOG, O_RDONLY | O_NONBLOCK | O_CLOEXEC, 0); if (s < 0) { @@ -767,108 +760,82 @@ main(int argc, char *argv[]) (void)strlcpy(consfile.fu_fname, ctty + sizeof _PATH_DEV - 1, sizeof(consfile.fu_fname)); (void)strlcpy(bootfile, getbootfile(), sizeof(bootfile)); - (void)signal(SIGTERM, dodie); - (void)signal(SIGINT, Debug ? dodie : SIG_IGN); - (void)signal(SIGQUIT, Debug ? dodie : SIG_IGN); - (void)signal(SIGHUP, sighandler); - (void)signal(SIGCHLD, sighandler); - (void)signal(SIGALRM, domark); - (void)signal(SIGPIPE, SIG_IGN); /* We'll catch EPIPE instead. */ + + kq = kqueue(); + if (kq == -1) { + warn("failed to initialize kqueue"); + pidfile_remove(pfh); + exit(1); + } + STAILQ_FOREACH(sl, &shead, next) { + EV_SET(&ev, sl->sl_socket, EVFILT_READ, EV_ADD, 0, 0, sl); + if (kevent(kq, &ev, 1, NULL, 0, NULL) == -1) { + warn("failed to add kevent to kqueue"); + pidfile_remove(pfh); + exit(1); + } + } + for (size_t i = 0; i < nitems(sigcatch); ++i) { + EV_SET(&ev, sigcatch[i], EVFILT_SIGNAL, EV_ADD, 0, 0, NULL); + if (kevent(kq, &ev, 1, NULL, 0, NULL) == -1) { + warn("failed to add kevent to kqueue"); + pidfile_remove(pfh); + exit(1); + } + (void)sigaddset(&sigset, sigcatch[i]); + } + if (sigprocmask(SIG_BLOCK, &sigset, NULL) != 0) { + warn("failed to apply signal mask"); + pidfile_remove(pfh); + exit(1); + } (void)alarm(TIMERINTVL); /* tuck my process id away */ pidfile_write(pfh); dprintf("off & running....\n"); - - tvp = &tv; - tv.tv_sec = tv.tv_usec = 0; - - STAILQ_FOREACH(sl, &shead, next) { - if (sl->sl_socket > fdsrmax) - fdsrmax = sl->sl_socket; - } - fdsr = (fd_set *)calloc(howmany(fdsrmax+1, NFDBITS), - sizeof(*fdsr)); - if (fdsr == NULL) - errx(1, "calloc fd_set"); - + init(false); for (;;) { - if (!Initialized) - init(0); - else if (WantInitialize) - init(WantInitialize); - if (WantReapchild) - reapchild(WantReapchild); - if (MarkSet) - markit(); - if (WantDie) { - free(fdsr); - die(WantDie); - } - - bzero(fdsr, howmany(fdsrmax+1, NFDBITS) * - sizeof(*fdsr)); - - STAILQ_FOREACH(sl, &shead, next) { - if (sl->sl_socket != -1 && sl->sl_recv != NULL) - FD_SET(sl->sl_socket, fdsr); - } - i = select(fdsrmax + 1, fdsr, NULL, NULL, - needdofsync ? &tv : tvp); - switch (i) { - case 0: + if (needdofsync) { dofsync(); - needdofsync = false; - if (tvp) { - tvp = NULL; - if (ppid != 1) - kill(ppid, SIGALRM); + if (ppid != -1) { + kill(ppid, SIGALRM); + ppid = -1; } - continue; - case -1: + } + if (kevent(kq, NULL, 0, &ev, 1, NULL) == -1) { if (errno != EINTR) - logerror("select"); + logerror("kevent"); continue; } - STAILQ_FOREACH(sl, &shead, next) { - if (FD_ISSET(sl->sl_socket, fdsr)) - (*sl->sl_recv)(sl); - } - } - free(fdsr); -} - -static int -socklist_recv_signal(struct socklist *sl __unused) -{ - ssize_t len; - int i, nsig, signo; - - if (ioctl(sigpipe[0], FIONREAD, &i) != 0) { - logerror("ioctl(FIONREAD)"); - err(1, "signal pipe read failed"); - } - nsig = i / sizeof(signo); - dprintf("# of received signals = %d\n", nsig); - for (i = 0; i < nsig; i++) { - len = read(sigpipe[0], &signo, sizeof(signo)); - if (len != sizeof(signo)) { - logerror("signal pipe read failed"); - err(1, "signal pipe read failed"); - } - dprintf("Received signal: %d from fd=%d\n", signo, - sigpipe[0]); - switch (signo) { - case SIGHUP: - WantInitialize = 1; + switch (ev.filter) { + case EVFILT_READ: + sl = ev.udata; + if (sl->sl_socket != -1 && sl->sl_recv != NULL) + sl->sl_recv(sl); break; - case SIGCHLD: - WantReapchild = 1; + case EVFILT_SIGNAL: + switch (ev.ident) { + case SIGHUP: + init(true); + break; + case SIGINT: + case SIGQUIT: + case SIGTERM: + if (ev.ident == SIGTERM || Debug) + die(ev.ident); + break; + case SIGALRM: + markit(); + break; + case SIGCHLD: + reapchild(ev.ident); + break; + } break; } } - return (0); } static int @@ -1758,6 +1725,7 @@ dofsync(void) (void)fsync(f->f_file); } } + needdofsync = false; } /* @@ -2259,7 +2227,6 @@ reapchild(int signo __unused) } } } - WantReapchild = 0; } /* @@ -2298,20 +2265,6 @@ cvthname(struct sockaddr *f) return (hname); } -static void -dodie(int signo) -{ - - WantDie = signo; -} - -static void -domark(int signo __unused) -{ - - MarkSet = 1; -} - /* * Print syslogd errors some place. */ @@ -2536,14 +2489,6 @@ readconfigfile(const char *path) } } -static void -sighandler(int signo) -{ - - /* Send an wake-up signal to the select() loop. */ - write(sigpipe[1], &signo, sizeof(signo)); -} - /* * INIT -- Initialize syslogd from configuration table */ @@ -2558,7 +2503,6 @@ init(int signo) char bootfileMsg[MAXLINE + 1]; dprintf("init\n"); - WantInitialize = 0; /* * Load hostname (may have changed). @@ -3245,7 +3189,6 @@ markit(void) dq->dq_timeout--; } } - MarkSet = 0; (void)alarm(TIMERINTVL); } @@ -3621,6 +3564,7 @@ validate(struct sockaddr *sa, const char *hname) static int p_open(const char *prog, pid_t *rpid) { + sigset_t sigset = { }; int pfd[2], nulldesc; pid_t pid; char *argv[4]; /* sh -c cmd NULL */ @@ -3650,10 +3594,12 @@ p_open(const char *prog, pid_t *rpid) alarm(0); - /* Restore signals marked as SIG_IGN. */ - (void)signal(SIGINT, SIG_DFL); - (void)signal(SIGQUIT, SIG_DFL); - (void)signal(SIGPIPE, SIG_DFL); + for (size_t i = 0; i < nitems(sigcatch); ++i) + (void)sigaddset(&sigset, sigcatch[i]); + if (sigprocmask(SIG_UNBLOCK, &sigset, NULL) != 0) { + logerror("sigprocmask"); + exit(1); + } dup2(pfd[0], STDIN_FILENO); dup2(nulldesc, STDOUT_FILENO);
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