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4f8d27f29

Denis Vlasenko

2007-02-03

FAILED Duration: 12s

Subject

svlogd: do not set O_NONBLOCK on stdin permanently - that can affect other processes!

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

runit/svlogd.c +44 -28

runit/svlogd.c+44 -28

@@ -44,15 +44,19 @@ static int wstat;
	static struct taia trotate;

	static char *line;
-	static unsigned exitasap;
-	static unsigned rotateasap;
-	static unsigned reopenasap;
-	static unsigned linecomplete = 1;
-	static unsigned tmaxflag;
-	static iopause_fd input;
+	static smallint exitasap;
+	static smallint rotateasap;
+	static smallint reopenasap;
+	static smallint linecomplete = 1;
+
+	static smallint tmaxflag;

-	static const char *replace = "";
	static char repl;
+	static const char *replace = "";
+
+	sigset_t blocked_sigset;
+	static iopause_fd input;
+	static int fl_flag_0;

	static struct logdir {
	//// char *btmp;
@@ -333,7 +337,7 @@ static int buffer_pwrite(int n, char *s, unsigned len)
	if (len > (ld->sizemax - ld->size))
	len = ld->sizemax - ld->size;
	}
-	while ((i = write(ld->fdcur, s, len)) == -1) {
+	while ((i = full_write(ld->fdcur, s, len)) == -1) {
	if ((errno == ENOSPC) && (ld->nmin < ld->nmax)) {
	DIR *d;
	struct dirent *f;
@@ -585,6 +589,17 @@ static void logdirs_reopen(void)
	if (!ok) fatalx("no functional log directories");
	}

+	/* Will look good in libbb one day */
+	static ssize_t ndelay_read(int fd, void *buf, size_t count)
+	{
+	if (!(fl_flag_0 & O_NONBLOCK))
+	fcntl(fd, F_SETFL, fl_flag_0 \| O_NONBLOCK);
+	count = safe_read(fd, buf, count);
+	if (!(fl_flag_0 & O_NONBLOCK))
+	fcntl(fd, F_SETFL, fl_flag_0);
+	return count;
+	}
+
	/* Used for reading stdin */
	static int buffer_pread(int fd, char *s, unsigned len)
	{
@@ -617,17 +632,10 @@ static int buffer_pread(int fd, char *s, unsigned len)
	}

	while (1) {
-	/* Comment? */
-	sig_unblock(SIGTERM);
-	sig_unblock(SIGCHLD);
-	sig_unblock(SIGALRM);
-	sig_unblock(SIGHUP);
+	sigprocmask(SIG_UNBLOCK, &blocked_sigset, NULL);
	iopause(&input, 1, &trotate, &now);
-	sig_block(SIGTERM);
-	sig_block(SIGCHLD);
-	sig_block(SIGALRM);
-	sig_block(SIGHUP);
-	i = safe_read(fd, s, len);
+	sigprocmask(SIG_BLOCK, &blocked_sigset, NULL);
+	i = ndelay_read(fd, s, len);
	if (i >= 0) break;
	if (errno != EAGAIN) {
	warn("cannot read standard input");
@@ -775,14 +783,17 @@ int svlogd_main(int argc, char **argv)
	fndir = argv;
	input.fd = 0;
	input.events = IOPAUSE_READ;
-	/* I be damned. Linux 2.6.18: this somehow affects
-	* OTHER processes! Konsole starts to redraw itself much slower!
-	* This persists even after svlogd exits */
-	ndelay_on(input.fd);
-	sig_block(SIGTERM);
-	sig_block(SIGCHLD);
-	sig_block(SIGALRM);
-	sig_block(SIGHUP);
+	/* We cannot set NONBLOCK on fd #0 permanently - this setting
+	* _isn't_ per-process! It is shared among all other processes
+	* with the same stdin */
+	fl_flag_0 = fcntl(0, F_GETFL, 0);
+
+	sigemptyset(&blocked_sigset);
+	sigaddset(&blocked_sigset, SIGTERM);
+	sigaddset(&blocked_sigset, SIGCHLD);
+	sigaddset(&blocked_sigset, SIGALRM);
+	sigaddset(&blocked_sigset, SIGHUP);
+	sigprocmask(SIG_BLOCK, &blocked_sigset, NULL);
	sig_catch(SIGTERM, sig_term_handler);
	sig_catch(SIGCHLD, sig_child_handler);
	sig_catch(SIGALRM, sig_alarm_handler);
@@ -850,8 +861,13 @@ int svlogd_main(int argc, char **argv)
	/* linelen == no of chars incl. '\n' (or == stdin_cnt) */
	ch = lineptr[linelen-1];

-	/* write out lineptr[0..linelen-1] to each log destination */
-	/* (or lineptr[-26..linelen-1] if timestamping) */
+	/* TODO: biggest performance hit is coming from the fact
+	* that we do not buffer writes. We may read many lines
+	* in one read() above, but will do one write()
+	* per line below. Should we use stdio? */
+
+	/* write out lineptr[0..linelen-1] to each log destination
+	* (or lineptr[-26..linelen-1] if timestamping) */
	printlen = linelen;
	printptr = lineptr;
	if (timestamp) {