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authorDenis Vlasenko <vda.linux@googlemail.com>2008-06-03 14:26:12 +0000
committerDenis Vlasenko <vda.linux@googlemail.com>2008-06-03 14:26:12 +0000
commit4139fe5aec935ba3f462dcaf6aafb6e5eadf1ab9 (patch)
treecd0bc77821630182791969de1dfe24f5c19247f7
parentc28c512dce1579fdac187f78e8282635a18d0a93 (diff)
Fix bug 575 and other small problems noticed along the way.
The bug: this blocks in syslogd is stopped: #include <syslog.h> int main() { int i; for (i = 0; i < 10000; i++) syslog(LOG_INFO, "Testing, disregard...................."); return 0; } Fix: set O_NONBLOCK on fd to "/dev/log". Other fixes: do not try to write to fd -1, do not spin forever or EAGAIN, use constant sockaddr instead of recreating identical one each time, eliminate one intermediate function (SUGPIPE sig handler), use smallints where appropriate, add a few comments. Size: text data bss dec hex filename - 1140 16 21 1177 499 libc/misc/syslog/syslog.o + 1123 13 2 1138 472 libc/misc/syslog/syslog.o
-rw-r--r--libc/misc/syslog/syslog.c88
1 files changed, 46 insertions, 42 deletions
diff --git a/libc/misc/syslog/syslog.c b/libc/misc/syslog/syslog.c
index d8648b879..5bb81c282 100644
--- a/libc/misc/syslog/syslog.c
+++ b/libc/misc/syslog/syslog.c
@@ -108,25 +108,34 @@ libc_hidden_proto(vsnprintf)
__UCLIBC_MUTEX_STATIC(mylock, PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP);
-static int LogFile = -1; /* fd for log */
-static smalluint connected; /* have done connect */
-static int LogStat = 0; /* status bits, set by openlog() */
-static const char *LogTag = "syslog"; /* string to tag the entry with */
-static int LogFacility = LOG_USER; /* default facility code */
-static int LogMask = 0xff; /* mask of priorities to be logged */
-static struct sockaddr SyslogAddr; /* AF_UNIX address of local logger */
+static int LogFile = -1; /* fd for log */
+static smalluint connected; /* have done connect */
+/* all bits in option argument for openlog() fit in 8 bits */
+static smalluint LogStat = 0; /* status bits, set by openlog() */
+static const char *LogTag = "syslog"; /* string to tag the entry with */
+/* this fits in 8 bits too (LOG_LOCAL7 = 23<<3 = 184),
+ * but NB: LOG_FACMASK is bigger (= 0x03f8 = 127<<3) for some strange reason.
+ * Oh well. */
+static int LogFacility = LOG_USER;/* default facility code */
+/* bits mask of priorities (eight prios - 8 bits is enough) */
+static smalluint LogMask = 0xff; /* mask of priorities to be logged */
+/* AF_UNIX address of local logger (we use struct sockaddr
+ * instead of struct sockaddr_un since "/dev/log" is small enough) */
+static const struct sockaddr SyslogAddr = {
+ .sa_family = AF_UNIX, /* sa_family_t (usually a short) */
+ .sa_data = _PATH_LOG /* char [14] */
+};
static void
-closelog_intern(const smalluint to_default)
+closelog_intern(int sig)
{
__UCLIBC_MUTEX_LOCK(mylock);
if (LogFile != -1) {
- (void) close(LogFile);
+ (void) close(LogFile);
}
LogFile = -1;
connected = 0;
- if (to_default)
- {
+ if (sig != 0) {
LogStat = 0;
LogTag = "syslog";
LogFacility = LOG_USER;
@@ -135,12 +144,6 @@ closelog_intern(const smalluint to_default)
__UCLIBC_MUTEX_UNLOCK(mylock);
}
-static void
-sigpipe_handler (attribute_unused int sig)
-{
- closelog_intern (0);
-}
-
/*
* OPENLOG -- open system log
*/
@@ -157,22 +160,19 @@ openlog( const char *ident, int logstat, int logfac )
if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
LogFacility = logfac;
if (LogFile == -1) {
- SyslogAddr.sa_family = AF_UNIX;
- (void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
- sizeof(SyslogAddr.sa_data));
retry:
if (LogStat & LOG_NDELAY) {
if ((LogFile = socket(AF_UNIX, logType, 0)) == -1) {
goto DONE;
}
- fcntl(LogFile, F_SETFD, 1);
+ fcntl(LogFile, F_SETFD, 1); /* 1 == FD_CLOEXEC */
+ /* We don't want to block if e.g. syslogd is SIGSTOPed */
+ fcntl(LogFile, F_SETFL, O_NONBLOCK | fcntl(LogFile, F_GETFL));
}
}
if (LogFile != -1 && !connected) {
- if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr) -
- sizeof(SyslogAddr.sa_data) + strlen(SyslogAddr.sa_data)) != -1)
- {
+ if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) != -1) {
connected = 1;
} else {
if (LogFile != -1) {
@@ -208,7 +208,7 @@ vsyslog( int pri, const char *fmt, va_list ap )
int sigpipe;
memset (&action, 0, sizeof (action));
- action.sa_handler = sigpipe_handler;
+ action.sa_handler = closelog_intern;
sigemptyset (&action.sa_mask);
sigpipe = sigaction (SIGPIPE, &action, &oldaction);
@@ -255,7 +255,7 @@ vsyslog( int pri, const char *fmt, va_list ap )
__set_errno(saved_errno);
p += vsnprintf(p, end - p, fmt, ap);
if (p >= end || p < head_end) { /* Returned -1 in case of error... */
- static const char truncate_msg[12] = "[truncated] ";
+ static const char truncate_msg[12] = "[truncated] "; /* no NUL! */
memmove(head_end + sizeof(truncate_msg), head_end,
end - head_end - sizeof(truncate_msg));
memcpy(head_end, truncate_msg, sizeof(truncate_msg));
@@ -280,29 +280,33 @@ vsyslog( int pri, const char *fmt, va_list ap )
/* Output the message to the local logger using NUL as a message delimiter. */
p = tbuf;
*last_chr = 0;
- do {
- rc = write(LogFile, p, last_chr + 1 - p);
- if (rc < 0) {
- if ((errno==EAGAIN) || (errno==EINTR))
- rc=0;
- else {
- closelog_intern(0);
- break;
+ if (LogFile >= 0) {
+ do {
+ rc = write(LogFile, p, last_chr + 1 - p);
+ if (rc < 0) {
+ /* I don't think looping forever on EAGAIN is a good idea.
+ * Imagine that syslogd is SIGSTOPed... */
+ if (/* (errno != EAGAIN) && */ (errno != EINTR)) {
+ closelog_intern(1); /* 1: reset LogXXX globals to default */
+ goto write_err;
+ }
+ rc = 0;
}
- }
- p+=rc;
- } while (p <= last_chr);
- if (rc >= 0)
+ p += rc;
+ } while (p <= last_chr);
goto getout;
+ }
+ write_err:
/*
* Output the message to the console; don't worry about blocking,
* if console blocks everything will. Make sure the error reported
* is the one from the syslogd failure.
*/
- /* should mode be `O_WRONLY | O_NOCTTY' ? -- Uli */
- if (LogStat & LOG_CONS &&
- (fd = open(_PATH_CONSOLE, O_WRONLY, 0)) >= 0) {
+ /* should mode be O_WRONLY | O_NOCTTY? -- Uli */
+ /* yes, but in Linux "/dev/console" never becomes ctty anyway -- vda */
+ if ((LogStat & LOG_CONS) &&
+ (fd = open(_PATH_CONSOLE, O_WRONLY)) >= 0) {
p = strchr(tbuf, '>') + 1;
last_chr[0] = '\r';
last_chr[1] = '\n';
@@ -334,7 +338,7 @@ libc_hidden_def(syslog)
void
closelog( void )
{
- closelog_intern(1);
+ closelog_intern(0); /* 0: do not reset LogXXX globals to default */
}
libc_hidden_def(closelog)