From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org, Paul Eggert <eggert@cs.ucla.edu>
Subject: [PATCH v5 4/7] misc: syslog: Simplify implementation
Date: Mon, 21 Mar 2022 18:19:10 -0300 [thread overview]
Message-ID: <20220321211913.2347924-5-adhemerval.zanella@linaro.org> (raw)
In-Reply-To: <20220321211913.2347924-1-adhemerval.zanella@linaro.org>
Use a temporary buffer for strftime instead of using internal libio
members, simplify fprintf call on the memstream and memory allocation,
use %b instead of %h, use dprintf instead of writev for LOG_PERROR.
Checked on x86_64-linux-gnu and i686-linux-gnu.
---
misc/syslog.c | 95 ++++++++++++++-------------------------------------
1 file changed, 26 insertions(+), 69 deletions(-)
diff --git a/misc/syslog.c b/misc/syslog.c
index 3b3b757a9a..c9db35b8c8 100644
--- a/misc/syslog.c
+++ b/misc/syslog.c
@@ -42,8 +42,6 @@ static char sccsid[] = "@(#)syslog.c 8.4 (Berkeley) 3/18/94";
#include <sys/un.h>
#include <syslog.h>
-#define ftell(s) _IO_ftell (s)
-
static int LogType = SOCK_DGRAM; /* type of socket connection */
static int LogFile = -1; /* fd for log */
static bool connected; /* have done connect */
@@ -122,13 +120,10 @@ void
__vsyslog_internal (int pri, const char *fmt, va_list ap,
unsigned int mode_flags)
{
- struct tm now_tm;
- time_t now;
- int fd;
FILE *f;
char *buf = 0;
size_t bufsize = 0;
- size_t msgoff;
+ int msgoff;
int saved_errno = errno;
char failbuf[3 * sizeof (pid_t) + sizeof "out of memory []"];
@@ -142,9 +137,7 @@ __vsyslog_internal (int pri, const char *fmt, va_list ap,
/* Prepare for multiple users. We have to take care: most syscalls we are
using are cancellation points. */
- struct cleanup_arg clarg;
- clarg.buf = NULL;
- clarg.oldaction = NULL;
+ struct cleanup_arg clarg = { NULL, NULL };
__libc_cleanup_push (cancel_handler, &clarg);
__libc_lock_lock (syslog_lock);
@@ -158,51 +151,22 @@ __vsyslog_internal (int pri, const char *fmt, va_list ap,
/* Build the message in a memory-buffer stream. */
f = __open_memstream (&buf, &bufsize);
- if (f == NULL)
- {
- /* We cannot get a stream. There is not much we can do but emitting an
- error messages. */
- char numbuf[3 * sizeof (pid_t)];
- char *nump;
- char *endp = __stpcpy (failbuf, "out of memory [");
- pid_t pid = __getpid ();
-
- nump = numbuf + sizeof (numbuf);
- /* The PID can never be zero. */
- do
- *--nump = '0' + pid % 10;
- while ((pid /= 10) != 0);
-
- endp = __mempcpy (endp, nump, (numbuf + sizeof (numbuf)) - nump);
- *endp++ = ']';
- *endp = '\0';
- buf = failbuf;
- bufsize = endp - failbuf;
- msgoff = 0;
- }
- else
+ if (f != NULL)
{
__fsetlocking (f, FSETLOCKING_BYCALLER);
- fprintf (f, "<%d>", pri);
- now = time_now ();
- f->_IO_write_ptr += __strftime_l (f->_IO_write_ptr,
- f->_IO_write_end - f->_IO_write_ptr,
- "%h %e %T ",
- __localtime_r (&now, &now_tm),
- _nl_C_locobj_ptr);
- msgoff = ftell (f);
- if (LogTag == NULL)
- LogTag = __progname;
- if (LogTag != NULL)
- __fputs_unlocked (LogTag, f);
- if (LogStat & LOG_PID)
- fprintf (f, "[%d]", (int) __getpid ());
- if (LogTag != NULL)
- {
- __putc_unlocked (':', f);
- __putc_unlocked (' ', f);
- }
-
+ /* "%b %e %H:%M:%S" */
+ char timebuf[sizeof "MMM DD hh:mm:ss "];
+ time_t now = time_now ();
+ struct tm now_tm;
+ __localtime_r (&now, &now_tm);
+ __strftime_l (timebuf, sizeof (timebuf), "%b %e %T", &now_tm,
+ _nl_C_locobj_ptr);
+
+ pid_t pid = LogStat & LOG_PID ? __getpid () : 0;
+
+ fprintf (f, "<%d>%s %n%s%s%.0d%s: ", pri, timebuf, &msgoff,
+ LogTag == NULL ? __progname : LogTag,
+ pid != 0 ? "[" : "", pid, pid != 0 ? "]" : "");
/* Restore errno for %m format. */
__set_errno (saved_errno);
@@ -216,26 +180,18 @@ __vsyslog_internal (int pri, const char *fmt, va_list ap,
/* Tell the cancellation handler to free this buffer. */
clarg.buf = buf;
}
+ else
+ {
+ /* Nothing much to do but emit an error message. */
+ bufsize = __snprintf (failbuf, sizeof failbuf, "out of memory[%d]",
+ __getpid ());
+ buf = failbuf;
+ }
/* Output to stderr if requested. */
if (LogStat & LOG_PERROR)
- {
- struct iovec iov[2];
- struct iovec *v = iov;
-
- v->iov_base = buf + msgoff;
- v->iov_len = bufsize - msgoff;
- /* Append a newline if necessary. */
- if (buf[bufsize - 1] != '\n')
- {
- ++v;
- v->iov_base = (char *) "\n";
- v->iov_len = 1;
- }
-
- /* writev is a cancellation point. */
- __writev (STDERR_FILENO, iov, v - iov + 1);
- }
+ __dprintf (STDERR_FILENO, "%s%s", buf + msgoff,
+ "\n" + (buf[bufsize - 1] == '\n'));
/* Get connected, output the message to the local logger. */
if (!connected)
@@ -264,6 +220,7 @@ __vsyslog_internal (int pri, const char *fmt, va_list ap,
* Make sure the error reported is the one from the
* syslogd failure.
*/
+ int fd;
if (LogStat & LOG_CONS &&
(fd = __open (_PATH_CONSOLE, O_WRONLY | O_NOCTTY
| O_CLOEXEC, 0)) >= 0)
--
2.32.0
next prev parent reply other threads:[~2022-03-21 21:19 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-21 21:19 [PATCH v5 0/7] Refactor syslog implementation Adhemerval Zanella
2022-03-21 21:19 ` [PATCH v5 1/7] support: Add xmkfifo Adhemerval Zanella
2022-03-21 21:19 ` [PATCH v5 2/7] misc: Add syslog test Adhemerval Zanella
2022-03-21 21:19 ` [PATCH v5 3/7] misc: syslog: Fix indentation and style Adhemerval Zanella
2022-03-21 21:19 ` Adhemerval Zanella [this message]
2022-03-21 21:19 ` [PATCH v5 5/7] misc: syslog: Use fixed-sized buffer and remove memstream Adhemerval Zanella
2022-03-21 21:19 ` [PATCH v5 6/7] misc: syslog: Move SYSLOG_NAME to USE_MISC (BZ #16355) Adhemerval Zanella
2022-03-21 21:19 ` [PATCH v5 7/7] misc: Use 64 bit time_t interfaces on syslog Adhemerval Zanella
[not found] ` <4c23c3a5-59fa-caa5-00d6-7392f6220b55@linaro.org>
[not found] ` <5780fdae-5b8e-e9ff-2e92-91343649a968@cs.ucla.edu>
[not found] ` <3ff164e7-c247-4275-a8d0-799c104b049e@linaro.org>
2022-04-14 22:12 ` [PATCH v5 0/7] Refactor syslog implementation Paul Eggert
2022-04-15 14:00 ` Adhemerval Zanella
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