httpd shring and logging update, part 1 or 7

   text    data     bss     dec     hex filename
   9836       0       0    9836    266c busybox.t1/networking/httpd.o.orig
   9724       0       0    9724    25fc busybox.t2/networking/httpd.o
   9657       0       0    9657    25b9 busybox.t3/networking/httpd.o
   9342       0       0    9342    247e busybox.t4/networking/httpd.o
   9342       0       0    9342    247e busybox.t5/networking/httpd.o
   9262       0       0    9262    242e busybox.t6/networking/httpd.o
   9283       0       0    9283    2443 busybox.t7/networking/httpd.o
   9334       0       0    9334    2476 busybox.t8/networking/httpd.o

2 files changed, 102 insertions, 28 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 912505026..52bc33940 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -642,8 +642,8 @@ enum { wrote_pidfile = 0 };
 
 enum {
 	LOGMODE_NONE = 0,
-	LOGMODE_STDIO = 1<<0,
-	LOGMODE_SYSLOG = 1<<1,
+	LOGMODE_STDIO = (1 << 0),
+	LOGMODE_SYSLOG = (1 << 1) * ENABLE_FEATURE_SYSLOG,
 	LOGMODE_BOTH = LOGMODE_SYSLOG + LOGMODE_STDIO,
 };
 extern const char *msg_eol;
diff --git a/libbb/verror_msg.c b/libbb/verror_msg.c
index 082e7bf3c..e51003134 100644
--- a/libbb/verror_msg.c
+++ b/libbb/verror_msg.c
@@ -7,45 +7,119 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include "libbb.h"
 #include <syslog.h>
+#include "libbb.h"
 
 smallint logmode = LOGMODE_STDIO;
 const char *msg_eol = "\n";
 
 void bb_verror_msg(const char *s, va_list p, const char* strerr)
 {
-	/* va_copy is used because it is not portable
-	 * to use va_list p twice */
-	va_list p2;
-	va_copy(p2, p);
+	char *msg;
+	int applet_len, strerr_len, msgeol_len, used;
+
+	if (!logmode)
+		return;
+
+	if (!s) /* nomsg[_and_die] uses NULL fmt */
+		s = ""; /* some libc don't like printf(NULL) */
+
+	used = vasprintf(&msg, s, p);
+	if (used < 0)
+		return;
+
+	/* This is ugly and costs +60 bytes compared to multiple
+	 * fprintf's, but is guaranteed to do a single write.
+	 * This is needed for e.g. httpd logging, when multiple
+	 * children can produce log messages simultaneously. */
+
+	applet_len = strlen(applet_name) + 2; /* "applet: " */
+	strerr_len = strerr ? strlen(strerr) : 0;
+	msgeol_len = strlen(msg_eol);
+	/* +3 is for ": " before strerr and for terminating NUL */
+	msg = xrealloc(msg, applet_len + used + strerr_len + msgeol_len + 3);
+	/* TODO: maybe use writev instead of memmoving? Need full_writev? */
+	memmove(msg + applet_len, msg, used);
+	used += applet_len;
+	strcpy(msg, applet_name);
+	msg[applet_len - 2] = ':';
+	msg[applet_len - 1] = ' ';
+	if (strerr) {
+		msg[used++] = ':';
+		msg[used++] = ' ';
+		strcpy(&msg[used], strerr);
+		used += strerr_len;
+	}
+	strcpy(&msg[used], msg_eol);
+
+	if (logmode & LOGMODE_STDIO) {
+		fflush(stdout);
+		full_write(2, msg, used + msgeol_len);
+	}
+	if (logmode & LOGMODE_SYSLOG) {
+		syslog(LOG_ERR, "%s", msg + applet_len);
+	}
+	free(msg);
+}
+
+
+#ifdef VERSION_WITH_WRITEV
+
+/* Code size is approximately the same, but currently it's the only user
+ * of writev in entire bbox. __libc_writev in uclibc is ~50 bytes. */
+
+void bb_verror_msg(const char *s, va_list p, const char* strerr)
+{
+	int strerr_len, msgeol_len;
+	struct iovec iov[3];
+
+#define used   (iov[2].iov_len)
+#define msgv   (iov[2].iov_base)
+#define msgc   ((char*)(iov[2].iov_base))
+#define msgptr (&(iov[2].iov_base))
+
+	if (!logmode)
+		return;
 
 	if (!s) /* nomsg[_and_die] uses NULL fmt */
 		s = ""; /* some libc don't like printf(NULL) */
 
+	/* Prevent "derefing type-punned ptr will break aliasing rules" */
+	used = vasprintf((char**)(void*)msgptr, s, p);
+	if (used < 0)
+		return;
+
+	/* This is ugly and costs +60 bytes compared to multiple
+	 * fprintf's, but is guaranteed to do a single write.
+	 * This is needed for e.g. httpd logging, when multiple
+	 * children can produce log messages simultaneously. */
+
+	strerr_len = strerr ? strlen(strerr) : 0;
+	msgeol_len = strlen(msg_eol);
+	/* +3 is for ": " before strerr and for terminating NUL */
+	msgv = xrealloc(msgv, used + strerr_len + msgeol_len + 3);
+	if (strerr) {
+		msgc[used++] = ':';
+		msgc[used++] = ' ';
+		strcpy(msgc + used, strerr);
+		used += strerr_len;
+	}
+	strcpy(msgc + used, msg_eol);
+	used += msgeol_len;
+
 	if (logmode & LOGMODE_STDIO) {
+		iov[0].iov_base = (char*)applet_name;
+		iov[0].iov_len = strlen(applet_name);
+		iov[1].iov_base = (char*)": ";
+		iov[1].iov_len = 2;
+		/*iov[2].iov_base = msgc;*/
+		/*iov[2].iov_len = used;*/
 		fflush(stdout);
-		fprintf(stderr, "%s: ", applet_name);
-		vfprintf(stderr, s, p);
-		if (!strerr)
-			fputs(msg_eol, stderr);
-		else
-			fprintf(stderr, "%s%s%s",
-					s[0] ? ": " : "",
-					strerr, msg_eol);
+		writev(2, iov, 3);
 	}
-	if (ENABLE_FEATURE_SYSLOG && (logmode & LOGMODE_SYSLOG)) {
-		if (!strerr)
-			vsyslog(LOG_ERR, s, p2);
-		else  {
-			char *msg;
-			if (vasprintf(&msg, s, p2) < 0) {
-				fprintf(stderr, "%s: %s\n", applet_name, bb_msg_memory_exhausted);
-				xfunc_die();
-			}
-			syslog(LOG_ERR, "%s: %s", msg, strerr);
-			free(msg);
-		}
+	if (logmode & LOGMODE_SYSLOG) {
+		syslog(LOG_ERR, "%s", msgc);
 	}
-	va_end(p2);
+	free(msgc);
 }
+#endif