From f72a4025ada2230fea795b9e43c58490fb0fc6b3 Mon Sep 17 00:00:00 2001
From: midipix <writeonce@midipix.org>
Date: Sat, 14 Jul 2018 12:39:38 -0400
Subject: internals: added amgc_dprintf(), a signal-resilient dprintf
 implementation.

---
 project/common.mk                    |  1 +
 project/headers.mk                   |  1 +
 src/internal/apimagic_dprintf_impl.c | 56 ++++++++++++++++++++++++++++++++++++
 src/internal/apimagic_dprintf_impl.h |  6 ++++
 4 files changed, 64 insertions(+)
 create mode 100644 src/internal/apimagic_dprintf_impl.c
 create mode 100644 src/internal/apimagic_dprintf_impl.h

diff --git a/project/common.mk b/project/common.mk
index 45c3178..c6a7dd8 100644
--- a/project/common.mk
+++ b/project/common.mk
@@ -17,6 +17,7 @@ API_SRCS = \
 	src/skin/amgc_skin_default.c \
 
 INTERNAL_SRCS = \
+	src/internal/$(PACKAGE)_dprintf_impl.c \
 	src/internal/$(PACKAGE)_errinfo_impl.c \
 
 APP_SRCS = \
diff --git a/project/headers.mk b/project/headers.mk
index 1f50364..0c357bc 100644
--- a/project/headers.mk
+++ b/project/headers.mk
@@ -4,6 +4,7 @@ API_HEADERS = \
 
 INTERNAL_HEADERS = \
 	$(PROJECT_DIR)/src/internal/argv/argv.h \
+	$(PROJECT_DIR)/src/internal/$(PACKAGE)_dprintf_impl.h \
 	$(PROJECT_DIR)/src/internal/$(PACKAGE)_driver_impl.h \
 	$(PROJECT_DIR)/src/internal/$(PACKAGE)_errinfo_impl.h \
 
diff --git a/src/internal/apimagic_dprintf_impl.c b/src/internal/apimagic_dprintf_impl.c
new file mode 100644
index 0000000..40146d2
--- /dev/null
+++ b/src/internal/apimagic_dprintf_impl.c
@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+int amgc_dprintf(int fd, const char * fmt, ...)
+{
+	int	ret;
+	int	cnt;
+	int	size;
+	va_list	ap;
+	char *	ch;
+	char *	buf;
+	char	chbuf[2048];
+
+	va_start(ap,fmt);
+
+	size = sizeof(chbuf);
+	buf  = ((cnt = vsnprintf(chbuf,size,fmt,ap)) < size)
+		? chbuf : malloc(cnt + 1);
+
+	va_end(ap);
+
+	if (buf == chbuf) {
+		(void)0;
+
+	} else if (buf) {
+		va_start(ap,fmt);
+		vsprintf(buf,fmt,ap);
+		va_end(ap);
+
+	} else {
+		return -1;
+	}
+
+	ret = 0;
+	ch  = buf;
+
+	for (; cnt && ret>=0; ) {
+		ret = write(fd,ch,cnt);
+
+		while ((ret < 0) && (errno == EINTR))
+			ret = write(fd,ch,cnt);
+
+		ch  += ret;
+		cnt -= ret;
+	}
+
+	ret = (ret < 0) ? -1 : ch - buf;
+
+	if (buf != chbuf)
+		free(buf);
+
+	return ret;
+}
diff --git a/src/internal/apimagic_dprintf_impl.h b/src/internal/apimagic_dprintf_impl.h
new file mode 100644
index 0000000..becc889
--- /dev/null
+++ b/src/internal/apimagic_dprintf_impl.h
@@ -0,0 +1,6 @@
+#ifndef APIMAGIC_DPRINTF_IMPL_H
+#define APIMAGIC_DPRINTF_IMPL_H
+
+int amgc_dprintf(int fd, const char * fmt, ...);
+
+#endif
-- 
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