internals: added amgc_dprintf(), a signal-resilient dprintf implementation.

2 files changed, 62 insertions, 0 deletions

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