A VFIL_writefile function similar to VFIL_readfile

include/vfil.h

@@ -33,6 +33,7 @@ struct vfil_path;
 /* from libvarnish/vfil.c */
 int seed_random(void);
 char *VFIL_readfile(const char *pfx, const char *fn, ssize_t *sz);
+int VFIL_writefile(const char *pfx, const char *fn, const char *buf, size_t sz);
 int VFIL_nonblocking(int fd);
 int VFIL_fsinfo(int fd, unsigned *pbs, uintmax_t *size, uintmax_t *space);
 int VFIL_allocate(int fd, off_t size, int insist);

lib/libvarnish/vfil.c

@@ -85,6 +85,24 @@ vfil_readfd(int fd, ssize_t *sz)
 	return (f);
 }
 
+static int
+vfil_writefd(int fd, const char *buf, size_t sz)
+{
+	ssize_t len;
+
+	while (sz > 0) {
+		len = write(fd, buf, sz);
+		if (len < 0)
+			return (len);
+		if (len == 0)
+			break;
+		buf += len;
+		sz -= len;
+	}
+
+	return (sz == 0 ? 0 : -1);
+}
+
 static int
 vfil_openfile(const char *pfx, const char *fn, int flags, int mode)
 {
@@ -118,6 +136,22 @@ VFIL_readfile(const char *pfx, const char *fn, ssize_t *sz)
 	return (r);
 }
 
+int
+VFIL_writefile(const char *pfx, const char *fn, const char *buf, size_t sz)
+{
+	int fd, err;
+	int r;
+
+	fd = vfil_openfile(pfx, fn, O_WRONLY|O_CREAT|O_TRUNC, 0660);
+	if (fd < 0)
+		return (fd);
+	r = vfil_writefd(fd, buf, sz);
+	err = errno;
+	AZ(close(fd));
+	errno = err;
+	return (r);
+}
+
 int
 VFIL_nonblocking(int fd)
 {