Merge branch 'for-next/misc'

2 files changed, 41 insertions, 10 deletions

diff --git a/fs/fs.c b/fs/fs.c
index 2b4659cfbb..1901c94ad1 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -910,6 +910,8 @@ loff_t lseek(int fildes, loff_t offset, int whence)
 	case SEEK_SET:
 		if (f->size != FILE_SIZE_STREAM && offset > f->size)
 			goto out;
+		if (offset < 0)
+			goto out;
 		pos = offset;
 		break;
 	case SEEK_CUR:
@@ -918,15 +920,21 @@ loff_t lseek(int fildes, loff_t offset, int whence)
 		pos = f->pos + offset;
 		break;
 	case SEEK_END:
-		if (offset)
+		if (offset > 0)
 			goto out;
-		pos = f->size;
+		pos = f->size + offset;
 		break;
 	default:
 		goto out;
 	}
 
-	return fsdrv->lseek(&f->fsdev->dev, f, pos);
+	pos = fsdrv->lseek(&f->fsdev->dev, f, pos);
+	if (pos < 0) {
+		errno = -pos;
+		return -1;
+	}
+
+	return pos;
 
 out:
 	if (ret)
diff --git a/fs/tftp.c b/fs/tftp.c
index 56d4365d77..847921aa56 100644
--- a/fs/tftp.c
+++ b/fs/tftp.c
@@ -568,13 +568,11 @@ static int tftp_read(struct device_d *dev, FILE *f, void *buf, size_t insize)
 
 	while (insize) {
 		now = kfifo_get(priv->fifo, buf, insize);
+		outsize += now;
+		buf += now;
+		insize -= now;
 		if (priv->state == STATE_DONE)
-			return outsize + now;
-		if (now) {
-			outsize += now;
-			buf += now;
-			insize -= now;
-		}
+			return outsize;
 
 		if (TFTP_FIFO_SIZE - kfifo_len(priv->fifo) >= priv->blocksize)
 			tftp_send(priv);
@@ -591,7 +589,32 @@ static int tftp_read(struct device_d *dev, FILE *f, void *buf, size_t insize)
 
 static loff_t tftp_lseek(struct device_d *dev, FILE *f, loff_t pos)
 {
-	/* not implemented in tftp protocol */
+	/* We cannot seek backwards without reloading or caching the file */
+	if (pos >= f->pos) {
+		loff_t ret;
+		char *buf = xmalloc(1024);
+
+		while (pos > f->pos) {
+			size_t len = min_t(size_t, 1024, pos - f->pos);
+
+			ret = tftp_read(dev, f, buf, len);
+
+			if (!ret)
+				/* EOF, so the desired pos is invalid. */
+				ret = -EINVAL;
+			if (ret < 0)
+				goto out_free;
+
+			f->pos += ret;
+		}
+
+		ret = pos;
+
+out_free:
+		free(buf);
+		return ret;
+	}
+
 	return -ENOSYS;
 }