fix: Resolve symlinks being written with size 0 in tar (coder#1488)

kylecarbs · web-flow · commit a77da8445e67 · 2022-05-16T20:26:23.000Z
Solution found here: https://stackoverflow.com/questions/38454850/getting-write-too-long-error-when-trying-to-create-tar-gz-file-from-file-and-d Symlink's were being written with a size of 0, which surfaced an error for write too long.
diff --git a/provisionersdk/archive.go b/provisionersdk/archive.go
@@ -25,7 +25,14 @@ func Tar(directory string, limit int64) ([]byte, error) {
 		if err != nil {
 			return err
 		}
-		header, err := tar.FileInfoHeader(fileInfo, file)
+		var link string
+		if fileInfo.Mode()&os.ModeSymlink == os.ModeSymlink {
+			link, err = os.Readlink(file)
+			if err != nil {
+				return err
+			}
+		}
+		header, err := tar.FileInfoHeader(fileInfo, link)
 		if err != nil {
 			return err
 		}
@@ -45,7 +52,7 @@ func Tar(directory string, limit int64) ([]byte, error) {
 		if err := tarWriter.WriteHeader(header); err != nil {
 			return err
 		}
-		if fileInfo.IsDir() {
+		if !fileInfo.Mode().IsRegular() {
 			return nil
 		}
 		data, err := os.Open(file)

Original file line number	Diff line number	Diff line change
`@@ -25,7 +25,14 @@ func Tar(directory string, limit int64) ([]byte, error) {`
`25`	`25`	`if err != nil {`
`26`	`26`	`return err`
`27`	`27`	`}`
`28`		`- header, err := tar.FileInfoHeader(fileInfo, file)`
	`28`	`+ var link string`
	`29`	`+ if fileInfo.Mode()&os.ModeSymlink == os.ModeSymlink {`
	`30`	`+ link, err = os.Readlink(file)`
	`31`	`+ if err != nil {`
	`32`	`+ return err`
	`33`	`+ }`
	`34`	`+ }`
	`35`	`+ header, err := tar.FileInfoHeader(fileInfo, link)`
`29`	`36`	`if err != nil {`
`30`	`37`	`return err`
`31`	`38`	`}`
`@@ -45,7 +52,7 @@ func Tar(directory string, limit int64) ([]byte, error) {`
`45`	`52`	`if err := tarWriter.WriteHeader(header); err != nil {`
`46`	`53`	`return err`
`47`	`54`	`}`
`48`		`- if fileInfo.IsDir() {`
	`55`	`+ if !fileInfo.Mode().IsRegular() {`
`49`	`56`	`return nil`
`50`	`57`	`}`
`51`	`58`	`data, err := os.Open(file)`