diff options
| -rw-r--r-- | src/cmd/pack/doc.go | 4 | ||||
| -rw-r--r-- | src/cmd/pack/pack.go | 50 | ||||
| -rw-r--r-- | src/cmd/pack/pack_test.go | 23 |
3 files changed, 57 insertions, 20 deletions
diff --git a/src/cmd/pack/doc.go b/src/cmd/pack/doc.go index 1529e07e9..a702594e2 100644 --- a/src/cmd/pack/doc.go +++ b/src/cmd/pack/doc.go @@ -20,6 +20,10 @@ The operation op is given by one of these letters: t list files from the archive x extract files from the archive +The archive argument to the c command must be non-existent or a +valid archive file, which will be cleared before adding new entries. It +is an error if the file exists but is not an archive. + For the p, t, and x commands, listing no names on the command line causes the operation to apply to all files in the archive. diff --git a/src/cmd/pack/pack.go b/src/cmd/pack/pack.go index 594433712..ffb2d617a 100644 --- a/src/cmd/pack/pack.go +++ b/src/cmd/pack/pack.go @@ -142,16 +142,19 @@ type Archive struct { matchAll bool // match all files in archive } -// archive opens (or if necessary creates) the named archive. +// archive opens (and if necessary creates) the named archive. func archive(name string, mode int, files []string) *Archive { - fd, err := os.OpenFile(name, mode, 0) - if err != nil && mode&^os.O_TRUNC == os.O_RDWR && os.IsNotExist(err) { - fd, err = create(name) + // If the file exists, it must be an archive. If it doesn't exist, or if + // we're doing the c command, indicated by O_TRUNC, truncate the archive. + if !existingArchive(name) || mode&os.O_TRUNC != 0 { + create(name) + mode &^= os.O_TRUNC } + fd, err := os.OpenFile(name, mode, 0) if err != nil { log.Fatal(err) } - mustBeArchive(fd) + checkHeader(fd) return &Archive{ fd: fd, files: files, @@ -160,23 +163,40 @@ func archive(name string, mode int, files []string) *Archive { } // create creates and initializes an archive that does not exist. -func create(name string) (*os.File, error) { - fd, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644) +func create(name string) { + fd, err := os.Create(name) if err != nil { - return nil, err + log.Fatal(err) + } + _, err = fmt.Fprint(fd, arHeader) + if err != nil { + log.Fatal(err) + } + fd.Close() +} + +// existingArchive reports whether the file exists and is a valid archive. +// If it exists but is not an archive, existingArchive will exit. +func existingArchive(name string) bool { + fd, err := os.Open(name) + if err != nil { + if os.IsNotExist(err) { + return false + } + log.Fatal("cannot open file: %s", err) } - fmt.Fprint(fd, arHeader) - fd.Seek(0, 0) - return fd, nil + checkHeader(fd) + fd.Close() + return true } -// mustBeArchive verifies the header of the file. It assumes the file offset -// is 0 coming in, and leaves it positioned immediately after the header. -func mustBeArchive(fd *os.File) { +// checkHeader verifies the header of the file. It assumes the file +// is positioned at 0 and leaves it positioned at the end of the header. +func checkHeader(fd *os.File) { buf := make([]byte, len(arHeader)) _, err := io.ReadFull(fd, buf) if err != nil || string(buf) != arHeader { - log.Fatal("file is not an archive: bad header") + log.Fatal("%s is not an archive: bad header", fd.Name()) } } diff --git a/src/cmd/pack/pack_test.go b/src/cmd/pack/pack_test.go index e41cf3ce4..cf6121fcc 100644 --- a/src/cmd/pack/pack_test.go +++ b/src/cmd/pack/pack_test.go @@ -56,11 +56,8 @@ func tmpDir(t *testing.T) string { return name } -// Test that we can create an archive, write to it, and get the same contents back. -// Tests the rv and then the pv command on a new archive. -func TestCreate(t *testing.T) { - dir := tmpDir(t) - defer os.RemoveAll(dir) +// testCreate creates an archive in the specified directory. +func testCreate(t *testing.T, dir string) { name := filepath.Join(dir, "pack.a") ar := archive(name, os.O_RDWR, nil) // Add an entry by hand. @@ -85,6 +82,22 @@ func TestCreate(t *testing.T) { } } +// Test that we can create an archive, write to it, and get the same contents back. +// Tests the rv and then the pv command on a new archive. +func TestCreate(t *testing.T) { + dir := tmpDir(t) + defer os.RemoveAll(dir) + testCreate(t, dir) +} + +// Test that we can create an archive twice with the same name (Issue 8369). +func TestCreateTwice(t *testing.T) { + dir := tmpDir(t) + defer os.RemoveAll(dir) + testCreate(t, dir) + testCreate(t, dir) +} + // Test that we can create an archive, put some files in it, and get back a correct listing. // Tests the tv command. func TestTableOfContents(t *testing.T) { |