Write-blocking cleanup, largely thanks to Colin Percival (cperciva@).

   * If write block size is zero, don't block at all.
     This supports the unusual requirement of applications
     that need "no-delay" writes.
   * Expose _write_finish_entry() to give such applications more
     control over write boundaries.  (Normal applications do not
     need this, as entries are completed automatically.)
   * Correct the type of write callbacks; this is a minor API
     change that does not affect the ABI.
   * Correct the error handling in _write_next_header() around
     completing the previous entry.
   * Correct the documentation for block-size markers:  Remove
     docs for the long-defunct _read_set_block_size(); document
     all of the write block size manipulators.

MFC after: 14 days

10 files changed, 91 insertions, 34 deletions

diff --git a/lib/libarchive/Makefile b/lib/libarchive/Makefile
index a024f9a..ac67026 100644
--- a/lib/libarchive/Makefile
+++ b/lib/libarchive/Makefile
@@ -161,7 +161,6 @@ MLINKS+=	archive_read.3 archive_read_open_fd.3
 MLINKS+=	archive_read.3 archive_read_open_file.3
 MLINKS+=	archive_read.3 archive_read_open_filename.3
 MLINKS+=	archive_read.3 archive_read_open_memory.3
-MLINKS+=	archive_read.3 archive_read_set_bytes_per_block.3
 MLINKS+=	archive_read.3 archive_read_support_compression_all.3
 MLINKS+=	archive_read.3 archive_read_support_compression_bzip2.3
 MLINKS+=	archive_read.3 archive_read_support_compression_compress.3
@@ -181,6 +180,9 @@ MLINKS+=	archive_util.3 archive_format_name.3
 MLINKS+=	archive_util.3 archive_set_error.3
 MLINKS+=	archive_write.3 archive_write_data.3
 MLINKS+=	archive_write.3 archive_write_finish.3
+MLINKS+=	archive_write.3 archive_write_finish_entry.3
+MLINKS+=	archive_write.3 archive_write_get_bytes_in_last_block.3
+MLINKS+=	archive_write.3 archive_write_get_bytes_per_block.3
 MLINKS+=	archive_write.3 archive_write_header.3
 MLINKS+=	archive_write.3 archive_write_new.3
 MLINKS+=	archive_write.3 archive_write_open.3
diff --git a/lib/libarchive/archive.h.in b/lib/libarchive/archive.h.in
index 4567de7..e0fe3e0 100644
--- a/lib/libarchive/archive.h.in
+++ b/lib/libarchive/archive.h.in
@@ -116,7 +116,7 @@ typedef ssize_t	archive_skip_callback(struct archive *, void *_client_data,
 		    size_t request);
 /* Returns size actually written, zero on EOF, -1 on error. */
 typedef ssize_t	archive_write_callback(struct archive *, void *_client_data,
-		    void *_buffer, size_t _length);
+		    const void *_buffer, size_t _length);
 typedef int	archive_open_callback(struct archive *, void *_client_data);
 typedef int	archive_close_callback(struct archive *, void *_client_data);
 
@@ -358,6 +358,7 @@ int		 archive_write_header(struct archive *,
 		     struct archive_entry *);
 /* TODO: should be ssize_t, but that might require .so version bump? */
 int		 archive_write_data(struct archive *, const void *, size_t);
+int		 archive_write_finish_entry(struct archive *);
 int		 archive_write_close(struct archive *);
 void		 archive_write_finish(struct archive *);
 
diff --git a/lib/libarchive/archive_read.3 b/lib/libarchive/archive_read.3
index 7beb90e..cde80c9 100644
--- a/lib/libarchive/archive_read.3
+++ b/lib/libarchive/archive_read.3
@@ -29,7 +29,6 @@
 .Os
 .Sh NAME
 .Nm archive_read_new ,
-.Nm archive_read_set_bytes_per_block ,
 .Nm archive_read_support_compression_all ,
 .Nm archive_read_support_compression_bzip2 ,
 .Nm archive_read_support_compression_compress ,
@@ -62,8 +61,6 @@
 .Ft struct archive *
 .Fn archive_read_new "void"
 .Ft int
-.Fn archive_read_set_bytes_per_block "struct archive *" "int"
-.Ft int
 .Fn archive_read_support_compression_all "struct archive *"
 .Ft int
 .Fn archive_read_support_compression_bzip2 "struct archive *"
@@ -129,11 +126,6 @@ order they would be used:
 Allocates and initializes a
 .Tn struct archive
 object suitable for reading from an archive.
-.It Fn archive_read_set_bytes_per_block
-Sets the block size used for reading the archive data.
-This controls the size that will be used when invoking the read
-callback function.
-The default is 20 records or 10240 bytes for tar formats.
 .It Fn archive_read_support_compression_all , Fn archive_read_support_compression_bzip2 , Fn archive_read_support_compression_compress , Fn archive_read_support_compression_gzip , Fn archive_read_support_compression_none
 Enables auto-detection code and decompression support for the
 specified compression.
diff --git a/lib/libarchive/archive_write.3 b/lib/libarchive/archive_write.3
index cb2b6a0..756d67d 100644
--- a/lib/libarchive/archive_write.3
+++ b/lib/libarchive/archive_write.3
@@ -35,6 +35,7 @@
 .Nm archive_write_set_format_shar ,
 .Nm archive_write_set_format_shar_binary ,
 .Nm archive_write_set_format_ustar ,
+.Nm archive_write_get_bytes_per_block ,
 .Nm archive_write_set_bytes_per_block ,
 .Nm archive_write_set_bytes_in_last_block ,
 .Nm archive_write_set_compressor_gzip ,
@@ -46,6 +47,7 @@
 .Nm archive_write_open_memory ,
 .Nm archive_write_header ,
 .Nm archive_write_data ,
+.Nm archive_write_finish_entry ,
 .Nm archive_write_close ,
 .Nm archive_write_finish
 .Nd functions for creating archives
@@ -54,6 +56,8 @@
 .Ft struct archive *
 .Fn archive_write_new "void"
 .Ft int
+.Fn archive_write_get_bytes_per_block "struct archive *"
+.Ft int
 .Fn archive_write_set_bytes_per_block "struct archive *" "int bytes_per_block"
 .Ft int
 .Fn archive_write_set_bytes_in_last_block "struct archive *" "int"
@@ -88,6 +92,8 @@
 .Ft int
 .Fn archive_write_data "struct archive *" "const void *" "size_t"
 .Ft int
+.Fn archive_write_finish_entry "struct archive *"
+.Ft int
 .Fn archive_write_close "struct archive *"
 .Ft void
 .Fn archive_write_finish "struct archive *"
@@ -114,6 +120,12 @@ written will be padded to the full block size.
 If it is zero, the last block will not be padded.
 If it is non-zero, padding will be added both before and after compression.
 The default is to use a block size of 10240 bytes and to pad the last block.
+Note that a block size of zero will suppress internal blocking
+and cause writes to be sent directly to the write callback as they occur.
+.It Fn archive_write_get_bytes_per_block
+Retrieve the block size to be used for writing.
+A value of -1 here indicates that the library should use default values.
+A value of zero indicates that internal blocking is suppressed.
 .It Fn archive_write_set_bytes_in_last_block
 Sets the block size used for writing the last block.
 If this value is zero, the last block will be padded to the same size
@@ -129,6 +141,9 @@ will set this based on the file type).
 Unlike the other
 .Dq set
 functions, this function can be called after the archive is opened.
+.It Fn archive_write_get_bytes_in_last_block
+Retrieve the currently-set value for last block size.
+A value of -1 here indicates that the library should use default values.
 .It Fn archive_write_set_format_cpio , Fn archive_write_set_format_pax , Fn archive_write_set_format_pax_restricted , Fn archive_write_set_format_shar , Fn archive_write_set_format_shar_binary , Fn archive_write_set_format_ustar
 Sets the format that will be used for the archive.
 The library can write
@@ -230,6 +245,15 @@ objects.
 .It Fn archive_write_data
 Write data corresponding to the header just written.
 Returns number of bytes written or -1 on error.
+.It Fn archive_write_finish_entry
+Close out the entry just written.
+In particular, this writes out the final padding required by some formats.
+Ordinarily, clients never need to call this, as it
+is called automatically by
+.Fn archive_write_next_header
+and
+.Fn archive_write_close
+as needed.
 .It Fn archive_write_close
 Complete the archive and invoke the close callback.
 .It Fn archive_write_finish
diff --git a/lib/libarchive/archive_write.c b/lib/libarchive/archive_write.c
index aa50c70..4b288bf 100644
--- a/lib/libarchive/archive_write.c
+++ b/lib/libarchive/archive_write.c
@@ -232,22 +232,22 @@ archive_write_finish(struct archive *a)
 	free(a);
 }
 
-
 /*
  * Write the appropriate header.
  */
 int
 archive_write_header(struct archive *a, struct archive_entry *entry)
 {
-	int ret;
+	int ret, r2;
 
 	__archive_check_magic(a, ARCHIVE_WRITE_MAGIC,
-	    ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA, "archive_write_header");
+	    ARCHIVE_STATE_DATA | ARCHIVE_STATE_HEADER, "archive_write_header");
 	archive_string_empty(&a->error_string);
 
-	/* Finish last entry. */
-	if (a->state & ARCHIVE_STATE_DATA)
-		((a->format_finish_entry)(a));
+	/* In particular, "retry" and "fatal" get returned immediately. */
+	ret = archive_write_finish_entry(a);
+	if (ret < ARCHIVE_OK && ret != ARCHIVE_WARN)
+		return (ret);
 
 	if (a->skip_file_dev != 0 &&
 	    archive_entry_dev(entry) == a->skip_file_dev &&
@@ -258,12 +258,28 @@ archive_write_header(struct archive *a, struct archive_entry *entry)
 	}
 
 	/* Format and write header. */
-	ret = ((a->format_write_header)(a, entry));
+	r2 = ((a->format_write_header)(a, entry));
+	if (r2 < ret)
+		ret = r2;
 
 	a->state = ARCHIVE_STATE_DATA;
 	return (ret);
 }
 
+int
+archive_write_finish_entry(struct archive * a)
+{
+	int ret = ARCHIVE_OK;
+
+	__archive_check_magic(a, ARCHIVE_WRITE_MAGIC,
+	    ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
+	    "archive_write_finish_entry");
+	if (a->state & ARCHIVE_STATE_DATA)
+		ret = (a->format_finish_entry)(a);
+	a->state = ARCHIVE_STATE_HEADER;
+	return (ret);
+}
+
 /*
  * Note that the compressor is responsible for blocking.
  */
@@ -271,7 +287,8 @@ archive_write_header(struct archive *a, struct archive_entry *entry)
 int
 archive_write_data(struct archive *a, const void *buff, size_t s)
 {
-	__archive_check_magic(a, ARCHIVE_WRITE_MAGIC, ARCHIVE_STATE_DATA, "archive_write_data");
+	__archive_check_magic(a, ARCHIVE_WRITE_MAGIC,
+	    ARCHIVE_STATE_DATA, "archive_write_data");
 	archive_string_empty(&a->error_string);
 	return ((a->format_write_data)(a, buff, s));
 }
diff --git a/lib/libarchive/archive_write_open_fd.c b/lib/libarchive/archive_write_open_fd.c
index 8f979f5..bf4a26b 100644
--- a/lib/libarchive/archive_write_open_fd.c
+++ b/lib/libarchive/archive_write_open_fd.c
@@ -52,7 +52,7 @@ struct write_fd_data {
 
 static int	file_close(struct archive *, void *);
 static int	file_open(struct archive *, void *);
-static ssize_t	file_write(struct archive *, void *, void *buff, size_t);
+static ssize_t	file_write(struct archive *, void *, const void *buff, size_t);
 
 int
 archive_write_open_fd(struct archive *a, int fd)
@@ -108,7 +108,7 @@ file_open(struct archive *a, void *client_data)
 }
 
 static ssize_t
-file_write(struct archive *a, void *client_data, void *buff, size_t length)
+file_write(struct archive *a, void *client_data, const void *buff, size_t length)
 {
 	struct write_fd_data	*mine;
 	ssize_t	bytesWritten;
diff --git a/lib/libarchive/archive_write_open_file.c b/lib/libarchive/archive_write_open_file.c
index 0eb1a03..b95693b 100644
--- a/lib/libarchive/archive_write_open_file.c
+++ b/lib/libarchive/archive_write_open_file.c
@@ -54,7 +54,7 @@ struct write_FILE_data {
 
 static int	file_close(struct archive *, void *);
 static int	file_open(struct archive *, void *);
-static ssize_t	file_write(struct archive *, void *, void *buff, size_t);
+static ssize_t	file_write(struct archive *, void *, const void *buff, size_t);
 
 int
 archive_write_open_FILE(struct archive *a, FILE *f)
@@ -81,7 +81,7 @@ file_open(struct archive *a, void *client_data)
 }
 
 static ssize_t
-file_write(struct archive *a, void *client_data, void *buff, size_t length)
+file_write(struct archive *a, void *client_data, const void *buff, size_t length)
 {
 	struct write_FILE_data	*mine;
 	size_t	bytesWritten;
diff --git a/lib/libarchive/archive_write_open_filename.c b/lib/libarchive/archive_write_open_filename.c
index c37caeb..8f2ece6 100644
--- a/lib/libarchive/archive_write_open_filename.c
+++ b/lib/libarchive/archive_write_open_filename.c
@@ -55,7 +55,7 @@ struct write_file_data {
 
 static int	file_close(struct archive *, void *);
 static int	file_open(struct archive *, void *);
-static ssize_t	file_write(struct archive *, void *, void *buff, size_t);
+static ssize_t	file_write(struct archive *, void *, const void *buff, size_t);
 
 int
 archive_write_open_file(struct archive *a, const char *filename)
@@ -143,7 +143,7 @@ file_open(struct archive *a, void *client_data)
 }
 
 static ssize_t
-file_write(struct archive *a, void *client_data, void *buff, size_t length)
+file_write(struct archive *a, void *client_data, const void *buff, size_t length)
 {
 	struct write_file_data	*mine;
 	ssize_t	bytesWritten;
diff --git a/lib/libarchive/archive_write_open_memory.c b/lib/libarchive/archive_write_open_memory.c
index 58baebd..120a79a 100644
--- a/lib/libarchive/archive_write_open_memory.c
+++ b/lib/libarchive/archive_write_open_memory.c
@@ -54,7 +54,7 @@ struct write_memory_data {
 
 static int	memory_write_close(struct archive *, void *);
 static int	memory_write_open(struct archive *, void *);
-static ssize_t	memory_write(struct archive *, void *, void *buff, size_t);
+static ssize_t	memory_write(struct archive *, void *, const void *buff, size_t);
 
 /*
  * Client provides a pointer to a block of memory to receive
@@ -100,7 +100,7 @@ memory_write_open(struct archive *a, void *client_data)
  * how much has been written into their buffer at any time.
  */
 static ssize_t
-memory_write(struct archive *a, void *client_data, void *buff, size_t length)
+memory_write(struct archive *a, void *client_data, const void *buff, size_t length)
 {
 	struct write_memory_data *mine;
 	mine = client_data;
diff --git a/lib/libarchive/archive_write_set_compression_none.c b/lib/libarchive/archive_write_set_compression_none.c
index 9e43365..3fdaa67 100644
--- a/lib/libarchive/archive_write_set_compression_none.c
+++ b/lib/libarchive/archive_write_set_compression_none.c
@@ -89,13 +89,14 @@ archive_compressor_none_init(struct archive *a)
 	memset(state, 0, sizeof(*state));
 
 	state->buffer_size = a->bytes_per_block;
-	state->buffer = (char *)malloc(state->buffer_size);
-
-	if (state->buffer == NULL) {
-		archive_set_error(a, ENOMEM,
-		    "Can't allocate output buffer");
-		free(state);
-		return (ARCHIVE_FATAL);
+	if (state->buffer_size != 0) {
+		state->buffer = (char *)malloc(state->buffer_size);
+		if (state->buffer == NULL) {
+			archive_set_error(a, ENOMEM,
+			    "Can't allocate output buffer");
+			free(state);
+			return (ARCHIVE_FATAL);
+		}
 	}
 
 	state->next = state->buffer;
@@ -129,7 +130,27 @@ archive_compressor_none_write(struct archive *a, const void *vbuff,
 	}
 
 	remaining = length;
-	while (remaining > 0) {
+
+	/*
+	 * If there is no buffer for blocking, just pass the data
+	 * straight through to the client write callback.  In
+	 * particular, this supports "no write delay" operation for
+	 * special applications.  Just set the block size to zero.
+	 */
+	if (state->buffer_size == 0) {
+		while (remaining > 0) {
+			bytes_written = (a->client_writer)(a, a->client_data,
+			    buff, remaining);
+			if (bytes_written <= 0)
+				return (ARCHIVE_FATAL);
+			remaining -= bytes_written;
+			buff += bytes_written;
+		}
+		a->file_position += length;
+		return (ARCHIVE_OK);
+	}
+
+	while ((remaining > 0) || (state->avail == 0)) {
 		/*
 		 * If we have a full output block, write it and reset the
 		 * output buffer.