[Bug-tar] [PATCH] PAX format defaults to omitting PID

[Zachary Vance]

The intent is to make binary equivalent PAX archives easy to create. If POS
IXLY_CORRECT is set, the POSIX standard default is used, which embeds the p
id.

* src/buffer.c (add_chunk_header): Change filenames of multipart files to o
mit
   the pid
* src/xheader.c (xheader_xhdr_name, xheader_ghdr_name): Change default form
   at
   of PAX headers unless POSIXLY_CORRECT is set

Signed-off-by: Zachary Vance <address@hidden>
---
 doc/tar.texi  | 34 ++++++++++++++++------------------
 src/buffer.c  |  2 +-
 src/xheader.c | 20 +++++++++++++++-----
 3 files changed, 32 insertions(+), 24 deletions(-)

diff --git a/doc/tar.texi b/doc/tar.texi
index 96f6aeb..747f2f1 100644
--- a/doc/tar.texi
+++ b/doc/tar.texi
@@ -9975,7 +9975,7 @@ If no option @samp{exthdr.name=string} is specified, 
@command{tar}
 will use the following default value:
 
 @smallexample
-%d/PaxHeaders.%p/%f
+%d/PaxHeaders/%f
 @end smallexample
 
 @item address@hidden
@@ -10007,7 +10007,7 @@ If no option @samp{globexthdr.name=string} is 
specified, @command{tar}
 will use the following default value:
 
 @smallexample
-$TMPDIR/GlobalHead.%p.%n
+$TMPDIR/GlobalHead.%n
 @end smallexample
 
 @noindent
@@ -10074,7 +10074,7 @@ archives created using it, will be binary equivalent if 
they have the
 same contents:
 
 @smallexample
---pax-option=exthdr.name=%d/PaxHeaders/%f,atime:=0
+--pax-option=atime:=0
 @end smallexample
 
 @noindent
@@ -10083,14 +10083,14 @@ from them, you will also need to eliminate changes 
due to ctime, as
 shown in examples below:
 
 @smallexample
---pax-option=exthdr.name=%d/PaxHeaders/%f,atime:=0,ctime:=0
+--pax-option=atime:=0,ctime:=0
 @end smallexample
 
 @noindent
 or
 
 @smallexample
---pax-option=exthdr.name=%d/PaxHeaders/%f,atime:=0,delete=ctime
+--pax-option=atime:=0,delete=ctime
 @end smallexample
 
 @node Checksumming
@@ -10216,7 +10216,7 @@ GNU extensions.  More specifically, the very first part 
retains its
 original name, and all subsequent parts are named using the pattern:
 
 @smallexample
-%d/GNUFileParts.%p/%f.%n
+%d/GNUFileParts/%f.%n
 @end smallexample
 
 @noindent
@@ -10229,19 +10229,17 @@ have the following meaning:
 result of the @command{dirname} utility on its full name.
 @item %f @tab  The file name of the file, equivalent to the result
 of the @command{basename} utility on its full name.
address@hidden %p @tab  The process @acronym{ID} of the @command{tar} process 
that
 created the archive.
 @item %n @tab  Ordinal number of this particular part.
 @end multitable
 
 For example, if the file @file{var/longfile} was split during archive
-creation between three volumes, and the creator @command{tar} process
-had process @acronym{ID} @samp{27962}, then the member names will be:
+creation between three volumes then the member names will be:
 
 @smallexample
 var/longfile
-var/GNUFileParts.27962/longfile.1
-var/GNUFileParts.27962/longfile.2
+var/GNUFileParts/longfile.1
+var/GNUFileParts/longfile.2
 @end smallexample
 
 When you extract your archive using a third-party @command{tar}, these
@@ -10252,9 +10250,9 @@ the proper order, for example:
 @smallexample
 @group
 $ @kbd{cd var}
-$ @kbd{cat GNUFileParts.27962/longfile.1 \
-  GNUFileParts.27962/longfile.2 >> longfile}
-$ rm -f GNUFileParts.27962
+$ @kbd{cat GNUFileParts/longfile.1 \
+  GNUFileParts/longfile.2 >> longfile}
+$ rm -f GNUFileParts
 @end group
 @end smallexample
 
@@ -10280,17 +10278,17 @@ more warnings and more files generated on your disk, 
e.g.:
 @smallexample
 @group
 $ @kbd{tar xf vol-1.tar}
-var/PaxHeaders.27962/longfile: Unknown file type 'x', extracted as
+var/PaxHeaders/longfile: Unknown file type 'x', extracted as
 normal file
 Unexpected EOF in archive
 $ @kbd{tar xf vol-2.tar}
-tmp/GlobalHead.27962.1: Unknown file type 'g', extracted as normal file
-GNUFileParts.27962/PaxHeaders.27962/sparsefile.1: Unknown file type
+tmp/GlobalHead.1: Unknown file type 'g', extracted as normal file
+GNUFileParts/PaxHeaders/sparsefile.1: Unknown file type
 'x', extracted as normal file
 @end group
 @end smallexample
 
-Ignore these warnings.  The @file{PaxHeaders.*} directories created
+Ignore these warnings.  The @file{PaxHeaders} directories created
 will contain files with @dfn{extended header keywords} describing the
 extracted files.  You can delete them, unless they describe sparse
 members.  Read further to learn more about them.
diff --git a/src/buffer.c b/src/buffer.c
index 1a96595..ba41927 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1692,7 +1692,7 @@ add_chunk_header (struct bufmap *map)
       st.stat.st_uid = getuid ();
       st.stat.st_gid = getgid ();
       st.orig_file_name = xheader_format_name (&st,
-                                               "%d/GNUFileParts.%p/%f.%n",
+                                               "%d/GNUFileParts/%f.%n",
                                                volno);
       st.file_name = st.orig_file_name;
       st.archive_file_size = st.stat.st_size = map->sizeleft;
diff --git a/src/xheader.c b/src/xheader.c
index a5452a1..be57f81 100644
--- a/src/xheader.c
+++ b/src/xheader.c
@@ -362,13 +362,17 @@ xheader_format_name (struct tar_stat_info *st, const char 
*fmt, size_t n)
 char *
 xheader_xhdr_name (struct tar_stat_info *st)
 {
+  bool posixly_correct = (getenv ("POSIXLY_CORRECT") != NULL);
   if (!exthdr_name)
-    assign_string (&exthdr_name, "%d/PaxHeaders.%p/%f");
+    {
+      if (posixly_correct)
+        assign_string (&exthdr_name, "%d/PaxHeaders.%p/%f");
+      else
+        assign_string (&exthdr_name, "%d/PaxHeaders/%f");
+    }
   return xheader_format_name (st, exthdr_name, 0);
 }
 
-#define GLOBAL_HEADER_TEMPLATE "/GlobalHead.%p.%n"
-
 char *
 xheader_ghdr_name (void)
 {
@@ -378,10 +382,16 @@ xheader_ghdr_name (void)
       const char *tmp = getenv ("TMPDIR");
       if (!tmp)
        tmp = "/tmp";
-      len = strlen (tmp) + sizeof (GLOBAL_HEADER_TEMPLATE); /* Includes nul */
+      bool posixly_correct = (getenv ("POSIXLY_CORRECT") != NULL);
+      const char *global_header_template;
+      if (posixly_correct)
+        global_header_template = "/GlobalHead.%p.%n";
+      else
+        global_header_template = "/GlobalHead.%n";
+      len = strlen (tmp) + sizeof (global_header_template); /* Includes nul */
       globexthdr_name = xmalloc (len);
       strcpy(globexthdr_name, tmp);
-      strcat(globexthdr_name, GLOBAL_HEADER_TEMPLATE);
+      strcat(globexthdr_name, global_header_template);
     }
 
   return xheader_format_name (NULL, globexthdr_name, global_header_count + 1);
-- 
2.5.0