tools: tar: backport patch for paxlib shipped in tar

Tar 1.34 ship an old version of paxlib with rtapelib.c that produce some
compilation warning. This library got updated in 1.35 but we still can't
use the new Tar version.

GCC 14 then made these compilarion warning errors.

Manually backport the fixes to rtapelib.c and patch the version shipped
in 1.34 to fix these compilation warning.

Fixes: #15692
Fixes: 2951e0a80e9f ("tools: tar: backport patches fixing broken --delete")
Signed-off-by: Christian Marangi <[email protected]>

tools/tar/patches/003-Pacify-rtapelib.c-for-GCC-10-and-fix-a-bug-or-two.patch

@@ -0,0 +1,189 @@
+From 4053ba7cfb5255c0e6832781aebc909666b2e984 Mon Sep 17 00:00:00 2001
+From: Paul Eggert <[email protected]>
+Date: Sat, 27 Feb 2021 14:39:06 -0800
+Subject: [PATCH] Pacify rtapelib.c for GCC 10 and fix a bug or two
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This patch assumes C99, but that’s OK nowadays.
+* lib/rtapelib.c: Include verify.h.
+(rmt_open__): Tell GCC that remote_file must be nonnull.
+(rmt_read__, rmt_write__, rmt_lseek__, rmt_ioctl__):
+Properly size outgoing command buffers instead of guessing 64.
+Simplify by using C99 printf formats like %zu,
+as that’s a safe assumption nowadays.
+(rmt_ioctl__): 3rd arg is now void * not char *, to pacify gcc
+-Wcast-align.  Fix unlikely bug with short reads: ARGUMENT was
+being incremented, whereas later code wanted the original
+ARGUMENT.
+* paxlib.modules: Add ‘verify’.
+---
+ lib/rmt.h      |  2 +-
+ lib/rtapelib.c | 64 ++++++++++++++++++++------------------------------
+ paxlib.modules |  1 +
+ 3 files changed, 28 insertions(+), 39 deletions(-)
+
+--- a/lib/rmt.h
++++ b/lib/rmt.h
+@@ -25,7 +25,7 @@ int rmt_close__ (int);
+ size_t rmt_read__ (int, char *, size_t);
+ size_t rmt_write__ (int, char *, size_t);
+ off_t rmt_lseek__ (int, off_t, int);
+-int rmt_ioctl__ (int, int, char *);
++int rmt_ioctl__ (int, int, void *);
+ 
+ extern bool force_local_option;
+ 
+--- a/lib/rtapelib.c
++++ b/lib/rtapelib.c
+@@ -37,6 +37,7 @@
+ 
+ #include <safe-read.h>
+ #include <full-write.h>
++#include <verify.h>
+ 
+ /* Try hard to get EOPNOTSUPP defined.  486/ISC has it in net/errno.h,
+    3B2/SVR3 has it in sys/inet.h.  Otherwise, like on MSDOS, use EINVAL.  */
+@@ -424,6 +425,8 @@ rmt_open__ (const char *file_name, int o
+ 	}
+   }
+ 
++  assume (remote_file);
++
+   /* FIXME: Should somewhat validate the decoding, here.  */
+   if (gethostbyname (remote_host) == NULL)
+     error (EXIT_ON_EXEC_ERROR, 0, _("Cannot connect to %s: resolve failed"),
+@@ -567,12 +570,12 @@ rmt_close__ (int handle)
+ size_t
+ rmt_read__ (int handle, char *buffer, size_t length)
+ {
+-  char command_buffer[COMMAND_BUFFER_SIZE];
++  char command_buffer[sizeof "R\n" + INT_STRLEN_BOUND (size_t)];
+   size_t status;
+   size_t rlen;
+   size_t counter;
+ 
+-  sprintf (command_buffer, "R%lu\n", (unsigned long) length);
++  sprintf (command_buffer, "R%zu\n", length);
+   if (do_command (handle, command_buffer) == -1
+       || (status = get_status (handle)) == SAFE_READ_ERROR
+       || status > length)
+@@ -596,11 +599,11 @@ rmt_read__ (int handle, char *buffer, si
+ size_t
+ rmt_write__ (int handle, char *buffer, size_t length)
+ {
+-  char command_buffer[COMMAND_BUFFER_SIZE];
++  char command_buffer[sizeof "W\n" + INT_STRLEN_BOUND (size_t)];
+   RETSIGTYPE (*pipe_handler) (int);
+   size_t written;
+ 
+-  sprintf (command_buffer, "W%lu\n", (unsigned long) length);
++  sprintf (command_buffer, "W%zu\n", length);
+   if (do_command (handle, command_buffer) == -1)
+     return 0;
+ 
+@@ -628,17 +631,7 @@ rmt_write__ (int handle, char *buffer, s
+ off_t
+ rmt_lseek__ (int handle, off_t offset, int whence)
+ {
+-  char command_buffer[COMMAND_BUFFER_SIZE];
+-  char operand_buffer[UINTMAX_STRSIZE_BOUND];
+-  uintmax_t u = offset < 0 ? - (uintmax_t) offset : (uintmax_t) offset;
+-  char *p = operand_buffer + sizeof operand_buffer;
+-
+-  *--p = 0;
+-  do
+-    *--p = '0' + (int) (u % 10);
+-  while ((u /= 10) != 0);
+-  if (offset < 0)
+-    *--p = '-';
++  char command_buffer[sizeof "L\n0\n" + INT_STRLEN_BOUND (+offset)];
+ 
+   switch (whence)
+     {
+@@ -648,7 +641,8 @@ rmt_lseek__ (int handle, off_t offset, i
+     default: abort ();
+     }
+ 
+-  sprintf (command_buffer, "L%s\n%d\n", p, whence);
++  intmax_t off = offset;
++  sprintf (command_buffer, "L%jd\n%d\n", off, whence);
+ 
+   if (do_command (handle, command_buffer) == -1)
+     return -1;
+@@ -659,7 +653,7 @@ rmt_lseek__ (int handle, off_t offset, i
+ /* Perform a raw tape operation on remote tape connection HANDLE.
+    Return the results of the ioctl, or -1 on error.  */
+ int
+-rmt_ioctl__ (int handle, int operation, char *argument)
++rmt_ioctl__ (int handle, int operation, void *argument)
+ {
+   switch (operation)
+     {
+@@ -670,24 +664,16 @@ rmt_ioctl__ (int handle, int operation,
+ #ifdef MTIOCTOP
+     case MTIOCTOP:
+       {
+-	char command_buffer[COMMAND_BUFFER_SIZE];
+-	char operand_buffer[UINTMAX_STRSIZE_BOUND];
+-	uintmax_t u = (((struct mtop *) argument)->mt_count < 0
+-		       ? - (uintmax_t) ((struct mtop *) argument)->mt_count
+-		       : (uintmax_t) ((struct mtop *) argument)->mt_count);
+-	char *p = operand_buffer + sizeof operand_buffer;
+-
+-        *--p = 0;
+-	do
+-	  *--p = '0' + (int) (u % 10);
+-	while ((u /= 10) != 0);
+-	if (((struct mtop *) argument)->mt_count < 0)
+-	  *--p = '-';
++	struct mtop *mtop = argument;
++	enum { oplen = INT_STRLEN_BOUND (+mtop->mt_op) };
++	enum { countlen = INT_STRLEN_BOUND (+mtop->mt_count) };
++	char command_buffer[sizeof "I\n\n" + oplen + countlen];
+ 
+ 	/* MTIOCTOP is the easy one.  Nothing is transferred in binary.  */
+ 
+-	sprintf (command_buffer, "I%d\n%s\n",
+-		 ((struct mtop *) argument)->mt_op, p);
++	verify (EXPR_SIGNED (mtop->mt_count));
++	intmax_t count = mtop->mt_count;
++	sprintf (command_buffer, "I%d\n%jd\n", mtop->mt_op, count);
+ 	if (do_command (handle, command_buffer) == -1)
+ 	  return -1;
+ 
+@@ -717,9 +703,9 @@ rmt_ioctl__ (int handle, int operation,
+ 	    return -1;
+ 	  }
+ 
+-	for (; status > 0; status -= counter, argument += counter)
++	for (char *p = argument; status > 0; status -= counter, p += counter)
+ 	  {
+-	    counter = safe_read (READ_SIDE (handle), argument, status);
++	    counter = safe_read (READ_SIDE (handle), p, status);
+ 	    if (counter == SAFE_READ_ERROR || counter == 0)
+ 	      {
+ 		_rmt_shutdown (handle, EIO);
+@@ -732,15 +718,17 @@ rmt_ioctl__ (int handle, int operation,
+ 	   than 256, we will assume that the bytes are swapped and go through
+ 	   and reverse all the bytes.  */
+ 
+-	if (((struct mtget *) argument)->MTIO_CHECK_FIELD < 256)
++	struct mtget *mtget = argument;
++	if (mtget->MTIO_CHECK_FIELD < 256)
+ 	  return 0;
+ 
++	char *buf = argument;
+ 	for (counter = 0; counter < status; counter += 2)
+ 	  {
+-	    char copy = argument[counter];
++	    char copy = buf[counter];
+ 
+-	    argument[counter] = argument[counter + 1];
+-	    argument[counter + 1] = copy;
++	    buf[counter] = buf[counter + 1];
++	    buf[counter + 1] = copy;
+ 	  }
+ 
+ 	return 0;