--- /dev/null
+From 4053ba7cfb5255c0e6832781aebc909666b2e984 Mon Sep 17 00:00:00 2001
+From: Paul Eggert <eggert@cs.ucla.edu>
+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;