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366e3746c5
The next patch in this series adds a common helper routine for both
memory reads and writes, like this:
static int
proc_xfer_memory (CORE_ADDR memaddr, unsigned char *readbuf,
const gdb_byte *writebuf, int len)
{
gdb_assert ((readbuf == nullptr) != (writebuf == nullptr));
...
}
int
linux_process_target::read_memory (CORE_ADDR memaddr,
unsigned char *myaddr, int len)
{
return proc_xfer_memory (memaddr, myaddr, nullptr, len);
}
linux_process_target::write_memory (CORE_ADDR memaddr,
const unsigned char *myaddr, int len)
{
return proc_xfer_memory (memaddr, nullptr, myaddr, len);
}
Surprisingly, the assertion fails. That happens because it can happen
that target_write_memory is called with LEN==0, due to this in
gdb/remote.c:
/* Determine whether the remote target supports binary downloading.
This is accomplished by sending a no-op memory write of zero length
to the target at the specified address. (...) */
void
remote_target::check_binary_download (CORE_ADDR addr)
{
...
p = rs->buf.data ();
*p++ = 'X';
p += hexnumstr (p, (ULONGEST) addr);
*p++ = ',';
p += hexnumstr (p, (ULONGEST) 0);
*p++ = ':';
*p = '\0';
In this scenario, in gdbserver's target_write_memory, the "myaddr"
argument of the_target->write_memory is passed the data() of a local
gdb::byte_vector (which is a specialized std::vector). It's valid for
std::vector::data() to return NULL when the vector is empty.
This commit adds an early return to target_write_memory to avoid
target backends having to care about this. For good measure, do the
same on the read side, in read_inferior_memory.
Change-Id: Iac8f04fcf99014c624ef4036bd318ca1771ad491
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.