[PATCH] Add common write_memory and read_memory NetBSD routines
Kamil Rytarowski
n54@gmx.com
Wed Oct 7 04:13:52 GMT 2020
Instead of sharing the native-only code with all BSDs with slightly
different semantics of the kernels, share the NetBSD-only behavior beteen
the NetBSD native and gdbserver setup.
NetBSD does not differentiate the address space I and D in the
operations (contrary to OpenBSD). NetBSD handles EACCES that integrates
with NetBSD specific PaX MPROTECT error handling.
Add a verbose message in the native client that an operation could be
cancelled due to PaX MPROTECT setup.
gdb/ChangeLog:
* nat/netbsd-nat.c (write_memory, read_memory): Add.
* nat/netbsd-nat.h (write_memory, read_memory): Likewise.
* nbsd-nat.c (nbsd_nat_target::xfer_partial): Update.
gdbserver/ChangeLog:
* netbsd-low.cc (netbsd_process_target::read_memory)
(netbsd_process_target::write_memory): Update.
---
gdb/ChangeLog | 6 ++++
gdb/nat/netbsd-nat.c | 80 +++++++++++++++++++++++++++++++++++++++++
gdb/nat/netbsd-nat.h | 22 ++++++++++++
gdb/nbsd-nat.c | 23 ++++++++++++
gdbserver/ChangeLog | 5 +++
gdbserver/netbsd-low.cc | 61 ++-----------------------------
6 files changed, 138 insertions(+), 59 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 2744ad8e097..4d4c0cb3d90 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2020-10-07 Kamil Rytarowski <n54@gmx.com>
+
+ * nat/netbsd-nat.c (write_memory, read_memory): Add.
+ * nat/netbsd-nat.h (write_memory, read_memory): Likewise.
+ * nbsd-nat.c (nbsd_nat_target::xfer_partial): Update.
+
2020-10-06 Andrew Burgess <andrew.burgess@embecosm.com>
* symtab.c (find_pc_line): Return unmapped addresses when the
diff --git a/gdb/nat/netbsd-nat.c b/gdb/nat/netbsd-nat.c
index 41b67cb72fc..8316935f039 100644
--- a/gdb/nat/netbsd-nat.c
+++ b/gdb/nat/netbsd-nat.c
@@ -210,4 +210,84 @@ qxfer_siginfo (pid_t pid, const char *annex, unsigned char *readbuf,
return len;
}
+/* See netbsd-nat.h. */
+
+int
+write_memory (pid_t pid, unsigned const char *writebuf, CORE_ADDR offset,
+ size_t len, size_t *xfered_len)
+{
+ struct ptrace_io_desc io;
+ io.piod_op = PIOD_WRITE_D;
+ io.piod_len = len;
+
+ size_t bytes_written = 0;
+
+ /* Zero length write always succeeds. */
+ if (len > 0)
+ {
+ do
+ {
+ io.piod_addr = (void *)(writebuf + bytes_written);
+ io.piod_offs = (void *)(offset + bytes_written);
+
+ errno = 0;
+ int rv = ptrace (PT_IO, pid, &io, 0);
+ if (rv == -1)
+ {
+ gdb_assert (errno != 0);
+ return errno;
+ }
+ if (io.piod_len == 0)
+ return 0;
+
+ bytes_written += io.piod_len;
+ io.piod_len = len - bytes_written;
+ }
+ while (bytes_written < len);
+ }
+
+ if (xfered_len)
+ *xfered_len = bytes_written;
+
+ return 0;
+}
+
+/* See netbsd-nat.h. */
+
+int
+read_memory (pid_t pid, unsigned char *readbuf, CORE_ADDR offset,
+ size_t len, size_t *xfered_len)
+{
+ struct ptrace_io_desc io;
+ io.piod_op = PIOD_READ_D;
+ io.piod_len = len;
+
+ size_t bytes_read = 0;
+
+ /* Zero length write always succeeds. */
+ if (len > 0)
+ {
+ do
+ {
+ io.piod_offs = (void *)(offset + bytes_read);
+ io.piod_addr = readbuf + bytes_read;
+
+ int rv = ptrace (PT_IO, pid, &io, 0);
+ if (rv == -1)
+ return errno;
+ if (io.piod_len == 0)
+ return 0;
+
+ bytes_read += io.piod_len;
+ io.piod_len = len - bytes_read;
+ }
+ while (bytes_read < len);
+ }
+
+ if (xfered_len)
+ *xfered_len = bytes_read;
+
+ return 0;
+}
+
}
diff --git a/gdb/nat/netbsd-nat.h b/gdb/nat/netbsd-nat.h
index d77119bb862..594dec1ba48 100644
--- a/gdb/nat/netbsd-nat.h
+++ b/gdb/nat/netbsd-nat.h
@@ -67,6 +67,28 @@ extern void enable_proc_events (pid_t pid);
extern int qxfer_siginfo (pid_t pid, const char *annex, unsigned char *readbuf,
unsigned const char *writebuf, CORE_ADDR offset,
int len);
+
+/* Write gdb's LEN bytes from WRITEBUF and copy it to OFFSET in inferior
+ process' address space. The inferior is specified by PID.
+ Returns 0 on success or errno on failure and the number of bytes
+ on a successful transfer in XFERED_LEN.
+
+ This function assumes internally that the queried process is stopped and
+ traced. */
+
+extern int write_memory (pid_t pid, unsigned const char *writebuf,
+ CORE_ADDR offset, size_t len, size_t *xfered_len);
+
+/* Read inferior process's LEN bytes from OFFSET and copy it to WRITEBUF in
+ gdb's address space.
+ Returns 0 on success or errno on failure and the number of bytes
+ on a successful transfer in XFERED_LEN.
+
+ This function assumes internally that the queried process is stopped and
+ traced. */
+
+extern int read_memory (pid_t pid, unsigned char *readbuf, CORE_ADDR offset,
+ size_t len, size_t *xfered_len);
}
#endif
diff --git a/gdb/nbsd-nat.c b/gdb/nbsd-nat.c
index 7a07fbf6d8a..46dcfac2cf6 100644
--- a/gdb/nbsd-nat.c
+++ b/gdb/nbsd-nat.c
@@ -764,6 +764,29 @@ nbsd_nat_target::xfer_partial (enum target_object object,
*xfered_len = len;
return TARGET_XFER_OK;
}
+ case TARGET_OBJECT_MEMORY:
+ {
+ size_t xfered;
+ int res;
+ if (writebuf != nullptr)
+ res = netbsd_nat::write_memory (pid, writebuf, offset, len, &xfered);
+ else
+ res = netbsd_nat::read_memory (pid, readbuf, offset, len, &xfered);
+ if (res != 0)
+ {
+ if (res == EACCES)
+ fprintf_unfiltered (gdb_stderr, "Cannot %s process at %s (%s). "
+ "Is PaX MPROTECT active? See security(7), "
+ "sysctl(7), paxctl(8)\n",
+ (writebuf ? "write to" : "read from"),
+ pulongest (offset), safe_strerror (errno));
+ return TARGET_XFER_E_IO;
+ }
+ if (xfered == 0)
+ return TARGET_XFER_EOF;
+ *xfered_len = (ULONGEST) xfered;
+ return TARGET_XFER_OK;
+ }
default:
return inf_ptrace_target::xfer_partial (object, annex,
readbuf, writebuf, offset,
diff --git a/gdbserver/ChangeLog b/gdbserver/ChangeLog
index d4e8e52c74e..305cb0f4a2b 100644
--- a/gdbserver/ChangeLog
+++ b/gdbserver/ChangeLog
@@ -1,3 +1,8 @@
+2020-10-07 Kamil Rytarowski <n54@gmx.com>
+
+ * netbsd-low.cc (netbsd_process_target::read_memory)
+ (netbsd_process_target::write_memory): Update.
+
2020-10-06 Shahab Vahedi <shahab@synopsys.com>
* regcache.cc (register_data): Remove unused "fetch" argument.
diff --git a/gdbserver/netbsd-low.cc b/gdbserver/netbsd-low.cc
index 7bec55a56ac..e5ea8233e00 100644
--- a/gdbserver/netbsd-low.cc
+++ b/gdbserver/netbsd-low.cc
@@ -556,36 +556,8 @@ int
netbsd_process_target::read_memory (CORE_ADDR memaddr, unsigned char *myaddr,
int size)
{
- struct ptrace_io_desc io;
- io.piod_op = PIOD_READ_D;
- io.piod_len = size;
-
pid_t pid = current_process ()->pid;
-
- int bytes_read = 0;
-
- if (size == 0)
- {
- /* Zero length write always succeeds. */
- return 0;
- }
- do
- {
- io.piod_offs = (void *)(memaddr + bytes_read);
- io.piod_addr = myaddr + bytes_read;
-
- int rv = ptrace (PT_IO, pid, &io, 0);
- if (rv == -1)
- return errno;
- if (io.piod_len == 0)
- return 0;
-
- bytes_read += io.piod_len;
- io.piod_len = size - bytes_read;
- }
- while (bytes_read < size);
-
- return 0;
+ return netbsd_nat::read_memory (pid, myaddr, memaddr, size, nullptr);
}
/* Implement the write_memory target_ops method. */
@@ -594,37 +566,8 @@ int
netbsd_process_target::write_memory (CORE_ADDR memaddr,
const unsigned char *myaddr, int size)
{
- struct ptrace_io_desc io;
- io.piod_op = PIOD_WRITE_D;
- io.piod_len = size;
-
pid_t pid = current_process ()->pid;
-
- int bytes_written = 0;
-
- if (size == 0)
- {
- /* Zero length write always succeeds. */
- return 0;
- }
-
- do
- {
- io.piod_addr = (void *)(myaddr + bytes_written);
- io.piod_offs = (void *)(memaddr + bytes_written);
-
- int rv = ptrace (PT_IO, pid, &io, 0);
- if (rv == -1)
- return errno;
- if (io.piod_len == 0)
- return 0;
-
- bytes_written += io.piod_len;
- io.piod_len = size - bytes_written;
- }
- while (bytes_written < size);
-
- return 0;
+ return netbsd_nat::write_memory (pid, myaddr, memaddr, size, nullptr);
}
/* Implement the request_interrupt target_ops method. */
--
2.28.0
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