From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
From: Keith Seitz <keiths@redhat.com>
Date: Mon, 27 Jul 2020 16:52:18 -0400
Subject: gdb-rhbz1842691-corefile-mem-access-3of15.patch
;; section_table_xfer_memory: Replace section name with callback predicate
;; Kevin Buettner, RH BZ 1842691
Author: Kevin Buettner <kevinb@redhat.com>
Date: Wed Mar 4 17:42:41 2020 -0700
section_table_xfer_memory: Replace section name with callback predicate
This patch is motivated by the need to be able to select sections
that section_table_xfer_memory_partial should consider for memory
transfers. I'll use this facility in the next patch in this series.
section_table_xfer_memory_partial() can currently be passed a section
name which may be used to make name-based selections. This is similar
to what I want to do, except that I want to be able to consider
section flags instead of the name.
I'm replacing the section name parameter with a predicate that,
when passed a pointer to a target_section struct, will return
true if that section should be further considered, or false which
indicates that it shouldn't.
I've converted the one existing use where a non-NULL section
name is passed to section_table_xfer_memory_partial(). Instead
of passing the section name, it now looks like this:
auto match_cb = [=] (const struct target_section *s)
{
return (strcmp (section_name, s->the_bfd_section->name) == 0);
};
return section_table_xfer_memory_partial (readbuf, writebuf,
memaddr, len, xfered_len,
table->sections,
table->sections_end,
match_cb);
The other callers all passed NULL; they've been simplified somewhat
in that they no longer need to pass NULL.
gdb/ChangeLog:
* exec.h (section_table_xfer_memory): Revise declaration,
replacing section name parameter with an optional callback
predicate.
* exec.c (section_table_xfer_memory): Likewise.
* bfd-target.c, exec.c, target.c, corelow.c: Adjust all callers
of section_table_xfer_memory.
diff --git a/gdb/bfd-target.c b/gdb/bfd-target.c
--- a/gdb/bfd-target.c
+++ b/gdb/bfd-target.c
@@ -77,8 +77,7 @@ target_bfd::xfer_partial (target_object object,
return section_table_xfer_memory_partial (readbuf, writebuf,
offset, len, xfered_len,
m_table.sections,
- m_table.sections_end,
- NULL);
+ m_table.sections_end);
}
default:
return TARGET_XFER_E_IO;
diff --git a/gdb/corelow.c b/gdb/corelow.c
--- a/gdb/corelow.c
+++ b/gdb/corelow.c
@@ -758,8 +758,7 @@ core_target::xfer_partial (enum target_object object, const char *annex,
(readbuf, writebuf,
offset, len, xfered_len,
m_core_section_table.sections,
- m_core_section_table.sections_end,
- NULL));
+ m_core_section_table.sections_end));
case TARGET_OBJECT_AUXV:
if (readbuf)
diff --git a/gdb/exec.c b/gdb/exec.c
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -792,7 +792,8 @@ section_table_xfer_memory_partial (gdb_byte *readbuf, const gdb_byte *writebuf,
ULONGEST *xfered_len,
struct target_section *sections,
struct target_section *sections_end,
- const char *section_name)
+ gdb::function_view<bool
+ (const struct target_section *)> match_cb)
{
int res;
struct target_section *p;
@@ -808,7 +809,7 @@ section_table_xfer_memory_partial (gdb_byte *readbuf, const gdb_byte *writebuf,
struct bfd_section *asect = p->the_bfd_section;
bfd *abfd = asect->owner;
- if (section_name && strcmp (section_name, asect->name) != 0)
+ if (match_cb != nullptr && !match_cb (p))
continue; /* not the section we need. */
if (memaddr >= p->addr)
{
@@ -881,8 +882,7 @@ exec_target::xfer_partial (enum target_object object,
return section_table_xfer_memory_partial (readbuf, writebuf,
offset, len, xfered_len,
table->sections,
- table->sections_end,
- NULL);
+ table->sections_end);
else
return TARGET_XFER_E_IO;
}
diff --git a/gdb/exec.h b/gdb/exec.h
--- a/gdb/exec.h
+++ b/gdb/exec.h
@@ -58,8 +58,13 @@ extern enum target_xfer_status
Request to transfer up to LEN 8-bit bytes of the target sections
defined by SECTIONS and SECTIONS_END. The OFFSET specifies the
starting address.
- If SECTION_NAME is not NULL, only access sections with that same
- name.
+
+ The MATCH_CB predicate is optional; when provided it will be called
+ for each section under consideration. When MATCH_CB evaluates as
+ true, the section remains under consideration; a false result
+ removes it from consideration for performing the memory transfers
+ noted above. See memory_xfer_partial_1() in target.c for an
+ example.
Return the number of bytes actually transfered, or zero when no
data is available for the requested range.
@@ -76,7 +81,9 @@ extern enum target_xfer_status
ULONGEST, ULONGEST, ULONGEST *,
struct target_section *,
struct target_section *,
- const char *);
+ gdb::function_view<bool
+ (const struct target_section *)> match_cb
+ = nullptr);
/* Read from mappable read-only sections of BFD executable files.
Similar to exec_read_partial_read_only, but return
diff --git a/gdb/target.c b/gdb/target.c
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -1022,11 +1022,17 @@ memory_xfer_partial_1 (struct target_ops *ops, enum target_object object,
const char *section_name = section->the_bfd_section->name;
memaddr = overlay_mapped_address (memaddr, section);
+
+ auto match_cb = [=] (const struct target_section *s)
+ {
+ return (strcmp (section_name, s->the_bfd_section->name) == 0);
+ };
+
return section_table_xfer_memory_partial (readbuf, writebuf,
memaddr, len, xfered_len,
table->sections,
table->sections_end,
- section_name);
+ match_cb);
}
}
@@ -1044,8 +1050,7 @@ memory_xfer_partial_1 (struct target_ops *ops, enum target_object object,
return section_table_xfer_memory_partial (readbuf, writebuf,
memaddr, len, xfered_len,
table->sections,
- table->sections_end,
- NULL);
+ table->sections_end);
}
}