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Re: [PATCH] refreshed patch for PR 11804 and PR 9904
Hi Jan,
On Sat, 28 Jul 2012, Jan Kratochvil wrote:
> 7.4.1 is too old.
Here is a patch against a fresh checkout from the git mirror.
> Primarily linux_nat_find_memory_regions is now reworked and renamed as
> linux_find_memory_regions as GDB can now gcore also from remotely run process
> via gdbserver. The testcase should be verified it also works with gdbserver
> afterwards, see gdb/testsuite/boards/native-gdbserver.exp.
I only tested the added test case:
make -C gdb/testsuite/ check RUNTESTFLAGS="gdb.base/gcore-relro.exp"
make -C gdb/testsuite/ check RUNTESTFLAGS="--target_board=native-gdbserver
gdb.base/gcore-relro.exp"
> Also there should be descriptive comments before each modified function.
> I can write those otherwise.
I'm not sure what kind you expect, so I'll let you write them. :-)
> Here is missing a check:
> if (separate_debug_objfile_backlink != NULL)
> continue;
> as separate debug info files (in /usr/lib/debug, sometimes with .debug
> extension) are irrelevant for gcore.
Should be good now.
> Therefore if "Anonymous:" entry is not present at all (=not supported by
> Linux kernel on that host) we must write out very every area as we have
> no way to verify for swap-cached pages (having Anonymous > 0).
>
> Sure if "Anonymous:" is present and it is > 0 it also must be written
> out.
Ditto.
> You can reproduce the "Anonymous:" problem with
> http://people.redhat.com/jkratoch/relroswap.c
> although it is not suitable for GDB testsuite as it needs to do huge memory
> allocations to swap out (+swap in) the testcase pages.
> (If you have a better idea how to make "Anonymous:" entry non-zero it is sure
> welcome. I have tried madvise (MADV_DONTNEED) but it does not work.)
Starting the test makes my desktop unusable (no SSD for swap yet), so I
cowardly gave up.
> > +set testfile "gcore-relro"
>
> Is hould use 'standard_testfile' like other testcases recently modified
> by Tom Tromey.
I hope that's ok now.
Cheers,
Jean-Marc
--
saffroy@gmail.com
diff --git a/gdb/defs.h b/gdb/defs.h
index 7be99a2..feb3106 100644
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -362,9 +362,10 @@ extern void init_source_path (void);
/* From exec.c */
+/* MODIFIED has value -1 for unknown, 0 for not modified, 1 for modified. */
typedef int (*find_memory_region_ftype) (CORE_ADDR addr, unsigned long size,
int read, int write, int exec,
- void *data);
+ int modified, void *data);
/* Take over the 'find_mapped_memory' vector from exec.c. */
extern void exec_set_find_memory_regions
diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index b3e4fab..5db0f5d 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -132,7 +132,7 @@ fbsd_find_memory_regions (find_memory_region_ftype func, void *obfd)
}
/* Invoke the callback function to create the corefile segment. */
- func (start, size, read, write, exec, obfd);
+ func (start, size, read, write, exec, -1, obfd);
}
do_cleanups (cleanup);
diff --git a/gdb/gcore.c b/gdb/gcore.c
index a45e787..a9dd2ba 100644
--- a/gdb/gcore.c
+++ b/gdb/gcore.c
@@ -380,8 +380,8 @@ make_output_phdrs (bfd *obfd, asection *osec, void *ignored)
}
static int
-gcore_create_callback (CORE_ADDR vaddr, unsigned long size,
- int read, int write, int exec, void *data)
+gcore_create_callback (CORE_ADDR vaddr, unsigned long size, int read,
+ int write, int exec, int modified, void *data)
{
bfd *obfd = data;
asection *osec;
@@ -390,7 +390,7 @@ gcore_create_callback (CORE_ADDR vaddr, unsigned long size,
/* If the memory segment has no permissions set, ignore it, otherwise
when we later try to access it for read/write, we'll get an error
or jam the kernel. */
- if (read == 0 && write == 0 && exec == 0)
+ if (read == 0 && write == 0 && exec == 0 && modified == 0)
{
if (info_verbose)
{
@@ -401,7 +401,7 @@ gcore_create_callback (CORE_ADDR vaddr, unsigned long size,
return 0;
}
- if (write == 0 && !solib_keep_data_in_core (vaddr, size))
+ if (write == 0 && modified == 0 && !solib_keep_data_in_core (vaddr, size))
{
/* See if this region of memory lies inside a known file on disk.
If so, we can avoid copying its contents by clearing SEC_LOAD. */
@@ -433,10 +433,12 @@ gcore_create_callback (CORE_ADDR vaddr, unsigned long size,
}
}
- keep:
- flags |= SEC_READONLY;
+ keep:;
}
+ if (write == 0)
+ flags |= SEC_READONLY;
+
if (exec)
flags |= SEC_CODE;
else
@@ -477,6 +479,10 @@ objfile_find_memory_regions (find_memory_region_ftype func, void *obfd)
asection *isec = objsec->the_bfd_section;
flagword flags = bfd_get_section_flags (ibfd, isec);
+ /* Separate debug info files are irrelevant for gcore. */
+ if (objfile->separate_debug_objfile_backlink != NULL)
+ continue;
+
if ((flags & SEC_ALLOC) || (flags & SEC_LOAD))
{
int size = bfd_section_size (ibfd, isec);
@@ -486,6 +492,7 @@ objfile_find_memory_regions (find_memory_region_ftype func, void *obfd)
1, /* All sections will be readable. */
(flags & SEC_READONLY) == 0, /* Writable. */
(flags & SEC_CODE) != 0, /* Executable. */
+ -1, /* Modified is unknown. */
obfd);
if (ret != 0)
return ret;
@@ -498,6 +505,7 @@ objfile_find_memory_regions (find_memory_region_ftype func, void *obfd)
1, /* Stack section will be readable. */
1, /* Stack section will be writable. */
0, /* Stack section will not be executable. */
+ 1, /* Stack section will be modified. */
obfd);
/* Make a heap segment. */
@@ -506,6 +514,7 @@ objfile_find_memory_regions (find_memory_region_ftype func, void *obfd)
1, /* Heap section will be readable. */
1, /* Heap section will be writable. */
0, /* Heap section will not be executable. */
+ 1, /* Heap section will be modified. */
obfd);
return 0;
diff --git a/gdb/gnu-nat.c b/gdb/gnu-nat.c
index 0c45f20..046e32a 100644
--- a/gdb/gnu-nat.c
+++ b/gdb/gnu-nat.c
@@ -2558,7 +2558,7 @@ gnu_find_memory_regions (find_memory_region_ftype func, void *data)
last_protection & VM_PROT_READ,
last_protection & VM_PROT_WRITE,
last_protection & VM_PROT_EXECUTE,
- data);
+ -1, data);
last_region_address = region_address;
last_region_end = region_address += region_length;
last_protection = protection;
@@ -2571,7 +2571,7 @@ gnu_find_memory_regions (find_memory_region_ftype func, void *data)
last_protection & VM_PROT_READ,
last_protection & VM_PROT_WRITE,
last_protection & VM_PROT_EXECUTE,
- data);
+ -1, data);
return 0;
}
diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index b6f2efb..4a36fe4 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -547,19 +547,27 @@ linux_find_memory_regions (struct gdbarch *gdbarch,
return 1;
xsnprintf (filename, sizeof filename,
- "/proc/%d/maps", current_inferior ()->pid);
+ "/proc/%d/smaps", current_inferior ()->pid);
data = target_fileio_read_stralloc (filename);
+ if (! data)
+ {
+ xsnprintf (filename, sizeof filename,
+ "/proc/%d/maps", current_inferior ()->pid);
+ data = target_fileio_read_stralloc (filename);
+ }
if (data)
{
struct cleanup *cleanup = make_cleanup (xfree, data);
char *line;
- for (line = strtok (data, "\n"); line; line = strtok (NULL, "\n"))
+ line = strtok (data, "\n");
+ while (line)
{
ULONGEST addr, endaddr, offset, inode;
const char *permissions, *device, *filename;
size_t permissions_len, device_len;
int read, write, exec;
+ int modified = 0, has_anonymous = 0;
read_mapping (line, &addr, &endaddr, &permissions, &permissions_len,
&offset, &device, &device_len, &inode, &filename);
@@ -569,8 +577,34 @@ linux_find_memory_regions (struct gdbarch *gdbarch,
write = (memchr (permissions, 'w', permissions_len) != 0);
exec = (memchr (permissions, 'x', permissions_len) != 0);
+ /* Try to detect if region was modified by parsing smaps counters. */
+ for (line = strtok (NULL, "\n");
+ line && line[0] >= 'A' && line[0] <= 'Z';
+ line = strtok (NULL, "\n"))
+ {
+ char keyword[64 + 1];
+ unsigned long number;
+
+ if (sscanf(line, "%64s%lu kB\n", keyword, &number) != 2)
+ {
+ warning (_("Error parsing {s,}maps file '%s'"), filename);
+ break;
+ }
+ if (strcmp(keyword, "Anonymous:") == 0)
+ has_anonymous = 1;
+ if (number != 0 && (strcmp (keyword, "Shared_Dirty:") == 0
+ || strcmp (keyword, "Private_Dirty:") == 0
+ || strcmp (keyword, "Swap:") == 0
+ || strcmp (keyword, "Anonymous:") == 0))
+ modified = 1;
+ }
+
+ /* When "Anonymous:" is missing, we can't be sure. */
+ if (! has_anonymous && modified == 0)
+ modified = -1;
+
/* Invoke the callback function to create the corefile segment. */
- func (addr, endaddr - addr, read, write, exec, obfd);
+ func (addr, endaddr - addr, read, write, exec, modified, obfd);
}
do_cleanups (cleanup);
diff --git a/gdb/procfs.c b/gdb/procfs.c
index 4409e5b..79f22de 100644
--- a/gdb/procfs.c
+++ b/gdb/procfs.c
@@ -5074,7 +5074,7 @@ find_memory_regions_callback (struct prmap *map,
(map->pr_mflags & MA_READ) != 0,
(map->pr_mflags & MA_WRITE) != 0,
(map->pr_mflags & MA_EXEC) != 0,
- data);
+ -1, data);
}
/* External interface. Calls a callback function once for each
diff --git a/gdb/testsuite/gdb.base/gcore-relro-lib.c b/gdb/testsuite/gdb.base/gcore-relro-lib.c
new file mode 100644
index 0000000..d74b690
--- /dev/null
+++ b/gdb/testsuite/gdb.base/gcore-relro-lib.c
@@ -0,0 +1,21 @@
+/* Copyright 2010 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+void
+lib (void)
+{
+}
diff --git a/gdb/testsuite/gdb.base/gcore-relro-main.c b/gdb/testsuite/gdb.base/gcore-relro-main.c
new file mode 100644
index 0000000..46b9dfe
--- /dev/null
+++ b/gdb/testsuite/gdb.base/gcore-relro-main.c
@@ -0,0 +1,25 @@
+/* Copyright 2010 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+extern void lib (void);
+
+int
+main (void)
+{
+ lib ();
+ return 0;
+}
diff --git a/gdb/testsuite/gdb.base/gcore-relro.exp b/gdb/testsuite/gdb.base/gcore-relro.exp
new file mode 100644
index 0000000..ace80e4
--- /dev/null
+++ b/gdb/testsuite/gdb.base/gcore-relro.exp
@@ -0,0 +1,78 @@
+# Copyright 2012 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+if {[skip_shlib_tests]} {
+ return 0
+}
+
+standard_testfile gcore-relro-main.c
+set libfile gcore-relro-lib
+set srcfile_lib ${libfile}.c
+set binfile_lib [standard_output_file ${libfile}.so]
+set gcorefile ${binfile}.gcore
+set objfile [standard_output_file ${testfile}.o]
+
+ if { [gdb_compile_shlib ${srcdir}/${subdir}/${srcfile_lib} ${binfile_lib} {debug}] != ""
+ || [gdb_compile ${srcdir}/${subdir}/${srcfile} ${objfile} object {debug}] != "" } {
+ untested ${testfile}.exp
+ return -1
+ }
+ set opts [list debug shlib=${binfile_lib} additional_flags=-Wl,-z,relro]
+ if { [gdb_compile ${objfile} ${binfile} executable $opts] != "" } {
+ unsupported "-Wl,-z,relro compilation failed"
+ return -1
+ }
+
+clean_restart ${binfile}
+gdb_load_shlibs ${binfile_lib}
+
+# Does this gdb support gcore?
+set test "help gcore"
+gdb_test_multiple $test $test {
+ -re "Undefined command: .gcore.*\r\n$gdb_prompt $" {
+ # gcore command not supported -- nothing to test here.
+ unsupported "gdb does not support gcore on this target"
+ return -1;
+ }
+ -re "Save a core file .*\r\n$gdb_prompt $" {
+ pass $test
+ }
+}
+
+if { ![runto lib] } then {
+ return -1
+}
+
+set escapedfilename [string_to_regexp ${gcorefile}]
+
+set test "save a corefile"
+gdb_test_multiple "gcore ${gcorefile}" $test {
+ -re "Saved corefile ${escapedfilename}\r\n$gdb_prompt $" {
+ pass $test
+ }
+ -re "Can't create a corefile\r\n$gdb_prompt $" {
+ unsupported $test
+ return -1
+ }
+}
+
+# Now restart gdb and load the corefile.
+
+clean_restart ${binfile}
+gdb_load_shlibs ${binfile_lib}
+
+gdb_test "core ${gcorefile}" "Core was generated by .*" "re-load generated corefile"
+
+gdb_test "frame" "#0 \[^\r\n\]* lib .*" "library got loaded"