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[PATCH] refreshed patch for PR 11804 and PR 9904
- From: Jean-Marc Saffroy <saffroy at gmail dot com>
- To: gdb-patches at sources dot redhat dot com
- Date: Wed, 18 Jul 2012 02:50:08 +0200 (CEST)
- Subject: [PATCH] refreshed patch for PR 11804 and PR 9904
Hi,
I just found out that gcore has been broken with some Linux kernels for a
while (observed with some 3.2 kernels on Ubuntu, but not on a vanilla
2.6.36 on another box), and this led me there:
http://sourceware.org/bugzilla/show_bug.cgi?id=9904
http://sourceware.org/bugzilla/show_bug.cgi?id=11804
In particular, 11804 has an interesting discussion of the problem, and a
very nice patch, which I've refreshed for gdb 7.4.1. So here it is, if
anyone else needs it: it fixes gcore for my case, but I didn't check the
test suite bits.
It would be nice to see this finally landed in gdb!
Cheers,
Jean-Marc Saffroy
--
saffroy@gmail.com
diff --git a/gdb/defs.h b/gdb/defs.h
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -672,9 +672,10 @@ 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
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -132,7 +132,7 @@ fbsd_find_memory_regions (find_memory_re
}
/* 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
--- a/gdb/gcore.c
+++ b/gdb/gcore.c
@@ -377,8 +377,8 @@ make_output_phdrs (bfd *obfd, asection *
}
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;
@@ -387,7 +387,7 @@ gcore_create_callback (CORE_ADDR vaddr,
/* 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)
{
@@ -398,7 +398,7 @@ gcore_create_callback (CORE_ADDR vaddr,
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. */
@@ -430,10 +430,12 @@ gcore_create_callback (CORE_ADDR vaddr,
}
}
- keep:
- flags |= SEC_READONLY;
+ keep:;
}
+ if (write == 0)
+ flags |= SEC_READONLY;
+
if (exec)
flags |= SEC_CODE;
else
@@ -483,6 +485,7 @@ objfile_find_memory_regions (find_memory
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;
@@ -495,6 +498,7 @@ objfile_find_memory_regions (find_memory
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. */
@@ -503,6 +507,7 @@ objfile_find_memory_regions (find_memory
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
--- a/gdb/gnu-nat.c
+++ b/gdb/gnu-nat.c
@@ -2558,7 +2558,7 @@ gnu_find_memory_regions (find_memory_reg
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_reg
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-nat.c b/gdb/linux-nat.c
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -4352,7 +4352,7 @@ read_mapping (FILE *mapfile,
long long *endaddr,
char *permissions,
long long *offset,
- char *device, long long *inode, char *filename)
+ char *device, long long *inode, char *filename, int *modified)
{
int ret = fscanf (mapfile, "%llx-%llx %s %llx %s %llx",
addr, endaddr, permissions, offset, device, inode);
@@ -4370,6 +4370,40 @@ read_mapping (FILE *mapfile,
ret += fscanf (mapfile, "%[^\n]\n", filename);
}
+ if (modified != NULL)
+ {
+ *modified = -1;
+ for (;;)
+ {
+ int ch;
+ char keyword[64 + 1];
+ unsigned long number;
+
+ ch = fgetc (mapfile);
+ if (ch != EOF)
+ ungetc (ch, mapfile);
+ if (ch < 'A' || ch > 'Z')
+ break;
+ if (fscanf (mapfile, "%64s%lu kB\n", keyword, &number) != 2)
+ {
+ warning (_("Error parsing /proc/PID/{s,}maps file"));
+ do
+ ch = fgetc (mapfile);
+ while (ch != EOF && ch != '\n');
+ break;
+ }
+ if (number != 0 && (strcmp (keyword, "Shared_Dirty:") == 0
+ || strcmp (keyword, "Private_Dirty:") == 0
+ || strcmp (keyword, "Swap:") == 0))
+ *modified = 1;
+ else if (*modified == -1)
+ {
+ /* Valid line proves an smaps file is being read in. */
+ *modified = 0;
+ }
+ }
+ }
+
return (ret != 0 && ret != EOF);
}
@@ -4384,13 +4418,17 @@ linux_nat_find_memory_regions (find_memo
FILE *mapsfile;
long long addr, endaddr, size, offset, inode;
char permissions[8], device[8], filename[MAXPATHLEN];
- int read, write, exec;
+ int read, write, exec, modified;
struct cleanup *cleanup;
/* Compose the filename for the /proc memory map, and open it. */
- sprintf (mapsfilename, "/proc/%d/maps", pid);
+ sprintf (mapsfilename, "/proc/%d/smaps", pid);
if ((mapsfile = fopen (mapsfilename, "r")) == NULL)
- error (_("Could not open %s."), mapsfilename);
+ {
+ sprintf (mapsfilename, "/proc/%d/maps", pid);
+ if ((mapsfile = fopen (mapsfilename, "r")) == NULL)
+ error (_("Could not open %s."), mapsfilename);
+ }
cleanup = make_cleanup_fclose (mapsfile);
if (info_verbose)
@@ -4399,7 +4437,7 @@ linux_nat_find_memory_regions (find_memo
/* Now iterate until end-of-file. */
while (read_mapping (mapsfile, &addr, &endaddr, &permissions[0],
- &offset, &device[0], &inode, &filename[0]))
+ &offset, &device[0], &inode, &filename[0], &modified))
{
size = endaddr - addr;
@@ -4422,7 +4460,7 @@ linux_nat_find_memory_regions (find_memo
/* Invoke the callback function to create the corefile
segment. */
- func (addr, size, read, write, exec, obfd);
+ func (addr, size, read, write, exec, modified, obfd);
}
do_cleanups (cleanup);
return 0;
@@ -4871,7 +4909,8 @@ linux_nat_info_proc_cmd_1 (char *args, e
}
while (read_mapping (procfile, &addr, &endaddr, &permissions[0],
- &offset, &device[0], &inode, &filename[0]))
+ &offset, &device[0], &inode, &filename[0],
+ NULL))
{
size = endaddr - addr;
diff --git a/gdb/procfs.c b/gdb/procfs.c
--- a/gdb/procfs.c
+++ b/gdb/procfs.c
@@ -5275,7 +5275,7 @@ find_memory_regions_callback (struct prm
(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
--- /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
--- /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
--- /dev/null
+++ b/gdb/testsuite/gdb.base/gcore-relro.exp
@@ -0,0 +1,80 @@
+# Copyright 2010 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
+}
+
+set testfile "gcore-relro"
+set srcmainfile ${testfile}-main.c
+set srclibfile ${testfile}-lib.c
+set libfile ${objdir}/${subdir}/${testfile}-lib.so
+set objfile ${objdir}/${subdir}/${testfile}-main.o
+set executable ${testfile}-main
+set binfile ${objdir}/${subdir}/${executable}
+set gcorefile ${objdir}/${subdir}/${executable}.gcore
+
+if { [gdb_compile_shlib ${srcdir}/${subdir}/${srclibfile} ${libfile} {debug}] != ""
+ || [gdb_compile ${srcdir}/${subdir}/${srcmainfile} ${objfile} object {debug}] != "" } {
+ untested ${testfile}.exp
+ return -1
+}
+set opts [list debug shlib=${libfile} additional_flags=-Wl,-z,relro]
+if { [gdb_compile ${objfile} ${binfile} executable $opts] != "" } {
+ unsupported "-Wl,-z,relro compilation failed"
+ return -1
+}
+
+clean_restart $executable
+gdb_load_shlibs $libfile
+
+# 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 $executable
+gdb_load_shlibs $libfile
+
+gdb_test "core ${gcorefile}" "Core was generated by .*" "re-load generated corefile"
+
+gdb_test "frame" "#0 \[^\r\n\]* lib .*" "library got loaded"