[PATCH 3/4] [nto] Fix nto target stopped by watchpoint.

Aleksandar Ristovski
2015-10-13T16:01:33Z

Fix stopped by watchpoint detection: add inferior data, use inferior data
for storing last stopped flags needed for detection.
Add binary sniffing for QNX osabi.

* nto-procfs.c (procfs_wait): Set stopped_flags.
(procfs_stopped_by_watchpoint): Use flags stored in inferior data.
* nto-tdep.c (QNX_NOTE_NAME, QNX_INFO_SECT_NAME): New defines.
(nto_inferior_data_reg): New definition.
(nto_sniff_abi_note_section): New function.
(nto_elf_osabi_sniffer): Use nto_sniff_abi_note_section.
(nto_new_inferior_data, nto_inferior_data_cleanup, nto_inferior_data):
New functions.
(_initialize_nto_tdep): New forward declaration, new function.
* nto-tdep.h (nto_inferior_data): New struct.
(nto_inferior_data): New function declaration.
---
gdb/ChangeLog | 14 +++++++++
gdb/nto-procfs.c | 21 ++++++++++++-
gdb/nto-tdep.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
gdb/nto-tdep.h | 12 ++++++++
4 files changed, 133 insertions(+), 4 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 04c9f0a..1aa8a68 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,17 @@
+<2015-3> Aleksandar Ristovski <aristovski@qnx.com>
+
+ * nto-procfs.c (procfs_wait): Set stopped_flags.
+ (procfs_stopped_by_watchpoint): Use flags stored in inferior data.
+ * nto-tdep.c (QNX_NOTE_NAME, QNX_INFO_SECT_NAME): New defines.
+ (nto_inferior_data_reg): New definition.
+ (nto_sniff_abi_note_section): New function.
+ (nto_elf_osabi_sniffer): Use nto_sniff_abi_note_section.
+ (nto_new_inferior_data, nto_inferior_data_cleanup, nto_inferior_data):
+ New functions.
+ (_initialize_nto_tdep): New forward declaration, new function.
+ * nto-tdep.h (nto_inferior_data): New struct.
+ (nto_inferior_data): New function declaration.
+
<2015-2> Aleksandar Ristovski <aristovski@qnx.com>

* nto-procfs.c (sys/auxv.h): Include.
diff --git a/gdb/nto-procfs.c b/gdb/nto-procfs.c
index a4b5ce8..ae7329c 100644
--- a/gdb/nto-procfs.c
+++ b/gdb/nto-procfs.c
@@ -786,6 +786,9 @@ procfs_wait (struct target_ops *ops,
devctl (ctl_fd, DCMD_PROC_STATUS, &status, sizeof (status), 0);
}

+ nto_inferior_data (NULL)->stopped_flags = status.flags;
+ nto_inferior_data (NULL)->stopped_pc = status.ip;
+
if (status.flags & _DEBUG_FLAG_SSTEP)
{
ourstatus->kind = TARGET_WAITKIND_STOPPED;
@@ -1630,5 +1633,21 @@ procfs_insert_hw_watchpoint (struct target_ops *self,
static int
procfs_stopped_by_watchpoint (struct target_ops *ops)
{
- return 0;
+ /* NOTE: nto_stopped_by_watchpoint will be called ONLY while we are
+ stopped due to a SIGTRAP. This assumes gdb works in 'all-stop' mode;
+ future gdb versions will likely run in 'non-stop' mode in which case
+ we will have to store/examine statuses per thread in question.
+ Until then, this will work fine. */
+
+ struct inferior *inf = current_inferior ();
+ struct nto_inferior_data *inf_data;
+
+ gdb_assert (inf != NULL);
+
+ inf_data = nto_inferior_data (inf);
+
+ return inf_data->stopped_flags
+ & (_DEBUG_FLAG_TRACE_RD
+ | _DEBUG_FLAG_TRACE_WR
+ | _DEBUG_FLAG_TRACE_MODIFY);
}
diff --git a/gdb/nto-tdep.c b/gdb/nto-tdep.c
index 63094e8..62dbf8b 100644
--- a/gdb/nto-tdep.c
+++ b/gdb/nto-tdep.c
@@ -33,6 +33,9 @@
#include "objfiles.h"
#include "symfile.h"

+#define QNX_NOTE_NAME "QNX"
+#define QNX_INFO_SECT_NAME "QNX_info"
+
#ifdef __CYGWIN__
#include <sys/cygwin.h>
#endif
@@ -47,6 +50,8 @@ static char default_nto_target[] = "";

struct nto_target_ops current_nto_target;

+static const struct inferior_data *nto_inferior_data_reg;
+
static char *
nto_target (void)
{
@@ -331,12 +336,51 @@ nto_dummy_supply_regset (struct regcache *regcache, char *regs)
/* Do nothing. */
}

+static void
+nto_sniff_abi_note_section (bfd *abfd, asection *sect, void *obj)
+{
+ const char *sectname;
+ unsigned int sectsize;
+ char *note; // buffer holding the section contents
+ unsigned int namelen;
+ const char *name;
+
+ sectname = bfd_get_section_name (abfd, sect);
+ sectsize = bfd_section_size (abfd, sect);
+
+ /* TODO: limit the note size here, for now limit is 128 bytes
+ (enough to check the name and type). */
+ if (sectsize > 128)
+ sectsize = 128;
+
+ if (sectname && strstr (sectname, QNX_INFO_SECT_NAME) != NULL)
+ *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
+
+ if (sectname && strstr (sectname, "note") != NULL)
+ {
+ note = alloca (sectsize);
+ bfd_get_section_contents (abfd, sect, note, 0, sectsize);
+ namelen = (unsigned int) bfd_h_get_32 (abfd, note);
+ name = note + 12;
+
+ if (namelen > 0
+ && (0 == strcmp (name, QNX_NOTE_NAME)))
+ *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
+ }
+}
+
enum gdb_osabi
nto_elf_osabi_sniffer (bfd *abfd)
{
- if (nto_is_nto_target)
+ enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
+
+ bfd_map_over_sections (abfd,
+ nto_sniff_abi_note_section,
+ &osabi);
+
+ if (osabi == GDB_OSABI_UNKNOWN && nto_is_nto_target)
return nto_is_nto_target (abfd);
- return GDB_OSABI_UNKNOWN;
+ return osabi;
}

static const char *nto_thread_state_str[] =
@@ -396,7 +440,6 @@ nto_initialize_signals (void)
#endif
}

-
/* Read AUXV from initial_stack. */
LONGEST
nto_read_auxv_from_initial_stack (CORE_ADDR initial_stack, gdb_byte *readbuf,
@@ -480,4 +523,45 @@ nto_read_auxv_from_initial_stack (CORE_ADDR initial_stack, gdb_byte *readbuf,
return len_read;
}

+static struct nto_inferior_data *
+nto_new_inferior_data (void)
+{
+ struct nto_inferior_data *const inf_data
+ = XCNEW (struct nto_inferior_data);
+
+ return inf_data;
+}
+
+static void
+nto_inferior_data_cleanup (struct inferior *const inf, void *const dat)
+{
+ xfree (dat);
+}
+
+struct nto_inferior_data *
+nto_inferior_data (struct inferior *const inferior)
+{
+ struct inferior *const inf = inferior ? inferior : current_inferior ();
+ struct nto_inferior_data *inf_data;
+
+ gdb_assert (inf != NULL);
+
+ inf_data = inferior_data (inf, nto_inferior_data_reg);
+ if (inf_data == NULL)
+ {
+ set_inferior_data (inf, nto_inferior_data_reg,
+ (inf_data = nto_new_inferior_data ()));
+ }
+
+ return inf_data;
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes. */
+extern initialize_file_ftype _initialize_nto_tdep;

+void
+_initialize_nto_tdep (void)
+{
+ nto_inferior_data_reg
+ = register_inferior_data_with_cleanup (NULL, nto_inferior_data_cleanup);
+}
diff --git a/gdb/nto-tdep.h b/gdb/nto-tdep.h
index 7089a12..6ed9da0 100644
--- a/gdb/nto-tdep.h
+++ b/gdb/nto-tdep.h
@@ -142,6 +142,16 @@ struct private_thread_info
char name[1];
};

+/* Per-inferior data, common for both procfs and remote. */
+struct nto_inferior_data
+{
+ /* Last stopped flags result from wait function */
+ unsigned int stopped_flags;
+
+ /* Last known stopped PC */
+ CORE_ADDR stopped_pc;
+};
+
/* Generic functions in nto-tdep.c. */

void nto_init_solib_absolute_prefix (void);
@@ -172,4 +182,6 @@ LONGEST nto_read_auxv_from_initial_stack (CORE_ADDR inital_stack,
gdb_byte *readbuf,
LONGEST len, size_t sizeof_auxv_t);

+struct nto_inferior_data *nto_inferior_data (struct inferior *inf);
+
#endif
--
1.9.1