[PATCH 2/3] (patch 2/4, v2) [nto] Implement TARGET_OBJECT_AUXV.

Aleksandar Ristovski
2015-10-20T14:28:51Z

gdb/ChangeLog:

* nto-procfs.c (sys/auxv.h): Include.
(procfs_xfer_partial): Implement TARGET_OBJECT_AUXV.
* gdb/nto-tdep.c (nto_read_auxv_from_initial_stack): New function.
* gdb/nto-tdep.h (nto_read_auxv_from_initial_stack): New declaration.
---
gdb/nto-procfs.c | 36 ++++++++++++++++++++++++
gdb/nto-tdep.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
gdb/nto-tdep.h | 3 ++
3 files changed, 122 insertions(+)

diff --git a/gdb/nto-procfs.c b/gdb/nto-procfs.c
index 264d88b..ac54c32 100644
--- a/gdb/nto-procfs.c
+++ b/gdb/nto-procfs.c
@@ -30,6 +30,8 @@
#include <sys/syspage.h>
#include <dirent.h>
#include <sys/netmgr.h>
+#include <sys/auxv.h>
+
#include "gdbcore.h"
#include "inferior.h"
#include "target.h"
@@ -885,6 +887,40 @@ procfs_xfer_partial (struct target_ops *ops, enum target_object object,
{
case TARGET_OBJECT_MEMORY:
return procfs_xfer_memory (readbuf, writebuf, offset, len, xfered_len);
+ case TARGET_OBJECT_AUXV:
+ if (readbuf != NULL)
+ {
+ int err;
+ CORE_ADDR initial_stack;
+ debug_process_t procinfo;
+ /* For 32-bit architecture, size of auxv_t is 8 bytes. */
+ const unsigned int sizeof_auxv_t = sizeof (auxv_t);
+ const unsigned int sizeof_tempbuf = 20 * sizeof_auxv_t;
+ int tempread;
+ gdb_byte *const tempbuf = alloca (sizeof_tempbuf);
+
+ if (tempbuf == NULL)
+ return TARGET_XFER_E_IO;
+
+ err = devctl (ctl_fd, DCMD_PROC_INFO, &procinfo,
+ sizeof procinfo, 0);
+ if (err != EOK)
+ return TARGET_XFER_E_IO;
+
+ /* Similar as in the case of a core file, we read auxv from
+ initial_stack. */
+ initial_stack = procinfo.initial_stack;
+
+ /* procfs is always 'self-hosted', no byte-order manipulation. */
+ tempread = nto_read_auxv_from_initial_stack (initial_stack, tempbuf,
+ sizeof_tempbuf,
+ sizeof (auxv_t));
+ tempread = min (tempread, len) - offset;
+ memcpy (readbuf, tempbuf + offset, tempread);
+ *xfered_len = tempread;
+ return tempread ? TARGET_XFER_OK : TARGET_XFER_EOF;
+ }
+ /* Fallthru */
default:
return ops->beneath->to_xfer_partial (ops->beneath, object, annex,
readbuf, writebuf, offset, len,
diff --git a/gdb/nto-tdep.c b/gdb/nto-tdep.c
index 81ee7fb..62eb88a 100644
--- a/gdb/nto-tdep.c
+++ b/gdb/nto-tdep.c
@@ -394,3 +394,86 @@ nto_initialize_signals (void)
signal_pass_update (SIGPHOTON, 1);
#endif
}
+
+/* Read AUXV from initial_stack. */
+LONGEST
+nto_read_auxv_from_initial_stack (CORE_ADDR initial_stack, gdb_byte *readbuf,
+ LONGEST len, size_t sizeof_auxv_t)
+{
+ gdb_byte targ32[4]; /* For 32 bit target values. */
+ gdb_byte targ64[8]; /* For 64 bit target values. */
+ CORE_ADDR data_ofs = 0;
+ ULONGEST anint;
+ LONGEST len_read = 0;
+ gdb_byte *buff;
+ enum bfd_endian byte_order;
+ int ptr_size;
+
+ if (sizeof_auxv_t == 16)
+ ptr_size = 8;
+ else
+ ptr_size = 4;
+
+ /* Skip over argc, argv and envp... Comment from ldd.c:
+
+ The startup frame is set-up so that we have:
+ auxv
+ NULL
+ ...
+ envp2
+ envp1 <----- void *frame + (argc + 2) * sizeof(char *)
+ NULL
+ ...
+ argv2
+ argv1
+ argc <------ void * frame
+
+ On entry to ldd, frame gives the address of argc on the stack. */
+ /* Read argc. 4 bytes on both 64 and 32 bit arches and luckily little
+ * endian. So we just read first 4 bytes. */
+ if (target_read_memory (initial_stack + data_ofs, targ32, 4) != 0)
+ return 0;
+
+ byte_order = gdbarch_byte_order (target_gdbarch ());
+
+ anint = extract_unsigned_integer (targ32, sizeof (targ32), byte_order);
+
+ /* Size of pointer is assumed to be 4 bytes (32 bit arch.) */
+ data_ofs += (anint + 2) * ptr_size; /* + 2 comes from argc itself and
+ NULL terminating pointer in
+ argv. */
+
+ /* Now loop over env table: */
+ anint = 0;
+ while (target_read_memory (initial_stack + data_ofs, targ64, ptr_size)
+ == 0)
+ {
+ if (extract_unsigned_integer (targ64, ptr_size, byte_order) == 0)
+ anint = 1; /* Keep looping until non-null entry is found. */
+ else if (anint)
+ break;
+ data_ofs += ptr_size;
+ }
+ initial_stack += data_ofs;
+
+ memset (readbuf, 0, len);
+ buff = readbuf;
+ while (len_read <= len-sizeof_auxv_t)
+ {
+ if (target_read_memory (initial_stack + len_read, buff, sizeof_auxv_t)
+ == 0)
+ {
+ /* Both 32 and 64 bit structures have int as the first field. */
+ const ULONGEST a_type
+ = extract_unsigned_integer (buff, sizeof (targ32), byte_order);
+
+ if (a_type == AT_NULL)
+ break;
+ buff += sizeof_auxv_t;
+ len_read += sizeof_auxv_t;
+ }
+ else
+ break;
+ }
+ return len_read;
+}
diff --git a/gdb/nto-tdep.h b/gdb/nto-tdep.h
index bd85d2a..d029f07 100644
--- a/gdb/nto-tdep.h
+++ b/gdb/nto-tdep.h
@@ -168,4 +168,7 @@ int nto_in_dynsym_resolve_code (CORE_ADDR pc);

char *nto_extra_thread_info (struct target_ops *self, struct thread_info *);

+LONGEST nto_read_auxv_from_initial_stack (CORE_ADDR inital_stack,
+ gdb_byte *readbuf,
+ LONGEST len, size_t sizeof_auxv_t);
#endif
--
1.9.1