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6d30ada87b
Andrew reported that the previous change to gdb.Inferior.read_memory & friends introducing scoped_restore_current_inferior_for_memory broke gdb.dap/stop-at-main.exp. This is also reported as PR dap/30644. The root of the problem is that all the methods that now use scoped_restore_current_inferior_for_memory cause GDB to crash with a failed assert if they are run on an inferior that is not yet started. E.g.: (gdb) python i = gdb.selected_inferior () (gdb) python i.read_memory (4,4) gdb/thread.c:626: internal-error: any_thread_of_inferior: Assertion `inf->pid != 0' failed. This patch fixes the problem by removing scoped_restore_current_inferior_for_memory's ctor ptid parameter and the any_thread_of_inferior calls completely, and making scoped_restore_current_inferior_for_memory switch inferior_ptid to a pid ptid. I was a little worried that some port might be assuming inferior_ptid points at a thread in the xfer_partial memory access routines. We know that anything that supports forks must not assume that, due to how detach_breakpoints works. I looked at a number of xfer_partial implementations, and didn't see anything that is looking at inferior_ptid in a way that would misbehave. I'm thinking that we could go forward with this and just fix ports if they break. While on some ports like on AMD GPU we have thread-specific address spaces, and so when accessing memory for those address spaces, we must have the right thread context (via inferior_ptid) selected, in Inferior.read_memory, we only have the inferior to work with, so this API as is can't be used to access thread-specific address spaces. IOW, it can only be used to access the global address space that is visible to both the CPU and the GPUs. In proc-service.c:ps_xfer_memory, the other spot using scoped_restore_current_inferior_for_memory, we're always accessing per-inferior memory. If we end up using scoped_restore_current_inferior_for_memory later to set up the context to read memory from a specific thread, then we can add an alternative ctor that takes a thread_info pointer, and make inferior_ptid point to the thread, for example. New test added to gdb.python/py-inferior.exp, exercising Inferior.read_memory without execution. No regressions on native and extended-gdbserver x86_64 GNU/Linux. Reviewed-By: Tom Tromey <tom@tromey.com> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30644 Change-Id: I11309c5ddbbb51a4594cf63c21b3858bfd9aed19
217 lines
5.8 KiB
C
217 lines
5.8 KiB
C
/* <proc_service.h> implementation.
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Copyright (C) 1999-2023 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "gdbcore.h"
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#include "inferior.h"
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#include "gdbthread.h"
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#include "symtab.h"
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#include "target.h"
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#include "regcache.h"
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#include "objfiles.h"
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#include "gdb_proc_service.h"
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#include <sys/procfs.h>
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/* Prototypes for supply_gregset etc. */
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#include "gregset.h"
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/* Helper functions. */
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/* Convert a psaddr_t to a CORE_ADDR. */
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static CORE_ADDR
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ps_addr_to_core_addr (psaddr_t addr)
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{
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if (current_program_space->exec_bfd ()
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&& bfd_get_sign_extend_vma (current_program_space->exec_bfd ()))
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return (intptr_t) addr;
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else
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return (uintptr_t) addr;
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}
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/* Convert a CORE_ADDR to a psaddr_t. */
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static psaddr_t
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core_addr_to_ps_addr (CORE_ADDR addr)
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{
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if (current_program_space->exec_bfd ()
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&& bfd_get_sign_extend_vma (current_program_space->exec_bfd ()))
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return (psaddr_t) (intptr_t) addr;
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else
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return (psaddr_t) (uintptr_t) addr;
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}
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/* Transfer LEN bytes of memory between BUF and address ADDR in the
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process specified by PH. If WRITE, transfer them to the process,
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else transfer them from the process. Returns PS_OK for success,
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PS_ERR on failure.
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This is a helper function for ps_pdread and ps_pdwrite. */
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static ps_err_e
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ps_xfer_memory (const struct ps_prochandle *ph, psaddr_t addr,
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gdb_byte *buf, size_t len, int write)
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{
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scoped_restore_current_inferior_for_memory save_inferior (ph->thread->inf);
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CORE_ADDR core_addr = ps_addr_to_core_addr (addr);
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int ret;
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if (write)
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ret = target_write_memory (core_addr, buf, len);
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else
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ret = target_read_memory (core_addr, buf, len);
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return (ret == 0 ? PS_OK : PS_ERR);
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}
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/* Search for the symbol named NAME within the object named OBJ within
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the target process PH. If the symbol is found the address of the
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symbol is stored in SYM_ADDR. */
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ps_err_e
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ps_pglobal_lookup (struct ps_prochandle *ph, const char *obj,
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const char *name, psaddr_t *sym_addr)
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{
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inferior *inf = ph->thread->inf;
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scoped_restore_current_program_space restore_pspace;
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set_current_program_space (inf->pspace);
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/* FIXME: kettenis/2000-09-03: What should we do with OBJ? */
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bound_minimal_symbol ms = lookup_minimal_symbol (name, NULL, NULL);
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if (ms.minsym == NULL)
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return PS_NOSYM;
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*sym_addr = core_addr_to_ps_addr (ms.value_address ());
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return PS_OK;
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}
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/* Read SIZE bytes from the target process PH at address ADDR and copy
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them into BUF. */
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ps_err_e
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ps_pdread (struct ps_prochandle *ph, psaddr_t addr, void *buf, size_t size)
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{
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return ps_xfer_memory (ph, addr, (gdb_byte *) buf, size, 0);
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}
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/* Write SIZE bytes from BUF into the target process PH at address ADDR. */
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ps_err_e
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ps_pdwrite (struct ps_prochandle *ph, psaddr_t addr,
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const void *buf, size_t size)
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{
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return ps_xfer_memory (ph, addr, (gdb_byte *) buf, size, 1);
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}
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/* Get a regcache for LWPID using its inferior's "main" architecture,
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which is the register set libthread_db expects to be using. In
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multi-arch debugging scenarios, the thread's architecture may
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differ from the inferior's "main" architecture. */
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static struct regcache *
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get_ps_regcache (struct ps_prochandle *ph, lwpid_t lwpid)
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{
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inferior *inf = ph->thread->inf;
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return get_thread_arch_regcache (inf->process_target (),
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ptid_t (inf->pid, lwpid),
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inf->gdbarch);
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}
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/* Get the general registers of LWP LWPID within the target process PH
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and store them in GREGSET. */
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ps_err_e
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ps_lgetregs (struct ps_prochandle *ph, lwpid_t lwpid, prgregset_t gregset)
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{
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struct regcache *regcache = get_ps_regcache (ph, lwpid);
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target_fetch_registers (regcache, -1);
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fill_gregset (regcache, (gdb_gregset_t *) gregset, -1);
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return PS_OK;
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}
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/* Set the general registers of LWP LWPID within the target process PH
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from GREGSET. */
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ps_err_e
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ps_lsetregs (struct ps_prochandle *ph, lwpid_t lwpid, const prgregset_t gregset)
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{
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struct regcache *regcache = get_ps_regcache (ph, lwpid);
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supply_gregset (regcache, (const gdb_gregset_t *) gregset);
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target_store_registers (regcache, -1);
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return PS_OK;
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}
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/* Get the floating-point registers of LWP LWPID within the target
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process PH and store them in FPREGSET. */
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ps_err_e
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ps_lgetfpregs (struct ps_prochandle *ph, lwpid_t lwpid,
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prfpregset_t *fpregset)
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{
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struct regcache *regcache = get_ps_regcache (ph, lwpid);
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target_fetch_registers (regcache, -1);
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fill_fpregset (regcache, (gdb_fpregset_t *) fpregset, -1);
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return PS_OK;
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}
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/* Set the floating-point registers of LWP LWPID within the target
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process PH from FPREGSET. */
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ps_err_e
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ps_lsetfpregs (struct ps_prochandle *ph, lwpid_t lwpid,
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const prfpregset_t *fpregset)
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{
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struct regcache *regcache = get_ps_regcache (ph, lwpid);
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supply_fpregset (regcache, (const gdb_fpregset_t *) fpregset);
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target_store_registers (regcache, -1);
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return PS_OK;
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}
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/* Return overall process id of the target PH. Special for GNU/Linux
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-- not used on Solaris. */
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pid_t
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ps_getpid (struct ps_prochandle *ph)
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{
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return ph->thread->ptid.pid ();
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}
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void _initialize_proc_service ();
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void
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_initialize_proc_service ()
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{
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/* This function solely exists to make sure this module is linked
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into the final binary. */
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}
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