binutils-gdb/gdb/nat/linux-procfs.h
Vyacheslav Barinov 1b919490e8 Warn if /proc is not accessible
There's a buildroot where I want to debug a binary, and I tried to
connect to it from outside, but got very weird errors like
architecture mismatch or protocol errors.  At last, after switching on
'--debug' for gdbserver I found a message 'Can't open /proc/pid/'
message and suddenly found that I forgot to mount procfs in my
buildroot.

Make discovering the problem easier by making GDB / GDBserver warn
(even without --debug) if /proc can not be accessed.

Native debugging:

 (gdb) start
 Temporary breakpoint 1 at 0x400835: file test.c, line 10.
 Starting program: /tmp/test
 warning: /proc is not accessible.

GDBserver/remote debugging:

 $ ./gdbserver :9999 ./gdbserver
 gdbserver: /proc is not accessible.

gdb/ChangeLog:
2018-07-04  Vyacheslav Barinov  <v.barinov@samsung.com>
	    Pedro Alves  <palves@redhat.com>

	* linux-nat.c (linux_init_ptrace): Rename to ...
	(linux_init_ptrace_procfs): ... this.  Call
	linux_proc_init_warnings.
	(linux_nat_target::post_attach)
	(linux_nat_target::post_startup_inferior): Adjust.
	* nat/linux-procfs.c (linux_proc_init_warnings): Define function.
	* nat/linux-procfs.h (linux_proc_init_warnings): Declare function.

gdb/gdbserver/ChangeLog:
2018-07-04  Vyacheslav Barinov  <v.barinov@samsung.com>
	    Pedro Alves  <palves@redhat.com>

	* linux-low.c (initialize_low): Call linux_proc_init_warnings.
2018-07-04 16:13:29 +01:00

89 lines
3.2 KiB
C

/* Linux-specific PROCFS manipulation routines.
Copyright (C) 2011-2018 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/>. */
#ifndef COMMON_LINUX_PROCFS_H
#define COMMON_LINUX_PROCFS_H
#include <unistd.h>
/* Return the TGID of LWPID from /proc/pid/status. Returns -1 if not
found. Failure to open the /proc file results in a warning. */
extern int linux_proc_get_tgid (pid_t lwpid);
/* Return the TracerPid of LWPID from /proc/pid/status. Returns -1 if
not found. Does not warn on failure to open the /proc file. */
extern pid_t linux_proc_get_tracerpid_nowarn (pid_t lwpid);
/* Detect `T (stopped)' in `/proc/PID/status'.
Other states including `T (tracing stop)' are reported as false. */
extern int linux_proc_pid_is_stopped (pid_t pid);
extern int linux_proc_pid_is_trace_stopped_nowarn (pid_t pid);
/* Return non-zero if PID is a zombie. Failure to open the
/proc/pid/status file results in a warning. */
extern int linux_proc_pid_is_zombie (pid_t pid);
/* Return non-zero if PID is a zombie. Does not warn on failure to
open the /proc file. */
extern int linux_proc_pid_is_zombie_nowarn (pid_t pid);
/* Return non-zero if /proc/PID/status indicates that PID is gone
(i.e., in Z/Zombie or X/Dead state). Failure to open the /proc
file is assumed to indicate the thread is gone. */
extern int linux_proc_pid_is_gone (pid_t pid);
/* Return a string giving the thread's name or NULL if the
information is unavailable. The returned value points to a statically
allocated buffer. The value therefore becomes invalid at the next
linux_proc_tid_get_name call. */
extern const char *linux_proc_tid_get_name (ptid_t ptid);
/* Callback function for linux_proc_attach_tgid_threads. If the PTID
thread is not yet known, try to attach to it and return true,
otherwise return false. */
typedef int (*linux_proc_attach_lwp_func) (ptid_t ptid);
/* If PID is a tgid, scan the /proc/PID/task/ directory for existing
threads, and call FUNC for each thread found. */
extern void linux_proc_attach_tgid_threads (pid_t pid,
linux_proc_attach_lwp_func func);
/* Return true if the /proc/PID/task/ directory exists. */
extern int linux_proc_task_list_dir_exists (pid_t pid);
/* Return the full absolute name of the executable file that was run
to create the process PID. The returned value persists until this
function is next called. */
extern char *linux_proc_pid_to_exec_file (int pid);
/* Display possible problems on this system. Display them only once
per GDB execution. */
extern void linux_proc_init_warnings ();
#endif /* COMMON_LINUX_PROCFS_H */