From 1b919490e8ba30bf1d6941df0ed112b0e557017e Mon Sep 17 00:00:00 2001 From: Vyacheslav Barinov Date: Wed, 4 Jul 2018 16:13:29 +0100 Subject: 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 Pedro Alves * 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 Pedro Alves * linux-low.c (initialize_low): Call linux_proc_init_warnings. --- gdb/nat/linux-procfs.c | 17 +++++++++++++++++ gdb/nat/linux-procfs.h | 5 +++++ 2 files changed, 22 insertions(+) (limited to 'gdb/nat') diff --git a/gdb/nat/linux-procfs.c b/gdb/nat/linux-procfs.c index 1c236c5..6c15ea5 100644 --- a/gdb/nat/linux-procfs.c +++ b/gdb/nat/linux-procfs.c @@ -357,3 +357,20 @@ linux_proc_pid_to_exec_file (int pid) return buf; } + +/* See linux-procfs.h. */ + +void +linux_proc_init_warnings () +{ + static bool warned = false; + + if (warned) + return; + warned = true; + + struct stat st; + + if (stat ("/proc/self", &st) != 0) + warning (_("/proc is not accessible.")); +} diff --git a/gdb/nat/linux-procfs.h b/gdb/nat/linux-procfs.h index efb2911..2f8932e 100644 --- a/gdb/nat/linux-procfs.h +++ b/gdb/nat/linux-procfs.h @@ -80,4 +80,9 @@ extern int linux_proc_task_list_dir_exists (pid_t pid); 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 */ -- cgit v1.1