diff options
Diffstat (limited to 'gdb/nat/linux-ptrace.c')
| -rw-r--r-- | gdb/nat/linux-ptrace.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c index f73058b..7df85c1 100644 --- a/gdb/nat/linux-ptrace.c +++ b/gdb/nat/linux-ptrace.c @@ -24,12 +24,46 @@ #endif #include "gdbsupport/eintr.h" #include "gdbsupport/signals-state-save-restore.h" +#include "gdbsupport/gdb_file.h" /* Stores the ptrace options supported by the running kernel. A value of -1 means we did not check for features yet. A value of 0 means there are no supported features. */ static int supported_ptrace_options = -1; +/* The file from which the kernel.yama.ptrace_scope setting is read. */ + +static constexpr char ptrace_scope_filename[] + = "/proc/sys/kernel/yama/ptrace_scope"; + +/* Reads the yama ptrace_scope value from /proc. Returns the integer value + of ptrace_scope (0, 1, 2, or 3) or -1 if the file cannot be read (e.g., + yama is not enabled). */ + +static int +get_ptrace_scope () +{ + int ptrace_scope = -1; + + /* The /proc file that contains the system-wide ptrace scope setting. */ + gdb_file_up fp (fopen (ptrace_scope_filename, "r")); + if (fp != nullptr) + { + if (fscanf (fp.get (), "%d", &ptrace_scope) != 1) + { + /* If fscanf fails then we couldn't parse the number. But just + to be safe, set the scope back to -1 to indicate no value is + available. */ + ptrace_scope = -1; + } + } + + /* If fp is NULL, it's likely because the yama security module is not + active. In this case, we return -1 to indicate that the scope is + unknown or not applicable. */ + return ptrace_scope; +} + /* Find all possible reasons we could fail to attach PID and return these as a string. An empty string is returned if we didn't find any reason. */ @@ -44,6 +78,13 @@ linux_ptrace_attach_fail_reason (pid_t pid) _("process %d is already traced by process %d"), (int) pid, (int) tracerpid); + int ptrace_scope = get_ptrace_scope (); + if (ptrace_scope > 0) + string_appendf (result, + _("the %s setting of %d might prevent attaching, " + "see 'man 2 ptrace'"), + ptrace_scope_filename, ptrace_scope); + if (linux_proc_pid_is_zombie_nowarn (pid)) string_appendf (result, _("process %d is a zombie - the process has already " |