patch ../102437337.patch

8 files changed, 92 insertions, 45 deletions

diff --git a/README.google b/README.google
index 5686d224b83..1dbf2d345e8 100644
--- a/README.google
+++ b/README.google
@@ -340,3 +340,27 @@ they are an ongoing maintenance burden.
 +	DW_LNS_set_address_from_logical, DW_LNS_set_subprogram,
 +	DW_LNS_inlined_call, DW_LNS_pop_context.
 +	(dwarf_line_number_content_type): New enum.
+--- README.google	2015-09-05 20:17:18.000000000 -0700
++++ README.google	2015-09-05 23:58:27.000000000 -0700
++
++2015-09-05  Doug Evans  <dje@google.com>
++
++	Ref# 20215162
++	* common/common-exceptions.c (exceptions_state_mc_init): Initialize
++	suberror.
++	(throw_it): New arg suberror.  All callers updated.
++	(throw_error_with_suberror): New function.
++	* common/common-exceptions.h (enum errors): New enum value
++	SYSCALL_FAILED_ERROR.
++	(struct gdb_exception): New member suberror.
++	(throw_error_with_suberror): Declare.
++	* inf-ptrace.c (inf_ptrace_attach): Call throw_perror_with_name
++	passing SYSCALL_FAILED_ERROR.
++	* linux-nat.c (linux_nat_attach): Rewrite attach fail error processing.
++	* nat/linux-ptrace.c (linux_ptrace_attach_fail_reason): Make static.
++	Prepend ", " to messages.
++	(linux_ptrace_attach_fail_reason_string): Rewrite message construction.
++	Add kernel.yama.ptrace_scope suggestion.
++	* nat/linux-ptrace.h (linux_ptrace_attach_fail_reason): Delete.
++	* utils.c (perror_string): New arg errno_value.  All callers updated.
++	(throw_perror_with_name): Call throw_error_with_suberror.
diff --git a/gdb/common/common-exceptions.c b/gdb/common/common-exceptions.c
index b300a9d911e..8a33089cdbe 100644
--- a/gdb/common/common-exceptions.c
+++ b/gdb/common/common-exceptions.c
@@ -20,7 +20,7 @@
 #include "common-defs.h"
 #include "common-exceptions.h"
 
-const struct gdb_exception exception_none = { 0, GDB_NO_ERROR, NULL };
+const struct gdb_exception exception_none = { 0, GDB_NO_ERROR, 0, NULL };
 
 #ifndef __cplusplus
 
@@ -314,9 +314,9 @@ static char **exception_messages;
 /* The number of currently allocated entries in exception_messages.  */
 static int exception_messages_size;
 
-static void ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (3, 0)
-throw_it (enum return_reason reason, enum errors error, const char *fmt,
-	  va_list ap)
+static void ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (4, 0)
+throw_it (enum return_reason reason, enum errors error, int suberror,
+	  const char *fmt, va_list ap)
 {
   struct gdb_exception e;
   char *new_message;
@@ -349,6 +349,7 @@ throw_it (enum return_reason reason, enum errors error, const char *fmt,
   /* Create the exception.  */
   e.reason = reason;
   e.error = error;
+  e.suberror = suberror;
   e.message = new_message;
 
   /* Throw the exception.  */
@@ -358,13 +359,13 @@ throw_it (enum return_reason reason, enum errors error, const char *fmt,
 void
 throw_verror (enum errors error, const char *fmt, va_list ap)
 {
-  throw_it (RETURN_ERROR, error, fmt, ap);
+  throw_it (RETURN_ERROR, error, 0, fmt, ap);
 }
 
 void
 throw_vquit (const char *fmt, va_list ap)
 {
-  throw_it (RETURN_QUIT, GDB_NO_ERROR, fmt, ap);
+  throw_it (RETURN_QUIT, GDB_NO_ERROR, 0, fmt, ap);
 }
 
 void
@@ -378,6 +379,17 @@ throw_error (enum errors error, const char *fmt, ...)
 }
 
 void
+throw_error_with_suberror (enum errors error, int suberror,
+			   const char *fmt, ...)
+{
+  va_list args;
+
+  va_start (args, fmt);
+  throw_it (RETURN_ERROR, error, suberror, fmt, args);
+  va_end (args);
+}
+
+void
 throw_quit (const char *fmt, ...)
 {
   va_list args;
diff --git a/gdb/common/common-exceptions.h b/gdb/common/common-exceptions.h
index 2e6a6d94db0..2947ac405e2 100644
--- a/gdb/common/common-exceptions.h
+++ b/gdb/common/common-exceptions.h
@@ -105,6 +105,10 @@ enum errors {
      "_ERROR" is appended to the name.  */
   MAX_COMPLETIONS_REACHED_ERROR,
 
+  /* A system call failed.
+     The "errno" value is in gdb_exception.suberror.  */
+  SYSCALL_FAILED_ERROR,
+
   /* Add more errors here.  */
   NR_ERRORS
 };
@@ -113,6 +117,7 @@ struct gdb_exception
 {
   enum return_reason reason;
   enum errors error;
+  int suberror;
   const char *message;
 };
 
@@ -262,6 +267,9 @@ extern void throw_vquit (const char *fmt, va_list ap)
      ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0);
 extern void throw_error (enum errors error, const char *fmt, ...)
      ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
+extern void throw_error_with_suberror (enum errors error, int suberror,
+				       const char *fmt, ...)
+     ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (3, 4);
 extern void throw_quit (const char *fmt, ...)
      ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2);
 
diff --git a/gdb/inf-ptrace.c b/gdb/inf-ptrace.c
index cd58dfb83ca..2cd63c21931 100644
--- a/gdb/inf-ptrace.c
+++ b/gdb/inf-ptrace.c
@@ -197,7 +197,10 @@ inf_ptrace_attach (struct target_ops *ops, const char *args, int from_tty)
   errno = 0;
   ptrace (PT_ATTACH, pid, (PTRACE_TYPE_ARG3)0, 0);
   if (errno != 0)
-    perror_with_name (("ptrace"));
+    {
+      /* GOOGLE LOCAL: We want the linux caller to see errno.  */
+      throw_perror_with_name (SYSCALL_FAILED_ERROR, _("ptrace"));
+    }
 #else
   error (_("This system does not support attaching to a process"));
 #endif
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 727c8dac0c8..1ce54ffbf74 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -1280,23 +1280,18 @@ linux_nat_attach (struct target_ops *ops, const char *args, int from_tty)
   CATCH (ex, RETURN_MASK_ERROR)
     {
       pid_t pid = parse_pid_to_attach (args);
-      struct buffer buffer;
-      char *message, *buffer_s;
+      char *reason;
 
-      message = xstrdup (ex.message);
-      make_cleanup (xfree, message);
-
-      buffer_init (&buffer);
-      linux_ptrace_attach_fail_reason (pid, &buffer);
-
-      buffer_grow_str0 (&buffer, "");
-      buffer_s = buffer_finish (&buffer);
-      make_cleanup (xfree, buffer_s);
-
-      if (*buffer_s != '\0')
-	throw_error (ex.error, "warning: %s\n%s", buffer_s, message);
+      if (ex.error == SYSCALL_FAILED_ERROR)
+	{
+	  ptid = ptid_build (pid, pid, 0);
+	  reason = linux_ptrace_attach_fail_reason_string (ptid, ex.suberror);
+	  throw_error_with_suberror (ex.error, ex.suberror,
+				     "Cannot attach to process %ld: %s",
+				     (unsigned long) pid, reason);
+	}
       else
-	throw_error (ex.error, "%s", message);
+	throw_error (ex.error, "%s", ex.message);
     }
   END_CATCH
 
diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c
index 1a926f93156..0b593765397 100644
--- a/gdb/nat/linux-ptrace.c
+++ b/gdb/nat/linux-ptrace.c
@@ -32,19 +32,19 @@ static int supported_ptrace_options = -1;
    these as strings to the already initialized BUFFER.  '\0'
    termination of BUFFER must be done by the caller.  */
 
-void
+static void
 linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer)
 {
   pid_t tracerpid;
 
   tracerpid = linux_proc_get_tracerpid_nowarn (pid);
   if (tracerpid > 0)
-    buffer_xml_printf (buffer, _("process %d is already traced "
+    buffer_xml_printf (buffer, _(", process %d is already traced "
 				 "by process %d"),
 		       (int) pid, (int) tracerpid);
 
   if (linux_proc_pid_is_zombie_nowarn (pid))
-    buffer_xml_printf (buffer, _("process %d is a zombie "
+    buffer_xml_printf (buffer, _(", process %d is a zombie "
 				 "- the process has already terminated"),
 		       (int) pid);
 }
@@ -56,22 +56,25 @@ linux_ptrace_attach_fail_reason_string (ptid_t ptid, int err)
 {
   static char *reason_string;
   struct buffer buffer;
-  char *warnings;
   long lwpid = ptid_get_lwp (ptid);
 
   xfree (reason_string);
 
   buffer_init (&buffer);
+  buffer_xml_printf (&buffer, "%s (%d)", strerror (err), err);
   linux_ptrace_attach_fail_reason (lwpid, &buffer);
+  /* GOOGLE LOCAL, ref: 20215162 */
+  if (err == EPERM)
+    {
+      buffer_xml_printf (&buffer, _("\n\
+If your uid matches the uid of the target process, check the setting of\n\
+/proc/sys/kernel/yama/ptrace_scope.  See /etc/sysctl.d/10-ptrace.conf.\n\
+If ptrace scope is enabled, you can lift the restriction with:\n\
+sudo sysctl -w kernel.yama.ptrace_scope=0"));
+    }
+  /* END GOOGLE LOCAL */
   buffer_grow_str0 (&buffer, "");
-  warnings = buffer_finish (&buffer);
-  if (warnings[0] != '\0')
-    reason_string = xstrprintf ("%s (%d), %s",
-				safe_strerror (err), err, warnings);
-  else
-    reason_string = xstrprintf ("%s (%d)",
-				safe_strerror (err), err);
-  xfree (warnings);
+  reason_string = buffer_finish (&buffer);
   return reason_string;
 }
 
diff --git a/gdb/nat/linux-ptrace.h b/gdb/nat/linux-ptrace.h
index be6c39528c9..3d39dadfa0c 100644
--- a/gdb/nat/linux-ptrace.h
+++ b/gdb/nat/linux-ptrace.h
@@ -147,8 +147,6 @@ struct buffer;
 # define TRAP_HWBKPT 4
 #endif
 
-extern void linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer);
-
 /* Find all possible reasons we could have failed to attach to PTID
    and return them as a string.  ERR is the error PTRACE_ATTACH failed
    with (an errno).  The result is stored in a static buffer.  This
diff --git a/gdb/utils.c b/gdb/utils.c
index f32a1f349db..b25216cecf3 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -959,17 +959,17 @@ add_internal_problem_command (struct internal_problem *problem)
 }
 
 /* Return a newly allocated string, containing the PREFIX followed
-   by the system error message for errno (separated by a colon).
+   by the system error message for ERRNO_VALUE (separated by a colon).
 
    The result must be deallocated after use.  */
 
 static char *
-perror_string (const char *prefix)
+perror_string (const char *prefix, int errno_value)
 {
   char *err;
   char *combined;
 
-  err = safe_strerror (errno);
+  err = safe_strerror (errno_value);
   combined = (char *) xmalloc (strlen (err) + strlen (prefix) + 3);
   strcpy (combined, prefix);
   strcat (combined, ": ");
@@ -978,16 +978,18 @@ perror_string (const char *prefix)
   return combined;
 }
 
-/* Print the system error message for errno, and also mention STRING
-   as the file name for which the error was encountered.  Use ERRCODE
-   for the thrown exception.  Then return to command level.  */
+/* Throw an error with the system error message for errno, and also mention
+   STRING as the file name or system call for which the error was encountered.
+   Use ERRCODE for the thrown exception.  */
 
 void
 throw_perror_with_name (enum errors errcode, const char *string)
 {
   char *combined;
+  /* Fetch ERRNO early, you never know which function might modify it.  */
+  int saved_errno = errno;
 
-  combined = perror_string (string);
+  combined = perror_string (string, saved_errno);
   make_cleanup (xfree, combined);
 
   /* I understand setting these is a matter of taste.  Still, some people
@@ -996,7 +998,9 @@ throw_perror_with_name (enum errors errcode, const char *string)
   bfd_set_error (bfd_error_no_error);
   errno = 0;
 
-  throw_error (errcode, _("%s."), combined);
+  throw_error_with_suberror (errcode,
+			     errcode == SYSCALL_FAILED_ERROR ? saved_errno : 0,
+			     _("%s."), combined);
 }
 
 /* See throw_perror_with_name, ERRCODE defaults here to GENERIC_ERROR.  */
@@ -1015,7 +1019,7 @@ perror_warning_with_name (const char *string)
 {
   char *combined;
 
-  combined = perror_string (string);
+  combined = perror_string (string, errno);
   warning (_("%s"), combined);
   xfree (combined);
 }