Add support for callback functions.

Allow the user to specify a callback function that will be invoked
after all threads are paused but before the coredump is generated.

Update the version to 1.3.1.

configure

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for coredumper 1.3.
+# Generated by GNU Autoconf 2.69 for coredumper 1.3.1.
 #
 # Report bugs to <[email protected]>.
 #
@@ -590,8 +590,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='coredumper'
 PACKAGE_TARNAME='coredumper'
-PACKAGE_VERSION='1.3'
-PACKAGE_STRING='coredumper 1.3'
+PACKAGE_VERSION='1.3.1'
+PACKAGE_STRING='coredumper 1.3.1'
 PACKAGE_BUGREPORT='[email protected]'
 PACKAGE_URL=''
 
@@ -1337,7 +1337,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures coredumper 1.3 to adapt to many kinds of systems.
+\`configure' configures coredumper 1.3.1 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1408,7 +1408,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of coredumper 1.3:";;
+     short | recursive ) echo "Configuration of coredumper 1.3.1:";;
    esac
   cat <<\_ACEOF
 
@@ -1521,7 +1521,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-coredumper configure 1.3
+coredumper configure 1.3.1
 generated by GNU Autoconf 2.69
 
 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -2011,7 +2011,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by coredumper $as_me 1.3, which was
+It was created by coredumper $as_me 1.3.1, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   $ $0 $@
@@ -2877,7 +2877,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='coredumper'
- VERSION='1.3'
+ VERSION='1.3.1'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -16664,7 +16664,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by coredumper $as_me 1.3, which was
+This file was extended by coredumper $as_me 1.3.1, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -16730,7 +16730,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-coredumper config.status 1.3
+coredumper config.status 1.3.1
 configured by $0, generated by GNU Autoconf 2.69,
   with options \\"\$ac_cs_config\\"
 

configure.ac

@@ -5,7 +5,7 @@
 # make sure we're interpreted by some minimal autoconf
 AC_PREREQ(2.57)
 
-AC_INIT(coredumper, 1.3, [email protected])
+AC_INIT(coredumper, 1.3.1, [email protected])
 # The argument here is just something that should be in the current directory
 # (for sanity checking)
 AC_CONFIG_SRCDIR(README)

man/CoreDumpParameters.man

@@ -1,7 +1,7 @@
 '\" t
 .TH COREDUMPERPARAMETERS 3 "Mar 11, 2008"
 .SH NAME
-ClearCoreDumpParameters, SetCoreDumpLimited, SetCoreDumpCompressed, SetCoreDumpLimitedByPriority, SetCoreDumpNotes \- functions to initialize and set fields in a CoreDumpParameters structure.
+ClearCoreDumpParameters, SetCoreDumpLimited, SetCoreDumpCompressed, SetCoreDumpLimitedByPriority, SetCoreDumpNotes, SetCoreDumpCallback \- functions to initialize and set fields in a CoreDumpParameters structure.
 .SH SYNOPSIS
 .ad l
 .PP
@@ -18,12 +18,14 @@ ClearCoreDumpParameters, SetCoreDumpLimited, SetCoreDumpCompressed, SetCoreDumpL
     selected_compressor );
 .HP 21
 .BI int\~Set\%Core\%Dump\%Notes(\:struct\~Core\%Dump\%Parameters\ \:* params ,\ \:struct\~Coredumper\%Note\~\:* notes ,\ \:int\~ \:note_count );
+.HP 24
+.BI int\~Set\%Core\%Dump\%Callback(\:struct\~Core\%Dump\%Parameters\ \:* params ,\ \:int\~(* callback_fn )(void*),\ \:void*\~ \:callback_arg );
 .ad b
 .SH DESCRIPTION
 These functions must be used to set the attributes in a CoreDumpParameters
 structure. Combinations of these functions may be used together. For instance
 to produce a compressed core dump with additional notes you should call
-\fBClearCoreDumpParameters\fP(), \fBSetCoreDumpCompressed\fP() and
+\fBClearCoreDumpParameters\fP(), \fBSetCoreDumpCompressed\fP(), and
 \fBSetCoreDumpNotes\fP().
 .PP
 The \fBClearCoreDumpParameters\fP() function clears the given
@@ -73,6 +75,16 @@ type is a user chosen value. The description_size specifies the amount of bytes
 to write from the description pointer in memory to the core dump note. The
 description will be padded to be 4 byte aligned.
 .PP
+The \fBSetCoreDumpCallback\fP() function sets the attributes in
+.IR params
+to add a callback function that will be invoked after all threads in the
+process have been suspended but before any actual core is dumped.  The
+argument provided will be passed to the callback function and is otherwise
+unused by the coredumper library.
+.PP
+If the callback function returns 0, then the core will continue to be dumped.
+If the callback function returns non-0, then the core dump will be failed.
+.PP
 .SH RETURN VALUE
 .PP
 On success 0 will be returned. On error \-1 will be returned and

src/coredumper.c

@@ -291,3 +291,10 @@ int SetCoreDumpNotes(struct CoreDumpParameters *params,
   SetCoreDumpParameter(params, note_count, note_count);
   return 0;
 }
+
+int SetCoreDumpCallback(struct CoreDumpParameters *params,
+                        int (*fn)(void*), void *arg) {
+  SetCoreDumpParameter(params, callback_fn, fn);
+  SetCoreDumpParameter(params, callback_arg, arg);
+  return 0;
+}

src/coredumper_unittest.c

@@ -673,6 +673,16 @@ static int MyWriteCompressedCoreDump(
   return MyWriteCoreDumpWith(&params, file_name);
 }
 
+static int MyCallback(void *arg)
+{
+    int *count = arg;
+    if (*count < 0) {
+        return 1;
+    }
+    ++(*count);
+    return 0;
+}
+
 /* Do not declare this function static, so that the compiler does not get
  * tempted to inline it. We want to be able to see some stack traces.
  */
@@ -828,6 +838,25 @@ void TestCoreDump() {
     CheckExtraNotesWithReadElf(input, output, core_test);
     assert(!unlink(core_test));
 
+    /* Check callback function handling                                      */
+    puts("Checking callback functions");
+    ClearCoreDumpParameters(&note_params);
+    int count = 0;
+    assert(!SetCoreDumpCallback(&note_params, MyCallback, &count));
+    assert(!SetCoreDumpLimited(&note_params, 0x10000));
+    rc = (loop?MyWriteCoreDumpWith:WriteCoreDumpWith)
+          (&note_params, core_test);
+    assert(!rc);
+    CheckWithReadElf(input, output, core_test, "", "cat", "");
+    assert(count == 1);
+    assert(!unlink(core_test));
+    count = -1;
+    rc = (loop?MyWriteCoreDumpWith:WriteCoreDumpWith)
+          (&note_params, core_test);
+    assert(rc);
+    assert(count == -1);
+    assert(unlink(core_test) == -1 && errno == ENOENT);
+
     /* Create a full-size core file                                          */
     puts("Checking uncompressed core files");
     rc = (loop?MyWriteCoreDump:WriteCoreDump)(core_test);

src/elfcore.c

@@ -1673,6 +1673,17 @@ int InternalGetCoreDump(void *frame, int num_threads, pid_t *pids,
   int              pair[2];
   int              main_pid = ((Frame *)frame)->tid;
 
+  const struct CoreDumpParameters *params =
+      va_arg(ap, const struct CoreDumpParameters *);
+
+  int (*callback_fn)(void*) = GetCoreDumpParameter(params, callback_fn);
+  if (callback_fn) {
+    void *arg = GetCoreDumpParameter(params, callback_arg);
+    if (callback_fn(arg) != 0) {
+      goto error;
+    }
+  }
+
   /* Get thread status                                                       */
   memset(puser,          0, sizeof(struct core_user));
   memset(thread_regs,    0, threads * sizeof(struct regs));
@@ -1889,8 +1900,6 @@ int InternalGetCoreDump(void *frame, int num_threads, pid_t *pids,
     int pagesize = sys_sysconf(_SC_PAGESIZE);
     struct kernel_sigset_t old_signals, blocked_signals;
 
-    const struct CoreDumpParameters *params =
-      va_arg(ap, const struct CoreDumpParameters *);
     const char *file_name =
       va_arg(ap, const char *);
     size_t max_length =

src/google/coredumper.h

@@ -88,6 +88,10 @@ struct CoreDumpParameters {
   const struct CoredumperNote *notes;
   /* The amount of notes in the notes array.                                 */
   int note_count;
+  /* Callback function */
+  int (*callback_fn)(void*);
+  /* Callback argument */
+  void *callback_arg;
 };
 
 /* The core file is limited in size and max_length denotes the maximum size. If
@@ -247,6 +251,15 @@ int SetCoreDumpLimitedByPriority(struct CoreDumpParameters *params,
 int SetCoreDumpNotes(struct CoreDumpParameters *params,
                      struct CoredumperNote *notes, int note_count);
 
+/* Sets the coredumper parameters to provide a callback function.
+ * The callback will be invoked after all threads have been suspended but
+ * before any coredump operation is invoked.  The callback argument will be
+ * provided.  If the return value is 0 then the coredump will continue; if the
+ * value is something other than 0 then the coredump will not be generated.
+ */
+int SetCoreDumpCallback(struct CoreDumpParameters *params,
+                        int (*fn)(void*), void *arg);
+
 #ifdef __cplusplus
 }
 #endif

src/libcoredumper.sym

@@ -19,3 +19,4 @@ SetCoreDumpCompressed
 SetCoreDumpLimited
 SetCoreDumpLimitedByPriority
 SetCoreDumpNotes
+SetCoreDumpCallback