i#7046 Add Linux support to dr_create_memory_dump.

api/docs/release.dox

@@ -126,16 +126,8 @@ clients.
 
 The changes between version \DR_VERSION and 11.0.0 include the following compatibility
 changes:
- - Added X64 Linux support to dr_create_memory_dump().
-
-Further non-compatibility-affecting changes include:
-
-**************************************************
-<hr>
-
-The changes between version 11.0.0 and 10.0.0 include the following compatibility
-changes:
- - No compatibility changes.
+ - Added X64 Linux support to dr_create_memory_dump(). This API has the same
+   restriction as dr_suspend_all_other_threads_ex().
 
 Further non-compatibility-affecting changes include:
  - No changes yet.

core/unix/coredump.c

@@ -30,10 +30,8 @@
 #include <sys/mman.h>
 #include "../globals.h"
 
-#include <stdio.h>
-
-#include "../hashtable.h"
 #include "../os_shared.h"
+#include "../synch.h"
 #include "dr_tools.h"
 #include "elf_defines.h"
 #include "memquery.h"
@@ -42,6 +40,7 @@
 #define MAX_SECTION_NAME_BUFFER_SIZE 8192
 #define SECTION_HEADER_TABLE ".shstrtab"
 #define VVAR_SECTION "[vvar]"
+#define VSYSCALL_SECTION "[vsyscall]"
 
 typedef struct _section_header_info_t {
     app_pc vm_start;
@@ -158,14 +157,11 @@ write_section_header(DR_PARAM_IN file_t elf_file,
 static bool
 os_dump_core_internal(void)
 {
-    strhash_table_t *string_htable =
-        strhash_hash_create(GLOBAL_DCONTEXT, /*bits=*/8, /*load_factor_percent=*/80,
-                            /*table_flags=*/0, NULL _IF_DEBUG("mmap-string-table"));
-
     // Insert a null string at the beginning for sections with no comment.
     char string_table[MAX_SECTION_NAME_BUFFER_SIZE];
     // Reserve the first byte for sections without a name.
     string_table[0] = '\0';
+    string_table[1] = '\0';
     ELF_ADDR string_table_offset = 1;
     ELF_OFF section_count = 0;
     ELF_OFF section_data_size = 0;
@@ -186,16 +182,17 @@ os_dump_core_internal(void)
     // the section name in the section name table.
     while (memquery_iterator_next(&iter)) {
         // Skip non-readable section.
-        if (iter.prot == MEMPROT_NONE || strcmp(iter.comment, VVAR_SECTION) == 0) {
+        if (iter.prot == MEMPROT_NONE || strcmp(iter.comment, VVAR_SECTION) == 0 ||
+            strcmp(iter.comment, VSYSCALL_SECTION) == 0) {
             continue;
         }
         ELF_ADDR offset = 0;
         if (iter.comment != NULL && iter.comment[0] != '\0') {
-            offset = (ELF_ADDR)strhash_hash_lookup(GLOBAL_DCONTEXT, string_htable,
-                                                   iter.comment);
+            const char *pos = strstr(&string_table[1], iter.comment);
+            if (pos != NULL) {
+                offset = pos - string_table;
+            }
             if (offset == 0) {
-                strhash_hash_add(GLOBAL_DCONTEXT, string_htable, iter.comment,
-                                 (void *)string_table_offset);
                 const size_t comment_len = d_r_strlen(iter.comment);
                 if (comment_len + string_table_offset > MAX_SECTION_NAME_BUFFER_SIZE) {
                     SYSLOG_INTERNAL_ERROR("Section name table is too small to store "
@@ -269,6 +266,10 @@ os_dump_core_internal(void)
         if (written != length) {
             SYSLOG_INTERNAL_ERROR("Failed to write the requested memory content into "
                                   "the core dump file.");
+            SYSLOG_INTERNAL_ERROR(
+                "section: %s, prot: %x, length: %d, written: %d\n",
+                &string_table[section_header_info[section_index].name_offset],
+                section_header_info[section_index].prot, length, written);
             os_close(elf_file);
             return false;
         }
@@ -319,7 +320,6 @@ os_dump_core_internal(void)
     }
 
     os_close(elf_file);
-    strhash_hash_destroy(GLOBAL_DCONTEXT, string_htable);
     return true;
 }
 
@@ -329,17 +329,23 @@ os_dump_core_internal(void)
 bool
 os_dump_core_live(void)
 {
-    uint num_threads;
-    void **drcontexts = NULL;
     // Suspend all threads including native threads to ensure the memory regions
     // do not change in the middle of the core dump.
-    if (!dr_suspend_all_other_threads_ex(&drcontexts, &num_threads, NULL,
-                                         DR_SUSPEND_NATIVE)) {
+    int num_threads;
+    thread_record_t **threads;
+    if (!synch_with_all_threads(THREAD_SYNCH_SUSPENDED_VALID_MCONTEXT_OR_NO_XFER,
+                                &threads, &num_threads, THREAD_SYNCH_NO_LOCKS_NO_XFER,
+                                /* If we fail to suspend a thread, there is a
+                                 * risk of deadlock in the child, so it's worth
+                                 * retrying on failure.
+                                 */
+                                THREAD_SYNCH_SUSPEND_FAILURE_IGNORE)) {
         return false;
     }
+
     const bool ret = os_dump_core_internal();
-    if (!dr_resume_all_other_threads(drcontexts, num_threads)) {
-        return false;
-    }
+
+    end_synch_with_all_threads(threads, num_threads,
+                               /*resume=*/true);
     return ret;
 }

suite/tests/CMakeLists.txt

@@ -2646,6 +2646,10 @@ if (NOT ANDROID) # TODO i#38: Port test to Android.
     torunonly_ci(client.attach_blocking linux.infloop client.attach_test.dll
       client-interface/attach_blocking.runall "" "" "")
   endif ()
+  if (LINUX AND X64)
+    # TODO i#7046: Verify the content of the output file.
+    tobuild_ci(client.memory_dump_test client-interface/memory_dump_test.c "" "" "")
+  endif ()
 endif ()
 
 if (UNIX)

suite/tests/client-interface/memory_dump_test.dll.c

@@ -62,7 +62,6 @@ DR_EXPORT
 void
 dr_init(client_id_t id)
 {
-    void *drcontext = dr_get_current_drcontext();
     dr_register_exit_event(dr_exit);
     dr_register_thread_init_event(dr_thread_init);
     dr_fprintf(STDERR, "thank you for testing memory dump\n");