--- a/src/jdk.hotspot.agent/linux/native/libsaproc/ps_core.c Thu Oct 17 20:27:44 2019 +0100
+++ b/src/jdk.hotspot.agent/linux/native/libsaproc/ps_core.c Thu Oct 17 20:53:35 2019 +0100
@@ -31,336 +31,14 @@
#include <elf.h>
#include <link.h>
#include "libproc_impl.h"
+#include "ps_core_common.h"
#include "proc_service.h"
#include "salibelf.h"
-#include "cds.h"
// This file has the libproc implementation to read core files.
// For live processes, refer to ps_proc.c. Portions of this is adapted
// /modelled after Solaris libproc.so (in particular Pcore.c)
-//----------------------------------------------------------------------
-// ps_prochandle cleanup helper functions
-
-// close all file descriptors
-static void close_files(struct ps_prochandle* ph) {
- lib_info* lib = NULL;
-
- // close core file descriptor
- if (ph->core->core_fd >= 0)
- close(ph->core->core_fd);
-
- // close exec file descriptor
- if (ph->core->exec_fd >= 0)
- close(ph->core->exec_fd);
-
- // close interp file descriptor
- if (ph->core->interp_fd >= 0)
- close(ph->core->interp_fd);
-
- // close class share archive file
- if (ph->core->classes_jsa_fd >= 0)
- close(ph->core->classes_jsa_fd);
-
- // close all library file descriptors
- lib = ph->libs;
- while (lib) {
- int fd = lib->fd;
- if (fd >= 0 && fd != ph->core->exec_fd) {
- close(fd);
- }
- lib = lib->next;
- }
-}
-
-// clean all map_info stuff
-static void destroy_map_info(struct ps_prochandle* ph) {
- map_info* map = ph->core->maps;
- while (map) {
- map_info* next = map->next;
- free(map);
- map = next;
- }
-
- if (ph->core->map_array) {
- free(ph->core->map_array);
- }
-
- // Part of the class sharing workaround
- map = ph->core->class_share_maps;
- while (map) {
- map_info* next = map->next;
- free(map);
- map = next;
- }
-}
-
-// ps_prochandle operations
-static void core_release(struct ps_prochandle* ph) {
- if (ph->core) {
- close_files(ph);
- destroy_map_info(ph);
- free(ph->core);
- }
-}
-
-static map_info* allocate_init_map(int fd, off_t offset, uintptr_t vaddr, size_t memsz) {
- map_info* map;
- if ( (map = (map_info*) calloc(1, sizeof(map_info))) == NULL) {
- print_debug("can't allocate memory for map_info\n");
- return NULL;
- }
-
- // initialize map
- map->fd = fd;
- map->offset = offset;
- map->vaddr = vaddr;
- map->memsz = memsz;
- return map;
-}
-
-// add map info with given fd, offset, vaddr and memsz
-static map_info* add_map_info(struct ps_prochandle* ph, int fd, off_t offset,
- uintptr_t vaddr, size_t memsz) {
- map_info* map;
- if ((map = allocate_init_map(fd, offset, vaddr, memsz)) == NULL) {
- return NULL;
- }
-
- // add this to map list
- map->next = ph->core->maps;
- ph->core->maps = map;
- ph->core->num_maps++;
-
- return map;
-}
-
-// Part of the class sharing workaround
-static map_info* add_class_share_map_info(struct ps_prochandle* ph, off_t offset,
- uintptr_t vaddr, size_t memsz) {
- map_info* map;
- if ((map = allocate_init_map(ph->core->classes_jsa_fd,
- offset, vaddr, memsz)) == NULL) {
- return NULL;
- }
-
- map->next = ph->core->class_share_maps;
- ph->core->class_share_maps = map;
- return map;
-}
-
-// Return the map_info for the given virtual address. We keep a sorted
-// array of pointers in ph->map_array, so we can binary search.
-static map_info* core_lookup(struct ps_prochandle *ph, uintptr_t addr) {
- int mid, lo = 0, hi = ph->core->num_maps - 1;
- map_info *mp;
-
- while (hi - lo > 1) {
- mid = (lo + hi) / 2;
- if (addr >= ph->core->map_array[mid]->vaddr) {
- lo = mid;
- } else {
- hi = mid;
- }
- }
-
- if (addr < ph->core->map_array[hi]->vaddr) {
- mp = ph->core->map_array[lo];
- } else {
- mp = ph->core->map_array[hi];
- }
-
- if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) {
- return (mp);
- }
-
-
- // Part of the class sharing workaround
- // Unfortunately, we have no way of detecting -Xshare state.
- // Check out the share maps atlast, if we don't find anywhere.
- // This is done this way so to avoid reading share pages
- // ahead of other normal maps. For eg. with -Xshare:off we don't
- // want to prefer class sharing data to data from core.
- mp = ph->core->class_share_maps;
- if (mp) {
- print_debug("can't locate map_info at 0x%lx, trying class share maps\n", addr);
- }
- while (mp) {
- if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) {
- print_debug("located map_info at 0x%lx from class share maps\n", addr);
- return (mp);
- }
- mp = mp->next;
- }
-
- print_debug("can't locate map_info at 0x%lx\n", addr);
- return (NULL);
-}
-
-//---------------------------------------------------------------
-// Part of the class sharing workaround:
-//
-// With class sharing, pages are mapped from classes.jsa file.
-// The read-only class sharing pages are mapped as MAP_SHARED,
-// PROT_READ pages. These pages are not dumped into core dump.
-// With this workaround, these pages are read from classes.jsa.
-
-static bool read_jboolean(struct ps_prochandle* ph, uintptr_t addr, jboolean* pvalue) {
- jboolean i;
- if (ps_pdread(ph, (psaddr_t) addr, &i, sizeof(i)) == PS_OK) {
- *pvalue = i;
- return true;
- } else {
- return false;
- }
-}
-
-static bool read_pointer(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* pvalue) {
- uintptr_t uip;
- if (ps_pdread(ph, (psaddr_t) addr, (char *)&uip, sizeof(uip)) == PS_OK) {
- *pvalue = uip;
- return true;
- } else {
- return false;
- }
-}
-
-// used to read strings from debuggee
-static bool read_string(struct ps_prochandle* ph, uintptr_t addr, char* buf, size_t size) {
- size_t i = 0;
- char c = ' ';
-
- while (c != '\0') {
- if (ps_pdread(ph, (psaddr_t) addr, &c, sizeof(char)) != PS_OK) {
- return false;
- }
- if (i < size - 1) {
- buf[i] = c;
- } else {
- // smaller buffer
- return false;
- }
- i++; addr++;
- }
-
- buf[i] = '\0';
- return true;
-}
-
-#define USE_SHARED_SPACES_SYM "UseSharedSpaces"
-// mangled name of Arguments::SharedArchivePath
-#define SHARED_ARCHIVE_PATH_SYM "_ZN9Arguments17SharedArchivePathE"
-#define LIBJVM_NAME "/libjvm.so"
-
-static bool init_classsharing_workaround(struct ps_prochandle* ph) {
- lib_info* lib = ph->libs;
- while (lib != NULL) {
- // we are iterating over shared objects from the core dump. look for
- // libjvm.so.
- const char *jvm_name = 0;
- if ((jvm_name = strstr(lib->name, LIBJVM_NAME)) != 0) {
- char classes_jsa[PATH_MAX];
- CDSFileMapHeaderBase header;
- int fd = -1;
- int m = 0;
- size_t n = 0;
- uintptr_t base = 0, useSharedSpacesAddr = 0;
- uintptr_t sharedArchivePathAddrAddr = 0, sharedArchivePathAddr = 0;
- jboolean useSharedSpaces = 0;
- map_info* mi = 0;
-
- memset(classes_jsa, 0, sizeof(classes_jsa));
- jvm_name = lib->name;
- useSharedSpacesAddr = lookup_symbol(ph, jvm_name, USE_SHARED_SPACES_SYM);
- if (useSharedSpacesAddr == 0) {
- print_debug("can't lookup 'UseSharedSpaces' flag\n");
- return false;
- }
-
- // Hotspot vm types are not exported to build this library. So
- // using equivalent type jboolean to read the value of
- // UseSharedSpaces which is same as hotspot type "bool".
- if (read_jboolean(ph, useSharedSpacesAddr, &useSharedSpaces) != true) {
- print_debug("can't read the value of 'UseSharedSpaces' flag\n");
- return false;
- }
-
- if ((int)useSharedSpaces == 0) {
- print_debug("UseSharedSpaces is false, assuming -Xshare:off!\n");
- return true;
- }
-
- sharedArchivePathAddrAddr = lookup_symbol(ph, jvm_name, SHARED_ARCHIVE_PATH_SYM);
- if (sharedArchivePathAddrAddr == 0) {
- print_debug("can't lookup shared archive path symbol\n");
- return false;
- }
-
- if (read_pointer(ph, sharedArchivePathAddrAddr, &sharedArchivePathAddr) != true) {
- print_debug("can't read shared archive path pointer\n");
- return false;
- }
-
- if (read_string(ph, sharedArchivePathAddr, classes_jsa, sizeof(classes_jsa)) != true) {
- print_debug("can't read shared archive path value\n");
- return false;
- }
-
- print_debug("looking for %s\n", classes_jsa);
- // open the class sharing archive file
- fd = pathmap_open(classes_jsa);
- if (fd < 0) {
- print_debug("can't open %s!\n", classes_jsa);
- ph->core->classes_jsa_fd = -1;
- return false;
- } else {
- print_debug("opened %s\n", classes_jsa);
- }
-
- // read CDSFileMapHeaderBase from the file
- memset(&header, 0, sizeof(CDSFileMapHeaderBase));
- if ((n = read(fd, &header, sizeof(CDSFileMapHeaderBase)))
- != sizeof(CDSFileMapHeaderBase)) {
- print_debug("can't read shared archive file map header from %s\n", classes_jsa);
- close(fd);
- return false;
- }
-
- // check file magic
- if (header._magic != CDS_ARCHIVE_MAGIC) {
- print_debug("%s has bad shared archive file magic number 0x%x, expecting 0x%x\n",
- classes_jsa, header._magic, CDS_ARCHIVE_MAGIC);
- close(fd);
- return false;
- }
-
- // check version
- if (header._version != CURRENT_CDS_ARCHIVE_VERSION) {
- print_debug("%s has wrong shared archive file version %d, expecting %d\n",
- classes_jsa, header._version, CURRENT_CDS_ARCHIVE_VERSION);
- close(fd);
- return false;
- }
-
- ph->core->classes_jsa_fd = fd;
- // add read-only maps from classes.jsa to the list of maps
- for (m = 0; m < NUM_CDS_REGIONS; m++) {
- if (header._space[m]._read_only) {
- base = (uintptr_t) header._space[m]._addr._base;
- // no need to worry about the fractional pages at-the-end.
- // possible fractional pages are handled by core_read_data.
- add_class_share_map_info(ph, (off_t) header._space[m]._file_offset,
- base, (size_t) header._space[m]._used);
- print_debug("added a share archive map at 0x%lx\n", base);
- }
- }
- return true;
- }
- lib = lib->next;
- }
- return true;
-}
-
//---------------------------------------------------------------------------
// functions to handle map_info
@@ -839,8 +517,51 @@
#define LD_BASE_OFFSET offsetof(struct r_debug, r_ldbase)
#define LINK_MAP_ADDR_OFFSET offsetof(struct link_map, l_addr)
#define LINK_MAP_NAME_OFFSET offsetof(struct link_map, l_name)
+#define LINK_MAP_LD_OFFSET offsetof(struct link_map, l_ld)
#define LINK_MAP_NEXT_OFFSET offsetof(struct link_map, l_next)
+// Calculate the load address of shared library
+// on prelink-enabled environment.
+//
+// In case of GDB, it would be calculated by offset of link_map.l_ld
+// and the address of .dynamic section.
+// See GDB implementation: lm_addr_check @ solib-svr4.c
+static uintptr_t calc_prelinked_load_address(struct ps_prochandle* ph, int lib_fd, ELF_EHDR* elf_ehdr, uintptr_t link_map_addr) {
+ ELF_PHDR *phbuf;
+ uintptr_t lib_ld;
+ uintptr_t lib_dyn_addr = 0L;
+ uintptr_t load_addr;
+ int i;
+
+ phbuf = read_program_header_table(lib_fd, elf_ehdr);
+ if (phbuf == NULL) {
+ print_debug("can't read program header of shared object\n");
+ return 0L;
+ }
+
+ // Get the address of .dynamic section from shared library.
+ for (i = 0; i < elf_ehdr->e_phnum; i++) {
+ if (phbuf[i].p_type == PT_DYNAMIC) {
+ lib_dyn_addr = phbuf[i].p_vaddr;
+ break;
+ }
+ }
+
+ free(phbuf);
+
+ if (ps_pdread(ph, (psaddr_t)link_map_addr + LINK_MAP_LD_OFFSET,
+ &lib_ld, sizeof(uintptr_t)) != PS_OK) {
+ print_debug("can't read address of dynamic section in shared object\n");
+ return 0L;
+ }
+
+ // Return the load address which is calculated by the address of .dynamic
+ // and link_map.l_ld .
+ load_addr = lib_ld - lib_dyn_addr;
+ print_debug("lib_ld = 0x%lx, lib_dyn_addr = 0x%lx -> lib_base_diff = 0x%lx\n", lib_ld, lib_dyn_addr, load_addr);
+ return load_addr;
+}
+
// read shared library info from runtime linker's data structures.
// This work is done by librtlb_db in Solaris
static bool read_shared_lib_info(struct ps_prochandle* ph) {
@@ -942,6 +663,14 @@
// continue with other libraries...
} else {
if (read_elf_header(lib_fd, &elf_ehdr)) {
+ if (lib_base_diff == 0x0L) {
+ lib_base_diff = calc_prelinked_load_address(ph, lib_fd, &elf_ehdr, link_map_addr);
+ if (lib_base_diff == 0x0L) {
+ close(lib_fd);
+ return false;
+ }
+ }
+
lib_base = lib_base_diff + find_base_address(lib_fd, &elf_ehdr);
print_debug("reading library %s @ 0x%lx [ 0x%lx ]\n",
lib_name, lib_base, lib_base_diff);