[Git][ghc/ghc][wip/unloading-fixes] 2 commits: rts/linker: Move shared library loading logic into Elf.c
Ben Gamari
gitlab at gitlab.haskell.org
Fri Nov 27 18:01:47 UTC 2020
Ben Gamari pushed to branch wip/unloading-fixes at Glasgow Haskell Compiler / GHC
Commits:
0fd2288e by Ben Gamari at 2020-11-27T18:01:19+00:00
rts/linker: Move shared library loading logic into Elf.c
- - - - -
ea36515e by GHC GitLab CI at 2020-11-27T18:01:19+00:00
rts/linker: Don't declare dynamic objects with image_mapped
This previously resulted in warnings due to spurious unmap failures.
- - - - -
4 changed files:
- rts/Linker.c
- rts/LinkerInternals.h
- rts/linker/Elf.c
- rts/linker/Elf.h
Changes:
=====================================
rts/Linker.c
=====================================
@@ -64,7 +64,6 @@
# include "linker/Elf.h"
# include <regex.h> // regex is already used by dlopen() so this is OK
// to use here without requiring an additional lib
-# include <link.h>
#elif defined(OBJFORMAT_PEi386)
# include "linker/PEi386.h"
# include <windows.h>
@@ -171,8 +170,6 @@ Mutex linker_mutex;
/* Generic wrapper function to try and Resolve and RunInit oc files */
int ocTryLoad( ObjectCode* oc );
-static void freeNativeCode_ELF (ObjectCode *nc);
-
/* Link objects into the lower 2Gb on x86_64 and AArch64. GHC assumes the
* small memory model on this architecture (see gcc docs,
* -mcmodel=small).
@@ -399,7 +396,7 @@ static void *dl_prog_handle;
static regex_t re_invalid;
static regex_t re_realso;
#if defined(THREADED_RTS)
-static Mutex dl_mutex; // mutex to protect dlopen/dlerror critical section
+Mutex dl_mutex; // mutex to protect dlopen/dlerror critical section
#endif
#endif
@@ -1871,7 +1868,7 @@ HsInt purgeObj (pathchar *path)
return r;
}
-static OStatus getObjectLoadStatus_ (pathchar *path)
+OStatus getObjectLoadStatus_ (pathchar *path)
{
for (ObjectCode *o = objects; o; o = o->next) {
if (0 == pathcmp(o->fileName, path)) {
@@ -1961,141 +1958,6 @@ addSection (Section *s, SectionKind kind, SectionAlloc alloc,
size, kind ));
}
-
-# if defined(OBJFORMAT_ELF)
-static int loadNativeObjCb_(struct dl_phdr_info *info,
- size_t _size GNUC3_ATTRIBUTE(__unused__), void *data) {
- ObjectCode* nc = (ObjectCode*) data;
-
- // This logic mimicks _dl_addr_inside_object from glibc
- // For reference:
- // int
- // internal_function
- // _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
- // {
- // int n = l->l_phnum;
- // const ElfW(Addr) reladdr = addr - l->l_addr;
- //
- // while (--n >= 0)
- // if (l->l_phdr[n].p_type == PT_LOAD
- // && reladdr - l->l_phdr[n].p_vaddr >= 0
- // && reladdr - l->l_phdr[n].p_vaddr < l->l_phdr[n].p_memsz)
- // return 1;
- // return 0;
- // }
-
- if ((void*) info->dlpi_addr == nc->l_addr) {
- int n = info->dlpi_phnum;
- while (--n >= 0) {
- if (info->dlpi_phdr[n].p_type == PT_LOAD) {
- NativeCodeRange* ncr =
- stgMallocBytes(sizeof(NativeCodeRange), "loadNativeObjCb_");
- ncr->start = (void*) ((char*) nc->l_addr + info->dlpi_phdr[n].p_vaddr);
- ncr->end = (void*) ((char*) ncr->start + info->dlpi_phdr[n].p_memsz);
-
- ncr->next = nc->nc_ranges;
- nc->nc_ranges = ncr;
- }
- }
- }
- return 0;
-}
-
-static void copyErrmsg(char** errmsg_dest, char* errmsg) {
- if (errmsg == NULL) errmsg = "loadNativeObj_ELF: unknown error";
- *errmsg_dest = stgMallocBytes(strlen(errmsg)+1, "loadNativeObj_ELF");
- strcpy(*errmsg_dest, errmsg);
-}
-
-// need dl_mutex
-static void freeNativeCode_ELF (ObjectCode *nc) {
- dlclose(nc->dlopen_handle);
-
- NativeCodeRange *ncr = nc->nc_ranges;
- while (ncr) {
- NativeCodeRange* last_ncr = ncr;
- ncr = ncr->next;
- stgFree(last_ncr);
- }
-}
-
-static void * loadNativeObj_ELF (pathchar *path, char **errmsg)
-{
- ObjectCode* nc;
- void *hdl, *retval;
-
- IF_DEBUG(linker, debugBelch("loadNativeObj_ELF %" PATH_FMT "\n", path));
-
- retval = NULL;
- ACQUIRE_LOCK(&dl_mutex);
-
- /* Loading the same object multiple times will lead to chaos
- * as we will have two ObjectCodes but one underlying dlopen
- * handle. Fail if this happens.
- */
- if (getObjectLoadStatus_(path) != OBJECT_NOT_LOADED) {
- copyErrmsg(errmsg, "loadNativeObj_ELF: Already loaded");
- goto dlopen_fail;
- }
-
- nc = mkOc(DYNAMIC_OBJECT, path, NULL, 0, true, NULL, 0);
-
- foreignExportsLoadingObject(nc);
- hdl = dlopen(path, RTLD_NOW|RTLD_LOCAL);
- foreignExportsFinishedLoadingObject();
- if (hdl == NULL) {
- /* dlopen failed; save the message in errmsg */
- copyErrmsg(errmsg, dlerror());
- goto dlopen_fail;
- }
-
- struct link_map *map;
- if (dlinfo(hdl, RTLD_DI_LINKMAP, &map) == -1) {
- /* dlinfo failed; save the message in errmsg */
- copyErrmsg(errmsg, dlerror());
- goto dlinfo_fail;
- }
-
- nc->l_addr = (void*) map->l_addr;
- nc->dlopen_handle = hdl;
- hdl = NULL; // pass handle ownership to nc
-
- dl_iterate_phdr(loadNativeObjCb_, nc);
- if (!nc->nc_ranges) {
- copyErrmsg(errmsg, "dl_iterate_phdr failed to find obj");
- goto dl_iterate_phdr_fail;
- }
-
- insertOCSectionIndices(nc);
-
- nc->next_loaded_object = loaded_objects;
- loaded_objects = nc;
-
- retval = nc->dlopen_handle;
-
-#if defined(PROFILING)
- // collect any new cost centres that were defined in the loaded object.
- refreshProfilingCCSs();
-#endif
-
- goto success;
-
-dl_iterate_phdr_fail:
- // already have dl_mutex
- freeNativeCode_ELF(nc);
-dlinfo_fail:
- if (hdl) dlclose(hdl);
-dlopen_fail:
-success:
-
- RELEASE_LOCK(&dl_mutex);
- IF_DEBUG(linker, debugBelch("loadNativeObj_ELF result=%p\n", retval));
-
- return retval;
-}
-
-# endif
-
#define UNUSED(x) (void)(x)
void * loadNativeObj (pathchar *path, char **errmsg)
=====================================
rts/LinkerInternals.h
=====================================
@@ -306,6 +306,10 @@ typedef struct _ObjectCode {
#if defined(THREADED_RTS)
extern Mutex linker_mutex;
+
+#if defined(OBJFORMAT_ELF) || defined(OBJFORMAT_MACHO)
+extern Mutex dl_mutex;
+#endif
#endif
/* Type of the initializer */
@@ -388,6 +392,7 @@ resolveSymbolAddr (pathchar* buffer, int size,
#endif
HsInt isAlreadyLoaded( pathchar *path );
+OStatus getObjectLoadStatus_ (pathchar *path);
HsInt loadOc( ObjectCode* oc );
ObjectCode* mkOc( ObjectType type, pathchar *path, char *image, int imageSize,
bool mapped, pathchar *archiveMemberName,
=====================================
rts/linker/Elf.c
=====================================
@@ -15,15 +15,19 @@
#include "RtsUtils.h"
#include "RtsSymbolInfo.h"
+#include "CheckUnload.h"
+#include "LinkerInternals.h"
#include "linker/Elf.h"
#include "linker/CacheFlush.h"
#include "linker/M32Alloc.h"
#include "linker/SymbolExtras.h"
+#include "ForeignExports.h"
#include "sm/OSMem.h"
#include "GetEnv.h"
#include "linker/util.h"
#include "linker/elf_util.h"
+#include <link.h>
#include <stdlib.h>
#include <string.h>
#if defined(HAVE_SYS_STAT_H)
@@ -1969,6 +1973,143 @@ int ocRunInit_ELF( ObjectCode *oc )
return 1;
}
+/*
+ * Shared object loading
+ */
+
+static int loadNativeObjCb_(struct dl_phdr_info *info,
+ size_t _size GNUC3_ATTRIBUTE(__unused__), void *data) {
+ ObjectCode* nc = (ObjectCode*) data;
+
+ // This logic mimicks _dl_addr_inside_object from glibc
+ // For reference:
+ // int
+ // internal_function
+ // _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
+ // {
+ // int n = l->l_phnum;
+ // const ElfW(Addr) reladdr = addr - l->l_addr;
+ //
+ // while (--n >= 0)
+ // if (l->l_phdr[n].p_type == PT_LOAD
+ // && reladdr - l->l_phdr[n].p_vaddr >= 0
+ // && reladdr - l->l_phdr[n].p_vaddr < l->l_phdr[n].p_memsz)
+ // return 1;
+ // return 0;
+ // }
+
+ if ((void*) info->dlpi_addr == nc->l_addr) {
+ int n = info->dlpi_phnum;
+ while (--n >= 0) {
+ if (info->dlpi_phdr[n].p_type == PT_LOAD) {
+ NativeCodeRange* ncr =
+ stgMallocBytes(sizeof(NativeCodeRange), "loadNativeObjCb_");
+ ncr->start = (void*) ((char*) nc->l_addr + info->dlpi_phdr[n].p_vaddr);
+ ncr->end = (void*) ((char*) ncr->start + info->dlpi_phdr[n].p_memsz);
+
+ ncr->next = nc->nc_ranges;
+ nc->nc_ranges = ncr;
+ }
+ }
+ }
+ return 0;
+}
+
+static void copyErrmsg(char** errmsg_dest, char* errmsg) {
+ if (errmsg == NULL) errmsg = "loadNativeObj_ELF: unknown error";
+ *errmsg_dest = stgMallocBytes(strlen(errmsg)+1, "loadNativeObj_ELF");
+ strcpy(*errmsg_dest, errmsg);
+}
+
+// need dl_mutex
+void freeNativeCode_ELF (ObjectCode *nc) {
+ dlclose(nc->dlopen_handle);
+
+ NativeCodeRange *ncr = nc->nc_ranges;
+ while (ncr) {
+ NativeCodeRange* last_ncr = ncr;
+ ncr = ncr->next;
+ stgFree(last_ncr);
+ }
+}
+
+void * loadNativeObj_ELF (pathchar *path, char **errmsg)
+{
+ ObjectCode* nc;
+ void *hdl, *retval;
+
+ IF_DEBUG(linker, debugBelch("loadNativeObj_ELF %" PATH_FMT "\n", path));
+
+ retval = NULL;
+ ACQUIRE_LOCK(&dl_mutex);
+
+ /* Loading the same object multiple times will lead to chaos
+ * as we will have two ObjectCodes but one underlying dlopen
+ * handle. Fail if this happens.
+ */
+ if (getObjectLoadStatus_(path) != OBJECT_NOT_LOADED) {
+ copyErrmsg(errmsg, "loadNativeObj_ELF: Already loaded");
+ goto dlopen_fail;
+ }
+
+ nc = mkOc(DYNAMIC_OBJECT, path, NULL, 0, false, NULL, 0);
+
+ foreignExportsLoadingObject(nc);
+ hdl = dlopen(path, RTLD_NOW|RTLD_LOCAL);
+ foreignExportsFinishedLoadingObject();
+ if (hdl == NULL) {
+ /* dlopen failed; save the message in errmsg */
+ copyErrmsg(errmsg, dlerror());
+ goto dlopen_fail;
+ }
+
+ struct link_map *map;
+ if (dlinfo(hdl, RTLD_DI_LINKMAP, &map) == -1) {
+ /* dlinfo failed; save the message in errmsg */
+ copyErrmsg(errmsg, dlerror());
+ goto dlinfo_fail;
+ }
+
+ nc->l_addr = (void*) map->l_addr;
+ nc->dlopen_handle = hdl;
+ hdl = NULL; // pass handle ownership to nc
+
+ dl_iterate_phdr(loadNativeObjCb_, nc);
+ if (!nc->nc_ranges) {
+ copyErrmsg(errmsg, "dl_iterate_phdr failed to find obj");
+ goto dl_iterate_phdr_fail;
+ }
+
+ insertOCSectionIndices(nc);
+
+ nc->next_loaded_object = loaded_objects;
+ loaded_objects = nc;
+
+ retval = nc->dlopen_handle;
+
+#if defined(PROFILING)
+ // collect any new cost centres that were defined in the loaded object.
+ refreshProfilingCCSs();
+#endif
+
+ goto success;
+
+dl_iterate_phdr_fail:
+ // already have dl_mutex
+ freeNativeCode_ELF(nc);
+dlinfo_fail:
+ if (hdl) dlclose(hdl);
+dlopen_fail:
+success:
+
+ RELEASE_LOCK(&dl_mutex);
+
+ IF_DEBUG(linker, debugBelch("loadNativeObj_ELF result=%p\n", retval));
+
+ return retval;
+}
+
+
/*
* PowerPC & X86_64 ELF specifics
*/
=====================================
rts/linker/Elf.h
=====================================
@@ -14,5 +14,7 @@ int ocGetNames_ELF ( ObjectCode* oc );
int ocResolve_ELF ( ObjectCode* oc );
int ocRunInit_ELF ( ObjectCode* oc );
int ocAllocateExtras_ELF ( ObjectCode *oc );
+void freeNativeCode_ELF ( ObjectCode *nc );
+void *loadNativeObj_ELF ( pathchar *path, char **errmsg );
#include "EndPrivate.h"
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/28e537b5b86da7a1ea821fd7950650e6aa751658...ea36515eeda8132513fc26d60731b1c6907b5baa
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/28e537b5b86da7a1ea821fd7950650e6aa751658...ea36515eeda8132513fc26d60731b1c6907b5baa
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