From e020e387b3da272ef9750bad5f585119cbaf3871 Mon Sep 17 00:00:00 2001 From: "howard_b_golden@yahoo.com" Date: Wed, 16 Dec 2009 18:51:55 +0000 Subject: [PATCH] FIX #2615 (linker scripts in .so files) This patch does not apply to Windows. It only applies to systems with ELF binaries. This is a patch to rts/Linker.c to recognize linker scripts in .so files and find the real target .so shared library for loading. --- rts/Linker.c | 149 ++++++++++++++++++++++++++++++++++++++++++++----- rts/LinkerInternals.h | 2 + rts/RtsStartup.c | 4 ++ 3 files changed, 140 insertions(+), 15 deletions(-) diff --git a/rts/Linker.c b/rts/Linker.c index d12c6fc..3b419f2 100644 --- a/rts/Linker.c +++ b/rts/Linker.c @@ -39,6 +39,8 @@ #include #include +#include +#include #ifdef HAVE_SYS_STAT_H #include @@ -79,6 +81,8 @@ #if defined(linux_HOST_OS) || defined(solaris2_HOST_OS) || defined(freebsd_HOST_OS) || defined(dragonfly_HOST_OS) || defined(netbsd_HOST_OS) || defined(openbsd_HOST_OS) # define OBJFORMAT_ELF +# include // regex is already used by dlopen() so this is OK + // to use here without requiring an additional lib #elif defined(cygwin32_HOST_OS) || defined (mingw32_HOST_OS) # define OBJFORMAT_PEi386 # include @@ -1095,12 +1099,19 @@ static int linker_init_done = 0 ; #if defined(OBJFORMAT_ELF) || defined(OBJFORMAT_MACHO) static void *dl_prog_handle; +static regex_t re_invalid; +static regex_t re_realso; +static void initLinkerCleanup( void ); +#ifdef THREADED_RTS +static Mutex dl_mutex; // mutex to protect dlopen/dlerror critical section +#endif #endif void initLinker( void ) { RtsSymbolVal *sym; + int compileResult; /* Make initLinker idempotent, so we can call it before evey relevant operation; that means we @@ -1109,6 +1120,9 @@ initLinker( void ) linker_init_done = 1; } +#ifdef THREADED_RTS + initMutex(&dl_mutex); +#endif stablehash = allocStrHashTable(); symhash = allocStrHashTable(); @@ -1127,6 +1141,15 @@ initLinker( void ) # else dl_prog_handle = dlopen(NULL, RTLD_LAZY); # endif /* RTLD_DEFAULT */ + + compileResult = regcomp(&re_invalid, + "(([^ \t()])+\\.so([^ \t:()])*):([ \t])*invalid ELF header", + REG_EXTENDED); + ASSERT( compileResult == 0 ); + compileResult = regcomp(&re_realso, + "GROUP *\\( *(([^ )])+)", + REG_EXTENDED); + ASSERT( compileResult == 0 ); # endif #if defined(x86_64_HOST_ARCH) @@ -1147,6 +1170,19 @@ initLinker( void ) #endif } +void +exitLinker( void ) { +#if defined(OBJFORMAT_ELF) || defined(OBJFORMAT_MACHO) + if (linker_init_done == 1) { + regfree(&re_invalid); + regfree(&re_realso); +#ifdef THREADED_RTS + closeMutex(&dl_mutex); +#endif + } +#endif +} + /* ----------------------------------------------------------------------------- * Loading DLL or .so dynamic libraries * ----------------------------------------------------------------------------- @@ -1182,29 +1218,112 @@ typedef static OpenedDLL* opened_dlls = NULL; #endif -const char * -addDLL( char *dll_name ) -{ # if defined(OBJFORMAT_ELF) || defined(OBJFORMAT_MACHO) - /* ------------------- ELF DLL loader ------------------- */ - void *hdl; - const char *errmsg; - initLinker(); +static char * +internal_dlopen(const char *dll_name) +{ + void *hdl; + char *errmsg, *errmsg_copy; // omitted: RTLD_NOW // see http://www.haskell.org/pipermail/cvs-ghc/2007-September/038570.html - hdl= dlopen(dll_name, RTLD_LAZY | RTLD_GLOBAL); + IF_DEBUG(linker, + debugBelch("internal_dlopen: dll_name = '%s'\n", dll_name)); + //-------------- Begin critical section ------------------ + // This critical section is necessary because dlerror() is not + // required to be reentrant (see POSIX -- IEEE Std 1003.1-2008) + // Also, the error message returned must be copied to preserve it + // (see POSIX also) + + ACQUIRE_LOCK(&dl_mutex); + hdl = dlopen(dll_name, RTLD_LAZY | RTLD_GLOBAL); + + errmsg = NULL; if (hdl == NULL) { /* dlopen failed; return a ptr to the error msg. */ errmsg = dlerror(); if (errmsg == NULL) errmsg = "addDLL: unknown error"; - return errmsg; - } else { + errmsg_copy = stgMallocBytes(strlen(errmsg)+1, "addDLL"); + strcpy(errmsg_copy, errmsg); + errmsg = errmsg_copy; + } + RELEASE_LOCK(&dl_mutex); + //--------------- End critical section ------------------- + + return errmsg; +} +# endif + +const char * +addDLL( char *dll_name ) +{ +# if defined(OBJFORMAT_ELF) || defined(OBJFORMAT_MACHO) + /* ------------------- ELF DLL loader ------------------- */ + +#define NMATCH 5 + regmatch_t match[NMATCH]; + char *errmsg; + FILE* fp; + size_t match_length; +#define MAXLINE 1000 + char line[MAXLINE]; + int result; + + initLinker(); + + IF_DEBUG(linker, debugBelch("addDLL: dll_name = '%s'\n", dll_name)); + errmsg = internal_dlopen(dll_name); + + if (errmsg == NULL) { return NULL; } - /*NOTREACHED*/ + + // GHC Trac ticket #2615 + // On some systems (e.g., Gentoo Linux) dynamic files (e.g. libc.so) + // contain linker scripts rather than ELF-format object code. This + // code handles the situation by recognizing the real object code + // file name given in the linker script. + // + // If an "invalid ELF header" error occurs, it is assumed that the + // .so file contains a linker script instead of ELF object code. + // In this case, the code looks for the GROUP ( ... ) linker + // directive. If one is found, the first file name inside the + // parentheses is treated as the name of a dynamic library and the + // code attempts to dlopen that file. If this is also unsuccessful, + // an error message is returned. + + // see if the error message is due to an invalid ELF header + IF_DEBUG(linker, debugBelch("errmsg = '%s'\n", errmsg)); + result = regexec(&re_invalid, errmsg, (size_t) NMATCH, match, 0); + IF_DEBUG(linker, debugBelch("result = %i\n", result)); + if (result == 0) { + // success -- try to read the named file as a linker script + match_length = (size_t) stg_min((match[1].rm_eo - match[1].rm_so), + MAXLINE-1); + strncpy(line, (errmsg+(match[1].rm_so)),match_length); + line[match_length] = '\0'; // make sure string is null-terminated + IF_DEBUG(linker, debugBelch ("file name = '%s'\n", line)); + if ((fp = fopen(line, "r")) == NULL) { + return errmsg; // return original error if open fails + } + // try to find a GROUP ( ... ) command + while (fgets(line, MAXLINE, fp) != NULL) { + IF_DEBUG(linker, debugBelch("input line = %s", line)); + if (regexec(&re_realso, line, (size_t) NMATCH, match, 0) == 0) { + // success -- try to dlopen the first named file + IF_DEBUG(linker, debugBelch("match%s\n","")); + line[match[1].rm_eo] = '\0'; + errmsg = internal_dlopen(line+match[1].rm_so); + break; + } + // if control reaches here, no GROUP ( ... ) directive was found + // and the original error message is returned to the caller + } + fclose(fp); + } + return errmsg; # elif defined(OBJFORMAT_PEi386) /* ------------------- Win32 DLL loader ------------------- */ @@ -4195,7 +4314,7 @@ static int relocateSection( i++; } #endif - else + else { barf ("Don't know how to handle this Mach-O " "scattered relocation entry: " @@ -4204,7 +4323,7 @@ static int relocateSection( oc->fileName, scat->r_type, scat->r_address); return 0; } - + #ifdef powerpc_HOST_ARCH if(scat->r_type == GENERIC_RELOC_VANILLA || scat->r_type == PPC_RELOC_SECTDIFF) @@ -4250,8 +4369,8 @@ static int relocateSection( "object file %s; entry type %ld; address %#lx\n", oc->fileName, scat->r_type, scat->r_address); return 0; - } - + } + } else /* !(relocs[i].r_address & R_SCATTERED) */ { diff --git a/rts/LinkerInternals.h b/rts/LinkerInternals.h index 561a224..8dc6441 100644 --- a/rts/LinkerInternals.h +++ b/rts/LinkerInternals.h @@ -109,4 +109,6 @@ typedef struct _ObjectCode { extern ObjectCode *objects; +void exitLinker( void ); + #endif /* LINKERINTERNALS_H */ diff --git a/rts/RtsStartup.c b/rts/RtsStartup.c index b85b153..6a01e85 100644 --- a/rts/RtsStartup.c +++ b/rts/RtsStartup.c @@ -34,6 +34,7 @@ #include "Profiling.h" #include "Timer.h" #include "Globals.h" +void exitLinker( void ); // there is no Linker.h file to include #if defined(RTS_GTK_FRONTPANEL) #include "FrontPanel.h" @@ -388,6 +389,9 @@ hs_exit_(rtsBool wait_foreign) /* free shared Typeable store */ exitGlobalStore(); + /* free linker data */ + exitLinker(); + /* free file locking tables, if necessary */ #if !defined(mingw32_HOST_OS) freeFileLocking(); -- 1.7.10.4