Mercurial > hg > truffle
view src/os/solaris/fix_empty_sec_hdr_flags/fix_empty_sec_hdr_flags.c @ 20295:3f2894c5052e
8048112: G1 Full GC needs to support the case when the very first region is not available
Summary: Refactor preparation for compaction during Full GC so that it lazily initializes the first compaction point. This also avoids problems later when the first region may not be committed. Also reviewed by K. Barrett.
Reviewed-by: brutisso
author | tschatzl |
---|---|
date | Mon, 21 Jul 2014 10:00:31 +0200 |
parents | 9c1709c4c80c |
children |
line wrap: on
line source
/* * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ /* * Name: fix_empty_sec_hdr_flags.c * * Description: Remove the SHF_ALLOC flag from "empty" section headers. * An "empty" section header has sh_addr == 0 and sh_size == 0. * * This program is adapted from the example program shown on the * elf(3elf) man page and from code from the Solaris compiler * driver. */ #include <fcntl.h> #include <stdio.h> #include <libelf.h> #include <stdlib.h> #include <string.h> #include <unistd.h> static void failure(void); void main(int argc, char ** argv) { void * ehdr; /* ELF header */ unsigned int i; /* section counter */ int fd; /* descriptor for file */ Elf * elf; /* ELF descriptor */ char * elf_ident; /* ELF identity string */ char * elf_obj; /* elf_obj file */ int fix_count; /* number of flags fixed */ int is_elfclass64; /* is an ELFCLASS64 file? */ Elf_Scn * scn; /* ELF section descriptor */ void * shdr; /* ELF section header */ Elf_Data * shstrtab; /* ELF section header string table */ if (argc != 2) { (void) fprintf(stderr, "Usage: %s elf_obj\n", argv[0]); exit(2); } /* open the elf_obj */ elf_obj = argv[1]; if ((fd = open(elf_obj, O_RDWR)) == -1) { (void) fprintf(stderr, "%s: cannot open file.\n", elf_obj); exit(3); } (void) printf("Opening '%s' for update\n", elf_obj); (void) fflush(stdout); (void) elf_version(EV_CURRENT); /* coordinate ELF versions */ /* obtain the ELF descriptors from the input file */ if ((elf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL) { failure(); } /* determine if ELFCLASS64 or not? */ elf_ident = elf_getident(elf, NULL); is_elfclass64 = (elf_ident[EI_CLASS] == ELFCLASS64); /* get the ELF header */ if (is_elfclass64) { ehdr = elf64_getehdr(elf); } else { ehdr = elf32_getehdr(elf); } if (ehdr == NULL) { failure(); } /* get the ELF section descriptor */ if (is_elfclass64) { scn = elf_getscn(elf, ((Elf64_Ehdr *) ehdr)->e_shstrndx); } else { scn = elf_getscn(elf, ((Elf32_Ehdr *) ehdr)->e_shstrndx); } if (scn == NULL) { failure(); } /* get the section header string table */ shstrtab = elf_getdata(scn, NULL); if (shstrtab == NULL) { failure(); } fix_count = 0; /* traverse the sections of the input file */ for (i = 1, scn = NULL; scn = elf_nextscn(elf, scn); i++) { int has_flag_set; /* is SHF_ALLOC flag set? */ int is_empty; /* is section empty? */ char * name; /* short hand pointer */ /* get the section header */ if (is_elfclass64) { shdr = elf64_getshdr(scn); } else { shdr = elf32_getshdr(scn); } if (shdr == NULL) { failure(); } if (is_elfclass64) { name = (char *)shstrtab->d_buf + ((Elf64_Shdr *) shdr)->sh_name; } else { name = (char *)shstrtab->d_buf + ((Elf32_Shdr *) shdr)->sh_name; } if (is_elfclass64) { has_flag_set = ((Elf64_Shdr *) shdr)->sh_flags & SHF_ALLOC; is_empty = ((Elf64_Shdr *) shdr)->sh_addr == 0 && ((Elf64_Shdr *) shdr)->sh_size == 0; } else { has_flag_set = ((Elf32_Shdr *) shdr)->sh_flags & SHF_ALLOC; is_empty = ((Elf32_Shdr *) shdr)->sh_addr == 0 && ((Elf32_Shdr *) shdr)->sh_size == 0; } if (is_empty && has_flag_set) { (void) printf("section[%u] '%s' is empty, " "but SHF_ALLOC flag is set.\n", i, name); (void) printf("Clearing the SHF_ALLOC flag.\n"); if (is_elfclass64) { ((Elf64_Shdr *) shdr)->sh_flags &= ~SHF_ALLOC; } else { ((Elf32_Shdr *) shdr)->sh_flags &= ~SHF_ALLOC; } fix_count++; } } /* end for each ELF section */ if (fix_count > 0) { (void) printf("Saving %d updates to '%s'\n", fix_count, elf_obj); (void) fflush(stdout); (void) elf_update(elf, ELF_C_NULL); /* recalc ELF memory structures */ (void) elf_update(elf, ELF_C_WRITE); /* write out changes to ELF obj */ } else { (void) printf("No SHF_ALLOC flags needed to be cleared.\n"); } (void) elf_end(elf); /* done with ELF obj */ (void) close(fd); (void) printf("Done %s '%s'\n", (fix_count > 0) ? "updating" : "with", elf_obj); (void) fflush(stdout); exit(0); } /* end main */ static void failure() { (void) fprintf(stderr, "%s\n", elf_errmsg(elf_errno())); exit(6); }