diff options
Diffstat (limited to 'src/os/solaris/fix_empty_sec_hdr_flags/fix_empty_sec_hdr_flags.c')
| -rw-r--r-- | src/os/solaris/fix_empty_sec_hdr_flags/fix_empty_sec_hdr_flags.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/src/os/solaris/fix_empty_sec_hdr_flags/fix_empty_sec_hdr_flags.c b/src/os/solaris/fix_empty_sec_hdr_flags/fix_empty_sec_hdr_flags.c new file mode 100644 index 000000000..6582d9506 --- /dev/null +++ b/src/os/solaris/fix_empty_sec_hdr_flags/fix_empty_sec_hdr_flags.c @@ -0,0 +1,181 @@ +/* + * 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); +} |