From a28b18fa16edaeb6bc7d34cf1ddac690b27ba610 Mon Sep 17 00:00:00 2001 From: Thomas Preud'homme Date: Mon, 26 Apr 2010 00:46:39 +0200 Subject: [PATCH] Link alias symbols together Make sure alias symbols resolve to the same address in program .bss or .data section. This ensure for example that if a program reference environ (via an extern char **environ declaration) and the libc change its value via the __environ alias after the R_ARCH_COPY relocation have been performed, then the program will see the new value. --- tccelf.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/tccelf.c b/tccelf.c index a35206e..91a203e 100644 --- a/tccelf.c +++ b/tccelf.c @@ -1510,12 +1510,32 @@ static int elf_output_file(TCCState *s1, const char *filename) sym - (ElfW(Sym) *)symtab_section->data); } else if (type == STT_OBJECT) { unsigned long offset; + ElfW(Sym) *dynsym, *dynsym_end; offset = bss_section->data_offset; /* XXX: which alignment ? */ offset = (offset + 16 - 1) & -16; index = put_elf_sym(s1->dynsym, offset, esym->st_size, esym->st_info, 0, bss_section->sh_num, name); + /* Ensure symbol aliases (that is, symbols with + the same st_value) resolve to the same + address in program .bss or .data section. */ + dynsym_end = (ElfW(Sym) *) + (s1->dynsymtab_section->data + + s1->dynsymtab_section->data_offset); + for(dynsym = (ElfW(Sym) *)s1->dynsymtab_section->data + 1; + dynsym < dynsym_end; dynsym++) { + if (dynsym->st_value == esym->st_value) { + char *dynname; + dynname = s1->dynsymtab_section->link->data + + dynsym->st_name; + put_elf_sym(s1->dynsym, offset, + dynsym->st_size, + dynsym->st_info, 0, + bss_section->sh_num, + dynname); + } + } put_elf_reloc(s1->dynsym, bss_section, offset, R_COPY, index); offset += esym->st_size;