@@ -199,6 +199,8 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUX86State *en
(*regs)[26] = env->segs[R_GS].selector & 0xffff;
}
+#define VDSO_BASENAME "vdso-linux-x64.so"
+
#else
#define ELF_START_MMAP 0x80000000
@@ -1499,6 +1501,10 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs,
#define STACK_ALIGNMENT 16
#endif
+#ifndef VDSO_BASENAME
+#define VDSO_BASENAME NULL
+#endif
+
#ifdef TARGET_ABI32
#undef ELF_CLASS
#define ELF_CLASS ELFCLASS32
@@ -1859,7 +1865,8 @@ static abi_ulong loader_build_fdpic_loadmap(struct image_info *info, abi_ulong s
static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
struct elfhdr *exec,
struct image_info *info,
- struct image_info *interp_info)
+ struct image_info *interp_info,
+ struct image_info *vdso_info)
{
abi_ulong sp;
abi_ulong u_argc, u_argv, u_envp, u_auxv;
@@ -1931,8 +1938,12 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
}
size = (DLINFO_ITEMS + 1) * 2;
- if (k_platform)
+ if (k_platform) {
size += 2;
+ }
+ if (vdso_info) {
+ size += 4;
+ }
#ifdef DLINFO_ARCH_ITEMS
size += DLINFO_ARCH_ITEMS * 2;
#endif
@@ -2009,6 +2020,10 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
if (u_platform) {
NEW_AUX_ENT(AT_PLATFORM, u_platform);
}
+ if (vdso_info) {
+ NEW_AUX_ENT(AT_SYSINFO, vdso_info->entry);
+ NEW_AUX_ENT(AT_SYSINFO_EHDR, vdso_info->load_addr);
+ }
NEW_AUX_ENT (AT_NULL, 0);
#undef NEW_AUX_ENT
@@ -2614,6 +2629,177 @@ static void load_elf_interp(const char *filename, struct image_info *info,
exit(-1);
}
+static void load_elf_vdso(const char *basename, struct image_info *info,
+ char bprm_buf[BPRM_BUF_SIZE])
+{
+ const char *errmsg;
+ char *filename;
+ int fd, retval, i;
+ abi_ulong load_bias;
+
+ /*
+ * ??? What we really need access to is qemu_find_file, but that is
+ * only built for system targets at the moment.
+ */
+ filename = g_build_filename(CONFIG_QEMU_DATADIR, basename, NULL);
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ goto exit_perror;
+ }
+ g_free(filename);
+
+ retval = read(fd, bprm_buf, BPRM_BUF_SIZE);
+ if (retval < 0) {
+ goto exit_perror;
+ }
+ if (retval < BPRM_BUF_SIZE) {
+ memset(bprm_buf + retval, 0, BPRM_BUF_SIZE - retval);
+ }
+
+ load_elf_image(basename, fd, info, NULL, bprm_buf);
+ load_bias = info->load_bias;
+
+ /*
+ * We most likely need to relocate the VDSO image. The one built into
+ * the kernel is built for a fixed address. The one built for QEMU is
+ * not, since that requires close control of the guest address space.
+ */
+ if (load_bias) {
+ struct elfhdr *ehdr = (struct elfhdr *)bprm_buf;
+ struct elf_phdr *phdr;
+ abi_ulong dynamic_addr = -1;
+ abi_ulong dynsym_addr = -1;
+
+ /*
+ * ??? Assume QEMU's VDSO is built "properly", which arranges
+ * for the PHDRs, and all the sections manipulated below, to
+ * be included with a writable load segment.
+ *
+ * ??? One might think that we'd need to relocate ehdr.e_entry,
+ * but for some reason glibc does that one itself, though that
+ * is also available via the AT_SYSINFO entry.
+ */
+
+ /* Relocate the program headers. */
+ phdr = (struct elf_phdr *)g2h(info->load_addr + ehdr->e_phoff);
+ bswap_phdr(phdr, ehdr->e_phnum);
+ for (i = 0; i < ehdr->e_phnum; ++i) {
+ phdr[i].p_vaddr += load_bias;
+ phdr[i].p_paddr += load_bias;
+ if (phdr[i].p_type == PT_DYNAMIC) {
+ dynamic_addr = phdr[i].p_vaddr;
+ }
+ }
+ bswap_phdr(phdr, ehdr->e_phnum);
+
+ /* Relocate the DYNAMIC entries. */
+ if (dynamic_addr != -1) {
+ abi_ulong tag, val, *dyn = (abi_ulong *)g2h(dynamic_addr);
+ do {
+ tag = tswapl(dyn[0]);
+ val = tswapl(dyn[1]);
+ switch (tag) {
+ case DT_SYMTAB:
+ dynsym_addr = load_bias + val;
+ dyn[1] = tswapl(dynsym_addr);
+ break;
+ case DT_SYMENT:
+ if (val != sizeof(struct elf_sym)) {
+ errmsg = "VDSO has an unexpected dynamic symbol size";
+ goto exit_errmsg;
+ }
+ break;
+
+ case DT_HASH:
+ case DT_STRTAB:
+ case DT_VERDEF:
+ case DT_VERSYM:
+ case DT_ADDRRNGLO ... DT_ADDRRNGHI:
+ /* These entries store an address in the entry. */
+ dyn[1] = tswapl(load_bias + val);
+ break;
+
+ case DT_NULL:
+ case DT_STRSZ:
+ case DT_SONAME:
+ case DT_DEBUG:
+ case DT_FLAGS:
+ case DT_FLAGS_1:
+ case DT_VERDEFNUM:
+ case DT_VALRNGLO ... DT_VALRNGHI:
+ /* These entries store an integer in the entry. */
+ break;
+
+ case DT_REL:
+ case DT_RELA:
+ /*
+ * These entries indicate that the VDSO was built
+ * incorrectly. It should not have real relocations.
+ */
+ errmsg = "VDSO has relocations";
+ goto exit_errmsg;
+ case DT_NEEDED:
+ case DT_VERNEED:
+ errmsg = "VDSO has external dependancies";
+ goto exit_errmsg;
+
+ default:
+ /* This is probably something target specific. */
+ errmsg = "VDSO has unknown DYNAMIC entry";
+ goto exit_errmsg;
+ }
+ dyn += 2;
+ } while (tag != DT_NULL);
+ }
+
+ /* Relocate the dynamic symbol table. */
+ if (dynsym_addr != -1) {
+ struct elf_shdr *shdr;
+ struct elf_sym *sym;
+ int dynsym_size = 0;
+
+ /*
+ * Read the section headers to find out the size of the
+ * dynamic symbol table.
+ */
+ shdr = (struct elf_shdr *)g2h(info->load_addr + ehdr->e_shoff);
+ for (i = 0; i < ehdr->e_shnum; ++i) {
+ abi_ulong addr = tswapl(shdr[i].sh_addr) + load_bias;
+ if (addr == dynsym_addr) {
+ dynsym_size = tswapl(shdr[i].sh_size);
+ break;
+ }
+ }
+
+ sym = (struct elf_sym *)g2h(dynsym_addr);
+ for (i = 0; i < dynsym_size / sizeof(*sym); ++i) {
+ sym[i].st_value = tswapl(tswapl(sym[i].st_value) + load_bias);
+ }
+ }
+ }
+
+ /*
+ * Mark the VDSO writable segment read-only.
+ *
+ * ??? This assumes that the VDSO implementation doesn't actually
+ * have any truely writable data. Perhaps we should instead use
+ * the PT_GNU_RELRO header to indicate that we really want this.
+ */
+ retval = target_mprotect(info->start_data, info->brk - info->start_data,
+ PROT_READ);
+ if (retval < 0) {
+ goto exit_perror;
+ }
+ return;
+
+ exit_perror:
+ errmsg = strerror(errno);
+ exit_errmsg:
+ fprintf(stderr, "%s: %s\n", filename, errmsg);
+ exit(-1);
+}
+
+
static int symfind(const void *s0, const void *s1)
{
target_ulong addr = *(target_ulong *)s0;
@@ -2803,7 +2989,7 @@ uint32_t get_elf_eflags(int fd)
int load_elf_binary(struct linux_binprm *bprm, struct image_info *info)
{
- struct image_info interp_info;
+ struct image_info interp_info, vdso_info;
struct elfhdr elf_ex;
char *elf_interpreter = NULL;
char *scratch;
@@ -2879,8 +3065,15 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info)
#endif
}
- bprm->p = create_elf_tables(bprm->p, bprm->argc, bprm->envc, &elf_ex,
- info, (elf_interpreter ? &interp_info : NULL));
+ /* If we've been given a VDSO to load, do so. */
+ if (VDSO_BASENAME) {
+ load_elf_vdso(VDSO_BASENAME, &vdso_info, bprm->buf);
+ }
+
+ bprm->p = create_elf_tables(bprm->p, bprm->argc, bprm->envc,
+ &elf_ex, info,
+ (elf_interpreter ? &interp_info : NULL),
+ (VDSO_BASENAME ? &vdso_info : NULL));
info->start_stack = bprm->p;
/* If we have an interpreter, set that as the program's entry point.