Signed-off-by: Richard Henderson <r...@twiddle.net>
---
linux-user/elfload.c | 201 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 193 insertions(+), 8 deletions(-)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 100efdc..7b854e2 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -183,6 +183,8 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs,
const CPUState *env)
(*regs)[26] = env->segs[R_GS].selector & 0xffff;
}
+#define VDSO_BASENAME "vdso-linux-x64.so"
+
#else
#define ELF_START_MMAP 0x80000000
@@ -801,6 +803,10 @@ static inline void init_thread(struct target_pt_regs *regs,
#define ELF_HWCAP 0
#endif
+#ifndef VDSO_BASENAME
+#define VDSO_BASENAME NULL
+#endif
+
#ifdef TARGET_ABI32
#undef ELF_CLASS
#define ELF_CLASS ELFCLASS32
@@ -1077,7 +1083,8 @@ static void zero_bss(abi_ulong elf_bss, abi_ulong
last_bss, int prot)
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;
int size;
@@ -1100,16 +1107,21 @@ static abi_ulong create_elf_tables(abi_ulong p, int
argc, int envc,
*/
sp = sp &~ (abi_ulong)15;
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
size += envc + argc + 2;
size += 1; /* argc itself */
size *= n;
- if (size & 15)
+ if (size & 15) {
sp -= 16 - (size & 15);
+ }
/* This is correct because Linux defines
* elf_addr_t as Elf32_Off / Elf64_Off
@@ -1126,7 +1138,9 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc,
int envc,
NEW_AUX_ENT(AT_PHENT, (abi_ulong)(sizeof (struct elf_phdr)));
NEW_AUX_ENT(AT_PHNUM, (abi_ulong)(exec->e_phnum));
NEW_AUX_ENT(AT_PAGESZ, (abi_ulong)(TARGET_PAGE_SIZE));
- NEW_AUX_ENT(AT_BASE, (abi_ulong)(interp_info->load_addr));
+ if (interp_info) {
+ NEW_AUX_ENT(AT_BASE, (abi_ulong)(interp_info->load_addr));
+ }
NEW_AUX_ENT(AT_FLAGS, (abi_ulong)0);
NEW_AUX_ENT(AT_ENTRY, info->entry);
NEW_AUX_ENT(AT_UID, (abi_ulong) getuid());
@@ -1135,8 +1149,13 @@ static abi_ulong create_elf_tables(abi_ulong p, int
argc, int envc,
NEW_AUX_ENT(AT_EGID, (abi_ulong) getegid());
NEW_AUX_ENT(AT_HWCAP, (abi_ulong) ELF_HWCAP);
NEW_AUX_ENT(AT_CLKTCK, (abi_ulong) sysconf(_SC_CLK_TCK));
- if (k_platform)
+ if (k_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);
+ }
#ifdef ARCH_DLINFO
/*
* ARCH_DLINFO must come last so platform specific code can enforce
@@ -1378,6 +1397,165 @@ 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 = alloca(strlen(CONFIG_QEMU_SHAREDIR "/") + strlen(basename) + 1);
+ stpcpy(stpcpy(filename, CONFIG_QEMU_SHAREDIR "/"), basename);
+
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ goto exit_perror;
+ }
+
+ 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)
{
struct elf_sym *key = (struct elf_sym *)s0;
@@ -1512,7 +1690,7 @@ static void load_symbols(struct elfhdr *hdr, int fd,
abi_ulong load_bias)
int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
struct image_info * info)
{
- struct image_info interp_info;
+ struct image_info interp_info, vdso_info;
struct elfhdr elf_ex;
char *elf_interpreter = NULL;
@@ -1559,8 +1737,15 @@ int load_elf_binary(struct linux_binprm * bprm, struct
target_pt_regs * regs,
}
}
- 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.
--
1.6.6.1
