1 files changed, 0 insertions, 269 deletions
diff --git a/Documentation/vDSO/parse_vdso.c b/Documentation/vDSO/parse_vdso.c
deleted file mode 100644
index 1dbb4b8..0000000
--- a/Documentation/vDSO/parse_vdso.c
+++ /dev/null
@@ -1,269 +0,0 @@
-/*
- * parse_vdso.c: Linux reference vDSO parser
- * Written by Andrew Lutomirski, 2011-2014.
- *
- * This code is meant to be linked in to various programs that run on Linux.
- * As such, it is available with as few restrictions as possible.  This file
- * is licensed under the Creative Commons Zero License, version 1.0,
- * available at http://creativecommons.org/publicdomain/zero/1.0/legalcode
- *
- * The vDSO is a regular ELF DSO that the kernel maps into user space when
- * it starts a program.  It works equally well in statically and dynamically
- * linked binaries.
- *
- * This code is tested on x86.  In principle it should work on any
- * architecture that has a vDSO.
- */
-
-#include <stdbool.h>
-#include <stdint.h>
-#include <string.h>
-#include <limits.h>
-#include <elf.h>
-
-/*
- * To use this vDSO parser, first call one of the vdso_init_* functions.
- * If you've already parsed auxv, then pass the value of AT_SYSINFO_EHDR
- * to vdso_init_from_sysinfo_ehdr.  Otherwise pass auxv to vdso_init_from_auxv.
- * Then call vdso_sym for each symbol you want.  For example, to look up
- * gettimeofday on x86_64, use:
- *
- *     <some pointer> = vdso_sym("LINUX_2.6", "gettimeofday");
- * or
- *     <some pointer> = vdso_sym("LINUX_2.6", "__vdso_gettimeofday");
- *
- * vdso_sym will return 0 if the symbol doesn't exist or if the init function
- * failed or was not called.  vdso_sym is a little slow, so its return value
- * should be cached.
- *
- * vdso_sym is threadsafe; the init functions are not.
- *
- * These are the prototypes:
- */
-extern void vdso_init_from_auxv(void *auxv);
-extern void vdso_init_from_sysinfo_ehdr(uintptr_t base);
-extern void *vdso_sym(const char *version, const char *name);
-
-
-/* And here's the code. */
-#ifndef ELF_BITS
-# if ULONG_MAX > 0xffffffffUL
-#  define ELF_BITS 64
-# else
-#  define ELF_BITS 32
-# endif
-#endif
-
-#define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x
-#define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x)
-#define ELF(x) ELF_BITS_XFORM(ELF_BITS, x)
-
-static struct vdso_info
-{
-	bool valid;
-
-	/* Load information */
-	uintptr_t load_addr;
-	uintptr_t load_offset;  /* load_addr - recorded vaddr */
-
-	/* Symbol table */
-	ELF(Sym) *symtab;
-	const char *symstrings;
-	ELF(Word) *bucket, *chain;
-	ELF(Word) nbucket, nchain;
-
-	/* Version table */
-	ELF(Versym) *versym;
-	ELF(Verdef) *verdef;
-} vdso_info;
-
-/* Straight from the ELF specification. */
-static unsigned long elf_hash(const unsigned char *name)
-{
-	unsigned long h = 0, g;
-	while (*name)
-	{
-		h = (h << 4) + *name++;
-		if (g = h & 0xf0000000)
-			h ^= g >> 24;
-		h &= ~g;
-	}
-	return h;
-}
-
-void vdso_init_from_sysinfo_ehdr(uintptr_t base)
-{
-	size_t i;
-	bool found_vaddr = false;
-
-	vdso_info.valid = false;
-
-	vdso_info.load_addr = base;
-
-	ELF(Ehdr) *hdr = (ELF(Ehdr)*)base;
-	if (hdr->e_ident[EI_CLASS] !=
-	    (ELF_BITS == 32 ? ELFCLASS32 : ELFCLASS64)) {
-		return;  /* Wrong ELF class -- check ELF_BITS */
-	}
-
-	ELF(Phdr) *pt = (ELF(Phdr)*)(vdso_info.load_addr + hdr->e_phoff);
-	ELF(Dyn) *dyn = 0;
-
-	/*
-	 * We need two things from the segment table: the load offset
-	 * and the dynamic table.
-	 */
-	for (i = 0; i < hdr->e_phnum; i++)
-	{
-		if (pt[i].p_type == PT_LOAD && !found_vaddr) {
-			found_vaddr = true;
-			vdso_info.load_offset =	base
-				+ (uintptr_t)pt[i].p_offset
-				- (uintptr_t)pt[i].p_vaddr;
-		} else if (pt[i].p_type == PT_DYNAMIC) {
-			dyn = (ELF(Dyn)*)(base + pt[i].p_offset);
-		}
-	}
-
-	if (!found_vaddr || !dyn)
-		return;  /* Failed */
-
-	/*
-	 * Fish out the useful bits of the dynamic table.
-	 */
-	ELF(Word) *hash = 0;
-	vdso_info.symstrings = 0;
-	vdso_info.symtab = 0;
-	vdso_info.versym = 0;
-	vdso_info.verdef = 0;
-	for (i = 0; dyn[i].d_tag != DT_NULL; i++) {
-		switch (dyn[i].d_tag) {
-		case DT_STRTAB:
-			vdso_info.symstrings = (const char *)
-				((uintptr_t)dyn[i].d_un.d_ptr
-				 + vdso_info.load_offset);
-			break;
-		case DT_SYMTAB:
-			vdso_info.symtab = (ELF(Sym) *)
-				((uintptr_t)dyn[i].d_un.d_ptr
-				 + vdso_info.load_offset);
-			break;
-		case DT_HASH:
-			hash = (ELF(Word) *)
-				((uintptr_t)dyn[i].d_un.d_ptr
-				 + vdso_info.load_offset);
-			break;
-		case DT_VERSYM:
-			vdso_info.versym = (ELF(Versym) *)
-				((uintptr_t)dyn[i].d_un.d_ptr
-				 + vdso_info.load_offset);
-			break;
-		case DT_VERDEF:
-			vdso_info.verdef = (ELF(Verdef) *)
-				((uintptr_t)dyn[i].d_un.d_ptr
-				 + vdso_info.load_offset);
-			break;
-		}
-	}
-	if (!vdso_info.symstrings || !vdso_info.symtab || !hash)
-		return;  /* Failed */
-
-	if (!vdso_info.verdef)
-		vdso_info.versym = 0;
-
-	/* Parse the hash table header. */
-	vdso_info.nbucket = hash[0];
-	vdso_info.nchain = hash[1];
-	vdso_info.bucket = &hash[2];
-	vdso_info.chain = &hash[vdso_info.nbucket + 2];
-
-	/* That's all we need. */
-	vdso_info.valid = true;
-}
-
-static bool vdso_match_version(ELF(Versym) ver,
-			       const char *name, ELF(Word) hash)
-{
-	/*
-	 * This is a helper function to check if the version indexed by
-	 * ver matches name (which hashes to hash).
-	 *
-	 * The version definition table is a mess, and I don't know how
-	 * to do this in better than linear time without allocating memory
-	 * to build an index.  I also don't know why the table has
-	 * variable size entries in the first place.
-	 *
-	 * For added fun, I can't find a comprehensible specification of how
-	 * to parse all the weird flags in the table.
-	 *
-	 * So I just parse the whole table every time.
-	 */
-
-	/* First step: find the version definition */
-	ver &= 0x7fff;  /* Apparently bit 15 means "hidden" */
-	ELF(Verdef) *def = vdso_info.verdef;
-	while(true) {
-		if ((def->vd_flags & VER_FLG_BASE) == 0
-		    && (def->vd_ndx & 0x7fff) == ver)
-			break;
-
-		if (def->vd_next == 0)
-			return false;  /* No definition. */
-
-		def = (ELF(Verdef) *)((char *)def + def->vd_next);
-	}
-
-	/* Now figure out whether it matches. */
-	ELF(Verdaux) *aux = (ELF(Verdaux)*)((char *)def + def->vd_aux);
-	return def->vd_hash == hash
-		&& !strcmp(name, vdso_info.symstrings + aux->vda_name);
-}
-
-void *vdso_sym(const char *version, const char *name)
-{
-	unsigned long ver_hash;
-	if (!vdso_info.valid)
-		return 0;
-
-	ver_hash = elf_hash(version);
-	ELF(Word) chain = vdso_info.bucket[elf_hash(name) % vdso_info.nbucket];
-
-	for (; chain != STN_UNDEF; chain = vdso_info.chain[chain]) {
-		ELF(Sym) *sym = &vdso_info.symtab[chain];
-
-		/* Check for a defined global or weak function w/ right name. */
-		if (ELF64_ST_TYPE(sym->st_info) != STT_FUNC)
-			continue;
-		if (ELF64_ST_BIND(sym->st_info) != STB_GLOBAL &&
-		    ELF64_ST_BIND(sym->st_info) != STB_WEAK)
-			continue;
-		if (sym->st_shndx == SHN_UNDEF)
-			continue;
-		if (strcmp(name, vdso_info.symstrings + sym->st_name))
-			continue;
-
-		/* Check symbol version. */
-		if (vdso_info.versym
-		    && !vdso_match_version(vdso_info.versym[chain],
-					   version, ver_hash))
-			continue;
-
-		return (void *)(vdso_info.load_offset + sym->st_value);
-	}
-
-	return 0;
-}
-
-void vdso_init_from_auxv(void *auxv)
-{
-	ELF(auxv_t) *elf_auxv = auxv;
-	for (int i = 0; elf_auxv[i].a_type != AT_NULL; i++)
-	{
-		if (elf_auxv[i].a_type == AT_SYSINFO_EHDR) {
-			vdso_init_from_sysinfo_ehdr(elf_auxv[i].a_un.a_val);
-			return;
-		}
-	}
-
-	vdso_info.valid = false;
-}