Index: fusl/src/internal/vdso.c |
diff --git a/fusl/src/internal/vdso.c b/fusl/src/internal/vdso.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..6ae0212e5c1ee7a784fa71dfb80981fa9bc8ffd7 |
--- /dev/null |
+++ b/fusl/src/internal/vdso.c |
@@ -0,0 +1,91 @@ |
+#include <elf.h> |
+#include <limits.h> |
+#include <stdint.h> |
+#include <string.h> |
+#include "libc.h" |
+#include "syscall.h" |
+ |
+#ifdef VDSO_USEFUL |
+ |
+#if ULONG_MAX == 0xffffffff |
+typedef Elf32_Ehdr Ehdr; |
+typedef Elf32_Phdr Phdr; |
+typedef Elf32_Sym Sym; |
+typedef Elf32_Verdef Verdef; |
+typedef Elf32_Verdaux Verdaux; |
+#else |
+typedef Elf64_Ehdr Ehdr; |
+typedef Elf64_Phdr Phdr; |
+typedef Elf64_Sym Sym; |
+typedef Elf64_Verdef Verdef; |
+typedef Elf64_Verdaux Verdaux; |
+#endif |
+ |
+static int checkver(Verdef *def, int vsym, const char *vername, char *strings) |
+{ |
+ vsym &= 0x7fff; |
+ for (;;) { |
+ if (!(def->vd_flags & VER_FLG_BASE) |
+ && (def->vd_ndx & 0x7fff) == vsym) |
+ break; |
+ if (def->vd_next == 0) |
+ return 0; |
+ def = (Verdef *)((char *)def + def->vd_next); |
+ } |
+ Verdaux *aux = (Verdaux *)((char *)def + def->vd_aux); |
+ return !strcmp(vername, strings + aux->vda_name); |
+} |
+ |
+#define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON) |
+#define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE) |
+ |
+void *__vdsosym(const char *vername, const char *name) |
+{ |
+ size_t i; |
+ for (i=0; libc.auxv[i] != AT_SYSINFO_EHDR; i+=2) |
+ if (!libc.auxv[i]) return 0; |
+ Ehdr *eh = (void *)libc.auxv[i+1]; |
+ Phdr *ph = (void *)((char *)eh + eh->e_phoff); |
+ size_t *dynv=0, base=-1; |
+ for (i=0; i<eh->e_phnum; i++, ph=(void *)((char *)ph+eh->e_phentsize)) { |
+ if (ph->p_type == PT_LOAD) |
+ base = (size_t)eh + ph->p_offset - ph->p_vaddr; |
+ else if (ph->p_type == PT_DYNAMIC) |
+ dynv = (void *)((char *)eh + ph->p_offset); |
+ } |
+ if (!dynv || base==(size_t)-1) return 0; |
+ |
+ char *strings = 0; |
+ Sym *syms = 0; |
+ uint32_t *hashtab = 0; |
+ uint16_t *versym = 0; |
+ Verdef *verdef = 0; |
+ |
+ for (i=0; dynv[i]; i+=2) { |
+ void *p = (void *)(base + dynv[i+1]); |
+ switch(dynv[i]) { |
+ case DT_STRTAB: strings = p; break; |
+ case DT_SYMTAB: syms = p; break; |
+ case DT_HASH: hashtab = p; break; |
+ case DT_VERSYM: versym = p; break; |
+ case DT_VERDEF: verdef = p; break; |
+ } |
+ } |
+ |
+ if (!strings || !syms || !hashtab) return 0; |
+ if (!verdef) versym = 0; |
+ |
+ for (i=0; i<hashtab[1]; i++) { |
+ if (!(1<<(syms[i].st_info&0xf) & OK_TYPES)) continue; |
+ if (!(1<<(syms[i].st_info>>4) & OK_BINDS)) continue; |
+ if (!syms[i].st_shndx) continue; |
+ if (strcmp(name, strings+syms[i].st_name)) continue; |
+ if (versym && !checkver(verdef, versym[i], vername, strings)) |
+ continue; |
+ return (void *)(base + syms[i].st_value); |
+ } |
+ |
+ return 0; |
+} |
+ |
+#endif |