ldso/include/ldsodefs.h

   1 #ifndef _LDSODEFS_H
   2 #define _LDSODEFS_H     1
   3
   4 #include <bits/kernel-features.h>
   5
   6 #include <features.h>
   7 #include <tls.h>
   8
   9 #ifdef __mips__
  10 /* The MIPS ABI specifies that the dynamic section has to be read-only.  */
  11
  12 #define DL_RO_DYN_SECTION 1
  13
  14 /* TODO: Import in 64-bit relocations from glibc. */
  15 #endif
  16
  17 #ifndef SHARED
  18 # define EXTERN extern
  19 #else
  20 # ifdef IS_IN_rtld
  21 #  define EXTERN
  22 # else
  23 #  define EXTERN extern
  24 # endif
  25 #endif
  26
  27 /* Non-shared code has no support for multiple namespaces.  */
  28 #ifdef SHARED
  29 # define DL_NNS 16
  30 #else
  31 # define DL_NNS 1
  32 #endif
  33
  34 #define GL(x) _##x
  35 #define GLRO(x) _##x
  36
  37 /* Variable pointing to the end of the stack (or close to it).  This value
  38    must be constant over the runtime of the application.  Some programs
  39    might use the variable which results in copy relocations on some
  40    platforms.  But this does not matter, ld.so can always use the local
  41    copy.  */
  42 extern void *__libc_stack_end;
  43
  44 /* Determine next available module ID.  */
  45 extern size_t _dl_next_tls_modid (void) internal_function attribute_hidden;
  46
  47 /* Calculate offset of the TLS blocks in the static TLS block.  */
  48 extern void _dl_determine_tlsoffset (void) internal_function attribute_hidden;
  49
  50 /* Set up the data structures for TLS, when they were not set up at startup.
  51    Returns nonzero on malloc failure.
  52    This is called from _dl_map_object_from_fd or by libpthread.  */
  53 extern int _dl_tls_setup (void) internal_function;
  54 rtld_hidden_proto (_dl_tls_setup)
  55
  56 /* Allocate memory for static TLS block (unless MEM is nonzero) and dtv.  */
  57 extern void *_dl_allocate_tls (void *mem) internal_function;
  58
  59 /* Get size and alignment requirements of the static TLS block.  */
  60 extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp)
  61      internal_function;
  62
  63 extern void _dl_allocate_static_tls (struct link_map *map)
  64      internal_function attribute_hidden;
  65 extern int _dl_try_allocate_static_tls (struct link_map* map)
  66      internal_function attribute_hidden;
  67
  68 /* Taken from glibc/elf/dl-reloc.c */
  69 #define CHECK_STATIC_TLS(sym_map)                                                                                       \
  70         do {                                                                                                                                    \
  71                 if (__builtin_expect ((sym_map)->l_tls_offset == NO_TLS_OFFSET, 0))     \
  72                         _dl_allocate_static_tls (sym_map);                                                              \
  73         } while (0)
  74 #define TRY_STATIC_TLS(sym_map)                                                                                         \
  75         (__builtin_expect ((sym_map)->l_tls_offset != NO_TLS_OFFSET, 1)                 \
  76                  || _dl_try_allocate_static_tls (sym_map) == 0)
  77
  78 /* These are internal entry points to the two halves of _dl_allocate_tls,
  79    only used within rtld.c itself at startup time.  */
  80 extern void *_dl_allocate_tls_storage (void)
  81      internal_function attribute_hidden;
  82 extern void *_dl_allocate_tls_init (void *) internal_function;
  83
  84 /* Deallocate memory allocated with _dl_allocate_tls.  */
  85 extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb) internal_function;
  86
  87 extern void _dl_nothread_init_static_tls (struct link_map *) attribute_hidden;
  88
  89 /* Highest dtv index currently needed.  */
  90 EXTERN size_t _dl_tls_max_dtv_idx;
  91 /* Flag signalling whether there are gaps in the module ID allocation.  */
  92 EXTERN bool _dl_tls_dtv_gaps;
  93 /* Information about the dtv slots.  */
  94 EXTERN struct dtv_slotinfo_list
  95 {
  96   size_t len;
  97   struct dtv_slotinfo_list *next;
  98   struct dtv_slotinfo
  99   {
 100     size_t gen;
 101     bool is_static;
 102     struct link_map *map;
 103   } slotinfo[0];
 104 } *_dl_tls_dtv_slotinfo_list;
 105 /* Number of modules in the static TLS block.  */
 106 EXTERN size_t _dl_tls_static_nelem;
 107 /* Size of the static TLS block.  */
 108 EXTERN size_t _dl_tls_static_size;
 109 /* Size actually allocated in the static TLS block.  */
 110 EXTERN size_t _dl_tls_static_used;
 111 /* Alignment requirement of the static TLS block.  */
 112 EXTERN size_t _dl_tls_static_align;
 113 /* Function pointer for catching TLS errors.  */
 114 #if 1 /* def _LIBC_REENTRANT */
 115 EXTERN void **(*_dl_error_catch_tsd) (void) __attribute__ ((const));
 116 #endif
 117
 118 /* Number of additional entries in the slotinfo array of each slotinfo
 119    list element.  A large number makes it almost certain take we never
 120    have to iterate beyond the first element in the slotinfo list.  */
 121 # define TLS_SLOTINFO_SURPLUS (62)
 122
 123 /* Number of additional slots in the dtv allocated.  */
 124 # define DTV_SURPLUS    (14)
 125
 126 /* Initial dtv of the main thread, not allocated with normal malloc.  */
 127 EXTERN void *_dl_initial_dtv;
 128 /* Generation counter for the dtv.  */
 129 EXTERN size_t _dl_tls_generation;
 130
 131 EXTERN void (*_dl_init_static_tls) (struct link_map *);
 132
 133 /* We have the auxiliary vector.  */
 134 #define HAVE_AUX_VECTOR
 135
 136 /* We can assume that the kernel always provides the AT_UID, AT_EUID,
 137    AT_GID, and AT_EGID values in the auxiliary vector from 2.4.0 or so on.  */
 138 #if __ASSUME_AT_XID
 139 # define HAVE_AUX_XID
 140 #endif
 141
 142 /* We can assume that the kernel always provides the AT_SECURE value
 143    in the auxiliary vector from 2.5.74 or so on.  */
 144 #if __ASSUME_AT_SECURE
 145 # define HAVE_AUX_SECURE
 146 #endif
 147
 148 /* Starting with one of the 2.4.0 pre-releases the Linux kernel passes
 149    up the page size information.  */
 150 #if __ASSUME_AT_PAGESIZE
 151 # define HAVE_AUX_PAGESIZE
 152 #endif
 153
 154 #endif