1 /* Copyright (C) 2001, 2002, 2007 Free Software Foundation, Inc.
2 Contributed by Jakub Jelinek <jakub@redhat.com>.
4 This file is part of the GNU C Library.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
21 /* Locate the FDE entry for a given address, using PT_GNU_EH_FRAME ELF
22 segment and dl_iterate_phdr to avoid register/deregister calls at
26 # include <shlib-compat.h>
29 #if !defined _LIBC || SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2_5)
34 #define _Unwind_Find_FDE _Unwind_Find_registered_FDE
36 #include <unwind-dw2-fde.c>
38 #undef _Unwind_Find_FDE
40 extern fde * _Unwind_Find_registered_FDE (void *pc,
41 struct dwarf_eh_bases *bases);
42 extern fde * _Unwind_Find_FDE (void *, struct dwarf_eh_bases *);
44 struct unw_eh_callback_data
53 struct unw_eh_frame_hdr
55 unsigned char version;
56 unsigned char eh_frame_ptr_enc;
57 unsigned char fde_count_enc;
58 unsigned char table_enc;
61 /* Like base_of_encoded_value, but take the base from a struct object
62 instead of an _Unwind_Context. */
65 base_from_cb_data (unsigned char encoding, struct unw_eh_callback_data *data)
67 if (encoding == DW_EH_PE_omit)
70 switch (encoding & 0x70)
74 case DW_EH_PE_aligned:
77 case DW_EH_PE_textrel:
78 return (_Unwind_Ptr) data->tbase;
79 case DW_EH_PE_datarel:
80 return (_Unwind_Ptr) data->dbase;
86 _Unwind_IteratePhdrCallback (struct dl_phdr_info *info, size_t size, void *ptr)
88 struct unw_eh_callback_data *data = (struct unw_eh_callback_data *) ptr;
89 const ElfW(Phdr) *phdr, *p_eh_frame_hdr, *p_dynamic;
91 _Unwind_Ptr load_base;
92 const unsigned char *p;
93 const struct unw_eh_frame_hdr *hdr;
97 /* Make sure struct dl_phdr_info is at least as big as we need. */
98 if (size < offsetof (struct dl_phdr_info, dlpi_phnum)
99 + sizeof (info->dlpi_phnum))
103 phdr = info->dlpi_phdr;
104 load_base = info->dlpi_addr;
105 p_eh_frame_hdr = NULL;
108 /* See if PC falls into one of the loaded segments. Find the eh_frame
109 segment at the same time. */
110 for (n = info->dlpi_phnum; --n >= 0; phdr++)
112 if (phdr->p_type == PT_LOAD)
114 _Unwind_Ptr vaddr = phdr->p_vaddr + load_base;
115 if (data->pc >= vaddr && data->pc < vaddr + phdr->p_memsz)
118 else if (phdr->p_type == PT_GNU_EH_FRAME)
119 p_eh_frame_hdr = phdr;
120 else if (phdr->p_type == PT_DYNAMIC)
123 if (!match || !p_eh_frame_hdr)
126 /* Read .eh_frame_hdr header. */
127 hdr = (const struct unw_eh_frame_hdr *)
128 (p_eh_frame_hdr->p_vaddr + load_base);
129 if (hdr->version != 1)
132 #ifdef CRT_GET_RFIB_DATA
137 /* For dynamicly linked executables and shared libraries,
138 DT_PLTGOT is the gp value for that object. */
139 ElfW(Dyn) *dyn = (ElfW(Dyn) *)(p_dynamic->p_vaddr + load_base);
140 for (; dyn->d_tag != DT_NULL ; dyn++)
141 if (dyn->d_tag == DT_PLTGOT)
143 /* On IA-32, _DYNAMIC is writable and GLIBC has relocated it. */
144 data->dbase = (void *) dyn->d_un.d_ptr;
149 # error What is DW_EH_PE_datarel base on this platform?
152 #ifdef CRT_GET_RFIB_TEXT
153 # error What is DW_EH_PE_textrel base on this platform?
156 p = read_encoded_value_with_base (hdr->eh_frame_ptr_enc,
157 base_from_cb_data (hdr->eh_frame_ptr_enc,
159 (const unsigned char *) (hdr + 1),
162 /* We require here specific table encoding to speed things up.
163 Also, DW_EH_PE_datarel here means using PT_GNU_EH_FRAME start
164 as base, not the processor specific DW_EH_PE_datarel. */
165 if (hdr->fde_count_enc != DW_EH_PE_omit
166 && hdr->table_enc == (DW_EH_PE_datarel | DW_EH_PE_sdata4))
168 _Unwind_Ptr fde_count;
170 p = read_encoded_value_with_base (hdr->fde_count_enc,
171 base_from_cb_data (hdr->fde_count_enc,
174 /* Shouldn't happen. */
177 if ((((_Unwind_Ptr) p) & 3) == 0)
180 signed initial_loc __attribute__ ((mode (SI)));
181 signed fde __attribute__ ((mode (SI)));
183 const struct fde_table *table = (const struct fde_table *) p;
185 _Unwind_Ptr data_base = (_Unwind_Ptr) hdr;
187 unsigned int f_enc, f_enc_size;
191 if (data->pc < table[0].initial_loc + data_base)
193 else if (data->pc < table[mid].initial_loc + data_base)
201 if (data->pc < table[mid].initial_loc + data_base)
203 else if (data->pc >= table[mid + 1].initial_loc + data_base)
213 f = (fde *) (table[mid].fde + data_base);
214 f_enc = get_fde_encoding (f);
215 f_enc_size = size_of_encoded_value (f_enc);
216 read_encoded_value_with_base (f_enc & 0x0f, 0,
217 &f->pc_begin[f_enc_size], &range);
218 if (data->pc < table[mid].initial_loc + data_base + range)
220 data->func = (void *) (table[mid].initial_loc + data_base);
225 /* We have no sorted search table, so need to go the slow way.
226 As soon as GLIBC will provide API so to notify that a library has been
227 removed, we could cache this (and thus use search_object). */
229 ob.tbase = data->tbase;
230 ob.dbase = data->dbase;
231 ob.u.single = (fde *) eh_frame;
233 ob.s.b.mixed_encoding = 1; /* Need to assume worst case. */
234 data->ret = linear_search_fdes (&ob, (fde *) eh_frame, (void *) data->pc);
235 if (data->ret != NULL)
237 unsigned int encoding = get_fde_encoding (data->ret);
239 read_encoded_value_with_base (encoding,
240 base_from_cb_data (encoding, data),
241 data->ret->pc_begin, &func);
242 data->func = (void *) func;
248 # define dl_iterate_phdr __dl_iterate_phdr
252 _Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
254 struct unw_eh_callback_data data;
257 ret = _Unwind_Find_registered_FDE (pc, bases);
261 data.pc = (_Unwind_Ptr) pc;
267 if (dl_iterate_phdr (_Unwind_IteratePhdrCallback, &data) < 0)
272 bases->tbase = data.tbase;
273 bases->dbase = data.dbase;
274 bases->func = data.func;