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libbacktrace: support FDPIC (1dd5c40)
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@wolfpld
wolfpld committed Aug 24, 2024
1 parent 0d0e56d commit e26c343
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Showing 4 changed files with 108 additions and 48 deletions.
63 changes: 35 additions & 28 deletions public/libbacktrace/dwarf.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -725,8 +725,8 @@ struct dwarf_data
struct dwarf_data *next;
/* The data for .gnu_debugaltlink. */
struct dwarf_data *altlink;
/* The base address for this file. */
uintptr_t base_address;
/* The base address mapping for this file. */
struct libbacktrace_base_address base_address;
/* A sorted list of address ranges. */
struct unit_addrs *addrs;
/* Number of address ranges in list. */
Expand Down Expand Up @@ -1947,8 +1947,9 @@ update_pcrange (const struct attr* attr, const struct attr_val* val,
static int
add_low_high_range (struct backtrace_state *state,
const struct dwarf_sections *dwarf_sections,
uintptr_t base_address, int is_bigendian,
struct unit *u, const struct pcrange *pcrange,
struct libbacktrace_base_address base_address,
int is_bigendian, struct unit *u,
const struct pcrange *pcrange,
int (*add_range) (struct backtrace_state *state,
void *rdata, uintptr_t lowpc,
uintptr_t highpc,
Expand Down Expand Up @@ -1983,8 +1984,8 @@ add_low_high_range (struct backtrace_state *state,

/* Add in the base address of the module when recording PC values,
so that we can look up the PC directly. */
lowpc += base_address;
highpc += base_address;
lowpc = libbacktrace_add_base (lowpc, base_address);
highpc = libbacktrace_add_base (highpc, base_address);

return add_range (state, rdata, lowpc, highpc, error_callback, data, vec);
}
Expand All @@ -1996,7 +1997,7 @@ static int
add_ranges_from_ranges (
struct backtrace_state *state,
const struct dwarf_sections *dwarf_sections,
uintptr_t base_address, int is_bigendian,
struct libbacktrace_base_address base_address, int is_bigendian,
struct unit *u, uintptr_t base,
const struct pcrange *pcrange,
int (*add_range) (struct backtrace_state *state, void *rdata,
Expand Down Expand Up @@ -2042,10 +2043,11 @@ add_ranges_from_ranges (
base = (uintptr_t) high;
else
{
if (!add_range (state, rdata,
(uintptr_t) low + base + base_address,
(uintptr_t) high + base + base_address,
error_callback, data, vec))
uintptr_t rl, rh;

rl = libbacktrace_add_base ((uintptr_t) low + base, base_address);
rh = libbacktrace_add_base ((uintptr_t) high + base, base_address);
if (!add_range (state, rdata, rl, rh, error_callback, data, vec))
return 0;
}
}
Expand All @@ -2063,7 +2065,7 @@ static int
add_ranges_from_rnglists (
struct backtrace_state *state,
const struct dwarf_sections *dwarf_sections,
uintptr_t base_address, int is_bigendian,
struct libbacktrace_base_address base_address, int is_bigendian,
struct unit *u, uintptr_t base,
const struct pcrange *pcrange,
int (*add_range) (struct backtrace_state *state, void *rdata,
Expand Down Expand Up @@ -2146,9 +2148,10 @@ add_ranges_from_rnglists (
u->addrsize, is_bigendian, index,
error_callback, data, &high))
return 0;
if (!add_range (state, rdata, low + base_address,
high + base_address, error_callback, data,
vec))
if (!add_range (state, rdata,
libbacktrace_add_base (low, base_address),
libbacktrace_add_base (high, base_address),
error_callback, data, vec))
return 0;
}
break;
Expand All @@ -2165,7 +2168,7 @@ add_ranges_from_rnglists (
error_callback, data, &low))
return 0;
length = read_uleb128 (&rnglists_buf);
low += base_address;
low = libbacktrace_add_base (low, base_address);
if (!add_range (state, rdata, low, low + length,
error_callback, data, vec))
return 0;
Expand All @@ -2179,8 +2182,9 @@ add_ranges_from_rnglists (

low = read_uleb128 (&rnglists_buf);
high = read_uleb128 (&rnglists_buf);
if (!add_range (state, rdata, low + base + base_address,
high + base + base_address,
if (!add_range (state, rdata,
libbacktrace_add_base (low + base, base_address),
libbacktrace_add_base (high + base, base_address),
error_callback, data, vec))
return 0;
}
Expand All @@ -2197,9 +2201,10 @@ add_ranges_from_rnglists (

low = (uintptr_t) read_address (&rnglists_buf, u->addrsize);
high = (uintptr_t) read_address (&rnglists_buf, u->addrsize);
if (!add_range (state, rdata, low + base_address,
high + base_address, error_callback, data,
vec))
if (!add_range (state, rdata,
libbacktrace_add_base (low, base_address),
libbacktrace_add_base (high, base_address),
error_callback, data, vec))
return 0;
}
break;
Expand All @@ -2211,7 +2216,7 @@ add_ranges_from_rnglists (

low = (uintptr_t) read_address (&rnglists_buf, u->addrsize);
length = (uintptr_t) read_uleb128 (&rnglists_buf);
low += base_address;
low = libbacktrace_add_base (low, base_address);
if (!add_range (state, rdata, low, low + length,
error_callback, data, vec))
return 0;
Expand Down Expand Up @@ -2239,7 +2244,7 @@ add_ranges_from_rnglists (
static int
add_ranges (struct backtrace_state *state,
const struct dwarf_sections *dwarf_sections,
uintptr_t base_address, int is_bigendian,
struct libbacktrace_base_address base_address, int is_bigendian,
struct unit *u, uintptr_t base, const struct pcrange *pcrange,
int (*add_range) (struct backtrace_state *state, void *rdata,
uintptr_t lowpc, uintptr_t highpc,
Expand Down Expand Up @@ -2275,7 +2280,8 @@ add_ranges (struct backtrace_state *state,
read, 0 if there is some error. */

static int
find_address_ranges (struct backtrace_state *state, uintptr_t base_address,
find_address_ranges (struct backtrace_state *state,
struct libbacktrace_base_address base_address,
struct dwarf_buf *unit_buf,
const struct dwarf_sections *dwarf_sections,
int is_bigendian, struct dwarf_data *altlink,
Expand Down Expand Up @@ -2430,7 +2436,8 @@ find_address_ranges (struct backtrace_state *state, uintptr_t base_address,
on success, 0 on failure. */

static int
build_address_map (struct backtrace_state *state, uintptr_t base_address,
build_address_map (struct backtrace_state *state,
struct libbacktrace_base_address base_address,
const struct dwarf_sections *dwarf_sections,
int is_bigendian, struct dwarf_data *altlink,
backtrace_error_callback error_callback, void *data,
Expand Down Expand Up @@ -2649,7 +2656,7 @@ add_line (struct backtrace_state *state, struct dwarf_data *ddata,

/* Add in the base address here, so that we can look up the PC
directly. */
ln->pc = pc + ddata->base_address;
ln->pc = libbacktrace_add_base (pc, ddata->base_address);

ln->filename = filename;
ln->lineno = lineno;
Expand Down Expand Up @@ -4329,7 +4336,7 @@ dwarf_fileline (struct backtrace_state *state, uintptr_t pc,

static struct dwarf_data *
build_dwarf_data (struct backtrace_state *state,
uintptr_t base_address,
struct libbacktrace_base_address base_address,
const struct dwarf_sections *dwarf_sections,
int is_bigendian,
struct dwarf_data *altlink,
Expand Down Expand Up @@ -4387,7 +4394,7 @@ build_dwarf_data (struct backtrace_state *state,

int
backtrace_dwarf_add (struct backtrace_state *state,
uintptr_t base_address,
struct libbacktrace_base_address base_address,
const struct dwarf_sections *dwarf_sections,
int is_bigendian,
struct dwarf_data *fileline_altlink,
Expand Down
32 changes: 23 additions & 9 deletions public/libbacktrace/elf.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -643,7 +643,7 @@ elf_symbol_search (const void *vkey, const void *ventry)

static int
elf_initialize_syminfo (struct backtrace_state *state,
uintptr_t base_address,
struct libbacktrace_base_address base_address,
const unsigned char *symtab_data, size_t symtab_size,
const unsigned char *strtab, size_t strtab_size,
backtrace_error_callback error_callback,
Expand Down Expand Up @@ -709,7 +709,8 @@ elf_initialize_syminfo (struct backtrace_state *state,
= *(const b_elf_addr *) (opd->data + (sym->st_value - opd->addr));
else
elf_symbols[j].address = sym->st_value;
elf_symbols[j].address += base_address;
elf_symbols[j].address =
libbacktrace_add_base (elf_symbols[j].address, base_address);
elf_symbols[j].size = sym->st_size;
++j;
}
Expand Down Expand Up @@ -6517,7 +6518,8 @@ backtrace_uncompress_lzma (struct backtrace_state *state,
static int
elf_add (struct backtrace_state *state, const char *filename, int descriptor,
const unsigned char *memory, size_t memory_size,
uintptr_t base_address, struct elf_ppc64_opd_data *caller_opd,
struct libbacktrace_base_address base_address,
struct elf_ppc64_opd_data *caller_opd,
backtrace_error_callback error_callback, void *data,
fileline *fileline_fn, int *found_sym, int *found_dwarf,
struct dwarf_data **fileline_entry, int exe, int debuginfo,
Expand Down Expand Up @@ -7419,6 +7421,7 @@ phdr_callback (struct PhdrIterate *info, void *pdata)
const char *filename;
int descriptor;
int does_not_exist;
struct libbacktrace_base_address base_address;
fileline elf_fileline_fn;
int found_dwarf;

Expand Down Expand Up @@ -7448,7 +7451,8 @@ phdr_callback (struct PhdrIterate *info, void *pdata)
return 0;
}

if (elf_add (pd->state, filename, descriptor, NULL, 0, info->dlpi_addr, NULL,
base_address.m = info->dlpi_addr;
if (elf_add (pd->state, filename, descriptor, NULL, 0, base_address, NULL,
pd->error_callback, pd->data, &elf_fileline_fn, pd->found_sym,
&found_dwarf, NULL, 0, 0, NULL, 0))
{
Expand Down Expand Up @@ -7537,11 +7541,21 @@ backtrace_initialize (struct backtrace_state *state, const char *filename,
fileline elf_fileline_fn = elf_nodebug;
struct phdr_data pd;

ret = elf_add (state, filename, descriptor, NULL, 0, 0, NULL, error_callback,
data, &elf_fileline_fn, &found_sym, &found_dwarf, NULL, 1, 0,
NULL, 0);
if (!ret)
return 0;

/* When using fdpic we must use dl_iterate_phdr for all modules, including
the main executable, so that we can get the right base address
mapping. */
if (!libbacktrace_using_fdpic ())
{
struct libbacktrace_base_address zero_base_address;

memset (&zero_base_address, 0, sizeof zero_base_address);
ret = elf_add (state, filename, descriptor, NULL, 0, zero_base_address,
NULL, error_callback, data, &elf_fileline_fn, &found_sym,
&found_dwarf, NULL, 1, 0, NULL, 0);
if (!ret)
return 0;
}

pd.state = state;
pd.error_callback = error_callback;
Expand Down
36 changes: 35 additions & 1 deletion public/libbacktrace/internal.hpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -333,10 +333,44 @@ struct dwarf_sections

struct dwarf_data;

/* The load address mapping. */

#if defined(__FDPIC__) && defined(HAVE_DL_ITERATE_PHDR) && (defined(HAVE_LINK_H) || defined(HAVE_SYS_LINK_H))

#ifdef HAVE_LINK_H
#include <link.h>
#endif
#ifdef HAVE_SYS_LINK_H
#include <sys/link.h>
#endif

#define libbacktrace_using_fdpic() (1)

struct libbacktrace_base_address
{
struct elf32_fdpic_loadaddr m;
};

#define libbacktrace_add_base(pc, base) \
((uintptr_t) (__RELOC_POINTER ((pc), (base).m)))

#else /* not _FDPIC__ */

#define libbacktrace_using_fdpic() (0)

struct libbacktrace_base_address
{
uintptr_t m;
};

#define libbacktrace_add_base(pc, base) ((pc) + (base).m)

#endif /* not _FDPIC__ */

/* Add file/line information for a DWARF module. */

extern int backtrace_dwarf_add (struct backtrace_state *state,
uintptr_t base_address,
struct libbacktrace_base_address base_address,
const struct dwarf_sections *dwarf_sections,
int is_bigendian,
struct dwarf_data *fileline_altlink,
Expand Down
25 changes: 15 additions & 10 deletions public/libbacktrace/macho.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -318,8 +318,9 @@ static const char * const dwarf_section_names[DEBUG_MAX] =
/* Forward declaration. */

static int macho_add (struct backtrace_state *, const char *, int, off_t,
const unsigned char *, uintptr_t, int,
backtrace_error_callback, void *, fileline *, int *);
const unsigned char *, struct libbacktrace_base_address,
int, backtrace_error_callback, void *, fileline *,
int *);

/* A dummy callback function used when we can't find any debug info. */

Expand Down Expand Up @@ -514,7 +515,7 @@ macho_defined_symbol (uint8_t type)

static int
macho_add_symtab (struct backtrace_state *state, int descriptor,
uintptr_t base_address, int is_64,
struct libbacktrace_base_address base_address, int is_64,
off_t symoff, unsigned int nsyms, off_t stroff,
unsigned int strsize,
backtrace_error_callback error_callback, void *data)
Expand Down Expand Up @@ -629,7 +630,7 @@ macho_add_symtab (struct backtrace_state *state, int descriptor,
if (name[0] == '_')
++name;
macho_symbols[j].name = name;
macho_symbols[j].address = value + base_address;
macho_symbols[j].address = libbacktrace_add_base (value, base_address);
++j;
}

Expand Down Expand Up @@ -762,7 +763,8 @@ macho_syminfo (struct backtrace_state *state, uintptr_t addr,
static int
macho_add_fat (struct backtrace_state *state, const char *filename,
int descriptor, int swapped, off_t offset,
const unsigned char *match_uuid, uintptr_t base_address,
const unsigned char *match_uuid,
struct libbacktrace_base_address base_address,
int skip_symtab, uint32_t nfat_arch, int is_64,
backtrace_error_callback error_callback, void *data,
fileline *fileline_fn, int *found_sym)
Expand Down Expand Up @@ -864,7 +866,8 @@ macho_add_fat (struct backtrace_state *state, const char *filename,

static int
macho_add_dsym (struct backtrace_state *state, const char *filename,
uintptr_t base_address, const unsigned char *uuid,
struct libbacktrace_base_address base_address,
const unsigned char *uuid,
backtrace_error_callback error_callback, void *data,
fileline* fileline_fn)
{
Expand Down Expand Up @@ -982,7 +985,7 @@ macho_add_dsym (struct backtrace_state *state, const char *filename,
static int
macho_add (struct backtrace_state *state, const char *filename, int descriptor,
off_t offset, const unsigned char *match_uuid,
uintptr_t base_address, int skip_symtab,
struct libbacktrace_base_address base_address, int skip_symtab,
backtrace_error_callback error_callback, void *data,
fileline *fileline_fn, int *found_sym)
{
Expand Down Expand Up @@ -1244,7 +1247,7 @@ backtrace_initialize (struct backtrace_state *state, const char *filename,
c = _dyld_image_count ();
for (i = 0; i < c; ++i)
{
uintptr_t base_address;
struct libbacktrace_base_address base_address;
const char *name;
int d;
fileline mff;
Expand All @@ -1268,7 +1271,7 @@ backtrace_initialize (struct backtrace_state *state, const char *filename,
continue;
}

base_address = _dyld_get_image_vmaddr_slide (i);
base_address.m = _dyld_get_image_vmaddr_slide (i);

mff = macho_nodebug;
if (!macho_add (state, name, d, 0, NULL, base_address, 0,
Expand Down Expand Up @@ -1323,10 +1326,12 @@ backtrace_initialize (struct backtrace_state *state, const char *filename,
void *data, fileline *fileline_fn)
{
fileline macho_fileline_fn;
struct libbacktrace_base_address zero_base_address;
int found_sym;

macho_fileline_fn = macho_nodebug;
if (!macho_add (state, filename, descriptor, 0, NULL, 0, 0,
memset (&zero_base_address, 0, sizeof zero_base_address);
if (!macho_add (state, filename, descriptor, 0, NULL, zero_base_address, 0,
error_callback, data, &macho_fileline_fn, &found_sym))
return 0;

Expand Down

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