Handle DW_FORM_GNU_strp_alt and DW_FORM_GNU_ref_alt references robustly in
presence of missing .gnu_debugaltlink file.
2018-11-11 Tom de Vries <tdevr...@suse.de>
* dwarf.c (enum attr_val_encoding): Add ATTR_VAL_NONE.
(read_attribute): Add altlink parameter. Handle missing altlink for
DW_FORM_GNU_strp_alt and DW_FORM_GNU_ref_alt.
(find_address_ranges, build_address_map, build_dwarf_data): Add and
handle altlink parameter.
(read_referenced_name, read_function_entry): Add argument to
read_attribute call.
---
libbacktrace/dwarf.c | 39 +++++++++++++++++++++++++++------------
1 file changed, 27 insertions(+), 12 deletions(-)
diff --git a/libbacktrace/dwarf.c b/libbacktrace/dwarf.c
index b571c9fbb06..8b802a085ca 100644
--- a/libbacktrace/dwarf.c
+++ b/libbacktrace/dwarf.c
@@ -129,6 +129,8 @@ struct abbrevs
enum attr_val_encoding
{
+ /* No attribute value. */
+ ATTR_VAL_NONE,
/* An address. */
ATTR_VAL_ADDRESS,
/* A unsigned integer. */
@@ -700,7 +702,7 @@ static int
read_attribute (enum dwarf_form form, struct dwarf_buf *buf,
int is_dwarf64, int version, int addrsize,
const unsigned char *dwarf_str, size_t dwarf_str_size,
- struct attr_val *val)
+ struct attr_val *val, struct dwarf_data *altlink)
{
/* Avoid warnings about val.u.FIELD may be used uninitialized if
this function is inlined. The warnings aren't valid but can
@@ -806,7 +808,7 @@ read_attribute (enum dwarf_form form, struct dwarf_buf *buf,
form = read_uleb128 (buf);
return read_attribute ((enum dwarf_form) form, buf, is_dwarf64,
version, addrsize, dwarf_str, dwarf_str_size,
- val);
+ val, altlink);
}
case DW_FORM_sec_offset:
val->encoding = ATTR_VAL_REF_SECTION;
@@ -832,12 +834,22 @@ read_attribute (enum dwarf_form form, struct dwarf_buf
*buf,
val->u.uint = read_uleb128 (buf);
return 1;
case DW_FORM_GNU_ref_alt:
- val->encoding = ATTR_VAL_REF_SECTION;
val->u.uint = read_offset (buf, is_dwarf64);
+ if (altlink == NULL)
+ {
+ val->encoding = ATTR_VAL_NONE;
+ return 1;
+ }
+ val->encoding = ATTR_VAL_REF_SECTION;
return 1;
case DW_FORM_GNU_strp_alt:
- val->encoding = ATTR_VAL_REF_SECTION;
val->u.uint = read_offset (buf, is_dwarf64);
+ if (altlink == NULL)
+ {
+ val->encoding = ATTR_VAL_NONE;
+ return 1;
+ }
+ val->encoding = ATTR_VAL_REF_SECTION;
return 1;
default:
dwarf_buf_error (buf, "unrecognized DWARF form");
@@ -1277,7 +1289,8 @@ find_address_ranges (struct backtrace_state *state,
uintptr_t base_address,
size_t dwarf_ranges_size,
int is_bigendian, backtrace_error_callback error_callback,
void *data, struct unit *u,
- struct unit_addrs_vector *addrs)
+ struct unit_addrs_vector *addrs,
+ struct dwarf_data *altlink)
{
while (unit_buf->left > 0)
{
@@ -1313,7 +1326,7 @@ find_address_ranges (struct backtrace_state *state,
uintptr_t base_address,
if (!read_attribute (abbrev->attrs[i].form, unit_buf,
u->is_dwarf64, u->version, u->addrsize,
- dwarf_str, dwarf_str_size, &val))
+ dwarf_str, dwarf_str_size, &val, altlink))
return 0;
switch (abbrev->attrs[i].name)
@@ -1412,7 +1425,7 @@ find_address_ranges (struct backtrace_state *state,
uintptr_t base_address,
dwarf_str, dwarf_str_size,
dwarf_ranges, dwarf_ranges_size,
is_bigendian, error_callback, data,
- u, addrs))
+ u, addrs, altlink))
return 0;
}
}
@@ -1431,7 +1444,8 @@ build_address_map (struct backtrace_state *state,
uintptr_t base_address,
const unsigned char *dwarf_ranges, size_t dwarf_ranges_size,
const unsigned char *dwarf_str, size_t dwarf_str_size,
int is_bigendian, backtrace_error_callback error_callback,
- void *data, struct unit_addrs_vector *addrs)
+ void *data, struct unit_addrs_vector *addrs,
+ struct dwarf_data *altlink)
{
struct dwarf_buf info;
struct backtrace_vector units;
@@ -1533,7 +1547,7 @@ build_address_map (struct backtrace_state *state,
uintptr_t base_address,
dwarf_str, dwarf_str_size,
dwarf_ranges, dwarf_ranges_size,
is_bigendian, error_callback, data,
- u, addrs))
+ u, addrs, altlink))
goto fail;
if (unit_buf.reported_underflow)
@@ -2146,7 +2160,7 @@ read_referenced_name (struct dwarf_data *ddata, struct
unit *u,
if (!read_attribute (abbrev->attrs[i].form, &unit_buf,
u->is_dwarf64, u->version, u->addrsize,
ddata->dwarf_str, ddata->dwarf_str_size,
- &val))
+ &val, ddata->altlink))
return NULL;
switch (abbrev->attrs[i].name)
@@ -2359,7 +2373,7 @@ read_function_entry (struct backtrace_state *state,
struct dwarf_data *ddata,
if (!read_attribute (abbrev->attrs[i].form, unit_buf,
u->is_dwarf64, u->version, u->addrsize,
ddata->dwarf_str, ddata->dwarf_str_size,
- &val))
+ &val, ddata->altlink))
return 0;
/* The compile unit sets the base address for any address
@@ -2980,7 +2994,8 @@ build_dwarf_data (struct backtrace_state *state,
if (!build_address_map (state, base_address, dwarf_info, dwarf_info_size,
dwarf_abbrev, dwarf_abbrev_size, dwarf_ranges,
dwarf_ranges_size, dwarf_str, dwarf_str_size,
- is_bigendian, error_callback, data, &addrs_vec))
+ is_bigendian, error_callback, data, &addrs_vec,
+ altlink))
return NULL;
if (!backtrace_vector_release (state, &addrs_vec.vec, error_callback, data))
--
2.16.4
