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libbacktrace: pass -1 to error callback for unrecognized DWARF
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	PR libbacktrace/98818
	* dwarf.c (dwarf_buf_error): Add errnum parameter.  Change all
	callers.
	* backtrace.h: Update backtrace_error_callback comment.
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@ianlancetaylor
ianlancetaylor committed Mar 2, 2021
1 parent 7854b0b commit 59473f7
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Showing 2 changed files with 43 additions and 30 deletions.
15 changes: 8 additions & 7 deletions backtrace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -54,13 +54,14 @@ struct backtrace_state;
invalid after this function returns.
As a special case, the ERRNUM argument will be passed as -1 if no
debug info can be found for the executable, but the function
requires debug info (e.g., backtrace_full, backtrace_pcinfo). The
MSG in this case will be something along the lines of "no debug
info". Similarly, ERRNUM will be passed as -1 if there is no
symbol table, but the function requires a symbol table (e.g.,
backtrace_syminfo). This may be used as a signal that some other
approach should be tried. */
debug info can be found for the executable, or if the debug info
exists but has an unsupported version, but the function requires
debug info (e.g., backtrace_full, backtrace_pcinfo). The MSG in
this case will be something along the lines of "no debug info".
Similarly, ERRNUM will be passed as -1 if there is no symbol table,
but the function requires a symbol table (e.g., backtrace_syminfo).
This may be used as a signal that some other approach should be
tried. */

typedef void (*backtrace_error_callback) (void *data, const char *msg,
int errnum);
Expand Down
58 changes: 35 additions & 23 deletions dwarf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -743,13 +743,13 @@ struct dwarf_data
/* Report an error for a DWARF buffer. */

static void
dwarf_buf_error (struct dwarf_buf *buf, const char *msg)
dwarf_buf_error (struct dwarf_buf *buf, const char *msg, int errnum)
{
char b[200];

snprintf (b, sizeof b, "%s in %s at %d",
msg, buf->name, (int) (buf->buf - buf->start));
buf->error_callback (buf->data, b, 0);
buf->error_callback (buf->data, b, errnum);
}

/* Require at least COUNT bytes in BUF. Return 1 if all is well, 0 on
Expand All @@ -763,7 +763,7 @@ require (struct dwarf_buf *buf, size_t count)

if (!buf->reported_underflow)
{
dwarf_buf_error (buf, "DWARF underflow");
dwarf_buf_error (buf, "DWARF underflow", 0);
buf->reported_underflow = 1;
}

Expand Down Expand Up @@ -925,7 +925,7 @@ read_address (struct dwarf_buf *buf, int addrsize)
case 8:
return read_uint64 (buf);
default:
dwarf_buf_error (buf, "unrecognized address size");
dwarf_buf_error (buf, "unrecognized address size", 0);
return 0;
}
}
Expand Down Expand Up @@ -976,7 +976,7 @@ read_uleb128 (struct dwarf_buf *buf)
ret |= ((uint64_t) (b & 0x7f)) << shift;
else if (!overflow)
{
dwarf_buf_error (buf, "LEB128 overflows uint64_t");
dwarf_buf_error (buf, "LEB128 overflows uint64_t", 0);
overflow = 1;
}
shift += 7;
Expand Down Expand Up @@ -1011,7 +1011,7 @@ read_sleb128 (struct dwarf_buf *buf)
val |= ((uint64_t) (b & 0x7f)) << shift;
else if (!overflow)
{
dwarf_buf_error (buf, "signed LEB128 overflows uint64_t");
dwarf_buf_error (buf, "signed LEB128 overflows uint64_t", 0);
overflow = 1;
}
shift += 7;
Expand Down Expand Up @@ -1151,7 +1151,7 @@ read_attribute (enum dwarf_form form, uint64_t implicit_val,
offset = read_offset (buf, is_dwarf64);
if (offset >= dwarf_sections->size[DEBUG_STR])
{
dwarf_buf_error (buf, "DW_FORM_strp out of range");
dwarf_buf_error (buf, "DW_FORM_strp out of range", 0);
return 0;
}
val->encoding = ATTR_VAL_STRING;
Expand All @@ -1166,7 +1166,7 @@ read_attribute (enum dwarf_form form, uint64_t implicit_val,
offset = read_offset (buf, is_dwarf64);
if (offset >= dwarf_sections->size[DEBUG_LINE_STR])
{
dwarf_buf_error (buf, "DW_FORM_line_strp out of range");
dwarf_buf_error (buf, "DW_FORM_line_strp out of range", 0);
return 0;
}
val->encoding = ATTR_VAL_STRING;
Expand Down Expand Up @@ -1213,7 +1213,8 @@ read_attribute (enum dwarf_form form, uint64_t implicit_val,
if (form == DW_FORM_implicit_const)
{
dwarf_buf_error (buf,
"DW_FORM_indirect to DW_FORM_implicit_const");
"DW_FORM_indirect to DW_FORM_implicit_const",
0);
return 0;
}
return read_attribute ((enum dwarf_form) form, 0, buf, is_dwarf64,
Expand Down Expand Up @@ -1346,7 +1347,7 @@ read_attribute (enum dwarf_form form, uint64_t implicit_val,
}
if (offset >= altlink->dwarf_sections.size[DEBUG_STR])
{
dwarf_buf_error (buf, "DW_FORM_strp_sup out of range");
dwarf_buf_error (buf, "DW_FORM_strp_sup out of range", 0);
return 0;
}
val->encoding = ATTR_VAL_STRING;
Expand All @@ -1355,7 +1356,7 @@ read_attribute (enum dwarf_form form, uint64_t implicit_val,
return 1;
}
default:
dwarf_buf_error (buf, "unrecognized DWARF form");
dwarf_buf_error (buf, "unrecognized DWARF form", -1);
return 0;
}
}
Expand Down Expand Up @@ -1404,7 +1405,9 @@ resolve_string (const struct dwarf_sections *dwarf_sections, int is_dwarf64,
offset = read_offset (&offset_buf, is_dwarf64);
if (offset >= dwarf_sections->size[DEBUG_STR])
{
dwarf_buf_error (&offset_buf, "DW_FORM_strx offset out of range");
dwarf_buf_error (&offset_buf,
"DW_FORM_strx offset out of range",
0);
return 0;
}
*string = (const char *) dwarf_sections->data[DEBUG_STR] + offset;
Expand Down Expand Up @@ -2212,7 +2215,7 @@ add_ranges_from_rnglists (
break;

default:
dwarf_buf_error (&rnglists_buf, "unrecognized DW_RLE value");
dwarf_buf_error (&rnglists_buf, "unrecognized DW_RLE value", -1);
return 0;
}
}
Expand Down Expand Up @@ -2479,7 +2482,7 @@ build_address_map (struct backtrace_state *state, uintptr_t base_address,
version = read_uint16 (&unit_buf);
if (version < 2 || version > 5)
{
dwarf_buf_error (&unit_buf, "unrecognized DWARF version");
dwarf_buf_error (&unit_buf, "unrecognized DWARF version", -1);
goto fail;
}

Expand Down Expand Up @@ -2758,7 +2761,8 @@ read_v2_paths (struct backtrace_state *state, struct unit *u,
{
dwarf_buf_error (hdr_buf,
("invalid directory index in "
"line number program header"));
"line number program header"),
0);
return 0;
}
dir_len = strlen (dir);
Expand Down Expand Up @@ -2827,7 +2831,8 @@ read_lnct (struct backtrace_state *state, struct dwarf_data *ddata,
{
dwarf_buf_error (hdr_buf,
("invalid directory index in "
"line number program header"));
"line number program header"),
0);
return 0;
}
dir = hdr->dirs[val.u.uint];
Expand All @@ -2842,7 +2847,8 @@ read_lnct (struct backtrace_state *state, struct dwarf_data *ddata,
if (path == NULL)
{
dwarf_buf_error (hdr_buf,
"missing file name in line number program header");
"missing file name in line number program header",
0);
return 0;
}

Expand Down Expand Up @@ -2969,7 +2975,7 @@ read_line_header (struct backtrace_state *state, struct dwarf_data *ddata,
hdr->version = read_uint16 (line_buf);
if (hdr->version < 2 || hdr->version > 5)
{
dwarf_buf_error (line_buf, "unsupported line number version");
dwarf_buf_error (line_buf, "unsupported line number version", -1);
return 0;
}

Expand All @@ -2983,7 +2989,8 @@ read_line_header (struct backtrace_state *state, struct dwarf_data *ddata,
if (read_byte (line_buf) != 0)
{
dwarf_buf_error (line_buf,
"non-zero segment_selector_size not supported");
"non-zero segment_selector_size not supported",
-1);
return 0;
}
}
Expand Down Expand Up @@ -3124,7 +3131,8 @@ read_line_program (struct backtrace_state *state, struct dwarf_data *ddata,
{
dwarf_buf_error (line_buf,
("invalid directory index "
"in line number program"));
"in line number program"),
0);
return 0;
}
dir_len = strlen (dir);
Expand Down Expand Up @@ -3190,7 +3198,8 @@ read_line_program (struct backtrace_state *state, struct dwarf_data *ddata,
{
dwarf_buf_error (line_buf,
("invalid file number in "
"line number program"));
"line number program"),
0);
return 0;
}
filename = hdr->filenames[fileno];
Expand Down Expand Up @@ -3425,7 +3434,9 @@ read_referenced_name (struct dwarf_data *ddata, struct unit *u,
code = read_uleb128 (&unit_buf);
if (code == 0)
{
dwarf_buf_error (&unit_buf, "invalid abstract origin or specification");
dwarf_buf_error (&unit_buf,
"invalid abstract origin or specification",
0);
return NULL;
}

Expand Down Expand Up @@ -3628,7 +3639,8 @@ read_function_entry (struct backtrace_state *state, struct dwarf_data *ddata,
{
dwarf_buf_error (unit_buf,
("invalid file number in "
"DW_AT_call_file attribute"));
"DW_AT_call_file attribute"),
0);
return 0;
}
function->caller_filename =
Expand Down

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