diff options
Diffstat (limited to 'libbacktrace/elf.c')
| -rw-r--r-- | libbacktrace/elf.c | 1629 |
1 files changed, 1624 insertions, 5 deletions
diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c index fac46860a54..bfedca9a9cb 100644 --- a/libbacktrace/elf.c +++ b/libbacktrace/elf.c @@ -56,6 +56,13 @@ POSSIBILITY OF SUCH DAMAGE. */ #define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK) #endif +#ifndef __GNUC__ +#define __builtin_prefetch(p, r, l) +#define unlikely(x) (x) +#else +#define unlikely(x) __builtin_expect(!!(x), 0) +#endif + #if !defined(HAVE_DECL_STRNLEN) || !HAVE_DECL_STRNLEN /* If strnlen is not declared, provide our own version. */ @@ -164,9 +171,11 @@ dl_iterate_phdr (int (*callback) (struct dl_phdr_info *, #undef SHT_SYMTAB #undef SHT_STRTAB #undef SHT_DYNSYM +#undef SHF_COMPRESSED #undef STT_OBJECT #undef STT_FUNC #undef NT_GNU_BUILD_ID +#undef ELFCOMPRESS_ZLIB /* Basic types. */ @@ -257,6 +266,8 @@ typedef struct { #define SHT_STRTAB 3 #define SHT_DYNSYM 11 +#define SHF_COMPRESSED 0x800 + #if BACKTRACE_ELF_SIZE == 32 typedef struct @@ -296,6 +307,29 @@ typedef struct #define NT_GNU_BUILD_ID 3 +#if BACKTRACE_ELF_SIZE == 32 + +typedef struct +{ + b_elf_word ch_type; /* Compresstion algorithm */ + b_elf_word ch_size; /* Uncompressed size */ + b_elf_word ch_addralign; /* Alignment for uncompressed data */ +} b_elf_chdr; /* Elf_Chdr */ + +#else /* BACKTRACE_ELF_SIZE != 32 */ + +typedef struct +{ + b_elf_word ch_type; /* Compression algorithm */ + b_elf_word ch_reserved; /* Reserved */ + b_elf_xword ch_size; /* Uncompressed size */ + b_elf_xword ch_addralign; /* Alignment for uncompressed data */ +} b_elf_chdr; /* Elf_Chdr */ + +#endif /* BACKTRACE_ELF_SIZE != 32 */ + +#define ELFCOMPRESS_ZLIB 1 + /* An index of ELF sections we care about. */ enum debug_section @@ -305,6 +339,15 @@ enum debug_section DEBUG_ABBREV, DEBUG_RANGES, DEBUG_STR, + + /* The old style compressed sections. This list must correspond to + the list of normal debug sections. */ + ZDEBUG_INFO, + ZDEBUG_LINE, + ZDEBUG_ABBREV, + ZDEBUG_RANGES, + ZDEBUG_STR, + DEBUG_MAX }; @@ -316,7 +359,12 @@ static const char * const debug_section_names[DEBUG_MAX] = ".debug_line", ".debug_abbrev", ".debug_ranges", - ".debug_str" + ".debug_str", + ".zdebug_info", + ".zdebug_line", + ".zdebug_abbrev", + ".zdebug_ranges", + ".zdebug_str" }; /* Information we gather for the sections we care about. */ @@ -329,6 +377,8 @@ struct debug_section_info size_t size; /* Section contents, after read from file. */ const unsigned char *data; + /* Whether the SHF_COMPRESSED flag is set for the section. */ + int compressed; }; /* Information we keep for an ELF symbol. */ @@ -965,6 +1015,1493 @@ elf_open_debugfile_by_debuglink (struct backtrace_state *state, return ddescriptor; } +/* A function useful for setting a breakpoint for an inflation failure + when this code is compiled with -g. */ + +static void +elf_zlib_failed(void) +{ +} + +/* *PVAL is the current value being read from the stream, and *PBITS + is the number of valid bits. Ensure that *PVAL holds at least 15 + bits by reading additional bits from *PPIN, up to PINEND, as + needed. Updates *PPIN, *PVAL and *PBITS. Returns 1 on success, 0 + on error. */ + +static int +elf_zlib_fetch (const unsigned char **ppin, const unsigned char *pinend, + uint32_t *pval, unsigned int *pbits) +{ + unsigned int bits; + const unsigned char *pin; + uint32_t val; + + bits = *pbits; + if (bits >= 15) + return 1; + pin = *ppin; + val = *pval; + + if (unlikely (pinend - pin < 2)) + { + elf_zlib_failed (); + return 0; + } + val |= pin[0] << bits; + val |= pin[1] << (bits + 8); + bits += 16; + pin += 2; + + /* We will need the next two bytes soon. We ask for high temporal + locality because we will need the whole cache line soon. */ + __builtin_prefetch (pin, 0, 3); + __builtin_prefetch (pin + 1, 0, 3); + + *ppin = pin; + *pval = val; + *pbits = bits; + return 1; +} + +/* Huffman code tables, like the rest of the zlib format, are defined + by RFC 1951. We store a Huffman code table as a series of tables + stored sequentially in memory. Each entry in a table is 16 bits. + The first, main, table has 256 entries. It is followed by a set of + secondary tables of length 2 to 128 entries. The maximum length of + a code sequence in the deflate format is 15 bits, so that is all we + need. Each secondary table has an index, which is the offset of + the table in the overall memory storage. + + The deflate format says that all codes of a given bit length are + lexicographically consecutive. Perhaps we could have 130 values + that require a 15-bit code, perhaps requiring three secondary + tables of size 128. I don't know if this is actually possible, but + it suggests that the maximum size required for secondary tables is + 3 * 128 + 3 * 64 ... == 768. The zlib enough program reports 660 + as the maximum. We permit 768, since in addition to the 256 for + the primary table, with two bytes per entry, and with the two + tables we need, that gives us a page. + + A single table entry needs to store a value or (for the main table + only) the index and size of a secondary table. Values range from 0 + to 285, inclusive. Secondary table indexes, per above, range from + 0 to 510. For a value we need to store the number of bits we need + to determine that value (one value may appear multiple times in the + table), which is 1 to 8. For a secondary table we need to store + the number of bits used to index into the table, which is 1 to 7. + And of course we need 1 bit to decide whether we have a value or a + secondary table index. So each entry needs 9 bits for value/table + index, 3 bits for size, 1 bit what it is. For simplicity we use 16 + bits per entry. */ + +/* Number of entries we allocate to for one code table. We get a page + for the two code tables we need. */ + +#define HUFFMAN_TABLE_SIZE (1024) + +/* Bit masks and shifts for the values in the table. */ + +#define HUFFMAN_VALUE_MASK 0x01ff +#define HUFFMAN_BITS_SHIFT 9 +#define HUFFMAN_BITS_MASK 0x7 +#define HUFFMAN_SECONDARY_SHIFT 12 + +/* For working memory while inflating we need two code tables, we need + an array of code lengths (max value 15, so we use unsigned char), + and an array of unsigned shorts used while building a table. The + latter two arrays must be large enough to hold the maximum number + of code lengths, which RFC 1951 defines as 286 + 30. */ + +#define ZDEBUG_TABLE_SIZE \ + (2 * HUFFMAN_TABLE_SIZE * sizeof (uint16_t) \ + + (286 + 30) * sizeof (uint16_t) \ + + (286 + 30) * sizeof (unsigned char)) + +#define ZDEBUG_TABLE_CODELEN_OFFSET \ + (2 * HUFFMAN_TABLE_SIZE * sizeof (uint16_t) \ + + (286 + 30) * sizeof (uint16_t)) + +#define ZDEBUG_TABLE_WORK_OFFSET \ + (2 * HUFFMAN_TABLE_SIZE * sizeof (uint16_t)) + +#ifdef BACKTRACE_GENERATE_FIXED_HUFFMAN_TABLE + +/* Used by the main function that generates the fixed table to learn + the table size. */ +static size_t final_next_secondary; + +#endif + +/* Build a Huffman code table from an array of lengths in CODES of + length CODES_LEN. The table is stored into *TABLE. ZDEBUG_TABLE + is the same as for elf_zlib_inflate, used to find some work space. + Returns 1 on success, 0 on error. */ + +static int +elf_zlib_inflate_table (unsigned char *codes, size_t codes_len, + uint16_t *zdebug_table, uint16_t *table) +{ + uint16_t count[16]; + uint16_t start[16]; + uint16_t prev[16]; + uint16_t firstcode[7]; + uint16_t *next; + size_t i; + size_t j; + unsigned int code; + size_t next_secondary; + + /* Count the number of code of each length. Set NEXT[val] to be the + next value after VAL with the same bit length. */ + + next = (uint16_t *) (((unsigned char *) zdebug_table) + + ZDEBUG_TABLE_WORK_OFFSET); + + memset (&count[0], 0, 16 * sizeof (uint16_t)); + for (i = 0; i < codes_len; ++i) + { + if (unlikely (codes[i] >= 16)) + { + elf_zlib_failed (); + return 0; + } + + if (count[codes[i]] == 0) + { + start[codes[i]] = i; + prev[codes[i]] = i; + } + else + { + next[prev[codes[i]]] = i; + prev[codes[i]] = i; + } + + ++count[codes[i]]; + } + + /* For each length, fill in the table for the codes of that + length. */ + + memset (table, 0, HUFFMAN_TABLE_SIZE * sizeof (uint16_t)); + + /* Handle the values that do not require a secondary table. */ + + code = 0; + for (j = 1; j <= 8; ++j) + { + unsigned int jcnt; + unsigned int val; + + jcnt = count[j]; + if (jcnt == 0) + continue; + + if (unlikely (jcnt > (1U << j))) + { + elf_zlib_failed (); + return 0; + } + + /* There are JCNT values that have this length, the values + starting from START[j] continuing through NEXT[VAL]. Those + values are assigned consecutive values starting at CODE. */ + + val = start[j]; + for (i = 0; i < jcnt; ++i) + { + uint16_t tval; + size_t ind; + unsigned int incr; + + /* In the compressed bit stream, the value VAL is encoded as + J bits with the value C. */ + + if (unlikely ((val & ~HUFFMAN_VALUE_MASK) != 0)) + { + elf_zlib_failed (); + return 0; + } + + tval = val | ((j - 1) << HUFFMAN_BITS_SHIFT); + + /* The table lookup uses 8 bits. If J is less than 8, we + don't know what the other bits will be. We need to fill + in all possibilities in the table. Since the Huffman + code is unambiguous, those entries can't be used for any + other code. */ + + for (ind = code; ind < 0x100; ind += 1 << j) + { + if (unlikely (table[ind] != 0)) + { + elf_zlib_failed (); + return 0; + } + table[ind] = tval; + } + + /* Advance to the next value with this length. */ + if (i + 1 < jcnt) + val = next[val]; + + /* The Huffman codes are stored in the bitstream with the + most significant bit first, as is required to make them + unambiguous. The effect is that when we read them from + the bitstream we see the bit sequence in reverse order: + the most significant bit of the Huffman code is the least + significant bit of the value we read from the bitstream. + That means that to make our table lookups work, we need + to reverse the bits of CODE. Since reversing bits is + tedious and in general requires using a table, we instead + increment CODE in reverse order. That is, if the number + of bits we are currently using, here named J, is 3, we + count as 000, 100, 010, 110, 001, 101, 011, 111, which is + to say the numbers from 0 to 7 but with the bits + reversed. Going to more bits, aka incrementing J, + effectively just adds more zero bits as the beginning, + and as such does not change the numeric value of CODE. + + To increment CODE of length J in reverse order, find the + most significant zero bit and set it to one while + clearing all higher bits. In other words, add 1 modulo + 2^J, only reversed. */ + + incr = 1U << (j - 1); + while ((code & incr) != 0) + incr >>= 1; + if (incr == 0) + code = 0; + else + { + code &= incr - 1; + code += incr; + } + } + } + + /* Handle the values that require a secondary table. */ + + /* Set FIRSTCODE, the number at which the codes start, for each + length. */ + + for (j = 9; j < 16; j++) + { + unsigned int jcnt; + unsigned int k; + + jcnt = count[j]; + if (jcnt == 0) + continue; + + /* There are JCNT values that have this length, the values + starting from START[j]. Those values are assigned + consecutive values starting at CODE. */ + + firstcode[j - 9] = code; + + /* Reverse add JCNT to CODE modulo 2^J. */ + for (k = 0; k < j; ++k) + { + if ((jcnt & (1U << k)) != 0) + { + unsigned int m; + unsigned int bit; + + bit = 1U << (j - k - 1); + for (m = 0; m < j - k; ++m, bit >>= 1) + { + if ((code & bit) == 0) + { + code += bit; + break; + } + code &= ~bit; + } + jcnt &= ~(1U << k); + } + } + if (unlikely (jcnt != 0)) + { + elf_zlib_failed (); + return 0; + } + } + + /* For J from 9 to 15, inclusive, we store COUNT[J] consecutive + values starting at START[J] with consecutive codes starting at + FIRSTCODE[J - 9]. In the primary table we need to point to the + secondary table, and the secondary table will be indexed by J - 9 + bits. We count down from 15 so that we install the larger + secondary tables first, as the smaller ones may be embedded in + the larger ones. */ + + next_secondary = 0; /* Index of next secondary table (after primary). */ + for (j = 15; j >= 9; j--) + { + unsigned int jcnt; + unsigned int val; + size_t primary; /* Current primary index. */ + size_t secondary; /* Offset to current secondary table. */ + size_t secondary_bits; /* Bit size of current secondary table. */ + + jcnt = count[j]; + if (jcnt == 0) + continue; + + val = start[j]; + code = firstcode[j - 9]; + primary = 0x100; + secondary = 0; + secondary_bits = 0; + for (i = 0; i < jcnt; ++i) + { + uint16_t tval; + size_t ind; + unsigned int incr; + + if ((code & 0xff) != primary) + { + uint16_t tprimary; + + /* Fill in a new primary table entry. */ + + primary = code & 0xff; + + tprimary = table[primary]; + if (tprimary == 0) + { + /* Start a new secondary table. */ + + if (unlikely ((next_secondary & HUFFMAN_VALUE_MASK) + != next_secondary)) + { + elf_zlib_failed (); + return 0; + } + + secondary = next_secondary; + secondary_bits = j - 8; + next_secondary += 1 << secondary_bits; + table[primary] = (secondary + + ((j - 8) << HUFFMAN_BITS_SHIFT) + + (1U << HUFFMAN_SECONDARY_SHIFT)); + } + else + { + /* There is an existing entry. It had better be a + secondary table with enough bits. */ + if (unlikely ((tprimary & (1U << HUFFMAN_SECONDARY_SHIFT)) + == 0)) + { + elf_zlib_failed (); + return 0; + } + secondary = tprimary & HUFFMAN_VALUE_MASK; + secondary_bits = ((tprimary >> HUFFMAN_BITS_SHIFT) + & HUFFMAN_BITS_MASK); + if (unlikely (secondary_bits < j - 8)) + { + elf_zlib_failed (); + return 0; + } + } + } + + /* Fill in secondary table entries. */ + + tval = val | ((j - 8) << HUFFMAN_BITS_SHIFT); + + for (ind = code >> 8; + ind < (1U << secondary_bits); + ind += 1U << (j - 8)) + { + if (unlikely (table[secondary + 0x100 + ind] != 0)) + { + elf_zlib_failed (); + return 0; + } + table[secondary + 0x100 + ind] = tval; + } + + if (i + 1 < jcnt) + val = next[val]; + + incr = 1U << (j - 1); + while ((code & incr) != 0) + incr >>= 1; + if (incr == 0) + code = 0; + else + { + code &= incr - 1; + code += incr; + } + } + } + +#ifdef BACKTRACE_GENERATE_FIXED_HUFFMAN_TABLE + final_next_secondary = next_secondary; +#endif + + return 1; +} + +#ifdef BACKTRACE_GENERATE_FIXED_HUFFMAN_TABLE + +/* Used to generate the fixed Huffman table for block type 1. */ + +#include <stdio.h> + +static uint16_t table[ZDEBUG_TABLE_SIZE]; +static unsigned char codes[287]; + +int +main () +{ + size_t i; + + for (i = 0; i <= 143; ++i) + codes[i] = 8; + for (i = 144; i <= 255; ++i) + codes[i] = 9; + for (i = 256; i <= 279; ++i) + codes[i] = 7; + for (i = 280; i <= 287; ++i) + codes[i] = 8; + if (!elf_zlib_inflate_table (&codes[0], 287, &table[0], &table[0])) + { + fprintf (stderr, "elf_zlib_inflate_table failed\n"); + exit (EXIT_FAILURE); + } + + printf ("static const uint16_t elf_zlib_default_table[%#zx] =\n", + final_next_secondary + 0x100); + printf ("{\n"); + for (i = 0; i < final_next_secondary + 0x100; i += 8) + { + size_t j; + + printf (" "); + for (j = i; j < final_next_secondary + 0x100 && j < i + 8; ++j) + printf (" %#x,", table[j]); + printf ("\n"); + } + printf ("};\n"); + return 0; +} + +#endif + +/* The fixed table generated by the #ifdef'ed out main function + above. */ + +static const uint16_t elf_zlib_default_table[0x170] = +{ + 0xd00, 0xe50, 0xe10, 0xf18, 0xd10, 0xe70, 0xe30, 0x1232, + 0xd08, 0xe60, 0xe20, 0x1212, 0xe00, 0xe80, 0xe40, 0x1252, + 0xd04, 0xe58, 0xe18, 0x1202, 0xd14, 0xe78, 0xe38, 0x1242, + 0xd0c, 0xe68, 0xe28, 0x1222, 0xe08, 0xe88, 0xe48, 0x1262, + 0xd02, 0xe54, 0xe14, 0xf1c, 0xd12, 0xe74, 0xe34, 0x123a, + 0xd0a, 0xe64, 0xe24, 0x121a, 0xe04, 0xe84, 0xe44, 0x125a, + 0xd06, 0xe5c, 0xe1c, 0x120a, 0xd16, 0xe7c, 0xe3c, 0x124a, + 0xd0e, 0xe6c, 0xe2c, 0x122a, 0xe0c, 0xe8c, 0xe4c, 0x126a, + 0xd01, 0xe52, 0xe12, 0xf1a, 0xd11, 0xe72, 0xe32, 0x1236, + 0xd09, 0xe62, 0xe22, 0x1216, 0xe02, 0xe82, 0xe42, 0x1256, + 0xd05, 0xe5a, 0xe1a, 0x1206, 0xd15, 0xe7a, 0xe3a, 0x1246, + 0xd0d, 0xe6a, 0xe2a, 0x1226, 0xe0a, 0xe8a, 0xe4a, 0x1266, + 0xd03, 0xe56, 0xe16, 0xf1e, 0xd13, 0xe76, 0xe36, 0x123e, + 0xd0b, 0xe66, 0xe26, 0x121e, 0xe06, 0xe86, 0xe46, 0x125e, + 0xd07, 0xe5e, 0xe1e, 0x120e, 0xd17, 0xe7e, 0xe3e, 0x124e, + 0xd0f, 0xe6e, 0xe2e, 0x122e, 0xe0e, 0xe8e, 0xe4e, 0x126e, + 0xd00, 0xe51, 0xe11, 0xf19, 0xd10, 0xe71, 0xe31, 0x1234, + 0xd08, 0xe61, 0xe21, 0x1214, 0xe01, 0xe81, 0xe41, 0x1254, + 0xd04, 0xe59, 0xe19, 0x1204, 0xd14, 0xe79, 0xe39, 0x1244, + 0xd0c, 0xe69, 0xe29, 0x1224, 0xe09, 0xe89, 0xe49, 0x1264, + 0xd02, 0xe55, 0xe15, 0xf1d, 0xd12, 0xe75, 0xe35, 0x123c, + 0xd0a, 0xe65, 0xe25, 0x121c, 0xe05, 0xe85, 0xe45, 0x125c, + 0xd06, 0xe5d, 0xe1d, 0x120c, 0xd16, 0xe7d, 0xe3d, 0x124c, + 0xd0e, 0xe6d, 0xe2d, 0x122c, 0xe0d, 0xe8d, 0xe4d, 0x126c, + 0xd01, 0xe53, 0xe13, 0xf1b, 0xd11, 0xe73, 0xe33, 0x1238, + 0xd09, 0xe63, 0xe23, 0x1218, 0xe03, 0xe83, 0xe43, 0x1258, + 0xd05, 0xe5b, 0xe1b, 0x1208, 0xd15, 0xe7b, 0xe3b, 0x1248, + 0xd0d, 0xe6b, 0xe2b, 0x1228, 0xe0b, 0xe8b, 0xe4b, 0x1268, + 0xd03, 0xe57, 0xe17, 0x1200, 0xd13, 0xe77, 0xe37, 0x1240, + 0xd0b, 0xe67, 0xe27, 0x1220, 0xe07, 0xe87, 0xe47, 0x1260, + 0xd07, 0xe5f, 0xe1f, 0x1210, 0xd17, 0xe7f, 0xe3f, 0x1250, + 0xd0f, 0xe6f, 0xe2f, 0x1230, 0xe0f, 0xe8f, 0xe4f, 0, + 0x290, 0x291, 0x292, 0x293, 0x294, 0x295, 0x296, 0x297, + 0x298, 0x299, 0x29a, 0x29b, 0x29c, 0x29d, 0x29e, 0x29f, + 0x2a0, 0x2a1, 0x2a2, 0x2a3, 0x2a4, 0x2a5, 0x2a6, 0x2a7, + 0x2a8, 0x2a9, 0x2aa, 0x2ab, 0x2ac, 0x2ad, 0x2ae, 0x2af, + 0x2b0, 0x2b1, 0x2b2, 0x2b3, 0x2b4, 0x2b5, 0x2b6, 0x2b7, + 0x2b8, 0x2b9, 0x2ba, 0x2bb, 0x2bc, 0x2bd, 0x2be, 0x2bf, + 0x2c0, 0x2c1, 0x2c2, 0x2c3, 0x2c4, 0x2c5, 0x2c6, 0x2c7, + 0x2c8, 0x2c9, 0x2ca, 0x2cb, 0x2cc, 0x2cd, 0x2ce, 0x2cf, + 0x2d0, 0x2d1, 0x2d2, 0x2d3, 0x2d4, 0x2d5, 0x2d6, 0x2d7, + 0x2d8, 0x2d9, 0x2da, 0x2db, 0x2dc, 0x2dd, 0x2de, 0x2df, + 0x2e0, 0x2e1, 0x2e2, 0x2e3, 0x2e4, 0x2e5, 0x2e6, 0x2e7, + 0x2e8, 0x2e9, 0x2ea, 0x2eb, 0x2ec, 0x2ed, 0x2ee, 0x2ef, + 0x2f0, 0x2f1, 0x2f2, 0x2f3, 0x2f4, 0x2f5, 0x2f6, 0x2f7, + 0x2f8, 0x2f9, 0x2fa, 0x2fb, 0x2fc, 0x2fd, 0x2fe, 0x2ff, +}; + +/* Inflate a zlib stream from PIN/SIN to POUT/SOUT. Return 1 on + success, 0 on some error parsing the stream. */ + +static int +elf_zlib_inflate (const unsigned char *pin, size_t sin, uint16_t *zdebug_table, + unsigned char *pout, size_t sout) +{ + unsigned char *porigout; + const unsigned char *pinend; + unsigned char *poutend; + + /* We can apparently see multiple zlib streams concatenated + together, so keep going as long as there is something to read. + The last 4 bytes are the checksum. */ + porigout = pout; + pinend = pin + sin; + poutend = pout + sout; + while ((pinend - pin) > 4) + { + uint32_t val; + unsigned int bits; + int last; + + /* Read the two byte zlib header. */ + + if (unlikely ((pin[0] & 0xf) != 8)) /* 8 is zlib encoding. */ + { + /* Unknown compression method. */ + elf_zlib_failed (); + return 0; + } + if (unlikely ((pin[0] >> 4) > 7)) + { + /* Window size too large. Other than this check, we don't + care about the window size. */ + elf_zlib_failed (); + return 0; + } + if (unlikely ((pin[1] & 0x20) != 0)) + { + /* Stream expects a predefined dictionary, but we have no + dictionary. */ + elf_zlib_failed (); + return 0; + } + val = (pin[0] << 8) | pin[1]; + if (unlikely (val % 31 != 0)) + { + /* Header check failure. */ + elf_zlib_failed (); + return 0; + } + pin += 2; + + /* Read blocks until one is marked last. */ + + val = 0; + bits = 0; + last = 0; + + while (!last) + { + unsigned int type; + const uint16_t *tlit; + const uint16_t *tdist; + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + last = val & 1; + type = (val >> 1) & 3; + val >>= 3; + bits -= 3; + + if (unlikely (type == 3)) + { + /* Invalid block type. */ + elf_zlib_failed (); + return 0; + } + + if (type == 0) + { + uint16_t len; + uint16_t lenc; + + /* An uncompressed block. */ + + /* If we've read ahead more than a byte, back up. */ + while (bits > 8) + { + --pin; + bits -= 8; + } + + val = 0; + bits = 0; + if (unlikely ((pinend - pin) < 4)) + { + /* Missing length. */ + elf_zlib_failed (); + return 0; + } + len = pin[0] | (pin[1] << 8); + lenc = pin[2] | (pin[3] << 8); + pin += 4; + lenc = ~lenc; + if (unlikely (len != lenc)) + { + /* Corrupt data. */ + elf_zlib_failed (); + return 0; + } + if (unlikely (len > (unsigned int) (pinend - pin) + || len > (unsigned int) (poutend - pout))) + { + /* Not enough space in buffers. */ + elf_zlib_failed (); + return 0; + } + memcpy (pout, pin, len); + pout += len; + pin += len; + + /* Go around to read the next block. */ + continue; + } + + if (type == 1) + { + tlit = elf_zlib_default_table; + tdist = elf_zlib_default_table; + } + else + { + unsigned int nlit; + unsigned int ndist; + unsigned int nclen; + unsigned char codebits[19]; + unsigned char *plenbase; + unsigned char *plen; + unsigned char *plenend; + + /* Read a Huffman encoding table. The various magic + numbers here are from RFC 1951. */ + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + nlit = (val & 0x1f) + 257; + val >>= 5; + ndist = (val & 0x1f) + 1; + val >>= 5; + nclen = (val & 0xf) + 4; + val >>= 4; + bits -= 14; + if (unlikely (nlit > 286 || ndist > 30)) + { + /* Values out of range. */ + elf_zlib_failed (); + return 0; + } + + /* Read and build the table used to compress the + literal, length, and distance codes. */ + + memset(&codebits[0], 0, 19); + + /* There are always at least 4 elements in the + table. */ + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + codebits[16] = val & 7; + codebits[17] = (val >> 3) & 7; + codebits[18] = (val >> 6) & 7; + codebits[0] = (val >> 9) & 7; + val >>= 12; + bits -= 12; + + if (nclen == 4) + goto codebitsdone; + + codebits[8] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 5) + goto codebitsdone; + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + codebits[7] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 6) + goto codebitsdone; + + codebits[9] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 7) + goto codebitsdone; + + codebits[6] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 8) + goto codebitsdone; + + codebits[10] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 9) + goto codebitsdone; + + codebits[5] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 10) + goto codebitsdone; + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + codebits[11] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 11) + goto codebitsdone; + + codebits[4] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 12) + goto codebitsdone; + + codebits[12] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 13) + goto codebitsdone; + + codebits[3] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 14) + goto codebitsdone; + + codebits[13] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 15) + goto codebitsdone; + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + codebits[2] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 16) + goto codebitsdone; + + codebits[14] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 17) + goto codebitsdone; + + codebits[1] = val & 7; + val >>= 3; + bits -= 3; + + if (nclen == 18) + goto codebitsdone; + + codebits[15] = val & 7; + val >>= 3; + bits -= 3; + + codebitsdone: + + if (!elf_zlib_inflate_table (codebits, 19, zdebug_table, + zdebug_table)) + return 0; + + /* Read the compressed bit lengths of the literal, + length, and distance codes. We have allocated space + at the end of zdebug_table to hold them. */ + + plenbase = (((unsigned char *) zdebug_table) + + ZDEBUG_TABLE_CODELEN_OFFSET); + plen = plenbase; + plenend = plen + nlit + ndist; + while (plen < plenend) + { + uint16_t t; + unsigned int b; + uint16_t v; + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + t = zdebug_table[val & 0xff]; + + /* The compression here uses bit lengths up to 7, so + a secondary table is never necessary. */ + if (unlikely ((t & (1U << HUFFMAN_SECONDARY_SHIFT)) != 0)) + { + elf_zlib_failed (); + return 0; + } + + b = (t >> HUFFMAN_BITS_SHIFT) & HUFFMAN_BITS_MASK; + val >>= b + 1; + bits -= b + 1; + + v = t & HUFFMAN_VALUE_MASK; + if (v < 16) + *plen++ = v; + else if (v == 16) + { + unsigned int c; + unsigned int prev; + + /* Copy previous entry 3 to 6 times. */ + + if (unlikely (plen == plenbase)) + { + elf_zlib_failed (); + return 0; + } + + /* We used up to 7 bits since the last + elf_zlib_fetch, so we have at least 8 bits + available here. */ + + c = 3 + (val & 0x3); + val >>= 2; + bits -= 2; + if (unlikely ((unsigned int) (plenend - plen) < c)) + { + elf_zlib_failed (); + return 0; + } + + prev = plen[-1]; + switch (c) + { + case 6: + *plen++ = prev; + /* fallthrough */ + case 5: + *plen++ = prev; + /* fallthrough */ + case 4: + *plen++ = prev; + } + *plen++ = prev; + *plen++ = prev; + *plen++ = prev; + } + else if (v == 17) + { + unsigned int c; + + /* Store zero 3 to 10 times. */ + + /* We used up to 7 bits since the last + elf_zlib_fetch, so we have at least 8 bits + available here. */ + + c = 3 + (val & 0x7); + val >>= 3; + bits -= 3; + if (unlikely ((unsigned int) (plenend - plen) < c)) + { + elf_zlib_failed (); + return 0; + } + + switch (c) + { + case 10: + *plen++ = 0; + /* fallthrough */ + case 9: + *plen++ = 0; + /* fallthrough */ + case 8: + *plen++ = 0; + /* fallthrough */ + case 7: + *plen++ = 0; + /* fallthrough */ + case 6: + *plen++ = 0; + /* fallthrough */ + case 5: + *plen++ = 0; + /* fallthrough */ + case 4: + *plen++ = 0; + } + *plen++ = 0; + *plen++ = 0; + *plen++ = 0; + } + else if (v == 18) + { + unsigned int c; + + /* Store zero 11 to 138 times. */ + + /* We used up to 7 bits since the last + elf_zlib_fetch, so we have at least 8 bits + available here. */ + + c = 11 + (val & 0x7f); + val >>= 7; + bits -= 7; + if (unlikely ((unsigned int) (plenend - plen) < c)) + { + elf_zlib_failed (); + return 0; + } + + memset (plen, 0, c); + plen += c; + } + else + { + elf_zlib_failed (); + return 0; + } + } + + /* Make sure that the stop code can appear. */ + + plen = plenbase; + if (unlikely (plen[256] == 0)) + { + elf_zlib_failed (); + return 0; + } + + /* Build the decompression tables. */ + + if (!elf_zlib_inflate_table (plen, nlit, zdebug_table, + zdebug_table)) + return 0; + if (!elf_zlib_inflate_table (plen + nlit, ndist, zdebug_table, + zdebug_table + HUFFMAN_TABLE_SIZE)) + return 0; + tlit = zdebug_table; + tdist = zdebug_table + HUFFMAN_TABLE_SIZE; + } + + /* Inflate values until the end of the block. This is the + main loop of the inflation code. */ + + while (1) + { + uint16_t t; + unsigned int b; + uint16_t v; + unsigned int lit; + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + t = tlit[val & 0xff]; + b = (t >> HUFFMAN_BITS_SHIFT) & HUFFMAN_BITS_MASK; + v = t & HUFFMAN_VALUE_MASK; + + if ((t & (1U << HUFFMAN_SECONDARY_SHIFT)) == 0) + { + lit = v; + val >>= b + 1; + bits -= b + 1; + } + else + { + t = tlit[v + 0x100 + ((val >> 8) & ((1U << b) - 1))]; + b = (t >> HUFFMAN_BITS_SHIFT) & HUFFMAN_BITS_MASK; + lit = t & HUFFMAN_VALUE_MASK; + val >>= b + 8; + bits -= b + 8; + } + + if (lit < 256) + { + if (unlikely (pout == poutend)) + { + elf_zlib_failed (); + return 0; + } + + *pout++ = lit; + + /* We will need to write the next byte soon. We ask + for high temporal locality because we will write + to the whole cache line soon. */ + __builtin_prefetch (pout, 1, 3); + } + else if (lit == 256) + { + /* The end of the block. */ + break; + } + else + { + unsigned int dist; + unsigned int len; + + /* Convert lit into a length. */ + + if (lit < 265) + len = lit - 257 + 3; + else if (lit == 285) + len = 258; + else if (unlikely (lit > 285)) + { + elf_zlib_failed (); + return 0; + } + else + { + unsigned int extra; + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + /* This is an expression for the table of length + codes in RFC 1951 3.2.5. */ + lit -= 265; + extra = (lit >> 2) + 1; + len = (lit & 3) << extra; + len += 11; + len += ((1U << (extra - 1)) - 1) << 3; + len += val & ((1U << extra) - 1); + val >>= extra; + bits -= extra; + } + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + t = tdist[val & 0xff]; + b = (t >> HUFFMAN_BITS_SHIFT) & HUFFMAN_BITS_MASK; + v = t & HUFFMAN_VALUE_MASK; + + if ((t & (1U << HUFFMAN_SECONDARY_SHIFT)) == 0) + { + dist = v; + val >>= b + 1; + bits -= b + 1; + } + else + { + t = tdist[v + 0x100 + ((val >> 8) & ((1U << b) - 1))]; + b = (t >> HUFFMAN_BITS_SHIFT) & HUFFMAN_BITS_MASK; + dist = t & HUFFMAN_VALUE_MASK; + val >>= b + 8; + bits -= b + 8; + } + + /* Convert dist to a distance. */ + + if (dist == 0) + { + /* A distance of 1. A common case, meaning + repeat the last character LEN times. */ + + if (unlikely (pout == porigout)) + { + elf_zlib_failed (); + return 0; + } + + if (unlikely ((unsigned int) (poutend - pout) < len)) + { + elf_zlib_failed (); + return 0; + } + + memset (pout, pout[-1], len); + pout += len; + } + else if (unlikely (dist > 29)) + { + elf_zlib_failed (); + return 0; + } + else + { + if (dist < 4) + dist = dist + 1; + else + { + unsigned int extra; + + if (!elf_zlib_fetch (&pin, pinend, &val, &bits)) + return 0; + + /* This is an expression for the table of + distance codes in RFC 1951 3.2.5. */ + dist -= 4; + extra = (dist >> 1) + 1; + dist = (dist & 1) << extra; + dist += 5; + dist += ((1U << (extra - 1)) - 1) << 2; + dist += val & ((1U << extra) - 1); + val >>= extra; + bits -= extra; + } + + /* Go back dist bytes, and copy len bytes from + there. */ + + if (unlikely ((unsigned int) (pout - porigout) < dist)) + { + elf_zlib_failed (); + return 0; + } + + if (unlikely ((unsigned int) (poutend - pout) < len)) + { + elf_zlib_failed (); + return 0; + } + + if (dist >= len) + { + memcpy (pout, pout - dist, len); + pout += len; + } + else + { + while (len > 0) + { + unsigned int copy; + + copy = len < dist ? len : dist; + memcpy (pout, pout - dist, copy); + len -= copy; + pout += copy; + } + } + } + } + } + } + } + + /* We should have filled the output buffer. */ + if (unlikely (pout != poutend)) + { + elf_zlib_failed (); + return 0; + } + + return 1; +} + +/* Verify the zlib checksum. The checksum is in the 4 bytes at + CHECKBYTES, and the uncompressed data is at UNCOMPRESSED / + UNCOMPRESSED_SIZE. Returns 1 on success, 0 on failure. */ + +static int +elf_zlib_verify_checksum (const unsigned char *checkbytes, + const unsigned char *uncompressed, + size_t uncompressed_size) +{ + unsigned int i; + unsigned int cksum; + const unsigned char *p; + uint32_t s1; + uint32_t s2; + size_t hsz; + + cksum = 0; + for (i = 0; i < 4; i++) + cksum = (cksum << 8) | checkbytes[i]; + + s1 = 1; + s2 = 0; + + /* Minimize modulo operations. */ + + p = uncompressed; + hsz = uncompressed_size; + while (hsz >= 5552) + { + for (i = 0; i < 5552; i += 16) + { + /* Manually unroll loop 16 times. */ + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + } + hsz -= 5552; + s1 %= 65521; + s2 %= 65521; + } + + while (hsz >= 16) + { + /* Manually unroll loop 16 times. */ + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + s1 = s1 + *p++; + s2 = s2 + s1; + + hsz -= 16; + } + + for (i = 0; i < hsz; ++i) + { + s1 = s1 + *p++; + s2 = s2 + s1; + } + + s1 %= 65521; + s2 %= 65521; + + if (unlikely ((s2 << 16) + s1 != cksum)) + { + elf_zlib_failed (); + return 0; + } + + return 1; +} + +/* Inflate a zlib stream from PIN/SIN to POUT/SOUT, and verify the + checksum. Return 1 on success, 0 on error. */ + +static int +elf_zlib_inflate_and_verify (const unsigned char *pin, size_t sin, + uint16_t *zdebug_table, unsigned char *pout, + size_t sout) +{ + if (!elf_zlib_inflate (pin, sin, zdebug_table, pout, sout)) + return 0; + if (!elf_zlib_verify_checksum (pin + sin - 4, pout, sout)) + return 0; + return 1; +} + +/* Uncompress the old compressed debug format, the one emitted by + --compress-debug-sections=zlib-gnu. The compressed data is in + COMPRESSED / COMPRESSED_SIZE, and the function writes to + *UNCOMPRESSED / *UNCOMPRESSED_SIZE. ZDEBUG_TABLE is work space to + hold Huffman tables. Returns 0 on error, 1 on successful + decompression or if something goes wrong. In general we try to + carry on, by returning 1, even if we can't decompress. */ + +static int +elf_uncompress_zdebug (struct backtrace_state *state, + const unsigned char *compressed, size_t compressed_size, + uint16_t *zdebug_table, + backtrace_error_callback error_callback, void *data, + unsigned char **uncompressed, size_t *uncompressed_size) +{ + size_t sz; + size_t i; + unsigned char *po; + + *uncompressed = NULL; + *uncompressed_size = 0; + + /* The format starts with the four bytes ZLIB, followed by the 8 + byte length of the uncompressed data in big-endian order, + followed by a zlib stream. */ + + if (compressed_size < 12 || memcmp (compressed, "ZLIB", 4) != 0) + return 1; + + sz = 0; + for (i = 0; i < 8; i++) + sz = (sz << 8) | compressed[i + 4]; + + if (*uncompressed != NULL && *uncompressed_size >= sz) + po = *uncompressed; + else + { + po = (unsigned char *) backtrace_alloc (state, sz, error_callback, data); + if (po == NULL) + return 0; + } + + if (!elf_zlib_inflate_and_verify (compressed + 12, compressed_size - 12, + zdebug_table, po, sz)) + return 1; + + *uncompressed = po; + *uncompressed_size = sz; + + return 1; +} + +/* Uncompress the new compressed debug format, the official standard + ELF approach emitted by --compress-debug-sections=zlib-gabi. The + compressed data is in COMPRESSED / COMPRESSED_SIZE, and the + function writes to *UNCOMPRESSED / *UNCOMPRESSED_SIZE. + ZDEBUG_TABLE is work space as for elf_uncompress_zdebug. Returns 0 + on error, 1 on successful decompression or if something goes wrong. + In general we try to carry on, by returning 1, even if we can't + decompress. */ + +static int +elf_uncompress_chdr (struct backtrace_state *state, + const unsigned char *compressed, size_t compressed_size, + uint16_t *zdebug_table, + backtrace_error_callback error_callback, void *data, + unsigned char **uncompressed, size_t *uncompressed_size) +{ + const b_elf_chdr *chdr; + unsigned char *po; + + *uncompressed = NULL; + *uncompressed_size = 0; + + /* The format starts with an ELF compression header. */ + if (compressed_size < sizeof (b_elf_chdr)) + return 1; + + chdr = (const b_elf_chdr *) compressed; + + if (chdr->ch_type != ELFCOMPRESS_ZLIB) + { + /* Unsupported compression algorithm. */ + return 1; + } + + if (*uncompressed != NULL && *uncompressed_size >= chdr->ch_size) + po = *uncompressed; + else + { + po = (unsigned char *) backtrace_alloc (state, chdr->ch_size, + error_callback, data); + if (po == NULL) + return 0; + } + + if (!elf_zlib_inflate_and_verify (compressed + sizeof (b_elf_chdr), + compressed_size - sizeof (b_elf_chdr), + zdebug_table, po, chdr->ch_size)) + return 1; + + *uncompressed = po; + *uncompressed_size = chdr->ch_size; + + return 1; +} + +/* This function is a hook for testing the zlib support. It is only + used by tests. */ + +int +backtrace_uncompress_zdebug (struct backtrace_state *state, + const unsigned char *compressed, + size_t compressed_size, + backtrace_error_callback error_callback, + void *data, unsigned char **uncompressed, + size_t *uncompressed_size) +{ + uint16_t *zdebug_table; + int ret; + + zdebug_table = ((uint16_t *) backtrace_alloc (state, ZDEBUG_TABLE_SIZE, + error_callback, data)); + if (zdebug_table == NULL) + return 0; + ret = elf_uncompress_zdebug (state, compressed, compressed_size, + zdebug_table, error_callback, data, + uncompressed, uncompressed_size); + backtrace_free (state, zdebug_table, ZDEBUG_TABLE_SIZE, + error_callback, data); + return ret; +} + /* Add the backtrace data for one ELF file. Returns 1 on success, 0 on failure (in both cases descriptor is closed) or -1 if exe is non-zero and the ELF file is ET_DYN, which tells the caller that @@ -1011,6 +2548,8 @@ elf_add (struct backtrace_state *state, const char *filename, int descriptor, off_t max_offset; struct backtrace_view debug_view; int debug_view_valid; + unsigned int using_debug_view; + uint16_t *zdebug_table; *found_sym = 0; *found_dwarf = 0; @@ -1174,6 +2713,7 @@ elf_add (struct backtrace_state *state, const char *filename, int descriptor, { sections[j].offset = shdr->sh_offset; sections[j].size = shdr->sh_size; + sections[j].compressed = (shdr->sh_flags & SHF_COMPRESSED) != 0; break; } } @@ -1284,8 +2824,6 @@ elf_add (struct backtrace_state *state, const char *filename, int descriptor, elf_add_syminfo_data (state, sdata); } - /* FIXME: Need to handle compressed debug sections. */ - backtrace_release_view (state, &shdrs_view, error_callback, data); shdrs_view_valid = 0; backtrace_release_view (state, &names_view, error_callback, data); @@ -1373,13 +2911,94 @@ elf_add (struct backtrace_state *state, const char *filename, int descriptor, goto fail; descriptor = -1; + using_debug_view = 0; for (i = 0; i < (int) DEBUG_MAX; ++i) { if (sections[i].size == 0) sections[i].data = NULL; else - sections[i].data = ((const unsigned char *) debug_view.data - + (sections[i].offset - min_offset)); + { + sections[i].data = ((const unsigned char *) debug_view.data + + (sections[i].offset - min_offset)); + if (i < ZDEBUG_INFO) + ++using_debug_view; + } + } + + /* Uncompress the old format (--compress-debug-sections=zlib-gnu). */ + + zdebug_table = NULL; + for (i = 0; i < ZDEBUG_INFO; ++i) + { + struct debug_section_info *pz; + + pz = §ions[i + ZDEBUG_INFO - DEBUG_INFO]; + if (sections[i].size == 0 && pz->size > 0) + { + unsigned char *uncompressed_data; + size_t uncompressed_size; + + if (zdebug_table == NULL) + { + zdebug_table = ((uint16_t *) + backtrace_alloc (state, ZDEBUG_TABLE_SIZE, + error_callback, data)); + if (zdebug_table == NULL) + goto fail; + } + + uncompressed_data = NULL; + uncompressed_size = 0; + if (!elf_uncompress_zdebug (state, pz->data, pz->size, zdebug_table, + error_callback, data, + &uncompressed_data, &uncompressed_size)) + goto fail; + sections[i].data = uncompressed_data; + sections[i].size = uncompressed_size; + sections[i].compressed = 0; + } + } + + /* Uncompress the official ELF format + (--compress-debug-sections=zlib-gabi). */ + for (i = 0; i < ZDEBUG_INFO; ++i) + { + unsigned char *uncompressed_data; + size_t uncompressed_size; + + if (sections[i].size == 0 || !sections[i].compressed) + continue; + + if (zdebug_table == NULL) + { + zdebug_table = ((uint16_t *) + backtrace_alloc (state, ZDEBUG_TABLE_SIZE, + error_callback, data)); + if (zdebug_table == NULL) + goto fail; + } + + uncompressed_data = NULL; + uncompressed_size = 0; + if (!elf_uncompress_chdr (state, sections[i].data, sections[i].size, + zdebug_table, error_callback, data, + &uncompressed_data, &uncompressed_size)) + goto fail; + sections[i].data = uncompressed_data; + sections[i].size = uncompressed_size; + sections[i].compressed = 0; + + --using_debug_view; + } + + if (zdebug_table != NULL) + backtrace_free (state, zdebug_table, ZDEBUG_TABLE_SIZE, + error_callback, data); + + if (debug_view_valid && using_debug_view == 0) + { + backtrace_release_view (state, &debug_view, error_callback, data); + debug_view_valid = 0; } if (!backtrace_dwarf_add (state, base_address, |