DbgHelp: Add Support for .gnu_debuglink
Robert Shearman
rob at codeweavers.com
Sun Oct 3 17:23:37 CDT 2004
Hi,
This patch adds support for the .gnu_debuglink feature which allows an
ELF module to specifiy another ELF module that contains its debugging
information, thus removing a disadvantage of using stripped builds.
If you want to test the .gnu_debuglink feature then you need to perform
the following steps:
1. Compile the module (e.g. notepad.exe.so)
2. objcopy --only-keep-debug notepad.exe.so notepad.exe.so.debug
3. objcopy --strip-debug notepad.exe.so
4. objcopy --add-gnu-debuglink=notepad.exe.so.debug notepad.exe.so
This patch has been ack'ed by Eric.
Rob
Changelog:
Add support for .gnu_debuglink.
-------------- next part --------------
Index: wine/dlls/dbghelp/elf_module.c
===================================================================
RCS file: /home/wine/wine/dlls/dbghelp/elf_module.c,v
retrieving revision 1.9
diff -u -p -r1.9 elf_module.c
--- wine/dlls/dbghelp/elf_module.c 30 Aug 2004 19:31:14 -0000 1.9
+++ wine/dlls/dbghelp/elf_module.c 29 Sep 2004 23:46:18 -0000
@@ -459,19 +459,139 @@ static int elf_new_public_symbols(struct
return TRUE;
}
+/* Copyright (C) 1986 Gary S. Brown. Modified by Robert Shearman. You may use
+ the following calc_crc32 code or tables extracted from it, as desired without
+ restriction. */
+
+/**********************************************************************\
+|* Demonstration program to compute the 32-bit CRC used as the frame *|
+|* check sequence in ADCCP (ANSI X3.66, also known as FIPS PUB 71 *|
+|* and FED-STD-1003, the U.S. versions of CCITT's X.25 link-level *|
+|* protocol). The 32-bit FCS was added via the Federal Register, *|
+|* 1 June 1982, p.23798. I presume but don't know for certain that *|
+|* this polynomial is or will be included in CCITT V.41, which *|
+|* defines the 16-bit CRC (often called CRC-CCITT) polynomial. FIPS *|
+|* PUB 78 says that the 32-bit FCS reduces otherwise undetected *|
+|* errors by a factor of 10^-5 over 16-bit FCS. *|
+\**********************************************************************/
+
+/* First, the polynomial itself and its table of feedback terms. The */
+/* polynomial is */
+/* X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0 */
+/* Note that we take it "backwards" and put the highest-order term in */
+/* the lowest-order bit. The X^32 term is "implied"; the LSB is the */
+/* X^31 term, etc. The X^0 term (usually shown as "+1") results in */
+/* the MSB being 1. */
+
+/* Note that the usual hardware shift register implementation, which */
+/* is what we're using (we're merely optimizing it by doing eight-bit */
+/* chunks at a time) shifts bits into the lowest-order term. In our */
+/* implementation, that means shifting towards the right. Why do we */
+/* do it this way? Because the calculated CRC must be transmitted in */
+/* order from highest-order term to lowest-order term. UARTs transmit */
+/* characters in order from LSB to MSB. By storing the CRC this way, */
+/* we hand it to the UART in the order low-byte to high-byte; the UART */
+/* sends each low-bit to hight-bit; and the result is transmission bit */
+/* by bit from highest- to lowest-order term without requiring any bit */
+/* shuffling on our part. Reception works similarly. */
+
+/* The feedback terms table consists of 256, 32-bit entries. Notes: */
+/* */
+/* 1. The table can be generated at runtime if desired; code to do so */
+/* is shown later. It might not be obvious, but the feedback */
+/* terms simply represent the results of eight shift/xor opera- */
+/* tions for all combinations of data and CRC register values. */
+/* */
+/* 2. The CRC accumulation logic is the same for all CRC polynomials, */
+/* be they sixteen or thirty-two bits wide. You simply choose the */
+/* appropriate table. Alternatively, because the table can be */
+/* generated at runtime, you can start by generating the table for */
+/* the polynomial in question and use exactly the same "updcrc", */
+/* if your application needn't simultaneously handle two CRC */
+/* polynomials. (Note, however, that XMODEM is strange.) */
+/* */
+/* 3. For 16-bit CRCs, the table entries need be only 16 bits wide; */
+/* of course, 32-bit entries work OK if the high 16 bits are zero. */
+/* */
+/* 4. The values must be right-shifted by eight bits by the "updcrc" */
+/* logic; the shift must be unsigned (bring in zeroes). On some */
+/* hardware you could probably optimize the shift in assembler by */
+/* using byte-swap instructions. */
+
+
+static DWORD calc_crc32(const unsigned char *buf, size_t len)
+{
+#define UPDC32(octet,crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))
+ static const DWORD crc_32_tab[] =
+ { /* CRC polynomial 0xedb88320 */
+ 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
+ 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+ 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
+ 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+ 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+ 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+ 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
+ 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+ 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
+ 0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+ 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
+ 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+ 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
+ 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+ 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+ 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+ 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
+ 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+ 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
+ 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+ 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
+ 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+ 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
+ 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+ 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+ 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+ 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
+ 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+ 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
+ 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+ 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
+ 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+ 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
+ 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+ 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+ 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+ 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
+ 0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+ 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
+ 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+ 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
+ 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+ 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+ };
+ size_t i;
+ DWORD crc = ~0;
+ for(i = 0; i < len; i++)
+ crc = UPDC32(buf[i], crc);
+ return ~crc;
+#undef UPDC32
+}
+
+
/******************************************************************
- * elf_load_debug_info
+ * elf_load_debug_info_from_file
*
- * Loads the symbolic information from ELF module stored in 'filename'
+ * Loads the symbolic information from ELF module stored in 'file'
* the module has been loaded at 'load_offset' address, so symbols' address
- * relocation is performed
+ * relocation is performed. crc optionally points to the CRC of the debug file
+ * to load.
* returns
- * -1 if the file cannot be found/opened
* 0 if the file doesn't contain symbolic info (or this info cannot be
* read or parsed)
* 1 on success
*/
-BOOL elf_load_debug_info(struct module* module)
+static BOOL elf_load_debug_info_from_file(
+ struct module* module, const char* file, struct pool* pool,
+ struct hash_table* ht_symtab, const DWORD *crc)
{
BOOL ret = FALSE;
char* addr = (char*)0xffffffff;
@@ -481,9 +601,7 @@ BOOL elf_load_debug_info(struct module*
const Elf32_Shdr* spnt;
const char* shstrtab;
int i;
- int symtab_sect, dynsym_sect, stab_sect, stabstr_sect, debug_sect;
- struct pool pool;
- struct hash_table ht_symtab;
+ int symtab_sect, dynsym_sect, stab_sect, stabstr_sect, debug_sect, debuglink_sect;
struct thunk_area thunks[] =
{
{"__wine_spec_import_thunks", THUNK_ORDINAL_NOTYPE, 0, 0}, /* inter DLL calls */
@@ -502,15 +620,15 @@ BOOL elf_load_debug_info(struct module*
return FALSE;
}
- TRACE("%s\n", module->module.LoadedImageName);
+ TRACE("%s\n", file);
/* check that the file exists, and that the module hasn't been loaded yet */
- if (stat(module->module.LoadedImageName, &statbuf) == -1) goto leave;
+ if (stat(file, &statbuf) == -1) goto leave;
if (S_ISDIR(statbuf.st_mode)) goto leave;
/*
* Now open the file, so that we can mmap() it.
*/
- if ((fd = open(module->module.LoadedImageName, O_RDONLY)) == -1) goto leave;
+ if ((fd = open(file, O_RDONLY)) == -1) goto leave;
/*
* Now mmap() the file.
@@ -518,6 +636,13 @@ BOOL elf_load_debug_info(struct module*
addr = mmap(0, statbuf.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (addr == (char*)0xffffffff) goto leave;
+ if (crc && (*crc != calc_crc32(addr, statbuf.st_size)))
+ {
+ ERR("Bad CRC for file %s\n", file);
+ /* we don't tolerate mis-matched files */
+ goto leave;
+ }
+
/*
* Next, we need to find a few of the internal ELF headers within
* this thing. We need the main executable header, and the section
@@ -527,7 +652,7 @@ BOOL elf_load_debug_info(struct module*
spnt = (Elf32_Shdr*)(addr + ehptr->e_shoff);
shstrtab = (addr + spnt[ehptr->e_shstrndx].sh_offset);
- symtab_sect = dynsym_sect = stab_sect = stabstr_sect = debug_sect = -1;
+ symtab_sect = dynsym_sect = stab_sect = stabstr_sect = debug_sect = debuglink_sect = -1;
for (i = 0; i < ehptr->e_shnum; i++)
{
@@ -537,6 +662,8 @@ BOOL elf_load_debug_info(struct module*
stabstr_sect = i;
if (strcmp(shstrtab + spnt[i].sh_name, ".debug_info") == 0)
debug_sect = i;
+ if (strcmp(shstrtab + spnt[i].sh_name, ".gnu_debuglink") == 0)
+ debuglink_sect = i;
if ((strcmp(shstrtab + spnt[i].sh_name, ".symtab") == 0) &&
(spnt[i].sh_type == SHT_SYMTAB))
symtab_sect = i;
@@ -556,12 +683,9 @@ BOOL elf_load_debug_info(struct module*
}
module->module.SymType = SymExport;
- /* FIXME: guess a better size from ELF info */
- pool_init(&pool, 65536);
- hash_table_init(&pool, &ht_symtab, 256);
/* create a hash table for the symtab */
- elf_hash_symtab(module, &pool, &ht_symtab, addr,
+ elf_hash_symtab(module, pool, ht_symtab, addr,
spnt + symtab_sect, spnt + spnt[symtab_sect].sh_link,
sizeof(thunks) / sizeof(thunks[0]), thunks);
@@ -580,26 +704,35 @@ BOOL elf_load_debug_info(struct module*
goto leave;
}
/* and fill in the missing information for stabs */
- elf_finish_stabs_info(module, &ht_symtab);
+ elf_finish_stabs_info(module, ht_symtab);
}
else if (debug_sect != -1)
{
/* Dwarf 2 debug information */
FIXME("Unsupported Dwarf2 information for %s\n", module->module.ModuleName);
}
+ else if (debuglink_sect != -1)
+ {
+ DWORD crc;
+ const char * file = (const char *)(addr + spnt[debuglink_sect].sh_offset);
+ /* crc is stored after the null terminated file string rounded
+ * up to the next 4 byte boundary */
+ crc = *(const DWORD *)(file + ((DWORD_PTR)(strlen(file) + 4) & ~3));
+ ret = elf_load_debug_info_from_file(module, file, pool, ht_symtab, &crc);
+ if (!ret)
+ WARN("Couldn't load linked debug file %s\n", file);
+ }
}
if (strstr(module->module.ModuleName, "<elf>") ||
!strcmp(module->module.ModuleName, "<wine-loader>"))
{
/* add the thunks for native libraries */
if (!(dbghelp_options & SYMOPT_PUBLICS_ONLY))
- elf_new_wine_thunks(module, &ht_symtab,
+ elf_new_wine_thunks(module, ht_symtab,
sizeof(thunks) / sizeof(thunks[0]), thunks);
}
/* add all the public symbols from symtab */
- if (elf_new_public_symbols(module, &ht_symtab) && !ret) ret = TRUE;
-
- pool_destroy(&pool);
+ if (elf_new_public_symbols(module, ht_symtab) && !ret) ret = TRUE;
leave:
if (addr != (char*)0xffffffff) munmap(addr, statbuf.st_size);
@@ -609,6 +742,29 @@ leave:
}
/******************************************************************
+ * elf_load_debug_info
+ *
+ * Loads ELF debugging information from the module image file.
+ */
+BOOL elf_load_debug_info(struct module* module)
+{
+ BOOL ret;
+ struct pool pool;
+ struct hash_table ht_symtab;
+
+ pool_init(&pool, 65536);
+ hash_table_init(&pool, &ht_symtab, 256);
+
+ ret = elf_load_debug_info_from_file(module,
+ module->module.LoadedImageName, &pool, &ht_symtab, NULL);
+
+ pool_destroy(&pool);
+
+ return ret;
+}
+
+
+/******************************************************************
* is_dt_flag_valid
* returns true iff the section tag is valid
*/
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