/**
* Queries symbol information by symbol name.
*
* @returns IPRT status code.
* @retval VERR_DBG_NO_SYMBOLS if there aren't any symbols.
* @retval VERR_SYMBOL_NOT_FOUND if no suitable symbol was found.
* @retval VERR_DBG_SYMBOL_NAME_OUT_OF_RANGE if the symbol name is too long or
* short.
* @retval VERR_NO_MEMORY if RTDbgSymbolAlloc fails.
*
* @param hDbgMod The module handle.
* @param pszSymbol The symbol name.
* @param ppSymInfo Where to store the pointer to the returned
* symbol information. Always set. Free with
* RTDbgSymbolFree.
*/
RTDECL(int) RTDbgModSymbolByNameA(RTDBGMOD hDbgMod, const char *pszSymbol, PRTDBGSYMBOL *ppSymInfo)
{
AssertPtr(ppSymInfo);
*ppSymInfo = NULL;
PRTDBGSYMBOL pSymInfo = RTDbgSymbolAlloc();
if (!pSymInfo)
return VERR_NO_MEMORY;
int rc = RTDbgModSymbolByName(hDbgMod, pszSymbol, pSymInfo);
if (RT_SUCCESS(rc))
*ppSymInfo = pSymInfo;
else
RTDbgSymbolFree(pSymInfo);
return rc;
}
/**
* @interface_method_impl{DBGFOSIDMESG,pfnQueryKernelLog}
*/
static DECLCALLBACK(int) dbgDiggerLinuxIDmsg_QueryKernelLog(PDBGFOSIDMESG pThis, PUVM pUVM, uint32_t fFlags, uint32_t cMessages,
char *pszBuf, size_t cbBuf, size_t *pcbActual)
{
PDBGDIGGERLINUX pData = RT_FROM_MEMBER(pThis, DBGDIGGERLINUX, IDmesg);
if (cMessages < 1)
return VERR_INVALID_PARAMETER;
/*
* Resolve the symbols we need and read their values.
*/
RTDBGAS hAs = DBGFR3AsResolveAndRetain(pUVM, DBGF_AS_KERNEL);
RTDBGMOD hMod;
int rc = RTDbgAsModuleByName(hAs, "vmlinux", 0, &hMod);
if (RT_FAILURE(rc))
return VERR_NOT_FOUND;
RTDbgAsRelease(hAs);
RTGCPTR GCPtrLogBuf;
uint32_t cbLogBuf;
uint32_t idxFirst;
uint32_t idxNext;
struct { void *pvVar; size_t cbHost, cbGuest; const char *pszSymbol; } aSymbols[] =
{
{ &GCPtrLogBuf, sizeof(GCPtrLogBuf), pData->f64Bit ? sizeof(uint64_t) : sizeof(uint32_t), "log_buf" },
{ &cbLogBuf, sizeof(cbLogBuf), sizeof(cbLogBuf), "log_buf_len" },
{ &idxFirst, sizeof(idxFirst), sizeof(idxFirst), "log_first_idx" },
{ &idxNext, sizeof(idxNext), sizeof(idxNext), "log_next_idx" },
};
for (uint32_t i = 0; i < RT_ELEMENTS(aSymbols); i++)
{
RTDBGSYMBOL SymInfo;
rc = RTDbgModSymbolByName(hMod, aSymbols[i].pszSymbol, &SymInfo);
if (RT_SUCCESS(rc))
{
RT_BZERO(aSymbols[i].pvVar, aSymbols[i].cbHost);
Assert(aSymbols[i].cbHost >= aSymbols[i].cbGuest);
DBGFADDRESS Addr;
rc = DBGFR3MemRead(pUVM, 0 /*idCpu*/,
DBGFR3AddrFromFlat(pUVM, &Addr, (RTGCPTR)SymInfo.Value + pData->AddrKernelBase.FlatPtr),
aSymbols[i].pvVar, aSymbols[i].cbGuest);
if (RT_SUCCESS(rc))
continue;
Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: Reading '%s' at %RGv: %Rrc\n", aSymbols[i].pszSymbol, Addr.FlatPtr, rc));
}
else
Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: Error looking up '%s': %Rrc\n", aSymbols[i].pszSymbol, rc));
RTDbgModRelease(hMod);
return VERR_NOT_FOUND;
}
/*
* Check if the values make sense.
*/
if (pData->f64Bit ? !LNX64_VALID_ADDRESS(GCPtrLogBuf) : !LNX32_VALID_ADDRESS(GCPtrLogBuf))
{
Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: 'log_buf' value %RGv is not valid.\n", GCPtrLogBuf));
return VERR_NOT_FOUND;
}
if ( cbLogBuf < 4096
|| !RT_IS_POWER_OF_TWO(cbLogBuf)
|| cbLogBuf > 16*_1M)
{
Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: 'log_buf_len' value %#x is not valid.\n", cbLogBuf));
return VERR_NOT_FOUND;
}
uint32_t const cbLogAlign = 4;
if ( idxFirst > cbLogBuf - sizeof(LNXPRINTKHDR)
|| (idxFirst & (cbLogAlign - 1)) != 0)
{
Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: 'log_first_idx' value %#x is not valid.\n", idxFirst));
return VERR_NOT_FOUND;
}
if ( idxNext > cbLogBuf - sizeof(LNXPRINTKHDR)
|| (idxNext & (cbLogAlign - 1)) != 0)
{
Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: 'log_next_idx' value %#x is not valid.\n", idxNext));
return VERR_NOT_FOUND;
}
/*
* Read the whole log buffer.
*/
uint8_t *pbLogBuf = (uint8_t *)RTMemAlloc(cbLogBuf);
if (!pbLogBuf)
{
Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: Failed to allocate %#x bytes for log buffer\n", cbLogBuf));
return VERR_NO_MEMORY;
}
DBGFADDRESS Addr;
rc = DBGFR3MemRead(pUVM, 0 /*idCpu*/, DBGFR3AddrFromFlat(pUVM, &Addr, GCPtrLogBuf), pbLogBuf, cbLogBuf);
if (RT_FAILURE(rc))
{
Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: Error reading %#x bytes of log buffer at %RGv: %Rrc\n",
cbLogBuf, Addr.FlatPtr, rc));
RTMemFree(pbLogBuf);
return VERR_NOT_FOUND;
}
/*
* Count the messages in the buffer while doing some basic validation.
*/
uint32_t const cbUsed = idxFirst == idxNext ? cbLogBuf /* could be empty... */
: idxFirst < idxNext ? idxNext - idxFirst : cbLogBuf - idxFirst + idxNext;
uint32_t cbLeft = cbUsed;
uint32_t offCur = idxFirst;
uint32_t cLogMsgs = 0;
while (cbLeft > 0)
{
PCLNXPRINTKHDR pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
if (!pHdr->cbTotal)
{
/* Wrap around packet, most likely... */
if (cbLogBuf - offCur >= cbLeft)
break;
offCur = 0;
pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
}
if (RT_UNLIKELY( pHdr->cbTotal > cbLogBuf - sizeof(*pHdr) - offCur
|| pHdr->cbTotal > cbLeft
|| (pHdr->cbTotal & (cbLogAlign - 1)) != 0
|| pHdr->cbTotal < (uint32_t)pHdr->cbText + (uint32_t)pHdr->cbDict + sizeof(*pHdr) ))
{
Log(("dbgDiggerLinuxIDmsg_QueryKernelLog: Invalid printk_log record at %#x: cbTotal=%#x cbText=%#x cbDict=%#x cbLogBuf=%#x cbLeft=%#x\n",
offCur, pHdr->cbTotal, pHdr->cbText, pHdr->cbDict, cbLogBuf, cbLeft));
rc = VERR_INVALID_STATE;
break;
}
if (pHdr->cbText > 0)
cLogMsgs++;
/* next */
offCur += pHdr->cbTotal;
cbLeft -= pHdr->cbTotal;
}
if (RT_FAILURE(rc))
{
RTMemFree(pbLogBuf);
return rc;
}
/*
* Copy the messages into the output buffer.
*/
offCur = idxFirst;
cbLeft = cbUsed;
/* Skip messages that the caller doesn't want. */
if (cMessages < cLogMsgs)
{
uint32_t cToSkip = cLogMsgs - cMessages;
while (cToSkip > 0)
{
PCLNXPRINTKHDR pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
if (!pHdr->cbTotal)
{
offCur = 0;
pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
}
if (pHdr->cbText > 0)
cToSkip--;
/* next */
offCur += pHdr->cbTotal;
cbLeft -= pHdr->cbTotal;
}
}
/* Now copy the messages. */
size_t offDst = 0;
while (cbLeft > 0)
{
PCLNXPRINTKHDR pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
if (!pHdr->cbTotal)
{
if (cbLogBuf - offCur >= cbLeft)
break;
offCur = 0;
pHdr = (PCLNXPRINTKHDR)&pbLogBuf[offCur];
}
if (pHdr->cbText > 0)
{
char *pchText = (char *)(pHdr + 1);
size_t cchText = RTStrNLen(pchText, pHdr->cbText);
if (offDst + cchText < cbBuf)
{
memcpy(&pszBuf[offDst], pHdr + 1, cchText);
pszBuf[offDst + cchText] = '\n';
}
else if (offDst < cbBuf)
memcpy(&pszBuf[offDst], pHdr + 1, cbBuf - offDst);
offDst += cchText + 1;
}
/* next */
offCur += pHdr->cbTotal;
cbLeft -= pHdr->cbTotal;
}
/* Done with the buffer. */
RTMemFree(pbLogBuf);
/* Make sure we've reserved a char for the terminator. */
if (!offDst)
offDst = 1;
/* Set return size value. */
if (pcbActual)
*pcbActual = offDst;
/*
* All VBox strings are UTF-8 and bad things may in theory happen if we
* pass bad UTF-8 to code which assumes it's all valid. So, we enforce
* UTF-8 upon the guest kernel messages here even if they (probably) have
* no defined code set in reality.
*/
if (offDst <= cbBuf)
{
pszBuf[offDst - 1] = '\0';
RTStrPurgeEncoding(pszBuf);
return VINF_SUCCESS;
}
if (cbBuf)
{
pszBuf[cbBuf - 1] = '\0';
RTStrPurgeEncoding(pszBuf);
}
return VERR_BUFFER_OVERFLOW;
}