Sawyer::Optional<rose_addr_t>
MemoryMap::findAny(const AddressInterval &limits, const std::vector<uint8_t> &bytesToFind,
unsigned requiredPerms, unsigned prohibitedPerms) const
{
if (!limits || bytesToFind.empty())
return Sawyer::Nothing();
// Read a bunch of bytes at a time. If the buffer size is large then we'll have fewer read calls before finding a match,
// which is good if a match is unlikely. But if a match is likely, then it's better to use a smaller buffer so we don't
// ready more than necessary to find a match. We'll compromise by starting with a small buffer that grows up to some
// limit.
size_t nremaining = limits.size(); // bytes remaining to search (could be zero if limits is universe)
size_t bufsize = 8; // initial buffer size
uint8_t buffer[4096]; // full buffer
Sawyer::Optional<rose_addr_t> atVa = this->at(limits.least()).require(requiredPerms).prohibit(prohibitedPerms).next();
while (atVa && *atVa <= limits.greatest()) {
if (nremaining > 0) // zero implies entire address space
bufsize = std::min(bufsize, nremaining);
size_t nread = at(*atVa).limit(bufsize).require(requiredPerms).prohibit(prohibitedPerms).read(buffer).size();
assert(nread > 0); // because of the next() calls
for (size_t offset=0; offset<nread; ++offset) {
if (std::find(bytesToFind.begin(), bytesToFind.end(), buffer[offset]) != bytesToFind.end())
return *atVa + offset; // found
}
atVa = at(*atVa+nread).require(requiredPerms).prohibit(prohibitedPerms).next();
bufsize = std::min(2*bufsize, sizeof buffer); // use a larger buffer next time if possible
nremaining -= nread; // ok if nremaining is already zero
}
return Sawyer::Nothing();
}
size_t
MemoryMap::insertFile(const std::string &fileName, rose_addr_t startVa, bool writable, std::string segmentName) {
if (segmentName.empty())
segmentName = FileSystem::toString(boost::filesystem::path(fileName).filename());
Segment segment = Segment::fileInstance(fileName, READABLE | (writable?WRITABLE:0), segmentName);
AddressInterval fileInterval = AddressInterval::baseSize(startVa, segment.buffer()->size());
insert(fileInterval, segment);
return fileInterval.size();
}
void
MemoryMap::eraseZeros(size_t minsize)
{
if (isEmpty())
return;
unsigned permissions = READABLE | EXECUTABLE; // access permissions that must be present
AddressIntervalSet toRemove; // to save up intervals until we're done iterating
AddressInterval zeroInterval;
uint8_t buf[8192];
rose_addr_t va = hull().least();
while (AddressInterval accessed = atOrAfter(va).require(permissions).limit(sizeof buf).read(buf)) {
for (size_t offset=0; offset<accessed.size(); ++offset) {
if (0 == buf[offset]) {
if (zeroInterval.isEmpty()) {
zeroInterval = AddressInterval(accessed.least()+offset);
} else if (zeroInterval.greatest()+1 < offset) {
if (zeroInterval.size() >= minsize)
toRemove.insert(zeroInterval);
zeroInterval = AddressInterval(accessed.least()+offset);
} else {
zeroInterval = AddressInterval::hull(zeroInterval.least(), zeroInterval.greatest()+1);
}
} else if (!zeroInterval.isEmpty()) {
if (zeroInterval.size() >= minsize)
toRemove.insert(zeroInterval);
zeroInterval = AddressInterval();
}
}
if (accessed.greatest() == hull().greatest())
break; // prevent overflow in next statement
va += accessed.size();
}
if (zeroInterval.size() >= minsize)
toRemove.insert(zeroInterval);
BOOST_FOREACH (const AddressInterval &interval, toRemove.intervals())
erase(interval);
}
// FIXME[Robb P. Matzke 2014-10-09]: No idea how to do this in Microsoft Windows!
void
MemoryMap::insertProcess(const std::string &locatorString) {
#ifdef BOOST_WINDOWS // FIXME[Robb P. Matzke 2014-10-10]
throw std::runtime_error("MemoryMap::insertProcess is not available on Microsoft Windows");
#else
// Resources that need to be cleaned up on return or exception
struct T {
FILE *mapsFile; // file for /proc/xxx/maps
char *buf; // line read from /proc/xxx/maps
size_t bufsz; // bytes allocated for "buf"
int memFile; // file for /proc/xxx/mem
pid_t resumeProcess; // subordinate process to resume
T(): mapsFile(NULL), buf(NULL), bufsz(0), memFile(-1), resumeProcess(-1) {}
~T() {
if (mapsFile)
fclose(mapsFile);
if (buf)
free(buf);
if (memFile>=0)
close(memFile);
if (resumeProcess != -1)
ptrace(PTRACE_DETACH, resumeProcess, 0, 0);
}
} local;
// Parse the locator string.
bool doAttach = true;
const char *s = locatorString.c_str();
if (':'!=*s++)
throw insertProcessError(locatorString, "initial colon expected");
while (':'!=*s) {
if (boost::starts_with(s, "noattach")) {
doAttach = false;
s += strlen("noattach");
} else {
throw insertProcessError(locatorString, "unknown option beginning at ...\"" + std::string(s) + "\"");
}
if (','==*s)
++s;
}
if (':'!=*s++)
throw insertProcessError(locatorString, "second colon expected");
int pid = parseInteger(locatorString, s /*in,out*/, "process ID expected");
// We need to attach to the process with ptrace before we can read from its /proc/xxx/mem file. We'll have
// to detach if anything goes wrong or when we finish.
if (doAttach) {
if (-1 == ptrace(PTRACE_ATTACH, pid, 0, 0))
throw insertProcessError(locatorString, "cannot attach: " + std::string(strerror(errno)));
int wstat = 0;
if (-1 == waitpid(pid, &wstat, 0))
throw insertProcessError(locatorString, "cannot wait: " + std::string(strerror(errno)));
if (WIFEXITED(wstat))
throw insertProcessError(locatorString, "process exited before it could be read");
if (WIFSIGNALED(wstat))
throw insertProcessError(locatorString, "process died with " +
boost::to_lower_copy(std::string(strsignal(WTERMSIG(wstat)))) +
" before it could be read");
local.resumeProcess = pid;
ASSERT_require2(WIFSTOPPED(wstat) && WSTOPSIG(wstat)==SIGSTOP, "subordinate process did not stop");
}
// Prepare to read subordinate's memory
std::string mapsName = "/proc/" + StringUtility::numberToString(pid) + "/maps";
if (NULL==(local.mapsFile = fopen(mapsName.c_str(), "r")))
throw insertProcessError(locatorString, "cannot open " + mapsName + ": " + strerror(errno));
std::string memName = "/proc/" + StringUtility::numberToString(pid) + "/mem";
if (-1 == (local.memFile = open(memName.c_str(), O_RDONLY)))
throw insertProcessError(locatorString, "cannot open " + memName + ": " + strerror(errno));
// Read each line from the /proc/xxx/maps to figure out what memory is mapped in the subordinate process. The format for
// the part we're interested in is /^([0-9a-f]+)-([0-9a-f]+) ([-r][-w][-x])/ where $1 is the inclusive starting address, $2
// is the exclusive ending address, and $3 are the permissions.
int mapsFileLineNumber = 0;
while (rose_getline(&local.buf, &local.bufsz, local.mapsFile)>0) {
++mapsFileLineNumber;
// Begin address
char *s=local.buf, *rest=s;
errno = 0;
rose_addr_t begin = rose_strtoull(s, &rest, 16);
if (errno!=0 || rest==s || '-'!=*rest) {
throw insertProcessError(locatorString, mapsName + " syntax error for beginning address at line " +
StringUtility::numberToString(mapsFileLineNumber) + ": " + local.buf);
}
// End address
s = rest+1;
rose_addr_t end = rose_strtoull(s, &rest, 16);
if (errno!=0 || rest==s || ' '!=*rest) {
throw insertProcessError(locatorString, mapsName + " syntax error for ending address at line " +
StringUtility::numberToString(mapsFileLineNumber) + ": " + local.buf);
}
if (begin >= end) {
throw insertProcessError(locatorString, mapsName + " invalid address range at line " +
StringUtility::numberToString(mapsFileLineNumber) + ": " + local.buf);
}
// Access permissions
s = ++rest;
if ((s[0]!='r' && s[0]!='-') || (s[1]!='w' && s[1]!='-') || (s[2]!='x' && s[2]!='-')) {
throw insertProcessError(locatorString, mapsName + " invalid access permissions at line " +
StringUtility::numberToString(mapsFileLineNumber) + ": " + local.buf);
}
unsigned accessibility = ('r'==s[0] ? READABLE : 0) | ('w'==s[1] ? WRITABLE : 0) | ('x'==s[2] ? EXECUTABLE : 0);
// Skip over unused fields
for (size_t nSpaces=0; nSpaces<4 && *s; ++s) {
if (isspace(*s))
++nSpaces;
}
while (isspace(*s)) ++s;
// Segment name according to the kernel
std::string kernelSegmentName;
while (*s && !isspace(*s))
kernelSegmentName += *s++;
// Create memory segment, but don't insert it until after we read all the data
std::string segmentName = "proc:" + StringUtility::numberToString(pid);
AddressInterval segmentInterval = AddressInterval::baseSize(begin, end-begin);
Segment segment = Segment::anonymousInstance(segmentInterval.size(), accessibility,
segmentName + "(" + kernelSegmentName + ")");
// Copy data from the subordinate process into our memory segment
if (-1 == lseek(local.memFile, begin, SEEK_SET))
throw insertProcessError(locatorString, memName + " seek failed: " + strerror(errno));
size_t nRemain = segmentInterval.size();
rose_addr_t segmentBufferOffset = 0;
while (nRemain > 0) {
uint8_t chunkBuf[8192];
size_t chunkSize = std::min(nRemain, sizeof chunkBuf);
ssize_t nRead = ::read(local.memFile, chunkBuf, chunkSize);
if (-1==nRead) {
if (EINTR==errno)
continue;
//mlog[WARN] <<strerror(errno) <<" during read from " <<memName <<" for segment " <<kernelSegmentName
// <<" at " <<segmentInterval <<"\n";
segmentName += "[" + boost::to_lower_copy(std::string(strerror(errno))) + "]";
break;
} else if (0==nRead) {
//mlog[WARN] <<"short read from " <<memName <<" for segment " <<kernelSegmentName <<" at " <<segmentInterval <<"\n";
segmentName += "[short read]";
break;
}
rose_addr_t nWrite = segment.buffer()->write(chunkBuf, segmentBufferOffset, nRead);
ASSERT_always_require(nWrite == (rose_addr_t)nRead);
nRemain -= chunkSize;
segmentBufferOffset += chunkSize;
}
if (nRemain > 0) {
// If a read failed, map only what we could read
segmentInterval = AddressInterval::baseSize(segmentInterval.least(), segmentInterval.size()-nRemain);
}
// Insert segment into memory map
if (!segmentInterval.isEmpty())
insert(segmentInterval, segment);
}
#endif
}
// Insert file from a locator string of the form:
// :[VA][+VSIZE][=PERMS]:[OFFSET][+FSIZE]:FILENAME
AddressInterval
MemoryMap::insertFile(const std::string &locatorString) {
//--------------------------------------
// Parse the parts of the locator string
//--------------------------------------
// Leading colon
const char *s = locatorString.c_str();
if (':'!=*s++)
throw insertFileError(locatorString, "not a locator string");
// Virtual address
Sawyer::Optional<rose_addr_t> optionalVa;
if (isdigit(*s))
optionalVa = parseInteger(locatorString, s /*in,out*/, "virtual address expected");
// Virtual size
Sawyer::Optional<size_t> optionalVSize;
if ('+'==*s) {
++s;
optionalVSize = parseInteger(locatorString, s /*in,out*/, "virtual size expected");
}
// Virtual accessibility
Sawyer::Optional<unsigned> optionalAccess;
if ('='==*s) {
++s;
unsigned a = 0;
if ('r'==*s) {
++s;
a |= READABLE;
}
if ('w'==*s) {
++s;
a |= WRITABLE;
}
if ('x'==*s) {
++s;
a |= EXECUTABLE;
}
optionalAccess = a;
}
// Second colon
if (':'!=*s) {
if (*s && optionalAccess)
throw insertFileError(locatorString, "invalid access spec");
throw insertFileError(locatorString, "syntax error before second colon");
}
++s;
// File offset
Sawyer::Optional<size_t> optionalOffset;
if (isdigit(*s))
optionalOffset = parseInteger(locatorString, s /*in,out*/, "file offset expected");
// File size
Sawyer::Optional<size_t> optionalFSize;
if ('+'==*s) {
++s;
optionalFSize = parseInteger(locatorString, s /*in,out*/, "file size expected");
}
// Third colon
if (':'!=*s)
throw insertFileError(locatorString, "syntax error before third colon");
++s;
// File name
if (!*s)
throw insertFileError(locatorString, "file name expected after third colon");
std::string fileName = s;
if (fileName.size()!=strlen(fileName.c_str()))
throw insertFileError(locatorString, "invalid file name");
std::string segmentName = FileSystem::toString(boost::filesystem::path(fileName).filename());
//--------------------------------
// Open the file and read the data
//--------------------------------
// Open the file and seek to the start of data
std::ifstream file(fileName.c_str());
if (!file.good())
throw std::runtime_error("MemoryMap::insertFile: cannot open file \""+StringUtility::cEscape(fileName)+"\"");
if (optionalOffset)
file.seekg(*optionalOffset);
if (!file.good())
throw std::runtime_error("MemoryMap::insertFile: cannot seek in file \""+StringUtility::cEscape(fileName)+"\"");
// If no file size was specified then try to get one, or delay getting one until later. On POSIX systems we can use stat
// to get the file size, which is useful because infinite devices (like /dev/zero) will return zero. Otherwise we'll get
// the file size by trying to read from the file.
#if !defined(BOOST_WINDOWS) // not targeting Windows; i.e., not Microsoft C++ and not MinGW
if (!optionalFSize) {
struct stat sb;
if (0==stat(fileName.c_str(), &sb))
optionalFSize = sb.st_size;
}
#endif
// Limit the file size according to the virtual size. We never need to read more than what would be mapped.
if (optionalVSize) {
if (optionalFSize) {
optionalFSize = std::min(*optionalFSize, *optionalVSize);
} else {
optionalFSize = optionalVSize;
}
}
// Read the file data. If we know the file size then we can allocate a buffer and read it all in one shot, otherwise we'll
// have to read a little at a time (only happens on Windows due to stat call above).
uint8_t *data = NULL; // data read from the file
size_t nRead = 0; // bytes of data actually allocated, read, and initialized in "data"
if (optionalFSize) {
// This is reasonably fast and not too bad on memory
if (0 != *optionalFSize) {
data = new uint8_t[*optionalFSize];
file.read((char*)data, *optionalFSize);
nRead = file.gcount();
if (nRead != *optionalFSize)
throw std::runtime_error("MemoryMap::insertFile: short read from \""+StringUtility::cEscape(fileName)+"\"");
}
} else {
while (file.good()) {
uint8_t page[4096];
file.read((char*)page, sizeof page);
size_t n = file.gcount();
uint8_t *tmp = new uint8_t[nRead + n];
memcpy(tmp, data, nRead);
memcpy(tmp+nRead, page, n);
delete[] data;
data = tmp;
nRead += n;
}
optionalFSize = nRead;
}
// Choose virtual size
if (!optionalVSize) {
ASSERT_require(optionalFSize);
optionalVSize = optionalFSize;
}
// Choose accessibility
if (!optionalAccess) {
#ifdef BOOST_WINDOWS
optionalAccess = READABLE | WRITABLE;
#else
unsigned a = 0;
if (0==::access(fileName.c_str(), R_OK))
a |= READABLE;
if (0==::access(fileName.c_str(), W_OK))
a |= WRITABLE;
if (0==::access(fileName.c_str(), X_OK))
a |= EXECUTABLE;
optionalAccess = a;
#endif
}
// Find a place to map the file.
if (!optionalVa) {
ASSERT_require(optionalVSize);
optionalVa = findFreeSpace(*optionalVSize);
}
// Adjust the memory map
ASSERT_require(optionalVa);
ASSERT_require(optionalVSize);
ASSERT_require(optionalAccess);
ASSERT_require(nRead <= *optionalVSize);
if (0 == *optionalVSize)
return AddressInterval(); // empty
AddressInterval interval = AddressInterval::baseSize(*optionalVa, *optionalVSize);
insert(interval, Segment::anonymousInstance(interval.size(), *optionalAccess, segmentName));
size_t nCopied = at(interval.least()).limit(nRead).write(data).size();
ASSERT_always_require(nRead==nCopied); // better work since we just created the segment!
return interval;
}
