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don't allocate large buffers on the stack

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This commit is contained in:
Will Dietz 2018-03-01 15:00:58 -06:00
parent 3748a0ca1e
commit c89a3d5368
5 changed files with 30 additions and 29 deletions
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23
src/libutil/util.cc
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@ -229,16 +229,17 @@ bool pathExists(const Path & path)
Path readLink(const Path & path)
{
checkInterrupt();
std::vector<char> buf;
for (ssize_t bufSize = PATH_MAX/4; true; bufSize += bufSize/2) {
char buf[bufSize];
ssize_t rlSize = readlink(path.c_str(), buf, bufSize);
buf.resize(bufSize);
ssize_t rlSize = readlink(path.c_str(), buf.data(), bufSize);
if (rlSize == -1)
if (errno == EINVAL)
throw Error("'%1%' is not a symlink", path);
else
throw SysError("reading symbolic link '%1%'", path);
else if (rlSize < bufSize)
return string(buf, rlSize);
return string(buf.data(), rlSize);
}
}
@ -293,10 +294,10 @@ string readFile(int fd)
if (fstat(fd, &st) == -1)
throw SysError("statting file");
auto buf = std::make_unique<unsigned char[]>(st.st_size);
readFull(fd, buf.get(), st.st_size);
std::vector<unsigned char> buf(st.st_size);
readFull(fd, buf.data(), st.st_size);
return string((char *) buf.get(), st.st_size);
return string((char *) buf.data(), st.st_size);
}
@ -438,10 +439,10 @@ Path createTempDir(const Path & tmpRoot, const Path & prefix,
static Lazy<Path> getHome2([]() {
Path homeDir = getEnv("HOME");
if (homeDir.empty()) {
char buf[16384];
std::vector<char> buf(16384);
struct passwd pwbuf;
struct passwd * pw;
if (getpwuid_r(getuid(), &pwbuf, buf, sizeof(buf), &pw) != 0
if (getpwuid_r(getuid(), &pwbuf, buf.data(), buf.size(), &pw) != 0
|| !pw || !pw->pw_dir || !pw->pw_dir[0])
throw Error("cannot determine user's home directory");
homeDir = pw->pw_dir;
@ -569,16 +570,16 @@ void writeFull(int fd, const string & s, bool allowInterrupts)
string drainFD(int fd)
{
string result;
unsigned char buffer[4096];
std::vector<unsigned char> buffer(4096);
while (1) {
checkInterrupt();
ssize_t rd = read(fd, buffer, sizeof buffer);
ssize_t rd = read(fd, buffer.data(), buffer.size());
if (rd == -1) {
if (errno != EINTR)
throw SysError("reading from file");
}
else if (rd == 0) break;
else result.append((char *) buffer, rd);
else result.append((char *) buffer.data(), rd);
}
return result;
}