lix-releng-staging/src/libutil/util.cc

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#include "config.h"
#include <iostream>
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#include <cerrno>
#include <cstdio>
#include <sstream>
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#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>
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#include <fcntl.h>
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#include "util.hh"
string thisSystem = SYSTEM;
Error::Error(const format & f)
{
err = f.str();
}
SysError::SysError(const format & f)
: Error(format("%1%: %2%") % f.str() % strerror(errno))
{
}
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string getEnv(const string & key, const string & def)
{
char * value = getenv(key.c_str());
return value ? string(value) : def;
}
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Path absPath(Path path, Path dir)
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{
if (path[0] != '/') {
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if (dir == "") {
char buf[PATH_MAX];
if (!getcwd(buf, sizeof(buf)))
throw SysError("cannot get cwd");
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dir = buf;
}
path = dir + "/" + path;
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}
return canonPath(path);
}
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Path canonPath(const Path & path)
{
string s;
if (path[0] != '/')
throw Error(format("not an absolute path: `%1%'") % path);
string::const_iterator i = path.begin(), end = path.end();
while (1) {
/* Skip slashes. */
while (i != end && *i == '/') i++;
if (i == end) break;
/* Ignore `.'. */
if (*i == '.' && (i + 1 == end || i[1] == '/'))
i++;
/* If `..', delete the last component. */
else if (*i == '.' && i + 1 < end && i[1] == '.' &&
(i + 2 == end || i[2] == '/'))
{
if (!s.empty()) s.erase(s.rfind('/'));
i += 2;
}
/* Normal component; copy it. */
else {
s += '/';
while (i != end && *i != '/') s += *i++;
}
}
return s.empty() ? "/" : s;
}
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Path dirOf(const Path & path)
{
unsigned int pos = path.rfind('/');
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if (pos == string::npos)
throw Error(format("invalid file name: %1%") % path);
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return Path(path, 0, pos);
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}
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string baseNameOf(const Path & path)
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{
unsigned int pos = path.rfind('/');
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if (pos == string::npos)
throw Error(format("invalid file name %1% ") % path);
return string(path, pos + 1);
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}
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bool pathExists(const Path & path)
{
int res;
struct stat st;
res = lstat(path.c_str(), &st);
if (!res) return true;
if (errno != ENOENT)
throw SysError(format("getting status of %1%") % path);
return false;
}
Path readLink(const Path & path)
{
struct stat st;
if (lstat(path.c_str(), &st))
throw SysError(format("getting status of `%1%'") % path);
if (!S_ISLNK(st.st_mode))
throw Error(format("`%1%' is not a symlink") % path);
char buf[st.st_size];
if (readlink(path.c_str(), buf, st.st_size) != st.st_size)
throw SysError(format("reading symbolic link `%1%'") % path);
return string(buf, st.st_size);
}
Strings readDirectory(const Path & path)
{
Strings names;
AutoCloseDir dir = opendir(path.c_str());
if (!dir) throw SysError(format("opening directory `%1%'") % path);
struct dirent * dirent;
while (errno = 0, dirent = readdir(dir)) { /* sic */
checkInterrupt();
string name = dirent->d_name;
if (name == "." || name == "..") continue;
names.push_back(name);
}
if (errno) throw SysError(format("reading directory `%1%'") % path);
return names;
}
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static void _deletePath(const Path & path)
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{
checkInterrupt();
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printMsg(lvlVomit, format("%1%") % path);
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struct stat st;
if (lstat(path.c_str(), &st))
throw SysError(format("getting attributes of path `%1%'") % path);
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if (S_ISDIR(st.st_mode)) {
Strings names = readDirectory(path);
/* Make the directory writable. */
if (!(st.st_mode & S_IWUSR)) {
if (chmod(path.c_str(), st.st_mode | S_IWUSR) == -1)
throw SysError(format("making `%1%' writable"));
}
for (Strings::iterator i = names.begin(); i != names.end(); ++i)
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_deletePath(path + "/" + *i);
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}
if (remove(path.c_str()) == -1)
throw SysError(format("cannot unlink `%1%'") % path);
}
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void deletePath(const Path & path)
{
startNest(nest, lvlDebug,
format("recursively deleting path `%1%'") % path);
_deletePath(path);
}
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void makePathReadOnly(const Path & path)
{
checkInterrupt();
struct stat st;
if (lstat(path.c_str(), &st))
throw SysError(format("getting attributes of path `%1%'") % path);
if (!S_ISLNK(st.st_mode) && (st.st_mode & S_IWUSR)) {
if (chmod(path.c_str(), st.st_mode & ~S_IWUSR) == -1)
throw SysError(format("making `%1%' read-only") % path);
}
if (S_ISDIR(st.st_mode)) {
Strings names = readDirectory(path);
for (Strings::iterator i = names.begin(); i != names.end(); ++i)
makePathReadOnly(path + "/" + *i);
}
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}
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static Path tempName()
{
static int counter = 0;
Path tmpRoot = canonPath(getEnv("TMPDIR", "/tmp"));
return (format("%1%/nix-%2%-%3%") % tmpRoot % getpid() % counter++).str();
}
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Path createTempDir()
{
while (1) {
checkInterrupt();
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Path tmpDir = tempName();
if (mkdir(tmpDir.c_str(), 0777) == 0) return tmpDir;
if (errno != EEXIST)
throw SysError(format("creating directory `%1%'") % tmpDir);
}
}
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void writeStringToFile(const Path & path, const string & s)
{
AutoCloseFD fd = open(path.c_str(),
O_CREAT | O_EXCL | O_WRONLY, 0666);
if (fd == -1)
throw SysError(format("creating file `%1%'") % path);
writeFull(fd, (unsigned char *) s.c_str(), s.size());
}
LogType logType = ltPretty;
Verbosity verbosity = lvlError;
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static int nestingLevel = 0;
Nest::Nest()
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{
nest = false;
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}
Nest::~Nest()
{
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close();
}
static string escVerbosity(Verbosity level)
{
int l = (int) level;
ostringstream st;
st << l;
return st.str();
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}
void Nest::open(Verbosity level, const format & f)
{
if (level <= verbosity) {
if (logType == ltEscapes)
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cerr << "\033[" << escVerbosity(level) << "p"
<< f.str() << "\n";
else
printMsg_(level, f);
nest = true;
nestingLevel++;
}
}
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void Nest::close()
{
if (nest) {
nestingLevel--;
if (logType == ltEscapes)
cerr << "\033[q";
nest = false;
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}
}
void printMsg_(Verbosity level, const format & f)
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{
checkInterrupt();
if (level > verbosity) return;
string prefix;
if (logType == ltPretty)
for (int i = 0; i < nestingLevel; i++)
prefix += "| ";
else if (logType == ltEscapes && level != lvlInfo)
prefix = "\033[" + escVerbosity(level) + "s";
cerr << format("%1%%2%\n") % prefix % f.str();
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}
void readFull(int fd, unsigned char * buf, size_t count)
{
while (count) {
checkInterrupt();
ssize_t res = read(fd, (char *) buf, count);
if (res == -1) {
if (errno == EINTR) continue;
throw SysError("reading from file");
}
if (res == 0) throw Error("unexpected end-of-file");
count -= res;
buf += res;
}
}
void writeFull(int fd, const unsigned char * buf, size_t count)
{
while (count) {
checkInterrupt();
ssize_t res = write(fd, (char *) buf, count);
if (res == -1) {
if (errno == EINTR) continue;
throw SysError("writing to file");
}
count -= res;
buf += res;
}
}
AutoDelete::AutoDelete(const string & p) : path(p)
{
del = true;
}
AutoDelete::~AutoDelete()
{
if (del) deletePath(path);
}
void AutoDelete::cancel()
{
del = false;
}
AutoCloseFD::AutoCloseFD()
{
fd = -1;
}
AutoCloseFD::AutoCloseFD(int fd)
{
this->fd = fd;
}
AutoCloseFD::~AutoCloseFD()
{
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try {
close();
} catch (Error & e) {
printMsg(lvlError, format("error (ignored): %1%") % e.msg());
}
}
void AutoCloseFD::operator =(int fd)
{
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if (this->fd != fd) close();
this->fd = fd;
}
AutoCloseFD::operator int()
{
return fd;
}
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void AutoCloseFD::close()
{
if (fd != -1) {
if (::close(fd) == -1)
/* This should never happen. */
throw SysError("closing file descriptor");
fd = -1;
}
}
bool AutoCloseFD::isOpen()
{
return fd != -1;
}
void Pipe::create()
{
int fds[2];
if (pipe(fds) != 0) throw SysError("creating pipe");
readSide = fds[0];
writeSide = fds[1];
}
AutoCloseDir::AutoCloseDir()
{
dir = 0;
}
AutoCloseDir::AutoCloseDir(DIR * dir)
{
this->dir = dir;
}
AutoCloseDir::~AutoCloseDir()
{
if (dir) closedir(dir);
}
void AutoCloseDir::operator =(DIR * dir)
{
this->dir = dir;
}
AutoCloseDir::operator DIR *()
{
return dir;
}
volatile sig_atomic_t _isInterrupted = 0;
void _interrupted()
{
/* Block user interrupts while an exception is being handled.
Throwing an exception while another exception is being handled
kills the program! */
if (!uncaught_exception()) {
_isInterrupted = 0;
throw Error("interrupted by the user");
}
}