forked from lix-project/lix
630ae0c9d7
get rid of GC roots. Nix-build places a symlink `result' in the current directory. Previously, removing that symlink would not remove the store path being linked to as a GC root. Now, the GC root created by nix-build is actually a symlink in `/nix/var/nix/gcroots/auto' to `result'. So if that symlink is removed the GC root automatically becomes invalid (since it can no longer be resolved). The root itself is not automatically removed - the garbage collector should delete dangling roots.
653 lines
13 KiB
C++
653 lines
13 KiB
C++
#include "config.h"
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#include <iostream>
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#include <cerrno>
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#include <cstdio>
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#include <sstream>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <dirent.h>
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#include <fcntl.h>
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#include <signal.h>
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#include "util.hh"
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string thisSystem = SYSTEM;
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Error::Error(const format & f)
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{
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err = f.str();
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}
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SysError::SysError(const format & f)
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: Error(format("%1%: %2%") % f.str() % strerror(errno))
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{
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}
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string getEnv(const string & key, const string & def)
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{
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char * value = getenv(key.c_str());
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return value ? string(value) : def;
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}
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Path absPath(Path path, Path dir)
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{
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if (path[0] != '/') {
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if (dir == "") {
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char buf[PATH_MAX];
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if (!getcwd(buf, sizeof(buf)))
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throw SysError("cannot get cwd");
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dir = buf;
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}
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path = dir + "/" + path;
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}
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return canonPath(path);
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}
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Path canonPath(const Path & path)
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{
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string s;
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if (path[0] != '/')
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throw Error(format("not an absolute path: `%1%'") % path);
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string::const_iterator i = path.begin(), end = path.end();
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while (1) {
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/* Skip slashes. */
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while (i != end && *i == '/') i++;
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if (i == end) break;
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/* Ignore `.'. */
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if (*i == '.' && (i + 1 == end || i[1] == '/'))
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i++;
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/* If `..', delete the last component. */
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else if (*i == '.' && i + 1 < end && i[1] == '.' &&
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(i + 2 == end || i[2] == '/'))
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{
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if (!s.empty()) s.erase(s.rfind('/'));
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i += 2;
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}
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/* Normal component; copy it. */
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else {
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s += '/';
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while (i != end && *i != '/') s += *i++;
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}
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}
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return s.empty() ? "/" : s;
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}
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Path dirOf(const Path & path)
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{
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unsigned int pos = path.rfind('/');
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if (pos == string::npos)
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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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{
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unsigned int pos = path.rfind('/');
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if (pos == string::npos)
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throw Error(format("invalid file name %1% ") % path);
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return string(path, pos + 1);
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}
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bool pathExists(const Path & path)
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{
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int res;
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struct stat st;
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res = lstat(path.c_str(), &st);
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if (!res) return true;
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if (errno != ENOENT && errno != ENOTDIR)
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throw SysError(format("getting status of %1%") % path);
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return false;
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}
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Path readLink(const Path & path)
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{
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struct stat st;
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if (lstat(path.c_str(), &st))
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throw SysError(format("getting status of `%1%'") % path);
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if (!S_ISLNK(st.st_mode))
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throw Error(format("`%1%' is not a symlink") % path);
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char buf[st.st_size];
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if (readlink(path.c_str(), buf, st.st_size) != st.st_size)
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throw SysError(format("reading symbolic link `%1%'") % path);
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return string(buf, st.st_size);
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}
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bool isLink(const Path & path)
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{
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struct stat st;
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if (lstat(path.c_str(), &st))
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throw SysError(format("getting status of `%1%'") % path);
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return S_ISLNK(st.st_mode);
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}
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Strings readDirectory(const Path & path)
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{
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Strings names;
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AutoCloseDir dir = opendir(path.c_str());
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if (!dir) throw SysError(format("opening directory `%1%'") % path);
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struct dirent * dirent;
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while (errno = 0, dirent = readdir(dir)) { /* sic */
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checkInterrupt();
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string name = dirent->d_name;
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if (name == "." || name == "..") continue;
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names.push_back(name);
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}
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if (errno) throw SysError(format("reading directory `%1%'") % path);
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return names;
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}
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static void _deletePath(const Path & path)
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{
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checkInterrupt();
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printMsg(lvlVomit, format("%1%") % path);
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struct stat st;
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if (lstat(path.c_str(), &st))
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throw SysError(format("getting attributes of path `%1%'") % path);
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if (S_ISDIR(st.st_mode)) {
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Strings names = readDirectory(path);
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/* Make the directory writable. */
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if (!(st.st_mode & S_IWUSR)) {
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if (chmod(path.c_str(), st.st_mode | S_IWUSR) == -1)
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throw SysError(format("making `%1%' writable") % path);
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}
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for (Strings::iterator i = names.begin(); i != names.end(); ++i)
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_deletePath(path + "/" + *i);
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}
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if (remove(path.c_str()) == -1)
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throw SysError(format("cannot unlink `%1%'") % path);
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}
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void deletePath(const Path & path)
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{
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startNest(nest, lvlDebug,
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format("recursively deleting path `%1%'") % path);
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_deletePath(path);
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}
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void makePathReadOnly(const Path & path)
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{
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checkInterrupt();
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struct stat st;
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if (lstat(path.c_str(), &st))
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throw SysError(format("getting attributes of path `%1%'") % path);
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if (!S_ISLNK(st.st_mode) && (st.st_mode & S_IWUSR)) {
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if (chmod(path.c_str(), st.st_mode & ~S_IWUSR) == -1)
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throw SysError(format("making `%1%' read-only") % path);
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}
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if (S_ISDIR(st.st_mode)) {
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Strings names = readDirectory(path);
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for (Strings::iterator i = names.begin(); i != names.end(); ++i)
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makePathReadOnly(path + "/" + *i);
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}
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}
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static Path tempName()
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{
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static int counter = 0;
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Path tmpRoot = canonPath(getEnv("TMPDIR", "/tmp"));
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return (format("%1%/nix-%2%-%3%") % tmpRoot % getpid() % counter++).str();
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}
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Path createTempDir()
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{
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while (1) {
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checkInterrupt();
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Path tmpDir = tempName();
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if (mkdir(tmpDir.c_str(), 0777) == 0) return tmpDir;
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if (errno != EEXIST)
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throw SysError(format("creating directory `%1%'") % tmpDir);
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}
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}
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void writeStringToFile(const Path & path, const string & s)
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{
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AutoCloseFD fd(open(path.c_str(),
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O_CREAT | O_EXCL | O_WRONLY, 0666));
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if (fd == -1)
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throw SysError(format("creating file `%1%'") % path);
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writeFull(fd, (unsigned char *) s.c_str(), s.size());
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}
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LogType logType = ltPretty;
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Verbosity verbosity = lvlInfo;
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static int nestingLevel = 0;
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Nest::Nest()
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{
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nest = false;
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}
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Nest::~Nest()
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{
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close();
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}
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static string escVerbosity(Verbosity level)
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{
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int l = (int) level;
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ostringstream st;
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st << l;
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return st.str();
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}
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void Nest::open(Verbosity level, const format & f)
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{
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if (level <= verbosity) {
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if (logType == ltEscapes)
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cerr << "\033[" << escVerbosity(level) << "p"
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<< f.str() << "\n";
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else
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printMsg_(level, f);
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nest = true;
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nestingLevel++;
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}
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}
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void Nest::close()
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{
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if (nest) {
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nestingLevel--;
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if (logType == ltEscapes)
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cerr << "\033[q";
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nest = false;
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}
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}
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void printMsg_(Verbosity level, const format & f)
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{
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checkInterrupt();
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if (level > verbosity) return;
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string prefix;
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if (logType == ltPretty)
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for (int i = 0; i < nestingLevel; i++)
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prefix += "| ";
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else if (logType == ltEscapes && level != lvlInfo)
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prefix = "\033[" + escVerbosity(level) + "s";
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cerr << format("%1%%2%\n") % prefix % f.str();
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}
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void readFull(int fd, unsigned char * buf, size_t count)
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{
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while (count) {
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checkInterrupt();
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ssize_t res = read(fd, (char *) buf, count);
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if (res == -1) {
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if (errno == EINTR) continue;
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throw SysError("reading from file");
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}
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if (res == 0) throw Error("unexpected end-of-file");
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count -= res;
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buf += res;
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}
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}
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void writeFull(int fd, const unsigned char * buf, size_t count)
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{
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while (count) {
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checkInterrupt();
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ssize_t res = write(fd, (char *) buf, count);
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if (res == -1) {
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if (errno == EINTR) continue;
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throw SysError("writing to file");
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}
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count -= res;
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buf += res;
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}
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}
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//////////////////////////////////////////////////////////////////////
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AutoDelete::AutoDelete(const string & p) : path(p)
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{
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del = true;
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}
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AutoDelete::~AutoDelete()
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{
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if (del) deletePath(path);
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}
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void AutoDelete::cancel()
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{
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del = false;
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}
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//////////////////////////////////////////////////////////////////////
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AutoCloseFD::AutoCloseFD()
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{
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fd = -1;
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}
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AutoCloseFD::AutoCloseFD(int fd)
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{
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this->fd = fd;
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}
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AutoCloseFD::AutoCloseFD(const AutoCloseFD & fd)
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{
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abort();
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}
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AutoCloseFD::~AutoCloseFD()
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{
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try {
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close();
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} catch (Error & e) {
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printMsg(lvlError, format("error (ignored): %1%") % e.msg());
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}
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}
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void AutoCloseFD::operator =(int fd)
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{
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if (this->fd != fd) close();
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this->fd = fd;
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}
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AutoCloseFD::operator int() const
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{
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return fd;
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}
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void AutoCloseFD::close()
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{
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if (fd != -1) {
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if (::close(fd) == -1)
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/* This should never happen. */
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throw SysError("closing file descriptor");
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fd = -1;
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}
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}
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bool AutoCloseFD::isOpen()
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{
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return fd != -1;
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}
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/* Pass responsibility for closing this fd to the caller. */
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int AutoCloseFD::borrow()
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{
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int oldFD = fd;
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fd = -1;
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return oldFD;
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}
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void Pipe::create()
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{
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int fds[2];
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if (pipe(fds) != 0) throw SysError("creating pipe");
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readSide = fds[0];
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writeSide = fds[1];
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}
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//////////////////////////////////////////////////////////////////////
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AutoCloseDir::AutoCloseDir()
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{
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dir = 0;
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}
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AutoCloseDir::AutoCloseDir(DIR * dir)
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{
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this->dir = dir;
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}
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AutoCloseDir::~AutoCloseDir()
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{
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if (dir) closedir(dir);
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}
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void AutoCloseDir::operator =(DIR * dir)
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{
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this->dir = dir;
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}
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AutoCloseDir::operator DIR *()
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{
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return dir;
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}
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//////////////////////////////////////////////////////////////////////
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Pid::Pid()
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{
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pid = -1;
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separatePG = false;
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}
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Pid::~Pid()
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{
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kill();
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}
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void Pid::operator =(pid_t pid)
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{
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if (this->pid != pid) kill();
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this->pid = pid;
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}
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Pid::operator pid_t()
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{
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return pid;
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}
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void Pid::kill()
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{
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if (pid == -1) return;
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printMsg(lvlError, format("killing process %1%") % pid);
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/* Send a KILL signal to the child. If it has its own process
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group, send the signal to every process in the child process
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group (which hopefully includes *all* its children). */
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if (::kill(separatePG ? -pid : pid, SIGKILL) != 0)
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printMsg(lvlError, (SysError(format("killing process %1%") % pid).msg()));
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/* Wait until the child dies, disregarding the exit status. */
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int status;
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while (waitpid(pid, &status, 0) == -1)
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if (errno != EINTR) printMsg(lvlError,
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(SysError(format("waiting for process %1%") % pid).msg()));
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pid = -1;
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}
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int Pid::wait(bool block)
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{
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while (1) {
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int status;
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int res = waitpid(pid, &status, block ? 0 : WNOHANG);
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if (res == pid) {
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pid = -1;
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return status;
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}
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if (res == 0 && !block) return -1;
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if (errno != EINTR)
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throw SysError("cannot get child exit status");
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}
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}
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void Pid::setSeparatePG(bool separatePG)
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{
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this->separatePG = separatePG;
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}
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//////////////////////////////////////////////////////////////////////
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volatile sig_atomic_t _isInterrupted = 0;
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void _interrupted()
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{
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/* Block user interrupts while an exception is being handled.
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Throwing an exception while another exception is being handled
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kills the program! */
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if (!uncaught_exception()) {
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_isInterrupted = 0;
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throw Error("interrupted by the user");
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}
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}
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//////////////////////////////////////////////////////////////////////
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string packStrings(const Strings & strings)
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{
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string d;
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for (Strings::const_iterator i = strings.begin();
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i != strings.end(); ++i)
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{
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unsigned int len = i->size();
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d += len & 0xff;
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d += (len >> 8) & 0xff;
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d += (len >> 16) & 0xff;
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d += (len >> 24) & 0xff;
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d += *i;
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}
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return d;
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}
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Strings unpackStrings(const string & s)
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{
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Strings strings;
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string::const_iterator i = s.begin();
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while (i != s.end()) {
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if (i + 4 > s.end())
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throw Error(format("short db entry: `%1%'") % s);
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unsigned int len;
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len = (unsigned char) *i++;
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len |= ((unsigned char) *i++) << 8;
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len |= ((unsigned char) *i++) << 16;
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len |= ((unsigned char) *i++) << 24;
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if (len == 0xffffffff) return strings; /* explicit end-of-list */
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if (i + len > s.end())
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throw Error(format("short db entry: `%1%'") % s);
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strings.push_back(string(i, i + len));
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i += len;
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}
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|
|
|
return strings;
|
|
}
|
|
|
|
|
|
string statusToString(int status)
|
|
{
|
|
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
|
|
if (WIFEXITED(status))
|
|
return (format("failed with exit code %1%") % WEXITSTATUS(status)).str();
|
|
else if (WIFSIGNALED(status))
|
|
return (format("failed due to signal %1%") % WTERMSIG(status)).str();
|
|
else
|
|
return "died abnormally";
|
|
} else return "succeeded";
|
|
}
|
|
|
|
|
|
bool statusOk(int status)
|
|
{
|
|
return WIFEXITED(status) && WEXITSTATUS(status) == 0;
|
|
}
|
|
|
|
|
|
bool string2Int(const string & s, int & n)
|
|
{
|
|
istringstream str(s);
|
|
str >> n;
|
|
return str && str.eof();
|
|
}
|