diff options
Diffstat (limited to 'src/libutil/util.cc')
| -rw-r--r-- | src/libutil/util.cc | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/src/libutil/util.cc b/src/libutil/util.cc new file mode 100644 index 000000000..299a37f6c --- /dev/null +++ b/src/libutil/util.cc @@ -0,0 +1,318 @@ +#include <iostream> +#include <cerrno> +#include <cstdio> + +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> +#include <dirent.h> + +#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)) +{ +} + + +Path absPath(Path path, Path dir) +{ + if (path[0] != '/') { + if (dir == "") { + char buf[PATH_MAX]; + if (!getcwd(buf, sizeof(buf))) + throw SysError("cannot get cwd"); + dir = buf; + } + path = dir + "/" + path; + } + return canonPath(path); +} + + +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; +} + + +Path dirOf(const Path & path) +{ + unsigned int pos = path.rfind('/'); + if (pos == string::npos) + throw Error(format("invalid file name: %1%") % path); + return Path(path, 0, pos); +} + + +string baseNameOf(const Path & path) +{ + unsigned int pos = path.rfind('/'); + if (pos == string::npos) + throw Error(format("invalid file name %1% ") % path); + return string(path, pos + 1); +} + + +bool pathExists(const Path & path) +{ + int res; + struct stat st; + res = stat(path.c_str(), &st); + if (!res) return true; + if (errno != ENOENT) + throw SysError(format("getting status of %1%") % path); + return false; +} + + +void deletePath(const Path & path) +{ + printMsg(lvlVomit, format("deleting path `%1%'") % path); + + struct stat st; + if (lstat(path.c_str(), &st)) + throw SysError(format("getting attributes of path `%1%'") % path); + + if (S_ISDIR(st.st_mode)) { + Strings names; + + { + AutoCloseDir dir = opendir(path.c_str()); + + struct dirent * dirent; + while (errno = 0, dirent = readdir(dir)) { + string name = dirent->d_name; + if (name == "." || name == "..") continue; + names.push_back(name); + } + } /* scoped to ensure that dir is closed at this point */ + + /* 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++) + deletePath(path + "/" + *i); + } + + if (remove(path.c_str()) == -1) + throw SysError(format("cannot unlink `%1%'") % path); +} + + +void makePathReadOnly(const Path & path) +{ + 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)) { + AutoCloseDir dir = opendir(path.c_str()); + + struct dirent * dirent; + while (errno = 0, dirent = readdir(dir)) { + string name = dirent->d_name; + if (name == "." || name == "..") continue; + makePathReadOnly(path + "/" + name); + } + } +} + + +static Path tempName() +{ + static int counter = 0; + char * s = getenv("TMPDIR"); + Path tmpRoot = s ? canonPath(Path(s)) : "/tmp"; + return (format("%1%/nix-%2%-%3%") % tmpRoot % getpid() % counter++).str(); +} + + +Path createTempDir() +{ + while (1) { + Path tmpDir = tempName(); + if (mkdir(tmpDir.c_str(), 0777) == 0) return tmpDir; + if (errno != EEXIST) + throw SysError(format("creating directory `%1%'") % tmpDir); + } +} + + +Verbosity verbosity = lvlError; + +static int nestingLevel = 0; + + +Nest::Nest() +{ + nest = false; +} + + +Nest::~Nest() +{ + if (nest) nestingLevel--; +} + + +void Nest::open(Verbosity level, const format & f) +{ + if (level <= verbosity) { + printMsg_(level, f); + nest = true; + nestingLevel++; + } +} + + +void printMsg_(Verbosity level, const format & f) +{ + if (level > verbosity) return; + string spaces; + for (int i = 0; i < nestingLevel; i++) + spaces += "| "; + cerr << format("%1%%2%\n") % spaces % f.str(); +} + + +void readFull(int fd, unsigned char * buf, size_t count) +{ + while (count) { + ssize_t res = read(fd, (char *) buf, count); + if (res == -1) 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) { + ssize_t res = write(fd, (char *) buf, count); + if (res == -1) 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() +{ + if (fd != -1) close(fd); +} + +void AutoCloseFD::operator =(int fd) +{ + this->fd = fd; +} + +AutoCloseFD::operator int() +{ + return fd; +} + + +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; +} + |