1 files changed, 253 insertions, 0 deletions
diff --git a/src/libnix/util.cc b/src/libnix/util.cc
new file mode 100644
index 000000000000..c1d0fedea8aa
--- /dev/null
+++ b/src/libnix/util.cc
@@ -0,0 +1,253 @@
+#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)
+{
+    msg(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;
+
+        DIR * 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);
+        }
+
+        closedir(dir); /* !!! close on exception */
+
+	/* 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)) {
+        DIR * 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);
+        }
+
+        closedir(dir); /* !!! close on exception */
+    }
+}
+
+
+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(Verbosity level, const format & f)
+{
+    if (level > verbosity)
+        nest = false;
+    else {
+        msg(level, f);
+        nest = true;
+        nestingLevel++;
+    }
+}
+
+
+Nest::~Nest()
+{
+    if (nest) nestingLevel--;
+}
+
+
+void msg(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 debug(const format & f)
+{
+    msg(lvlDebug, f);
+}
+
+
+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;
+    }
+}