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# Utils.h

    00001 /*
    00002  *  Phusion Passenger - http://www.modrails.com/
    00003  *  Copyright (c) 2010 Phusion
    00004  *
    00005  *  "Phusion Passenger" is a trademark of Hongli Lai & Ninh Bui.
    00006  *
    00007  *  Permission is hereby granted, free of charge, to any person obtaining a copy
    00008  *  of this software and associated documentation files (the "Software"), to deal
    00009  *  in the Software without restriction, including without limitation the rights
    00010  *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    00011  *  copies of the Software, and to permit persons to whom the Software is
    00012  *  furnished to do so, subject to the following conditions:
    00013  *
    00014  *  The above copyright notice and this permission notice shall be included in
    00015  *  all copies or substantial portions of the Software.
    00016  *
    00017  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    00018  *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    00019  *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    00020  *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    00021  *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    00022  *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    00023  *  THE SOFTWARE.
    00024  */
    00025 #ifndef _PASSENGER_UTILS_H_
    00026 #define _PASSENGER_UTILS_H_
    00027
    00028 #include <boost/shared_ptr.hpp>
    00029 #include <sys/types.h>
    00030 #include <sys/stat.h>
    00031 #include <string>
    00032 #include <vector>
    00033 #include <utility>
    00034 #include <sstream>
    00035 #include <cstdio>
    00036 #include <climits>
    00037 #include <cstdlib>
    00038 #include <cstring>
    00039 #include <errno.h>
    00040 #include <unistd.h>
    00041 #include "StaticString.h"
    00042 #include "Exceptions.h"
    00043
    00044 namespace Passenger {
    00045
    00046 using namespace std;
    00047 using namespace boost;
    00048
    00049 static const uid_t USER_NOT_GIVEN = (uid_t) -1;
    00050 static const gid_t GROUP_NOT_GIVEN = (gid_t) -1;
    00051
    00052 typedef struct CachedFileStat CachedFileStat;
    00053 class ResourceLocator;
    00054
    00055 /** Enumeration which indicates what kind of file a file is. */
    00056 typedef enum {
    00057         /** The file doesn't exist. */
    00058         FT_NONEXISTANT,
    00059         /** A regular file or a symlink to a regular file. */
    00060         FT_REGULAR,
    00061         /** A directory. */
    00062         FT_DIRECTORY,
    00063         /** Something else, e.g. a pipe or a socket. */
    00064         FT_OTHER
    00065 } FileType;
    00066
    00067 /**
    00068  * Convenience shortcut for creating a <tt>shared_ptr</tt>.
    00069  * Instead of:
    00070  * @code
    00071  *    shared_ptr<Foo> foo;
    00072  *    ...
    00073  *    foo = shared_ptr<Foo>(new Foo());
    00074  * @endcode
    00075  * one can write:
    00076  * @code
    00077  *    shared_ptr<Foo> foo;
    00078  *    ...
    00079  *    foo = ptr(new Foo());
    00080  * @endcode
    00081  *
    00082  * @param pointer The item to put in the shared_ptr object.
    00083  * @ingroup Support
    00084  */
    00085 template<typename T> shared_ptr<T>
    00086 ptr(T *pointer) {
    00087         return shared_ptr<T>(pointer);
    00088 }
    00089
    00090 /**
    00091  * Check whether the specified file exists.
    00092  *
    00093  * @param filename The filename to check.
    00094  * @param cstat A CachedFileStat object, if you want to use cached statting.
    00095  * @param throttleRate A throttle rate for cstat. Only applicable if cstat is not NULL.
    00096  * @return Whether the file exists.
    00097  * @throws FileSystemException Unable to check because of a filesystem error.
    00098  * @throws TimeRetrievalException
    00099  * @throws boost::thread_interrupted
    00100  * @ingroup Support
    00101  */
    00102 bool fileExists(const StaticString &filename, CachedFileStat *cstat = 0,
    00103                 unsigned int throttleRate = 0);
    00104
    00105 /**
    00106  * Check whether 'filename' exists and what kind of file it is.
    00107  *
    00108  * @param filename The filename to check.
    00109  * @param mstat A CachedFileStat object, if you want to use cached statting.
    00110  * @param throttleRate A throttle rate for cstat. Only applicable if cstat is not NULL.
    00111  * @return The file type.
    00112  * @throws FileSystemException Unable to check because of a filesystem error.
    00113  * @throws TimeRetrievalException
    00114  * @throws boost::thread_interrupted
    00115  * @ingroup Support
    00116  */
    00117 FileType getFileType(const StaticString &filename, CachedFileStat *cstat = 0,
    00118                      unsigned int throttleRate = 0);
    00119
    00120 /**
    00121  * Create the given file with the given contents, permissions and ownership.
    00122  * This function does not leave behind junk files: if the ownership cannot be set
    00123  * or if not all data can be written then then the file will be deleted.
    00124  *
    00125  * @param filename The file to create.
    00126  * @param contents The contents to write to the file.
    00127  * @param permissions The desired file permissions.
    00128  * @param owner The desired file owner. Specify USER_NOT_GIVEN if you want to use the current
    00129  *              process's owner as the file owner.
    00130  * @param group The desired file group. Specify GROUP_NOT_GIVEN if you want to use the current
    00131  *              process's group as the file group.
    00132  * @param overwrite Whether to overwrite the file if it exists. If set to false
    00133  *                  and the file exists then nothing will happen.
    00134  * @throws FileSystemException Something went wrong.
    00135  * @ingroup Support
    00136  */
    00137 void createFile(const string &filename, const StaticString &contents,
    00138                 mode_t permissions = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH,
    00139                 uid_t owner = USER_NOT_GIVEN, gid_t group = GROUP_NOT_GIVEN,
    00140                 bool overwrite = true);
    00141
    00142 /**
    00143  * Returns a canonical version of the specified path. All symbolic links
    00144  * and relative path elements are resolved.
    00145  *
    00146  * @throws FileSystemException Something went wrong.
    00147  * @ingroup Support
    00148  */
    00149 string canonicalizePath(const string &path);
    00150
    00151 /**
    00152  * If <em>path</em> refers to a symlink, then this function resolves the
    00153  * symlink for 1 level. That is, if the symlink points to another symlink,
    00154  * then the other symlink will not be resolved. The resolved path is returned.
    00155  *
    00156  * If the symlink doesn't point to an absolute path, then this function will
    00157  * prepend <em>path</em>'s directory to the result.
    00158  *
    00159  * If <em>path</em> doesn't refer to a symlink then this method will return
    00160  * <em>path</em>.
    00161  *
    00162  * @throws FileSystemException Something went wrong.
    00163  * @ingroup Support
    00164  */
    00165 string resolveSymlink(const string &path);
    00166
    00167 /**
    00168  * Given a path, extracts its directory name.
    00169  *
    00170  * @ingroup Support
    00171  */
    00172 string extractDirName(const StaticString &path);
    00173
    00174 /**
    00175  * Given a path, extracts its base name.
    00176  *
    00177  * @ingroup Support
    00178  */
    00179 string extractBaseName(const StaticString &path);
    00180
    00181 /**
    00182  * Escape the given raw string into an XML value.
    00183  *
    00184  * @throws std::bad_alloc Something went wrong.
    00185  * @ingroup Support
    00186  */
    00187 string escapeForXml(const string &input);
    00188
    00189 /**
    00190  * Returns the username of the user that the current process is running as.
    00191  * If the user has no associated username, then "UID xxxx" is returned,
    00192  * where xxxx is the current UID.
    00193  */
    00194 string getProcessUsername();
    00195
    00196 /**
    00197  * Converts a mode string into a mode_t value.
    00198  *
    00199  * At this time only the symbolic mode strings are supported, e.g. something like looks
    00200  * this: "u=rwx,g=w,o=rx". The grammar is as follows:
    00201  * @code
    00202  *   mode   ::= (clause ("," clause)*)?
    00203  *   clause ::= who "=" permission*
    00204  *   who    ::= "u" | "g" | "o"
    00205  *   permission ::= "r" | "w" | "x" | "s"
    00206  * @endcode
    00207  *
    00208  * Notes:
    00209  * - The mode value starts with 0. So if you specify "u=rwx", then the group and world
    00210  *   permissions will be empty (set to 0).
    00211  * - The "s" permission is only allowed for who == "u" or who == "g".
    00212  * - The return value does not depend on the umask.
    00213  *
    00214  * @throws InvalidModeStringException The mode string cannot be parsed.
    00215  */
    00216 mode_t parseModeString(const StaticString &mode);
    00217
    00218 /**
    00219  * Return the path name for the directory in which the system stores general
    00220  * temporary files. This is usually "/tmp", but might be something else depending
    00221  * on some environment variables.
    00222  *
    00223  * @ensure result != NULL
    00224  * @ingroup Support
    00225  */
    00226 const char *getSystemTempDir();
    00227
    00228 /* Create a temporary directory for storing Phusion Passenger instance-specific
    00229  * temp files, such as temporarily buffered uploads, sockets for backend
    00230  * processes, etc.
    00231  * The directory that will be created is the one returned by
    00232  * <tt>getPassengerTempDir(false, parentDir)</tt>. This call stores the path to
    00233  * this temp directory in an internal variable, so that subsequent calls to
    00234  * getPassengerTempDir() will return the same path.
    00235  *
    00236  * The created temp directory will have several subdirectories:
    00237  * - webserver_private - for storing the web server's buffered uploads.
    00238  * - info - for storing files that allow external tools to query information
    00239  *          about a running Phusion Passenger instance.
    00240  * - backends - for storing Unix sockets created by backend processes.
    00241  * - master - for storing files such as the Passenger HelperServer socket.
    00242  *
    00243  * If a (sub)directory already exists, then it will not result in an error.
    00244  *
    00245  * The <em>userSwitching</em> and <em>lowestUser</em> arguments passed to
    00246  * this method are used for determining the optimal permissions for the
    00247  * (sub)directories. The permissions will be set as tightly as possible based
    00248  * on the values. The <em>workerUid</em> and <em>workerGid</em> arguments
    00249  * will be used for determining the owner of certain subdirectories.
    00250  *
    00251  * @note You should only call this method inside the web server's master
    00252  *       process. In case of Apache, this is the Apache control process,
    00253  *       the one that tends to run as root. This is because this function
    00254  *       will set directory permissions and owners/groups, which may require
    00255  *       root privileges.
    00256  *
    00257  * @param parentDir The directory under which the Phusion Passenger-specific
    00258  *                  temp directory should be created. This argument may be the
    00259  *                  empty string, in which case getSystemTempDir() will be used
    00260  *                  as the parent directory.
    00261  * @param userSwitching Whether user switching is turned on.
    00262  * @param lowestUser The user that the spawn manager and the pool server will
    00263  *                   run as, if user switching is turned off.
    00264  * @param workerUid The UID that the web server's worker processes are running
    00265  *                  as. On Apache, this is the UID that's associated with the
    00266  *                  'User' directive.
    00267  * @param workerGid The GID that the web server's worker processes are running
    00268  *                  as. On Apache, this is the GID that's associated with the
    00269  *                  'Group' directive.
    00270  * @throws IOException Something went wrong.
    00271  * @throws SystemException Something went wrong.
    00272  * @throws FileSystemException Something went wrong.
    00273  */
    00274 /* void createPassengerTempDir(const string &parentDir, bool userSwitching,
    00275                             const string &lowestUser,
    00276                             uid_t workerUid, gid_t workerGid); */
    00277
    00278 /**
    00279  * Create the directory at the given path, creating intermediate directories
    00280  * if necessary. The created directories' permissions are exactly as specified
    00281  * by the 'mode' parameter (i.e. the umask will be ignored). You can specify
    00282  * this directory's owner and group through the 'owner' and 'group' parameters.
    00283  * A value of USER_NOT_GIVEN for 'owner' and/or GROUP_NOT_GIVEN 'group' means
    00284  * that the owner/group should not be changed.
    00285  *
    00286  * If 'path' already exists, then nothing will happen.
    00287  *
    00288  * @param mode A mode string, as supported by parseModeString().
    00289  * @throws FileSystemException Something went wrong.
    00290  * @throws InvalidModeStringException The mode string cannot be parsed.
    00291  */
    00292 void makeDirTree(const string &path, const StaticString &mode = "u=rwx,g=,o=",
    00293         uid_t owner = USER_NOT_GIVEN, gid_t group = GROUP_NOT_GIVEN);
    00294
    00295 /**
    00296  * Remove an entire directory tree recursively. If the directory doesn't exist then this
    00297  * function does nothing.
    00298  *
    00299  * @throws FileSystemException Something went wrong.
    00300  */
    00301 void removeDirTree(const string &path);
    00302
    00303 /**
    00304  * Check whether the specified directory is a valid Ruby on Rails
    00305  * application root directory.
    00306  *
    00307  * @param cstat A CachedFileStat object, if you want to use cached statting.
    00308  * @param throttleRate A throttle rate for cstat. Only applicable if cstat is not NULL.
    00309  * @throws FileSystemException Unable to check because of a system error.
    00310  * @throws TimeRetrievalException
    00311  * @throws boost::thread_interrupted
    00312  * @ingroup Support
    00313  */
    00314 bool verifyRailsDir(const string &dir, CachedFileStat *cstat = 0,
    00315                     unsigned int throttleRate = 0);
    00316
    00317 /**
    00318  * Check whether the specified directory is a valid Rack application
    00319  * root directory.
    00320  *
    00321  * @param cstat A CachedFileStat object, if you want to use cached statting.
    00322  * @param throttleRate A throttle rate for cstat. Only applicable if cstat is not NULL.
    00323  * @throws FileSystemException Unable to check because of a filesystem error.
    00324  * @throws TimeRetrievalException
    00325  * @throws boost::thread_interrupted
    00326  * @ingroup Support
    00327  */
    00328 bool verifyRackDir(const string &dir, CachedFileStat *cstat = 0,
    00329                    unsigned int throttleRate = 0);
    00330
    00331 /**
    00332  * Check whether the specified directory is a valid WSGI application
    00333  * root directory.
    00334  *
    00335  * @param cstat A CachedFileStat object, if you want to use cached statting.
    00336  * @param throttleRate A throttle rate for cstat. Only applicable if cstat is not NULL.
    00337  * @throws FileSystemException Unable to check because of a filesystem error.
    00338  * @throws TimeRetrievalException
    00339  * @throws boost::thread_interrupted
    00340  * @ingroup Support
    00341  */
    00342 bool verifyWSGIDir(const string &dir, CachedFileStat *cstat = 0,
    00343                    unsigned int throttleRate = 0);
    00344
    00345 void prestartWebApps(const ResourceLocator &locator, const string &serializedprestartURLs);
    00346
    00347 /**
    00348  * Returns the system's host name.
    00349  *
    00350  * @throws SystemException The host name cannot be retrieved.
    00351  */
    00352 string getHostName();
    00353
    00354 /**
    00355  * Convert a signal number to its associated name.
    00356  */
    00357 string getSignalName(int sig);
    00358
    00359 /**
    00360  * Resets the current process's signal handler disposition and signal mask
    00361  * to default values. One should call this every time one forks a child process;
    00362  * non-default signal masks/handler dispositions can cause all kinds of weird quirks,
    00363  * like waitpid() malfunctioning on OS X.
    00364  *
    00365  * This function is async-signal safe.
    00366  */
    00367 void resetSignalHandlersAndMask();
    00368
    00369 /**
    00370  * Close all file descriptors that are higher than <em>lastToKeepOpen</em>.
    00371  * This function is async-signal safe. But make sure there are no other
    00372  * threads running that might open file descriptors!
    00373  */
    00374 void closeAllFileDescriptors(int lastToKeepOpen);
    00375
    00376
    00377 /**
    00378  * Represents a buffered upload file.
    00379  *
    00380  * @ingroup Support
    00381  */
    00382 class BufferedUpload {
    00383 public:
    00384         /** The file handle. */
    00385         FILE *handle;
    00386
    00387         /**
    00388          * Create an empty upload bufer file, and open it for reading and writing.
    00389          *
    00390          * @throws SystemException Something went wrong.
    00391          */
    00392         BufferedUpload(const string &dir, const char *identifier = "temp") {
    00393                 char templ[PATH_MAX];
    00394                 int fd;
    00395
    00396                 snprintf(templ, sizeof(templ), "%s/%s.XXXXXX", dir.c_str(), identifier);
    00397                 templ[sizeof(templ) - 1] = '\0';
    00398                 fd = mkstemp(templ);
    00399                 if (fd == -1) {
    00400                         char message[1024];
    00401                         int e = errno;
    00402
    00403                         snprintf(message, sizeof(message), "Cannot create a temporary file '%s'", templ);
    00404                         message[sizeof(message) - 1] = '\0';
    00405                         throw SystemException(message, e);
    00406                 }
    00407
    00408                 /* We use a POSIX trick here: the file's permissions are set to "u=,g=,o="
    00409                  * and the file is deleted immediately from the filesystem, while we
    00410                  * keep its file handle open. The result is that no other processes
    00411                  * will be able to access this file's contents anymore, except us.
    00412                  * We now have an anonymous disk-backed buffer.
    00413                  */
    00414                 fchmod(fd, 0000);
    00415                 unlink(templ);
    00416
    00417                 handle = fdopen(fd, "w+");
    00418         }
    00419
    00420         ~BufferedUpload() {
    00421                 fclose(handle);
    00422         }
    00423 };
    00424
    00425 } // namespace Passenger
    00426
    00427 #endif /* _PASSENGER_UTILS_H_ */
    00428