diff -ru xapian-core-0.9.10-orig/backends/flint/flint_database.cc xapian-core-0.9.10/backends/flint/flint_database.cc --- xapian-core-0.9.10-orig/backends/flint/flint_database.cc 2007-03-05 23:36:18.000000000 +0000 +++ xapian-core-0.9.10/backends/flint/flint_database.cc 2007-04-23 03:33:54.000000000 +0100 @@ -319,8 +319,16 @@ FlintDatabase::get_database_write_lock() { DEBUGCALL(DB, void, "FlintDatabase::get_database_write_lock", ""); - if (!lock.lock(true)) { - throw Xapian::DatabaseLockError("Unable to acquire database write lock on " + db_dir); + FlintLock::reason why = lock.lock(true); + if (why != FlintLock::SUCCESS) { + string msg("Unable to acquire database write lock on "); + msg += db_dir; + if (why == FlintLock::INUSE) { + msg += ": already locked"; + } else if (why == FlintLock::UNSUPPORTED) { + msg += ": locking probably not supported by this FS"; + } + throw Xapian::DatabaseLockError(msg); } } Only in xapian-core-0.9.10/backends/flint: flint_database.cc.orig diff -ru xapian-core-0.9.10-orig/backends/flint/flint_lock.cc xapian-core-0.9.10/backends/flint/flint_lock.cc --- xapian-core-0.9.10-orig/backends/flint/flint_lock.cc 2007-03-05 23:36:18.000000000 +0000 +++ xapian-core-0.9.10/backends/flint/flint_lock.cc 2007-04-23 03:38:08.000000000 +0100 @@ -1,6 +1,6 @@ /* flint_lock.cc: database locking for flint backend. * - * Copyright (C) 2005,2006 Olly Betts + * Copyright (C) 2005,2006,2007 Olly Betts * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as @@ -26,7 +26,6 @@ #include "safefcntl.h" #include #include -#include #include #include #include @@ -35,53 +34,83 @@ #include "flint_lock.h" +#include "omassert.h" + #ifdef __CYGWIN__ #include #endif -bool +FlintLock::reason FlintLock::lock(bool exclusive) { - (void)exclusive; // Ignore for now. + // Currently we only support exclusive locks. + (void)exclusive; + Assert(exclusive); +#if defined __CYGWIN__ || defined __WIN32__ + Assert(hFile == INVALID_HANDLE_VALUE); #ifdef __CYGWIN__ - if (hFile != INVALID_HANDLE_VALUE) return false; // Already locked!? char fnm[MAX_PATH]; cygwin_conv_to_win32_path(filename.c_str(), fnm); +#else + const char *fnm = filename.c_str(); +#endif hFile = CreateFile(fnm, GENERIC_WRITE, FILE_SHARE_READ, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); - return (hFile != INVALID_HANDLE_VALUE); -#elif defined __WIN32__ - if (hFile != INVALID_HANDLE_VALUE) return false; // Already locked!? - hFile = CreateFile(filename.c_str(), GENERIC_WRITE, FILE_SHARE_READ, - NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); - return (hFile != INVALID_HANDLE_VALUE); + if (hFile != INVALID_HANDLE_VALUE) return SUCCESS; + if (GetLastError() == ERROR_ALREADY_EXISTS) return INUSE; + return UNKNOWN; #else - if (fd >= 0) return false; // Already locked!? + Assert(fd == -1); int lockfd = open(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0600); - if (lockfd < 0) return false; // Couldn't open lockfile. + if (lockfd < 0) return UNKNOWN; // Couldn't open lockfile. int fds[2]; if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, fds) < 0) { // Couldn't create socketpair. close(lockfd); - return false; + return UNKNOWN; } pid_t child = fork(); if (child == 0) { // Child process. close(fds[0]); - struct flock fl; - fl.l_type = F_WRLCK; - fl.l_whence = SEEK_SET; - fl.l_start = 0; - fl.l_len = 1; - while (fcntl(lockfd, F_SETLK, &fl) == -1) { - if (errno == EINTR) continue; /* Interrupted by a signal. */ - // Lock failed. - // Just exit and the parent will realise. - exit(0); + + reason why = SUCCESS; + { + struct flock fl; + fl.l_type = F_WRLCK; + fl.l_whence = SEEK_SET; + fl.l_start = 0; + fl.l_len = 1; + while (fcntl(lockfd, F_SETLK, &fl) == -1) { + if (errno != EINTR) { + // Lock failed - translate known errno values into a reason + // code. + if (errno == EACCES || errno == EAGAIN) { + why = INUSE; + } else if (errno == ENOLCK) { + why = UNSUPPORTED; + } else { + _exit(0); + } + break; + } + } } - write(fds[1], "", 1); // Signal OK to parent. + + { + // Tell the parent if we got the lock, and if not, why not. + char ch = static_cast(why); + while (write(fds[1], &ch, 1) < 0) { + // EINTR means a signal interrupted us, so retry. + // Otherwise we're DOOMED! The best we can do is just exit + // and the parent process should get EOF and know the lock + // failed. + if (errno != EINTR) _exit(1); + } + if (why != SUCCESS) _exit(0); + } + //shutdown(fds[1], 1); // Disable further sends. // Connect pipe to stdin. dup2(fds[1], 0); @@ -90,7 +119,7 @@ // Emulate cat ourselves (we try to avoid this to reduce VM overhead). char ch; while (read(0, &ch, 1) != 0) { /* Do nothing */ } - exit(0); + _exit(0); } close(lockfd); @@ -99,25 +128,31 @@ // Couldn't fork. close(fds[0]); close(fds[1]); - return false; + return UNKNOWN; } - + // Parent process. close(fds[1]); while (true) { char ch; int n = read(fds[0], &ch, 1); - if (n == 1) break; // Got the lock. - if (n == 0) { - // EOF means lock failed. + if (n == 1) { + reason why = static_cast(ch); + if (why == SUCCESS) break; // Got the lock. close(fds[0]); - return false; + return why; + } + if (n == 0 || errno != EINTR) { + // EOF means the lock failed; we also treat unexpected errors from + // read() the same way. + close(fds[0]); + return UNKNOWN; } } //shutdown(fds[0], 0); // Disable further receives. fd = fds[0]; pid = child; - return true; + return SUCCESS; #endif } @@ -131,10 +166,15 @@ if (fd < 0) return; close(fd); fd = -1; - int status; - kill(pid, SIGHUP); - while (waitpid(pid, &status, 0) < 0) { - if (errno != EINTR) break; + // The only likely error from kill is ESRCH. The other possibilities + // (according to the Linux man page) are EINVAL (invalid signal) and EPERM + // (don't have permission to SIGHUP the process) but in none of the cases + // does calling waitpid do us any good! + if (kill(pid, SIGHUP) == 0) { + int status; + while (waitpid(pid, &status, 0) < 0) { + if (errno != EINTR) break; + } } #endif } Only in xapian-core-0.9.10/backends/flint: flint_lock.cc.orig Only in xapian-core-0.9.10/backends/flint: flint_lock.cc.rej diff -ru xapian-core-0.9.10-orig/backends/flint/flint_lock.h xapian-core-0.9.10/backends/flint/flint_lock.h --- xapian-core-0.9.10-orig/backends/flint/flint_lock.h 2007-03-05 23:36:18.000000000 +0000 +++ xapian-core-0.9.10/backends/flint/flint_lock.h 2007-04-23 03:38:27.000000000 +0100 @@ -1,6 +1,6 @@ /* flint_lock.h: database locking for flint backend. * - * Copyright (C) 2005,2006 Olly Betts + * Copyright (C) 2005,2006,2007 Olly Betts * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as @@ -14,7 +14,7 @@ * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 * USA */ @@ -35,7 +35,6 @@ #include #endif #include -#include #include #include #endif @@ -50,6 +49,12 @@ #endif public: + typedef enum { + SUCCESS, // We got the lock! + INUSE, // Already locked by someone else. + UNSUPPORTED, // Locking probably not supported (e.g. NFS without lockd). + UNKNOWN // The attempt failed for some unspecified reason. + } reason; #if defined __CYGWIN__ || defined __WIN32__ FlintLock(const std::string &filename_) : filename(filename_), hFile(INVALID_HANDLE_VALUE) { } @@ -59,7 +64,7 @@ operator bool() { return fd != -1; } #endif - bool lock(bool exclusive); + reason lock(bool exclusive); void release(); }; Only in xapian-core-0.9.10/backends/flint: flint_lock.h.orig