From 15666878afb57439abfaf5c5a1f3a338f4e23104 Mon Sep 17 00:00:00 2001 From: Hallvard Furuseth Date: Tue, 27 Sep 2016 07:03:34 +0200 Subject: [PATCH] Move opening files to mdb_fopen() No change in functionality. --- libraries/liblmdb/mdb.c | 220 +++++++++++++++++++++++----------------- 1 file changed, 125 insertions(+), 95 deletions(-) diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c index 763972bdf8..0a7fcc02e8 100644 --- a/libraries/liblmdb/mdb.c +++ b/libraries/liblmdb/mdb.c @@ -4448,16 +4448,122 @@ mdb_fname_init(const char *path, unsigned envflags, MDB_name *fname) #define mdb_fname_destroy(fname) \ do { if ((fname).mn_alloced) free((fname).mn_val); } while (0) +#ifdef O_CLOEXEC /* POSIX.1-2008: Set FD_CLOEXEC atomically at open() */ +# define MDB_CLOEXEC O_CLOEXEC +#else +# define MDB_CLOEXEC 0 +#endif + +/** File type, access mode etc. for #mdb_fopen() */ enum mdb_fopen_type { - MDB_O_DATA, MDB_O_LOCKS +#ifdef _WIN32 + MDB_O_RDONLY, MDB_O_RDWR, MDB_O_META, MDB_O_COPY, MDB_O_LOCKS +#else + /* A comment in mdb_fopen() explains some O_* flag choices. */ + MDB_O_RDONLY= O_RDONLY, /**< for RDONLY me_fd */ + MDB_O_RDWR = O_RDWR |O_CREAT, /**< for me_fd */ + MDB_O_META = O_RDWR |MDB_DSYNC, /**< for me_mfd */ + MDB_O_COPY = O_WRONLY|O_CREAT|O_EXCL, /**< for #mdb_env_copy() */ + /** Bitmask for open() flags in enum #mdb_fopen_type. The other bits + * distinguish otherwise-equal MDB_O_* constants from each other. + */ + MDB_O_MASK = MDB_O_RDWR|MDB_CLOEXEC | MDB_O_RDONLY|MDB_O_META|MDB_O_COPY, + MDB_O_LOCKS = MDB_O_RDWR|MDB_CLOEXEC | ((MDB_O_MASK+1) & ~MDB_O_MASK) /**< for me_lfd */ +#endif }; -static void ESECT -mdb_fname_suffix_set(MDB_env *env, MDB_name *fname, enum mdb_fopen_type which) +/** Open an LMDB file. + * @param[in] env The LMDB environment. + * @param[in,out] fname Path from from #mdb_fname_init(). A suffix is + * appended if necessary to create the filename, without changing mn_len. + * @param[in] which Determines file type, access mode, etc. + * @param[in] mode The Unix permissions for the file, if we create it. + * @param[out] res Resulting file handle. + * @return 0 on success, non-zero on failure. + */ +static int ESECT +mdb_fopen(const MDB_env *env, MDB_name *fname, + enum mdb_fopen_type which, mdb_mode_t mode, + HANDLE *res) { + int rc = MDB_SUCCESS; + HANDLE fd; +#ifdef _WIN32 + DWORD acc, share, disp, attrs; +#else + int flags; +#endif + if (fname->mn_alloced) /* modifiable copy */ mdb_name_cpy(fname->mn_val + fname->mn_len, mdb_suffixes[which==MDB_O_LOCKS][F_ISSET(env->me_flags, MDB_NOSUBDIR)]); + + /* The directory must already exist. Usually the file need not. + * MDB_O_META requires the file because we already created it using + * MDB_O_RDWR. MDB_O_COPY must not overwrite an existing file. + * + * With MDB_O_COPY we do not want the OS to cache the writes, since + * the source data is already in the OS cache. + * + * The lockfile needs FD_CLOEXEC (close file descriptor on exec*()) + * to avoid the flock() issues noted under Caveats in lmdb.h. + */ + +#ifdef _WIN32 + acc = GENERIC_READ|GENERIC_WRITE; + share = FILE_SHARE_READ|FILE_SHARE_WRITE; + disp = OPEN_ALWAYS; + attrs = FILE_ATTRIBUTE_NORMAL; + switch (which) { + case MDB_O_RDONLY: /* read-only datafile */ + acc = GENERIC_READ; + disp = OPEN_EXISTING; + break; + case MDB_O_META: /* for writing metapages */ + disp = OPEN_EXISTING; + attrs = FILE_ATTRIBUTE_NORMAL|FILE_FLAG_WRITE_THROUGH; + break; + case MDB_O_COPY: /* mdb_env_copy() & co */ + acc = GENERIC_WRITE; + share = 0; + disp = CREATE_NEW; + attrs = FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH; + break; + default: break; /* silence gcc -Wswitch (not all enum values handled) */ + } + fd = CreateFileW(fname->mn_val, acc, share, NULL, disp, attrs, NULL); +#else + fd = open(fname->mn_val, which & MDB_O_MASK, mode); +#endif + + if (fd == INVALID_HANDLE_VALUE) + rc = ErrCode(); +#ifndef _WIN32 + else { + if (which == MDB_O_LOCKS) { + /* Set CLOEXEC if we could not pass it to open() */ + if (!MDB_CLOEXEC && (flags = fcntl(fd, F_GETFD)) != -1) + (void) fcntl(fd, F_SETFD, flags | FD_CLOEXEC); + } + if (which == MDB_O_COPY && env->me_psize >= env->me_os_psize) { + /* This may require buffer alignment. There is no portable + * way to ask how much, so we require OS pagesize alignment. + */ +# ifdef F_NOCACHE /* __APPLE__ */ + (void) fcntl(fd, F_NOCACHE, 1); +# elif defined O_DIRECT + /* open(...O_DIRECT...) would break on filesystems without + * O_DIRECT support (ITS#7682). Try to set it here instead. + */ + if ((flags = fcntl(fd, F_GETFL)) != -1) + (void) fcntl(fd, F_SETFL, flags | O_DIRECT); +# endif + } + } +#endif /* !_WIN32 */ + + *res = fd; + return rc; } @@ -4890,12 +4996,6 @@ mdb_env_setup_locks(MDB_env *env, MDB_name *fname, int mode, int *excl) # define MDB_ERRCODE_ROFS ERROR_WRITE_PROTECT #else # define MDB_ERRCODE_ROFS EROFS -#ifdef O_CLOEXEC /* Linux: Open file and set FD_CLOEXEC atomically */ -# define MDB_CLOEXEC O_CLOEXEC -#else -# define MDB_CLOEXEC 0 -#endif - int fdflags; #endif #ifdef MDB_USE_SYSV_SEM int semid; @@ -4904,26 +5004,14 @@ mdb_env_setup_locks(MDB_env *env, MDB_name *fname, int mode, int *excl) int rc; off_t size, rsize; - mdb_fname_suffix_set(env, fname, MDB_O_LOCKS); -#ifdef _WIN32 - env->me_lfd = CreateFileW(fname->mn_val, GENERIC_READ|GENERIC_WRITE, - FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, - FILE_ATTRIBUTE_NORMAL, NULL); -#else - env->me_lfd = open(fname->mn_val, O_RDWR|O_CREAT|MDB_CLOEXEC, mode); -#endif - if (env->me_lfd == INVALID_HANDLE_VALUE) { - rc = ErrCode(); + rc = mdb_fopen(env, fname, MDB_O_LOCKS, mode, &env->me_lfd); + if (rc) { + /* Omit lockfile if read-only env on read-only filesystem */ if (rc == MDB_ERRCODE_ROFS && (env->me_flags & MDB_RDONLY)) { return MDB_SUCCESS; } goto fail; } -#ifndef _WIN32 - /* Lose record locks when exec*() */ - if (!(MDB_CLOEXEC) && (fdflags = fcntl(env->me_lfd, F_GETFD)) != -1) - fcntl(env->me_lfd, F_SETFD, fdflags | FD_CLOEXEC); -#endif if (!(env->me_flags & MDB_NOTLS)) { rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest); @@ -5169,7 +5257,7 @@ fail: int ESECT mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode) { - int oflags, rc, len, excl = -1; + int rc, excl = -1; MDB_name fname; if (env->me_fd!=INVALID_HANDLE_VALUE || (flags & ~(CHANGEABLE|CHANGELESS))) @@ -5231,30 +5319,11 @@ mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode goto leave; } - mdb_fname_suffix_set(env, &fname, MDB_O_DATA); -#ifdef _WIN32 - if (F_ISSET(flags, MDB_RDONLY)) { - oflags = GENERIC_READ; - len = OPEN_EXISTING; - } else { - oflags = GENERIC_READ|GENERIC_WRITE; - len = OPEN_ALWAYS; - } - mode = FILE_ATTRIBUTE_NORMAL; - env->me_fd = CreateFileW(fname.mn_val, oflags, FILE_SHARE_READ|FILE_SHARE_WRITE, - NULL, len, mode, NULL); -#else - if (F_ISSET(flags, MDB_RDONLY)) - oflags = O_RDONLY; - else - oflags = O_RDWR | O_CREAT; - - env->me_fd = open(fname.mn_val, oflags, mode); -#endif - if (env->me_fd == INVALID_HANDLE_VALUE) { - rc = ErrCode(); + rc = mdb_fopen(env, &fname, + (flags & MDB_RDONLY) ? MDB_O_RDONLY : MDB_O_RDWR, + mode, &env->me_fd); + if (rc) goto leave; - } if ((flags & (MDB_RDONLY|MDB_NOLOCK)) == MDB_RDONLY) { rc = mdb_env_setup_locks(env, &fname, mode, &excl); @@ -5269,20 +5338,9 @@ mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode /* Synchronous fd for meta writes. Needed even with * MDB_NOSYNC/MDB_NOMETASYNC, in case these get reset. */ - mdb_fname_suffix_set(env, &fname, MDB_O_DATA); -#ifdef _WIN32 - len = OPEN_EXISTING; - env->me_mfd = CreateFileW(fname.mn_val, oflags, - FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, len, - mode | FILE_FLAG_WRITE_THROUGH, NULL); -#else - oflags &= ~O_CREAT; - env->me_mfd = open(fname.mn_val, oflags | MDB_DSYNC, mode); -#endif - if (env->me_mfd == INVALID_HANDLE_VALUE) { - rc = ErrCode(); + rc = mdb_fopen(env, &fname, MDB_O_META, mode, &env->me_mfd); + if (rc) goto leave; - } } DPRINTF(("opened dbenv %p", (void *) env)); if (excl > 0) { @@ -10176,43 +10234,15 @@ mdb_env_copy2(MDB_env *env, const char *path, unsigned int flags) HANDLE newfd = INVALID_HANDLE_VALUE; rc = mdb_fname_init(path, env->me_flags | MDB_NOLOCK, &fname); - if (rc) - return rc; - mdb_fname_suffix_set(env, &fname, MDB_O_DATA); - - /* The destination path must exist, but the destination file must not. - * We don't want the OS to cache the writes, since the source data is - * already in the OS cache. - */ -#ifdef _WIN32 - newfd = CreateFileW(fname.mn_val, GENERIC_WRITE, 0, NULL, CREATE_NEW, - FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH, NULL); -#else - newfd = open(fname.mn_val, O_WRONLY|O_CREAT|O_EXCL, 0666); -#endif - if (newfd == INVALID_HANDLE_VALUE) { - rc = ErrCode(); - goto leave; - } - - if (env->me_psize >= env->me_os_psize) { -#ifdef F_NOCACHE /* __APPLE__ */ - (void) fcntl(newfd, F_NOCACHE, 1); -#elif defined O_DIRECT - /* Set O_DIRECT if the file system supports it */ - if ((rc = fcntl(newfd, F_GETFL)) != -1) - (void) fcntl(newfd, F_SETFL, rc | O_DIRECT); -#endif + if (rc == MDB_SUCCESS) { + rc = mdb_fopen(env, &fname, MDB_O_COPY, 0666, &newfd); + mdb_fname_destroy(fname); } - - rc = mdb_env_copyfd2(env, newfd, flags); - -leave: - mdb_fname_destroy(fname); - if (newfd != INVALID_HANDLE_VALUE) + if (rc == MDB_SUCCESS) { + rc = mdb_env_copyfd2(env, newfd, flags); if (close(newfd) < 0 && rc == MDB_SUCCESS) rc = ErrCode(); - + } return rc; } -- 2.39.5