X-Git-Url: http://git.indexdata.com/?p=idzebra-moved-to-github.git;a=blobdiff_plain;f=util%2Fflock.c;h=3157f3689cb1acc5a328bb68663ce92cf9266c43;hp=5956832e59dea6e6ef396f3a514783510f1d259c;hb=d513d15e315601b730b0b3a6126c3163d00223fb;hpb=b374ab328be4535cff9412e265a3fb87c53c1272 diff --git a/util/flock.c b/util/flock.c index 5956832..3157f36 100644 --- a/util/flock.c +++ b/util/flock.c @@ -1,8 +1,5 @@ -/* $Id: flock.c,v 1.10 2006-06-30 11:10:17 adam Exp $ - Copyright (C) 1995-2006 - Index Data ApS - -This file is part of the Zebra server. +/* This file is part of the Zebra server. + Copyright (C) 1994-2011 Index Data Zebra is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free @@ -15,12 +12,15 @@ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License -along with Zebra; see the file LICENSE.zebra. If not, write to the -Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA -02111-1307, USA. +along with this program; if not, write to the Free Software +Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ +#if HAVE_CONFIG_H +#include +#endif #include #include #include @@ -40,13 +40,12 @@ Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA #include #include -#define DEBUG_FLOCK 1 - -#define ALWAYS_FLOCK 1 - /** have this module (mutex) been initialized? */ static int initialized = 0; +/** whether fcntl locks are shared for all threads in a process (POSIX) */ +static int posix_locks = 1; + /** mutex for lock_list below */ Zebra_mutex lock_list_mutex; @@ -124,13 +123,17 @@ ZebraLockHandle zebra_lock_create(const char *dir, const char *name) assert(initialized); zebra_mutex_lock(&lock_list_mutex); -#ifndef WIN32 - for (p = lock_list; p ; p = p->next) - if (!strcmp(p->fname, fname)) - break; + /* see if we have the same filename in a global list of "lock files" */ +#ifndef WIN32 + if (posix_locks) + { + for (p = lock_list; p ; p = p->next) + if (!strcmp(p->fname, fname)) + break; + } #endif if (!p) - { + { /* didn't match (or we didn't want it to match! */ p = (struct zebra_lock_info *) xmalloc(sizeof(*p)); p->ref_count = 0; @@ -153,7 +156,9 @@ ZebraLockHandle zebra_lock_create(const char *dir, const char *name) p->fname = fname; fname = 0; /* fname buffer now owned by p->fname */ #ifndef WIN32 - zebra_lock_rdwr_init(&p->rdwr_lock); + if (posix_locks) + zebra_lock_rdwr_init(&p->rdwr_lock); + zebra_mutex_init(&p->file_mutex); p->no_file_write_lock = 0; p->no_file_read_lock = 0; @@ -164,6 +169,7 @@ ZebraLockHandle zebra_lock_create(const char *dir, const char *name) } if (p) { + /* we have lock info so we can make a handle pointing to that */ p->ref_count++; h = (ZebraLockHandle) xmalloc(sizeof(*h)); h->p = p; @@ -192,9 +198,8 @@ void zebra_lock_destroy(ZebraLockHandle h) --(h->p->ref_count); if (h->p->ref_count == 0) { + /* must remove shared info from lock_list */ struct zebra_lock_info **hp = &lock_list; - yaz_log(log_level, "zebra_lock_destroy fd=%d p=%p fname=%s remove", - h->p->fd, h, h->p->fname); while (*hp) { if (*hp == h->p) @@ -205,8 +210,13 @@ void zebra_lock_destroy(ZebraLockHandle h) else hp = &(*hp)->next; } + + yaz_log(log_level, "zebra_lock_destroy fd=%d p=%p fname=%s remove", + h->p->fd, h, h->p->fname); + #ifndef WIN32 - zebra_lock_rdwr_destroy(&h->p->rdwr_lock); + if (posix_locks) + zebra_lock_rdwr_destroy(&h->p->rdwr_lock); zebra_mutex_destroy(&h->p->file_mutex); #endif if (h->p->fd != -1) @@ -240,120 +250,161 @@ static int unixLock(int fd, int type, int cmd) int zebra_lock_w(ZebraLockHandle h) { - int r; - int do_lock = ALWAYS_FLOCK; + int r = 0; + int do_lock = 0; yaz_log(log_level, "zebra_lock_w fd=%d p=%p fname=%s begin", h->p->fd, h, h->p->fname); - + #ifdef WIN32 while ((r = _locking(h->p->fd, _LK_LOCK, 1))) ; #else + if (posix_locks) + zebra_lock_rdwr_wlock(&h->p->rdwr_lock); + zebra_mutex_lock(&h->p->file_mutex); if (h->p->no_file_write_lock == 0) do_lock = 1; h->p->no_file_write_lock++; - zebra_mutex_unlock(&h->p->file_mutex); if (do_lock) { - yaz_log(log_level, "zebra_lock_w fd=%d p=%p fname=%s 2", - h->p->fd, h, h->p->fname); /* if there is already a read lock.. upgrade to write lock */ r = unixLock(h->p->fd, F_WRLCK, F_SETLKW); } - yaz_log(log_level, "zebra_lock_w fd=%d p=%p fname=%s 3", - h->p->fd, h, h->p->fname); + else + { + assert(posix_locks); + } + zebra_mutex_unlock(&h->p->file_mutex); - zebra_lock_rdwr_wlock(&h->p->rdwr_lock); h->write_flag = 1; +#endif yaz_log(log_level, "zebra_lock_w fd=%d p=%p fname=%s end", h->p->fd, h, h->p->fname); -#endif return r; } int zebra_lock_r(ZebraLockHandle h) { - int r; - int do_lock = ALWAYS_FLOCK; + int r = 0; + int do_lock = 0; - yaz_log(log_level, "zebra_lock_r fd=%d p=%p fname=%s", + yaz_log(log_level, "zebra_lock_r fd=%d p=%p fname=%s begin", h->p->fd, h, h->p->fname); #ifdef WIN32 while ((r = _locking(h->p->fd, _LK_LOCK, 1))) ; #else + if (posix_locks) + zebra_lock_rdwr_rlock(&h->p->rdwr_lock); + zebra_mutex_lock(&h->p->file_mutex); if (h->p->no_file_read_lock == 0 && h->p->no_file_write_lock == 0) do_lock = 1; h->p->no_file_read_lock++; - zebra_mutex_unlock(&h->p->file_mutex); - if (do_lock) { /* only read lock if no write locks already */ r = unixLock(h->p->fd, F_RDLCK, F_SETLKW); } - - zebra_lock_rdwr_rlock(&h->p->rdwr_lock); + else + { + assert(posix_locks); + } + zebra_mutex_unlock(&h->p->file_mutex); + h->write_flag = 0; #endif + yaz_log(log_level, "zebra_lock_r fd=%d p=%p fname=%s end", + h->p->fd, h, h->p->fname); return r; } int zebra_unlock(ZebraLockHandle h) { int r = 0; - int do_unlock = ALWAYS_FLOCK; yaz_log(log_level, "zebra_unlock fd=%d p=%p fname=%s begin", h->p->fd, h, h->p->fname); #ifdef WIN32 r = _locking(h->p->fd, _LK_UNLCK, 1); #else - if (h->write_flag) - zebra_lock_rdwr_wunlock(&h->p->rdwr_lock); - else - zebra_lock_rdwr_runlock(&h->p->rdwr_lock); - zebra_mutex_lock(&h->p->file_mutex); if (h->write_flag) - h->p->no_file_write_lock--; + { + if (h->p->no_file_write_lock > 0) + h->p->no_file_write_lock--; + } else - h->p->no_file_read_lock--; + { + if (h->p->no_file_read_lock > 0) + h->p->no_file_read_lock--; + } if (h->p->no_file_read_lock == 0 && h->p->no_file_write_lock == 0) + r = unixLock(h->p->fd, F_UNLCK, F_SETLKW); + else { - do_unlock = 1; - yaz_log(log_level, "zebra_unlock fd=%d p=%p fname=%s 2", - h->p->fd, h, h->p->fname); + r = 0; + assert(posix_locks); } + zebra_mutex_unlock(&h->p->file_mutex); - if (do_unlock) - r = unixLock(h->p->fd, F_UNLCK, F_SETLKW); + if (posix_locks) + { + if (h->write_flag) + zebra_lock_rdwr_wunlock(&h->p->rdwr_lock); + else + zebra_lock_rdwr_runlock(&h->p->rdwr_lock); + } +#endif yaz_log(log_level, "zebra_unlock fd=%d p=%p fname=%s end", h->p->fd, h, h->p->fname); -#endif return r; } +/** \brief see if the fcntl locking is not POSIX + * + * The default posix_locks=1 is assumed.. This function sets posix_locks + * to zero if linuxthreads is in use. + */ +static int check_for_linuxthreads(void) +{ +#if __linux +#ifdef _CS_GNU_LIBPTHREAD_VERSION + char conf_buf[512]; + size_t r = confstr(_CS_GNU_LIBPTHREAD_VERSION, conf_buf, sizeof(conf_buf)); + if (r == 0) + { + yaz_log(YLOG_WARN|YLOG_ERRNO, "confstr failed"); + return -1; + } + if (strncmp(conf_buf, "linuxthreads", 12) == 0) + posix_locks = 0; /* Using linuxthreads.. */ +#else + posix_locks = 0; /* Old GLIBC on Linux. Assume linuxthreads */ +#endif +#endif + return 0; +} + void zebra_flock_init() { if (!initialized) { - log_level = yaz_log_module_level("flock"); -#if DEBUG_FLOCK - log_level = YLOG_LOG|YLOG_FLUSH; -#endif initialized = 1; + log_level = yaz_log_module_level("flock"); + yaz_log(log_level, "zebra_flock_init"); + check_for_linuxthreads(); zebra_mutex_init(&lock_list_mutex); + yaz_log(log_level, "posix_locks: %d", posix_locks); } - yaz_log(log_level, "zebra_flock_init"); } /* * Local variables: * c-basic-offset: 4 + * c-file-style: "Stroustrup" * indent-tabs-mode: nil * End: * vim: shiftwidth=4 tabstop=8 expandtab