mirror of
https://github.com/ibm-s390-linux/s390-tools.git
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b627b8d8e1
This commit is based on the s390-tools-1.39.0 version. Changes on top of s390-tools-1.39.0: - Add MIT license to all source files - Add LICENSE file - Transform REAMDE to README.md (markdown) - Add AUTHORS.md file - Add CONTRIBUTING.md file - Move changelog from README to CHANGELOG.md file Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
95 lines
1.9 KiB
C
95 lines
1.9 KiB
C
/*
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* dump2tar - tool to dump files and command output into a tar archive
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*
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* Reference counting for directory handles
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*
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* Copyright IBM Corp. 2016, 2017
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*
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* s390-tools is free software; you can redistribute it and/or modify
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* it under the terms of the MIT license. See LICENSE for details.
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*/
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#include <dirent.h>
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#include <pthread.h>
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#include <sys/types.h>
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#include "dref.h"
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#include "global.h"
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#include "misc.h"
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/* dref_mutex serializes access to drefs */
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static pthread_mutex_t dref_mutex = PTHREAD_MUTEX_INITIALIZER;
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static unsigned long num_open_dirs;
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static unsigned long num_open_dirs_max;
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/* Lock dref mutex */
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static void dref_lock(void)
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{
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if (!global_threaded)
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return;
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pthread_mutex_lock(&dref_mutex);
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}
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/* Unlock dref mutex */
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static void dref_unlock(void)
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{
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if (!global_threaded)
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return;
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pthread_mutex_unlock(&dref_mutex);
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}
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/* Create a reference count managed directory handle for @dirname */
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struct dref *dref_create(const char *dirname)
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{
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struct dref *dref;
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DIR *dd;
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dd = opendir(dirname);
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DBG("opendir(%s)=%p (total=%lu)", dirname, dd, ++num_open_dirs);
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if (!dd) {
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num_open_dirs--;
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return NULL;
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}
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if (num_open_dirs > num_open_dirs_max)
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num_open_dirs_max = num_open_dirs;
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dref = mmalloc(sizeof(struct dref));
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dref->dd = dd;
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dref->dirfd = dirfd(dd);
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dref->count = 1;
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return dref;
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}
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/* Obtain a reference to @dref */
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struct dref *dref_get(struct dref *dref)
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{
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if (dref) {
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dref_lock();
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dref->count++;
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dref_unlock();
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}
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return dref;
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}
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/* Release a reference to @dref. If this was the last reference, lose the
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* associated directory handle and free @dref. */
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void dref_put(struct dref *dref)
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{
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if (dref) {
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dref_lock();
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dref->count--;
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if (dref->count == 0) {
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num_open_dirs--;
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DBG("closedir(%p) (total=%lu, max=%lu)", dref->dd,
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num_open_dirs, num_open_dirs_max);
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closedir(dref->dd);
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free(dref);
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}
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dref_unlock();
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}
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}
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