libc: Fix alphasort() signature (and implementation).
The declaration for alphasort() in <dirent.h> used the deprecated:
int alphasort(const void*, const void*);
while both Posix and GLibc use instead:
int alphasort(const struct dirent** a, const struct dirent** b);
See: http://pubs.opengroup.org/onlinepubs/9699919799/functions/alphasort.html
This patch does the following:
- Update the declaration to match Posix/GLibc
- Get rid of the upstream BSD code which isn't compatible with the new
signature.
- Implement a new trivial alphasort() with the right signature, and
ensure that it uses strcoll() instead of strcmp().
- Remove Bionic-specific #ifdef .. #else .. #endif block in
dirent_test.cpp which uses alphasort().
Even through strcoll() currently uses strcmp(), this does the right
thing in the case where we decide to update strcoll() to properly
implement locale-specific ordered comparison.
Change-Id: I4fd45604d8a940aaf2eb0ecd7d73e2f11c9bca96
diff --git a/libc/bionic/dirent.cpp b/libc/bionic/dirent.cpp
new file mode 100644
index 0000000..3a7b5b4
--- /dev/null
+++ b/libc/bionic/dirent.cpp
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <private/ScopedPthreadMutexLocker.h>
+
+struct DIR {
+ int fd_;
+ size_t available_bytes_;
+ dirent* next_;
+ pthread_mutex_t mutex_;
+ dirent buff_[15];
+};
+
+static DIR* __allocate_DIR(int fd) {
+ DIR* d = reinterpret_cast<DIR*>(malloc(sizeof(DIR)));
+ if (d == NULL) {
+ return NULL;
+ }
+ d->fd_ = fd;
+ d->available_bytes_ = 0;
+ d->next_ = NULL;
+ pthread_mutex_init(&d->mutex_, NULL);
+ return d;
+}
+
+int dirfd(DIR* dirp) {
+ return dirp->fd_;
+}
+
+DIR* fdopendir(int fd) {
+ // Is 'fd' actually a directory?
+ struct stat sb;
+ if (fstat(fd, &sb) == -1) {
+ return NULL;
+ }
+ if (!S_ISDIR(sb.st_mode)) {
+ errno = ENOTDIR;
+ return NULL;
+ }
+
+ return __allocate_DIR(fd);
+}
+
+DIR* opendir(const char* path) {
+ int fd = open(path, O_RDONLY | O_DIRECTORY);
+ return (fd != -1) ? __allocate_DIR(fd) : NULL;
+}
+
+static bool __fill_DIR(DIR* d) {
+ int rc = TEMP_FAILURE_RETRY(getdents(d->fd_, d->buff_, sizeof(d->buff_)));
+ if (rc <= 0) {
+ return false;
+ }
+ d->available_bytes_ = rc;
+ d->next_ = d->buff_;
+ return true;
+}
+
+static dirent* __readdir_locked(DIR* d) {
+ if (d->available_bytes_ == 0 && !__fill_DIR(d)) {
+ return NULL;
+ }
+
+ dirent* entry = d->next_;
+ d->next_ = reinterpret_cast<dirent*>(reinterpret_cast<char*>(entry) + entry->d_reclen);
+ d->available_bytes_ -= entry->d_reclen;
+ return entry;
+}
+
+dirent* readdir(DIR* d) {
+ ScopedPthreadMutexLocker locker(&d->mutex_);
+ return __readdir_locked(d);
+}
+
+int readdir_r(DIR* d, dirent* entry, dirent** result) {
+ int saved_errno = errno;
+
+ *result = NULL;
+ errno = 0;
+
+ ScopedPthreadMutexLocker locker(&d->mutex_);
+
+ dirent* next = __readdir_locked(d);
+ if (errno != 0 && next == NULL) {
+ return errno;
+ }
+
+ if (next != NULL) {
+ memcpy(entry, next, next->d_reclen);
+ *result = entry;
+ }
+ errno = saved_errno;
+ return 0;
+}
+
+int closedir(DIR* d) {
+ if (d == NULL) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ int fd = d->fd_;
+ pthread_mutex_destroy(&d->mutex_);
+ free(d);
+ return close(fd);
+}
+
+void rewinddir(DIR* d) {
+ ScopedPthreadMutexLocker locker(&d->mutex_);
+ lseek(d->fd_, 0, SEEK_SET);
+ d->available_bytes_ = 0;
+}
+
+int scandir(const char* path, dirent*** namelist,
+ int(*filter)(const dirent*),
+ int(*compar)(const dirent**, const dirent**))
+{
+ int n_elem = 0;
+ dirent* this_de, *de;
+ dirent** de_list = NULL;
+ int de_list_size = 0;
+
+ DIR* d = opendir(path);
+ if (d == NULL) {
+ return -1;
+ }
+
+ while ((this_de = readdir(d)) != NULL) {
+ if (filter != NULL && (*filter)(this_de) == 0) {
+ continue;
+ }
+ if (n_elem == 0) {
+ de_list_size = 4;
+ de_list = (dirent**) malloc(sizeof(dirent*) * de_list_size);
+ if (de_list == NULL) {
+ return -1;
+ }
+ } else if (n_elem == de_list_size) {
+ de_list_size += 10;
+ dirent** de_list_new = (dirent**) realloc(de_list, sizeof(dirent*) * de_list_size);
+ if (de_list_new == NULL) {
+ free(de_list);
+ return -1;
+ }
+ de_list = de_list_new;
+ }
+ de = (dirent*) malloc(sizeof(dirent));
+ *de = *this_de;
+ de_list[n_elem++] = de;
+ }
+ closedir(d);
+ if (n_elem && compar) {
+ qsort(de_list, n_elem, sizeof(dirent*), (int (*)(const void*, const void*)) compar);
+ }
+ *namelist = de_list;
+ return n_elem;
+}
+
+int alphasort(const struct dirent** a, const struct dirent** b) {
+ return strcoll((*a)->d_name, (*b)->d_name);
+}