Reimplement scandir(3).
The old scandir implementation didn't take into account the varying
size of directory entries, and didn't correctly clean up on its
error exits.
Bug: 7339844
Change-Id: Ib40e3564709752241a3119a496cbb2192e3f9abe
diff --git a/libc/Android.mk b/libc/Android.mk
index 5a1356a..7219211 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -293,6 +293,7 @@
bionic/pthread_sigmask.cpp \
bionic/raise.cpp \
bionic/sbrk.cpp \
+ bionic/scandir.cpp \
bionic/__set_errno.cpp \
bionic/setlocale.cpp \
bionic/signalfd.cpp \
diff --git a/libc/bionic/dirent.cpp b/libc/bionic/dirent.cpp
index 74297d8..0565698 100644
--- a/libc/bionic/dirent.cpp
+++ b/libc/bionic/dirent.cpp
@@ -27,11 +27,9 @@
*/
#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>
@@ -146,51 +144,6 @@
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) {
+int alphasort(const dirent** a, const dirent** b) {
return strcoll((*a)->d_name, (*b)->d_name);
}
diff --git a/libc/bionic/scandir.cpp b/libc/bionic/scandir.cpp
new file mode 100644
index 0000000..dd22b22
--- /dev/null
+++ b/libc/bionic/scandir.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <dirent.h>
+
+#include <errno.h>
+#include <stdlib.h>
+
+#include "private/ScopedReaddir.h"
+
+// A smart pointer to the scandir dirent**.
+class ScandirResult {
+ public:
+ ScandirResult() : names_(NULL), size_(0), capacity_(0) {
+ }
+
+ ~ScandirResult() {
+ while (size_ > 0) {
+ free(names_[--size_]);
+ }
+ free(names_);
+ }
+
+ size_t size() {
+ return size_;
+ }
+
+ dirent** release() {
+ dirent** result = names_;
+ names_ = NULL;
+ size_ = capacity_ = 0;
+ return result;
+ }
+
+ bool Add(dirent* entry) {
+ if (size_ >= capacity_) {
+ size_t new_capacity = capacity_ + 32;
+ dirent** new_names = (dirent**) realloc(names_, new_capacity * sizeof(dirent*));
+ if (new_names == NULL) {
+ return false;
+ }
+ names_ = new_names;
+ capacity_ = new_capacity;
+ }
+
+ dirent* copy = CopyDirent(entry);
+ if (copy == NULL) {
+ return false;
+ }
+ names_[size_++] = copy;
+ return true;
+ }
+
+ void Sort(int (*comparator)(const dirent**, const dirent**)) {
+ // If we have entries and a comparator, sort them.
+ if (size_ > 0 && comparator != NULL) {
+ qsort(names_, size_, sizeof(dirent*), (int (*)(const void*, const void*)) comparator);
+ }
+ }
+
+ private:
+ dirent** names_;
+ size_t size_;
+ size_t capacity_;
+
+ static dirent* CopyDirent(dirent* original) {
+ // Allocate the minimum number of bytes necessary, rounded up to a 4-byte boundary.
+ size_t size = ((original->d_reclen + 3) & ~3);
+ dirent* copy = (dirent*) malloc(size);
+ memcpy(copy, original, original->d_reclen);
+ return copy;
+ }
+
+ // Disallow copy and assignment.
+ ScandirResult(const ScandirResult&);
+ void operator=(const ScandirResult&);
+};
+
+int scandir(const char* dirname, dirent*** name_list,
+ int (*filter)(const dirent*),
+ int (*comparator)(const dirent**, const dirent**)) {
+ ScopedReaddir reader(dirname);
+ if (reader.IsBad()) {
+ return -1;
+ }
+
+ ScandirResult names;
+ dirent* entry;
+ while ((entry = reader.ReadEntry()) != NULL) {
+ // If we have a filter, skip names that don't match.
+ if (filter != NULL && !(*filter)(entry)) {
+ continue;
+ }
+ names.Add(entry);
+ }
+
+ names.Sort(comparator);
+
+ size_t size = names.size();
+ *name_list = names.release();
+ return size;
+}
diff --git a/libc/bionic/sysconf.cpp b/libc/bionic/sysconf.cpp
index 869faef..5e39e61 100644
--- a/libc/bionic/sysconf.cpp
+++ b/libc/bionic/sysconf.cpp
@@ -39,6 +39,8 @@
#include <time.h>
#include <unistd.h>
+#include "private/ScopedReaddir.h"
+
/* seems to be the default on Linux, per the GLibc sources and my own digging */
#define SYSTEM_CLK_TCK 100
@@ -78,19 +80,18 @@
static int __sysconf_nprocessors_conf() {
// On x86 kernels you can use /proc/cpuinfo for this, but on ARM kernels offline CPUs disappear
// from there. This method works on both.
- DIR* d = opendir("/sys/devices/system/cpu");
- if (!d) {
+ ScopedReaddir reader("/sys/devices/system/cpu");
+ if (reader.IsBad()) {
return 1;
}
int result = 0;
- struct dirent* e;
- while ((e = readdir(d)) != NULL) {
- if (e->d_type == DT_DIR && __matches_cpuN(e->d_name)) {
+ dirent* entry;
+ while ((entry = reader.ReadEntry()) != NULL) {
+ if (entry->d_type == DT_DIR && __matches_cpuN(entry->d_name)) {
++result;
}
}
- closedir(d);
return result;
}
diff --git a/libc/private/ScopedReaddir.h b/libc/private/ScopedReaddir.h
new file mode 100644
index 0000000..797809a
--- /dev/null
+++ b/libc/private/ScopedReaddir.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SCOPED_READDIR_H
+#define SCOPED_READDIR_H
+
+#include <dirent.h>
+
+class ScopedReaddir {
+ public:
+ ScopedReaddir(const char* path) {
+ dir_ = opendir(path);
+ }
+
+ ~ScopedReaddir() {
+ if (dir_ != NULL) {
+ closedir(dir_);
+ }
+ }
+
+ bool IsBad() {
+ return dir_ == NULL;
+ }
+
+ dirent* ReadEntry() {
+ return readdir(dir_);
+ }
+
+ private:
+ DIR* dir_;
+
+ // Disallow copy and assignment.
+ ScopedReaddir(const ScopedReaddir&);
+ void operator=(const ScopedReaddir&);
+};
+
+#endif // SCOPED_READDIR_H