auto import from //depot/cupcake/@135843
diff --git a/libc/unistd/pathconf.c b/libc/unistd/pathconf.c
new file mode 100644
index 0000000..032f918
--- /dev/null
+++ b/libc/unistd/pathconf.c
@@ -0,0 +1,273 @@
+/*
+ * 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 <pathconf.h>
+#include <sys/vfs.h>
+#include <sys/limits.h>
+#include <linux/ext2_fs.h>
+#include <linux/ext3_fs.h>
+#include <errno.h>
+
+/* these may not be defined yet by our headers */
+#ifndef _POSIX_VDISABLE
+#define _POSIX_VDISABLE -1
+#endif
+
+#ifndef _POSIX_SYNC_IO
+#define _POSIX_SYNC_IO -1
+#endif
+
+#ifndef _POSIX_PRIO_IO
+#define _POSIX_PRIO_IO -1
+#endif
+
+#ifndef _POSIX_ASYNC_IO
+#define _POSIX_ASYNC_IO -1
+#endif
+
+
+static long
+__filesizebits( struct statfs* s )
+{
+#define EOL_MAGIC 0x0000U
+
+ /* list of known 64-bit aware filesystems */
+ static const uint32_t known64[] = {
+ EXT2_SUPER_MAGIC,
+ UFS_MAGIC,
+ REISERFS_SUPER_MAGIC,
+ XFS_SUPER_MAGIC,
+ SMB_SUPER_MAGIC,
+ UDF_SUPER_MAGIC,
+ JFS_SUPER_MAGIC,
+ NTFS_SB_MAGIC,
+ VXFS_SUPER_MAGIC,
+ EOL_MAGIC
+ };
+ int nn = 0;
+
+ for (;;) {
+ if ( known64[nn] == EOL_MAGIC )
+ return 32;
+
+ if ( known64[nn] == s->f_type )
+ return 64;
+ }
+}
+
+
+static long
+__link_max( struct statfs* s )
+{
+ /* constant values were taken from official kernel headers.
+ * I don't think this justified bringing in <linux/minix_fs.h> et al
+ * into our cleaned-up kernel three
+ */
+ static const struct { uint32_t type; int max; } knownMax[] =
+ {
+ { EXT2_SUPER_MAGIC, EXT2_LINK_MAX },
+ { EXT3_SUPER_MAGIC, EXT3_LINK_MAX },
+ { MINIX_SUPER_MAGIC, 250 },
+ { MINIX2_SUPER_MAGIC, 65530 },
+ { REISERFS_SUPER_MAGIC, 0xffff - 1000 },
+ { UFS_MAGIC, 32000 },
+ { EOL_MAGIC, 0 }
+ };
+ int nn = 0;
+
+ for (;;) {
+ if ( knownMax[nn].type == EOL_MAGIC )
+ return LINK_MAX;
+
+ if ( knownMax[nn].type == s->f_type )
+ return knownMax[nn].max;
+ }
+ return LINK_MAX;
+}
+
+static long
+__2_symlinks( struct statfs* s )
+{
+ /* list of know filesystems that don't support symlinks */
+ static const uint32_t knownNoSymlinks[] = {
+ ADFS_SUPER_MAGIC, BFS_MAGIC, CRAMFS_MAGIC,
+ EFS_SUPER_MAGIC, MSDOS_SUPER_MAGIC, NTFS_SB_MAGIC,
+ QNX4_SUPER_MAGIC,
+ EOL_MAGIC
+ };
+ int nn = 0;
+
+ for (;;) {
+ if (knownNoSymlinks[nn] == 0)
+ return 1;
+ if (knownNoSymlinks[nn] == s->f_type)
+ return 0;
+ }
+}
+
+static long
+__name_max( struct statfs* s )
+{
+ return s->f_namelen;
+}
+
+long
+pathconf(const char *path, int name)
+{
+ struct statfs buf;
+ int ret = statfs( path, &buf );
+
+ if (ret < 0)
+ return -1;
+
+ switch (name) {
+ case _PC_FILESIZEBITS:
+ return __filesizebits(&buf);
+
+ case _PC_LINK_MAX:
+ return __link_max(&buf);
+
+ case _PC_MAX_CANON:
+ return MAX_CANON;
+
+ case _PC_MAX_INPUT:
+ return MAX_INPUT;
+
+ case _PC_NAME_MAX:
+ return __name_max(&buf);
+
+ case _PC_PATH_MAX:
+ return PATH_MAX;
+
+ case _PC_PIPE_BUF:
+ return PIPE_BUF;
+
+ case _PC_2_SYMLINKS:
+ return __2_symlinks(&buf);
+
+#if 0 /* don't know what to do there, the specs are really weird */
+ case _PC_ALLOC_SIZE_MIN:
+ case _PC_REC_INCR_XFER_SIZE:
+ case _PC_REC_MAX_XFER_SIZE:
+ case _PC_REC_MIN_XFER_SIZE:
+ case _PC_REC_XFER_ALIGN:
+#endif
+
+ case _PC_SYMLINK_MAX:
+ return -1; /* no limit */
+
+ case _PC_CHOWN_RESTRICTED:
+ return _POSIX_CHOWN_RESTRICTED;
+
+ case _PC_NO_TRUNC:
+ return _POSIX_NO_TRUNC;
+
+ case _PC_VDISABLE:
+ return _POSIX_VDISABLE;
+
+ case _PC_ASYNC_IO:
+ return _POSIX_ASYNC_IO;
+
+ case _PC_PRIO_IO:
+ return _POSIX_PRIO_IO;
+
+ case _PC_SYNC_IO:
+ return _POSIX_SYNC_IO;
+
+ default:
+ errno = EINVAL;
+ return -1;
+ }
+}
+
+long fpathconf(int fildes, int name)
+{
+ struct statfs buf;
+ int ret = fstatfs(fildes, &buf);
+
+ if (ret < 0)
+ return -1;
+
+ switch (name) {
+ case _PC_FILESIZEBITS:
+ return __filesizebits(&buf);
+
+ case _PC_LINK_MAX:
+ return __link_max(&buf);
+
+ case _PC_MAX_CANON:
+ return MAX_CANON;
+
+ case _PC_MAX_INPUT:
+ return MAX_INPUT;
+
+ case _PC_NAME_MAX:
+ return __name_max(&buf);
+
+ case _PC_PATH_MAX:
+ return PATH_MAX;
+
+ case _PC_PIPE_BUF:
+ return PIPE_BUF;
+
+ case _PC_2_SYMLINKS:
+ return __2_symlinks(&buf);
+
+#if 0 /* don't know what to do there, the specs are really weird */
+ case _PC_ALLOC_SIZE_MIN:
+ case _PC_REC_INCR_XFER_SIZE:
+ case _PC_REC_MAX_XFER_SIZE:
+ case _PC_REC_MIN_XFER_SIZE:
+ case _PC_REC_XFER_ALIGN:
+#endif
+
+ case _PC_SYMLINK_MAX:
+ return -1; /* no limit */
+
+ case _PC_CHOWN_RESTRICTED:
+ return _POSIX_CHOWN_RESTRICTED;
+
+ case _PC_NO_TRUNC:
+ return _POSIX_NO_TRUNC;
+
+ case _PC_VDISABLE:
+ return _POSIX_VDISABLE;
+
+ case _PC_ASYNC_IO:
+ return _POSIX_ASYNC_IO;
+
+ case _PC_PRIO_IO:
+ return _POSIX_PRIO_IO;
+
+ case _PC_SYNC_IO:
+ return _POSIX_SYNC_IO;
+
+ default:
+ errno = EINVAL;
+ return -1;
+ }
+}