libc: add fallocate() and fallocate64()

We add the Linux-specific function fallocate() which allows the user to
directly manipulate allocate space for a file.  fallocate() can operate
in different modes, but the default mode is equivalent to posix_fallocate()
which is specified in POSIX.1.

Recent releases of e2fsprogs 1.42.11 and above expect fallocate64() to be
available.

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

5 files changed, 99 insertions, 29 deletions

diff --git a/libc/sysdeps/linux/common/Makefile.in b/libc/sysdeps/linux/common/Makefile.in
index dc3a4b7ff..85621544c 100644
--- a/libc/sysdeps/linux/common/Makefile.in
+++ b/libc/sysdeps/linux/common/Makefile.in
@@ -62,6 +62,10 @@ CSRC-$(UCLIBC_LINUX_SPECIFIC) += \
 	vmsplice.c
 CSRC-$(if $(findstring yy,$(UCLIBC_LINUX_SPECIFIC)$(UCLIBC_HAS_LFS)),y) += \
 	sendfile64.c
+# posix_fallocate() needs __libc_fallocate() from fallocate.c
+# posix_fallocate64() needs __libc_fallocate64() from fallocate64.c
+CSRC-$(if $(UCLIBC_LINUX_SPECIFIC)$(UCLIBC_HAS_ADVANCED_REALTIME),y,) += \
+	fallocate.c $(filter fallocate64.c,$(CSRC-y))
 # NPTL needs these internally: madvise.c
 CSRC-$(findstring y,$(UCLIBC_LINUX_SPECIFIC)$(UCLIBC_HAS_THREADS_NATIVE)) += madvise.c
 ifeq ($(UCLIBC_HAS_THREADS_NATIVE),y)
diff --git a/libc/sysdeps/linux/common/fallocate.c b/libc/sysdeps/linux/common/fallocate.c
new file mode 100644
index 000000000..b23122669
--- /dev/null
+++ b/libc/sysdeps/linux/common/fallocate.c
@@ -0,0 +1,48 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * fallocate() for uClibc - Based off of posix_fallocate() by Erik Andersen
+ * http://www.opengroup.org/onlinepubs/9699919799/functions/posix_fallocate.html
+ *
+ * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
+ *
+ * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
+ */
+
+#include <sys/syscall.h>
+#include <fcntl.h>
+#include <bits/kernel-features.h>
+#include <stdint.h>
+
+#if defined __NR_fallocate
+extern __typeof(fallocate) __libc_fallocate attribute_hidden;
+int attribute_hidden __libc_fallocate(int fd, int mode, __off_t offset, __off_t len)
+{
+	int ret;
+
+# if __WORDSIZE == 32
+	uint32_t off_low = offset;
+	uint32_t len_low = len;
+	/* may assert that these >>31 are 0 */
+	uint32_t zero = 0;
+	INTERNAL_SYSCALL_DECL(err);
+	ret = (int) (INTERNAL_SYSCALL(fallocate, err, 6, fd, mode,
+		__LONG_LONG_PAIR (zero, off_low),
+		__LONG_LONG_PAIR (zero, len_low)));
+# elif __WORDSIZE == 64
+	INTERNAL_SYSCALL_DECL(err);
+	ret = (int) (INTERNAL_SYSCALL(fallocate, err, 4, fd, mode, offset, len));
+# else
+# error your machine is neither 32 bit or 64 bit ... it must be magical
+# endif
+	if (unlikely(INTERNAL_SYSCALL_ERROR_P (ret, err)))
+		return INTERNAL_SYSCALL_ERRNO (ret, err);
+	return 0;
+}
+
+# if defined __UCLIBC_LINUX_SPECIFIC__ && defined __USE_GNU
+strong_alias(__libc_fallocate,fallocate)
+#  if __WORDSIZE == 64
+strong_alias(__libc_fallocate,fallocate64)
+#  endif
+# endif
+#endif
diff --git a/libc/sysdeps/linux/common/fallocate64.c b/libc/sysdeps/linux/common/fallocate64.c
new file mode 100644
index 000000000..cf75693d6
--- /dev/null
+++ b/libc/sysdeps/linux/common/fallocate64.c
@@ -0,0 +1,42 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * fallocate() for uClibc - based off posix_fallocate() by Erik Andersen
+ * http://www.opengroup.org/onlinepubs/9699919799/functions/posix_fallocate.html
+ *
+ * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
+ *
+ * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
+ */
+
+#include <sys/syscall.h>
+
+#include <fcntl.h>
+#include <bits/kernel-features.h>
+#include <stdint.h>
+
+#if defined __NR_fallocate
+
+# if __WORDSIZE == 64
+/* Can use normal fallocate() */
+# elif __WORDSIZE == 32
+extern __typeof(fallocate64) __libc_fallocate64 attribute_hidden;
+int attribute_hidden __libc_fallocate64(int fd, int mode, __off64_t offset,
+		__off64_t len)
+{
+	int ret;
+	INTERNAL_SYSCALL_DECL(err);
+	ret = (int) (INTERNAL_SYSCALL(fallocate, err, 6, fd, mode,
+		OFF64_HI_LO (offset), OFF64_HI_LO (len)));
+	if (unlikely(INTERNAL_SYSCALL_ERROR_P (ret, err)))
+		return INTERNAL_SYSCALL_ERRNO (ret, err);
+	return 0;
+}
+
+#  if defined __UCLIBC_LINUX_SPECIFIC__ && defined __USE_GNU
+strong_alias(__libc_fallocate64,fallocate64)
+#  endif
+
+# else
+# error your machine is neither 32 bit or 64 bit ... it must be magical
+# endif
+#endif
diff --git a/libc/sysdeps/linux/common/posix_fallocate.c b/libc/sysdeps/linux/common/posix_fallocate.c
index 9aaa6ce15..76771e353 100644
--- a/libc/sysdeps/linux/common/posix_fallocate.c
+++ b/libc/sysdeps/linux/common/posix_fallocate.c
@@ -14,28 +14,10 @@
 #include <stdint.h>
 
 #if defined __NR_fallocate
+extern __typeof(fallocate) __libc_fallocate attribute_hidden;
 int posix_fallocate(int fd, __off_t offset, __off_t len)
 {
-	int ret;
-
-# if __WORDSIZE == 32
-	uint32_t off_low = offset;
-	uint32_t len_low = len;
-	/* may assert that these >>31 are 0 */
-	uint32_t zero = 0;
-	INTERNAL_SYSCALL_DECL(err);
-	ret = (int) (INTERNAL_SYSCALL(fallocate, err, 6, fd, 0,
-		__LONG_LONG_PAIR (zero, off_low),
-		__LONG_LONG_PAIR (zero, len_low)));
-# elif __WORDSIZE == 64
-	INTERNAL_SYSCALL_DECL(err);
-	ret = (int) (INTERNAL_SYSCALL(fallocate, err, 4, fd, 0, offset, len));
-# else
-# error your machine is neither 32 bit or 64 bit ... it must be magical
-#endif
-    if (unlikely(INTERNAL_SYSCALL_ERROR_P (ret, err)))
-      return INTERNAL_SYSCALL_ERRNO (ret, err);
-    return 0;
+	return __libc_fallocate(fd, 0, offset, len);
 }
 # if defined __UCLIBC_HAS_LFS__ && __WORDSIZE == 64
 strong_alias(posix_fallocate,posix_fallocate64)
diff --git a/libc/sysdeps/linux/common/posix_fallocate64.c b/libc/sysdeps/linux/common/posix_fallocate64.c
index 76dc9b87e..12ddbc2bc 100644
--- a/libc/sysdeps/linux/common/posix_fallocate64.c
+++ b/libc/sysdeps/linux/common/posix_fallocate64.c
@@ -14,21 +14,15 @@
 #include <stdint.h>
 
 #if defined __NR_fallocate
-
 # if __WORDSIZE == 64
 /* Can use normal posix_fallocate() */
 # elif __WORDSIZE == 32
+extern __typeof(fallocate64) __libc_fallocate64 attribute_hidden;
 int posix_fallocate64(int fd, __off64_t offset, __off64_t len)
 {
-	int ret;
-	INTERNAL_SYSCALL_DECL(err);
-	ret = (int) (INTERNAL_SYSCALL(fallocate, err, 6, fd, 0,
-		OFF64_HI_LO (offset), OFF64_HI_LO (len)));
-    if (unlikely(INTERNAL_SYSCALL_ERROR_P (ret, err)))
-      return INTERNAL_SYSCALL_ERRNO (ret, err);
-    return 0;
+	return __libc_fallocate64(fd, 0, offset, len);
 }
 # else
-# error your machine is neither 32 bit or 64 bit ... it must be magical
+#  error your machine is neither 32 bit or 64 bit ... it must be magical
 # endif
 #endif