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-rw-r--r--libc/sysdeps/linux/common/bits/uClibc_alloc.h26
-rw-r--r--libc/sysdeps/linux/common/getdents.c10
-rw-r--r--libc/sysdeps/linux/common/getdents64.c10
3 files changed, 40 insertions, 6 deletions
diff --git a/libc/sysdeps/linux/common/bits/uClibc_alloc.h b/libc/sysdeps/linux/common/bits/uClibc_alloc.h
new file mode 100644
index 000000000..6a70d27b7
--- /dev/null
+++ b/libc/sysdeps/linux/common/bits/uClibc_alloc.h
@@ -0,0 +1,26 @@
+/*
+ * Macros to transparently switch between the stack and heap for large
+ * allocations. The former is useful on MMU systems as it results in
+ * smaller code, but the latter is required on NoMMU systems. This is
+ * due to small stacks that cannot grow and so doing large allocs will
+ * cause a stack overflow.
+ *
+ * Copyright (C) 2010 Mike Frysinger <vapier@gentoo.org>
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ */
+
+#ifndef _UCLIBC_ALLOC_H
+#define _UCLIBC_ALLOC_H
+
+#include <alloca.h>
+#include <stdlib.h>
+
+#ifdef __ARCH_USE_MMU__
+# define stack_heap_alloc(x) alloca(x)
+# define stack_heap_free(x) do { if (0) free(x); } while (0)
+#else
+# define stack_heap_alloc(x) malloc(x)
+# define stack_heap_free(x) free(x)
+#endif
+
+#endif
diff --git a/libc/sysdeps/linux/common/getdents.c b/libc/sysdeps/linux/common/getdents.c
index 5dda190a8..46f7b8e16 100644
--- a/libc/sysdeps/linux/common/getdents.c
+++ b/libc/sysdeps/linux/common/getdents.c
@@ -4,7 +4,6 @@
* Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
*/
-#include <alloca.h>
#include <assert.h>
#include <errno.h>
#include <dirent.h>
@@ -17,6 +16,7 @@
#include <sys/syscall.h>
#include <bits/kernel_types.h>
#include <bits/kernel-features.h>
+#include <bits/uClibc_alloc.h>
#if !(defined __UCLIBC_HAS_LFS__ && defined __NR_getdents64 && __WORDSIZE == 64)
/* If the condition above is met, __getdents is defined as an alias
@@ -93,11 +93,13 @@ ssize_t __getdents (int fd, char *buf, size_t nbytes)
nbytes - size_diff);
dp = (struct dirent *) buf;
- skdp = kdp = alloca (red_nbytes);
+ skdp = kdp = stack_heap_alloc(red_nbytes);
retval = __syscall_getdents(fd, (unsigned char *)kdp, red_nbytes);
- if (retval == -1)
+ if (retval == -1) {
+ stack_heap_free(skdp);
return -1;
+ }
while ((char *) kdp < (char *) skdp + retval) {
const size_t alignment = __alignof__ (struct dirent);
@@ -114,6 +116,7 @@ ssize_t __getdents (int fd, char *buf, size_t nbytes)
if ((char *) dp == buf) {
/* The buffer the user passed in is too small to hold even
one entry. */
+ stack_heap_free(skdp);
__set_errno (EINVAL);
return -1;
}
@@ -130,6 +133,7 @@ ssize_t __getdents (int fd, char *buf, size_t nbytes)
dp = (struct dirent *) ((char *) dp + new_reclen);
kdp = (struct kernel_dirent *) (((char *) kdp) + kdp->d_reclen);
}
+ stack_heap_free(skdp);
return (char *) dp - buf;
}
diff --git a/libc/sysdeps/linux/common/getdents64.c b/libc/sysdeps/linux/common/getdents64.c
index 37cb4c6f8..30686f25a 100644
--- a/libc/sysdeps/linux/common/getdents64.c
+++ b/libc/sysdeps/linux/common/getdents64.c
@@ -5,7 +5,6 @@
*/
#include <features.h>
-#include <alloca.h>
#include <assert.h>
#include <errno.h>
#include <dirent.h>
@@ -17,6 +16,7 @@
#include <sys/types.h>
#include <sys/syscall.h>
#include <bits/kernel_types.h>
+#include <bits/uClibc_alloc.h>
#if defined __UCLIBC_HAS_LFS__ && defined __NR_getdents64
@@ -52,11 +52,13 @@ ssize_t __getdents64 (int fd, char *buf, size_t nbytes)
nbytes - size_diff);
dp = (struct dirent64 *) buf;
- skdp = kdp = alloca (red_nbytes);
+ skdp = kdp = stack_heap_alloc(red_nbytes);
retval = __syscall_getdents64(fd, (unsigned char *)kdp, red_nbytes);
- if (retval == -1)
+ if (retval == -1) {
+ stack_heap_free(skdp);
return -1;
+ }
while ((char *) kdp < (char *) skdp + retval) {
const size_t alignment = __alignof__ (struct dirent64);
@@ -73,6 +75,7 @@ ssize_t __getdents64 (int fd, char *buf, size_t nbytes)
if ((char *) dp == buf) {
/* The buffer the user passed in is too small to hold even
one entry. */
+ stack_heap_free(skdp);
__set_errno (EINVAL);
return -1;
}
@@ -89,6 +92,7 @@ ssize_t __getdents64 (int fd, char *buf, size_t nbytes)
dp = (struct dirent64 *) ((char *) dp + new_reclen);
kdp = (struct kernel_dirent64 *) (((char *) kdp) + kdp->d_reclen);
}
+ stack_heap_free(skdp);
return (char *) dp - buf;
}