diff options
Diffstat (limited to 'sysdeps/wordsize-64')
| -rw-r--r-- | sysdeps/wordsize-64/Makefile | 6 | ||||
| -rw-r--r-- | sysdeps/wordsize-64/tst-writev.c | 107 |
2 files changed, 113 insertions, 0 deletions
diff --git a/sysdeps/wordsize-64/Makefile b/sysdeps/wordsize-64/Makefile new file mode 100644 index 0000000000..9903f51f9a --- /dev/null +++ b/sysdeps/wordsize-64/Makefile @@ -0,0 +1,6 @@ +ifeq ($(subdir),misc) +tests += tst-writev + +# Time enough for a large writev syscall to complete. +tst-writev-ENV = TIMEOUTFACTOR="10" +endif diff --git a/sysdeps/wordsize-64/tst-writev.c b/sysdeps/wordsize-64/tst-writev.c new file mode 100644 index 0000000000..6e4788612c --- /dev/null +++ b/sysdeps/wordsize-64/tst-writev.c @@ -0,0 +1,107 @@ +/* Copyright (C) 2011 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ryan S. Arnold <rsa@us.ibm.com>, 2011. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <fcntl.h> +#include <paths.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <sys/uio.h> + + +/* The purpose of this test is to verify that the INTERNAL_[V]SYSCALL_NCS + macros on 64-bit platforms don't cast the return type to (int) which would + erroneously sign extend the return value should the high bit of the bottom + half of the word be '1'. */ + +#if 0 +/* Used to test the non power-of-2 code path. */ +#undef IOV_MAX +#define IOV_MAX 1000 +#endif + +/* writev() should report that it has written EXPECTED number of bytes. */ +#define EXPECTED ((size_t) INT32_MAX + 1) + +static int +do_test (void) +{ + struct iovec iv[IOV_MAX]; + /* POSIX doesn't guarantee that IOV_MAX is pow of 2 but we're optimistic. */ + size_t bufsz = EXPECTED / IOV_MAX; + size_t bufrem = EXPECTED % IOV_MAX; + + /* If there's a remainder then IOV_MAX probably isn't a power of 2 and we + need to make bufsz bigger so that the last iovec, iv[IOV_MAX-1], is free + for the remainder. */ + if (bufrem) + { + bufsz = bufsz + 1; + bufrem = EXPECTED - (bufsz * (IOV_MAX - 1)); + } + + /* We writev to /dev/null since we're just testing writev's return value. */ + int fd = open (_PATH_DEVNULL, O_WRONLY); + if (fd == -1) + { + printf ("Unable to open /dev/null for writing.\n"); + return -1; + } + + iv[0].iov_base = malloc (bufsz); + if (iv[0].iov_base == NULL) + { + printf ("malloc (%zu) failed.\n", bufsz); + close (fd); + return -1; + } + iv[0].iov_len = bufsz; + + /* We optimistically presume that there isn't a remainder and set all iovec + instances to the same base and len as the first instance. */ + for (int i = 1; i < IOV_MAX; i++) + { + /* We don't care what the data is so reuse the allocation from iv[0]; */ + iv[i].iov_base = iv[0].iov_base; + iv[i].iov_len = iv[0].iov_len; + } + + /* If there is a remainder then we correct the last iov_len. */ + if (bufrem) + iv[IOV_MAX - 1].iov_len = bufrem; + + /* Write junk to /dev/null with the writev syscall in order to get a return + of INT32_MAX+1 bytes to verify that the INTERNAL_SYSCALL wrappers aren't + mangling the result if the signbit of a 32-bit number is set. */ + ssize_t ret = writev (fd, iv, IOV_MAX); + + free (iv[0].iov_base); + close (fd); + + if (ret != (ssize_t) EXPECTED) + { + printf ("writev() return value: %zd != EXPECTED: %zd\n", ret, EXPECTED); + return 1; + } + + return 0; +} + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" |