diff --git a/libports/lib/mk/libc.mk b/libports/lib/mk/libc.mk index 82bc6cbf7f..a7c7bb99ff 100644 --- a/libports/lib/mk/libc.mk +++ b/libports/lib/mk/libc.mk @@ -14,7 +14,7 @@ SRC_CC = atexit.cc dummies.cc rlimit.cc sysctl.cc readlink.cc munmap.cc \ issetugid.cc errno.cc gai_strerror.cc clock_gettime.cc \ gettimeofday.cc malloc.cc progname.cc fd_alloc.cc file_operations.cc \ plugin.cc plugin_registry.cc select.cc exit.cc environ.cc nanosleep.cc \ - libc_mem_alloc.cc writev.cc + libc_mem_alloc.cc writev.cc pread_pwrite.cc # # Files from string library that are not included in libc-raw_string because diff --git a/libports/src/lib/libc/pread_pwrite.cc b/libports/src/lib/libc/pread_pwrite.cc new file mode 100644 index 0000000000..3d90fdab69 --- /dev/null +++ b/libports/src/lib/libc/pread_pwrite.cc @@ -0,0 +1,75 @@ +/* + * \brief 'pread()' and 'pwrite()' implementations + * \author Christian Prochaska + * \date 2012-07-11 + */ + +/* + * Copyright (C) 2012 Genode Labs GmbH + * + * This file is part of the Genode OS framework, which is distributed + * under the terms of the GNU General Public License version 2. + */ + +/* Genode includes */ +#include + +/* libc includes */ +#include +#include +#include + + +static Genode::Lock rw_lock; + + +struct Read +{ + ssize_t operator()(int fd, void *buf, size_t count) + { + return read(fd, buf, count); + } +}; + + +struct Write +{ + ssize_t operator()(int fd, const void *buf, size_t count) + { + return write(fd, buf, count); + } +}; + + +template +static ssize_t pread_pwrite_impl(Rw_func rw_func, int fd, Buf_type buf, ::size_t count, ::off_t offset) +{ + Genode::Lock_guard rw_lock_guard(rw_lock); + + off_t old_offset = lseek(fd, 0, SEEK_CUR); + + if (old_offset == -1) + return -1; + + if (lseek(fd, offset, SEEK_SET) == -1) + return -1; + + ssize_t result = rw_func(fd, buf, count); + + if (lseek(fd, old_offset, SEEK_SET) == -1) + return -1; + + return result; +} + + +extern "C" ssize_t pread(int fd, void *buf, ::size_t count, ::off_t offset) +{ + return pread_pwrite_impl(Read(), fd, buf, count, offset); +} + + +extern "C" ssize_t pwrite(int fd, const void *buf, ::size_t count, ::off_t offset) +{ + return pread_pwrite_impl(Write(), fd, buf, count, offset); +} diff --git a/libports/src/test/libc_ffat/main.cc b/libports/src/test/libc_ffat/main.cc index 6d635e401e..ecc031f796 100644 --- a/libports/src/test/libc_ffat/main.cc +++ b/libports/src/test/libc_ffat/main.cc @@ -39,11 +39,15 @@ int main(int argc, char *argv[]) { int ret, fd; + ssize_t count; char const *dir_name = "/testdir"; char const *file_name = "test.tst"; + char const *file_name2 = "test2.tst"; char const *pattern = "a single line of text"; + size_t pattern_size = strlen(pattern) + 1; + unsigned int iterations = 1; try { @@ -60,8 +64,7 @@ int main(int argc, char *argv[]) /* write pattern to a file */ CALL_AND_CHECK(fd, open(file_name, O_CREAT | O_WRONLY), fd >= 0, "file_name=%s", file_name); - size_t count = strlen(pattern); - CALL_AND_CHECK(ret, write(fd, pattern, count), ret > 0, "count=%zd", count); + CALL_AND_CHECK(count, write(fd, pattern, pattern_size), (size_t)count == pattern_size, ""); CALL_AND_CHECK(ret, close(fd), ret == 0, ""); /* query file status of new file */ @@ -76,7 +79,7 @@ int main(int argc, char *argv[]) /* read and verify file content */ CALL_AND_CHECK(fd, open(file_name, O_RDONLY), fd >= 0, "file_name=%s", file_name); static char buf[512]; - CALL_AND_CHECK(count, read(fd, buf, sizeof(buf)), count > 0, ""); + CALL_AND_CHECK(count, read(fd, buf, sizeof(buf)), (size_t)count == pattern_size, ""); CALL_AND_CHECK(ret, close(fd), ret == 0, ""); printf("content of file: \"%s\"\n", buf); if (strcmp(buf, pattern) != 0) { @@ -86,6 +89,26 @@ int main(int argc, char *argv[]) printf("file content is correct\n"); } + /* test 'pread()' and 'pwrite()' */ + CALL_AND_CHECK(fd, open(file_name2, O_CREAT | O_WRONLY), fd >= 0, "file_name=%s", file_name); + /* write "a single line of" */ + CALL_AND_CHECK(count, pwrite(fd, pattern, (pattern_size - 6), 0), (size_t)count == (pattern_size - 6), ""); + /* write "line of text" at offset 9 */ + CALL_AND_CHECK(count, pwrite(fd, &pattern[9], (pattern_size - 9), 9), (size_t)count == (pattern_size - 9), ""); + CALL_AND_CHECK(ret, close(fd), ret == 0, ""); + CALL_AND_CHECK(fd, open(file_name2, O_RDONLY), fd >= 0, "file_name=%s", file_name); + memset(buf, 0, sizeof(buf)); + /* read "single line of text" from offset 2 */ + CALL_AND_CHECK(count, pread(fd, buf, sizeof(buf), 2), (size_t)count == (pattern_size - 2), ""); + CALL_AND_CHECK(ret, close(fd), ret == 0, ""); + printf("content of file: \"%s\"\n", buf); + if (strcmp(buf, &pattern[2]) != 0) { + printf("unexpected content of file\n"); + return -1; + } else { + printf("file content is correct\n"); + } + /* read directory entries */ DIR *dir; CALL_AND_CHECK(dir, opendir(dir_name), dir, "dir_name=\"%s\"", dir_name);