Author: kevans Date: Fri Jul 10 00:45:16 2020 New Revision: 363066 URL: https://svnweb.freebsd.org/changeset/base/363066
Log: memfd_create: turn on SHM_GROW_ON_WRITE memfd_create fds will no longer require an ftruncate(2) to set the size; they'll grow (to the extent that it's possible) upon write(2)-like syscalls. Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D25502 Modified: head/lib/libc/sys/shm_open.c head/sys/compat/linux/linux_file.c head/tests/sys/kern/memfd_test.c Modified: head/lib/libc/sys/shm_open.c ============================================================================== --- head/lib/libc/sys/shm_open.c Fri Jul 10 00:43:45 2020 (r363065) +++ head/lib/libc/sys/shm_open.c Fri Jul 10 00:45:16 2020 (r363066) @@ -84,7 +84,7 @@ memfd_create(const char *name, unsigned int flags) /* We've already validated that we're sufficiently sized. */ snprintf(memfd_name, NAME_MAX + 1, "%s%s", MEMFD_NAME_PREFIX, name); oflags = O_RDWR; - shmflags = 0; + shmflags = SHM_GROW_ON_WRITE; if ((flags & MFD_CLOEXEC) != 0) oflags |= O_CLOEXEC; if ((flags & MFD_ALLOW_SEALING) != 0) Modified: head/sys/compat/linux/linux_file.c ============================================================================== --- head/sys/compat/linux/linux_file.c Fri Jul 10 00:43:45 2020 (r363065) +++ head/sys/compat/linux/linux_file.c Fri Jul 10 00:45:16 2020 (r363066) @@ -1758,7 +1758,7 @@ linux_memfd_create(struct thread *td, struct linux_mem if ((flags & MFD_HUGETLB) != 0) return (ENOSYS); oflags = O_RDWR; - shmflags = 0; + shmflags = SHM_GROW_ON_WRITE; if ((flags & MFD_CLOEXEC) != 0) oflags |= O_CLOEXEC; if ((flags & MFD_ALLOW_SEALING) != 0) Modified: head/tests/sys/kern/memfd_test.c ============================================================================== --- head/tests/sys/kern/memfd_test.c Fri Jul 10 00:43:45 2020 (r363065) +++ head/tests/sys/kern/memfd_test.c Fri Jul 10 00:45:16 2020 (r363066) @@ -30,6 +30,7 @@ __FBSDID("$FreeBSD$"); #include <sys/fcntl.h> #include <sys/mman.h> +#include <sys/stat.h> #include <atf-c.h> #include <errno.h> @@ -38,18 +39,26 @@ __FBSDID("$FreeBSD$"); ATF_TC_WITHOUT_HEAD(basic); ATF_TC_BODY(basic, tc) { + struct stat sb; int fd; char buf[8]; ATF_REQUIRE((fd = memfd_create("...", 0)) != -1); - /* File size should be initially 0 */ - ATF_REQUIRE(write(fd, buf, sizeof(buf)) == 0); + /* write(2) should grow us out automatically. */ + ATF_REQUIRE(write(fd, buf, sizeof(buf)) == sizeof(buf)); + ATF_REQUIRE(fstat(fd, &sb) == 0); + ATF_REQUIRE(sb.st_size == sizeof(buf)); /* ftruncate(2) must succeed without seals */ - ATF_REQUIRE(ftruncate(fd, sizeof(buf) - 1) == 0); + ATF_REQUIRE(ftruncate(fd, 2 * (sizeof(buf) - 1)) == 0); - ATF_REQUIRE(write(fd, buf, sizeof(buf)) == sizeof(buf) - 1); + /* write(2) again must not be limited by ftruncate(2) size. */ + ATF_REQUIRE(write(fd, buf, sizeof(buf)) == sizeof(buf)); + + /* Sanity check. */ + ATF_REQUIRE(fstat(fd, &sb) == 0); + ATF_REQUIRE(sb.st_size == 2 * sizeof(buf)); close(fd); } _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
