diff options
Diffstat (limited to 'libc-bottom-half/cloudlibc/src/libc/fcntl/openat.c')
-rw-r--r-- | libc-bottom-half/cloudlibc/src/libc/fcntl/openat.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/libc-bottom-half/cloudlibc/src/libc/fcntl/openat.c b/libc-bottom-half/cloudlibc/src/libc/fcntl/openat.c new file mode 100644 index 0000000..09cbbf8 --- /dev/null +++ b/libc-bottom-half/cloudlibc/src/libc/fcntl/openat.c @@ -0,0 +1,80 @@ +// Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/ +// +// SPDX-License-Identifier: BSD-2-Clause + +#include <assert.h> +#include <wasi/api.h> +#include <wasi/libc.h> +#include <errno.h> +#include <fcntl.h> +#include <string.h> + +static_assert(O_APPEND == __WASI_FDFLAGS_APPEND, "Value mismatch"); +static_assert(O_DSYNC == __WASI_FDFLAGS_DSYNC, "Value mismatch"); +static_assert(O_NONBLOCK == __WASI_FDFLAGS_NONBLOCK, "Value mismatch"); +static_assert(O_RSYNC == __WASI_FDFLAGS_RSYNC, "Value mismatch"); +static_assert(O_SYNC == __WASI_FDFLAGS_SYNC, "Value mismatch"); + +static_assert(O_CREAT >> 12 == __WASI_OFLAGS_CREAT, "Value mismatch"); +static_assert(O_DIRECTORY >> 12 == __WASI_OFLAGS_DIRECTORY, "Value mismatch"); +static_assert(O_EXCL >> 12 == __WASI_OFLAGS_EXCL, "Value mismatch"); +static_assert(O_TRUNC >> 12 == __WASI_OFLAGS_TRUNC, "Value mismatch"); + +int __wasilibc_nocwd_openat_nomode(int fd, const char *path, int oflag) { + // Compute rights corresponding with the access modes provided. + // Attempt to obtain all rights, except the ones that contradict the + // access mode provided to openat(). + __wasi_rights_t max = + ~(__WASI_RIGHTS_FD_DATASYNC | __WASI_RIGHTS_FD_READ | + __WASI_RIGHTS_FD_WRITE | __WASI_RIGHTS_FD_ALLOCATE | + __WASI_RIGHTS_FD_READDIR | __WASI_RIGHTS_FD_FILESTAT_SET_SIZE); + switch (oflag & O_ACCMODE) { + case O_RDONLY: + case O_RDWR: + case O_WRONLY: + if ((oflag & O_RDONLY) != 0) { + max |= __WASI_RIGHTS_FD_READ | __WASI_RIGHTS_FD_READDIR; + } + if ((oflag & O_WRONLY) != 0) { + max |= __WASI_RIGHTS_FD_DATASYNC | __WASI_RIGHTS_FD_WRITE | + __WASI_RIGHTS_FD_ALLOCATE | + __WASI_RIGHTS_FD_FILESTAT_SET_SIZE; + } + break; + case O_EXEC: + break; + case O_SEARCH: + break; + default: + errno = EINVAL; + return -1; + } + + // Ensure that we can actually obtain the minimal rights needed. + __wasi_fdstat_t fsb_cur; + __wasi_errno_t error = __wasi_fd_fdstat_get(fd, &fsb_cur); + if (error != 0) { + errno = error; + return -1; + } + + // Path lookup properties. + __wasi_lookupflags_t lookup_flags = 0; + if ((oflag & O_NOFOLLOW) == 0) + lookup_flags |= __WASI_LOOKUPFLAGS_SYMLINK_FOLLOW; + + // Open file with appropriate rights. + __wasi_fdflags_t fs_flags = oflag & 0xfff; + __wasi_rights_t fs_rights_base = max & fsb_cur.fs_rights_inheriting; + __wasi_rights_t fs_rights_inheriting = fsb_cur.fs_rights_inheriting; + __wasi_fd_t newfd; + error = __wasi_path_open(fd, lookup_flags, path, + (oflag >> 12) & 0xfff, + fs_rights_base, fs_rights_inheriting, fs_flags, + &newfd); + if (error != 0) { + errno = error; + return -1; + } + return newfd; +} |