diff --git a/src/stat/fchmodat.c b/src/stat/fchmodat.c index 61d3206553e6770d18ae1b53bda2f071fb5e7768..c1410bc58d2fe311e9d5bc73e31fbf78951deead 100644 --- a/src/stat/fchmodat.c +++ b/src/stat/fchmodat.c @@ -1,7 +1,35 @@ #include +#include +#include +#include #include "syscall.h" int fchmodat(int fd, const char *path, mode_t mode, int flag) { - return syscall(SYS_fchmodat, fd, path, mode, flag); + if (!flag) return syscall(SYS_fchmodat, fd, path, mode, flag); + + if (flag != AT_SYMLINK_NOFOLLOW) + return __syscall_ret(-EINVAL); + + struct stat st; + int ret, fd2; + char proc[15+3*sizeof(int)]; + + if ((ret = __syscall(SYS_fstatat, fd, path, &st, flag))) + return __syscall_ret(ret); + if (S_ISLNK(st.st_mode)) + return __syscall_ret(-EOPNOTSUPP); + + if ((fd2 = __syscall(SYS_openat, fd, path, O_RDONLY|O_PATH|O_NOFOLLOW|O_NOCTTY)) < 0) { + if (fd2 == -ELOOP) + return __syscall_ret(-EOPNOTSUPP); + return __syscall_ret(fd2); + } + + snprintf(proc, sizeof proc, "/proc/self/fd/%d", fd2); + if (!(ret = __syscall(SYS_stat, proc, &st)) && !S_ISLNK(st.st_mode)) + ret = __syscall(SYS_chmod, proc, mode); + + __syscall(SYS_close, fd2); + return __syscall_ret(ret); }