github.com/afumu/libc@v0.0.6/musl/src/fcntl/fcntl.c (about) 1 #define _GNU_SOURCE 2 #include <fcntl.h> 3 #include <stdarg.h> 4 #include <errno.h> 5 #include "syscall.h" 6 7 int fcntl(int fd, int cmd, ...) 8 { 9 unsigned long arg; 10 va_list ap; 11 va_start(ap, cmd); 12 arg = va_arg(ap, unsigned long); 13 va_end(ap); 14 if (cmd == F_SETFL) arg |= O_LARGEFILE; 15 if (cmd == F_SETLKW) return syscall_cp(SYS_fcntl, fd, cmd, (void *)arg); 16 if (cmd == F_GETOWN) { 17 struct f_owner_ex ex; 18 int ret = __syscall(SYS_fcntl, fd, F_GETOWN_EX, &ex); 19 if (ret == -EINVAL) return __syscall(SYS_fcntl, fd, cmd, (void *)arg); 20 if (ret) return __syscall_ret(ret); 21 return ex.type == F_OWNER_PGRP ? -ex.pid : ex.pid; 22 } 23 if (cmd == F_DUPFD_CLOEXEC) { 24 int ret = __syscall(SYS_fcntl, fd, F_DUPFD_CLOEXEC, arg); 25 if (ret != -EINVAL) { 26 if (ret >= 0) 27 __syscall(SYS_fcntl, ret, F_SETFD, FD_CLOEXEC); 28 return __syscall_ret(ret); 29 } 30 ret = __syscall(SYS_fcntl, fd, F_DUPFD_CLOEXEC, 0); 31 if (ret != -EINVAL) { 32 if (ret >= 0) __syscall(SYS_close, ret); 33 return __syscall_ret(-EINVAL); 34 } 35 ret = __syscall(SYS_fcntl, fd, F_DUPFD, arg); 36 if (ret >= 0) __syscall(SYS_fcntl, ret, F_SETFD, FD_CLOEXEC); 37 return __syscall_ret(ret); 38 } 39 switch (cmd) { 40 case F_SETLK: 41 case F_GETLK: 42 case F_GETOWN_EX: 43 case F_SETOWN_EX: 44 return syscall(SYS_fcntl, fd, cmd, (void *)arg); 45 default: 46 return syscall(SYS_fcntl, fd, cmd, arg); 47 } 48 }