libc-top-half/musl/src/stdio/__fdopen.c

   1 #include "stdio_impl.h"
   2 #include <stdlib.h>
   3 #include <sys/ioctl.h>
   4 #include <fcntl.h>
   5 #include <errno.h>
   6 #include <string.h>
   7 #include "libc.h"
   8 #ifdef __wasilibc_unmodified_upstream // WASI has no syscall
   9 #else
  10 #include <__function___isatty.h>
  11 #endif
  12
  13 FILE *__fdopen(int fd, const char *mode)
  14 {
  15         FILE *f;
  16 #ifdef __wasilibc_unmodified_upstream // WASI has no syscall
  17         struct winsize wsz;
  18 #endif
  19
  20         /* Check for valid initial mode character */
  21         if (!strchr("rwa", *mode)) {
  22                 errno = EINVAL;
  23                 return 0;
  24         }
  25
  26         /* Allocate FILE+buffer or fail */
  27         if (!(f=malloc(sizeof *f + UNGET + BUFSIZ))) return 0;
  28
  29         /* Zero-fill only the struct, not the buffer */
  30         memset(f, 0, sizeof *f);
  31
  32         /* Impose mode restrictions */
  33         if (!strchr(mode, '+')) f->flags = (*mode == 'r') ? F_NOWR : F_NORD;
  34
  35         /* Apply close-on-exec flag */
  36 #ifdef __wasilibc_unmodified_upstream // WASI has no syscall
  37         if (strchr(mode, 'e')) __syscall(SYS_fcntl, fd, F_SETFD, FD_CLOEXEC);
  38 #else
  39         if (strchr(mode, 'e')) fcntl(fd, F_SETFD, FD_CLOEXEC);
  40 #endif
  41
  42         /* Set append mode on fd if opened for append */
  43         if (*mode == 'a') {
  44 #ifdef __wasilibc_unmodified_upstream // WASI has no syscall
  45                 int flags = __syscall(SYS_fcntl, fd, F_GETFL);
  46 #else
  47                 int flags = fcntl(fd, F_GETFL);
  48 #endif
  49                 if (!(flags & O_APPEND))
  50 #ifdef __wasilibc_unmodified_upstream // WASI has no syscall
  51                         __syscall(SYS_fcntl, fd, F_SETFL, flags | O_APPEND);
  52 #else
  53                         fcntl(fd, F_SETFL, flags | O_APPEND);
  54 #endif
  55                 f->flags |= F_APP;
  56         }
  57
  58         f->fd = fd;
  59         f->buf = (unsigned char *)f + sizeof *f + UNGET;
  60         f->buf_size = BUFSIZ;
  61
  62         /* Activate line buffered mode for terminals */
  63         f->lbf = EOF;
  64 #ifdef __wasilibc_unmodified_upstream // WASI has no syscall
  65         if (!(f->flags & F_NOWR) && !__syscall(SYS_ioctl, fd, TIOCGWINSZ, &wsz))
  66 #else
  67         if (!(f->flags & F_NOWR) && __isatty(fd))
  68 #endif
  69                 f->lbf = '\n';
  70
  71         /* Initialize op ptrs. No problem if some are unneeded. */
  72         f->read = __stdio_read;
  73         f->write = __stdio_write;
  74         f->seek = __stdio_seek;
  75         f->close = __stdio_close;
  76
  77 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
  78         if (!libc.threaded) f->lock = -1;
  79 #endif
  80
  81         /* Add new FILE to open file list */
  82         return __ofl_add(f);
  83 }
  84
  85 weak_alias(__fdopen, fdopen);