libc/stdio/_fopen.c

   1 /* Copyright (C) 2004       Manuel Novoa III    <mjn3@codepoet.org>
   2  *
   3  * GNU Library General Public License (LGPL) version 2 or later.
   4  *
   5  * Dedicated to Toni.  See uClibc/DEDICATION.mjn3 for details.
   6  */
   7
   8 #include "_stdio.h"
   9
  10
  11 /*
  12  * Cases:
  13  *  fopen64  : filename != NULL, stream == NULL, filedes == -2
  14  *  fopen    : filename != NULL, stream == NULL, filedes == -1
  15  *  freopen  : filename != NULL, stream != NULL, filedes == -1
  16  *  fdopen   : filename == NULL, stream == NULL, filedes valid
  17  *
  18  *  fsfopen  : filename != NULL, stream != NULL, filedes == -1
  19  */
  20
  21 #if (O_ACCMODE != 3) || (O_RDONLY != 0) || (O_WRONLY != 1) || (O_RDWR != 2)
  22 #error Assumption violated - mode constants
  23 #endif
  24
  25 #ifndef O_LARGEFILE
  26 #define O_LARGEFILE 0
  27 #endif
  28
  29 /* Internal function -- reentrant (locks open file list) */
  30
  31 FILE attribute_hidden *_stdio_fopen(intptr_t fname_or_mode,
  32                                    register const char * __restrict mode,
  33                                    register FILE * __restrict stream, int filedes)
  34 {
  35         __mode_t open_mode;
  36         int i;
  37
  38         /* Parse the specified mode. */
  39         open_mode = O_RDONLY;
  40         if (*mode != 'r') {                     /* Not read... */
  41                 open_mode = (O_WRONLY | O_CREAT | O_TRUNC);
  42                 if (*mode != 'w') {             /* Not write (create or truncate)... */
  43                         open_mode = (O_WRONLY | O_CREAT | O_APPEND);
  44                         if (*mode != 'a') {     /* Not write (create or append)... */
  45                         DO_EINVAL:
  46                                 __set_errno(EINVAL); /* So illegal mode. */
  47                                 if (stream) {
  48                                 FREE_STREAM:
  49                                         assert(!(stream->__modeflags & __FLAG_FREEBUF));
  50                                         __STDIO_STREAM_FREE_FILE(stream);
  51                                 }
  52                                 return NULL;
  53                         }
  54                 }
  55         }
  56
  57         if ((mode[1] == 'b')) {         /* Binary mode (NO-OP currently). */
  58                 ++mode;
  59         }
  60
  61         if (mode[1] == '+') {                   /* Read and Write. */
  62                 ++mode;
  63                 open_mode |= (O_RDONLY | O_WRONLY);
  64                 open_mode += (O_RDWR - (O_RDONLY | O_WRONLY));
  65         }
  66
  67 #ifdef __UCLIBC_MJN3_ONLY__
  68 #warning CONSIDER: Implement glibc ccs option to bind a codeset?
  69 #warning CONSIDER: Implement glibc mmap option for readonly files?
  70 #warning CONSIDER: Implement a text mode using custom read/write funcs?
  71 #endif
  72 #if defined(__UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE__) || defined(__UCLIBC_HAS_FOPEN_LARGEFILE_MODE__)
  73
  74         while (*++mode) {
  75 # ifdef __UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE__
  76                 if (*mode == 'x') {        /* Open exclusive (a glibc extension). */
  77                         open_mode |= O_EXCL;
  78                         continue;
  79                 }
  80 # endif
  81 # ifdef __UCLIBC_HAS_FOPEN_LARGEFILE_MODE__
  82                 if (*mode == 'F') {             /* Open as large file (uClibc extension). */
  83                         open_mode |= O_LARGEFILE;
  84                         continue;
  85                 }
  86 # endif
  87         }
  88
  89 #endif
  90
  91         if (!stream) {            /* Need to allocate a FILE (not freopen). */
  92                 if ((stream = malloc(sizeof(FILE))) == NULL) {
  93                         return stream;
  94                 }
  95                 stream->__modeflags = __FLAG_FREEFILE;
  96 #ifdef __STDIO_BUFFERS
  97                 stream->__bufstart = NULL; /* We allocate a buffer below. */
  98 #endif
  99 #ifdef __UCLIBC_HAS_THREADS__
 100                 /* We only initialize the mutex in the non-freopen case. */
 101                 /* stream->__user_locking = _stdio_user_locking; */
 102                 STDIO_INIT_MUTEX(stream->__lock);
 103 #endif
 104         }
 105
 106 #ifdef __UCLIBC_MJN3_ONLY__
 107 #warning TODO: Verify fdopen append behavior of glibc.
 108 #endif
 109
 110         if (filedes >= 0) {                     /* Handle fdopen trickery. */
 111                 stream->__filedes = filedes;
 112                 /* NOTE: it is insufficient to just check R/W/RW agreement.
 113                  * We must also check largefile compatibility if applicable.
 114                  * Also, if append mode is desired for fdopen but O_APPEND isn't
 115                  * currently set, then set it as recommended by SUSv3.  However,
 116                  * if append mode is not specified for fdopen but O_APPEND is set,
 117                  * leave it set (glibc compat). */
 118                 i = (open_mode & (O_ACCMODE|O_LARGEFILE)) + 1;
 119
 120                 /* NOTE: fopencookie needs changing if the basic check changes! */
 121                 if ((i & ((int)fname_or_mode + 1)) != i) /* Basic agreement? */
 122                         goto DO_EINVAL;
 123                 if ((open_mode & ~(__mode_t)fname_or_mode) & O_APPEND) {
 124                         if (fcntl(filedes, F_SETFL, O_APPEND))  /* Need O_APPEND. */
 125                                 goto DO_EINVAL;
 126                 }
 127                 /* For later... to reflect largefile setting in stream flags. */
 128                 __STDIO_WHEN_LFS( open_mode |= (((__mode_t) fname_or_mode)
 129                                                                                 & O_LARGEFILE) );
 130         } else {
 131                 __STDIO_WHEN_LFS( if (filedes < -1) open_mode |= O_LARGEFILE );
 132                 if ((stream->__filedes = open(((const char *) fname_or_mode),
 133                                                                           open_mode, 0666)) < 0) {
 134                         goto FREE_STREAM;
 135                 }
 136         }
 137
 138         stream->__modeflags &= __FLAG_FREEFILE;
 139 /*      stream->__modeflags &= ~(__FLAG_READONLY|__FLAG_WRITEONLY); */
 140
 141         stream->__modeflags |=          /* Note: Makes assumptions about flag vals! */
 142 #if (O_APPEND != __FLAG_APPEND) || ((O_LARGEFILE != __FLAG_LARGEFILE) && (O_LARGEFILE != 0))
 143 # if (O_APPEND != __FLAG_APPEND)
 144                 ((open_mode & O_APPEND) ? __FLAG_APPEND : 0) |
 145 # else
 146                 (open_mode & O_APPEND) |
 147 # endif
 148 # if (O_LARGEFILE != __FLAG_LARGEFILE) && (O_LARGEFILE != 0)
 149                 ((open_mode & O_LARGEFILE) ? __FLAG_LARGEFILE : 0) |
 150 # else
 151                 (open_mode & O_LARGEFILE) |
 152 # endif
 153 #else
 154                 (open_mode & (O_APPEND|O_LARGEFILE)) | /* i386 linux and elks */
 155 #endif
 156                 ((((open_mode & O_ACCMODE) + 1) ^ 0x03) * __FLAG_WRITEONLY);
 157
 158 #ifdef __STDIO_BUFFERS
 159         if (stream->__filedes != INT_MAX) {
 160                 /* NB: fopencookie uses bogus filedes == INT_MAX,
 161                  * avoiding isatty() in that case.
 162                  */
 163                 i = errno; /* preserve errno against isatty call. */
 164                 if (isatty(stream->__filedes))
 165                         stream->__modeflags |= __FLAG_LBF;
 166                 __set_errno(i);
 167         }
 168
 169         if (!stream->__bufstart) {
 170                 if ((stream->__bufstart = malloc(BUFSIZ)) != NULL) {
 171                         stream->__bufend = stream->__bufstart + BUFSIZ;
 172                         stream->__modeflags |= __FLAG_FREEBUF;
 173                 } else {
 174 # if __STDIO_BUILTIN_BUF_SIZE > 0
 175                         stream->__bufstart = stream->__builtinbuf;
 176                         stream->__bufend = stream->__builtinbuf + sizeof(stream->__builtinbuf);
 177 # else  /* __STDIO_BUILTIN_BUF_SIZE > 0 */
 178                         stream->__bufend = stream->__bufstart;
 179 # endif /* __STDIO_BUILTIN_BUF_SIZE > 0 */
 180                 }
 181         }
 182
 183         __STDIO_STREAM_DISABLE_GETC(stream);
 184         __STDIO_STREAM_DISABLE_PUTC(stream);
 185         __STDIO_STREAM_INIT_BUFREAD_BUFPOS(stream);
 186 #endif
 187
 188         __STDIO_STREAM_RESET_GCS(stream);
 189
 190 #ifdef __UCLIBC_HAS_WCHAR__
 191         stream->__ungot_width[0] = 0;
 192 #endif
 193 #ifdef __STDIO_MBSTATE
 194         __INIT_MBSTATE(&(stream->__state));
 195 #endif
 196
 197 #ifdef __UCLIBC_HAS_THREADS__
 198         /* Even in the freopen case, we reset the user locking flag. */
 199         stream->__user_locking = _stdio_user_locking;
 200         /* STDIO_INIT_MUTEX(stream->__lock); */
 201 #endif
 202
 203 #ifdef __STDIO_HAS_OPENLIST
 204 #if defined(__UCLIBC_HAS_THREADS__) && defined(__STDIO_BUFFERS)
 205         if (!(stream->__modeflags & __FLAG_FREEFILE))
 206         {
 207                 /* An freopen call so the file was never removed from the list. */
 208         }
 209         else
 210 #endif
 211         {
 212                 /* We have to lock the del mutex in case another thread wants to fclose()
 213                  * the last file. */
 214                 __STDIO_THREADLOCK_OPENLIST_DEL;
 215                 __STDIO_THREADLOCK_OPENLIST_ADD;
 216                 stream->__nextopen = _stdio_openlist; /* New files are inserted at */
 217                 _stdio_openlist = stream;                         /*   the head of the list. */
 218                 __STDIO_THREADUNLOCK_OPENLIST_ADD;
 219                 __STDIO_THREADUNLOCK_OPENLIST_DEL;
 220         }
 221 #endif
 222
 223         __STDIO_STREAM_VALIDATE(stream);
 224
 225         return stream;
 226 }