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[/] [openrisc/] [trunk/] [gnu-stable/] [newlib-1.18.0/] [newlib/] [libc/] [sys/] [mmixware/] [open.c] - Rev 816
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/* open for MMIXware. Copyright (C) 2001, 2002 Hans-Peter Nilsson Permission to use, copy, modify, and distribute this software is freely granted, provided that the above copyright notice, this notice and the following disclaimer are preserved with no changes. THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #include <stdlib.h> #include <fcntl.h> #include <_ansi.h> #include <sys/types.h> #include <sys/stat.h> #include "sys/syscall.h" #include <errno.h> /* Let's keep the filehandle array here, since this is a primary initializer of it. */ unsigned char _MMIX_allocated_filehandle[32] = { 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; int _open (const char *path, int flags, ...) { long fileno; unsigned char mode; long append_contents = 0; unsigned long prev_contents_size = 0; char *prev_contents = NULL; long ret; for (fileno = 0; fileno < (sizeof (_MMIX_allocated_filehandle) / sizeof (_MMIX_allocated_filehandle[0])); fileno++) if (_MMIX_allocated_filehandle[fileno] == 0) break; if (fileno == (sizeof (_MMIX_allocated_filehandle) / sizeof (_MMIX_allocated_filehandle[0]))) { errno = EMFILE; return -1; } /* We map this to a fopen call. The flags parameter is stymied because we don't support other than these flags. */ if (flags & ~(O_RDONLY | O_WRONLY | O_RDWR | O_CREAT | O_APPEND | O_TRUNC)) { UNIMPLEMENTED (("path: %s, flags: %d", path, flags)); errno = ENOSYS; return -1; } if ((flags & O_ACCMODE) == O_RDONLY) mode = BinaryRead; else if ((flags & (O_WRONLY | O_APPEND)) == (O_WRONLY | O_APPEND)) { mode = BinaryReadWrite; append_contents = 1; } else if ((flags & (O_RDWR | O_APPEND)) == (O_RDWR | O_APPEND)) { mode = BinaryReadWrite; append_contents = 1; } else if ((flags & (O_WRONLY | O_CREAT)) == (O_WRONLY | O_CREAT) || (flags & (O_WRONLY | O_TRUNC)) == (O_WRONLY | O_TRUNC)) mode = BinaryWrite; else if ((flags & (O_RDWR | O_CREAT)) == (O_RDWR | O_CREAT)) mode = BinaryReadWrite; else if (flags & O_RDWR) mode = BinaryReadWrite; else { errno = EINVAL; return -1; } if (append_contents) { /* BinaryReadWrite is equal to "w+", so it truncates the file rather than keeping the contents, as can be imagined if you're looking for append functionality. The only way we can keep the contents so we can append to it, is by first reading in and saving the contents, then re-opening the file as BinaryReadWrite and write the previous contents. This seems to work for the needs of simple test-programs. */ long openexist = TRAP3f (SYS_Fopen, fileno, path, BinaryRead); if (openexist == 0) { /* Yes, this file exists, now opened, so let's read it and keep the contents. Better have the memory around for this to work. */ long seekval = TRAP2f (SYS_Fseek, fileno, -1); if (seekval == 0) { prev_contents_size = TRAP1f (SYS_Ftell, fileno); /* If the file has non-zero size, we have something to append to. */ if (prev_contents_size != 0) { /* Start reading from the beginning. Ignore the return value from this call: we'll notice if we can't read as much as we want. */ TRAP2f (SYS_Fseek, fileno, 0); prev_contents = malloc (prev_contents_size); if (prev_contents != 0) { /* I don't like the thought of trying to read the whole file all at once, disregarding the size, because the host system might not support that and we'd get funky errors. Read in 32k at a time. */ char *ptr = prev_contents; unsigned long read_more = prev_contents_size; unsigned long chunk_size = 1 << 15; while (read_more >= chunk_size) { long readval = TRAP3f (SYS_Fread, fileno, ptr, chunk_size); if (readval != 0) { free (prev_contents); TRAP1f (SYS_Fclose, fileno); errno = EIO; return -1; } read_more -= chunk_size; ptr += chunk_size; } if (read_more != 0) { long readval = TRAP3f (SYS_Fread, fileno, ptr, read_more); if (readval != 0) { free (prev_contents); TRAP1f (SYS_Fclose, fileno); errno = EIO; return -1; } } } else { /* Malloc of area to copy to failed. The glibc manpage says its open can return ENOMEM due to kernel memory failures, so let's do that too here. */ errno = ENOMEM; return -1; } } } else { /* Seek failed. Gotta be some I/O error. */ errno = EIO; return -1; } TRAP1f (SYS_Fclose, fileno); } } ret = TRAP3f (SYS_Fopen, fileno, path, mode); if (ret < 0) { /* It's totally unknown what the error was. We'll just take our chances and assume ENOENT. */ errno = ENOENT; return -1; } if (prev_contents_size != 0) { /* Write out the previous contents, a chunk at a time. Leave the file pointer at the end of the file. */ unsigned long write_more = prev_contents_size; unsigned long chunk_size = 1 << 15; char *ptr = prev_contents; while (write_more >= chunk_size) { long writeval = TRAP3f (SYS_Fwrite, fileno, ptr, chunk_size); if (writeval != 0) { free (prev_contents); TRAP1f (SYS_Fclose, fileno); errno = EIO; return -1; } write_more -= chunk_size; ptr += chunk_size; } if (write_more != 0) { long writeval = TRAP3f (SYS_Fwrite, fileno, ptr, write_more); if (writeval != 0) { free (prev_contents); TRAP1f (SYS_Fclose, fileno); errno = EIO; return -1; } } free (prev_contents); } _MMIX_allocated_filehandle[fileno] = 1; return fileno; }
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