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/*- |
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* Copyright (C) 2013 Pietro Cerutti <gahr@FreeBSD.org> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* |
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* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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*/ |
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|
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#include <sys/cdefs.h> |
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__FBSDID("$FreeBSD: head/lib/libc/stdio/fmemopen.c 266971 2014-06-02 13:48:57Z gahr $"); |
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|
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#include <fcntl.h> |
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#include <stdbool.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <errno.h> |
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// #include "local.h" |
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|
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struct fmemopen_cookie |
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{ |
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char *buf; /* pointer to the memory region */ |
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bool own; /* did we allocate the buffer ourselves? */ |
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char bin; /* is this a binary buffer? */ |
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size_t size; /* buffer length in bytes */ |
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size_t len; /* data length in bytes */ |
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size_t off; /* current offset into the buffer */ |
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}; |
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|
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static int fmemopen_read(void *cookie, char *buf, int nbytes); |
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static int fmemopen_write(void *cookie, const char *buf, int nbytes); |
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static fpos_t fmemopen_seek(void *cookie, fpos_t offset, int whence); |
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static int fmemopen_close(void *cookie); |
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|
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FILE * |
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fmemopen(void * __restrict buf, size_t size, const char * __restrict mode) |
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{ |
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struct fmemopen_cookie *ck; |
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FILE *f; |
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int flags, rc; |
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|
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/* |
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* POSIX says we shall return EINVAL if size is 0. |
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*/ |
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if (size == 0) { |
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errno = EINVAL; |
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return (NULL); |
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} |
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|
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/* |
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* Retrieve the flags as used by open(2) from the mode argument, and |
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* validate them. |
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*/ |
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rc = __sflags(mode, &flags); |
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if (rc == 0) { |
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errno = EINVAL; |
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return (NULL); |
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} |
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|
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/* |
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* There's no point in requiring an automatically allocated buffer |
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* in write-only mode. |
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*/ |
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if (!(flags & O_RDWR) && buf == NULL) { |
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errno = EINVAL; |
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return (NULL); |
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} |
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|
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ck = malloc(sizeof(struct fmemopen_cookie)); |
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if (ck == NULL) { |
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return (NULL); |
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} |
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|
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ck->off = 0; |
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ck->size = size; |
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|
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/* Check whether we have to allocate the buffer ourselves. */ |
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ck->own = ((ck->buf = buf) == NULL); |
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if (ck->own) { |
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ck->buf = malloc(size); |
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if (ck->buf == NULL) { |
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free(ck); |
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return (NULL); |
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} |
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} |
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|
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/* |
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* POSIX distinguishes between w+ and r+, in that w+ is supposed to |
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* truncate the buffer. |
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*/ |
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if (ck->own || mode[0] == 'w') { |
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ck->buf[0] = '\0'; |
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} |
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|
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/* Check for binary mode. */ |
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ck->bin = strchr(mode, 'b') != NULL; |
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|
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/* |
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* The size of the current buffer contents is set depending on the |
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* mode: |
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* |
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* for append (text-mode), the position of the first NULL byte, or the |
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* size of the buffer if none is found |
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* |
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* for append (binary-mode), the size of the buffer |
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* |
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* for read, the size of the buffer |
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* |
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* for write, 0 |
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*/ |
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switch (mode[0]) { |
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case 'a': |
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ck->off = ck->len = strnlen(ck->buf, ck->size); |
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break; |
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case 'r': |
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ck->len = size; |
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break; |
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case 'w': |
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ck->len = 0; |
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break; |
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} |
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|
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f = funopen(ck, |
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flags & O_WRONLY ? NULL : fmemopen_read, |
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flags & O_RDONLY ? NULL : fmemopen_write, |
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fmemopen_seek, fmemopen_close); |
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|
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if (f == NULL) { |
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if (ck->own) |
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free(ck->buf); |
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free(ck); |
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return (NULL); |
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} |
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|
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/* |
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* Turn off buffering, so a write past the end of the buffer |
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* correctly returns a short object count. |
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*/ |
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setvbuf(f, NULL, _IONBF, 0); |
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|
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return (f); |
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} |
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|
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static int |
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fmemopen_read(void *cookie, char *buf, int nbytes) |
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{ |
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struct fmemopen_cookie *ck = cookie; |
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|
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if (nbytes > ck->len - ck->off) |
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nbytes = ck->len - ck->off; |
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|
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if (nbytes == 0) |
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return (0); |
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|
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memcpy(buf, ck->buf + ck->off, nbytes); |
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|
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ck->off += nbytes; |
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|
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return (nbytes); |
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} |
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|
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static int |
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fmemopen_write(void *cookie, const char *buf, int nbytes) |
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{ |
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struct fmemopen_cookie *ck = cookie; |
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|
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if (nbytes > ck->size - ck->off) |
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nbytes = ck->size - ck->off; |
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|
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if (nbytes == 0) |
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return (0); |
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|
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memcpy(ck->buf + ck->off, buf, nbytes); |
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|
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ck->off += nbytes; |
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|
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if (ck->off > ck->len) |
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ck->len = ck->off; |
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|
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/* |
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* We append a NULL byte if all these conditions are met: |
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* - the buffer is not binary |
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* - the buffer is not full |
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* - the data just written doesn't already end with a NULL byte |
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*/ |
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if (!ck->bin && ck->off < ck->size && ck->buf[ck->off - 1] != '\0') |
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ck->buf[ck->off] = '\0'; |
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|
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return (nbytes); |
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} |
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|
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static fpos_t |
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fmemopen_seek(void *cookie, fpos_t offset, int whence) |
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{ |
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struct fmemopen_cookie *ck = cookie; |
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|
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|
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switch (whence) { |
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case SEEK_SET: |
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if (offset > ck->size) { |
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errno = EINVAL; |
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return (-1); |
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} |
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ck->off = offset; |
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break; |
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|
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case SEEK_CUR: |
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if (ck->off + offset > ck->size) { |
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errno = EINVAL; |
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return (-1); |
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} |
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ck->off += offset; |
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break; |
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|
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case SEEK_END: |
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if (offset > 0 || -offset > ck->len) { |
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errno = EINVAL; |
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return (-1); |
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} |
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ck->off = ck->len + offset; |
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break; |
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|
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default: |
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errno = EINVAL; |
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return (-1); |
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} |
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|
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return (ck->off); |
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} |
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|
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static int |
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fmemopen_close(void *cookie) |
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{ |
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struct fmemopen_cookie *ck = cookie; |
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|
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if (ck->own) |
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free(ck->buf); |
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|
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free(ck); |
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|
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return (0); |
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} |