/* * Copyright (c) 2017 Kungliga Tekniska Högskolan * (Royal Institute of Technology, Stockholm, Sweden). * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * 3. Neither the name of the Institute nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include "krb5_locl.h" #include "store-int.h" #ifndef HAVE_FSEEKO #define fseeko fseek #define ftello ftell #endif typedef struct stdio_storage { FILE *f; off_t pos; } stdio_storage; #define F(S) (((stdio_storage*)(S)->data)->f) #define POS(S) (((stdio_storage*)(S)->data)->pos) static ssize_t stdio_fetch(krb5_storage * sp, void *data, size_t size) { char *cbuf = (char *)data; ssize_t count; size_t rem = size; /* similar pattern to net_read() to support pipes */ while (rem > 0) { count = fread(cbuf, 1, rem, F(sp)); if (count < 0) { POS(sp) = -1; if (errno == EINTR) continue; else return count; } else if (count == 0) { if (POS(sp) >= 0) POS(sp) += size - rem; return size - rem; } cbuf += count; rem -= count; } if (POS(sp) >= 0) POS(sp) += size; return size; } static ssize_t stdio_store(krb5_storage * sp, const void *data, size_t size) { const char *cbuf = (const char *)data; ssize_t count; size_t rem = size; /* * It's possible we just went from reading to writing if the file was open * for both. Per C99 (N869 final draft) section 7.18.5.3, point 6, when * going from reading to writing [a file opened for both] one must seek. */ (void) fseeko(F(sp), 0, SEEK_CUR); /* similar pattern to net_write() to support pipes */ while (rem > 0) { count = fwrite(cbuf, 1, rem, F(sp)); if (count < 0) { if (errno == EINTR) continue; /* * What does it mean to have a short write when using stdio? * * It can't mean much. After all stdio is buffering, so * earlier writes that appeared complete may have failed, * and so we don't know how much we really failed to write. */ POS(sp) = -1; return -1; } if (count == 0) { POS(sp) = -1; return -1; } cbuf += count; rem -= count; } if (POS(sp) >= 0) POS(sp) += size; return size; } static off_t stdio_seek(krb5_storage * sp, off_t offset, int whence) { int save_errno = errno; if (whence == SEEK_SET && POS(sp) == offset) return POS(sp); if (whence == SEEK_CUR && POS(sp) >= 0 && offset == 0) return POS(sp); if (fseeko(F(sp), offset, whence) != 0) return -1; errno = save_errno; return POS(sp) = ftello(F(sp)); } static int stdio_trunc(krb5_storage * sp, off_t offset) { off_t tmpoff; int save_errno = errno; if (fflush(F(sp)) == EOF) return errno; tmpoff = ftello(F(sp)); if (tmpoff < 0) return errno; if (tmpoff > offset) tmpoff = offset; if (ftruncate(fileno(F(sp)), offset) == -1) return errno; if (fseeko(F(sp), 0, SEEK_END) == -1) return errno; if (fseeko(F(sp), tmpoff, SEEK_SET) == -1) return errno; errno = save_errno; POS(sp) = tmpoff; return 0; } static int stdio_sync(krb5_storage * sp) { if (fflush(F(sp)) == EOF) return errno; if (fsync(fileno(F(sp))) == -1) return errno; return 0; } static void stdio_free(krb5_storage * sp) { int save_errno = errno; if (F(sp) != NULL && fclose(F(sp)) == 0) errno = save_errno; F(sp) = NULL; } /** * Open a krb5_storage using stdio for buffering. * * @return A krb5_storage on success, or NULL on out of memory error. * * @ingroup krb5_storage * * @sa krb5_storage_emem() * @sa krb5_storage_from_fd() * @sa krb5_storage_from_mem() * @sa krb5_storage_from_readonly_mem() * @sa krb5_storage_from_data() * @sa krb5_storage_from_socket() */ KRB5_LIB_FUNCTION krb5_storage * KRB5_LIB_CALL krb5_storage_stdio_from_fd(int fd_in, const char *mode) { krb5_storage *sp; off_t off; FILE *f; int saved_errno = errno; int fd; off = lseek(fd_in, 0, SEEK_CUR); if (off == -1) return NULL; #ifdef _MSC_VER /* * This function used to try to pass the input to * _get_osfhandle() to test if the value is a HANDLE * but this doesn't work because doing so throws an * exception that will result in Watson being triggered * to file a Windows Error Report. */ fd = _dup(fd_in); #else fd = dup(fd_in); #endif if (fd < 0) return NULL; f = fdopen(fd, mode); if (f == NULL) { (void) close(fd); return NULL; } errno = saved_errno; if (fseeko(f, off, SEEK_SET) == -1) { saved_errno = errno; (void) fclose(f); errno = saved_errno; return NULL; } errno = ENOMEM; sp = malloc(sizeof(krb5_storage)); if (sp == NULL) { saved_errno = errno; (void) fclose(f); errno = saved_errno; return NULL; } errno = ENOMEM; sp->data = malloc(sizeof(stdio_storage)); if (sp->data == NULL) { saved_errno = errno; (void) fclose(f); free(sp); errno = saved_errno; return NULL; } sp->flags = 0; sp->eof_code = HEIM_ERR_EOF; F(sp) = f; POS(sp) = off; sp->fetch = stdio_fetch; sp->store = stdio_store; sp->seek = stdio_seek; sp->trunc = stdio_trunc; sp->fsync = stdio_sync; sp->free = stdio_free; sp->max_alloc = UINT32_MAX/64; return sp; }