From ab2d7fd8bfb1eafc61953e74757e84ed407b1f21 Mon Sep 17 00:00:00 2001 From: David Oberhollenzer Date: Sun, 15 Sep 2019 17:34:39 +0200 Subject: Add an sqfs_file_t implementation for reading from STDIN Signed-off-by: David Oberhollenzer --- include/sqfs/io.h | 11 +++++ lib/sqfs/Makemodule.am | 2 +- lib/sqfs/io_stdin.c | 115 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 127 insertions(+), 1 deletion(-) create mode 100644 lib/sqfs/io_stdin.c diff --git a/include/sqfs/io.h b/include/sqfs/io.h index 0f980d6..a544875 100644 --- a/include/sqfs/io.h +++ b/include/sqfs/io.h @@ -142,6 +142,17 @@ extern "C" { */ SQFS_API sqfs_file_t *sqfs_open_file(const char *filename, int flags); +/** + * @brief Get a read-only file implementation that represents standard input + * + * This function creates a read-only file that represents STDIN. The file + * supports reading up to a specified number of bytes and only allows + * reading sequentially. + * + * @param size The alleged "size" of the file. + */ +SQFS_API sqfs_file_t *sqfs_get_stdin_file(uint64_t size); + #ifdef __cplusplus } #endif diff --git a/lib/sqfs/Makemodule.am b/lib/sqfs/Makemodule.am index 7199441..b58a28b 100644 --- a/lib/sqfs/Makemodule.am +++ b/lib/sqfs/Makemodule.am @@ -13,7 +13,7 @@ libsquashfs_la_SOURCES += lib/sqfs/read_super.c lib/sqfs/meta_reader.c libsquashfs_la_SOURCES += lib/sqfs/read_inode.c lib/sqfs/write_inode.c libsquashfs_la_SOURCES += lib/sqfs/dir_writer.c lib/sqfs/xattr_reader.c libsquashfs_la_SOURCES += lib/sqfs/read_table.c lib/sqfs/comp/compressor.c -libsquashfs_la_SOURCES += lib/sqfs/comp/internal.h +libsquashfs_la_SOURCES += lib/sqfs/io_stdin.c lib/sqfs/comp/internal.h libsquashfs_la_SOURCES += lib/sqfs/blk_proc/process_block.c libsquashfs_la_SOURCES += lib/sqfs/blk_proc/internal.h libsquashfs_la_CPPFLAGS = $(AM_CPPFLAGS) diff --git a/lib/sqfs/io_stdin.c b/lib/sqfs/io_stdin.c new file mode 100644 index 0000000..a65fa0f --- /dev/null +++ b/lib/sqfs/io_stdin.c @@ -0,0 +1,115 @@ +/* SPDX-License-Identifier: LGPL-3.0-or-later */ +/* + * io_stdin.c + * + * Copyright (C) 2019 David Oberhollenzer + */ +#define SQFS_BUILDING_DLL +#include "config.h" + +#include "sqfs/io.h" +#include "sqfs/error.h" + +#include +#include +#include + + +typedef struct { + sqfs_file_t base; + + uint64_t offset; + uint64_t size; +} sqfs_file_stdin_t; + + +static void stdin_destroy(sqfs_file_t *base) +{ + free(base); +} + +static int stdin_read_at(sqfs_file_t *base, uint64_t offset, + void *buffer, size_t size) +{ + sqfs_file_stdin_t *file = (sqfs_file_stdin_t *)base; + size_t temp_size = 0; + uint8_t *temp = NULL; + uint64_t diff; + ssize_t ret; + + if (offset < file->offset) + return SQFS_ERROR_IO; + + if (offset > file->offset) { + temp_size = 1024; + temp = alloca(temp_size); + } + + if (offset >= file->size || (offset + size) > file->size) + return SQFS_ERROR_OUT_OF_BOUNDS; + + while (size > 0) { + if (offset > file->offset) { + diff = file->offset - offset; + diff = diff > (uint64_t)temp_size ? temp_size : diff; + + ret = read(STDIN_FILENO, temp, diff); + } else { + ret = read(STDIN_FILENO, buffer, size); + } + + if (ret < 0) { + if (errno == EINTR) + continue; + return SQFS_ERROR_IO; + } + + if (ret == 0) + return SQFS_ERROR_OUT_OF_BOUNDS; + + if (offset <= file->offset) { + buffer = (char *)buffer + ret; + size -= ret; + offset += ret; + } + + file->offset += ret; + } + + return 0; +} + +static int stdin_write_at(sqfs_file_t *base, uint64_t offset, + const void *buffer, size_t size) +{ + (void)base; (void)offset; (void)buffer; (void)size; + return SQFS_ERROR_IO; +} + +static uint64_t stdin_get_size(const sqfs_file_t *base) +{ + return ((const sqfs_file_stdin_t *)base)->size; +} + +static int stdin_truncate(sqfs_file_t *base, uint64_t size) +{ + (void)base; (void)size; + return SQFS_ERROR_IO; +} + +sqfs_file_t *sqfs_get_stdin_file(uint64_t size) +{ + sqfs_file_stdin_t *file = calloc(1, sizeof(*file)); + sqfs_file_t *base = (sqfs_file_t *)file; + + if (file == NULL) + return NULL; + + file->size = size; + base->destroy = stdin_destroy; + base->read_at = stdin_read_at; + base->write_at = stdin_write_at; + base->get_size = stdin_get_size; + base->truncate = stdin_truncate; + return base; +} -- cgit v1.2.3