diff options
Diffstat (limited to 'programs/cmd_dump_metadata.c')
| -rw-r--r-- | programs/cmd_dump_metadata.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/programs/cmd_dump_metadata.c b/programs/cmd_dump_metadata.c new file mode 100644 index 0000000..94cc8ec --- /dev/null +++ b/programs/cmd_dump_metadata.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: MIT +/* + * The 'fsverity dump_metadata' command + * + * Copyright 2021 Google LLC + * + * Use of this source code is governed by an MIT-style + * license that can be found in the LICENSE file or at + * https://opensource.org/licenses/MIT. + */ + +#include "fsverity.h" + +#include <fcntl.h> +#include <getopt.h> +#include <sys/ioctl.h> +#include <unistd.h> + +static const struct option longopts[] = { + {"offset", required_argument, NULL, OPT_OFFSET}, + {"length", required_argument, NULL, OPT_LENGTH}, + {NULL, 0, NULL, 0} +}; + +static const struct { + const char *name; + int val; +} metadata_types[] = { + {"merkle_tree", FS_VERITY_METADATA_TYPE_MERKLE_TREE}, + {"descriptor", FS_VERITY_METADATA_TYPE_DESCRIPTOR}, + {"signature", FS_VERITY_METADATA_TYPE_SIGNATURE}, +}; + +static bool parse_metadata_type(const char *name, __u64 *val_ret) +{ + size_t i; + + for (i = 0; i < ARRAY_SIZE(metadata_types); i++) { + if (strcmp(name, metadata_types[i].name) == 0) { + *val_ret = metadata_types[i].val; + return true; + } + } + error_msg("unknown metadata type: %s", name); + fputs(" Expected", stderr); + for (i = 0; i < ARRAY_SIZE(metadata_types); i++) { + if (i != 0 && ARRAY_SIZE(metadata_types) > 2) + putc(',', stderr); + putc(' ', stderr); + if (i != 0 && i == ARRAY_SIZE(metadata_types) - 1) + fputs("or ", stderr); + fprintf(stderr, "\"%s\"", metadata_types[i].name); + } + fprintf(stderr, "\n"); + return false; +} + +/* Dump the fs-verity metadata of the given file. */ +int fsverity_cmd_dump_metadata(const struct fsverity_command *cmd, + int argc, char *argv[]) +{ + bool offset_specified = false; + bool length_specified = false; + struct filedes file = { .fd = -1 }; + struct filedes stdout_filedes = { .fd = STDOUT_FILENO, + .name = "stdout" }; + struct fsverity_read_metadata_arg arg = { .length = 32768 }; + void *buf = NULL; + char *tmp; + int c; + int status; + int bytes_read; + + while ((c = getopt_long(argc, argv, "", longopts, NULL)) != -1) { + switch (c) { + case OPT_OFFSET: + if (offset_specified) { + error_msg("--offset can only be specified once"); + goto out_usage; + } + errno = 0; + arg.offset = strtoull(optarg, &tmp, 10); + if (errno || *tmp) { + error_msg("invalid value for --offset"); + goto out_usage; + } + offset_specified = true; + break; + case OPT_LENGTH: + if (length_specified) { + error_msg("--length can only be specified once"); + goto out_usage; + } + errno = 0; + arg.length = strtoull(optarg, &tmp, 10); + if (errno || *tmp || arg.length > SIZE_MAX) { + error_msg("invalid value for --length"); + goto out_usage; + } + length_specified = true; + break; + default: + goto out_usage; + } + } + + argv += optind; + argc -= optind; + + if (argc != 2) + goto out_usage; + + if (!parse_metadata_type(argv[0], &arg.metadata_type)) + goto out_usage; + + if (length_specified && !offset_specified) { + error_msg("--length specified without --offset"); + goto out_usage; + } + if (offset_specified && !length_specified) { + error_msg("--offset specified without --length"); + goto out_usage; + } + + buf = xzalloc(arg.length); + arg.buf_ptr = (uintptr_t)buf; + + if (!open_file(&file, argv[1], O_RDONLY, 0)) + goto out_err; + + /* + * If --offset and --length were specified, then do only the single read + * requested. Otherwise read until EOF. + */ + do { + bytes_read = ioctl(file.fd, FS_IOC_READ_VERITY_METADATA, &arg); + if (bytes_read < 0) { + error_msg_errno("FS_IOC_READ_VERITY_METADATA failed on '%s'", + file.name); + goto out_err; + } + if (bytes_read == 0) + break; + if (!full_write(&stdout_filedes, buf, bytes_read)) + goto out_err; + arg.offset += bytes_read; + } while (!length_specified); + + status = 0; +out: + free(buf); + filedes_close(&file); + return status; + +out_err: + status = 1; + goto out; + +out_usage: + usage(cmd, stderr); + status = 2; + goto out; +} |