utils-std

sha256sum.c (5794B)

// utils-std: Collection of commonly available Unix tools
// SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
// SPDX-License-Identifier: MPL-2.0
#define _POSIX_C_SOURCE 200809L
#include "../lib/getopt_nolong.h"
#include "../lib/sha256.h"  // sha256_*
#include "../lib/strconv.h" // bytes2hex
#include <ctype.h> // isxdigit
#include <errno.h>
#include <fcntl.h> // open, O_*
#include <stdbool.h>
#include <stdio.h>  // fprintf
#include <stdlib.h> // free
#include <string.h> // strerror
#include <unistd.h> // read, write, close, getopt
#define SHA256SUM_LEN SHA256_DIGEST_LENGTH * 2 + 1
const char *argv0 = "sha256sum";
static int
sha256sum(int fd, const char *fdname, char sum[SHA256SUM_LEN])
{
	struct sha256 ctx;
	sha256_init(&ctx);
	uint8_t buf[BUFSIZ];
	ssize_t nread = -1;
	while((nread = read(fd, buf, BUFSIZ)) > 0)
	{
		sha256_update(&ctx, buf, nread);
	}
	if(nread < 0)
	{
		fprintf(stderr,
		        "%s: error: Failed reading file '%s': %s\n",
		        argv0,
		        fdname ? fdname : "<stdin>",
		        strerror(errno));
		return -1;
	}
	uint8_t res[SHA256_DIGEST_LENGTH] = "";
	sha256_sum(&ctx, res);
	bytes2hex(res, SHA256_DIGEST_LENGTH, sum, SHA256SUM_LEN);
	return 0;
}
#define STR(s) #s
#define XSTR(s) STR(s)
static int
check(FILE *file, const char *filename)
{
	int err = 0;
	ssize_t nread = -1;
	char *line = NULL;
	size_t len = 0;
	errno = 0;
	while((nread = getline(&line, &len, file)) > 0)
	{
		if(line[nread - 1] == '\n') line[nread - 1] = '\0';
		ssize_t i = 0;
		for(; i < nread; i++)
		{
			if(isxdigit(line[i])) continue;
			if(line[i] == ' ')
			{
				line[i] = '\0';
				break;
			}
			fprintf(stderr,
			        "%s: error: Invalid character '%c' while reading hash in line: %s\n",
			        argv0,
			        line[i],
			        line);
			if(len > 0) free(line);
			return -1;
		}
		if(line[i++] != '\0')
		{
			fprintf(stderr, "%s: error: Invalid line: %s\n", argv0, line);
			if(len > 0) free(line);
			return -1;
		}
		if(i != SHA256SUM_LEN)
		{
			fprintf(stderr,
			        "%s: error: Got %zd hexadecimal digits while expected %d for a SHA256\n",
			        argv0,
			        i,
			        SHA256SUM_LEN);
			if(len > 0) free(line);
			return -1;
		}
		while(i < nread && line[i] == ' ')
			i++;
		if(i < nread && line[i] == '*') i++;
		char *target = line + i;
		int fd = open(target, O_RDONLY | O_NOCTTY);
		if(fd < 0)
		{
			fprintf(stderr, "%s: error: Failed opening file '%s': %s\n", argv0, target, strerror(errno));
			if(len > 0) free(line);
			return -1;
		}
		int ret = posix_fadvise(fd, 0, 0, POSIX_FADV_SEQUENTIAL);
		if(ret != 0)
			fprintf(stderr,
			        "%s: warning: posix_fadvise failed on file '%s': %s\n",
			        argv0,
			        target,
			        strerror(ret));
		char got[SHA256SUM_LEN] = "";
		if(sha256sum(fd, target, got) < 0) err = 1;
		if(memcmp(line, got, SHA256SUM_LEN) == 0)
		{
			printf("%s: OK\n", target);
		}
		else
		{
			err = 1;
			printf("%s: FAILED\n", target);
		}
		if(close(fd) < 0)
		{
			fprintf(
			    stderr, "%s: error: Failed closing file '%s': %s\n", argv0, filename, strerror(errno));
			if(len > 0) free(line);
			return -1;
		}
	}
	if(nread < 0 && errno != 0)
	{
		err = 1;
		fprintf(stderr,
		        "%s: error: Failed reading line from file '%s': %s\n",
		        argv0,
		        filename,
		        strerror(errno));
	}
	if(len > 0) free(line);
	return err;
}
int
main(int argc, char *argv[])
{
	bool opt_c = false;
	for(int c = -1; (c = getopt_nolong(argc, argv, ":c")) != -1;)
	{
		switch(c)
		{
		case 'c':
			opt_c = true;
			break;
		case ':':
			fprintf(stderr, "%s: error: Missing operand for option: '-%c'\n", argv0, optopt);
			return 1;
		case '?':
			if(!got_long_opt) fprintf(stderr, "%s: error: Unrecognised option: '-%c'\n", argv0, optopt);
			return 1;
		default:
			abort();
		}
	}
	argc -= optind;
	argv += optind;
	if(opt_c)
	{
		if(argc == 0)
		{
			if(check(stdin, "<stdin>") != 0) return 1;
			return 0;
		}
		int err = 0;
		for(int i = 0; i < argc; i++)
		{
			FILE *file = NULL;
			const char *filename = argv[i];
			if(filename[0] == '-' && filename[1] == '\0')
			{
				filename = "<stdin>";
				file = stdin;
			}
			else
			{
				file = fopen(filename, "rb");
				if(file == NULL)
				{
					fprintf(stderr,
					        "%s: error: Failed opening file '%s': %s\n",
					        argv0,
					        filename,
					        strerror(errno));
					return 1;
				}
			}
			if(check(file, filename) != 0) err = 1;
			if(fclose(file) < 0)
			{
				fprintf(
				    stderr, "%s: error: Failed closing file '%s': %s\n", argv0, filename, strerror(errno));
				return 1;
			}
		}
		return err;
	}
	if(argc == 0)
	{
		char sum[SHA256SUM_LEN] = "";
		if(sha256sum(STDIN_FILENO, NULL, sum) < 0) return 1;
		puts(sum);
		return 0;
	}
	for(int i = 0; i < argc; i++)
	{
		int fd = -1;
		const char *filename = argv[i];
		if(filename[0] == '-' && filename[1] == '\0')
		{
			filename = "<stdin>";
			fd = STDIN_FILENO;
		}
		else
		{
			fd = open(filename, O_RDONLY | O_NOCTTY);
			if(fd < 0)
			{
				fprintf(
				    stderr, "%s: error: Failed opening file '%s': %s\n", argv0, filename, strerror(errno));
				return 1;
			}
			int ret = posix_fadvise(fd, 0, 0, POSIX_FADV_SEQUENTIAL);
			if(ret != 0)
				fprintf(stderr,
				        "%s: warning: posix_fadvise failed on file '%s': %s\n",
				        argv0,
				        filename,
				        strerror(ret));
		}
		int err = 0;
		char sum[SHA256SUM_LEN] = "";
		if(sha256sum(fd, filename, sum) < 0) err = 1;
		printf("%s  %s\n", sum, filename);
		if(close(fd) < 0)
		{
			fprintf(
			    stderr, "%s: error: Failed closing file '%s': %s\n", argv0, filename, strerror(errno));
			return 1;
		}
		if(err == 1) return 1;
	}
	return 0;
}