From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: util-linux-owner@vger.kernel.org Received: from mail-ob0-f181.google.com ([209.85.214.181]:43958 "EHLO mail-ob0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751669AbaCHVnj (ORCPT ); Sat, 8 Mar 2014 16:43:39 -0500 Received: by mail-ob0-f181.google.com with SMTP id wp4so5513409obc.40 for ; Sat, 08 Mar 2014 13:43:39 -0800 (PST) From: Sami Kerola To: util-linux@vger.kernel.org Cc: kerolasa@iki.fi Subject: [PATCH 5/5] mcookie: add --max-size option Date: Sat, 8 Mar 2014 15:43:30 -0600 Message-Id: <1394315010-22481-5-git-send-email-kerolasa@iki.fi> In-Reply-To: <1394315010-22481-1-git-send-email-kerolasa@iki.fi> References: <1394315010-22481-1-git-send-email-kerolasa@iki.fi> Sender: util-linux-owner@vger.kernel.org List-ID: Just in case someone wants to add entropy from device with invocation demonstrated below. $ mcookie --file /dev/urandom --max-size 64k Signed-off-by: Sami Kerola --- misc-utils/mcookie.1 | 15 +++++++++++++++ misc-utils/mcookie.c | 29 ++++++++++++++++++++++++----- 2 files changed, 39 insertions(+), 5 deletions(-) diff --git a/misc-utils/mcookie.1 b/misc-utils/mcookie.1 index df6137f..1b6ac76 100644 --- a/misc-utils/mcookie.1 +++ b/misc-utils/mcookie.1 @@ -27,6 +27,21 @@ in this preference order. Use additional file as a macig cookie random seed. When file is defined as '-' character input is read from stdin. .TP +\fB\-m\fR, \fB\-\-max\-size\fR=\fInumber\fR +Read form +.I FILE +only +.I number +of bytes. This option is meant to be used when reading additional +randomness from a device. +.IP +The +.I number +argument may be followed by the multiplicative suffixes KiB=1024, +MiB=1024*1024, and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is +optional, e.g., "K" has the same meaning as "KiB") or the suffixes +KB=1000, MB=1000*1000, and so on for GB, TB, PB, EB, ZB and YB. +.TP \fB\-v\fR, \fB\-\-verbose\fR Inform where randomness originated, with amount of entropy read from each source. diff --git a/misc-utils/mcookie.c b/misc-utils/mcookie.c index 31f33e4..caa1b8f 100644 --- a/misc-utils/mcookie.c +++ b/misc-utils/mcookie.c @@ -23,6 +23,7 @@ #include "nls.h" #include "closestream.h" #include "randutils.h" +#include "strutils.h" #include "xalloc.h" #include @@ -43,6 +44,7 @@ struct mcookie_control { char **files; int nfiles; int fd; + uint64_t maxsz; unsigned int verbose:1; }; @@ -50,11 +52,22 @@ struct mcookie_control { /* The basic function to hash a file */ static size_t hash_file(struct mcookie_control *ctl) { - size_t count = 0; - ssize_t r; + size_t count = 0, read_sz; + ssize_t r = 1; unsigned char buf[BUFFERSIZE]; - - while ((r = read(ctl->fd, buf, sizeof(buf))) > 0) { + int stop = 0; + + read_sz = sizeof(buf); + while (!stop) { + if (ctl->maxsz) { + if (ctl->maxsz <= read_sz) { + read_sz = ctl->maxsz; + stop = 1; + } else + ctl->maxsz -= read_sz; + } + if ((r = read(ctl->fd, buf, read_sz)) == 0) + break; MD5Update(&(ctl->ctx), buf, r); count += r; } @@ -70,6 +83,7 @@ static void __attribute__((__noreturn__)) usage(FILE * out) fprintf(out, _(" %s [options]\n"), program_invocation_short_name); fputs(USAGE_OPTIONS, out); fputs(_(" -f, --file use file as a cookie seed\n"), out); + fputs(_(" -m, --max-size limit how much is read from seed files\n"), out); fputs(_(" -v, --verbose explain what is being done\n"), out); fputs(USAGE_SEPARATOR, out); fputs(USAGE_HELP, out); @@ -117,6 +131,7 @@ int main(int argc, char **argv) static const struct option longopts[] = { {"file", required_argument, NULL, 'f'}, + {"max-size", required_argument, NULL, 'm'}, {"verbose", no_argument, NULL, 'v'}, {"version", no_argument, NULL, 'V'}, {"help", no_argument, NULL, 'h'}, @@ -135,7 +150,7 @@ int main(int argc, char **argv) ctl.files = xmalloc(sizeof(char *) * argc); while ((c = - getopt_long(argc, argv, "f:vVh", longopts, NULL)) != -1) + getopt_long(argc, argv, "f:m:vVh", longopts, NULL)) != -1) switch (c) { case 'v': ctl.verbose = 1; @@ -144,6 +159,10 @@ int main(int argc, char **argv) ctl.files[ctl.nfiles] = optarg; ctl.nfiles++; break; + case 'm': + ctl.maxsz = strtosize_or_err(optarg, + _("failed to parse length")); + break; case 'V': printf(UTIL_LINUX_VERSION); return EXIT_SUCCESS; -- 1.9.0