analyze: add compare-versions

The interface, output, and exit status convention are all taken directly from
rpmdev-vercmp and dpkg --compare-versions. The implementation is different
though. See test-string-util for a list of known cases where we compare
strings incompatibly.

The idea is that this string comparison function will be declared as "the"
method to use for boot entry ordering in the specification and similar
uses. Thus it's nice to allow users to compare strings.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2022-05-17 16:28:45 +02:00
parent fddad5f4a6
commit bc012a3e91
5 changed files with 116 additions and 2 deletions

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@ -118,6 +118,14 @@
<arg choice="plain">cat-config</arg>
<arg choice="plain" rep="repeat"><replaceable>NAME</replaceable>|<replaceable>PATH</replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-analyze</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="plain">compare-versions</arg>
<arg choice="plain"><replaceable>VERSION1</replaceable></arg>
<arg choice="opt"><replaceable>OP</replaceable></arg>
<arg choice="plain"><replaceable>VERSION2</replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-analyze</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
@ -547,6 +555,52 @@ NAutoVTs=8
</example>
</refsect2>
<refsect2>
<title><command>systemd-analyze compare-versions
<replaceable>VERSION1</replaceable>
<optional><replaceable>OP</replaceable></optional>
<replaceable>VERSION2</replaceable></command></title>
<para>This command has two distinct modes of operation, depending on whether the operator
<replaceable>OP</replaceable> is specified.</para>
<para>In the first mode — when <replaceable>OP</replaceable> is not specified — it will compare the two
version strings and print either <literal><replaceable>VERSION1</replaceable> &lt;
<replaceable>VERSION2</replaceable></literal>, or <literal><replaceable>VERSION1</replaceable> ==
<replaceable>VERSION2</replaceable></literal>, or <literal><replaceable>VERSION1</replaceable> &gt;
<replaceable>VERSION2</replaceable></literal> as appropriate.</para>
<para>The exit status is <constant>0</constant> if the versions are equal, <constant>11</constant> if
the version of the right is smaller, and <constant>12</constant> if the version of the left is
smaller. (This matches the convention used by <command>rpmdev-vercmp</command>.)</para>
<para>In the second mode — when <replaceable>OP</replaceable> is specified — it will compare the two
version strings using the operation <replaceable>OP</replaceable> and return <constant>0</constant>
(success) if they condition is satisfied, and <constant>1</constant> (failure)
otherwise. <constant>OP</constant> may be <command>lt</command>, <command>le</command>,
<command>eq</command>, <command>ne</command>, <command>ge</command>, <command>gt</command>. In this
mode, no output is printed.
(This matches the convention used by
<citerefentry project='die-net'><refentrytitle>dpkg</refentrytitle><manvolnum>1</manvolnum></citerefentry>
<option>--compare-versions</option>.)</para>
<example>
<title>Compare versions of a package</title>
<programlisting>
$ systemd-analyze compare-versions systemd-250~rc1.fc36.aarch64 systemd-251.fc36.aarch64
systemd-250~rc1.fc36.aarch64 &lt; systemd-251.fc36.aarch64
$ echo $?
12
$ systemd-analyze compare-versions 1 lt 2; echo $?
0
$ systemd-analyze compare-versions 1 ge 2; echo $?
1
</programlisting>
</example>
</refsect2>
<refsect2>
<title><command>systemd-analyze verify <replaceable>FILE</replaceable>...</command></title>
@ -1197,8 +1251,12 @@ $ systemd-analyze verify /tmp/source:alias.service
<refsect1>
<title>Exit status</title>
<para>On success, 0 is returned, a non-zero failure code
otherwise.</para>
<para>For most commands, 0 is returned on success, and a non-zero failure code otherwise.</para>
<para>With the verb <command>compare-versions</command>, in the two-argument form,
<constant>12</constant>, <constant>0</constant>, <constant>11</constant> is returned if the second
version string is respectively larger, equal, or smaller to the first. In the three-argument form,
<constant>0</constant> or <constant>1</constant> if the condition is respectively true or false.</para>
</refsect1>
<xi:include href="common-variables.xml" />

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@ -0,0 +1,47 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <stdio.h>
#include "analyze-compare-versions.h"
#include "macro.h"
#include "string-util.h"
#include "strv.h"
int verb_compare_versions(int argc, char *argv[], void *userdata) {
int r;
assert(argc == 3 || argc == 4);
assert(argv);
if (argc == 3) {
r = strverscmp_improved(ASSERT_PTR(argv[1]), ASSERT_PTR(argv[2]));
printf("%s %s %s\n",
argv[1],
r < 0 ? "<" : r > 0 ? ">" : "==",
argv[2]);
/* This matches the exit convention used by rpmdev-vercmp.
* We don't use named values because 11 and 12 don't have names. */
return r < 0 ? 12 : r > 0 ? 11 : 0;
} else {
const char *op = ASSERT_PTR(argv[2]);
r = strverscmp_improved(ASSERT_PTR(argv[1]), ASSERT_PTR(argv[3]));
if (STR_IN_SET(op, "lt", "<"))
return r < 0 ? EXIT_SUCCESS : EXIT_FAILURE;
if (STR_IN_SET(op, "le", "<="))
return r <= 0 ? EXIT_SUCCESS : EXIT_FAILURE;
if (STR_IN_SET(op, "eq", "=="))
return r == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
if (STR_IN_SET(op, "ne", "!="))
return r != 0 ? EXIT_SUCCESS : EXIT_FAILURE;
if (STR_IN_SET(op, "ge", ">="))
return r >= 0 ? EXIT_SUCCESS : EXIT_FAILURE;
if (STR_IN_SET(op, "gt", ">"))
return r > 0 ? EXIT_SUCCESS : EXIT_FAILURE;
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Unknown operator \"%s\".", op);
}
}

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@ -0,0 +1,3 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
int verb_compare_versions(int argc, char *argv[], void *userdata);

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@ -35,6 +35,7 @@
#include "analyze-timestamp.h"
#include "analyze-unit-files.h"
#include "analyze-unit-paths.h"
#include "analyze-compare-versions.h"
#include "analyze-verify.h"
#include "bus-error.h"
#include "bus-locator.h"
@ -199,6 +200,8 @@ static int help(int argc, char *argv[], void *userdata) {
" syscall-filter [NAME...] List syscalls in seccomp filters\n"
" filesystems [NAME...] List known filesystems\n"
" condition CONDITION... Evaluate conditions and asserts\n"
" compare-versions VERSION1 [OP] VERSION2\n"
" Compare two version strings\n"
" verify FILE... Check unit files for correctness\n"
" calendar SPEC... Validate repetitive calendar time\n"
" events\n"
@ -564,6 +567,7 @@ static int run(int argc, char *argv[]) {
{ "capability", VERB_ANY, VERB_ANY, 0, verb_capabilities },
{ "filesystems", VERB_ANY, VERB_ANY, 0, verb_filesystems },
{ "condition", VERB_ANY, VERB_ANY, 0, verb_condition },
{ "compare-versions", 3, 4, 0, verb_compare_versions },
{ "verify", 2, VERB_ANY, 0, verb_verify },
{ "calendar", 2, VERB_ANY, 0, verb_calendar },
{ "timestamp", 2, VERB_ANY, 0, verb_timestamp },

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@ -9,6 +9,8 @@ systemd_analyze_sources = files(
'analyze-capability.h',
'analyze-cat-config.c',
'analyze-cat-config.h',
'analyze-compare-versions.c',
'analyze-compare-versions.h',
'analyze-condition.c',
'analyze-condition.h',
'analyze-critical-chain.c',