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sysext: rework command line interface to be verb-based

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As suggested by @yuwata:

https://github.com/systemd/systemd/pull/18181#pullrequestreview-570826113
This commit is contained in:
Lennart Poettering 2021-01-19 19:57:56 +01:00
parent 9901835d80
commit 8662fcbcf1
2 changed files with 163 additions and 166 deletions
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325
src/sysext/sysext.c
View File

@ -29,14 +29,8 @@
#include "stat-util.h"
#include "terminal-util.h"
#include "user-util.h"
#include "verbs.h"
static enum {
ACTION_STATUS,
ACTION_MERGE,
ACTION_UNMERGE,
ACTION_REFRESH,
ACTION_LIST,
} arg_action = ACTION_STATUS;
static char **arg_hierarchies = NULL; /* "/usr" + "/opt" by default */
static char *arg_root = NULL;
static JsonFormatFlags arg_json_format_flags = JSON_FORMAT_OFF;
@ -149,7 +143,15 @@ static int unmerge(void) {
return ret;
}
static int status(void) {
static int verb_unmerge(int argc, char **argv, void *userdata) {
if (!have_effective_cap(CAP_SYS_ADMIN))
return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged.");
return unmerge();
}
static int verb_status(int argc, char **argv, void *userdata) {
_cleanup_(table_unrefp) Table *t = NULL;
int r, ret = 0;
char **p;
@ -735,7 +737,134 @@ static int merge(Hashmap *images) {
return r != 123; /* exit code 123 means: didn't do anything */
}
static int help(void) {
static int verb_merge(int argc, char **argv, void *userdata) {
_cleanup_(hashmap_freep) Hashmap *images = NULL;
char **p;
int r;
if (!have_effective_cap(CAP_SYS_ADMIN))
return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged.");
images = hashmap_new(&image_hash_ops);
if (!images)
return log_oom();
r = image_discover(IMAGE_EXTENSION, arg_root, images);
if (r < 0)
return log_error_errno(r, "Failed to discover extension images: %m");
/* In merge mode fail if things are already merged. (In --refresh mode below we'll unmerge if we find
* things are already merged...) */
STRV_FOREACH(p, arg_hierarchies) {
_cleanup_free_ char *resolved = NULL;
r = chase_symlinks(*p, arg_root, CHASE_PREFIX_ROOT, &resolved, NULL);
if (r == -ENOENT) {
log_debug_errno(r, "Hierarchy '%s%s' does not exist, ignoring.", strempty(arg_root), *p);
continue;
}
if (r < 0)
return log_error_errno(r, "Failed to resolve path to hierarchy '%s%s': %m", strempty(arg_root), *p);
r = is_our_mount_point(resolved);
if (r < 0)
return r;
if (r > 0)
return log_error_errno(SYNTHETIC_ERRNO(EBUSY),
"Hierarchy '%s' is already merged.", *p);
}
return merge(images);
}
static int verb_refresh(int argc, char **argv, void *userdata) {
_cleanup_(hashmap_freep) Hashmap *images = NULL;
int r;
if (!have_effective_cap(CAP_SYS_ADMIN))
return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged.");
images = hashmap_new(&image_hash_ops);
if (!images)
return log_oom();
r = image_discover(IMAGE_EXTENSION, arg_root, images);
if (r < 0)
return log_error_errno(r, "Failed to discover extension images: %m");
r = merge(images); /* Returns > 0 if it did something, i.e. a new overlayfs is mounted now. When it
* does so it implicitly unmounts any overlayfs placed there before. Returns == 0
* if it did nothing, i.e. no extension images found. In this case the old
* overlayfs remains in place if there was one. */
if (r < 0)
return r;
if (r == 0) /* No images found? Then unmerge. The goal of --refresh is after all that after having
* called there's a guarantee that the merge status matches the installed extensions. */
r = unmerge();
/* Net result here is that:
*
* 1. If an overlayfs was mounted before and no extensions exist anymore, we'll have unmerged things.
*
* 2. If an overlayfs was mounted before, and there are still extensions installed' we'll have
* unmerged and then merged things again.
*
* 3. If an overlayfs so far wasn't mounted, and there are extensions installed, we'll have it
* mounted now.
*
* 4. If there was no overlayfs mount so far, and no extensions installed, we implement a NOP.
*/
return 0;
}
static int verb_list(int argc, char **argv, void *userdata) {
_cleanup_(hashmap_freep) Hashmap *images = NULL;
_cleanup_(table_unrefp) Table *t = NULL;
Image *img;
int r;
images = hashmap_new(&image_hash_ops);
if (!images)
return log_oom();
r = image_discover(IMAGE_EXTENSION, arg_root, images);
if (r < 0)
return log_error_errno(r, "Failed to discover extension images: %m");
if ((arg_json_format_flags & JSON_FORMAT_OFF) && hashmap_isempty(images)) {
log_info("No OS extensions found.");
return 0;
}
t = table_new("name", "type", "path", "time");
if (!t)
return log_oom();
HASHMAP_FOREACH(img, images) {
r = table_add_many(
t,
TABLE_STRING, img->name,
TABLE_STRING, image_type_to_string(img->type),
TABLE_PATH, img->path,
TABLE_TIMESTAMP, img->mtime != 0 ? img->mtime : img->crtime);
if (r < 0)
return table_log_add_error(r);
}
(void) table_set_sort(t, (size_t) 0, (size_t) -1);
if (arg_json_format_flags & (JSON_FORMAT_OFF|JSON_FORMAT_PRETTY|JSON_FORMAT_PRETTY_AUTO))
(void) pager_open(arg_pager_flags);
r = table_print_json(t, stdout, arg_json_format_flags);
if (r < 0)
return table_log_print_error(r);
return 0;
}
static int verb_help(int argc, char **argv, void *userdata) {
_cleanup_free_ char *link = NULL;
int r;
@ -746,12 +875,13 @@ static int help(void) {
printf("%1$s [OPTIONS...] [DEVICE]\n"
"\n%5$sMerge extension images into /usr/ and /opt/ hierarchies.%6$s\n"
"\n%3$sCommands:%4$s\n"
" status Show current merge status (default)\n"
" merge Merge extensions into /usr/ and /opt/\n"
" unmerge Unmerge extensions from /usr/ and /opt/\n"
" refresh Unmerge/merge extensions again\n"
" list List installed extensions\n"
" -h --help Show this help\n"
" --version Show package version\n"
" -m --merge Merge extensions into /usr/ and /opt/\n"
" -u --unmerge Unmerge extensions from /usr/ and /opt/\n"
" -R --refresh Unmerge/merge extensions again\n"
" -l --list List all OS images\n"
"\n%3$sOptions:%4$s\n"
" --no-pager Do not pipe output into a pager\n"
" --root=PATH Operate relative to root path\n"
@ -772,10 +902,6 @@ static int parse_argv(int argc, char *argv[]) {
enum {
ARG_VERSION = 0x100,
ARG_NO_PAGER,
ARG_MERGE,
ARG_UNMERGE,
ARG_REFRESH,
ARG_LIST,
ARG_ROOT,
ARG_JSON,
};
@ -785,10 +911,6 @@ static int parse_argv(int argc, char *argv[]) {
{ "version", no_argument, NULL, ARG_VERSION },
{ "no-pager", no_argument, NULL, ARG_NO_PAGER },
{ "root", required_argument, NULL, ARG_ROOT },
{ "merge", no_argument, NULL, 'm' },
{ "unmerge", no_argument, NULL, 'u' },
{ "refresh", no_argument, NULL, 'R' },
{ "list", no_argument, NULL, 'l' },
{ "json", required_argument, NULL, ARG_JSON },
{}
};
@ -798,12 +920,12 @@ static int parse_argv(int argc, char *argv[]) {
assert(argc >= 0);
assert(argv);
while ((c = getopt_long(argc, argv, "hmuRl", options, NULL)) >= 0)
while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
switch (c) {
case 'h':
return help();
return verb_help(argc, argv, NULL);
case ARG_VERSION:
return version();
@ -812,22 +934,6 @@ static int parse_argv(int argc, char *argv[]) {
arg_pager_flags |= PAGER_DISABLE;
break;
case 'm':
arg_action = ACTION_MERGE;
break;
case 'u':
arg_action = ACTION_UNMERGE;
break;
case 'R':
arg_action = ACTION_REFRESH;
break;
case 'l':
arg_action = ACTION_LIST;
break;
case ARG_ROOT:
r = parse_path_argument_and_warn(optarg, false, &arg_root);
if (r < 0)
@ -848,10 +954,6 @@ static int parse_argv(int argc, char *argv[]) {
assert_not_reached("Unhandled option");
}
if (argc - optind > 0)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Unexpected argument.");
return 1;
}
@ -895,8 +997,22 @@ static int parse_env(void) {
return 0;
}
static int sysext_main(int argc, char *argv[]) {
static const Verb verbs[] = {
{ "status", VERB_ANY, 1, VERB_DEFAULT, verb_status },
{ "merge", VERB_ANY, 1, 0, verb_merge },
{ "unmerge", VERB_ANY, 1, 0, verb_unmerge },
{ "refresh", VERB_ANY, 1, 0, verb_refresh },
{ "list", VERB_ANY, 1, 0, verb_list },
{ "help", VERB_ANY, 1, 0, verb_help },
{}
};
return dispatch_verb(argc, argv, verbs, NULL);
}
static int run(int argc, char *argv[]) {
_cleanup_(hashmap_freep) Hashmap *images = NULL;
int r;
log_setup_cli();
@ -915,126 +1031,7 @@ static int run(int argc, char *argv[]) {
return log_oom();
}
/* Given that things deep down in the child process will fail, let's catch the no-privilege issue
* early on */
if (!IN_SET(arg_action, ACTION_STATUS, ACTION_LIST) && !have_effective_cap(CAP_SYS_ADMIN))
return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged.");
if (arg_action == ACTION_STATUS)
return status();
if (arg_action == ACTION_UNMERGE)
return unmerge();
images = hashmap_new(&image_hash_ops);
if (!images)
return log_oom();
r = image_discover(IMAGE_EXTENSION, arg_root, images);
if (r < 0)
return log_error_errno(r, "Failed to discover extension images: %m");
switch (arg_action) {
case ACTION_LIST: {
_cleanup_(table_unrefp) Table *t = NULL;
Image *img;
if ((arg_json_format_flags & JSON_FORMAT_OFF) && hashmap_isempty(images)) {
log_info("No OS extensions found.");
return 0;
}
t = table_new("name", "type", "path", "time");
if (!t)
return log_oom();
HASHMAP_FOREACH(img, images) {
r = table_add_many(
t,
TABLE_STRING, img->name,
TABLE_STRING, image_type_to_string(img->type),
TABLE_PATH, img->path,
TABLE_TIMESTAMP, img->mtime != 0 ? img->mtime : img->crtime);
if (r < 0)
return table_log_add_error(r);
}
(void) table_set_sort(t, (size_t) 0, (size_t) -1);
if (arg_json_format_flags & (JSON_FORMAT_OFF|JSON_FORMAT_PRETTY|JSON_FORMAT_PRETTY_AUTO))
(void) pager_open(arg_pager_flags);
r = table_print_json(t, stdout, arg_json_format_flags);
if (r < 0)
return table_log_print_error(r);
r = 0;
break;
}
case ACTION_MERGE: {
char **p;
/* In merge mode fail if things are already merged. (In --refresh mode below we'll unmerge if
* we find things are already merged...) */
STRV_FOREACH(p, arg_hierarchies) {
_cleanup_free_ char *resolved = NULL;
r = chase_symlinks(*p, arg_root, CHASE_PREFIX_ROOT, &resolved, NULL);
if (r == -ENOENT) {
log_debug_errno(r, "Hierarchy '%s%s' does not exist, ignoring.", strempty(arg_root), *p);
continue;
}
if (r < 0)
return log_error_errno(r, "Failed to resolve path to hierarchy '%s%s': %m", strempty(arg_root), *p);
r = is_our_mount_point(resolved);
if (r < 0)
return r;
if (r > 0)
return log_error_errno(SYNTHETIC_ERRNO(EBUSY),
"Hierarchy '%s' is already merged.", *p);
}
r = merge(images);
break;
}
case ACTION_REFRESH:
r = merge(images); /* Returns > 0 if it did something, i.e. a new overlayfs is mounted
* now. When it does so it implicitly unmounts any overlayfs placed there
* before. Returns == 0 if it did nothing, i.e. no extension images
* found. In this case the old overlayfs remains in place if there was
* one. */
if (r < 0)
return r;
if (r == 0) /* No images found? Then unmerge. The goal of --refresh is after all that after
* having called there's a guarantee that the merge status matches the installed
* extensions. */
r = unmerge();
/* Net result here is that:
*
* 1. If an overlayfs was mounted before and no extensions exist anymore, we'll have unmerged
* things.
*
* 2. If an overlayfs was mounted before, and there are still extensions installed' we'll
* have unmerged and then merged things again.
*
* 3. If an overlayfs so far wasn't mounted, and there are extensions installed, we'll have
* it mounted now.
*
* 4. If there was no overlayfs mount so far, and no extensions installed, we implement a
* NOP.
*/
break;
default:
assert_not_reached("Uneexpected action");
}
return r;
return sysext_main(argc, argv);
}
DEFINE_MAIN_FUNCTION(run);

4
units/systemd-sysext.service
View File

@ -24,8 +24,8 @@ ConditionDirectoryNotEmpty=|/usr/lib/extensions
[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=systemd-sysext --merge
ExecStop=systemd-sysext --unmerge
ExecStart=systemd-sysext merge
ExecStop=systemd-sysext unmerge
[Install]
WantedBy=sysinit.target