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Systemd/src/systemctl/systemctl-edit.c
williamvds 85c5d313b5
systemctl: show original contents when editing unit 
A comment indicates the start of the new contents of the override file,
and another indicates that lines following it will be discarded once
editing is finished.
The contents of the unit file and drop-ins are listed out after this
last marker.

Adds WRITE_STRING_FILE_TRUNCATE to set O_TRUNC when opening a file.

Thanks to cgzones for providing the required SELinux function calls.

Co-authored-by: Christian Göttsche <cgzones@googlemail.com>
2020-10-21 21:20:01 +01:00

593 lines
22 KiB
C
Raw Blame History

/* SPDX-License-Identifier: LGPL-2.1+ */
#include "bus-error.h"
#include "copy.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "mkdir.h"
#include "pager.h"
#include "path-util.h"
#include "pretty-print.h"
#include "process-util.h"
#include "selinux-util.h"
#include "stat-util.h"
#include "systemctl-daemon-reload.h"
#include "systemctl-edit.h"
#include "systemctl-util.h"
#include "systemctl.h"
#include "terminal-util.h"
#include "tmpfile-util.h"
#define EDIT_MARKER_START "### Anything between here and the comment below will become the new contents of the file"
#define EDIT_MARKER_END "### Lines below this comment will be discarded"
int cat(int argc, char *argv[], void *userdata) {
_cleanup_(hashmap_freep) Hashmap *cached_name_map = NULL, *cached_id_map = NULL;
_cleanup_(lookup_paths_free) LookupPaths lp = {};
_cleanup_strv_free_ char **names = NULL;
char **name;
sd_bus *bus;
bool first = true;
int r, rc = 0;
/* Include all units by default — i.e. continue as if the --all option was used */
if (strv_isempty(arg_states))
arg_all = true;
if (arg_transport != BUS_TRANSPORT_LOCAL)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Cannot remotely cat units.");
r = lookup_paths_init(&lp, arg_scope, 0, arg_root);
if (r < 0)
return log_error_errno(r, "Failed to determine unit paths: %m");
r = acquire_bus(BUS_MANAGER, &bus);
if (r < 0)
return r;
r = expand_unit_names(bus, strv_skip(argv, 1), NULL, &names, NULL);
if (r < 0)
return log_error_errno(r, "Failed to expand names: %m");
r = maybe_extend_with_unit_dependencies(bus, &names);
if (r < 0)
return r;
(void) pager_open(arg_pager_flags);
STRV_FOREACH(name, names) {
_cleanup_free_ char *fragment_path = NULL;
_cleanup_strv_free_ char **dropin_paths = NULL;
r = unit_find_paths(bus, *name, &lp, false, &cached_name_map, &cached_id_map, &fragment_path, &dropin_paths);
if (r == -ERFKILL) {
printf("%s# Unit %s is masked%s.\n",
ansi_highlight_magenta(),
*name,
ansi_normal());
continue;
}
if (r == -EKEYREJECTED) {
printf("%s# Unit %s could not be loaded.%s\n",
ansi_highlight_magenta(),
*name,
ansi_normal());
continue;
}
if (r < 0)
return r;
if (r == 0) {
/* Skip units which have no on-disk counterpart, but propagate the error to the
* user */
rc = -ENOENT;
continue;
}
if (first)
first = false;
else
puts("");
if (need_daemon_reload(bus, *name) > 0) /* ignore errors (<0), this is informational output */
fprintf(stderr,
"%s# Warning: %s changed on disk, the version systemd has loaded is outdated.\n"
"%s# This output shows the current version of the unit's original fragment and drop-in files.\n"
"%s# If fragments or drop-ins were added or removed, they are not properly reflected in this output.\n"
"%s# Run 'systemctl%s daemon-reload' to reload units.%s\n",
ansi_highlight_red(),
*name,
ansi_highlight_red(),
ansi_highlight_red(),
ansi_highlight_red(),
arg_scope == UNIT_FILE_SYSTEM ? "" : " --user",
ansi_normal());
r = cat_files(fragment_path, dropin_paths, 0);
if (r < 0)
return r;
}
return rc;
}
static int create_edit_temp_file(const char *new_path, const char *original_path, char ** const original_unit_paths, char **ret_tmp_fn) {
_cleanup_free_ char *t = NULL;
int r;
assert(new_path);
assert(ret_tmp_fn);
r = tempfn_random(new_path, NULL, &t);
if (r < 0)
return log_error_errno(r, "Failed to determine temporary filename for \"%s\": %m", new_path);
r = mkdir_parents_label(new_path, 0755);
if (r < 0)
return log_error_errno(r, "Failed to create directories for \"%s\": %m", new_path);
if (original_path) {
r = mac_selinux_create_file_prepare(new_path, S_IFREG);
if (r < 0)
return r;
r = copy_file(original_path, t, 0, 0644, 0, 0, COPY_REFLINK);
if (r == -ENOENT) {
r = touch(t);
mac_selinux_create_file_clear();
if (r < 0)
return log_error_errno(r, "Failed to create temporary file \"%s\": %m", t);
} else {
mac_selinux_create_file_clear();
if (r < 0)
return log_error_errno(r, "Failed to create temporary file for \"%s\": %m", new_path);
}
} else if (original_unit_paths) {
_cleanup_free_ char *new_contents = NULL;
_cleanup_fclose_ FILE *f = NULL;
char **path;
size_t size;
r = mac_selinux_create_file_prepare(new_path, S_IFREG);
if (r < 0)
return r;
f = fopen(t, "we");
mac_selinux_create_file_clear();
if (!f)
return log_error_errno(errno, "Failed to open \"%s\": %m", t);
r = fchmod(fileno(f), 0644);
if (r < 0)
return log_error_errno(errno, "Failed to change mode of \"%s\": %m", t);
r = read_full_file(new_path, &new_contents, &size);
if (r < 0 && r != -ENOENT)
return log_error_errno(r, "Failed to read \"%s\": %m", new_path);
fprintf(f,
"### Editing %s\n"
EDIT_MARKER_START
"\n\n%s%s\n"
EDIT_MARKER_END,
new_path,
strempty(new_contents),
new_contents && endswith(new_contents, "\n") ? "" : "\n");
/* Add a comment with the contents of the original unit files */
STRV_FOREACH(path, original_unit_paths) {
_cleanup_free_ char *contents = NULL;
/* Skip the file that's being edited */
if (path_equal(*path, new_path))
continue;
r = read_full_file(*path, &contents, &size);
if (r < 0)
return log_error_errno(r, "Failed to read \"%s\": %m", *path);
fprintf(f, "\n\n### %s", *path);
if (!isempty(contents)) {
contents = strreplace(strstrip(contents), "\n", "\n# ");
if (!contents)
return log_oom();
fprintf(f, "\n# %s", contents);
}
}
r = fflush_and_check(f);
if (r < 0)
return log_error_errno(r, "Failed to create temporary file \"%s\": %m", t);
}
*ret_tmp_fn = TAKE_PTR(t);
return 0;
}
static int get_file_to_edit(
const LookupPaths *paths,
const char *name,
char **ret_path) {
_cleanup_free_ char *path = NULL, *run = NULL;
assert(name);
assert(ret_path);
path = path_join(paths->persistent_config, name);
if (!path)
return log_oom();
if (arg_runtime) {
run = path_join(paths->runtime_config, name);
if (!run)
return log_oom();
}
if (arg_runtime) {
if (access(path, F_OK) >= 0)
return log_error_errno(SYNTHETIC_ERRNO(EEXIST),
"Refusing to create \"%s\" because it would be overridden by \"%s\" anyway.",
run, path);
*ret_path = TAKE_PTR(run);
} else
*ret_path = TAKE_PTR(path);
return 0;
}
static int unit_file_create_new(
const LookupPaths *paths,
const char *unit_name,
const char *suffix,
char ** const original_unit_paths,
char **ret_new_path,
char **ret_tmp_path) {
_cleanup_free_ char *new_path = NULL, *tmp_path = NULL;
const char *ending;
int r;
assert(unit_name);
assert(ret_new_path);
assert(ret_tmp_path);
ending = strjoina(unit_name, suffix);
r = get_file_to_edit(paths, ending, &new_path);
if (r < 0)
return r;
r = create_edit_temp_file(new_path, NULL, original_unit_paths, &tmp_path);
if (r < 0)
return r;
*ret_new_path = TAKE_PTR(new_path);
*ret_tmp_path = TAKE_PTR(tmp_path);
return 0;
}
static int unit_file_create_copy(
const LookupPaths *paths,
const char *unit_name,
const char *fragment_path,
char **ret_new_path,
char **ret_tmp_path) {
_cleanup_free_ char *new_path = NULL, *tmp_path = NULL;
int r;
assert(fragment_path);
assert(unit_name);
assert(ret_new_path);
assert(ret_tmp_path);
r = get_file_to_edit(paths, unit_name, &new_path);
if (r < 0)
return r;
if (!path_equal(fragment_path, new_path) && access(new_path, F_OK) >= 0) {
char response;
r = ask_char(&response, "yn", "\"%s\" already exists. Overwrite with \"%s\"? [(y)es, (n)o] ", new_path, fragment_path);
if (r < 0)
return r;
if (response != 'y')
return log_warning_errno(SYNTHETIC_ERRNO(EKEYREJECTED), "%s skipped.", unit_name);
}
r = create_edit_temp_file(new_path, fragment_path, NULL, &tmp_path);
if (r < 0)
return r;
*ret_new_path = TAKE_PTR(new_path);
*ret_tmp_path = TAKE_PTR(tmp_path);
return 0;
}
static int run_editor(char **paths) {
int r;
assert(paths);
r = safe_fork("(editor)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_RLIMIT_NOFILE_SAFE|FORK_LOG|FORK_WAIT, NULL);
if (r < 0)
return r;
if (r == 0) {
char **editor_args = NULL, **tmp_path, **original_path;
size_t n_editor_args = 0, i = 1, argc;
const char **args, *editor, *p;
argc = strv_length(paths)/2 + 1;
/* SYSTEMD_EDITOR takes precedence over EDITOR which takes precedence over VISUAL. If
* neither SYSTEMD_EDITOR nor EDITOR nor VISUAL are present, we try to execute well known
* editors. */
editor = getenv("SYSTEMD_EDITOR");
if (!editor)
editor = getenv("EDITOR");
if (!editor)
editor = getenv("VISUAL");
if (!isempty(editor)) {
editor_args = strv_split(editor, WHITESPACE);
if (!editor_args) {
(void) log_oom();
_exit(EXIT_FAILURE);
}
n_editor_args = strv_length(editor_args);
argc += n_editor_args - 1;
}
args = newa(const char*, argc + 1);
if (n_editor_args > 0) {
args[0] = editor_args[0];
for (; i < n_editor_args; i++)
args[i] = editor_args[i];
}
STRV_FOREACH_PAIR(original_path, tmp_path, paths)
args[i++] = *tmp_path;
args[i] = NULL;
if (n_editor_args > 0)
execvp(args[0], (char* const*) args);
FOREACH_STRING(p, "editor", "nano", "vim", "vi") {
args[0] = p;
execvp(p, (char* const*) args);
/* We do not fail if the editor doesn't exist because we want to try each one of them
* before failing. */
if (errno != ENOENT) {
log_error_errno(errno, "Failed to execute %s: %m", editor);
_exit(EXIT_FAILURE);
}
}
log_error("Cannot edit unit(s), no editor available. Please set either $SYSTEMD_EDITOR, $EDITOR or $VISUAL.");
_exit(EXIT_FAILURE);
}
return 0;
}
static int find_paths_to_edit(sd_bus *bus, char **names, char ***paths) {
_cleanup_(hashmap_freep) Hashmap *cached_name_map = NULL, *cached_id_map = NULL;
_cleanup_(lookup_paths_free) LookupPaths lp = {};
char **name;
int r;
assert(names);
assert(paths);
r = lookup_paths_init(&lp, arg_scope, 0, arg_root);
if (r < 0)
return r;
STRV_FOREACH(name, names) {
_cleanup_free_ char *path = NULL, *new_path = NULL, *tmp_path = NULL, *tmp_name = NULL;
_cleanup_strv_free_ char **unit_paths = NULL;
const char *unit_name;
r = unit_find_paths(bus, *name, &lp, false, &cached_name_map, &cached_id_map, &path, &unit_paths);
if (r == -EKEYREJECTED) {
/* If loading of the unit failed server side complete, then the server won't tell us
* the unit file path. In that case, find the file client side. */
log_debug_errno(r, "Unit '%s' was not loaded correctly, retrying client-side.", *name);
r = unit_find_paths(bus, *name, &lp, true, &cached_name_map, &cached_id_map, &path, NULL);
}
if (r == -ERFKILL)
return log_error_errno(r, "Unit '%s' masked, cannot edit.", *name);
if (r < 0)
return r;
if (r == 0) {
assert(!path);
if (!arg_force) {
log_info("Run 'systemctl edit%s --force --full %s' to create a new unit.",
arg_scope == UNIT_FILE_GLOBAL ? " --global" :
arg_scope == UNIT_FILE_USER ? " --user" : "",
*name);
return -ENOENT;
}
/* Create a new unit from scratch */
unit_name = *name;
r = unit_file_create_new(&lp, unit_name,
arg_full ? NULL : ".d/override.conf",
NULL, &new_path, &tmp_path);
} else {
assert(path);
unit_name = basename(path);
/* We follow unit aliases, but we need to propagate the instance */
if (unit_name_is_valid(*name, UNIT_NAME_INSTANCE) &&
unit_name_is_valid(unit_name, UNIT_NAME_TEMPLATE)) {
_cleanup_free_ char *instance = NULL;
r = unit_name_to_instance(*name, &instance);
if (r < 0)
return r;
r = unit_name_replace_instance(unit_name, instance, &tmp_name);
if (r < 0)
return r;
unit_name = tmp_name;
}
if (arg_full)
r = unit_file_create_copy(&lp, unit_name, path, &new_path, &tmp_path);
else {
r = strv_prepend(&unit_paths, path);
if (r < 0)
return log_oom();
r = unit_file_create_new(&lp, unit_name, ".d/override.conf", unit_paths, &new_path, &tmp_path);
}
}
if (r < 0)
return r;
r = strv_push_pair(paths, new_path, tmp_path);
if (r < 0)
return log_oom();
new_path = tmp_path = NULL;
}
return 0;
}
static int trim_edit_markers(const char *path) {
_cleanup_free_ char *contents = NULL;
char *contents_start = NULL;
const char *contents_end = NULL;
size_t size;
int r;
/* Trim out the lines between the two markers */
r = read_full_file(path, &contents, &size);
if (r < 0)
return log_error_errno(r, "Failed to read temporary file \"%s\": %m", path);
contents_start = strstr(contents, EDIT_MARKER_START);
if (contents_start)
contents_start += strlen(EDIT_MARKER_START);
else
contents_start = contents;
contents_end = strstr(contents_start, EDIT_MARKER_END);
if (contents_end)
strshorten(contents_start, contents_end - contents_start);
contents_start = strstrip(contents_start);
/* Write new contents if the trimming actually changed anything */
if (strlen(contents) != size) {
r = write_string_file(path, contents_start, WRITE_STRING_FILE_CREATE | WRITE_STRING_FILE_TRUNCATE | WRITE_STRING_FILE_AVOID_NEWLINE);
if (r < 0)
return log_error_errno(r, "Failed to modify temporary file \"%s\": %m", path);
}
return 0;
}
int edit(int argc, char *argv[], void *userdata) {
_cleanup_(lookup_paths_free) LookupPaths lp = {};
_cleanup_strv_free_ char **names = NULL;
_cleanup_strv_free_ char **paths = NULL;
char **original, **tmp;
sd_bus *bus;
int r;
if (!on_tty())
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Cannot edit units if not on a tty.");
if (arg_transport != BUS_TRANSPORT_LOCAL)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Cannot edit units remotely.");
r = lookup_paths_init(&lp, arg_scope, 0, arg_root);
if (r < 0)
return log_error_errno(r, "Failed to determine unit paths: %m");
r = mac_selinux_init();
if (r < 0)
return r;
r = acquire_bus(BUS_MANAGER, &bus);
if (r < 0)
return r;
r = expand_unit_names(bus, strv_skip(argv, 1), NULL, &names, NULL);
if (r < 0)
return log_error_errno(r, "Failed to expand names: %m");
STRV_FOREACH(tmp, names) {
r = unit_is_masked(bus, &lp, *tmp);
if (r < 0)
return r;
if (r > 0)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Cannot edit %s: unit is masked.", *tmp);
}
r = find_paths_to_edit(bus, names, &paths);
if (r < 0)
return r;
if (strv_isempty(paths))
return -ENOENT;
r = run_editor(paths);
if (r < 0)
goto end;
STRV_FOREACH_PAIR(original, tmp, paths) {
/* If the temporary file is empty we ignore it. This allows the user to cancel the
* modification. */
r = trim_edit_markers(*tmp);
if (r < 0)
continue;
if (null_or_empty_path(*tmp)) {
log_warning("Editing \"%s\" canceled: temporary file is empty.", *original);
continue;
}
r = rename(*tmp, *original);
if (r < 0) {
r = log_error_errno(errno, "Failed to rename \"%s\" to \"%s\": %m", *tmp, *original);
goto end;
}
}
r = 0;
if (!arg_no_reload && !install_client_side())
r = daemon_reload(argc, argv, userdata);
end:
STRV_FOREACH_PAIR(original, tmp, paths) {
(void) unlink(*tmp);
/* Removing empty dropin dirs */
if (!arg_full) {
_cleanup_free_ char *dir;
dir = dirname_malloc(*original);
if (!dir)
return log_oom();
/* No need to check if the dir is empty, rmdir does nothing if it is not the case. */
(void) rmdir(dir);
}
}
return r;
}
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