Zbigniew Jędrzejewski-Szmek
31ddd87da0
We often have a pattern where the same verb function is used for multiple actions. This leads to an antipattern where we figure out what action needs to be taken from argv[0] multiple times: often once in parse_argv() to figure out what options are allowed, then once again implicitly in dispatch_verb(), and then again in the action verb itself. Let's allow passing a parameter into the verb to simplify this. This matches a pattern we have in conf-parser.h, where we have both void *userdata (more global) and void *data (per-config item). Here, I opted for uintptr_t userdata. It seems that most of the time we'll want to just pass an enum value. This works OK with no casts. I also tried a void* and union. In both cases, much more boilerplate is needed: either a cast or a macro to help avoid compiler warnings. uintptr_t seems generic enough to cover foreseeable usecases with no fuss. This is a noop refactoring. See next commit for an example.
124 lines
4.7 KiB
C
124 lines
4.7 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <stdlib.h>
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#include <unistd.h>
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#include "sd-bus.h"
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#include "alloc-util.h"
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#include "analyze.h"
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#include "analyze-unit-shell.h"
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#include "bus-error.h"
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#include "bus-util.h"
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#include "fd-util.h"
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#include "log.h"
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#include "namespace-util.h"
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#include "pidref.h"
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#include "process-util.h"
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#include "runtime-scope.h"
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#include "strv.h"
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#include "unit-def.h"
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#include "unit-name.h"
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int verb_unit_shell(int argc, char *argv[], uintptr_t _data, void *userdata) {
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_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
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_cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
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_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
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_cleanup_free_ char *unit = NULL;
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int r;
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if (arg_transport != BUS_TRANSPORT_LOCAL)
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Cannot spawn a unit shell for a remote service.");
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r = unit_name_mangle_with_suffix(argv[1], "as unit", UNIT_NAME_MANGLE_WARN, ".service", &unit);
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if (r < 0)
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return log_error_errno(r, "Failed to mangle name '%s': %m", argv[1]);
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r = acquire_bus(&bus, /* use_full_bus= */ NULL);
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if (r < 0)
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return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
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_cleanup_free_ char *object = unit_dbus_path_from_name(unit);
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if (!object)
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return log_oom();
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r = sd_bus_get_property(
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bus,
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"org.freedesktop.systemd1",
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object,
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"org.freedesktop.systemd1.Service",
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"MainPID",
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&error,
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&reply,
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"u");
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if (r < 0)
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return log_error_errno(r, "Failed to get the main PID of %s: %s", unit, bus_error_message(&error, r));
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pid_t pid;
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r = sd_bus_message_read(reply, "u", &pid);
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if (r < 0)
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return log_error_errno(r, "Failed to read the main PID of %s from reply: %m", unit);
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if (pid == 0)
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return log_error_errno(SYNTHETIC_ERRNO(ESRCH), "Unit %s has no MainPID (hint: inactive?)", unit);
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_cleanup_close_ int mntns_fd = -EBADF, root_fd = -EBADF, pidns_fd = -EBADF, netns_fd = -EBADF, userns_fd = -EBADF;
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r = namespace_open(
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pid,
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&pidns_fd,
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&mntns_fd,
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&netns_fd,
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&userns_fd,
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&root_fd);
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if (r < 0)
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return log_error_errno(r, "Failed to retrieve FDs of namespaces of %s: %m", unit);
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_cleanup_strv_free_ char **args = NULL;
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if (argc > 2) {
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args = strv_copy(strv_skip(argv, 2));
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if (!args)
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return log_oom();
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}
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_cleanup_(pidref_done) PidRef child = PIDREF_NULL;
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r = namespace_fork(
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"(unit-shell-ns)",
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"(unit-shell)",
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FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGKILL,
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pidns_fd,
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mntns_fd,
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netns_fd,
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userns_fd,
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root_fd,
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&child);
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if (r < 0)
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return log_error_errno(r, "Failed to fork and enter the namespace of %s: %m", unit);
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if (r == 0) {
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if (args) {
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(void) execvp(args[0], args);
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log_error_errno(errno, "Failed to execute '%s': %m", *args);
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} else {
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(void) execl(DEFAULT_USER_SHELL, "-" DEFAULT_USER_SHELL_NAME, NULL);
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log_debug_errno(errno, "Failed to execute '" DEFAULT_USER_SHELL "', ignoring: %m");
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if (!streq(DEFAULT_USER_SHELL, "/bin/bash")) {
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(void) execl("/bin/bash", "-bash", NULL);
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log_debug_errno(errno, "Failed to execute '/bin/bash', ignoring: %m");
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}
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if (!streq(DEFAULT_USER_SHELL, "/bin/sh")) {
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(void) execl("/bin/sh", "-sh", NULL);
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log_debug_errno(errno, "Failed to execute '/bin/sh', ignoring: %m");
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}
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log_error_errno(errno, "Failed to execute '" DEFAULT_USER_SHELL "', '/bin/bash', and '/bin/sh': %m");
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}
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_exit(EXIT_FAILURE);
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}
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return pidref_wait_for_terminate_and_check(
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"(unit-shell)",
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&child,
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WAIT_LOG_ABNORMAL|WAIT_LOG_NON_ZERO_EXIT_STATUS);
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}
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