configured_command.c

// SPDX-License-Identifier: Apache-2.0

#include "config.h"

#include "configured_command.h"

#include <stdbool.h>
#include <signal.h>  // for SIGPIPE
#include <stdio.h>   // for snprintf
#include <stdlib.h>  // for EXIT_FAILURE, EXIT_SUCCESS
#include <unistd.h>  // for _exit, execl, fork, pid_t, setsid

#include "env_settings.h"
#include "logging.h"
#include "process_util.h"
#include "xsl_signal.h"

static void ExecShellOrExit(const char *label, const char *command) {
  execl("/bin/sh", "sh", "-c", command, (char *)NULL);
  LogErrno("execl /bin/sh -c for %s", label);
  _exit(EXIT_FAILURE);
}

bool FormatKeyCommandEnvName(char *dst, size_t dst_size, const char *keyname) {
  int len = snprintf(dst, dst_size, "XSECURELOCK_KEY_%s_COMMAND", keyname);
  if (len <= 0 || (size_t)len >= dst_size) {
    Log("Wow, pretty long keysym names you got there");
    return false;
  }
  return true;
}

bool RunShellCommandValue(const char *label, const char *command,
                          bool background) {
  if (command == NULL || *command == '\0') {
    return true;
  }

  pid_t childpid = ForkWithoutSigHandlers();
  if (childpid == -1) {
    LogErrno("fork for %s", label);
    return false;
  }

  if (childpid == 0) {
    ResetSignalToDefaultOrExit(SIGPIPE, label);
    if (background) {
      if (setsid() == (pid_t)-1) {
        LogErrno("setsid for %s", label);
        _exit(EXIT_FAILURE);
      }

      pid_t grandchildpid = fork();
      if (grandchildpid == -1) {
        LogErrno("fork for %s", label);
        _exit(EXIT_FAILURE);
      }
      if (grandchildpid != 0) {
        _exit(EXIT_SUCCESS);
      }
    }

    ExecShellOrExit(label, command);
  }

  int status = 0;
  if (!WaitPidNoEintr(childpid, &status)) {
    LogErrno("waitpid for %s", label);
    return false;
  }
  return LogWaitStatus(label, status);
}

bool RunShellCommandFromEnv(const char *env_name, bool background) {
  const char *command = GetStringSetting(env_name, "");
  return RunShellCommandValue(env_name, command, background);
}