← Commit list

43b8a1cc3

Denys Vlasenko

2014-04-30

SUCCESS Duration: 138s

Subject

crond: implement "SHELL=prog" in crontab. Export LOGNAME as POSIX wants

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

miscutils/crond.c +48 -24

miscutils/crond.c+48 -24

@@ -104,6 +104,7 @@ typedef struct CronLine {
	int cl_empty_mail_size; /* size of mail header only, 0 if no mailfile */
	char cl_mailto; / whom to mail results, may be NULL */
	#endif
+	char *cl_shell;
	/* ordered by size, not in natural order. makes code smaller: */
	char cl_Dow[7]; /* 0-6, beginning sunday */
	char cl_Mons[12]; /* 0-11 */
@@ -135,6 +136,8 @@ struct globals {
	#if SETENV_LEAKS
	char *env_var_user;
	char *env_var_home;
+	char *env_var_shell;
+	char *env_var_logname;
	#endif
	} FIX_ALIASING;
	#define G ((struct globals)&bb_common_bufsiz1)
@@ -397,6 +400,7 @@ static void load_crontab(const char *fileName)
	#if ENABLE_FEATURE_CROND_CALL_SENDMAIL
	char *mailTo = NULL;
	#endif
+	char *shell = NULL;

	delete_cronfile(fileName);

@@ -441,7 +445,12 @@ static void load_crontab(const char *fileName)
	#endif /* otherwise just ignore such lines */
	continue;
	}
-	//TODO: handle SHELL=, HOME= too? "man crontab" says:
+	if (0 == strncmp(tokens[0], "SHELL=", 6)) {
+	free(shell);
+	shell = xstrdup(&tokens[0][6]);
+	continue;
+	}
+	//TODO: handle HOME= too? "man crontab" says:
	//name = value
	//
	//where the spaces around the equal-sign (=) are optional, and any subsequent
@@ -453,6 +462,7 @@ static void load_crontab(const char *fileName)
	//SHELL is set to /bin/sh, and LOGNAME and HOME are set from the /etc/passwd
	//line of the crontab's owner. HOME and SHELL may be overridden by settings
	//in the crontab; LOGNAME may not.
+
	/* check if a minimum of tokens is specified */
	if (n < 6)
	continue;
@@ -472,9 +482,9 @@ static void load_crontab(const char *fileName)
	/* copy mailto (can be NULL) */
	line->cl_mailto = xstrdup(mailTo);
	#endif
+	line->cl_shell = xstrdup(shell);
	/* copy command */
	line->cl_cmd = xstrdup(tokens[5]);
-	log5(" command:%s", tokens[5]);
	pline = &line->cl_next;
	//bb_error_msg("M[%s]F[%s][%s][%s][%s][%s][%s]", mailTo, tokens[0], tokens[1], tokens[2], tokens[3], tokens[4], tokens[5]);
	}
@@ -484,6 +494,10 @@ static void load_crontab(const char *fileName)
	G.cron_files = file;
	}
	config_close(parser);
+	#if ENABLE_FEATURE_CROND_CALL_SENDMAIL
+	free(mailTo);
+	#endif
+	free(shell);
	}

	static void process_cron_update_file(void)
@@ -555,19 +569,22 @@ static void safe_setenv(char *pvar_val, const char var, const char *val)
	}
	#endif

-	static void set_env_vars(struct passwd *pas)
+	static void set_env_vars(struct passwd pas, const char shell)
	{
+	/* POSIX requires crond to set up at least HOME, LOGNAME, PATH, SHELL.
+	* We assume crond inherited suitable PATH.
+	*/
	#if SETENV_LEAKS
+	safe_setenv(&G.env_var_logname, "LOGNAME", pas->pw_name);
	safe_setenv(&G.env_var_user, "USER", pas->pw_name);
	safe_setenv(&G.env_var_home, "HOME", pas->pw_dir);
-	/* if we want to set user's shell instead: */
-	/safe_setenv(G.env_var_shell, "SHELL", pas->pw_shell);/
+	safe_setenv(&G.env_var_shell, "SHELL", shell);
	#else
+	xsetenv("LOGNAME", pas->pw_name);
	xsetenv("USER", pas->pw_name);
	xsetenv("HOME", pas->pw_dir);
+	xsetenv("SHELL", shell);
	#endif
-	/* currently, we use constant one: */
-	/setenv("SHELL", DEFAULT_SHELL, 1); - done earlier /
	}

	static void change_user(struct passwd *pas)
@@ -584,12 +601,11 @@ static void change_user(struct passwd *pas)
	#if ENABLE_FEATURE_CROND_CALL_SENDMAIL

	static pid_t
-	fork_job(const char *user, int mailFd,
-	const char *prog,
-	const char shell_cmd / if NULL, we run sendmail */
-	) {
-	smallint sv_logmode;
+	fork_job(const char user, int mailFd, CronLine line, bool run_sendmail)
+	{
	struct passwd *pas;
+	const char shell, prog;
+	smallint sv_logmode;
	pid_t pid;

	/* prepare things before vfork */
@@ -598,7 +614,11 @@ fork_job(const char *user, int mailFd,
	bb_error_msg("can't get uid for %s", user);
	goto err;
	}
-	set_env_vars(pas);
+
+	shell = line->cl_shell ? line->cl_shell : DEFAULT_SHELL;
+	prog = run_sendmail ? SENDMAIL : shell;
+
+	set_env_vars(pas, shell);

	sv_logmode = logmode;
	pid = vfork();
@@ -608,12 +628,15 @@ fork_job(const char *user, int mailFd,
	change_user(pas);
	log5("child running %s", prog);
	if (mailFd >= 0) {
-	xmove_fd(mailFd, shell_cmd ? 1 : 0);
+	xmove_fd(mailFd, run_sendmail ? 0 : 1);
	dup2(1, 2);
	}
	/* crond 3.0pl1-100 puts tasks in separate process groups */
	bb_setpgrp();
-	execlp(prog, prog, (shell_cmd ? "-c" : SENDMAIL_ARGS), shell_cmd, (char *) NULL);
+	if (!run_sendmail)
+	execlp(prog, prog, "-c", line->cl_cmd, (char *) NULL);
+	else
+	execlp(prog, prog, SENDMAIL_ARGS, (char *) NULL);
	/*
	* I want this error message on stderr too,
	* even if other messages go only to syslog:
@@ -662,7 +685,7 @@ static void start_one_job(const char user, CronLine line)
	}
	}

-	line->cl_pid = fork_job(user, mailFd, DEFAULT_SHELL, line->cl_cmd);
+	line->cl_pid = fork_job(user, mailFd, line, /sendmail?/ 0);
	if (mailFd >= 0) {
	if (line->cl_pid <= 0) {
	unlink(mailFile);
@@ -718,13 +741,14 @@ static void process_finished_job(const char user, CronLine line)
	}
	line->cl_empty_mail_size = 0;
	/* if (line->cl_mailto) - always true if cl_empty_mail_size was nonzero */
-	line->cl_pid = fork_job(user, mailFd, SENDMAIL, NULL);
+	line->cl_pid = fork_job(user, mailFd, line, /sendmail?/ 1);
	}

	#else /* !ENABLE_FEATURE_CROND_CALL_SENDMAIL */

	static void start_one_job(const char user, CronLine line)
	{
+	const char *shell;
	struct passwd *pas;
	pid_t pid;

@@ -735,7 +759,8 @@ static void start_one_job(const char user, CronLine line)
	}

	/* Prepare things before vfork */
-	set_env_vars(pas);
+	shell = line->cl_shell ? line->cl_shell : DEFAULT_SHELL;
+	set_env_vars(pas, shell);

	/* Fork as the user in question and run program */
	pid = vfork();
@@ -743,11 +768,11 @@ static void start_one_job(const char user, CronLine line)
	/* CHILD */
	/* initgroups, setgid, setuid, and chdir to home or CRON_DIR */
	change_user(pas);
-	log5("child running %s", DEFAULT_SHELL);
+	log5("child running %s", shell);
	/* crond 3.0pl1-100 puts tasks in separate process groups */
	bb_setpgrp();
-	execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", line->cl_cmd, (char *) NULL);
-	bb_error_msg_and_die("can't execute '%s' for user %s", DEFAULT_SHELL, user);
+	execl(shell, shell, "-c", line->cl_cmd, (char *) NULL);
+	bb_error_msg_and_die("can't execute '%s' for user %s", shell, user);
	}
	if (pid < 0) {
	bb_perror_msg("vfork");
@@ -916,11 +941,10 @@ int crond_main(int argc UNUSED_PARAM, char **argv)
	logmode = LOGMODE_SYSLOG;
	}

-	reopen_logfile_to_stderr();
+	//signal(SIGHUP, SIG_IGN); /* ? original crond dies on HUP... */

+	reopen_logfile_to_stderr();
	xchdir(G.crontab_dir_name);
-	//signal(SIGHUP, SIG_IGN); /* ? original crond dies on HUP... */
-	xsetenv("SHELL", DEFAULT_SHELL); /* once, for all future children */
	log8("crond (busybox "BB_VER") started, log level %d", G.log_level);
	rescan_crontab_dir();
	write_pidfile(CONFIG_PID_FILE_PATH "/crond.pid");