From 43b8a1cc3825eedb85e10cbe2f91a20fbe7c4434 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Wed, 30 Apr 2014 17:38:27 +0200 Subject: crond: implement "SHELL=prog" in crontab. Export LOGNAME as POSIX wants function old new delta fork_job 343 456 +113 load_crontab 688 777 +89 crond_main 1456 1434 -22 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 2/1 up/down: 202/-22) Total: 180 bytes Signed-off-by: Denys Vlasenko --- miscutils/crond.c | 72 ++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 48 insertions(+), 24 deletions(-) (limited to 'miscutils') diff --git a/miscutils/crond.c b/miscutils/crond.c index 210da5f47..3659b9a6f 100644 --- a/miscutils/crond.c +++ b/miscutils/crond.c @@ -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"); -- cgit v1.2.3