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

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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 <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2014-04-30 17:38:27 +02:00
parent d5929d602e
commit 43b8a1cc38
1 changed files with 49 additions and 25 deletions
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74
miscutils/crond.c
View File

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