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b81b3df1f

Denis Vlasenko
Denis Vlasenko
2007-04-28
FAILED Duration: 10s

Subject

hush: make job control and interactiveness configurable, part 1

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Architecture & Compiler Flags

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

—

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Commit Diff GitHub →

shell/Config.in +9 -0shell/hush.c +102 -14
shell/Config.in+9 -0
@@ -176,6 +176,15 @@ config HUSH
word ), arithmetic expansion, aliases, brace expansion, tilde
expansion, &> and >& redirection of stdout+stderr, etc.
+config HUSH_INTERACTIVE
+ bool "Interactive mode"
+ default y
+ depends on HUSH
+ help
+ Enable interactive mode (Ctrl-Z, Ctrl-C, command editing)
+ in the hush shell. Without this, hush reads and executes
+ stdin just like a shell script from the file.
+
config LASH
bool "lash"
shell/hush.c+102 -14
@@ -51,7 +51,7 @@
* Here Documents ( << word )
* Functions
* Major bugs:
- * job handling woefully incomplete and buggy
+ * job handling woefully incomplete and buggy (improved --vda)
* reserved word execution woefully incomplete and buggy
* to-do:
* port selected bugfixes from post-0.49 busybox lash - done?
@@ -86,6 +86,16 @@
/* Finer-grained debug switch */
//#define DEBUG_SHELL_JOBS
+//TODO: rename HUSH_INTERACTIVE -> HUSH_JOB,
+//create HUSH_INTERACTIVE which controls only prompt + line editing,
+//make HUSH_JOB dependent on it
+
+#if !ENABLE_HUSH_INTERACTIVE
+#undef ENABLE_FEATURE_EDITING
+#define ENABLE_FEATURE_EDITING 0
+#undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
+#define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
+#endif
#define SPECIAL_VAR_SYMBOL 03
#define FLAG_EXIT_FROM_LOOP 1
@@ -169,10 +179,10 @@ struct p_context {
};
struct redir_struct {
+ struct redir_struct *next; /* pointer to the next redirect in the list */
redir_type type; /* type of redirection */
int fd; /* file descriptor being redirected */
int dup; /* -1, or file descriptor being duplicated */
- struct redir_struct *next; /* pointer to the next redirect in the list */
glob_t word; /* *word.gl_pathv is the filename */
};
@@ -190,14 +200,16 @@ struct child_prog {
};
struct pipe {
- int jobid; /* job number */
+ struct pipe *next;
int num_progs; /* total number of programs in job */
int running_progs; /* number of programs running (not exited) */
- char *cmdtext; /* name of job */
char *cmdbuf; /* buffer various argv's point into */
+#if ENABLE_HUSH_INTERACTIVE
+ int jobid; /* job number */
+ char *cmdtext; /* name of job */
pid_t pgrp; /* process group ID for the job */
+#endif
struct child_prog *progs; /* array of commands in pipe */
- struct pipe *next; /* to track background commands */
int stopped_progs; /* number of programs alive, but stopped */
int job_context; /* bitmask defining current context */
pipe_style followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
@@ -205,16 +217,16 @@ struct pipe {
};
struct close_me {
- int fd;
struct close_me *next;
+ int fd;
};
struct variables {
+ struct variables *next;
const char *name;
const char *value;
int flg_export;
int flg_read_only;
- struct variables *next;
};
/* globals, connect us to the outside world
@@ -230,18 +242,22 @@ static unsigned char map[256];
static int fake_mode;
static struct close_me *close_me_head;
static const char *cwd;
-static struct pipe *job_list;
static unsigned last_bg_pid;
+#if ENABLE_HUSH_INTERACTIVE
static int last_jobid;
+static struct pipe *job_list;
/* 'interactive_fd' is a fd# open to ctty, if we have one
* _AND_ if we decided to mess with job control */
static int interactive_fd;
static pid_t saved_task_pgrp;
static pid_t saved_tty_pgrp;
+#else
+enum { interactive_fd = 0 };
+#endif
static const char *PS1;
static const char *PS2;
-static struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
+static struct variables shell_ver = { NULL, "HUSH_VERSION", "0.01", 1, 1 };
static struct variables *top_vars = &shell_ver;
@@ -322,9 +338,11 @@ static int builtin_eval(char **argv);
static int builtin_exec(char **argv);
static int builtin_exit(char **argv);
static int builtin_export(char **argv);
+#if ENABLE_HUSH_INTERACTIVE
static int builtin_fg_bg(char **argv);
-static int builtin_help(char **argv);
static int builtin_jobs(char **argv);
+#endif
+static int builtin_help(char **argv);
static int builtin_pwd(char **argv);
static int builtin_read(char **argv);
static int builtin_set(char **argv);
@@ -387,10 +405,14 @@ static int parse_string_outer(const char *s, int flag);
static int parse_file_outer(FILE *f);
/* job management: */
static int checkjobs(struct pipe* fg_pipe);
+#if ENABLE_HUSH_INTERACTIVE
static int checkjobs_and_fg_shell(struct pipe* fg_pipe);
static void insert_bg_job(struct pipe *pi);
static void remove_bg_job(struct pipe *pi);
static void delete_finished_bg_job(struct pipe *pi);
+#else
+int checkjobs_and_fg_shell(struct pipe* fg_pipe); /* never called */
+#endif
/* local variable support */
static char **make_list_in(char **inp, char *name);
static char *insert_var_value(char *inp);
@@ -405,7 +427,9 @@ static void unset_local_var(const char *name);
* For example, 'unset foo | whatever' will parse and run, but foo will
* still be set at the end. */
static const struct built_in_command bltins[] = {
+#if ENABLE_HUSH_INTERACTIVE
{ "bg", "Resume a job in the background", builtin_fg_bg },
+#endif
{ "break", "Exit for, while or until loop", builtin_not_written },
{ "cd", "Change working directory", builtin_cd },
{ "continue", "Continue for, while or until loop", builtin_not_written },
@@ -415,8 +439,10 @@ static const struct built_in_command bltins[] = {
builtin_exec },
{ "exit", "Exit from shell()", builtin_exit },
{ "export", "Set environment variable", builtin_export },
+#if ENABLE_HUSH_INTERACTIVE
{ "fg", "Bring job into the foreground", builtin_fg_bg },
{ "jobs", "Lists the active jobs", builtin_jobs },
+#endif
{ "pwd", "Print current directory", builtin_pwd },
{ "read", "Input environment variable", builtin_read },
{ "return", "Return from a function", builtin_not_written },
@@ -431,6 +457,9 @@ static const struct built_in_command bltins[] = {
{ NULL, NULL, NULL }
};
+#if ENABLE_HUSH_INTERACTIVE
+
+#if ENABLE_FEATURE_SH_STANDALONE
/* move to libbb? */
static void signal_SA_RESTART(int sig, void (*handler)(int))
{
@@ -440,6 +469,7 @@ static void signal_SA_RESTART(int sig, void (*handler)(int))
sigemptyset(&sa.sa_mask);
sigaction(sig, &sa, NULL);
}
+#endif
/* Signals are grouped, we handle them in batches */
static void set_fatal_sighandler(void (*handler)(int))
@@ -469,6 +499,7 @@ static void set_misc_sighandler(void (*handler)(int))
}
/* SIGCHLD is special and handled separately */
+#if ENABLE_FEATURE_SH_STANDALONE
static void set_every_sighandler(void (*handler)(int))
{
set_fatal_sighandler(handler);
@@ -477,9 +508,9 @@ static void set_every_sighandler(void (*handler)(int))
signal(SIGCHLD, handler);
}
+static struct pipe *nofork_pipe;
struct nofork_save_area nofork_save;
static sigjmp_buf nofork_jb;
-static struct pipe *nofork_pipe;
static void handler_ctrl_c(int sig)
{
@@ -522,6 +553,8 @@ static void handler_ctrl_z(int sig)
siglongjmp(nofork_jb, 1);
}
+#endif
+
/* Restores tty foreground process group, and exits.
* May be called as signal handler for fatal signal
* (will faithfully resend signal to itself, producing correct exit state)
@@ -559,6 +592,16 @@ static void hush_exit(int exitcode)
sigexit(- (exitcode & 0xff));
}
+#else /* !INTERACTIVE */
+
+#define set_fatal_sighandler(handler) ((void)0)
+#define set_jobctrl_sighandler(handler) ((void)0)
+#define set_misc_sighandler(handler) ((void)0)
+#define hush_exit(e) exit(-(e))
+
+#endif /* INTERACTIVE */
+
+
static const char *set_cwd(void)
{
if (cwd == bb_msg_unknown)
@@ -684,6 +727,7 @@ static int builtin_export(char **argv)
return res;
}
+#if ENABLE_HUSH_INTERACTIVE
/* built-in 'fg' and 'bg' handler */
static int builtin_fg_bg(char **argv)
{
@@ -745,6 +789,7 @@ static int builtin_fg_bg(char **argv)
}
return EXIT_SUCCESS;
}
+#endif
/* built-in 'help' handler */
static int builtin_help(char **argv ATTRIBUTE_UNUSED)
@@ -762,6 +807,7 @@ static int builtin_help(char **argv ATTRIBUTE_UNUSED)
return EXIT_SUCCESS;
}
+#if ENABLE_HUSH_INTERACTIVE
/* built-in 'jobs' handler */
static int builtin_jobs(char **argv ATTRIBUTE_UNUSED)
{
@@ -778,6 +824,7 @@ static int builtin_jobs(char **argv ATTRIBUTE_UNUSED)
}
return EXIT_SUCCESS;
}
+#endif
/* built-in 'pwd' handler */
static int builtin_pwd(char **argv ATTRIBUTE_UNUSED)
@@ -1272,7 +1319,9 @@ static void pseudo_exec(struct child_prog *child)
if (child->group) {
debug_printf("runtime nesting to group\n");
// FIXME: do not modify globals! Think vfork!
+#if ENABLE_HUSH_INTERACTIVE
interactive_fd = 0; /* crucial!!!! */
+#endif
rcode = run_list_real(child->group);
/* OK to leak memory by not calling free_pipe_list,
* since this process is about to exit */
@@ -1284,6 +1333,7 @@ static void pseudo_exec(struct child_prog *child)
_exit(EXIT_SUCCESS);
}
+#if ENABLE_HUSH_INTERACTIVE
static const char *get_cmdtext(struct pipe *pi)
{
char **argv;
@@ -1312,7 +1362,9 @@ static const char *get_cmdtext(struct pipe *pi)
p[-1] = '\0';
return pi->cmdtext;
}
+#endif
+#if ENABLE_HUSH_INTERACTIVE
static void insert_bg_job(struct pipe *pi)
{
struct pipe *thejob;
@@ -1376,6 +1428,7 @@ static void delete_finished_bg_job(struct pipe *pi)
free_pipe(pi, 0);
free(pi);
}
+#endif
/* Checks to see if any processes have exited -- if they
have, figure out why and see if a job has completed */
@@ -1383,8 +1436,10 @@ static int checkjobs(struct pipe* fg_pipe)
{
int attributes;
int status;
+#if ENABLE_HUSH_INTERACTIVE
int prognum = 0;
struct pipe *pi;
+#endif
pid_t childpid;
int rcode = 0;
@@ -1401,6 +1456,10 @@ static int checkjobs(struct pipe* fg_pipe)
* 1 <========== bg pipe is not fully done, but exitcode is already known!
*/
+//FIXME: non-interactive bash does not continue even if all processes in fg pipe
+//are stopped. Testcase: "cat | cat" in a script (not on command line)
+// + killall -STOP cat
+
wait_more:
while ((childpid = waitpid(-1, &status, attributes)) > 0) {
const int dead = WIFEXITED(status) || WIFSIGNALED(status);
@@ -1437,8 +1496,10 @@ static int checkjobs(struct pipe* fg_pipe)
fg_pipe->running_progs, fg_pipe->stopped_progs);
if (fg_pipe->running_progs - fg_pipe->stopped_progs <= 0) {
/* All processes in fg pipe have exited/stopped */
+#if ENABLE_HUSH_INTERACTIVE
if (fg_pipe->running_progs)
insert_bg_job(fg_pipe);
+#endif
return rcode;
}
/* There are still running processes in the fg pipe */
@@ -1448,6 +1509,7 @@ static int checkjobs(struct pipe* fg_pipe)
/* fall through to searching process in bg pipes */
}
+#if ENABLE_HUSH_INTERACTIVE
/* We asked to wait for bg or orphaned children */
/* No need to remember exitcode in this case */
for (pi = job_list; pi; pi = pi->next) {
@@ -1458,11 +1520,13 @@ static int checkjobs(struct pipe* fg_pipe)
prognum++;
}
}
+#endif
/* Happens when shell is used as init process (init=/bin/sh) */
debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
goto wait_more;
+#if ENABLE_HUSH_INTERACTIVE
found_pi_and_prognum:
if (dead) {
/* child exited */
@@ -1478,6 +1542,7 @@ static int checkjobs(struct pipe* fg_pipe)
pi->stopped_progs++;
pi->progs[prognum].is_stopped = 1;
}
+#endif
}
/* wait found no children or failed */
@@ -1491,6 +1556,7 @@ static int checkjobs(struct pipe* fg_pipe)
return rcode;
}
+#if ENABLE_HUSH_INTERACTIVE
static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
{
pid_t p;
@@ -1502,11 +1568,14 @@ static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
bb_perror_msg("tcsetpgrp-4a");
return rcode;
}
+#endif
+#if ENABLE_FEATURE_SH_STANDALONE
/* run_pipe_real's helper */
static int run_single_fg_nofork(struct pipe *pi, const struct bb_applet *a,
char **argv)
{
+#if ENABLE_HUSH_INTERACTIVE
int rcode;
/* TSTP handler will store pid etc in pi */
nofork_pipe = pi;
@@ -1532,7 +1601,11 @@ static int run_single_fg_nofork(struct pipe *pi, const struct bb_applet *a,
else
putchar('\n'); /* bash does this on Ctrl-C */
return 0;
+#else
+ return run_nofork_applet(a, argv);
+#endif
}
+#endif
/* run_pipe_real() starts all the jobs, but doesn't wait for anything
* to finish. See checkjobs().
@@ -1564,7 +1637,9 @@ static int run_pipe_real(struct pipe *pi)
const int single_fg = (pi->num_progs == 1 && pi->followup != PIPE_BG);
nextin = 0;
+#if ENABLE_HUSH_INTERACTIVE
pi->pgrp = -1;
+#endif
pi->running_progs = 0;
pi->stopped_progs = 0;
@@ -1691,6 +1766,7 @@ static int run_pipe_real(struct pipe *pi)
if (!child->pid) { /* child */
/* Every child adds itself to new process group
* with pgid == pid of first child in pipe */
+#if ENABLE_HUSH_INTERACTIVE
if (interactive_fd) {
/* Don't do pgrp restore anymore on fatal signals */
set_fatal_sighandler(SIG_DFL);
@@ -1702,6 +1778,7 @@ static int run_pipe_real(struct pipe *pi)
tcsetpgrp(interactive_fd, pi->pgrp);
}
}
+#endif
// in non-interactive case fatal sigs are already SIG_DFL
close_all();
if (nextin != 0) {
@@ -1728,9 +1805,11 @@ static int run_pipe_real(struct pipe *pi)
pi->running_progs++;
+#if ENABLE_HUSH_INTERACTIVE
/* Second and next children need to know pid of first one */
if (pi->pgrp < 0)
pi->pgrp = child->pid;
+#endif
/* Don't check for errors. The child may be dead already,
* in which case setpgid returns error code EACCES. */
@@ -1858,7 +1937,9 @@ static int run_list_real(struct pipe *pi)
/* XXX check bash's behavior with nontrivial pipes */
/* XXX compute jobid */
/* XXX what does bash do with attempts to background builtins? */
+#if ENABLE_HUSH_INTERACTIVE
insert_bg_job(pi);
+#endif
rcode = EXIT_SUCCESS;
} else {
if (interactive_fd) {
@@ -1931,8 +2012,10 @@ static int free_pipe(struct pipe *pi, int indent)
}
free(pi->progs); /* children are an array, they get freed all at once */
pi->progs = NULL;
+#if ENABLE_HUSH_INTERACTIVE
free(pi->cmdtext);
pi->cmdtext = NULL;
+#endif
return ret_code;
}
@@ -3041,6 +3124,7 @@ static int parse_file_outer(FILE *f)
return rcode;
}
+#if ENABLE_HUSH_INTERACTIVE
/* Make sure we have a controlling tty. If we get started under a job
* aware app (like bash for example), make sure we are now in charge so
* we don't fight over who gets the foreground */
@@ -3055,7 +3139,7 @@ static void setup_job_control(void)
/* If we were ran as 'hush &',
* sleep until we are in the foreground. */
while (tcgetpgrp(interactive_fd) != shell_pgrp) {
- /* Send TTIN to ourself (will stop us) */
+ /* Send TTIN to ourself (should stop us) */
kill(- shell_pgrp, SIGTTIN);
shell_pgrp = getpgrp();
}
@@ -3073,6 +3157,7 @@ static void setup_job_control(void)
/* Grab control of the terminal. */
tcsetpgrp(interactive_fd, getpid());
}
+#endif
int hush_main(int argc, char **argv);
int hush_main(int argc, char **argv)
@@ -3095,11 +3180,13 @@ int hush_main(int argc, char **argv)
ifs = NULL;
/* map[] is taken care of with call to update_ifs_map() */
fake_mode = 0;
- interactive_fd = 0;
close_me_head = NULL;
+#if ENABLE_HUSH_INTERACTIVE
+ interactive_fd = 0;
last_bg_pid = 0;
job_list = NULL;
last_jobid = 0;
+#endif
/* Initialize some more globals to non-zero values */
set_cwd();
@@ -3154,6 +3241,7 @@ int hush_main(int argc, char **argv)
#endif
}
}
+#if ENABLE_HUSH_INTERACTIVE
/* A shell is interactive if the '-i' flag was given, or if all of
* the following conditions are met:
* no -c command
@@ -3180,7 +3268,6 @@ int hush_main(int argc, char **argv)
// to (inadvertently) close/redirect it
}
}
-
debug_printf("\ninteractive_fd=%d\n", interactive_fd);
if (interactive_fd) {
/* Looks like they want an interactive shell */
@@ -3196,6 +3283,7 @@ int hush_main(int argc, char **argv)
printf("Enter 'help' for a list of built-in commands.\n\n");
#endif
}
+#endif
if (argv[optind] == NULL) {
opt = parse_file_outer(stdin);