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54e7ffb3a

Denis Vlasenko
Denis Vlasenko
2007-04-21
FAILED Duration: 11s

Subject

hush: begin fixing non-functional job control

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 →

libbb/error_msg_and_die.c +4 -2shell/README +6 -0shell/hush.c +198 -72
libbb/error_msg_and_die.c+4 -2
@@ -10,14 +10,16 @@
#include "libbb.h"
int die_sleep;
-#if ENABLE_FEATURE_PREFER_APPLETS
+#if ENABLE_FEATURE_PREFER_APPLETS || ENABLE_HUSH
jmp_buf die_jmp;
#endif
void xfunc_die(void)
{
if (die_sleep) {
- if (ENABLE_FEATURE_PREFER_APPLETS && die_sleep < 0) {
+ if ((ENABLE_FEATURE_PREFER_APPLETS || ENABLE_HUSH)
+ && die_sleep < 0
+ ) {
/* Special case. We arrive here if NOFORK applet
* calls xfunc, which then decides to die.
* We don't die, but jump instead back to caller.
shell/README+6 -0
@@ -1,5 +1,11 @@
Various bits of what is known about busybox shells, in no particular order.
+2007-04-21
+hush: removed setsid() and made job control sort-of-sometimes-work.
+Ctrl-C in "rm -i" works now except for SH_STANDALONE case.
+"sleep 1 | exit 3" + "echo $?" works, "sleep 1 | exit 3; echo $?"
+shows exitcode 0 (should be 3). "sleep 1 | sleep 2 &" fails horribly.
+
2007-04-14
lash, hush: both do setsid() and as a result don't have ctty!
Ctrl-C doesn't work for any child (try rm -i), etc...
shell/hush.c+198 -72
@@ -81,9 +81,6 @@
#include <glob.h> /* glob, of course */
#include <getopt.h> /* should be pretty obvious */
-//#include <sys/wait.h>
-//#include <signal.h>
-
/* #include <dmalloc.h> */
/* #define DEBUG_SHELL */
@@ -91,7 +88,7 @@
#define SPECIAL_VAR_SYMBOL 03
#define FLAG_EXIT_FROM_LOOP 1
#define FLAG_PARSE_SEMICOLON (1 << 1) /* symbol ';' is special for parser */
-#define FLAG_REPARSING (1 << 2) /* >=2nd pass */
+#define FLAG_REPARSING (1 << 2) /* >=2nd pass */
typedef enum {
REDIRECT_INPUT = 1,
@@ -193,7 +190,7 @@ struct child_prog {
struct pipe {
int jobid; /* job number */
int num_progs; /* total number of programs in job */
- int running_progs; /* number of programs running */
+ int running_progs; /* number of programs running (not exited) */
char *text; /* name of job */
char *cmdbuf; /* buffer various argv's point into */
pid_t pgrp; /* process group ID for the job */
@@ -229,13 +226,17 @@ extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
static const char *ifs;
static unsigned char map[256];
static int fake_mode;
-static int interactive;
static struct close_me *close_me_head;
static const char *cwd;
static struct pipe *job_list;
static unsigned last_bg_pid;
static int last_jobid;
-static unsigned shell_terminal;
+/* '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;
+
static const char *PS1;
static const char *PS2;
static struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
@@ -308,7 +309,7 @@ static void __syntax(const char *file, int line)
{
bb_error_msg("syntax error %s:%d", file, line);
}
-// NB: was __FILE__, but that produces full path sometimes, so...
+/* NB: was __FILE__, but that produces full path sometimes, so... */
#define syntax() __syntax("hush.c", __LINE__)
/* Index of subroutines: */
@@ -425,6 +426,84 @@ static const struct built_in_command bltins[] = {
{ NULL, NULL, NULL }
};
+/* 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)
+ * or called directly with -EXITCODE.
+ * We also call it if xfunc is exiting. */
+static void sigexit(int sig) ATTRIBUTE_NORETURN;
+static void sigexit(int sig)
+{
+ sigset_t block_all;
+
+ /* Disable all signals: job control, SIGPIPE, etc. */
+ sigfillset(&block_all);
+ sigprocmask(SIG_SETMASK, &block_all, NULL);
+
+ if (interactive_fd) {
+ if (sig > 0) {
+ enum { KILLED = sizeof("Killed by signal ")-1 };
+ char buf[KILLED + sizeof(int)*3 + 1];
+ char *p;
+
+ /* bash actually says "Illegal instruction" and the like */
+ strcpy(buf, "Killed by signal ");
+ p = utoa_to_buf(sig, buf+KILLED, sizeof(buf)-KILLED);
+ *p++ = '\n';
+ write(interactive_fd, buf, p-buf);
+ }
+ tcsetpgrp(interactive_fd, saved_tty_pgrp);
+ }
+
+ /* Not a signal, just exit */
+ if (sig <= 0)
+ _exit(- sig);
+
+ /* Enable only this sig and kill ourself with it */
+ signal(sig, SIG_DFL);
+ sigdelset(&block_all, sig);
+ sigprocmask(SIG_SETMASK, &block_all, NULL);
+ raise(sig);
+ _exit(1); /* Should not reach it */
+}
+
+/* Restores tty foreground process group, and exits. */
+static void hush_exit(int exitcode) ATTRIBUTE_NORETURN;
+static void hush_exit(int exitcode)
+{
+ fflush(NULL); /* flush all streams */
+ sigexit(- (exitcode & 0xff));
+}
+
+/* Signals are grouped, we handle them in batches */
+static void set_fatal_sighandler(void (*handler)(int))
+{
+ signal(SIGILL , handler);
+ signal(SIGTRAP, handler);
+ signal(SIGABRT, handler);
+ signal(SIGFPE , handler);
+ signal(SIGBUS , handler);
+ signal(SIGSEGV, handler);
+ /* bash 3.2 seems to handle these just like 'fatal' ones,
+ * but _without_ printing signal name. TODO: mimic this too? */
+ signal(SIGHUP , handler);
+ signal(SIGPIPE, handler);
+ signal(SIGALRM, handler);
+}
+static void set_jobctrl_sighandler(void (*handler)(int))
+{
+ signal(SIGTSTP, handler);
+ signal(SIGTTIN, handler);
+ signal(SIGTTOU, handler);
+}
+static void set_misc_sighandler(void (*handler)(int))
+{
+ signal(SIGINT , handler);
+ signal(SIGQUIT, handler);
+ signal(SIGTERM, handler);
+}
+/* SIGCHLD is special and handled separately */
+
static const char *set_cwd(void)
{
if (cwd == bb_msg_unknown)
@@ -493,13 +572,15 @@ static int builtin_exec(struct child_prog *child)
/* built-in 'exit' handler */
static int builtin_exit(struct child_prog *child)
{
- /* bash prints "exit\n" here, then: */
+// TODO: bash does it ONLY on top-level sh exit (+interacive only?)
+ //puts("exit"); /* bash does it */
+
if (child->argv[1] == NULL)
- exit(last_return_code);
+ hush_exit(last_return_code);
/* mimic bash: exit 123abc == exit 255 + error msg */
xfunc_error_retval = 255;
/* bash: exit -2 == exit 254, no error msg */
- exit(xatoi(child->argv[1]));
+ hush_exit(xatoi(child->argv[1]));
}
/* built-in 'export VAR=value' handler */
@@ -555,7 +636,7 @@ static int builtin_fg_bg(struct child_prog *child)
int i, jobnum;
struct pipe *pi;
- if (!interactive)
+ if (!interactive_fd)
return EXIT_FAILURE;
/* If they gave us no args, assume they want the last backgrounded task */
if (!child->argv[1]) {
@@ -581,7 +662,7 @@ static int builtin_fg_bg(struct child_prog *child)
found:
if (*child->argv[0] == 'f') {
/* Put the job into the foreground. */
- tcsetpgrp(shell_terminal, pi->pgrp);
+ tcsetpgrp(interactive_fd, pi->pgrp);
}
/* Restart the processes in the job */
@@ -915,8 +996,8 @@ static int file_get(struct in_str *i)
} else {
/* need to double check i->file because we might be doing something
* more complicated by now, like sourcing or substituting. */
- if (i->__promptme && interactive && i->file == stdin) {
- while (!i->p || !(interactive && strlen(i->p))) {
+ if (i->__promptme && interactive_fd && i->file == stdin) {
+ while (!i->p || !(interactive_fd && strlen(i->p))) {
get_user_input(i);
}
i->promptmode = 2;
@@ -1116,7 +1197,7 @@ static void pseudo_exec(struct child_prog *child)
if (child->group) {
debug_printf("runtime nesting to group\n");
- interactive = 0; /* crucial!!!! */
+ interactive_fd = 0; /* crucial!!!! */
rcode = run_list_real(child->group);
/* OK to leak memory by not calling free_pipe_list,
* since this process is about to exit */
@@ -1203,25 +1284,39 @@ static int checkjobs(struct pipe* fg_pipe)
int prognum = 0;
struct pipe *pi;
pid_t childpid;
+ int rcode = 0;
attributes = WUNTRACED;
+//WUNTRACED?? huh, what will happed on Ctrl-Z? fg waiting code
+//doesn't seem to be ready for stopped children! (only exiting ones)...
if (fg_pipe == NULL) {
attributes |= WNOHANG;
}
+ wait_more:
while ((childpid = waitpid(-1, &status, attributes)) > 0) {
+ /* Were we asked to wait for fg pipe? */
if (fg_pipe) {
- int i, rcode = 0;
+ int i;
for (i = 0; i < fg_pipe->num_progs; i++) {
if (fg_pipe->progs[i].pid == childpid) {
+ /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
+ fg_pipe->progs[i].pid = 0;
if (i == fg_pipe->num_progs-1)
+ /* last process gives overall exitstatus */
rcode = WEXITSTATUS(status);
- fg_pipe->num_progs--;
- return rcode;
+ if (--fg_pipe->running_progs <= 0)
+ /* All processes in fg pipe have exited */
+ return rcode;
+ /* There are still running processes in the fg pipe */
+ goto wait_more;
}
}
}
+ /* 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) {
prognum = 0;
while (prognum < pi->num_progs) {
@@ -1257,9 +1352,9 @@ static int checkjobs(struct pipe* fg_pipe)
bb_perror_msg("waitpid");
/* move the shell to the foreground */
- //if (interactive && tcsetpgrp(shell_terminal, getpgid(0)))
+ //if (interactive_fd && tcsetpgrp(interactive_fd, getpgid(0)))
// bb_perror_msg("tcsetpgrp-2");
- return -1;
+ return rcode;
}
/* run_pipe_real() starts all the jobs, but doesn't wait for anything
@@ -1376,6 +1471,8 @@ static int run_pipe_real(struct pipe *pi)
}
#if ENABLE_FEATURE_SH_STANDALONE
{
+// FIXME: applet runs like part of shell - for example, it ignores
+// SIGINT! Try to Ctrl-C out of "rm -i"... doesn't work
const struct bb_applet *a = find_applet_by_name(child->argv[i]);
if (a && a->nofork) {
setup_redirects(child, squirrel);
@@ -1387,6 +1484,11 @@ static int run_pipe_real(struct pipe *pi)
#endif
}
+ /* Disable job control signals for shell (parent) and
+ * for initial child code after fork */
+ set_jobctrl_sighandler(SIG_IGN);
+
+ pi->running_progs = 0;
for (i = 0; i < pi->num_progs; i++) {
child = &(pi->progs[i]);
@@ -1406,18 +1508,22 @@ static int run_pipe_real(struct pipe *pi)
#else
child->pid = vfork();
#endif
- if (!child->pid) {
- /* Set the handling for job control signals back to the default. */
- signal(SIGINT, SIG_DFL);
- signal(SIGQUIT, SIG_DFL);
- signal(SIGTERM, SIG_DFL);
- signal(SIGTSTP, SIG_DFL);
- signal(SIGTTIN, SIG_DFL);
- signal(SIGTTOU, SIG_DFL);
- signal(SIGCHLD, SIG_DFL);
+ if (!child->pid) { /* child */
+ /* Every child adds itself to new process group
+ * with pgid == pid of first child in pipe */
+ if (interactive_fd) {
+ if (pi->pgrp < 0) /* true for 1st process only */
+ pi->pgrp = getpid();
+ if (setpgid(0, pi->pgrp) == 0 && pi->followup != PIPE_BG) {
+ /* We do it in *every* child, not just first,
+ * to avoid races */
+ tcsetpgrp(interactive_fd, pi->pgrp);
+ }
+ /* Don't do pgrp restore anymore on fatal signals */
+ set_fatal_sighandler(SIG_DFL);
+ }
close_all();
-
if (nextin != 0) {
dup2(nextin, 0);
close(nextin);
@@ -1429,33 +1535,28 @@ static int run_pipe_real(struct pipe *pi)
if (pipefds[0] != -1) {
close(pipefds[0]); /* opposite end of our output pipe */
}
-
/* Like bash, explicit redirects override pipes,
* and the pipe fd is available for dup'ing. */
setup_redirects(child, NULL);
- if (interactive && pi->followup != PIPE_BG) {
- /* If we (the child) win the race, put ourselves in the process
- * group whose leader is the first process in this pipe. */
- if (pi->pgrp < 0) {
- pi->pgrp = getpid();
- }
- if (setpgid(0, pi->pgrp) == 0) {
- tcsetpgrp(2, pi->pgrp);
- }
- }
-
+ /* Restore default handlers just prior to exec */
+ set_jobctrl_sighandler(SIG_DFL);
+ set_misc_sighandler(SIG_DFL);
+ signal(SIGCHLD, SIG_DFL);
pseudo_exec(child);
}
- /* put our child in the process group whose leader is the
- first process in this pipe */
- if (pi->pgrp < 0) {
+ pi->running_progs++;
+
+ /* Second and next children need to know ipd of first one */
+ if (pi->pgrp < 0)
pi->pgrp = child->pid;
- }
+
/* Don't check for errors. The child may be dead already,
* in which case setpgid returns error code EACCES. */
- setpgid(child->pid, pi->pgrp);
+ //why we do it at all?? child does it itself
+ //if (interactive_fd)
+ // setpgid(child->pid, pi->pgrp);
if (nextin != 0)
close(nextin);
@@ -1580,14 +1681,14 @@ static int run_list_real(struct pipe *pi)
insert_bg_job(pi);
rcode = EXIT_SUCCESS;
} else {
- if (interactive) {
- /* move the new process group into the foreground */
- if (tcsetpgrp(shell_terminal, pi->pgrp) && errno != ENOTTY)
- bb_perror_msg("tcsetpgrp-3");
+ if (interactive_fd) {
+ pid_t p;
rcode = checkjobs(pi);
/* move the shell to the foreground */
- if (tcsetpgrp(shell_terminal, getpgid(0)) && errno != ENOTTY)
+ p = getpgid(0);
+ if (tcsetpgrp(interactive_fd, p) && errno != ENOTTY)
bb_perror_msg("tcsetpgrp-4");
+ debug_printf("getpgid(0)=%d\n", (int)p);
} else {
rcode = checkjobs(pi);
}
@@ -2660,28 +2761,33 @@ static int parse_file_outer(FILE *f)
* we don't fight over who gets the foreground */
static void setup_job_control(void)
{
- /*static --why?? */ pid_t shell_pgrp;
+ pid_t shell_pgrp;
+
+ fcntl(interactive_fd, F_SETFD, FD_CLOEXEC);
/* Loop until we are in the foreground. */
- while (tcgetpgrp(shell_terminal) != (shell_pgrp = getpgrp()))
+ while (1) {
+ shell_pgrp = getpgrp();
+ if (tcgetpgrp(interactive_fd) == shell_pgrp)
+ break;
+// and this does... what? need a comment here
kill(- shell_pgrp, SIGTTIN);
+ }
+
+ /* Ignore job-control and misc signals. */
+ set_jobctrl_sighandler(SIG_IGN);
+ set_misc_sighandler(SIG_IGN);
+//huh? signal(SIGCHLD, SIG_IGN);
- /* Ignore interactive and job-control signals. */
- signal(SIGINT, SIG_IGN);
- signal(SIGQUIT, SIG_IGN);
- signal(SIGTERM, SIG_IGN);
- signal(SIGTSTP, SIG_IGN);
- signal(SIGTTIN, SIG_IGN);
- signal(SIGTTOU, SIG_IGN);
- signal(SIGCHLD, SIG_IGN);
+ /* We _must_ do cleanup on fatal signals */
+ set_fatal_sighandler(sigexit);
/* Put ourselves in our own process group. */
- setsid();
shell_pgrp = getpid();
- setpgid(shell_pgrp, shell_pgrp);
+ setpgrp(); /* is the same as setpgid(shell_pgrp, shell_pgrp); */
/* Grab control of the terminal. */
- tcsetpgrp(shell_terminal, shell_pgrp);
+ tcsetpgrp(interactive_fd, shell_pgrp);
}
int hush_main(int argc, char **argv);
@@ -2705,7 +2811,7 @@ int hush_main(int argc, char **argv)
ifs = NULL;
/* map[] is taken care of with call to update_ifs_map() */
fake_mode = 0;
- interactive = 0;
+ interactive_fd = 0;
close_me_head = NULL;
last_bg_pid = 0;
job_list = NULL;
@@ -2747,7 +2853,7 @@ int hush_main(int argc, char **argv)
opt = parse_string_outer(optarg, FLAG_PARSE_SEMICOLON);
goto final_return;
case 'i':
- interactive++;
+ /*interactive_fd++;*/ //huh??
break;
case 'f':
fake_mode++;
@@ -2772,11 +2878,25 @@ int hush_main(int argc, char **argv)
if (argv[optind] == NULL && input == stdin
&& isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
) {
- interactive++;
+ saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
+ debug_printf("saved_tty_pgrp=%d\n", saved_tty_pgrp);
+ if (saved_tty_pgrp >= 0) {
+ saved_task_pgrp = getpgrp();
+ debug_printf("saved_task_pgrp=%d\n", saved_task_pgrp);
+ /* try to dup to high fd#, >= 255 */
+ interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
+ if (interactive_fd < 0) {
+ /* try to dup to any fd */
+ interactive_fd = dup(STDIN_FILENO);
+ if (interactive_fd < 0)
+ /* give up */
+ interactive_fd = 0;
+ }
+ }
}
- debug_printf("\ninteractive=%d\n", interactive);
- if (interactive) {
+ debug_printf("\ninteractive_fd=%d\n", interactive_fd);
+ if (interactive_fd) {
/* Looks like they want an interactive shell */
#if !ENABLE_FEATURE_SH_EXTRA_QUIET
printf( "\n\n%s hush - the humble shell v0.01 (testing)\n",
@@ -2784,6 +2904,12 @@ int hush_main(int argc, char **argv)
printf( "Enter 'help' for a list of built-in commands.\n\n");
#endif
setup_job_control();
+ /* Make xfuncs do cleanup on exit */
+ die_sleep = -1; /* flag */
+ if (setjmp(die_jmp)) {
+ /* xfunc has failed! die die die */
+ hush_exit(xfunc_error_retval);
+ }
}
if (argv[optind] == NULL) {
@@ -2815,7 +2941,7 @@ int hush_main(int argc, char **argv)
#endif
final_return:
- return opt ? opt : last_return_code;
+ hush_exit(opt ? opt : last_return_code);
}
static char *insert_var_value(char *inp)