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hush: fix NOMMU hangs in pseudo_exec_argv. Add forgotted setting

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of signal mask. Reuse same help string in all shells.

function                                             old     new   delta
builtin_exit                                          49      47      -2
pseudo_exec_argv                                     149     145      -4
builtin_help                                          74      63     -11
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-17)             Total: -17 bytes
   text    data     bss     dec     hex filename
 825379     476    7616  833471   cb7bf busybox_old
 825341     476    7616  833433   cb799 busybox_unstripped
This commit is contained in:
Denis Vlasenko 2009-04-04 20:24:37 +00:00
parent 552433bc5a
commit 34d4d89b2d
4 changed files with 74 additions and 63 deletions
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4
shell/ash.c
View File

@ -12230,7 +12230,9 @@ helpcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
unsigned col; unsigned col;
unsigned i; unsigned i;
out1fmt("\nBuilt-in commands:\n-------------------\n"); out1fmt("\n"
"Built-in commands:\n"
"------------------\n");
for (col = 0, i = 0; i < ARRAY_SIZE(builtintab); i++) { for (col = 0, i = 0; i < ARRAY_SIZE(builtintab); i++) {
col += out1fmt("%c%s", ((col == 0) ? '\t' : ' '), col += out1fmt("%c%s", ((col == 0) ? '\t' : ' '),
builtintab[i].name + 1); builtintab[i].name + 1);

122
shell/hush.c
View File

@ -363,11 +363,13 @@ struct parse_context {
/* bitmask of FLAG_xxx, for figuring out valid reserved words */ /* bitmask of FLAG_xxx, for figuring out valid reserved words */
int old_flag; int old_flag;
/* group we are enclosed in: /* group we are enclosed in:
* example 1: "{ { false; ..." * example: "if pipe1; pipe2; then pipe3; fi"
* example 2: "if true; then { false; ..." * when we see "if" or "then", we malloc and copy current context,
* example 3: "if true; then if false; ..." * and make ->stack point to it. then we parse pipeN.
* when we find closing "}" / "fi" / whatever, we move list_head * when closing "then" / fi" / whatever is found,
* into stack->command->group and delete ourself. * we move list_head into ->stack->command->group,
* copy ->stack into current context, and delete ->stack.
* (parsing of { list } and ( list ) doesn't use this method)
*/ */
struct parse_context *stack; struct parse_context *stack;
#endif #endif
@ -532,7 +534,6 @@ static int builtin_wait(char **argv);
static int builtin_break(char **argv); static int builtin_break(char **argv);
static int builtin_continue(char **argv); static int builtin_continue(char **argv);
#endif #endif
//static int builtin_not_written(char **argv);
/* Table of built-in functions. They can be forked or not, depending on /* Table of built-in functions. They can be forked or not, depending on
* context: within pipes, they fork. As simple commands, they do not. * context: within pipes, they fork. As simple commands, they do not.
@ -554,42 +555,44 @@ struct built_in_command {
/* For now, echo and test are unconditionally enabled. /* For now, echo and test are unconditionally enabled.
* Maybe make it configurable? */ * Maybe make it configurable? */
static const struct built_in_command bltins[] = { static const struct built_in_command bltins[] = {
BLTIN("." , builtin_source, "Run commands in a file"), BLTIN("." , builtin_source , "Run commands in a file"),
BLTIN(":" , builtin_true, "No-op"), BLTIN(":" , builtin_true , "No-op"),
BLTIN("[" , builtin_test, "Test condition"), BLTIN("[" , builtin_test , "Test condition"),
#if ENABLE_HUSH_JOB #if ENABLE_HUSH_JOB
BLTIN("bg" , builtin_fg_bg, "Resume a job in the background"), BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"),
#endif #endif
#if ENABLE_HUSH_LOOPS #if ENABLE_HUSH_LOOPS
BLTIN("break" , builtin_break, "Exit from a loop"), BLTIN("break" , builtin_break , "Exit from a loop"),
#endif #endif
BLTIN("cd" , builtin_cd, "Change directory"), BLTIN("cd" , builtin_cd , "Change directory"),
#if ENABLE_HUSH_LOOPS #if ENABLE_HUSH_LOOPS
BLTIN("continue", builtin_continue, "Start new loop iteration"), BLTIN("continue", builtin_continue, "Start new loop iteration"),
#endif #endif
BLTIN("echo" , builtin_echo, "Write to stdout"), BLTIN("echo" , builtin_echo , "Write to stdout"),
BLTIN("eval" , builtin_eval, "Construct and run shell command"), BLTIN("eval" , builtin_eval , "Construct and run shell command"),
BLTIN("exec" , builtin_exec, "Execute command, don't return to shell"), BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"),
BLTIN("exit" , builtin_exit, "Exit"), BLTIN("exit" , builtin_exit , "Exit"),
BLTIN("export", builtin_export, "Set environment variable"), BLTIN("export" , builtin_export , "Set environment variable"),
#if ENABLE_HUSH_JOB #if ENABLE_HUSH_JOB
BLTIN("fg" , builtin_fg_bg, "Bring job into the foreground"), BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"),
BLTIN("jobs" , builtin_jobs, "List active jobs"),
#endif #endif
BLTIN("pwd" , builtin_pwd, "Print current directory"),
BLTIN("read" , builtin_read, "Input environment variable"),
// BLTIN("return", builtin_not_written, "Return from a function"),
BLTIN("set" , builtin_set, "Set/unset shell local variables"),
BLTIN("shift" , builtin_shift, "Shift positional parameters"),
BLTIN("test" , builtin_test, "Test condition"),
BLTIN("trap" , builtin_trap, "Trap signals"),
// BLTIN("ulimit", builtin_not_written, "Control resource limits"),
BLTIN("umask" , builtin_umask, "Set file creation mask"),
BLTIN("unset" , builtin_unset, "Unset environment variable"),
BLTIN("wait" , builtin_wait, "Wait for process"),
#if ENABLE_HUSH_HELP #if ENABLE_HUSH_HELP
BLTIN("help" , builtin_help, "List shell built-in commands"), BLTIN("help" , builtin_help , "List shell built-in commands"),
#endif #endif
#if ENABLE_HUSH_JOB
BLTIN("jobs" , builtin_jobs , "List active jobs"),
#endif
BLTIN("pwd" , builtin_pwd , "Print current directory"),
BLTIN("read" , builtin_read , "Input environment variable"),
// BLTIN("return" , builtin_return , "Return from a function"),
BLTIN("set" , builtin_set , "Set/unset shell local variables"),
BLTIN("shift" , builtin_shift , "Shift positional parameters"),
BLTIN("test" , builtin_test , "Test condition"),
BLTIN("trap" , builtin_trap , "Trap signals"),
// BLTIN("ulimit" , builtin_return , "Control resource limits"),
BLTIN("umask" , builtin_umask , "Set file creation mask"),
BLTIN("unset" , builtin_unset , "Unset environment variable"),
BLTIN("wait" , builtin_wait , "Wait for process"),
}; };
@ -2117,7 +2120,7 @@ static void restore_redirects(int squirrel[])
#endif #endif
static void free_pipe_list(struct pipe *head, int indent); static void free_pipe_list(struct pipe *head, int indent);
/* return code is the exit status of the pipe */ /* Return code is the exit status of the pipe */
static void free_pipe(struct pipe *pi, int indent) static void free_pipe(struct pipe *pi, int indent)
{ {
char **p; char **p;
@ -2125,7 +2128,7 @@ static void free_pipe(struct pipe *pi, int indent)
struct redir_struct *r, *rnext; struct redir_struct *r, *rnext;
int a, i; int a, i;
if (pi->stopped_cmds > 0) if (pi->stopped_cmds > 0) /* why? */
return; return;
debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid()); debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid());
for (i = 0; i < pi->num_cmds; i++) { for (i = 0; i < pi->num_cmds; i++) {
@ -2216,9 +2219,7 @@ static void pseudo_exec_argv(nommu_save_t *nommu_save,
char **new_env; char **new_env;
const struct built_in_command *x; const struct built_in_command *x;
/* If a variable is assigned in a forest, and nobody listens, /* Case when we are here: ... | var=val | ... */
* was it ever really set?
*/
if (!argv[assignment_cnt]) if (!argv[assignment_cnt])
_exit(EXIT_SUCCESS); _exit(EXIT_SUCCESS);
@ -2239,8 +2240,13 @@ static void pseudo_exec_argv(nommu_save_t *nommu_save,
#endif #endif
} }
/* /* On NOMMU, we must never block!
* Check if the command matches any of the builtins. * Example: { sleep 99999 | read line } & echo Ok
* read builtin will block on read syscall, leaving parent blocked
* in vfork. Therefore we can't do this:
*/
#if BB_MMU
/* Check if the command matches any of the builtins.
* Depending on context, this might be redundant. But it's * Depending on context, this might be redundant. But it's
* easier to waste a few CPU cycles than it is to figure out * easier to waste a few CPU cycles than it is to figure out
* if this is one of those cases. * if this is one of those cases.
@ -2249,33 +2255,35 @@ static void pseudo_exec_argv(nommu_save_t *nommu_save,
if (strcmp(argv[0], x->cmd) == 0) { if (strcmp(argv[0], x->cmd) == 0) {
debug_printf_exec("running builtin '%s'\n", argv[0]); debug_printf_exec("running builtin '%s'\n", argv[0]);
rcode = x->function(argv); rcode = x->function(argv);
fflush(stdout); fflush(NULL);
_exit(rcode); _exit(rcode);
} }
} }
#endif
/* Check if the command matches any busybox applets */
#if ENABLE_FEATURE_SH_STANDALONE #if ENABLE_FEATURE_SH_STANDALONE
/* Check if the command matches any busybox applets */
if (strchr(argv[0], '/') == NULL) { if (strchr(argv[0], '/') == NULL) {
int a = find_applet_by_name(argv[0]); int a = find_applet_by_name(argv[0]);
if (a >= 0) { if (a >= 0) {
#if BB_MMU /* see above why on NOMMU it is not allowed */
if (APPLET_IS_NOEXEC(a)) { if (APPLET_IS_NOEXEC(a)) {
debug_printf_exec("running applet '%s'\n", argv[0]); debug_printf_exec("running applet '%s'\n", argv[0]);
// is it ok that run_applet_no_and_exit() does exit(), not _exit()?
run_applet_no_and_exit(a, argv); run_applet_no_and_exit(a, argv);
} }
/* re-exec ourselves with the new arguments */ #endif
/* Re-exec ourselves */
debug_printf_exec("re-execing applet '%s'\n", argv[0]); debug_printf_exec("re-execing applet '%s'\n", argv[0]);
execvp(bb_busybox_exec_path, argv); sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
execv(bb_busybox_exec_path, argv);
/* If they called chroot or otherwise made the binary no longer /* If they called chroot or otherwise made the binary no longer
* executable, fall through */ * executable, fall through */
} }
} }
#endif #endif
sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
debug_printf_exec("execing '%s'\n", argv[0]); debug_printf_exec("execing '%s'\n", argv[0]);
sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
execvp(argv[0], argv); execvp(argv[0], argv);
bb_perror_msg("can't exec '%s'", argv[0]); bb_perror_msg("can't exec '%s'", argv[0]);
_exit(EXIT_FAILURE); _exit(EXIT_FAILURE);
@ -2317,8 +2325,8 @@ static void pseudo_exec(nommu_save_t *nommu_save,
#endif #endif
} }
/* Can happen. See what bash does with ">foo" by itself. */ /* Case when we are here: ... | >file */
debug_printf("pseudo_exec'ed null command\n"); debug_printf_exec("pseudo_exec'ed null command\n");
_exit(EXIT_SUCCESS); _exit(EXIT_SUCCESS);
} }
@ -2569,8 +2577,8 @@ static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
} }
#endif #endif
/* run_pipe() starts all the jobs, but doesn't wait for anything /* Start all the jobs, but don't wait for anything to finish.
* to finish. See checkjobs(). * See checkjobs().
* *
* Return code is normally -1, when the caller has to wait for children * Return code is normally -1, when the caller has to wait for children
* to finish to determine the exit status of the pipe. If the pipe * to finish to determine the exit status of the pipe. If the pipe
@ -2588,7 +2596,7 @@ static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
* cmd || ... { list } || ... * cmd || ... { list } || ...
* If it is, then we can run cmd as a builtin, NOFORK [do we do this?], * If it is, then we can run cmd as a builtin, NOFORK [do we do this?],
* or (if SH_STANDALONE) an applet, and we can run the { list } * or (if SH_STANDALONE) an applet, and we can run the { list }
* with run_list(). Otherwise, we fork and exec cmd. * with run_list(). If it isn't one of these, we fork and exec cmd.
* *
* Cases when we must fork: * Cases when we must fork:
* non-single: cmd | cmd * non-single: cmd | cmd
@ -3771,7 +3779,7 @@ static FILE *generate_stream_from_string(const char *s)
* echo OK * echo OK
*/ */
//TODO: pass non-exported variables, traps, and functions //TODO: pass non-exported variables, traps, and functions
execl(CONFIG_BUSYBOX_EXEC_PATH, "hush", "-c", s, NULL); execl(bb_busybox_exec_path, "hush", "-c", s, NULL);
_exit(127); _exit(127);
#endif #endif
} }
@ -5144,7 +5152,7 @@ static int builtin_fg_bg(char **argv)
found: found:
// TODO: bash prints a string representation // TODO: bash prints a string representation
// of job being foregrounded (like "sleep 1 | cat") // of job being foregrounded (like "sleep 1 | cat")
if (*argv[0] == 'f') { if (argv[0][0] == 'f') {
/* Put the job into the foreground. */ /* Put the job into the foreground. */
tcsetpgrp(G_interactive_fd, pi->pgrp); tcsetpgrp(G_interactive_fd, pi->pgrp);
} }
@ -5162,12 +5170,11 @@ static int builtin_fg_bg(char **argv)
if (errno == ESRCH) { if (errno == ESRCH) {
delete_finished_bg_job(pi); delete_finished_bg_job(pi);
return EXIT_SUCCESS; return EXIT_SUCCESS;
} else {
bb_perror_msg("kill (SIGCONT)");
} }
bb_perror_msg("kill (SIGCONT)");
} }
if (*argv[0] == 'f') { if (argv[0][0] == 'f') {
remove_bg_job(pi); remove_bg_job(pi);
return checkjobs_and_fg_shell(pi); return checkjobs_and_fg_shell(pi);
} }
@ -5180,8 +5187,9 @@ static int builtin_help(char **argv UNUSED_PARAM)
{ {
const struct built_in_command *x; const struct built_in_command *x;
printf("\nBuilt-in commands:\n"); printf("\n"
printf("-------------------\n"); "Built-in commands:\n"
"------------------\n");
for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) { for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
printf("%s\t%s\n", x->cmd, x->descr); printf("%s\t%s\n", x->cmd, x->descr);
} }

5
shell/lash_unused.c
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@ -312,8 +312,9 @@ static int builtin_help(struct child_prog UNUSED_PARAM *dummy)
{ {
const struct built_in_command *x; const struct built_in_command *x;
printf("\nBuilt-in commands:\n" printf("\n"
"-------------------\n"); "Built-in commands:\n"
"------------------\n");
for (x = bltins; x <= &VEC_LAST(bltins); x++) { for (x = bltins; x <= &VEC_LAST(bltins); x++) {
if (x->descr == NULL) if (x->descr == NULL)
continue; continue;

6
shell/msh.c
View File

@ -35,7 +35,6 @@
# include <assert.h> # include <assert.h>
# define bb_dev_null "/dev/null" # define bb_dev_null "/dev/null"
# define DEFAULT_SHELL "/proc/self/exe" # define DEFAULT_SHELL "/proc/self/exe"
# define CONFIG_BUSYBOX_EXEC_PATH "/proc/self/exe"
# define bb_banner "busybox standalone" # define bb_banner "busybox standalone"
# define ENABLE_FEATURE_SH_STANDALONE 0 # define ENABLE_FEATURE_SH_STANDALONE 0
# define bb_msg_memory_exhausted "memory exhausted" # define bb_msg_memory_exhausted "memory exhausted"
@ -3176,8 +3175,9 @@ static int dohelp(struct op *t UNUSED_PARAM, char **args UNUSED_PARAM)
int col; int col;
const struct builtincmd *x; const struct builtincmd *x;
puts("\nBuilt-in commands:\n" printf("\n"
"-------------------"); "Built-in commands:\n"
"------------------\n");
col = 0; col = 0;
x = builtincmds; x = builtincmds;