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busybox/shell/hush.c
Eric Andersen 83a2ae2184 More hush updates from Larry: 
Update some comments.  Generate partial placeholders for the missing
    builtins.  Write builtin_umask.  Properly treat exec without arguments
    as a means to open/close files within the running script.  Implement
    "4<&-" that encodes for file descriptor closure.
2001-05-07 17:59:25 +00:00

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/* vi: set sw=4 ts=4: */
/*
* sh.c -- a prototype Bourne shell grammar parser
* Intended to follow the original Thompson and Ritchie
* "small and simple is beautiful" philosophy, which
* incidentally is a good match to today's BusyBox.
*
* Copyright (C) 2000,2001 Larry Doolittle <larry@doolittle.boa.org>
*
* Credits:
* The parser routines proper are all original material, first
* written Dec 2000 and Jan 2001 by Larry Doolittle.
* The execution engine, the builtins, and much of the underlying
* support has been adapted from busybox-0.49pre's lash,
* which is Copyright (C) 2000 by Lineo, Inc., and
* written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>.
* That, in turn, is based in part on ladsh.c, by Michael K. Johnson and
* Erik W. Troan, which they placed in the public domain. I don't know
* how much of the Johnson/Troan code has survived the repeated rewrites.
* Other credits:
* simple_itoa() was lifted from boa-0.93.15
* b_addchr() derived from similar w_addchar function in glibc-2.2
* setup_redirect(), redirect_opt_num(), and big chunks of main()
* and many builtins derived from contributions by Erik Andersen
* miscellaneous bugfixes from Matt Kraai
*
* There are two big (and related) architecture differences between
* this parser and the lash parser. One is that this version is
* actually designed from the ground up to understand nearly all
* of the Bourne grammar. The second, consequential change is that
* the parser and input reader have been turned inside out. Now,
* the parser is in control, and asks for input as needed. The old
* way had the input reader in control, and it asked for parsing to
* take place as needed. The new way makes it much easier to properly
* handle the recursion implicit in the various substitutions, especially
* across continuation lines.
*
* Bash grammar not implemented: (how many of these were in original sh?)
* $@ (those sure look like weird quoting rules)
* $_
* ! negation operator for pipes
* &> and >& redirection of stdout+stderr
* Brace Expansion
* Tilde Expansion
* fancy forms of Parameter Expansion
* Arithmetic Expansion
* <(list) and >(list) Process Substitution
* reserved words: case, esac, select, function
* Here Documents ( << word )
* Functions
* Major bugs:
* job handling woefully incomplete and buggy
* reserved word execution woefully incomplete and buggy
* to-do:
* port selected bugfixes from post-0.49 busybox lash - done?
* finish implementing reserved words: for, while, until, do, done
* change { and } from special chars to reserved words
* builtins: break, continue, eval, return, set, trap, ulimit
* test magic exec
* handle children going into background
* clean up recognition of null pipes
* have builtin_exec set flag to avoid restore_redirects
* check setting of global_argc and global_argv
* control-C handling, probably with longjmp
* VAR=value prefix for simple commands
* follow IFS rules more precisely, including update semantics
* figure out what to do with backslash-newline
* explain why we use signal instead of sigaction
* propagate syntax errors, die on resource errors?
* continuation lines, both explicit and implicit - done?
* memory leak finding and plugging - done?
* more testing, especially quoting rules and redirection
* maybe change map[] to use 2-bit entries
* (eventually) remove all the printf's
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <ctype.h> /* isalpha, isdigit */
#include <unistd.h> /* getpid */
#include <stdlib.h> /* getenv, atoi */
#include <string.h> /* strchr */
#include <stdio.h> /* popen etc. */
#include <glob.h> /* glob, of course */
#include <stdarg.h> /* va_list */
#include <errno.h>
#include <fcntl.h>
#include <getopt.h> /* should be pretty obvious */
#include <sys/stat.h> /* ulimit */
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
/* #include <dmalloc.h> */
/* #define DEBUG_SHELL */
#ifdef BB_VER
#include "busybox.h"
#include "cmdedit.h"
#else
#define applet_name "hush"
#include "standalone.h"
#define shell_main main
#define BB_FEATURE_SH_SIMPLE_PROMPT
#endif
typedef enum {
REDIRECT_INPUT = 1,
REDIRECT_OVERWRITE = 2,
REDIRECT_APPEND = 3,
REDIRECT_HEREIS = 4,
REDIRECT_IO = 5
} redir_type;
/* The descrip member of this structure is only used to make debugging
* output pretty */
struct {int mode; int default_fd; char *descrip;} redir_table[] = {
{ 0, 0, "()" },
{ O_RDONLY, 0, "<" },
{ O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
{ O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
{ O_RDONLY, -1, "<<" },
{ O_RDWR, 1, "<>" }
};
typedef enum {
PIPE_SEQ = 1,
PIPE_AND = 2,
PIPE_OR = 3,
PIPE_BG = 4,
} pipe_style;
/* might eventually control execution */
typedef enum {
RES_NONE = 0,
RES_IF = 1,
RES_THEN = 2,
RES_ELIF = 3,
RES_ELSE = 4,
RES_FI = 5,
RES_FOR = 6,
RES_WHILE = 7,
RES_UNTIL = 8,
RES_DO = 9,
RES_DONE = 10,
RES_XXXX = 11,
RES_SNTX = 12
} reserved_style;
#define FLAG_END (1<<RES_NONE)
#define FLAG_IF (1<<RES_IF)
#define FLAG_THEN (1<<RES_THEN)
#define FLAG_ELIF (1<<RES_ELIF)
#define FLAG_ELSE (1<<RES_ELSE)
#define FLAG_FI (1<<RES_FI)
#define FLAG_FOR (1<<RES_FOR)
#define FLAG_WHILE (1<<RES_WHILE)
#define FLAG_UNTIL (1<<RES_UNTIL)
#define FLAG_DO (1<<RES_DO)
#define FLAG_DONE (1<<RES_DONE)
#define FLAG_START (1<<RES_XXXX)
/* This holds pointers to the various results of parsing */
struct p_context {
struct child_prog *child;
struct pipe *list_head;
struct pipe *pipe;
struct redir_struct *pending_redirect;
reserved_style w;
int old_flag; /* for figuring out valid reserved words */
struct p_context *stack;
/* How about quoting status? */
};
struct redir_struct {
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 */
};
struct child_prog {
pid_t pid; /* 0 if exited */
char **argv; /* program name and arguments */
struct pipe *group; /* if non-NULL, first in group or subshell */
int subshell; /* flag, non-zero if group must be forked */
struct redir_struct *redirects; /* I/O redirections */
glob_t glob_result; /* result of parameter globbing */
int is_stopped; /* is the program currently running? */
struct pipe *family; /* pointer back to the child's parent pipe */
};
struct pipe {
int jobid; /* job number */
int num_progs; /* total number of programs in job */
int running_progs; /* number of programs running */
char *text; /* name of job */
char *cmdbuf; /* buffer various argv's point into */
pid_t pgrp; /* process group ID for the job */
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 */
reserved_style r_mode; /* supports if, for, while, until */
};
struct jobset {
struct pipe *head; /* head of list of running jobs */
struct pipe *fg; /* current foreground job */
};
struct close_me {
int fd;
struct close_me *next;
};
/* globals, connect us to the outside world
* the first three support $?, $#, and $1 */
char **global_argv;
unsigned int global_argc;
unsigned int last_return_code;
extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
/* Variables we export */
unsigned int shell_context; /* Used in cmdedit.c to reset the
* context when someone hits ^C */
/* "globals" within this file */
static char *ifs=NULL;
static char map[256];
static int fake_mode=0;
static int interactive=0;
static struct close_me *close_me_head = NULL;
static char *cwd;
static struct jobset *job_list;
static unsigned int last_bg_pid=0;
static char *PS1;
static char *PS2 = "> ";
#define B_CHUNK (100)
#define B_NOSPAC 1
#define MAX_LINE 256 /* for cwd */
#define MAX_READ 256 /* for builtin_read */
typedef struct {
char *data;
int length;
int maxlen;
int quote;
int nonnull;
} o_string;
#define NULL_O_STRING {NULL,0,0,0,0}
/* used for initialization:
o_string foo = NULL_O_STRING; */
/* I can almost use ordinary FILE *. Is open_memstream() universally
* available? Where is it documented? */
struct in_str {
const char *p;
int __promptme;
int promptmode;
FILE *file;
int (*get) (struct in_str *);
int (*peek) (struct in_str *);
};
#define b_getch(input) ((input)->get(input))
#define b_peek(input) ((input)->peek(input))
#define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
struct built_in_command {
char *cmd; /* name */
char *descr; /* description */
int (*function) (struct child_prog *); /* function ptr */
};
/* belongs in busybox.h */
static inline int max(int a, int b) {
return (a>b)?a:b;
}
/* This should be in utility.c */
#ifdef DEBUG_SHELL
static void debug_printf(const char *format, ...)
{
va_list args;
va_start(args, format);
vfprintf(stderr, format, args);
va_end(args);
}
#else
static void debug_printf(const char *format, ...) { }
#endif
#define final_printf debug_printf
void __syntax(char *file, int line) {
fprintf(stderr,"syntax error %s:%d\n",file,line);
}
#define syntax() __syntax(__FILE__, __LINE__)
/* Index of subroutines: */
/* function prototypes for builtins */
static int builtin_cd(struct child_prog *child);
static int builtin_env(struct child_prog *child);
static int builtin_exec(struct child_prog *child);
static int builtin_exit(struct child_prog *child);
static int builtin_export(struct child_prog *child);
static int builtin_fg_bg(struct child_prog *child);
static int builtin_help(struct child_prog *child);
static int builtin_jobs(struct child_prog *child);
static int builtin_pwd(struct child_prog *child);
static int builtin_read(struct child_prog *child);
static int builtin_shift(struct child_prog *child);
static int builtin_source(struct child_prog *child);
static int builtin_umask(struct child_prog *child);
static int builtin_unset(struct child_prog *child);
static int builtin_not_written(struct child_prog *child);
/* o_string manipulation: */
static int b_check_space(o_string *o, int len);
static int b_addchr(o_string *o, int ch);
static void b_reset(o_string *o);
static int b_addqchr(o_string *o, int ch, int quote);
static int b_adduint(o_string *o, unsigned int i);
/* in_str manipulations: */
static int static_get(struct in_str *i);
static int static_peek(struct in_str *i);
static int file_get(struct in_str *i);
static int file_peek(struct in_str *i);
static void setup_file_in_str(struct in_str *i, FILE *f);
static void setup_string_in_str(struct in_str *i, const char *s);
/* close_me manipulations: */
static void mark_open(int fd);
static void mark_closed(int fd);
static void close_all();
/* "run" the final data structures: */
static char *indenter(int i);
static int run_list_test(struct pipe *head, int indent);
static int run_pipe_test(struct pipe *pi, int indent);
/* really run the final data structures: */
static int setup_redirects(struct child_prog *prog, int squirrel[]);
static int pipe_wait(struct pipe *pi);
static int run_list_real(struct pipe *pi);
static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn));
static int run_pipe_real(struct pipe *pi);
/* extended glob support: */
static int globhack(const char *src, int flags, glob_t *pglob);
static int glob_needed(const char *s);
static int xglob(o_string *dest, int flags, glob_t *pglob);
/* data structure manipulation: */
static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
static void initialize_context(struct p_context *ctx);
static int done_word(o_string *dest, struct p_context *ctx);
static int done_command(struct p_context *ctx);
static int done_pipe(struct p_context *ctx, pipe_style type);
/* primary string parsing: */
static int redirect_dup_num(struct in_str *input);
static int redirect_opt_num(o_string *o);
static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src);
static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
/* setup: */
static int parse_stream_outer(struct in_str *inp);
static int parse_string_outer(const char *s);
static int parse_file_outer(FILE *f);
/* job management: */
static void checkjobs();
static void insert_bg_job(struct pipe *pi);
static void remove_bg_job(struct pipe *pi);
static void free_pipe(struct pipe *pi);
/* Table of built-in functions. They can be forked or not, depending on
* context: within pipes, they fork. As simple commands, they do not.
* When used in non-forking context, they can change global variables
* in the parent shell process. If forked, of course they can not.
* For example, 'unset foo | whatever' will parse and run, but foo will
* still be set at the end. */
static struct built_in_command bltins[] = {
{"bg", "Resume a job in the background", builtin_fg_bg},
{"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},
{"env", "Print all environment variables", builtin_env},
{"eval", "Construct and run shell command", builtin_not_written},
{"exec", "Exec command, replacing this shell with the exec'd process", builtin_exec},
{"exit", "Exit from shell()", builtin_exit},
{"export", "Set environment variable", builtin_export},
{"fg", "Bring job into the foreground", builtin_fg_bg},
{"jobs", "Lists the active jobs", builtin_jobs},
{"pwd", "Print current directory", builtin_pwd},
{"read", "Input environment variable", builtin_read},
{"return", "Return from a function", builtin_not_written},
{"set", "Set/unset shell options", builtin_not_written},
{"shift", "Shift positional parameters", builtin_shift},
{"trap", "Trap signals", builtin_not_written},
{"ulimit","Controls resource limits", builtin_not_written},
{"umask","Sets file creation mask", builtin_umask},
{"unset", "Unset environment variable", builtin_unset},
{".", "Source-in and run commands in a file", builtin_source},
{"help", "List shell built-in commands", builtin_help},
{NULL, NULL, NULL}
};
/* built-in 'cd <path>' handler */
static int builtin_cd(struct child_prog *child)
{
char *newdir;
if (child->argv[1] == NULL)
newdir = getenv("HOME");
else
newdir = child->argv[1];
if (chdir(newdir)) {
printf("cd: %s: %s\n", newdir, strerror(errno));
return EXIT_FAILURE;
}
getcwd(cwd, sizeof(char)*MAX_LINE);
return EXIT_SUCCESS;
}
/* built-in 'env' handler */
static int builtin_env(struct child_prog *dummy)
{
char **e = environ;
if (e == NULL) return EXIT_FAILURE;
for (; *e; e++) {
puts(*e);
}
return EXIT_SUCCESS;
}
/* built-in 'exec' handler */
static int builtin_exec(struct child_prog *child)
{
if (child->argv[1] == NULL)
return EXIT_SUCCESS; /* Really? */
child->argv++;
pseudo_exec(child);
/* never returns */
}
/* built-in 'exit' handler */
static int builtin_exit(struct child_prog *child)
{
if (child->argv[1] == NULL)
exit(last_return_code);
exit (atoi(child->argv[1]));
}
/* built-in 'export VAR=value' handler */
static int builtin_export(struct child_prog *child)
{
int res;
if (child->argv[1] == NULL) {
return (builtin_env(child));
}
res = putenv(child->argv[1]);
if (res)
fprintf(stderr, "export: %s\n", strerror(errno));
return (res);
}
/* built-in 'fg' and 'bg' handler */
static int builtin_fg_bg(struct child_prog *child)
{
int i, jobnum;
struct pipe *pi=NULL;
/* If they gave us no args, assume they want the last backgrounded task */
if (!child->argv[1]) {
for (pi = job_list->head; pi; pi = pi->next) {
if (pi->progs && pi->progs->pid == last_bg_pid) {
break;
}
}
if (!pi) {
error_msg("%s: no current job", child->argv[0]);
return EXIT_FAILURE;
}
} else {
if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
return EXIT_FAILURE;
}
for (pi = job_list->head; pi; pi = pi->next) {
if (pi->jobid == jobnum) {
break;
}
}
if (!pi) {
error_msg("%s: %d: no such job", child->argv[0], jobnum);
return EXIT_FAILURE;
}
}
if (*child->argv[0] == 'f') {
/* Make this job the foreground job */
signal(SIGTTOU, SIG_IGN);
/* suppress messages when run from /linuxrc mag@sysgo.de */
if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
perror_msg("tcsetpgrp");
signal(SIGTTOU, SIG_DFL);
job_list->fg = pi;
}
/* Restart the processes in the job */
for (i = 0; i < pi->num_progs; i++)
pi->progs[i].is_stopped = 0;
kill(-pi->pgrp, SIGCONT);
pi->stopped_progs = 0;
return EXIT_SUCCESS;
}
/* built-in 'help' handler */
static int builtin_help(struct child_prog *dummy)
{
struct built_in_command *x;
printf("\nBuilt-in commands:\n");
printf("-------------------\n");
for (x = bltins; x->cmd; x++) {
if (x->descr==NULL)
continue;
printf("%s\t%s\n", x->cmd, x->descr);
}
printf("\n\n");
return EXIT_SUCCESS;
}
/* built-in 'jobs' handler */
static int builtin_jobs(struct child_prog *child)
{
struct pipe *job;
char *status_string;
for (job = job_list->head; job; job = job->next) {
if (job->running_progs == job->stopped_progs)
status_string = "Stopped";
else
status_string = "Running";
printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
}
return EXIT_SUCCESS;
}
/* built-in 'pwd' handler */
static int builtin_pwd(struct child_prog *dummy)
{
getcwd(cwd, MAX_LINE);
puts(cwd);
return EXIT_SUCCESS;
}
/* built-in 'read VAR' handler */
static int builtin_read(struct child_prog *child)
{
int res = 0, len, newlen;
char *s;
char string[MAX_READ];
if (child->argv[1]) {
/* argument (VAR) given: put "VAR=" into buffer */
strcpy(string, child->argv[1]);
len = strlen(string);
string[len++] = '=';
string[len] = '\0';
/* XXX would it be better to go through in_str? */
fgets(&string[len], sizeof(string) - len, stdin); /* read string */
newlen = strlen(string);
if(newlen > len)
string[--newlen] = '\0'; /* chomp trailing newline */
/*
** string should now contain "VAR=<value>"
** copy it (putenv() won't do that, so we must make sure
** the string resides in a static buffer!)
*/
res = -1;
if((s = strdup(string)))
res = putenv(s);
if (res)
fprintf(stderr, "read: %s\n", strerror(errno));
}
else
fgets(string, sizeof(string), stdin);
return (res);
}
/* Built-in 'shift' handler */
static int builtin_shift(struct child_prog *child)
{
int n=1;
if (child->argv[1]) {
n=atoi(child->argv[1]);
}
if (n>=0 && n<global_argc) {
/* XXX This probably breaks $0 */
global_argc -= n;
global_argv += n;
return EXIT_SUCCESS;
} else {
return EXIT_FAILURE;
}
}
/* Built-in '.' handler (read-in and execute commands from file) */
static int builtin_source(struct child_prog *child)
{
FILE *input;
int status;
if (child->argv[1] == NULL)
return EXIT_FAILURE;
/* XXX search through $PATH is missing */
input = fopen(child->argv[1], "r");
if (!input) {
fprintf(stderr, "Couldn't open file '%s'\n", child->argv[1]);
return EXIT_FAILURE;
}
/* Now run the file */
/* XXX argv and argc are broken; need to save old global_argv
* (pointer only is OK!) on this stack frame,
* set global_argv=child->argv+1, recurse, and restore. */
mark_open(fileno(input));
status = parse_file_outer(input);
mark_closed(fileno(input));
fclose(input);
return (status);
}
static int builtin_umask(struct child_prog *child)
{
mode_t new_umask;
const char *arg = child->argv[1];
char *end;
if (arg) {
new_umask=strtoul(arg, &end, 8);
if (*end!='\0' || end == arg) {
return EXIT_FAILURE;
}
} else {
printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
}
umask(new_umask);
return EXIT_SUCCESS;
}
/* built-in 'unset VAR' handler */
static int builtin_unset(struct child_prog *child)
{
if (child->argv[1] == NULL) {
fprintf(stderr, "unset: parameter required.\n");
return EXIT_FAILURE;
}
unsetenv(child->argv[1]);
return EXIT_SUCCESS;
}
static int builtin_not_written(struct child_prog *child)
{
printf("builtin_%s not written\n",child->argv[0]);
return EXIT_FAILURE;
}
static int b_check_space(o_string *o, int len)
{
/* It would be easy to drop a more restrictive policy
* in here, such as setting a maximum string length */
if (o->length + len > o->maxlen) {
char *old_data = o->data;
/* assert (data == NULL || o->maxlen != 0); */
o->maxlen += max(2*len, B_CHUNK);
o->data = realloc(o->data, 1 + o->maxlen);
if (o->data == NULL) {
free(old_data);
}
}
return o->data == NULL;
}
static int b_addchr(o_string *o, int ch)
{
debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
if (b_check_space(o, 1)) return B_NOSPAC;
o->data[o->length] = ch;
o->length++;
o->data[o->length] = '\0';
return 0;
}
static void b_reset(o_string *o)
{
o->length = 0;
o->nonnull = 0;
if (o->data != NULL) *o->data = '\0';
}
static void b_free(o_string *o)
{
b_reset(o);
if (o->data != NULL) free(o->data);
o->data = NULL;
o->maxlen = 0;
}
/* My analysis of quoting semantics tells me that state information
* is associated with a destination, not a source.
*/
static int b_addqchr(o_string *o, int ch, int quote)
{
if (quote && strchr("*?[\\",ch)) {
int rc;
rc = b_addchr(o, '\\');
if (rc) return rc;
}
return b_addchr(o, ch);
}
/* belongs in utility.c */
char *simple_itoa(unsigned int i)
{
/* 21 digits plus null terminator, good for 64-bit or smaller ints */
static char local[22];
char *p = &local[21];
*p-- = '\0';
do {
*p-- = '0' + i % 10;
i /= 10;
} while (i > 0);
return p + 1;
}
static int b_adduint(o_string *o, unsigned int i)
{
int r;
char *p = simple_itoa(i);
/* no escape checking necessary */
do r=b_addchr(o, *p++); while (r==0 && *p);
return r;
}
static int static_get(struct in_str *i)
{
int ch=*i->p++;
if (ch=='\0') return EOF;
return ch;
}
static int static_peek(struct in_str *i)
{
return *i->p;
}
static inline void cmdedit_set_initial_prompt(void)
{
#ifdef BB_FEATURE_SH_SIMPLE_PROMPT
PS1 = NULL;
#else
PS1 = getenv("PS1");
if(PS1==0)
PS1 = "\\w \\$ ";
#endif
}
static inline void setup_prompt_string(int promptmode, char **prompt_str)
{
debug_printf("setup_prompt_string %d ",promptmode);
#ifdef BB_FEATURE_SH_SIMPLE_PROMPT
/* Set up the prompt */
if (promptmode == 1) {
if (PS1)
free(PS1);
PS1=xmalloc(strlen(cwd)+4);
sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ? "$ ":"# ");
*prompt_str = PS1;
} else {
*prompt_str = PS2;
}
#else
*prompt_str = (promptmode==0)? PS1 : PS2;
#endif
debug_printf("result %s\n",*prompt_str);
}
static void get_user_input(struct in_str *i)
{
char *prompt_str;
static char the_command[BUFSIZ];
setup_prompt_string(i->promptmode, &prompt_str);
#ifdef BB_FEATURE_COMMAND_EDITING
/*
** enable command line editing only while a command line
** is actually being read; otherwise, we'll end up bequeathing
** atexit() handlers and other unwanted stuff to our
** child processes (rob@sysgo.de)
*/
cmdedit_read_input(prompt_str, the_command);
cmdedit_terminate();
#else
fputs(prompt_str, stdout);
fflush(stdout);
the_command[0]=fgetc(i->file);
the_command[1]='\0';
#endif
i->p = the_command;
}
/* This is the magic location that prints prompts
* and gets data back from the user */
static int file_get(struct in_str *i)
{
int ch;
ch = 0;
/* If there is data waiting, eat it up */
if (i->p && *i->p) {
ch=*i->p++;
} 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) {
get_user_input(i);
i->promptmode=2;
i->__promptme = 0;
if (i->p && *i->p) {
ch=*i->p++;
}
} else {
ch = fgetc(i->file);
}
debug_printf("b_getch: got a %d\n", ch);
}
if (ch == '\n') i->__promptme=1;
return ch;
}
/* All the callers guarantee this routine will never be
* used right after a newline, so prompting is not needed.
*/
static int file_peek(struct in_str *i)
{
if (i->p && *i->p) {
return *i->p;
} else {
static char buffer[2];
buffer[0] = fgetc(i->file);
buffer[1] = '\0';
i->p = buffer;
debug_printf("b_peek: got a %d\n", *i->p);
return *i->p;
}
}
static void setup_file_in_str(struct in_str *i, FILE *f)
{
i->peek = file_peek;
i->get = file_get;
i->__promptme=1;
i->promptmode=1;
i->file = f;
i->p = NULL;
}
static void setup_string_in_str(struct in_str *i, const char *s)
{
i->peek = static_peek;
i->get = static_get;
i->__promptme=1;
i->promptmode=1;
i->p = s;
}
static void mark_open(int fd)
{
struct close_me *new = xmalloc(sizeof(struct close_me));
new->fd = fd;
new->next = close_me_head;
close_me_head = new;
}
static void mark_closed(int fd)
{
struct close_me *tmp;
if (close_me_head == NULL || close_me_head->fd != fd)
error_msg_and_die("corrupt close_me");
tmp = close_me_head;
close_me_head = close_me_head->next;
free(tmp);
}
static void close_all()
{
struct close_me *c;
for (c=close_me_head; c; c=c->next) {
close(c->fd);
}
close_me_head = NULL;
}
/* squirrel != NULL means we squirrel away copies of stdin, stdout,
* and stderr if they are redirected. */
static int setup_redirects(struct child_prog *prog, int squirrel[])
{
int openfd, mode;
struct redir_struct *redir;
for (redir=prog->redirects; redir; redir=redir->next) {
if (redir->dup == -1) {
mode=redir_table[redir->type].mode;
openfd = open(redir->word.gl_pathv[0], mode, 0666);
if (openfd < 0) {
/* this could get lost if stderr has been redirected, but
bash and ash both lose it as well (though zsh doesn't!) */
fprintf(stderr,"error opening %s: %s\n", redir->word.gl_pathv[0],
strerror(errno));
return 1;
}
} else {
openfd = redir->dup;
}
if (openfd != redir->fd) {
if (squirrel && redir->fd < 3) {
squirrel[redir->fd] = dup(redir->fd);
}
if (openfd == -3) {
close(openfd);
} else {
dup2(openfd, redir->fd);
close(openfd);
}
}
}
return 0;
}
static void restore_redirects(int squirrel[])
{
int i, fd;
for (i=0; i<3; i++) {
fd = squirrel[i];
if (fd != -1) {
/* No error checking. I sure wouldn't know what
* to do with an error if I found one! */
dup2(fd, i);
close(fd);
}
}
}
/* XXX this definitely needs some more thought, work, and
* cribbing from other shells */
static int pipe_wait(struct pipe *pi)
{
int rcode=0, i, pid, running, status;
running = pi->num_progs;
while (running) {
pid=waitpid(-1, &status, 0);
if (pid < 0) perror_msg_and_die("waitpid");
for (i=0; i < pi->num_progs; i++) {
if (pi->progs[i].pid == pid) {
if (i==pi->num_progs-1) rcode=WEXITSTATUS(status);
pi->progs[i].pid = 0;
running--;
break;
}
}
}
return rcode;
}
/* very simple version for testing */
static void pseudo_exec(struct child_prog *child)
{
int rcode;
struct built_in_command *x;
if (child->argv) {
/*
* Check if the command matches any of the builtins.
* Depending on context, this might be redundant. But it's
* easier to waste a few CPU cycles than it is to figure out
* if this is one of those cases.
*/
for (x = bltins; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0 ) {
debug_printf("builtin exec %s\n", child->argv[0]);
exit(x->function(child));
}
}
/* Check if the command matches any busybox internal commands
* ("applets") here.
* FIXME: This feature is not 100% safe, since
* BusyBox is not fully reentrant, so we have no guarantee the things
* from the .bss are still zeroed, or that things from .data are still
* at their defaults. We could exec ourself from /proc/self/exe, but I
* really dislike relying on /proc for things. We could exec ourself
* from global_argv[0], but if we are in a chroot, we may not be able
* to find ourself... */
#ifdef BB_FEATURE_SH_STANDALONE_SHELL
{
int argc_l;
char** argv_l=child->argv;
char *name = child->argv[0];
#ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
/* Following discussions from November 2000 on the busybox mailing
* list, the default configuration, (without
* get_last_path_component()) lets the user force use of an
* external command by specifying the full (with slashes) filename.
* If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then applets
* _aways_ override external commands, so if you want to run
* /bin/cat, it will use BusyBox cat even if /bin/cat exists on the
* filesystem and is _not_ busybox. Some systems may want this,
* most do not. */
name = get_last_path_component(name);
#endif
/* Count argc for use in a second... */
for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
optind = 1;
debug_printf("running applet %s\n", name);
run_applet_by_name(name, argc_l, child->argv);
}
#endif
debug_printf("exec of %s\n",child->argv[0]);
execvp(child->argv[0],child->argv);
perror("execvp");
exit(1);
} else if (child->group) {
debug_printf("runtime nesting to group\n");
interactive=0; /* crucial!!!! */
rcode = run_list_real(child->group);
/* OK to leak memory by not calling run_list_test,
* since this process is about to exit */
exit(rcode);
} else {
/* Can happen. See what bash does with ">foo" by itself. */
debug_printf("trying to pseudo_exec null command\n");
exit(EXIT_SUCCESS);
}
}
static void insert_bg_job(struct pipe *pi)
{
struct pipe *thejob;
/* Linear search for the ID of the job to use */
pi->jobid = 1;
for (thejob = job_list->head; thejob; thejob = thejob->next)
if (thejob->jobid >= pi->jobid)
pi->jobid = thejob->jobid + 1;
/* add thejob to the list of running jobs */
if (!job_list->head) {
thejob = job_list->head = xmalloc(sizeof(*thejob));
} else {
for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
thejob->next = xmalloc(sizeof(*thejob));
thejob = thejob->next;
}
/* physically copy the struct job */
memcpy(thejob, pi, sizeof(struct pipe));
thejob->next = NULL;
thejob->running_progs = thejob->num_progs;
thejob->stopped_progs = 0;
/* we don't wait for background thejobs to return -- append it
to the list of backgrounded thejobs and leave it alone */
printf("[%d] %d\n", pi->jobid, pi->pgrp);
last_bg_pid = pi->pgrp;
}
/* remove a backgrounded job from a jobset */
static void remove_bg_job(struct pipe *pi)
{
struct pipe *prev_pipe;
free_pipe(pi);
if (pi == job_list->head) {
job_list->head = pi->next;
} else {
prev_pipe = job_list->head;
while (prev_pipe->next != pi)
prev_pipe = prev_pipe->next;
prev_pipe->next = pi->next;
}
free(pi);
}
/* free up all memory from a pipe */
static void free_pipe(struct pipe *pi)
{
int i;
for (i = 0; i < pi->num_progs; i++) {
free(pi->progs[i].argv);
if (pi->progs[i].redirects)
free(pi->progs[i].redirects);
}
if (pi->progs)
free(pi->progs);
if (pi->text)
free(pi->text);
if (pi->cmdbuf)
free(pi->cmdbuf);
memset(pi, 0, sizeof(struct pipe));
}
/* Checks to see if any background processes have exited -- if they
have, figure out why and see if a job has completed */
static void checkjobs()
{
int status;
int prognum = 0;
struct pipe *pi;
pid_t childpid;
while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
for (pi = job_list->head; pi; pi = pi->next) {
prognum = 0;
while (prognum < pi->num_progs &&
pi->progs[prognum].pid != childpid) prognum++;
if (prognum < pi->num_progs)
break;
}
if (WIFEXITED(status) || WIFSIGNALED(status)) {
/* child exited */
pi->running_progs--;
pi->progs[prognum].pid = 0;
if (!pi->running_progs) {
printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
remove_bg_job(pi);
}
} else {
/* child stopped */
pi->stopped_progs++;
pi->progs[prognum].is_stopped = 1;
if (pi->stopped_progs == pi->num_progs) {
printf(JOB_STATUS_FORMAT, pi->jobid, "Stopped",
pi->text);
}
}
}
if (childpid == -1 && errno != ECHILD)
perror_msg("waitpid");
/* move the shell to the foreground */
if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
perror_msg("tcsetpgrp");
}
/* run_pipe_real() starts all the jobs, but doesn't wait for anything
* to finish. See pipe_wait().
*
* 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
* is a simple builtin command, however, the action is done by the
* time run_pipe_real returns, and the exit code is provided as the
* return value.
*
* The input of the pipe is always stdin, the output is always
* stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
* because it tries to avoid running the command substitution in
* subshell, when that is in fact necessary. The subshell process
* now has its stdout directed to the input of the appropriate pipe,
* so this routine is noticeably simpler.
*/
static int run_pipe_real(struct pipe *pi)
{
int i;
int ctty;
int nextin, nextout;
int pipefds[2]; /* pipefds[0] is for reading */
struct child_prog *child;
struct built_in_command *x;
ctty = -1;
nextin = 0;
pi->pgrp = 0;
/* Check if we are supposed to run in the foreground */
if (interactive && pi->followup!=PIPE_BG) {
if ((pi->pgrp = tcgetpgrp(ctty = 2)) < 0
&& (pi->pgrp = tcgetpgrp(ctty = 0)) < 0
&& (pi->pgrp = tcgetpgrp(ctty = 1)) < 0)
return errno = ENOTTY, -1;
if (pi->pgrp < 0 && pi->pgrp != getpgrp())
return errno = EPERM, -1;
}
/* Check if this is a simple builtin (not part of a pipe).
* Builtins within pipes have to fork anyway, and are handled in
* pseudo_exec. "echo foo | read bar" doesn't work on bash, either.
*/
if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
child = & (pi->progs[0]);
if (child->group && ! child->subshell) {
int squirrel[] = {-1, -1, -1};
int rcode;
debug_printf("non-subshell grouping\n");
setup_redirects(child, squirrel);
/* XXX could we merge code with following builtin case,
* by creating a pseudo builtin that calls run_list_real? */
rcode = run_list_real(child->group);
restore_redirects(squirrel);
return rcode;
}
for (x = bltins; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0 ) {
int squirrel[] = {-1, -1, -1};
int rcode;
if (x->function == builtin_exec && child->argv[1]==NULL) {
debug_printf("magic exec\n");
setup_redirects(child,NULL);
return EXIT_SUCCESS;
}
debug_printf("builtin inline %s\n", child->argv[0]);
/* XXX setup_redirects acts on file descriptors, not FILEs.
* This is perfect for work that comes after exec().
* Is it really safe for inline use? Experimentally,
* things seem to work with glibc. */
setup_redirects(child, squirrel);
rcode = x->function(child);
restore_redirects(squirrel);
return rcode;
}
}
}
for (i = 0; i < pi->num_progs; i++) {
child = & (pi->progs[i]);
/* pipes are inserted between pairs of commands */
if ((i + 1) < pi->num_progs) {
if (pipe(pipefds)<0) perror_msg_and_die("pipe");
nextout = pipefds[1];
} else {
nextout=1;
pipefds[0] = -1;
}
/* XXX test for failed fork()? */
if (!(child->pid = fork())) {
signal(SIGTTOU, SIG_DFL);
close_all();
if (nextin != 0) {
dup2(nextin, 0);
close(nextin);
}
if (nextout != 1) {
dup2(nextout, 1);
close(nextout);
}
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 (pi->followup!=PIPE_BG) {
/* Put our child in the process group whose leader is the
* first process in this pipe. */
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. */
if (setpgid(0, pi->pgrp) == 0) {
signal(SIGTTOU, SIG_IGN);
tcsetpgrp(ctty, pi->pgrp);
signal(SIGTTOU, 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->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);
if (nextin != 0)
close(nextin);
if (nextout != 1)
close(nextout);
/* If there isn't another process, nextin is garbage
but it doesn't matter */
nextin = pipefds[0];
}
return -1;
}
static int run_list_real(struct pipe *pi)
{
int rcode=0;
int if_code=0, next_if_code=0; /* need double-buffer to handle elif */
reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
for (;pi;pi=pi->next) {
rmode = pi->r_mode;
debug_printf("rmode=%d if_code=%d next_if_code=%d skip_more=%d\n", rmode, if_code, next_if_code, skip_more_in_this_rmode);
if (rmode == skip_more_in_this_rmode) continue;
skip_more_in_this_rmode = RES_XXXX;
if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
if (rmode == RES_THEN && if_code) continue;
if (rmode == RES_ELSE && !if_code) continue;
if (rmode == RES_ELIF && !if_code) continue;
if (pi->num_progs == 0) continue;
rcode = run_pipe_real(pi);
if (rcode!=-1) {
/* We only ran a builtin: rcode was set by the return value
* of run_pipe_real(), and we don't need to wait for anything. */
} else if (pi->followup==PIPE_BG) {
/* XXX check bash's behavior with nontrivial pipes */
/* XXX compute jobid */
/* XXX what does bash do with attempts to background builtins? */
insert_bg_job(pi);
rcode = EXIT_SUCCESS;
} else {
if (interactive) {
/* move the new process group into the foreground */
/* suppress messages when run from /linuxrc mag@sysgo.de */
//signal(SIGTTIN, SIG_IGN);
//signal(SIGTTOU, SIG_IGN);
if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
perror_msg("tcsetpgrp");
rcode = pipe_wait(pi);
if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
perror_msg("tcsetpgrp");
//signal(SIGTTIN, SIG_DFL);
//signal(SIGTTOU, SIG_DFL);
} else {
rcode = pipe_wait(pi);
}
}
last_return_code=rcode;
if ( rmode == RES_IF || rmode == RES_ELIF )
next_if_code=rcode; /* can be overwritten a number of times */
if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
(rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
skip_more_in_this_rmode=rmode;
/* return rcode; */ /* XXX broken if list is part of if/then/else */
}
checkjobs();
return rcode;
}
/* broken, of course, but OK for testing */
static char *indenter(int i)
{
static char blanks[]=" ";
return &blanks[sizeof(blanks)-i-1];
}
/* return code is the exit status of the pipe */
static int run_pipe_test(struct pipe *pi, int indent)
{
char **p;
struct child_prog *child;
struct redir_struct *r, *rnext;
int a, i, ret_code=0;
char *ind = indenter(indent);
final_printf("%s run pipe: (pid %d)\n",ind,getpid());
for (i=0; i<pi->num_progs; i++) {
child = &pi->progs[i];
final_printf("%s command %d:\n",ind,i);
if (child->argv) {
for (a=0,p=child->argv; *p; a++,p++) {
final_printf("%s argv[%d] = %s\n",ind,a,*p);
}
globfree(&child->glob_result);
child->argv=NULL;
} else if (child->group) {
final_printf("%s begin group (subshell:%d)\n",ind, child->subshell);
ret_code = run_list_test(child->group,indent+3);
final_printf("%s end group\n",ind);
} else {
final_printf("%s (nil)\n",ind);
}
for (r=child->redirects; r; r=rnext) {
final_printf("%s redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
if (r->dup == -1) {
final_printf(" %s\n", *r->word.gl_pathv);
globfree(&r->word);
} else {
final_printf("&%d\n", r->dup);
}
rnext=r->next;
free(r);
}
child->redirects=NULL;
}
free(pi->progs); /* children are an array, they get freed all at once */
pi->progs=NULL;
return ret_code;
}
static int run_list_test(struct pipe *head, int indent)
{
int rcode=0; /* if list has no members */
struct pipe *pi, *next;
char *ind = indenter(indent);
for (pi=head; pi; pi=next) {
if (pi->num_progs == 0) break;
final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
rcode = run_pipe_test(pi, indent);
final_printf("%s pipe followup code %d\n", ind, pi->followup);
next=pi->next;
pi->next=NULL;
free(pi);
}
return rcode;
}
/* Select which version we will use */
static int run_list(struct pipe *pi)
{
int rcode=0;
if (fake_mode==0) {
rcode = run_list_real(pi);
}
/* run_list_test has the side effect of clearing memory
* In the long run that function can be merged with run_list_real,
* but doing that now would hobble the debugging effort. */
run_list_test(pi,0);
return rcode;
}
/* The API for glob is arguably broken. This routine pushes a non-matching
* string into the output structure, removing non-backslashed backslashes.
* If someone can prove me wrong, by performing this function within the
* original glob(3) api, feel free to rewrite this routine into oblivion.
* Return code (0 vs. GLOB_NOSPACE) matches glob(3).
* XXX broken if the last character is '\\', check that before calling.
*/
static int globhack(const char *src, int flags, glob_t *pglob)
{
int cnt, pathc;
const char *s;
char *dest;
for (cnt=1, s=src; *s; s++) {
if (*s == '\\') s++;
cnt++;
}
dest = malloc(cnt);
if (!dest) return GLOB_NOSPACE;
if (!(flags & GLOB_APPEND)) {
pglob->gl_pathv=NULL;
pglob->gl_pathc=0;
pglob->gl_offs=0;
pglob->gl_offs=0;
}
pathc = ++pglob->gl_pathc;
pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
pglob->gl_pathv[pathc-1]=dest;
pglob->gl_pathv[pathc]=NULL;
for (s=src; *s; s++, dest++) {
if (*s == '\\') s++;
*dest = *s;
}
*dest='\0';
return 0;
}
/* XXX broken if the last character is '\\', check that before calling */
static int glob_needed(const char *s)
{
for (; *s; s++) {
if (*s == '\\') s++;
if (strchr("*[?",*s)) return 1;
}
return 0;
}
#if 0
static void globprint(glob_t *pglob)
{
int i;
debug_printf("glob_t at %p:\n", pglob);
debug_printf(" gl_pathc=%d gl_pathv=%p gl_offs=%d gl_flags=%d\n",
pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
for (i=0; i<pglob->gl_pathc; i++)
debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
pglob->gl_pathv[i], pglob->gl_pathv[i]);
}
#endif
static int xglob(o_string *dest, int flags, glob_t *pglob)
{
int gr;
/* short-circuit for null word */
/* we can code this better when the debug_printf's are gone */
if (dest->length == 0) {
if (dest->nonnull) {
/* bash man page calls this an "explicit" null */
gr = globhack(dest->data, flags, pglob);
debug_printf("globhack returned %d\n",gr);
} else {
return 0;
}
} else if (glob_needed(dest->data)) {
gr = glob(dest->data, flags, NULL, pglob);
debug_printf("glob returned %d\n",gr);
if (gr == GLOB_NOMATCH) {
/* quote removal, or more accurately, backslash removal */
gr = globhack(dest->data, flags, pglob);
debug_printf("globhack returned %d\n",gr);
}
} else {
gr = globhack(dest->data, flags, pglob);
debug_printf("globhack returned %d\n",gr);
}
if (gr == GLOB_NOSPACE) {
fprintf(stderr,"out of memory during glob\n");
exit(1);
}
if (gr != 0) { /* GLOB_ABORTED ? */
fprintf(stderr,"glob(3) error %d\n",gr);
}
/* globprint(glob_target); */
return gr;
}
/* the src parameter allows us to peek forward to a possible &n syntax
* for file descriptor duplication, e.g., "2>&1".
* Return code is 0 normally, 1 if a syntax error is detected in src.
* Resource errors (in xmalloc) cause the process to exit */
static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
struct in_str *input)
{
struct child_prog *child=ctx->child;
struct redir_struct *redir = child->redirects;
struct redir_struct *last_redir=NULL;
/* Create a new redir_struct and drop it onto the end of the linked list */
while(redir) {
last_redir=redir;
redir=redir->next;
}
redir = xmalloc(sizeof(struct redir_struct));
redir->next=NULL;
if (last_redir) {
last_redir->next=redir;
} else {
child->redirects=redir;
}
redir->type=style;
redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
/* Check for a '2>&1' type redirect */
redir->dup = redirect_dup_num(input);
if (redir->dup == -2) return 1; /* syntax error */
if (redir->dup != -1) {
/* Erik had a check here that the file descriptor in question
* is legit; I postpone that to "run time"
* A "-" representation of "close me" shows up as a -3 here */
debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
} else {
/* We do _not_ try to open the file that src points to,
* since we need to return and let src be expanded first.
* Set ctx->pending_redirect, so we know what to do at the
* end of the next parsed word.
*/
ctx->pending_redirect = redir;
}
return 0;
}
struct pipe *new_pipe(void) {
struct pipe *pi;
pi = xmalloc(sizeof(struct pipe));
pi->num_progs = 0;
pi->progs = NULL;
pi->next = NULL;
pi->followup = 0; /* invalid */
return pi;
}
static void initialize_context(struct p_context *ctx)
{
ctx->pipe=NULL;
ctx->pending_redirect=NULL;
ctx->child=NULL;
ctx->list_head=new_pipe();
ctx->pipe=ctx->list_head;
ctx->w=RES_NONE;
ctx->stack=NULL;
done_command(ctx); /* creates the memory for working child */
}
/* normal return is 0
* if a reserved word is found, and processed, return 1
* should handle if, then, elif, else, fi, for, while, until, do, done.
* case, function, and select are obnoxious, save those for later.
*/
int reserved_word(o_string *dest, struct p_context *ctx)
{
struct reserved_combo {
char *literal;
int code;
long flag;
};
/* Mostly a list of accepted follow-up reserved words.
* FLAG_END means we are done with the sequence, and are ready
* to turn the compound list into a command.
* FLAG_START means the word must start a new compound list.
*/
static struct reserved_combo reserved_list[] = {
{ "if", RES_IF, FLAG_THEN | FLAG_START },
{ "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
{ "elif", RES_ELIF, FLAG_THEN },
{ "else", RES_ELSE, FLAG_FI },
{ "fi", RES_FI, FLAG_END },
{ "for", RES_FOR, FLAG_DO | FLAG_START },
{ "while", RES_WHILE, FLAG_DO | FLAG_START },
{ "until", RES_UNTIL, FLAG_DO | FLAG_START },
{ "do", RES_DO, FLAG_DONE },
{ "done", RES_DONE, FLAG_END }
};
struct reserved_combo *r;
for (r=reserved_list;
#define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
r<reserved_list+NRES; r++) {
if (strcmp(dest->data, r->literal) == 0) {
debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
if (r->flag & FLAG_START) {
struct p_context *new = xmalloc(sizeof(struct p_context));
debug_printf("push stack\n");
*new = *ctx; /* physical copy */
initialize_context(ctx);
ctx->stack=new;
} else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
syntax();
ctx->w = RES_SNTX;
b_reset (dest);
return 1;
}
ctx->w=r->code;
ctx->old_flag = r->flag;
if (ctx->old_flag & FLAG_END) {
struct p_context *old;
debug_printf("pop stack\n");
old = ctx->stack;
old->child->group = ctx->list_head;
*ctx = *old; /* physical copy */
free(old);
}
b_reset (dest);
return 1;
}
}
return 0;
}
/* normal return is 0.
* Syntax or xglob errors return 1. */
static int done_word(o_string *dest, struct p_context *ctx)
{
struct child_prog *child=ctx->child;
glob_t *glob_target;
int gr, flags = 0;
debug_printf("done_word: %s %p\n", dest->data, child);
if (dest->length == 0 && !dest->nonnull) {
debug_printf(" true null, ignored\n");
return 0;
}
if (ctx->pending_redirect) {
glob_target = &ctx->pending_redirect->word;
} else {
if (child->group) {
syntax();
return 1; /* syntax error, groups and arglists don't mix */
}
if (!child->argv) {
debug_printf("checking %s for reserved-ness\n",dest->data);
if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
}
glob_target = &child->glob_result;
if (child->argv) flags |= GLOB_APPEND;
}
gr = xglob(dest, flags, glob_target);
if (gr != 0) return 1;
b_reset(dest);
if (ctx->pending_redirect) {
ctx->pending_redirect=NULL;
if (glob_target->gl_pathc != 1) {
fprintf(stderr, "ambiguous redirect\n");
return 1;
}
} else {
child->argv = glob_target->gl_pathv;
}
return 0;
}
/* The only possible error here is out of memory, in which case
* xmalloc exits. */
static int done_command(struct p_context *ctx)
{
/* The child is really already in the pipe structure, so
* advance the pipe counter and make a new, null child.
* Only real trickiness here is that the uncommitted
* child structure, to which ctx->child points, is not
* counted in pi->num_progs. */
struct pipe *pi=ctx->pipe;
struct child_prog *prog=ctx->child;
if (prog && prog->group == NULL
&& prog->argv == NULL
&& prog->redirects == NULL) {
debug_printf("done_command: skipping null command\n");
return 0;
} else if (prog) {
pi->num_progs++;
debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
} else {
debug_printf("done_command: initializing\n");
}
pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
prog = pi->progs + pi->num_progs;
prog->redirects = NULL;
prog->argv = NULL;
prog->is_stopped = 0;
prog->group = NULL;
prog->glob_result.gl_pathv = NULL;
prog->family = pi;
ctx->child=prog;
/* but ctx->pipe and ctx->list_head remain unchanged */
return 0;
}
static int done_pipe(struct p_context *ctx, pipe_style type)
{
struct pipe *new_p;
done_command(ctx); /* implicit closure of previous command */
debug_printf("done_pipe, type %d\n", type);
ctx->pipe->followup = type;
ctx->pipe->r_mode = ctx->w;
new_p=new_pipe();
ctx->pipe->next = new_p;
ctx->pipe = new_p;
ctx->child = NULL;
done_command(ctx); /* set up new pipe to accept commands */
return 0;
}
/* peek ahead in the in_str to find out if we have a "&n" construct,
* as in "2>&1", that represents duplicating a file descriptor.
* returns either -2 (syntax error), -1 (no &), or the number found.
*/
static int redirect_dup_num(struct in_str *input)
{
int ch, d=0, ok=0;
ch = b_peek(input);
if (ch != '&') return -1;
b_getch(input); /* get the & */
ch=b_peek(input);
if (ch == '-') {
b_getch(input);
return -3; /* "-" represents "close me" */
}
while (isdigit(ch)) {
d = d*10+(ch-'0');
ok=1;
b_getch(input);
ch = b_peek(input);
}
if (ok) return d;
fprintf(stderr, "ambiguous redirect\n");
return -2;
}
/* If a redirect is immediately preceded by a number, that number is
* supposed to tell which file descriptor to redirect. This routine
* looks for such preceding numbers. In an ideal world this routine
* needs to handle all the following classes of redirects...
* echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
* echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
* echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
* echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
* A -1 output from this program means no valid number was found, so the
* caller should use the appropriate default for this redirection.
*/
static int redirect_opt_num(o_string *o)
{
int num;
if (o->length==0) return -1;
for(num=0; num<o->length; num++) {
if (!isdigit(*(o->data+num))) {
return -1;
}
}
/* reuse num (and save an int) */
num=atoi(o->data);
b_reset(o);
return num;
}
FILE *generate_stream_from_list(struct pipe *head)
{
FILE *pf;
#if 1
int pid, channel[2];
if (pipe(channel)<0) perror_msg_and_die("pipe");
pid=fork();
if (pid<0) {
perror_msg_and_die("fork");
} else if (pid==0) {
close(channel[0]);
if (channel[1] != 1) {
dup2(channel[1],1);
close(channel[1]);
}
#if 0
#define SURROGATE "surrogate response"
write(1,SURROGATE,sizeof(SURROGATE));
exit(run_list(head));
#else
exit(run_list_real(head)); /* leaks memory */
#endif
}
debug_printf("forked child %d\n",pid);
close(channel[1]);
pf = fdopen(channel[0],"r");
debug_printf("pipe on FILE *%p\n",pf);
#else
run_list_test(head,0);
pf=popen("echo surrogate response","r");
debug_printf("started fake pipe on FILE *%p\n",pf);
#endif
return pf;
}
/* this version hacked for testing purposes */
/* return code is exit status of the process that is run. */
static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
{
int retcode;
o_string result=NULL_O_STRING;
struct p_context inner;
FILE *p;
struct in_str pipe_str;
initialize_context(&inner);
/* recursion to generate command */
retcode = parse_stream(&result, &inner, input, subst_end);
if (retcode != 0) return retcode; /* syntax error or EOF */
done_word(&result, &inner);
done_pipe(&inner, PIPE_SEQ);
b_free(&result);
p=generate_stream_from_list(inner.list_head);
if (p==NULL) return 1;
mark_open(fileno(p));
setup_file_in_str(&pipe_str, p);
/* now send results of command back into original context */
retcode = parse_stream(dest, ctx, &pipe_str, '\0');
/* XXX In case of a syntax error, should we try to kill the child?
* That would be tough to do right, so just read until EOF. */
if (retcode == 1) {
while (b_getch(&pipe_str)!=EOF) { /* discard */ };
}
debug_printf("done reading from pipe, pclose()ing\n");
/* This is the step that wait()s for the child. Should be pretty
* safe, since we just read an EOF from its stdout. We could try
* to better, by using wait(), and keeping track of background jobs
* at the same time. That would be a lot of work, and contrary
* to the KISS philosophy of this program. */
mark_closed(fileno(p));
retcode=pclose(p);
debug_printf("pclosed, retcode=%d\n",retcode);
/* XXX this process fails to trim a single trailing newline */
return retcode;
}
static int parse_group(o_string *dest, struct p_context *ctx,
struct in_str *input, int ch)
{
int rcode, endch=0;
struct p_context sub;
struct child_prog *child = ctx->child;
if (child->argv) {
syntax();
return 1; /* syntax error, groups and arglists don't mix */
}
initialize_context(&sub);
switch(ch) {
case '(': endch=')'; child->subshell=1; break;
case '{': endch='}'; break;
default: syntax(); /* really logic error */
}
rcode=parse_stream(dest,&sub,input,endch);
done_word(dest,&sub); /* finish off the final word in the subcontext */
done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */
child->group = sub.list_head;
return rcode;
/* child remains "open", available for possible redirects */
}
/* basically useful version until someone wants to get fancier,
* see the bash man page under "Parameter Expansion" */
static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src)
{
const char *p=NULL;
if (src->data) p = getenv(src->data);
if (p) parse_string(dest, ctx, p); /* recursion */
b_free(src);
}
/* return code: 0 for OK, 1 for syntax error */
static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
{
int i, advance=0;
o_string alt=NULL_O_STRING;
char sep[]=" ";
int ch = input->peek(input); /* first character after the $ */
debug_printf("handle_dollar: ch=%c\n",ch);
if (isalpha(ch)) {
while(ch=b_peek(input),isalnum(ch) || ch=='_') {
b_getch(input);
b_addchr(&alt,ch);
}
lookup_param(dest, ctx, &alt);
} else if (isdigit(ch)) {
i = ch-'0'; /* XXX is $0 special? */
if (i<global_argc) {
parse_string(dest, ctx, global_argv[i]); /* recursion */
}
advance = 1;
} else switch (ch) {
case '$':
b_adduint(dest,getpid());
advance = 1;
break;
case '!':
if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
advance = 1;
break;
case '?':
b_adduint(dest,last_return_code);
advance = 1;
break;
case '#':
b_adduint(dest,global_argc ? global_argc-1 : 0);
advance = 1;
break;
case '{':
b_getch(input);
/* XXX maybe someone will try to escape the '}' */
while(ch=b_getch(input),ch!=EOF && ch!='}') {
b_addchr(&alt,ch);
}
if (ch != '}') {
syntax();
return 1;
}
lookup_param(dest, ctx, &alt);
break;
case '(':
b_getch(input);
process_command_subs(dest, ctx, input, ')');
break;
case '*':
sep[0]=ifs[0];
for (i=1; i<global_argc; i++) {
parse_string(dest, ctx, global_argv[i]);
if (i+1 < global_argc) parse_string(dest, ctx, sep);
}
break;
case '@':
case '-':
case '_':
/* still unhandled, but should be eventually */
fprintf(stderr,"unhandled syntax: $%c\n",ch);
return 1;
break;
default:
b_addqchr(dest,'$',dest->quote);
}
/* Eat the character if the flag was set. If the compiler
* is smart enough, we could substitute "b_getch(input);"
* for all the "advance = 1;" above, and also end up with
* a nice size-optimized program. Hah! That'll be the day.
*/
if (advance) b_getch(input);
return 0;
}
int parse_string(o_string *dest, struct p_context *ctx, const char *src)
{
struct in_str foo;
setup_string_in_str(&foo, src);
return parse_stream(dest, ctx, &foo, '\0');
}
/* return code is 0 for normal exit, 1 for syntax error */
int parse_stream(o_string *dest, struct p_context *ctx,
struct in_str *input, int end_trigger)
{
unsigned int ch, m;
int redir_fd;
redir_type redir_style;
int next;
/* Only double-quote state is handled in the state variable dest->quote.
* A single-quote triggers a bypass of the main loop until its mate is
* found. When recursing, quote state is passed in via dest->quote. */
debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
while ((ch=b_getch(input))!=EOF) {
m = map[ch];
next = (ch == '\n') ? 0 : b_peek(input);
debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
ch,ch,m,dest->quote);
if (m==0 || ((m==1 || m==2) && dest->quote)) {
b_addqchr(dest, ch, dest->quote);
} else {
if (m==2) { /* unquoted IFS */
done_word(dest, ctx);
/* If we aren't performing a substitution, treat a newline as a
* command separator. */
if (end_trigger != '\0' && ch=='\n')
done_pipe(ctx,PIPE_SEQ);
}
if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
debug_printf("leaving parse_stream\n");
return 0;
}
#if 0
if (ch=='\n') {
/* Yahoo! Time to run with it! */
done_pipe(ctx,PIPE_SEQ);
run_list(ctx->list_head);
initialize_context(ctx);
}
#endif
if (m!=2) switch (ch) {
case '#':
if (dest->length == 0 && !dest->quote) {
while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
} else {
b_addqchr(dest, ch, dest->quote);
}
break;
case '\\':
if (next == EOF) {
syntax();
return 1;
}
b_addqchr(dest, '\\', dest->quote);
b_addqchr(dest, b_getch(input), dest->quote);
break;
case '$':
if (handle_dollar(dest, ctx, input)!=0) return 1;
break;
case '\'':
dest->nonnull = 1;
while(ch=b_getch(input),ch!=EOF && ch!='\'') {
b_addchr(dest,ch);
}
if (ch==EOF) {
syntax();
return 1;
}
break;
case '"':
dest->nonnull = 1;
dest->quote = !dest->quote;
break;
case '`':
process_command_subs(dest, ctx, input, '`');
break;
case '>':
redir_fd = redirect_opt_num(dest);
done_word(dest, ctx);
redir_style=REDIRECT_OVERWRITE;
if (next == '>') {
redir_style=REDIRECT_APPEND;
b_getch(input);
} else if (next == '(') {
syntax(); /* until we support >(list) Process Substitution */
return 1;
}
setup_redirect(ctx, redir_fd, redir_style, input);
break;
case '<':
redir_fd = redirect_opt_num(dest);
done_word(dest, ctx);
redir_style=REDIRECT_INPUT;
if (next == '<') {
redir_style=REDIRECT_HEREIS;
b_getch(input);
} else if (next == '>') {
redir_style=REDIRECT_IO;
b_getch(input);
} else if (next == '(') {
syntax(); /* until we support <(list) Process Substitution */
return 1;
}
setup_redirect(ctx, redir_fd, redir_style, input);
break;
case ';':
done_word(dest, ctx);
done_pipe(ctx,PIPE_SEQ);
break;
case '&':
done_word(dest, ctx);
if (next=='&') {
b_getch(input);
done_pipe(ctx,PIPE_AND);
} else {
done_pipe(ctx,PIPE_BG);
}
break;
case '|':
done_word(dest, ctx);
if (next=='|') {
b_getch(input);
done_pipe(ctx,PIPE_OR);
} else {
/* we could pick up a file descriptor choice here
* with redirect_opt_num(), but bash doesn't do it.
* "echo foo 2| cat" yields "foo 2". */
done_command(ctx);
}
break;
case '(':
case '{':
if (parse_group(dest, ctx, input, ch)!=0) return 1;
break;
case ')':
case '}':
syntax(); /* Proper use of this character caught by end_trigger */
return 1;
break;
default:
syntax(); /* this is really an internal logic error */
return 1;
}
}
}
/* complain if quote? No, maybe we just finished a command substitution
* that was quoted. Example:
* $ echo "`cat foo` plus more"
* and we just got the EOF generated by the subshell that ran "cat foo"
* The only real complaint is if we got an EOF when end_trigger != '\0',
* that is, we were really supposed to get end_trigger, and never got
* one before the EOF. Can't use the standard "syntax error" return code,
* so that parse_stream_outer can distinguish the EOF and exit smoothly. */
if (end_trigger != '\0') return -1;
return 0;
}
void mapset(const unsigned char *set, int code)
{
const unsigned char *s;
for (s=set; *s; s++) map[*s] = code;
}
void update_ifs_map(void)
{
/* char *ifs and char map[256] are both globals. */
ifs = getenv("IFS");
if (ifs == NULL) ifs=" \t\n";
/* Precompute a list of 'flow through' behavior so it can be treated
* quickly up front. Computation is necessary because of IFS.
* Special case handling of IFS == " \t\n" is not implemented.
* The map[] array only really needs two bits each, and on most machines
* that would be faster because of the reduced L1 cache footprint.
*/
memset(map,0,256); /* most characters flow through always */
mapset("\\$'\"`", 3); /* never flow through */
mapset("<>;&|(){}#", 1); /* flow through if quoted */
mapset(ifs, 2); /* also flow through if quoted */
}
/* most recursion does not come through here, the exeception is
* from builtin_source() */
int parse_stream_outer(struct in_str *inp)
{
struct p_context ctx;
o_string temp=NULL_O_STRING;
int rcode;
do {
initialize_context(&ctx);
update_ifs_map();
inp->promptmode=1;
rcode = parse_stream(&temp, &ctx, inp, '\n');
done_word(&temp, &ctx);
done_pipe(&ctx,PIPE_SEQ);
run_list(ctx.list_head);
} while (rcode != -1); /* loop on syntax errors, return on EOF */
return 0;
}
static int parse_string_outer(const char *s)
{
struct in_str input;
setup_string_in_str(&input, s);
return parse_stream_outer(&input);
}
static int parse_file_outer(FILE *f)
{
int rcode;
struct in_str input;
setup_file_in_str(&input, f);
rcode = parse_stream_outer(&input);
return rcode;
}
int shell_main(int argc, char **argv)
{
int opt;
FILE *input;
struct jobset joblist_end = { NULL, NULL };
job_list = &joblist_end;
last_return_code=EXIT_SUCCESS;
/* XXX what should these be while sourcing /etc/profile? */
global_argc = argc;
global_argv = argv;
/* don't pay any attention to this signal; it just confuses
things and isn't really meant for shells anyway */
signal(SIGTTOU, SIG_IGN);
if (argv[0] && argv[0][0] == '-') {
debug_printf("\nsourcing /etc/profile\n");
input = xfopen("/etc/profile", "r");
mark_open(fileno(input));
parse_file_outer(input);
mark_closed(fileno(input));
fclose(input);
}
input=stdin;
/* initialize the cwd -- this is never freed...*/
cwd = xgetcwd(0);
#ifdef BB_FEATURE_COMMAND_EDITING
cmdedit_set_initial_prompt();
#else
PS1 = NULL;
#endif
while ((opt = getopt(argc, argv, "c:xif")) > 0) {
switch (opt) {
case 'c':
{
global_argv = argv+optind;
global_argc = argc-optind;
opt = parse_string_outer(optarg);
goto final_return;
}
break;
case 'i':
interactive++;
break;
case 'f':
fake_mode++;
break;
default:
fprintf(stderr, "Usage: sh [FILE]...\n"
" or: sh -c command [args]...\n\n");
exit(EXIT_FAILURE);
}
}
/* A shell is interactive if the `-i' flag was given, or if all of
* the following conditions are met:
* no -c command
* no arguments remaining or the -s flag given
* standard input is a terminal
* standard output is a terminal
* Refer to Posix.2, the description of the `sh' utility. */
if (argv[optind]==NULL && input==stdin &&
isatty(fileno(stdin)) && isatty(fileno(stdout))) {
interactive++;
}
debug_printf("\ninteractive=%d\n", interactive);
if (interactive) {
/* Looks like they want an interactive shell */
fprintf(stdout, "\nhush -- the humble shell v0.01 (testing)\n\n");
opt=parse_file_outer(stdin);
goto final_return;
}
debug_printf("\nrunning script '%s'\n", argv[optind]);
global_argv = argv+optind;
global_argc = argc-optind;
input = xfopen(argv[optind], "r");
opt = parse_file_outer(input);
#ifdef BB_FEATURE_CLEAN_UP
fclose(input.file);
#endif
final_return:
return(opt?opt:last_return_code);
}
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