ash.c

手机嵌入式Linux下可用的busybox源码

/* vi: set sw=4 ts=4: */
/*
 * ash shell port for busybox
 *
 * Copyright (c) 1989, 1991, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * 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
 *
 * This version of ash is adapted from the source in Debian's ash 0.3.8-5
 * package.
 *
 * Modified by Erik Andersen <[e-mail]> and
 * Vladimir Oleynik <[e-mail]> to be used in busybox
 *
 *
 * Original copyright notice is retained at the end of this file.
 */


/* This enables alias support in ash.  If you want to support things
 * like "alias ls='ls -l'" with ash, enable this.  This is only useful
 * when ash is used as an intractive shell.   This adds about 1.5k */
#define CONFIG_ASH_ALIAS

/* If you need ash to act as a full Posix shell, with full math
 * support, enable this.   This adds a bit over 2k an x86 system. */
#define CONFIG_ASH_MATH_SUPPORT

/* Getopts is used by shell procedures to parse positional parameters.
 * You probably want to leave this disabled, and use the busybox getopt
 * applet if you want to do this sort of thing.  There are some scripts
 * out there that use it, so if you need it, enable it.  Most people will
 * leave this disabled.  This adds 1k on an x86 system. */
#undef CONFIG_ASH_GETOPTS

/* This allows you to override shell builtins and use whatever is on
 * the filesystem.  This is most useful when ash is acting as a
 * standalone shell.   Adds about 272 bytes. */
#undef CONFIG_ASH_CMDCMD

/* Check for mail */
#undef CONFIG_ASH_MAIL

/* Optimize size vs speed as size */
#define CONFIG_ASH_OPTIMIZE_FOR_SIZE

/* Enable this to compile in extra debugging noise.  When debugging is
 * on, debugging info will be written to $HOME/trace and a quit signal
 * will generate a core dump. */
#undef DEBUG

/* These are here to work with glibc -- Don't change these... */
#undef FNMATCH_BROKEN
#undef GLOB_BROKEN
#define IFS_BROKEN

#include <assert.h>
#include <stddef.h>
#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <paths.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/cdefs.h>
#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/resource.h>
#include <sys/time.h>
#include <sys/times.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "busybox.h"
#include "pwd_grp/pwd.h"


#if !defined(FNMATCH_BROKEN)
#include <fnmatch.h>
#endif
#if !defined(GLOB_BROKEN)
#include <glob.h>
#endif

#ifdef BB_FEATURE_ASH_JOB_CONTROL
#include <termios.h>
#endif

#include "cmdedit.h"


#if defined(__uClinux__)
#error "Do not even bother, ash will not run on uClinux"
#endif

/*
 * This file was generated by the mksyntax program.
 */

/* Syntax classes */
#define CWORD 0			/* character is nothing special */
#define CNL 1			/* newline character */
#define CBACK 2			/* a backslash character */
#define CSQUOTE 3		/* single quote */
#define CDQUOTE 4		/* double quote */
#define CENDQUOTE 5		/* a terminating quote */
#define CBQUOTE 6		/* backwards single quote */
#define CVAR 7			/* a dollar sign */
#define CENDVAR 8		/* a '}' character */
#define CLP 9			/* a left paren in arithmetic */
#define CRP 10			/* a right paren in arithmetic */
#define CENDFILE 11		/* end of file */
#define CCTL 12			/* like CWORD, except it must be escaped */
#define CSPCL 13		/* these terminate a word */
#define CIGN 14			/* character should be ignored */

#define SYNBASE 130
#define PEOF -130

#define PEOA -129

#define TEOF 0
#define TNL 1
#define TREDIR 2
#define TWORD 3
#define TASSIGN 4
#define TSEMI 5
#define TBACKGND 6
#define TAND 7
#define TOR 8
#define TPIPE 9
#define TLP 10
#define TRP 11
#define TENDCASE 12
#define TENDBQUOTE 13
#define TNOT 14
#define TCASE 15
#define TDO 16
#define TDONE 17
#define TELIF 18
#define TELSE 19
#define TESAC 20
#define TFI 21
#define TFOR 22
#define TIF 23
#define TIN 24
#define TTHEN 25
#define TUNTIL 26
#define TWHILE 27
#define TBEGIN 28
#define TEND 29



/* control characters in argument strings */
#define CTLESC '\201'
#define CTLVAR '\202'
#define CTLENDVAR '\203'
#define CTLBACKQ '\204'
#define CTLQUOTE 01		/* ored with CTLBACKQ code if in quotes */
/*      CTLBACKQ | CTLQUOTE == '\205' */
#define CTLARI  '\206'
#define CTLENDARI '\207'
#define CTLQUOTEMARK '\210'


#define is_digit(c)     ((c)>='0' && (c)<='9')
#define is_name(c)      (((c) < CTLESC || (c) > CTLENDARI) && ((c) == '_' || isalpha((unsigned char) (c))))
#define is_in_name(c)   (((c) < CTLESC || (c) > CTLENDARI) && ((c) == '_' || isalnum((unsigned char) (c))))

/*
 * is_special(c) evaluates to 1 for c in "!#$*-0123456789?@"; 0 otherwise
 * (assuming ascii char codes, as the original implementation did)
 */
#define is_special(c) \
    ( (((unsigned int)c) - 33 < 32) \
			 && ((0xc1ff920dUL >> (((unsigned int)c) - 33)) & 1))

#define digit_val(c)    ((c) - '0')


#define S_DFL 1			/* default signal handling (SIG_DFL) */
#define S_CATCH 2		/* signal is caught */
#define S_IGN 3			/* signal is ignored (SIG_IGN) */
#define S_HARD_IGN 4	/* signal is ignored permenantly */
#define S_RESET 5		/* temporary - to reset a hard ignored sig */


/* variable substitution byte (follows CTLVAR) */
#define VSTYPE  0x0f	/* type of variable substitution */
#define VSNUL   0x10	/* colon--treat the empty string as unset */
#define VSQUOTE 0x80	/* inside double quotes--suppress splitting */

/* values of VSTYPE field */
#define VSNORMAL        0x1	/* normal variable:  $var or ${var} */
#define VSMINUS         0x2	/* ${var-text} */
#define VSPLUS          0x3	/* ${var+text} */
#define VSQUESTION      0x4	/* ${var?message} */
#define VSASSIGN        0x5	/* ${var=text} */
#define VSTRIMLEFT      0x6	/* ${var#pattern} */
#define VSTRIMLEFTMAX   0x7	/* ${var##pattern} */
#define VSTRIMRIGHT     0x8	/* ${var%pattern} */
#define VSTRIMRIGHTMAX  0x9	/* ${var%%pattern} */
#define VSLENGTH        0xa	/* ${#var} */

/* flags passed to redirect */
#define REDIR_PUSH 01	/* save previous values of file descriptors */
#define REDIR_BACKQ 02	/* save the command output to pipe */

/*
 * BSD setjmp saves the signal mask, which violates ANSI C and takes time,
 * so we use _setjmp instead.
 */

#if defined(BSD)
#define setjmp(jmploc)  _setjmp(jmploc)
#define longjmp(jmploc, val)    _longjmp(jmploc, val)
#endif

/*
 * Most machines require the value returned from malloc to be aligned
 * in some way.  The following macro will get this right on many machines.
 */

#ifndef ALIGN
union align {
	int i;
	char *cp;
};

#define ALIGN(nbytes)   (((nbytes) + sizeof(union align) - 1) & ~(sizeof(union align) - 1))
#endif

#ifdef BB_LOCALE_SUPPORT
#include <locale.h>
static void change_lc_all(const char *value);
static void change_lc_ctype(const char *value);
#endif

/*
 * These macros allow the user to suspend the handling of interrupt signals
 * over a period of time.  This is similar to SIGHOLD to or sigblock, but
 * much more efficient and portable.  (But hacking the kernel is so much
 * more fun than worrying about efficiency and portability. :-))
 */

static void onint(void);
static volatile int suppressint;
static volatile int intpending;

#define INTOFF suppressint++
#ifndef CONFIG_ASH_OPTIMIZE_FOR_SIZE
#define INTON { if (--suppressint == 0 && intpending) onint(); }
#define FORCEINTON {suppressint = 0; if (intpending) onint();}
#else
static void __inton(void);
static void forceinton(void);

#define INTON __inton()
#define FORCEINTON forceinton()
#endif

#define CLEAR_PENDING_INT intpending = 0
#define int_pending() intpending


typedef void *pointer;

#ifndef NULL
#define NULL (void *)0
#endif

static pointer stalloc(int);
static void stunalloc(pointer);
static void ungrabstackstr(char *, char *);
static char *growstackstr(void);
static char *makestrspace(size_t newlen);

/*
 * Parse trees for commands are allocated in lifo order, so we use a stack
 * to make this more efficient, and also to avoid all sorts of exception
 * handling code to handle interrupts in the middle of a parse.
 *
 * The size 504 was chosen because the Ultrix malloc handles that size
 * well.
 */

#define MINSIZE 504		/* minimum size of a block */


struct stack_block {
	struct stack_block *prev;
	char space[MINSIZE];
};

static struct stack_block stackbase;
static struct stack_block *stackp = &stackbase;
static struct stackmark *markp;
static char *stacknxt = stackbase.space;
static int stacknleft = MINSIZE;


#define equal(s1, s2)   (strcmp(s1, s2) == 0)

#define stackblock() stacknxt
#define stackblocksize() stacknleft
#define STARTSTACKSTR(p)        p = stackblock(), sstrnleft = stackblocksize()

#define STPUTC(c, p)    (--sstrnleft >= 0? (*p++ = (c)) : (p = growstackstr(), *p++ = (c)))
#define CHECKSTRSPACE(n, p)     { if (sstrnleft < n) p = makestrspace(n); }
#define STACKSTRNUL(p)  (sstrnleft == 0? (p = growstackstr(), *p = '\0') : (*p = '\0'))


#define USTPUTC(c, p)   (--sstrnleft, *p++ = (c))
#define STUNPUTC(p)     (++sstrnleft, --p)
#define STTOPC(p)       p[-1]
#define STADJUST(amount, p)     (p += (amount), sstrnleft -= (amount))
#define grabstackstr(p) stalloc(stackblocksize() - sstrnleft)


#ifdef DEBUG
#define TRACE(param)    trace param
typedef union node unode;
static void trace(const char *, ...);
static void trargs(char **);
static void showtree(unode *);
static void trputc(int);
static void trputs(const char *);
static void opentrace(void);
#else
#define TRACE(param)
#endif

#define NSEMI 0
#define NCMD 1
#define NPIPE 2
#define NREDIR 3
#define NBACKGND 4
#define NSUBSHELL 5
#define NAND 6
#define NOR 7
#define NIF 8
#define NWHILE 9
#define NUNTIL 10
#define NFOR 11
#define NCASE 12
#define NCLIST 13
#define NDEFUN 14
#define NARG 15
#define NTO 16
#define NFROM 17
#define NFROMTO 18
#define NAPPEND 19
#define NTOOV 20
#define NTOFD 21
#define NFROMFD 22
#define NHERE 23
#define NXHERE 24
#define NNOT 25

/*
 * expandarg() flags
 */
#define EXP_FULL        0x1	/* perform word splitting & file globbing */
#define EXP_TILDE       0x2	/* do normal tilde expansion */
#define EXP_VARTILDE    0x4	/* expand tildes in an assignment */
#define EXP_REDIR       0x8	/* file glob for a redirection (1 match only) */
#define EXP_CASE        0x10	/* keeps quotes around for CASE pattern */
#define EXP_RECORD      0x20	/* need to record arguments for ifs breakup */


#define NOPTS   16

static char optet_vals[NOPTS];

static const char *const optlist[NOPTS] = {
	"e" "errexit",
	"f" "noglob",
	"I" "ignoreeof",
	"i" "interactive",
	"m" "monitor",
	"n" "noexec",
	"s" "stdin",
	"x" "xtrace",
	"v" "verbose",
	"V" "vi",
	"E" "emacs",
	"C" "noclobber",
	"a" "allexport",
	"b" "notify",
	"u" "nounset",
	"q" "quietprofile"
};

#define optent_name(optent) (optent+1)
#define optent_letter(optent) optent[0]
#define optent_val(optent) optet_vals[optent]

#define eflag optent_val(0)
#define fflag optent_val(1)
#define Iflag optent_val(2)
#define iflag optent_val(3)
#define mflag optent_val(4)
#define nflag optent_val(5)
#define sflag optent_val(6)
#define xflag optent_val(7)
#define vflag optent_val(8)
#define Vflag optent_val(9)
#define Eflag optent_val(10)
#define Cflag optent_val(11)
#define aflag optent_val(12)
#define bflag optent_val(13)
#define uflag optent_val(14)
#define qflag optent_val(15)


/* Mode argument to forkshell.  Don't change FORK_FG or FORK_BG. */
#define FORK_FG 0
#define FORK_BG 1
#define FORK_NOJOB 2


struct nbinary {
	int type;
	union node *ch1;
	union node *ch2;
};


struct ncmd {
	int type;
	int backgnd;
	union node *assign;
	union node *args;
	union node *redirect;
};


struct npipe {
	int type;
	int backgnd;
	struct nodelist *cmdlist;
};


struct nredir {
	int type;
	union node *n;
	union node *redirect;
};


struct nif {
	int type;
	union node *test;
	union node *ifpart;
	union node *elsepart;
};


struct nfor {
	int type;
	union node *args;
	union node *body;
	char *var;
};


struct ncase {
	int type;
	union node *expr;
	union node *cases;
};


struct nclist {
	int type;
	union node *next;
	union node *pattern;