ash.c

为samsung2410 ARM移植的busybox工具包

	return (i);
}

static struct alias **
hashalias(p)
	const char *p;
	{
	unsigned int hashval;

	hashval = *p << 4;
	while (*p)
		hashval+= *p++;
	return &atab[hashval % ATABSIZE];
}

static struct alias *
freealias(struct alias *ap) {
	struct alias *next;

	if (ap->flag & ALIASINUSE) {
		ap->flag |= ALIASDEAD;
		return ap;
	}

	next = ap->next;
	ckfree(ap->name);
	ckfree(ap->val);
	ckfree(ap);
	return next;
}


static struct alias **
__lookupalias(const char *name) {
	struct alias **app = hashalias(name);

	for (; *app; app = &(*app)->next) {
		if (equal(name, (*app)->name)) {
			break;
		}
	}

	return app;
}
#endif

#ifdef ASH_MATH_SUPPORT
/* The generated file arith.c has been replaced with a custom hand
 * written implementation written by Aaron Lehmann <[e-mail]>.  
 * This is now part of libbb, so that it can be used by all the shells 
 * in busybox. */
#define ARITH_NUM 257
#define ARITH_LPAREN 258
#define ARITH_RPAREN 259
#define ARITH_OR 260
#define ARITH_AND 261
#define ARITH_BOR 262
#define ARITH_BXOR 263
#define ARITH_BAND 264
#define ARITH_EQ 265
#define ARITH_NE 266
#define ARITH_LT 267
#define ARITH_GT 268
#define ARITH_GE 269
#define ARITH_LE 270
#define ARITH_LSHIFT 271
#define ARITH_RSHIFT 272
#define ARITH_ADD 273
#define ARITH_SUB 274
#define ARITH_MUL 275
#define ARITH_DIV 276
#define ARITH_REM 277
#define ARITH_UNARYMINUS 278
#define ARITH_UNARYPLUS 279
#define ARITH_NOT 280
#define ARITH_BNOT 281

static void expari (int);
#endif

static char *trap[NSIG];                /* trap handler commands */
static char sigmode[NSIG - 1];  /* current value of signal */
static char gotsig[NSIG - 1];           /* indicates specified signal received */
static int pendingsigs;                 /* indicates some signal received */

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

#ifdef JOBS
static int bgcmd (int, char **);
static int fgcmd (int, char **);
static int killcmd (int, char **);
#endif
static int bltincmd (int, char **);
static int cdcmd (int, char **);
static int breakcmd (int, char **);
#ifdef ASH_CMDCMD
static int commandcmd (int, char **);
#endif
static int dotcmd (int, char **);
static int evalcmd (int, char **);
static int execcmd (int, char **);
static int exitcmd (int, char **);
static int exportcmd (int, char **);
static int histcmd (int, char **);
static int hashcmd (int, char **);
static int helpcmd (int, char **);
static int jobscmd (int, char **);
static int localcmd (int, char **);
#ifndef BB_PWD
static int pwdcmd (int, char **);
#endif
static int readcmd (int, char **);
static int returncmd (int, char **);
static int setcmd (int, char **);
static int setvarcmd (int, char **);
static int shiftcmd (int, char **);
static int trapcmd (int, char **);
static int umaskcmd (int, char **);
#ifdef ASH_ALIAS
static int aliascmd (int, char **);
static int unaliascmd (int, char **);
#endif
static int unsetcmd (int, char **);
static int waitcmd (int, char **);
static int ulimitcmd (int, char **);
static int timescmd (int, char **);
#ifdef ASH_MATH_SUPPORT
static int letcmd (int, char **);
#endif
static int typecmd (int, char **);
#ifdef ASH_GETOPTS
static int getoptscmd (int, char **);
#endif

#ifndef BB_TRUE_FALSE
static int true_main (int, char **);
static int false_main (int, char **);
#endif

static void     setpwd (const char *, int);


#define BUILTIN_NOSPEC  "0"
#define BUILTIN_SPECIAL "1"
#define BUILTIN_REGULAR "2"
#define BUILTIN_ASSIGN  "4"
#define BUILTIN_SPEC_ASSG  "5"
#define BUILTIN_REG_ASSG   "6"

#define IS_BUILTIN_SPECIAL(builtincmd) ((builtincmd)->name[0] & 1)
#define IS_BUILTIN_REGULAR(builtincmd) ((builtincmd)->name[0] & 2)
#define IS_BUILTIN_ASSIGN(builtincmd) ((builtincmd)->name[0] & 4)

struct builtincmd {
	const char *name;
	int (*const builtinfunc) (int, char **);
	//unsigned flags;
};


/* It is CRUCIAL that this listing be kept in ascii order, otherwise
 * the binary search in find_builtin() will stop working. If you value
 * your kneecaps, you'll be sure to *make sure* that any changes made
 * to this array result in the listing remaining in ascii order. You
 * have been warned.
 */
static const struct builtincmd builtincmds[] = {
	{ BUILTIN_SPECIAL   ".", dotcmd },    /* first, see declare DOTCMD */
	{ BUILTIN_SPECIAL   ":", true_main },
#ifdef ASH_ALIAS
	{ BUILTIN_REG_ASSG  "alias", aliascmd },
#endif
#ifdef JOBS
	{ BUILTIN_REGULAR   "bg", bgcmd },
#endif
	{ BUILTIN_SPECIAL   "break", breakcmd },
	{ BUILTIN_SPECIAL   "builtin", bltincmd },
	{ BUILTIN_REGULAR   "cd", cdcmd },
	{ BUILTIN_NOSPEC    "chdir", cdcmd },
#ifdef ASH_CMDCMD
	{ BUILTIN_REGULAR   "command", commandcmd },
#endif
	{ BUILTIN_SPECIAL   "continue", breakcmd },
	{ BUILTIN_SPECIAL   "eval", evalcmd },
	{ BUILTIN_SPECIAL   "exec", execcmd },
	{ BUILTIN_SPECIAL   "exit", exitcmd },
	{ BUILTIN_SPEC_ASSG "export", exportcmd },
	{ BUILTIN_REGULAR   "false", false_main },
	{ BUILTIN_REGULAR   "fc", histcmd },
#ifdef JOBS
	{ BUILTIN_REGULAR   "fg", fgcmd },
#endif
#ifdef ASH_GETOPTS
	{ BUILTIN_REGULAR   "getopts", getoptscmd },
#endif
	{ BUILTIN_NOSPEC    "hash", hashcmd },
	{ BUILTIN_NOSPEC    "help", helpcmd },
	{ BUILTIN_REGULAR   "jobs", jobscmd },
#ifdef JOBS
	{ BUILTIN_REGULAR   "kill", killcmd },
#endif
#ifdef ASH_MATH_SUPPORT
	{ BUILTIN_REGULAR    "let", letcmd },
#endif
	{ BUILTIN_ASSIGN    "local", localcmd },
#ifndef BB_PWD
	{ BUILTIN_NOSPEC    "pwd", pwdcmd },
#endif
	{ BUILTIN_REGULAR   "read", readcmd },
	{ BUILTIN_SPEC_ASSG "readonly", exportcmd },
	{ BUILTIN_SPECIAL   "return", returncmd },
	{ BUILTIN_SPECIAL   "set", setcmd },
	{ BUILTIN_NOSPEC    "setvar", setvarcmd },
	{ BUILTIN_SPECIAL   "shift", shiftcmd },
	{ BUILTIN_SPECIAL   "times", timescmd },
	{ BUILTIN_SPECIAL   "trap", trapcmd },
	{ BUILTIN_REGULAR   "true", true_main },
	{ BUILTIN_NOSPEC    "type", typecmd },
	{ BUILTIN_NOSPEC    "ulimit", ulimitcmd },
	{ BUILTIN_REGULAR   "umask", umaskcmd },
#ifdef ASH_ALIAS
	{ BUILTIN_REGULAR   "unalias", unaliascmd },
#endif
	{ BUILTIN_SPECIAL   "unset", unsetcmd },
	{ BUILTIN_REGULAR   "wait", waitcmd },
};
#define NUMBUILTINS  (sizeof (builtincmds) / sizeof (struct builtincmd) )

static const struct builtincmd *DOTCMD = &builtincmds[0];
static struct builtincmd *BLTINCMD;
static struct builtincmd *EXECCMD;
static struct builtincmd *EVALCMD;

/* states */
#define JOBSTOPPED 1            /* all procs are stopped */
#define JOBDONE 2               /* all procs are completed */

/*
 * A job structure contains information about a job.  A job is either a
 * single process or a set of processes contained in a pipeline.  In the
 * latter case, pidlist will be non-NULL, and will point to a -1 terminated
 * array of pids.
 */

struct procstat {
	pid_t pid;              /* process id */
	int status;             /* status flags (defined above) */
	char *cmd;              /* text of command being run */
};


static int job_warning;         /* user was warned about stopped jobs */

#ifdef JOBS
static void setjobctl(int enable);
#else
#define setjobctl(on)   /* do nothing */
#endif


struct job {
	struct procstat ps0;    /* status of process */
	struct procstat *ps;    /* status or processes when more than one */
	short nprocs;           /* number of processes */
	short pgrp;             /* process group of this job */
	char state;             /* true if job is finished */
	char used;              /* true if this entry is in used */
	char changed;           /* true if status has changed */
#ifdef JOBS
	char jobctl;            /* job running under job control */
#endif
};

static struct job *jobtab;      /* array of jobs */
static int njobs;               /* size of array */
static int backgndpid = -1;     /* pid of last background process */
#ifdef JOBS
static int initialpgrp;         /* pgrp of shell on invocation */
static int curjob;              /* current job */
static int jobctl;
#endif
static int intreceived;

static struct job *makejob (const union node *, int);
static int forkshell (struct job *, const union node *, int);
static int waitforjob (struct job *);

static int docd (char *, int);
static char *getcomponent (void);
static void updatepwd (const char *);
static void getpwd (void);

static char *padvance (const char **, const char *);

static char nullstr[1];         /* zero length string */
static char *curdir = nullstr;          /* current working directory */
static char *cdcomppath;

static int
cdcmd(argc, argv)
	int argc;
	char **argv;
{
	const char *dest;
	const char *path;
	char *p;
	struct stat statb;
	int print = 0;

	nextopt(nullstr);
	if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME")) == NULL)
		error("HOME not set");
	if (*dest == '\0')
		dest = ".";
	if (dest[0] == '-' && dest[1] == '\0') {
		dest = bltinlookup("OLDPWD");
		if (!dest || !*dest) {
			dest = curdir;
		}
		print = 1;
		if (dest)
			print = 1;
		else
			dest = ".";
	}
	if (*dest == '/' || (path = bltinlookup("CDPATH")) == NULL)
		path = nullstr;
	while ((p = padvance(&path, dest)) != NULL) {
		if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
			if (!print) {
				/*
				 * XXX - rethink
				 */
				if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
					p += 2;
				print = strcmp(p, dest);
			}
			if (docd(p, print) >= 0)
				return 0;

		}
	}
	error("can't cd to %s", dest);
	/* NOTREACHED */
}


/*
 * Actually do the chdir.  In an interactive shell, print the
 * directory name if "print" is nonzero.
 */

static int
docd(dest, print)
	char *dest;
	int print;
{
	char *p;
	char *q;
	char *component;
	struct stat statb;
	int first;
	int badstat;

	TRACE(("docd(\"%s\", %d) called\n", dest, print));

	/*
	 *  Check each component of the path. If we find a symlink or
	 *  something we can't stat, clear curdir to force a getcwd()
	 *  next time we get the value of the current directory.
	 */
	badstat = 0;
	cdcomppath = sstrdup(dest);
	STARTSTACKSTR(p);
	if (*dest == '/') {
		STPUTC('/', p);
		cdcomppath++;
	}
	first = 1;
	while ((q = getcomponent()) != NULL) {
		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
			continue;
		if (! first)
			STPUTC('/', p);
		first = 0;
		component = q;
		while (*q)
			STPUTC(*q++, p);
		if (equal(component, ".."))
			continue;
		STACKSTRNUL(p);
		if ((lstat(stackblock(), &statb) < 0)
		    || (S_ISLNK(statb.st_mode)))  {
			/* print = 1; */
			badstat = 1;
			break;
		}
	}

	INTOFF;
	if (chdir(dest) < 0) {
		INTON;
		return -1;
	}
	updatepwd(badstat ? NULL : dest);
	INTON;
	if (print && iflag)
		printf(snlfmt, curdir);
	return 0;
}


/*
 * Get the next component of the path name pointed to by cdcomppath.
 * This routine overwrites the string pointed to by cdcomppath.
 */

static char *
getcomponent() {
	char *p;
	char *start;

	if ((p = cdcomppath) == NULL)
		return NULL;
	start = cdcomppath;
	while (*p != '/' && *p != '\0')
		p++;
	if (*p == '\0') {
		cdcomppath = NULL;
	} else {
		*p++ = '\0';
		cdcomppath = p;
	}
	return start;
}



/*
 * Update curdir (the name of the current directory) in response to a
 * cd command.  We also call hashcd to let the routines in exec.c know
 * that the current directory has changed.
 */

static void hashcd (void);

static void
updatepwd(const char *dir)
{
	char *new;
	char *p;
	size_t len;

	hashcd();                               /* update command hash table */

	/*
	 * If our argument is NULL, we don't know the current directory
	 * any more because we traversed a symbolic link or something
	 * we couldn't stat().
	 */
	if (dir == NULL || curdir == nullstr)  {
		setpwd(0, 1);
		return;
	}
	len = strlen(dir);
	cdcomppath = sstrdup(dir);
	STARTSTACKSTR(new);
	if (*dir != '/') {
		p = curdir;
		while (*p)
			STPUTC(*p++, new);
		if (p[-1] == '/')
			STUNPUTC(new);
	}
	while ((p = getcomponent()) != NULL) {
		if (equal(p, "..")) {
			while (new > stackblock() && (STUNPUTC(new), *new) != '/');
		} else if (*p != '\0' && ! equal(p, ".")) {
			STPUTC('/', new);
			while (*p)
				STPUTC(*p++, new);
		}
	}
	if (new == stackblock())
		STPUTC('/', new);
	STACKSTRNUL(new);
	setpwd(stackblock(), 1);
}


#ifndef BB_PWD
static int
pwdcmd(argc, argv)
	int argc;
	char **argv;
{
	printf(snlfmt, curdir);
	return 0;
}
#endif

/*
 * Find out what the current directory is. If we already know the current
 * directory, this routine returns immediately.