ash.c

手机嵌入式Linux下可用的busybox源码

	/* 224    94  "^" */ CWORD_CWORD_CWORD_CWORD,
	/* 225    95  "_" */ CWORD_CWORD_CWORD_CWORD,
	/* 226    96  "`" */ CBQUOTE_CBQUOTE_CWORD_CBQUOTE,
	/* 227    97  "a" */ CWORD_CWORD_CWORD_CWORD,
	/* 228    98  "b" */ CWORD_CWORD_CWORD_CWORD,
	/* 229    99  "c" */ CWORD_CWORD_CWORD_CWORD,
	/* 230   100  "d" */ CWORD_CWORD_CWORD_CWORD,
	/* 231   101  "e" */ CWORD_CWORD_CWORD_CWORD,
	/* 232   102  "f" */ CWORD_CWORD_CWORD_CWORD,
	/* 233   103  "g" */ CWORD_CWORD_CWORD_CWORD,
	/* 234   104  "h" */ CWORD_CWORD_CWORD_CWORD,
	/* 235   105  "i" */ CWORD_CWORD_CWORD_CWORD,
	/* 236   106  "j" */ CWORD_CWORD_CWORD_CWORD,
	/* 237   107  "k" */ CWORD_CWORD_CWORD_CWORD,
	/* 238   108  "l" */ CWORD_CWORD_CWORD_CWORD,
	/* 239   109  "m" */ CWORD_CWORD_CWORD_CWORD,
	/* 240   110  "n" */ CWORD_CWORD_CWORD_CWORD,
	/* 241   111  "o" */ CWORD_CWORD_CWORD_CWORD,
	/* 242   112  "p" */ CWORD_CWORD_CWORD_CWORD,
	/* 243   113  "q" */ CWORD_CWORD_CWORD_CWORD,
	/* 244   114  "r" */ CWORD_CWORD_CWORD_CWORD,
	/* 245   115  "s" */ CWORD_CWORD_CWORD_CWORD,
	/* 246   116  "t" */ CWORD_CWORD_CWORD_CWORD,
	/* 247   117  "u" */ CWORD_CWORD_CWORD_CWORD,
	/* 248   118  "v" */ CWORD_CWORD_CWORD_CWORD,
	/* 249   119  "w" */ CWORD_CWORD_CWORD_CWORD,
	/* 250   120  "x" */ CWORD_CWORD_CWORD_CWORD,
	/* 251   121  "y" */ CWORD_CWORD_CWORD_CWORD,
	/* 252   122  "z" */ CWORD_CWORD_CWORD_CWORD,
	/* 253   123  "{" */ CWORD_CWORD_CWORD_CWORD,
	/* 254   124  "|" */ CSPCL_CWORD_CWORD_CWORD,
	/* 255   125  "}" */ CENDVAR_CENDVAR_CWORD_CENDVAR,
	/* 256   126  "~" */ CWORD_CCTL_CCTL_CWORD,
	/* 257   127      */ CWORD_CWORD_CWORD_CWORD,
};

#endif							/* USE_SIT_FUNCTION */


/* first char is indicating which tokens mark the end of a list */
static const char *const tokname_array[] = {
	"\1end of file",
	"\0newline",
	"\0redirection",
	"\0word",
	"\0assignment",
	"\0;",
	"\0&",
	"\0&&",
	"\0||",
	"\0|",
	"\0(",
	"\1)",
	"\1;;",
	"\1`",
#define KWDOFFSET 14
	/* the following are keywords */
	"\0!",
	"\0case",
	"\1do",
	"\1done",
	"\1elif",
	"\1else",
	"\1esac",
	"\1fi",
	"\0for",
	"\0if",
	"\0in",
	"\1then",
	"\0until",
	"\0while",
	"\0{",
	"\1}",
};

static const char *tokname(int tok)
{
	static char buf[16];

	if (tok >= TSEMI)
		buf[0] = '"';
	sprintf(buf + (tok >= TSEMI), "%s%c",
			tokname_array[tok] + 1, (tok >= TSEMI ? '"' : 0));
	return buf;
}

static int plinno = 1;	/* input line number */

static int parselleft;	/* copy of parsefile->lleft */

static struct parsefile basepf;	/* top level input file */
static char basebuf[BUFSIZ];	/* buffer for top level input file */
static struct parsefile *parsefile = &basepf;	/* current input file */

/*
 * NEOF is returned by parsecmd when it encounters an end of file.  It
 * must be distinct from NULL, so we use the address of a variable that
 * happens to be handy.
 */

static int tokpushback;	/* last token pushed back */

#define NEOF ((union node *)&tokpushback)
static int checkkwd;	/* 1 == check for kwds, 2 == also eat newlines */


static void error(const char *, ...) __attribute__ ((__noreturn__));
static void exerror(int, const char *, ...) __attribute__ ((__noreturn__));
static void shellexec(char **, char **, const char *, int)
	__attribute__ ((noreturn));
static void exitshell(int) __attribute__ ((noreturn));

static int goodname(const char *);
static void ignoresig(int);
static void onsig(int);
static void dotrap(void);
static int decode_signal(const char *, int);

static void setparam(char **);
static void freeparam(volatile struct shparam *);

/* reasons for skipping commands (see comment on breakcmd routine) */
#define SKIPBREAK       1
#define SKIPCONT        2
#define SKIPFUNC        3
#define SKIPFILE        4

/* values of cmdtype */
#define CMDUNKNOWN -1	/* no entry in table for command */
#define CMDNORMAL 0		/* command is an executable program */
#define CMDBUILTIN 1	/* command is a shell builtin */
#define CMDFUNCTION 2	/* command is a shell function */

#define DO_ERR  1		/* find_command prints errors */
#define DO_ABS  2		/* find_command checks absolute paths */
#define DO_NOFUN        4	/* find_command ignores functions */
#define DO_BRUTE        8	/* find_command ignores hash table */

/*
 * Shell variables.
 */

/* flags */
#define VEXPORT         0x01	/* variable is exported */
#define VREADONLY       0x02	/* variable cannot be modified */
#define VSTRFIXED       0x04	/* variable struct is staticly allocated */
#define VTEXTFIXED      0x08	/* text is staticly allocated */
#define VSTACK          0x10	/* text is allocated on the stack */
#define VUNSET          0x20	/* the variable is not set */
#define VNOFUNC         0x40	/* don't call the callback function */


struct var {
	struct var *next;	/* next entry in hash list */
	int flags;			/* flags are defined above */
	char *text;			/* name=value */
	void (*func) (const char *);
	/* function to be called when  */
	/* the variable gets set/unset */
};

struct localvar {
	struct localvar *next;	/* next local variable in list */
	struct var *vp;		/* the variable that was made local */
	int flags;			/* saved flags */
	char *text;			/* saved text */
};


#if defined(__GLIBC__) && __GLIBC__ >= 2 && !defined(FNMATCH_BROKEN)
#define rmescapes(p) _rmescapes((p), 0)
static char *_rmescapes(char *, int);
#else
static void rmescapes(char *);
#endif

static int casematch(union node *, const char *);
static void clearredir(void);
static void popstring(void);
static void readcmdfile(const char *);

static int number(const char *);
static int is_number(const char *, int *num);
static char *single_quote(const char *);
static int nextopt(const char *);

static void redirect(union node *, int);
static void popredir(void);
static int dup_as_newfd(int, int);

static void changepath(const char *newval);
static void getoptsreset(const char *value);


static int parsenleft;	/* copy of parsefile->nleft */
static char *parsenextc;	/* copy of parsefile->nextc */
static int rootpid;		/* pid of main shell */
static int rootshell;	/* true if we aren't a child of the main shell */

static const char spcstr[] = " ";
static const char snlfmt[] = "%s\n";

static int sstrnleft;
static int herefd = -1;

static struct localvar *localvars;

static struct var vifs;
static struct var vmail;
static struct var vmpath;
static struct var vpath;
static struct var vps1;
static struct var vps2;
static struct var voptind;

#ifdef BB_LOCALE_SUPPORT
static struct var vlc_all;
static struct var vlc_ctype;
#endif

struct varinit {
	struct var *var;
	int flags;
	const char *text;
	void (*func) (const char *);
};

static const char defpathvar[] =
	"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin";
#define defpath (defpathvar + 5)

#ifdef IFS_BROKEN
static const char defifsvar[] = "IFS= \t\n";

#define defifs (defifsvar + 4)
#else
static const char defifs[] = " \t\n";
#endif

static const struct varinit varinit[] = {
#ifdef IFS_BROKEN
	{&vifs, VSTRFIXED | VTEXTFIXED, defifsvar,
#else
	{&vifs, VSTRFIXED | VTEXTFIXED | VUNSET, "IFS=",
#endif
	 NULL},
	{&vmail, VSTRFIXED | VTEXTFIXED | VUNSET, "MAIL=",
	 NULL},
	{&vmpath, VSTRFIXED | VTEXTFIXED | VUNSET, "MAILPATH=",
	 NULL},
	{&vpath, VSTRFIXED | VTEXTFIXED, defpathvar,
	 changepath},
#if defined(BB_FEATURE_COMMAND_EDITING) && defined(BB_FEATURE_SH_FANCY_PROMPT)
	{&vps1, VSTRFIXED | VTEXTFIXED, "PS1=\\w \\$ ",
	 NULL},
#endif							/* else vps1 depends on uid */
	{&vps2, VSTRFIXED | VTEXTFIXED, "PS2=> ",
	 NULL},
	{&voptind, VSTRFIXED | VTEXTFIXED, "OPTIND=1",
	 getoptsreset},
#ifdef BB_LOCALE_SUPPORT
	{&vlc_all, VSTRFIXED | VTEXTFIXED | VUNSET, "LC_ALL=",
	 change_lc_all},
	{&vlc_ctype, VSTRFIXED | VTEXTFIXED | VUNSET, "LC_CTYPE=",
	 change_lc_ctype},
#endif
	{NULL, 0, NULL,
	 NULL}
};

#define VTABSIZE 39

static struct var *vartab[VTABSIZE];

/*
 * The following macros access the values of the above variables.
 * They have to skip over the name.  They return the null string
 * for unset variables.
 */

#define ifsval()        (vifs.text + 4)
#define ifsset()        ((vifs.flags & VUNSET) == 0)
#define mailval()       (vmail.text + 5)
#define mpathval()      (vmpath.text + 9)
#define pathval()       (vpath.text + 5)
#define ps1val()        (vps1.text + 4)
#define ps2val()        (vps2.text + 4)
#define optindval()     (voptind.text + 7)

#define mpathset()      ((vmpath.flags & VUNSET) == 0)

static void initvar(void);
static void setvar(const char *, const char *, int);
static void setvareq(char *, int);
static void listsetvar(struct strlist *);
static const char *lookupvar(const char *);
static const char *bltinlookup(const char *);
static char **environment(void);
static int showvarscmd(int, char **);
static void mklocal(char *);
static void poplocalvars(void);
static int unsetvar(const char *);
static int varequal(const char *, const char *);


static char *arg0;		/* value of $0 */
static struct shparam shellparam;	/* current positional parameters */
static char **argptr;	/* argument list for builtin commands */
static char *optionarg;	/* set by nextopt (like getopt) */
static char *optptr;	/* used by nextopt */
static char *minusc;	/* argument to -c option */


#ifdef CONFIG_ASH_ALIAS

#define ALIASINUSE      1
#define ALIASDEAD       2

#define ATABSIZE 39

struct alias {
	struct alias *next;
	char *name;
	char *val;
	int flag;
};

static struct alias *atab[ATABSIZE];

static void setalias(char *, char *);
static struct alias **hashalias(const char *);
static struct alias *freealias(struct alias *);
static struct alias **__lookupalias(const char *);

static void setalias(char *name, char *val)
{
	struct alias *ap, **app;

	app = __lookupalias(name);
	ap = *app;
	INTOFF;
	if (ap) {
		if (!(ap->flag & ALIASINUSE)) {
			free(ap->val);
		}
		ap->val = xstrdup(val);
		ap->flag &= ~ALIASDEAD;
	} else {
		/* not found */
		ap = xmalloc(sizeof(struct alias));
		ap->name = xstrdup(name);
		ap->val = xstrdup(val);
		ap->flag = 0;
		ap->next = 0;
		*app = ap;
	}
	INTON;
}

static int unalias(char *name)
{
	struct alias **app;

	app = __lookupalias(name);

	if (*app) {
		INTOFF;
		*app = freealias(*app);
		INTON;
		return (0);
	}

	return (1);
}

static void rmaliases(void)
{
	struct alias *ap, **app;
	int i;

	INTOFF;
	for (i = 0; i < ATABSIZE; i++) {
		app = &atab[i];
		for (ap = *app; ap; ap = *app) {
			*app = freealias(*app);
			if (ap == *app) {
				app = &ap->next;
			}
		}
	}
	INTON;
}

static void printalias(const struct alias *ap)
{
	char *p;

	p = single_quote(ap->val);
	printf("alias %s=%s\n", ap->name, p);
	stunalloc(p);
}


/*
 * TODO - sort output
 */
static int aliascmd(int argc, char **argv)
{
	char *n, *v;
	int ret = 0;
	struct alias *ap;

	if (argc == 1) {
		int i;

		for (i = 0; i < ATABSIZE; i++)
			for (ap = atab[i]; ap; ap = ap->next) {
				printalias(ap);
			}
		return (0);
	}
	while ((n = *++argv) != NULL) {
		if ((v = strchr(n + 1, '=')) == NULL) {	/* n+1: funny ksh stuff */
			if ((ap = *__lookupalias(n)) == NULL) {
				out2fmt("%s: %s not found\n", "alias", n);
				ret = 1;
			} else
				printalias(ap);
		} else {
			*v++ = '\0';
			setalias(n, v);
		}
	}

	return (ret);
}

static int unaliascmd(int argc, char **argv)
{
	int i;

	while ((i = nextopt("a")) != '\0') {
		if (i == 'a') {
			rmaliases();
			return (0);
		}
	}
	for (i = 0; *argptr; argptr++) {
		if (unalias(*argptr)) {
			out2fmt("%s: %s not found\n", "unalias", *argptr);
			i = 1;
		}
	}

	return (i);
}

static struct alias **hashalias(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;
	free(ap->name);
	free(ap->val);
	free(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 CONFIG_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. */