ash.c

手机嵌入式Linux下可用的busybox源码

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 BB_FEATURE_ASH_JOB_CONTROL
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 CONFIG_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 **);
static int pwdcmd(int, char **);
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 CONFIG_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 CONFIG_ASH_MATH_SUPPORT
static int letcmd(int, char **);
#endif
static int typecmd(int, char **);

#ifdef CONFIG_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 CONFIG_ASH_ALIAS
	{BUILTIN_REG_ASSG "alias", aliascmd},
#endif
#ifdef BB_FEATURE_ASH_JOB_CONTROL
	{BUILTIN_REGULAR "bg", bgcmd},
#endif
	{BUILTIN_SPECIAL "break", breakcmd},
	{BUILTIN_SPECIAL "builtin", bltincmd},
	{BUILTIN_REGULAR "cd", cdcmd},
	{BUILTIN_NOSPEC "chdir", cdcmd},
#ifdef CONFIG_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 BB_FEATURE_ASH_JOB_CONTROL
	{BUILTIN_REGULAR "fg", fgcmd},
#endif
#ifdef CONFIG_ASH_GETOPTS
	{BUILTIN_REGULAR "getopts", getoptscmd},
#endif
	{BUILTIN_NOSPEC "hash", hashcmd},
	{BUILTIN_NOSPEC "help", helpcmd},
	{BUILTIN_REGULAR "jobs", jobscmd},
#ifdef BB_FEATURE_ASH_JOB_CONTROL
	{BUILTIN_REGULAR "kill", killcmd},
#endif
#ifdef CONFIG_ASH_MATH_SUPPORT
	{BUILTIN_REGULAR "let", letcmd},
#endif
	{BUILTIN_ASSIGN "local", localcmd},
	{BUILTIN_NOSPEC "pwd", pwdcmd},
	{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 CONFIG_ASH_ALIAS
	{BUILTIN_REGULAR "unalias", unaliascmd},
#endif
	{BUILTIN_SPECIAL "unset", unsetcmd},
	{BUILTIN_REGULAR "wait", waitcmd},
};

#define NUMBUILTINS  (sizeof (builtincmds) / sizeof (struct builtincmd) )

#define 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 BB_FEATURE_ASH_JOB_CONTROL
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 BB_FEATURE_ASH_JOB_CONTROL
	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 BB_FEATURE_ASH_JOB_CONTROL
static int initialpgrp;	/* pgrp of shell on invocation */
static int curjob;		/* current job */
static int jobctl;
#endif

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 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 int cdcmd(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 */
}


/*
 * 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 inline void updatepwd(const char *dir)
{
	hashcd();			/* update command hash table */

	/*
	 * If our argument is NULL, we don't know the current directory
	 */
	if (dir == NULL || curdir == nullstr) {
		setpwd(0, 1);
	} else {
		setpwd(dir, 1);
	}
}

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

static int docd(char *dest, int print)
{
	TRACE(("docd(\"%s\", %d) called\n", dest, print));
	INTOFF;
	if (chdir(dest) < 0) {
		INTON;
		return -1;
	}
	updatepwd(dest);
	INTON;
	if (print && iflag)
		puts(curdir);
	return 0;
}


static int pwdcmd(int argc, char **argv)
{
	puts(curdir);
	return 0;
}

/* Ask system the current directory */
static void getpwd(void)
{
	curdir = xgetcwd(0);
	if (curdir == 0)
		curdir = nullstr;
}

static void setpwd(const char *val, int setold)
{
	char *cated = NULL;

	if (setold) {
		setvar("OLDPWD", curdir, VEXPORT);
	}
	INTOFF;
	if (curdir != nullstr) {
		if (val != NULL && *val != '/')
			val = cated = concat_path_file(curdir, val);
		free(curdir);
	}
	if (!val)
		getpwd();
	else
		curdir = simplify_path(val);
	free(cated);
	INTON;
	setvar("PWD", curdir, VEXPORT);
}

/*
 * Errors and exceptions.
 */

/*
 * Code to handle exceptions in C.
 */

/*
 * We enclose jmp_buf in a structure so that we can declare pointers to
 * jump locations.  The global variable handler contains the location to
 * jump to when an exception occurs, and the global variable exception
 * contains a code identifying the exeception.  To implement nested
 * exception handlers, the user should save the value of handler on entry
 * to an inner scope, set handler to point to a jmploc structure for the
 * inner scope, and restore handler on exit from the scope.
 */

struct jmploc {
	jmp_buf loc;
};

/* exceptions */
#define EXINT 0			/* SIGINT received */
#define EXERROR 1		/* a generic error */
#define EXSHELLPROC 2	/* execute a shell procedure */
#define EXEXEC 3		/* command execution failed */
#define EXREDIR 4		/* redirection error */

static struct jmploc *handler;
static int exception;

static void exverror(int, const char *, va_list)
	__attribute__ ((__noreturn__));

/*
 * Called to raise an exception.  Since C doesn't include exceptions, we
 * just do a longjmp to the exception handler.  The type of exception is
 * stored in the global variable "exception".
 */

static void exraise(int) __attribute__ ((__noreturn__));

static void exraise(int e)
{
#ifdef DEBUG
	if (handler == NULL)
		abort();
#endif
	flushall();
	exception = e;
	longjmp(handler->loc, 1);
}


/*
 * Called from trap.c when a SIGINT is received.  (If the user specifies
 * that SIGINT is to be trapped or ignored using the trap builtin, then
 * this routine is not called.)  Suppressint is nonzero when interrupts
 * are held using the INTOFF macro.  The call to _exit is necessary because
 * there is a short period after a fork before the signal handlers are
 * set to the appropriate value for the child.  (The test for iflag is
 * just defensive programming.)
 */

static void onint(void)
{
	sigset_t mysigset;

	if (suppressint) {
		intpending++;
		return;
	}
	intpending = 0;
	sigemptyset(&mysigset);
	sigprocmask(SIG_SETMASK, &mysigset, NULL);
	if (!(rootshell && iflag)) {
		signal(SIGINT, SIG_DFL);
		raise(SIGINT);
	}
	exraise(EXINT);
	/* NOTREACHED */
}


static char *commandname;	/* currently executing command */

/*
 * Exverror is called to raise the error exception.  If the first argument
 * is not NULL then error prints an error message using printf style
 * formatting.  It then raises the error exception.
 */
static void exverror(int cond, const char *msg, va_list ap)
{
	CLEAR_PENDING_INT;
	INTOFF;

#ifdef DEBUG
	if (msg)
		TRACE(("exverror(%d, \"%s\") pid=%d\n", cond, msg, getpid()));
	else
		TRACE(("exverror(%d, NULL) pid=%d\n", cond, getpid()));
#endif
	if (msg) {
		if (commandname)
			out2fmt("%s: ", commandname);
		vfprintf(stderr, msg, ap);
		out2c('\n');
	}
	exraise(cond);
	/* NOTREACHED */
}


static void error(const char *msg, ...)
{
	va_list ap;

	va_start(ap, msg);
	exverror(EXERROR, msg, ap);
	/* NOTREACHED */
	va_end(ap);
}


static void exerror(int cond, const char *msg, ...)
{
	va_list ap;

	va_start(ap, msg);
	exverror(cond, msg, ap);
	/* NOTREACHED */
	va_end(ap);
}



/*
 * Table of error messages.
 */

struct errname {
	short errcode;		/* error number */
	short action;		/* operation which encountered the error */
};

/*
 * Types of operations (passed to the errmsg routine).
 */

#define E_OPEN 01		/* opening a file */
#define E_CREAT 02		/* creating a file */
#define E_EXEC 04		/* executing a program */

#define ALL (E_OPEN|E_CREAT|E_EXEC)

static const struct errname errormsg[] = {