code: plan9front

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auth/box: -s, -. flags

-. decides where we chdir to before execing, we can't
sit where we are because our directory may not exist.
If not specified we go to '/'.

-s is used to source a rc script instead of execing cmd.
This is primarily to enable:
	'#!/bin/auth/box -s'
Shebang line size is a bit tight(32), so we have this shorthand
to use rc along with setting up the required namespace components.

--- a/sys/man/8/auth

+++ b/sys/man/8/auth

@@ -296,7 +296,11 @@

 the child namespace; the

 .B -e

 flag specifies a string of driver

-characters to keep.

+characters to keep. The

+.B -s

+flag gives a base set of namespace

+components, ones expected by rc, then passes

+the first argument as a script file to rc.

 .PP

 .I As

 executes

--- a/sys/src/cmd/auth/box.c

+++ b/sys/src/cmd/auth/box.c

@@ -10,11 +10,11 @@

 	char dash[4] = { '-' };

 	if(debug){

-		if(flag & MCREATE){

+		if(flag & MCREATE)

 			dash[2] = 'c';

-			flag &= ~MCREATE;

-		}

+

 		switch(flag){

+		case MCREATE|MREPL:

 		case MREPL:

 			dash[0] = ' ';

 			if(dash[2] == 'c')

@@ -133,10 +133,24 @@

 		sysfatal("/mnt/d mount setup: %r");

 }

+static char *parts[256];

+static int  mflags[nelem(parts)];

+static int  nparts;

+static char *rc[] = { "/bin/rc", nil , nil};

+

+static void

+push(char *path, int flag)

+{

+	if(nparts == nelem(parts))

+		sysfatal("component overflow");

+	parts[nparts] = path;

+	mflags[nparts++] = flag;

+}

+

 void

 usage(void)

 {

-	fprint(2, "usage %s: [ -d ] [ -r file ] [ -c dir ] [ -e devs ] cmd args...\n", argv0);

+	fprint(2, "usage %s: [ -d ] [ -r file ] [ -c dir ] [ -e devs ] [ -. path ] cmd args...\n", argv0);

 	exits("usage");

 }

@@ -143,16 +157,16 @@

 void

 main(int argc, char **argv)

 {

-	char *b;

-	Dir *d;

 	char devs[1024];

 	int dfd;

-	char *parts[256];

-	int mflags[256];

-	int nparts;

+	char *path;

+	char *a;

+	int sflag;

 	nparts = 0;

+	path = "/";

 	memset(devs, 0, sizeof devs);

+	sflag = 0;

 	ARGBEGIN{

 	case 'D':

 		debug++;

@@ -160,35 +174,48 @@

 		debug++;

 		break;

 	case 'r':

-		parts[nparts] = EARGF(usage());

-		mflags[nparts++] = MREPL;

+		a = EARGF(usage());

+		push(a, MREPL);

 		break;

 	case 'c':

-		parts[nparts] = EARGF(usage());

-		mflags[nparts++] = MCREATE|MREPL;

+		a = EARGF(usage());

+		push(a, MREPL|MCREATE);

 		break;

 	case 'e':

 		snprint(devs, sizeof devs, "%s%s", devs, EARGF(usage()));

 		break;

+	case '.':

+		path = EARGF(usage());

+		break;

+	case 's':

+		sflag = 1;

+		break;

 	default:

 		usage();

 		break;

 	}ARGEND

+

 	if(argc == 0)

 		usage();

-	b = argv[0];

-	d = dirstat(b);

-	if(d == nil){

-		b = smprint("/bin/%s", b);

-		d = dirstat(b);

-		if(d == nil)

-			sysfatal("could not stat %s %r", argv[0]);

+	if(sflag){

+		snprint(devs, sizeof devs, "%s%s", devs, "|d");

+		push("/srv", MREPL|MCREATE);

+		push("/env", MREPL|MCREATE);

+		push("/rc", MREPL);

+		push("/bin", MREPL);

+		push(argv[0], MREPL);

+		rc[1] = argv[0];

+		argv = rc;

+	} else {

+		if(access(argv[0], AEXIST) == -1){

+			if((argv[0] = smprint("/bin/%s", argv[0])) == nil)

+				sysfatal("smprint: %r");

+			if(access(argv[0], AEXIST) == -1)

+				sysfatal("could not stat %s %r", argv[0]);

+		}

+		push(argv[0], MREPL);

 	}

-	free(d);

-	parts[nparts] = b;

-	mflags[nparts++] = MREPL;

-	argv[0] = b;

 	rfork(RFNAMEG|RFFDG);

 	skelfs();

@@ -210,5 +237,9 @@

 			sysfatal("could not write chdev: %r");

 	}

 	close(dfd);

+

+	if(chdir(path) < 0)

+		sysfatal("can not cd to %s", path);

 	exec(argv[0], argv);

+	sysfatal("exec: %r");

 }