lib/self_exec.c

/* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: t -*- */
/*
 * self_exec.c: self_exec magic required to run child functions on uClinux
 *
 * Copyright (C) 2005 Paul J.Y. Lahaie <pjlahaie-at-steamballoon.com>
 *
 * 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 software was produced by Steamballoon Incorporated
 * 55 Byward Market Square, 2nd Floor North, Ottawa, ON K1N 9C3, Canada
 */

#ifdef UCLINUX

#define _GNU_SOURCE /* for asprintf */
#include <stdarg.h>
#include <string.h>
#include <stdio.h>
#include "test.h"

/* Set from parse_opts.c: */
char *child_args;	/* Arguments to child when -C is used */

static char *start_cwd;	/* Stores the starting directory for self_exec */

int asprintf(char **app, const char *fmt, ...)
{
        va_list ptr;
        int rv;
        char *p;

        /*
         * First iteration - find out size of buffer required and allocate it.
         */
        va_start(ptr, fmt);
        rv = vsnprintf(NULL, 0, fmt, ptr);
        va_end(ptr);

        p = malloc(++rv);                       /* allocate the buffer */
        *app = p;
        if (!p) {
                return -1;
        }

        /*
         * Second iteration - actually produce output.
         */
        va_start(ptr, fmt);
        rv = vsnprintf(p, rv, fmt, ptr);
        va_end(ptr);

        return rv;
}

void
maybe_run_child(void (*child)(), char *fmt, ...)
{
    va_list ap;
    char *child_dir;
    char *p, *tok;
    int *iptr, i, j;
    char *s;
    char **sptr;
    char *endptr;

    /* Store the current directory for later use. */
    start_cwd = getcwd(NULL, 0);

    if (child_args) {
	char *args = strdup(child_args);

	child_dir = strtok(args, ",");
	if (strlen(child_dir) == 0) {
	    tst_resm(TBROK, NULL, "Could not get directory from -C option");
	    tst_exit();
	}

	va_start(ap, fmt);

	for (p = fmt; *p; p++) {
	    tok = strtok(NULL, ",");
	    if (!tok || strlen(tok) == 0) {
		tst_resm(TBROK, "Invalid argument to -C option");
		tst_exit();
	    }

	    switch (*p) {
	    case 'd':
		iptr = va_arg(ap, int *);
		i = strtol(tok, &endptr, 10);
		if (*endptr != '\0') {
		    tst_resm(TBROK, "Invalid argument to -C option");
		    tst_exit();
		}
		*iptr = i;
		break;
	    case 'n':
		j = va_arg(ap, int);
		i = strtol(tok, &endptr, 10);
		if (*endptr != '\0') {
		    tst_resm(TBROK, "Invalid argument to -C option");
		    tst_exit();
		}
		if (j != i) {
		    va_end(ap);
		    return;
		}
		break;
	    case 's':
		s = va_arg(ap, char *);
		if (!strncpy(s, tok, strlen(tok)+1)) {
		    tst_resm(TBROK, "Could not strncpy for -C option");
		    tst_exit();
		}
		break;
	    case 'S':
		sptr = va_arg(ap, char **);
		*sptr = strdup(tok);
		if (!*sptr) {
		    tst_resm(TBROK, "Could not strdup for -C option");
		    tst_exit();
		}
		break;
	    default:
		tst_resm(TBROK, "Format string option %c not implemented", *p);
		tst_exit();
		break;
	    }
	}

	va_end(ap);

	if (chdir(child_dir) < 0) {
	    tst_resm(TBROK, "Could not change to %s for child", child_dir);
	    tst_exit();
	}

	(*child)();
	tst_resm(TWARN, "Child function returned unexpectedly");
	/* Exit here? or exit silently? */
    }
}

int
self_exec(char *argv0, char *fmt, ...)
{
    va_list ap;
    char *p;
    char *tmp_cwd;
    char *arg;
    int ival;
    char *str;

    if ((tmp_cwd = getcwd(NULL, 0)) == NULL) {
	tst_resm(TBROK, "Could not getcwd()");
	return -1;
    }

    arg = strdup( tmp_cwd );

    if (( arg = strdup( tmp_cwd ))  == NULL) {
	tst_resm(TBROK, "Could not produce self_exec string");
	return -1;
    }

    va_start(ap, fmt);

    for (p = fmt; *p; p++) {
	switch (*p) {
	case 'd':
	case 'n':
	    ival = va_arg(ap, int);
	    if (asprintf(&arg, "%s,%d", arg, ival) < 0) {
		tst_resm(TBROK, "Could not produce self_exec string");
		return -1;
	    }
	    break;
	case 's':
	case 'S':
	    str = va_arg(ap, char *);
	    if (asprintf(&arg, "%s,%s", arg, str) < 0) {
		tst_resm(TBROK, "Could not produce self_exec string");
		return -1;
	    }
	    break;
	default:
	    tst_resm(TBROK, "Format string option %c not implemented", *p);
	    return -1;
	    break;
	}
    }

    va_end(ap);

    if (chdir(start_cwd) < 0) {
	tst_resm(TBROK, "Could not change to %s for self_exec", start_cwd);
	return -1;
    }

    return execlp(argv0, argv0, "-C", arg, (char *) NULL);
}

#endif /* UCLINUX */