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show.c revision 1.31
      1  1.31  christos /*	$NetBSD: show.c,v 1.31 2016/02/28 23:12:23 christos Exp $	*/
      2  1.10       cgd 
      3   1.1       cgd /*-
      4   1.5       jtc  * Copyright (c) 1991, 1993
      5   1.5       jtc  *	The Regents of the University of California.  All rights reserved.
      6   1.1       cgd  *
      7   1.1       cgd  * This code is derived from software contributed to Berkeley by
      8   1.1       cgd  * Kenneth Almquist.
      9   1.1       cgd  *
     10   1.1       cgd  * Redistribution and use in source and binary forms, with or without
     11   1.1       cgd  * modification, are permitted provided that the following conditions
     12   1.1       cgd  * are met:
     13   1.1       cgd  * 1. Redistributions of source code must retain the above copyright
     14   1.1       cgd  *    notice, this list of conditions and the following disclaimer.
     15   1.1       cgd  * 2. Redistributions in binary form must reproduce the above copyright
     16   1.1       cgd  *    notice, this list of conditions and the following disclaimer in the
     17   1.1       cgd  *    documentation and/or other materials provided with the distribution.
     18  1.25       agc  * 3. Neither the name of the University nor the names of its contributors
     19   1.1       cgd  *    may be used to endorse or promote products derived from this software
     20   1.1       cgd  *    without specific prior written permission.
     21   1.1       cgd  *
     22   1.1       cgd  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23   1.1       cgd  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24   1.1       cgd  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25   1.1       cgd  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26   1.1       cgd  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27   1.1       cgd  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28   1.1       cgd  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29   1.1       cgd  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30   1.1       cgd  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31   1.1       cgd  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32   1.1       cgd  * SUCH DAMAGE.
     33   1.1       cgd  */
     34   1.1       cgd 
     35  1.15  christos #include <sys/cdefs.h>
     36   1.1       cgd #ifndef lint
     37  1.10       cgd #if 0
     38  1.11  christos static char sccsid[] = "@(#)show.c	8.3 (Berkeley) 5/4/95";
     39  1.10       cgd #else
     40  1.31  christos __RCSID("$NetBSD: show.c,v 1.31 2016/02/28 23:12:23 christos Exp $");
     41  1.10       cgd #endif
     42   1.1       cgd #endif /* not lint */
     43   1.1       cgd 
     44   1.1       cgd #include <stdio.h>
     45  1.11  christos #include <stdarg.h>
     46  1.26       dsl #include <stdlib.h>
     47  1.28  christos #include <unistd.h>
     48  1.11  christos 
     49   1.1       cgd #include "shell.h"
     50   1.1       cgd #include "parser.h"
     51   1.1       cgd #include "nodes.h"
     52   1.1       cgd #include "mystring.h"
     53  1.11  christos #include "show.h"
     54  1.23  christos #include "options.h"
     55  1.30  christos #ifndef SMALL
     56  1.30  christos #define DEFINE_NODENAMES
     57  1.30  christos #include "nodenames.h"
     58  1.30  christos #endif
     59   1.1       cgd 
     60   1.1       cgd 
     61  1.29  christos FILE *tracefile;
     62  1.29  christos 
     63   1.1       cgd #ifdef DEBUG
     64  1.29  christos static int shtree(union node *, int, int, char *, FILE*);
     65  1.29  christos static int shcmd(union node *, FILE *);
     66  1.29  christos static int sharg(union node *, FILE *);
     67  1.29  christos static int indent(int, char *, FILE *);
     68  1.23  christos static void trstring(char *);
     69   1.1       cgd 
     70  1.11  christos void
     71  1.23  christos showtree(union node *n)
     72   1.8       cgd {
     73  1.29  christos 	FILE *fp;
     74  1.29  christos 
     75  1.29  christos 	fp = tracefile ? tracefile : stdout;
     76  1.29  christos 
     77  1.29  christos 	trputs("showtree(");
     78  1.29  christos 		if (n == NULL)
     79  1.29  christos 			trputs("NULL");
     80  1.29  christos 		else if (n == NEOF)
     81  1.29  christos 			trputs("NEOF");
     82  1.29  christos 	trputs(") called\n");
     83  1.29  christos 	if (n != NULL && n != NEOF)
     84  1.29  christos 		shtree(n, 1, 1, NULL, fp);
     85   1.1       cgd }
     86   1.1       cgd 
     87   1.1       cgd 
     88  1.29  christos static int
     89  1.29  christos shtree(union node *n, int ind, int nl, char *pfx, FILE *fp)
     90   1.8       cgd {
     91   1.1       cgd 	struct nodelist *lp;
     92  1.18        pk 	const char *s;
     93  1.29  christos 	int len;
     94   1.1       cgd 
     95  1.29  christos 	if (n == NULL) {
     96  1.29  christos 		if (nl)
     97  1.29  christos 			fputc('\n', fp);
     98  1.29  christos 		return 0;
     99  1.29  christos 	}
    100   1.9  christos 
    101  1.29  christos 	len = indent(ind, pfx, fp);
    102  1.29  christos 	switch (n->type) {
    103   1.1       cgd 	case NSEMI:
    104   1.1       cgd 		s = "; ";
    105  1.29  christos 		len += 2;
    106   1.1       cgd 		goto binop;
    107   1.1       cgd 	case NAND:
    108   1.1       cgd 		s = " && ";
    109  1.29  christos 		len += 4;
    110   1.1       cgd 		goto binop;
    111   1.1       cgd 	case NOR:
    112   1.1       cgd 		s = " || ";
    113  1.29  christos 		len += 4;
    114   1.1       cgd binop:
    115  1.29  christos 		len += shtree(n->nbinary.ch1, 0, 0, NULL, fp);
    116  1.29  christos 		fputs(s, fp);
    117  1.29  christos 		if (len >= 60) {
    118  1.29  christos 			putc('\n', fp);
    119  1.29  christos 			len = indent(ind < 0 ? 2 : ind + 1, pfx, fp);
    120  1.29  christos 		}
    121  1.29  christos 		len += shtree(n->nbinary.ch2, 0, nl, NULL, fp);
    122   1.1       cgd 		break;
    123   1.1       cgd 	case NCMD:
    124  1.29  christos 		len += shcmd(n, fp);
    125  1.31  christos 		if (nl && len > 0)
    126  1.29  christos 			len = 0, putc('\n', fp);
    127   1.1       cgd 		break;
    128   1.1       cgd 	case NPIPE:
    129   1.1       cgd 		for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
    130  1.29  christos 			len += shcmd(lp->n, fp);
    131  1.29  christos 			if (lp->next) {
    132  1.29  christos 				len += 3, fputs(" | ", fp);
    133  1.29  christos 				if (len >= 60)  {
    134  1.29  christos 					fputc('\n', fp);
    135  1.29  christos 					len = indent(ind < 0 ? 2 : ind + 1,
    136  1.29  christos 					    pfx, fp);
    137  1.29  christos 				}
    138  1.29  christos 			}
    139   1.1       cgd 		}
    140   1.1       cgd 		if (n->npipe.backgnd)
    141  1.29  christos 			len += 2, fputs(" &", fp);
    142  1.29  christos 		if (nl || len >= 60)
    143  1.29  christos 			len = 0, fputc('\n', fp);
    144   1.1       cgd 		break;
    145   1.1       cgd 	default:
    146  1.29  christos #ifdef NODETYPENAME
    147  1.29  christos 		len += fprintf(fp, "<node type %d [%s]>", n->type,
    148  1.29  christos 		    NODETYPENAME(n->type));
    149  1.29  christos #else
    150  1.29  christos 		len += fprintf(fp, "<node type %d>", n->type);
    151  1.29  christos #endif
    152  1.29  christos 		if (nl)
    153  1.29  christos 			len = 0, putc('\n', fp);
    154   1.1       cgd 		break;
    155   1.1       cgd 	}
    156  1.29  christos 	return len;
    157   1.1       cgd }
    158   1.1       cgd 
    159   1.1       cgd 
    160   1.1       cgd 
    161  1.29  christos static int
    162  1.23  christos shcmd(union node *cmd, FILE *fp)
    163  1.11  christos {
    164   1.1       cgd 	union node *np;
    165   1.1       cgd 	int first;
    166  1.18        pk 	const char *s;
    167   1.1       cgd 	int dftfd;
    168  1.29  christos 	int len = 0;
    169   1.1       cgd 
    170   1.1       cgd 	first = 1;
    171   1.1       cgd 	for (np = cmd->ncmd.args ; np ; np = np->narg.next) {
    172   1.1       cgd 		if (! first)
    173  1.29  christos 			len++, fputc(' ', fp);
    174  1.29  christos 		len += sharg(np, fp);
    175   1.1       cgd 		first = 0;
    176   1.1       cgd 	}
    177   1.1       cgd 	for (np = cmd->ncmd.redirect ; np ; np = np->nfile.next) {
    178   1.1       cgd 		if (! first)
    179  1.29  christos 			len++, fputc(' ', fp);
    180   1.1       cgd 		switch (np->nfile.type) {
    181  1.29  christos 			case NTO:	s = ">";  dftfd = 1; len += 1; break;
    182  1.29  christos 			case NCLOBBER:	s = ">|"; dftfd = 1; len += 2; break;
    183  1.29  christos 			case NAPPEND:	s = ">>"; dftfd = 1; len += 2; break;
    184  1.29  christos 			case NTOFD:	s = ">&"; dftfd = 1; len += 2; break;
    185  1.29  christos 			case NFROM:	s = "<";  dftfd = 0; len += 1; break;
    186  1.29  christos 			case NFROMFD:	s = "<&"; dftfd = 0; len += 2; break;
    187  1.29  christos 			case NFROMTO:	s = "<>"; dftfd = 0; len += 2; break;
    188  1.31  christos 			case NXHERE:	/* FALLTHROUGH */
    189  1.31  christos 			case NHERE:	s = "<<"; dftfd = 0; len += 2; break;
    190  1.29  christos 			default:   s = "*error*"; dftfd = 0; len += 7; break;
    191   1.1       cgd 		}
    192   1.1       cgd 		if (np->nfile.fd != dftfd)
    193  1.29  christos 			len += fprintf(fp, "%d", np->nfile.fd);
    194   1.1       cgd 		fputs(s, fp);
    195   1.1       cgd 		if (np->nfile.type == NTOFD || np->nfile.type == NFROMFD) {
    196  1.29  christos 			len += fprintf(fp, "%d", np->ndup.dupfd);
    197  1.31  christos 		} else
    198  1.31  christos 		    if (np->nfile.type == NHERE || np->nfile.type == NXHERE) {
    199  1.31  christos 			if (np->nfile.type == NHERE)
    200  1.31  christos 				fputc('\\', fp);
    201  1.31  christos 			fputs("!!!\n", fp);
    202  1.31  christos 			fputs(np->nhere.doc->narg.text, fp);
    203  1.31  christos 			fputs("!!!", fp);
    204  1.31  christos 			len = 3;
    205   1.1       cgd 		} else {
    206  1.29  christos 			len += sharg(np->nfile.fname, fp);
    207   1.1       cgd 		}
    208   1.1       cgd 		first = 0;
    209   1.1       cgd 	}
    210  1.29  christos 	return len;
    211   1.1       cgd }
    212   1.1       cgd 
    213   1.1       cgd 
    214   1.1       cgd 
    215  1.29  christos static int
    216  1.23  christos sharg(union node *arg, FILE *fp)
    217  1.23  christos {
    218   1.1       cgd 	char *p;
    219   1.1       cgd 	struct nodelist *bqlist;
    220   1.1       cgd 	int subtype;
    221  1.29  christos 	int len = 0;
    222   1.1       cgd 
    223   1.1       cgd 	if (arg->type != NARG) {
    224  1.29  christos 		fprintf(fp, "<node type %d>\n", arg->type);
    225   1.1       cgd 		abort();
    226   1.1       cgd 	}
    227   1.1       cgd 	bqlist = arg->narg.backquote;
    228   1.1       cgd 	for (p = arg->narg.text ; *p ; p++) {
    229   1.1       cgd 		switch (*p) {
    230   1.1       cgd 		case CTLESC:
    231   1.1       cgd 			putc(*++p, fp);
    232  1.29  christos 			len++;
    233   1.1       cgd 			break;
    234   1.1       cgd 		case CTLVAR:
    235   1.1       cgd 			putc('$', fp);
    236   1.1       cgd 			putc('{', fp);
    237  1.29  christos 			len += 2;
    238   1.1       cgd 			subtype = *++p;
    239   1.9  christos 			if (subtype == VSLENGTH)
    240  1.29  christos 				len++, putc('#', fp);
    241   1.9  christos 
    242  1.29  christos 			while (*++p != '=')
    243  1.29  christos 				len++, putc(*p, fp);
    244   1.9  christos 
    245   1.1       cgd 			if (subtype & VSNUL)
    246  1.29  christos 				len++, putc(':', fp);
    247   1.9  christos 
    248   1.1       cgd 			switch (subtype & VSTYPE) {
    249   1.1       cgd 			case VSNORMAL:
    250   1.1       cgd 				putc('}', fp);
    251  1.29  christos 				len++;
    252   1.1       cgd 				break;
    253   1.1       cgd 			case VSMINUS:
    254   1.1       cgd 				putc('-', fp);
    255  1.29  christos 				len++;
    256   1.1       cgd 				break;
    257   1.1       cgd 			case VSPLUS:
    258   1.1       cgd 				putc('+', fp);
    259  1.29  christos 				len++;
    260   1.1       cgd 				break;
    261   1.1       cgd 			case VSQUESTION:
    262   1.1       cgd 				putc('?', fp);
    263  1.29  christos 				len++;
    264   1.1       cgd 				break;
    265   1.1       cgd 			case VSASSIGN:
    266   1.1       cgd 				putc('=', fp);
    267  1.29  christos 				len++;
    268   1.9  christos 				break;
    269   1.9  christos 			case VSTRIMLEFT:
    270   1.9  christos 				putc('#', fp);
    271  1.29  christos 				len++;
    272   1.9  christos 				break;
    273   1.9  christos 			case VSTRIMLEFTMAX:
    274   1.9  christos 				putc('#', fp);
    275   1.9  christos 				putc('#', fp);
    276  1.29  christos 				len += 2;
    277   1.9  christos 				break;
    278   1.9  christos 			case VSTRIMRIGHT:
    279   1.9  christos 				putc('%', fp);
    280  1.29  christos 				len++;
    281   1.9  christos 				break;
    282   1.9  christos 			case VSTRIMRIGHTMAX:
    283   1.9  christos 				putc('%', fp);
    284   1.9  christos 				putc('%', fp);
    285  1.29  christos 				len += 2;
    286   1.9  christos 				break;
    287   1.9  christos 			case VSLENGTH:
    288   1.1       cgd 				break;
    289   1.1       cgd 			default:
    290  1.29  christos 				len += fprintf(fp, "<subtype %d>", subtype);
    291   1.1       cgd 			}
    292   1.1       cgd 			break;
    293   1.1       cgd 		case CTLENDVAR:
    294   1.1       cgd 		     putc('}', fp);
    295  1.29  christos 		     len++;
    296   1.1       cgd 		     break;
    297   1.1       cgd 		case CTLBACKQ:
    298   1.1       cgd 		case CTLBACKQ|CTLQUOTE:
    299   1.1       cgd 			putc('$', fp);
    300   1.1       cgd 			putc('(', fp);
    301  1.29  christos 			len += shtree(bqlist->n, -1, 0, NULL, fp) + 3;
    302   1.1       cgd 			putc(')', fp);
    303   1.1       cgd 			break;
    304   1.1       cgd 		default:
    305   1.1       cgd 			putc(*p, fp);
    306  1.29  christos 			len++;
    307   1.1       cgd 			break;
    308   1.1       cgd 		}
    309   1.1       cgd 	}
    310  1.29  christos 	return len;
    311   1.1       cgd }
    312   1.1       cgd 
    313   1.1       cgd 
    314  1.29  christos static int
    315  1.23  christos indent(int amount, char *pfx, FILE *fp)
    316   1.8       cgd {
    317   1.1       cgd 	int i;
    318  1.29  christos 	int len = 0;
    319   1.1       cgd 
    320  1.29  christos 	/*
    321  1.29  christos 	 * in practice, pfx is **always** NULL
    322  1.29  christos 	 * but here, we assume if it were not, at least strlen(pfx) < 8
    323  1.29  christos 	 * if that is invalid, output will look messy
    324  1.29  christos 	 */
    325   1.1       cgd 	for (i = 0 ; i < amount ; i++) {
    326   1.1       cgd 		if (pfx && i == amount - 1)
    327   1.1       cgd 			fputs(pfx, fp);
    328   1.1       cgd 		putc('\t', fp);
    329  1.29  christos 		len |= 7;
    330  1.29  christos 		len++;
    331   1.1       cgd 	}
    332  1.29  christos 	return len;
    333   1.1       cgd }
    334   1.1       cgd #endif
    335   1.1       cgd 
    336   1.1       cgd 
    337   1.1       cgd 
    338   1.1       cgd /*
    339   1.1       cgd  * Debugging stuff.
    340   1.1       cgd  */
    341   1.1       cgd 
    342   1.1       cgd 
    343   1.1       cgd 
    344   1.1       cgd 
    345  1.12  christos #ifdef DEBUG
    346   1.8       cgd void
    347  1.23  christos trputc(int c)
    348   1.8       cgd {
    349  1.27  christos 	if (debug != 1 || !tracefile)
    350   1.1       cgd 		return;
    351   1.1       cgd 	putc(c, tracefile);
    352  1.12  christos }
    353   1.1       cgd #endif
    354   1.1       cgd 
    355  1.11  christos void
    356  1.11  christos trace(const char *fmt, ...)
    357  1.11  christos {
    358  1.11  christos #ifdef DEBUG
    359  1.11  christos 	va_list va;
    360  1.22       wiz 
    361  1.27  christos 	if (debug != 1 || !tracefile)
    362  1.23  christos 		return;
    363  1.11  christos 	va_start(va, fmt);
    364  1.23  christos 	(void) vfprintf(tracefile, fmt, va);
    365  1.11  christos 	va_end(va);
    366   1.1       cgd #endif
    367   1.1       cgd }
    368   1.1       cgd 
    369  1.24       dsl void
    370  1.24       dsl tracev(const char *fmt, va_list va)
    371  1.24       dsl {
    372  1.24       dsl #ifdef DEBUG
    373  1.28  christos 	va_list ap;
    374  1.27  christos 	if (debug != 1 || !tracefile)
    375  1.24       dsl 		return;
    376  1.28  christos 	va_copy(ap, va);
    377  1.28  christos 	(void) vfprintf(tracefile, fmt, ap);
    378  1.28  christos 	va_end(ap);
    379  1.24       dsl #endif
    380  1.24       dsl }
    381  1.24       dsl 
    382   1.1       cgd 
    383  1.12  christos #ifdef DEBUG
    384   1.7       cgd void
    385  1.23  christos trputs(const char *s)
    386   1.7       cgd {
    387  1.27  christos 	if (debug != 1 || !tracefile)
    388   1.1       cgd 		return;
    389   1.1       cgd 	fputs(s, tracefile);
    390   1.1       cgd }
    391   1.1       cgd 
    392   1.1       cgd 
    393   1.8       cgd static void
    394  1.23  christos trstring(char *s)
    395   1.8       cgd {
    396  1.13       tls 	char *p;
    397   1.1       cgd 	char c;
    398   1.1       cgd 
    399  1.27  christos 	if (debug != 1 || !tracefile)
    400   1.1       cgd 		return;
    401   1.1       cgd 	putc('"', tracefile);
    402   1.1       cgd 	for (p = s ; *p ; p++) {
    403   1.1       cgd 		switch (*p) {
    404   1.1       cgd 		case '\n':  c = 'n';  goto backslash;
    405   1.1       cgd 		case '\t':  c = 't';  goto backslash;
    406   1.1       cgd 		case '\r':  c = 'r';  goto backslash;
    407   1.1       cgd 		case '"':  c = '"';  goto backslash;
    408   1.1       cgd 		case '\\':  c = '\\';  goto backslash;
    409   1.1       cgd 		case CTLESC:  c = 'e';  goto backslash;
    410   1.1       cgd 		case CTLVAR:  c = 'v';  goto backslash;
    411   1.1       cgd 		case CTLVAR+CTLQUOTE:  c = 'V';  goto backslash;
    412   1.1       cgd 		case CTLBACKQ:  c = 'q';  goto backslash;
    413   1.1       cgd 		case CTLBACKQ+CTLQUOTE:  c = 'Q';  goto backslash;
    414   1.1       cgd backslash:	  putc('\\', tracefile);
    415   1.1       cgd 			putc(c, tracefile);
    416   1.1       cgd 			break;
    417   1.1       cgd 		default:
    418   1.1       cgd 			if (*p >= ' ' && *p <= '~')
    419   1.1       cgd 				putc(*p, tracefile);
    420   1.1       cgd 			else {
    421   1.1       cgd 				putc('\\', tracefile);
    422   1.1       cgd 				putc(*p >> 6 & 03, tracefile);
    423   1.1       cgd 				putc(*p >> 3 & 07, tracefile);
    424   1.1       cgd 				putc(*p & 07, tracefile);
    425   1.1       cgd 			}
    426   1.1       cgd 			break;
    427   1.1       cgd 		}
    428   1.1       cgd 	}
    429   1.1       cgd 	putc('"', tracefile);
    430  1.12  christos }
    431   1.1       cgd #endif
    432   1.1       cgd 
    433   1.1       cgd 
    434   1.7       cgd void
    435  1.23  christos trargs(char **ap)
    436   1.7       cgd {
    437   1.1       cgd #ifdef DEBUG
    438  1.27  christos 	if (debug != 1 || !tracefile)
    439   1.1       cgd 		return;
    440   1.1       cgd 	while (*ap) {
    441   1.1       cgd 		trstring(*ap++);
    442   1.1       cgd 		if (*ap)
    443   1.1       cgd 			putc(' ', tracefile);
    444   1.1       cgd 		else
    445   1.1       cgd 			putc('\n', tracefile);
    446   1.1       cgd 	}
    447   1.1       cgd #endif
    448   1.1       cgd }
    449   1.1       cgd 
    450   1.1       cgd 
    451  1.12  christos #ifdef DEBUG
    452   1.7       cgd void
    453  1.23  christos opentrace(void)
    454  1.23  christos {
    455   1.1       cgd 	char s[100];
    456  1.11  christos #ifdef O_APPEND
    457   1.1       cgd 	int flags;
    458  1.11  christos #endif
    459   1.1       cgd 
    460  1.24       dsl 	if (debug != 1) {
    461  1.23  christos 		if (tracefile)
    462  1.23  christos 			fflush(tracefile);
    463  1.23  christos 		/* leave open because libedit might be using it */
    464   1.1       cgd 		return;
    465  1.23  christos 	}
    466   1.5       jtc #ifdef not_this_way
    467  1.11  christos 	{
    468  1.11  christos 		char *p;
    469  1.11  christos 		if ((p = getenv("HOME")) == NULL) {
    470  1.11  christos 			if (geteuid() == 0)
    471  1.11  christos 				p = "/";
    472  1.11  christos 			else
    473  1.11  christos 				p = "/tmp";
    474  1.11  christos 		}
    475  1.11  christos 		scopy(p, s);
    476  1.11  christos 		strcat(s, "/trace");
    477   1.1       cgd 	}
    478   1.5       jtc #else
    479  1.28  christos 	snprintf(s, sizeof(s), "./trace.%d", (int)getpid());
    480   1.5       jtc #endif /* not_this_way */
    481  1.23  christos 	if (tracefile) {
    482  1.23  christos 		if (!freopen(s, "a", tracefile)) {
    483  1.23  christos 			fprintf(stderr, "Can't re-open %s\n", s);
    484  1.27  christos 			tracefile = NULL;
    485  1.23  christos 			debug = 0;
    486  1.23  christos 			return;
    487  1.23  christos 		}
    488  1.23  christos 	} else {
    489  1.23  christos 		if ((tracefile = fopen(s, "a")) == NULL) {
    490  1.23  christos 			fprintf(stderr, "Can't open %s\n", s);
    491  1.23  christos 			debug = 0;
    492  1.23  christos 			return;
    493  1.23  christos 		}
    494   1.1       cgd 	}
    495   1.1       cgd #ifdef O_APPEND
    496   1.1       cgd 	if ((flags = fcntl(fileno(tracefile), F_GETFL, 0)) >= 0)
    497   1.1       cgd 		fcntl(fileno(tracefile), F_SETFL, flags | O_APPEND);
    498   1.1       cgd #endif
    499  1.23  christos 	setlinebuf(tracefile);
    500   1.1       cgd 	fputs("\nTracing started.\n", tracefile);
    501  1.12  christos }
    502   1.5       jtc #endif /* DEBUG */
    503