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      1 /*	$OpenBSD: shf.c,v 1.16 2013/04/19 17:36:09 millert Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011,
      5  *		 2012, 2013, 2015, 2016, 2017
      6  *	mirabilos <m (at) mirbsd.org>
      7  *
      8  * Provided that these terms and disclaimer and all copyright notices
      9  * are retained or reproduced in an accompanying document, permission
     10  * is granted to deal in this work without restriction, including un-
     11  * limited rights to use, publicly perform, distribute, sell, modify,
     12  * merge, give away, or sublicence.
     13  *
     14  * This work is provided "AS IS" and WITHOUT WARRANTY of any kind, to
     15  * the utmost extent permitted by applicable law, neither express nor
     16  * implied; without malicious intent or gross negligence. In no event
     17  * may a licensor, author or contributor be held liable for indirect,
     18  * direct, other damage, loss, or other issues arising in any way out
     19  * of dealing in the work, even if advised of the possibility of such
     20  * damage or existence of a defect, except proven that it results out
     21  * of said person's immediate fault when using the work as intended.
     22  *-
     23  * Use %zX instead of %p and floating point isn't supported at all.
     24  */
     25 
     26 #include "sh.h"
     27 
     28 __RCSID("$MirOS: src/bin/mksh/shf.c,v 1.79 2017/04/12 17:08:49 tg Exp $");
     29 
     30 /* flags to shf_emptybuf() */
     31 #define EB_READSW	0x01	/* about to switch to reading */
     32 #define EB_GROW		0x02	/* grow buffer if necessary (STRING+DYNAMIC) */
     33 
     34 /*
     35  * Replacement stdio routines. Stdio is too flakey on too many machines
     36  * to be useful when you have multiple processes using the same underlying
     37  * file descriptors.
     38  */
     39 
     40 static int shf_fillbuf(struct shf *);
     41 static int shf_emptybuf(struct shf *, int);
     42 
     43 /*
     44  * Open a file. First three args are for open(), last arg is flags for
     45  * this package. Returns NULL if file could not be opened, or if a dup
     46  * fails.
     47  */
     48 struct shf *
     49 shf_open(const char *name, int oflags, int mode, int sflags)
     50 {
     51 	struct shf *shf;
     52 	ssize_t bsize =
     53 	    /* at most 512 */
     54 	    sflags & SHF_UNBUF ? (sflags & SHF_RD ? 1 : 0) : SHF_BSIZE;
     55 	int fd, eno;
     56 
     57 	/* Done before open so if alloca fails, fd won't be lost. */
     58 	shf = alloc(sizeof(struct shf) + bsize, ATEMP);
     59 	shf->areap = ATEMP;
     60 	shf->buf = (unsigned char *)&shf[1];
     61 	shf->bsize = bsize;
     62 	shf->flags = SHF_ALLOCS;
     63 	/* Rest filled in by reopen. */
     64 
     65 	fd = binopen3(name, oflags, mode);
     66 	if (fd < 0) {
     67 		eno = errno;
     68 		afree(shf, shf->areap);
     69 		errno = eno;
     70 		return (NULL);
     71 	}
     72 	if ((sflags & SHF_MAPHI) && fd < FDBASE) {
     73 		int nfd;
     74 
     75 		nfd = fcntl(fd, F_DUPFD, FDBASE);
     76 		eno = errno;
     77 		close(fd);
     78 		if (nfd < 0) {
     79 			afree(shf, shf->areap);
     80 			errno = eno;
     81 			return (NULL);
     82 		}
     83 		fd = nfd;
     84 	}
     85 	sflags &= ~SHF_ACCMODE;
     86 	sflags |= (oflags & O_ACCMODE) == O_RDONLY ? SHF_RD :
     87 	    ((oflags & O_ACCMODE) == O_WRONLY ? SHF_WR : SHF_RDWR);
     88 
     89 	return (shf_reopen(fd, sflags, shf));
     90 }
     91 
     92 /* helper function for shf_fdopen and shf_reopen */
     93 static void
     94 shf_open_hlp(int fd, int *sflagsp, const char *where)
     95 {
     96 	int sflags = *sflagsp;
     97 
     98 	/* use fcntl() to figure out correct read/write flags */
     99 	if (sflags & SHF_GETFL) {
    100 		int flags = fcntl(fd, F_GETFL, 0);
    101 
    102 		if (flags < 0)
    103 			/* will get an error on first read/write */
    104 			sflags |= SHF_RDWR;
    105 		else {
    106 			switch (flags & O_ACCMODE) {
    107 			case O_RDONLY:
    108 				sflags |= SHF_RD;
    109 				break;
    110 			case O_WRONLY:
    111 				sflags |= SHF_WR;
    112 				break;
    113 			case O_RDWR:
    114 				sflags |= SHF_RDWR;
    115 				break;
    116 			}
    117 		}
    118 		*sflagsp = sflags;
    119 	}
    120 
    121 	if (!(sflags & (SHF_RD | SHF_WR)))
    122 		internal_errorf(Tf_sD_s, where, "missing read/write");
    123 }
    124 
    125 /* Set up the shf structure for a file descriptor. Doesn't fail. */
    126 struct shf *
    127 shf_fdopen(int fd, int sflags, struct shf *shf)
    128 {
    129 	ssize_t bsize =
    130 	    /* at most 512 */
    131 	    sflags & SHF_UNBUF ? (sflags & SHF_RD ? 1 : 0) : SHF_BSIZE;
    132 
    133 	shf_open_hlp(fd, &sflags, "shf_fdopen");
    134 	if (shf) {
    135 		if (bsize) {
    136 			shf->buf = alloc(bsize, ATEMP);
    137 			sflags |= SHF_ALLOCB;
    138 		} else
    139 			shf->buf = NULL;
    140 	} else {
    141 		shf = alloc(sizeof(struct shf) + bsize, ATEMP);
    142 		shf->buf = (unsigned char *)&shf[1];
    143 		sflags |= SHF_ALLOCS;
    144 	}
    145 	shf->areap = ATEMP;
    146 	shf->fd = fd;
    147 	shf->rp = shf->wp = shf->buf;
    148 	shf->rnleft = 0;
    149 	shf->rbsize = bsize;
    150 	shf->wnleft = 0; /* force call to shf_emptybuf() */
    151 	shf->wbsize = sflags & SHF_UNBUF ? 0 : bsize;
    152 	shf->flags = sflags;
    153 	shf->errnosv = 0;
    154 	shf->bsize = bsize;
    155 	if (sflags & SHF_CLEXEC)
    156 		fcntl(fd, F_SETFD, FD_CLOEXEC);
    157 	return (shf);
    158 }
    159 
    160 /* Set up an existing shf (and buffer) to use the given fd */
    161 struct shf *
    162 shf_reopen(int fd, int sflags, struct shf *shf)
    163 {
    164 	ssize_t bsize =
    165 	    /* at most 512 */
    166 	    sflags & SHF_UNBUF ? (sflags & SHF_RD ? 1 : 0) : SHF_BSIZE;
    167 
    168 	shf_open_hlp(fd, &sflags, "shf_reopen");
    169 	if (!shf || !shf->buf || shf->bsize < bsize)
    170 		internal_errorf(Tf_sD_s, "shf_reopen", Tbad_bsize);
    171 
    172 	/* assumes shf->buf and shf->bsize already set up */
    173 	shf->fd = fd;
    174 	shf->rp = shf->wp = shf->buf;
    175 	shf->rnleft = 0;
    176 	shf->rbsize = bsize;
    177 	shf->wnleft = 0; /* force call to shf_emptybuf() */
    178 	shf->wbsize = sflags & SHF_UNBUF ? 0 : bsize;
    179 	shf->flags = (shf->flags & (SHF_ALLOCS | SHF_ALLOCB)) | sflags;
    180 	shf->errnosv = 0;
    181 	if (sflags & SHF_CLEXEC)
    182 		fcntl(fd, F_SETFD, FD_CLOEXEC);
    183 	return (shf);
    184 }
    185 
    186 /*
    187  * Open a string for reading or writing. If reading, bsize is the number
    188  * of bytes that can be read. If writing, bsize is the maximum number of
    189  * bytes that can be written. If shf is not NULL, it is filled in and
    190  * returned, if it is NULL, shf is allocated. If writing and buf is NULL
    191  * and SHF_DYNAMIC is set, the buffer is allocated (if bsize > 0, it is
    192  * used for the initial size). Doesn't fail.
    193  * When writing, a byte is reserved for a trailing NUL - see shf_sclose().
    194  */
    195 struct shf *
    196 shf_sopen(char *buf, ssize_t bsize, int sflags, struct shf *shf)
    197 {
    198 	/* can't have a read+write string */
    199 	if (!(!(sflags & SHF_RD) ^ !(sflags & SHF_WR)))
    200 		internal_errorf(Tf_flags, "shf_sopen",
    201 		    (unsigned int)sflags);
    202 
    203 	if (!shf) {
    204 		shf = alloc(sizeof(struct shf), ATEMP);
    205 		sflags |= SHF_ALLOCS;
    206 	}
    207 	shf->areap = ATEMP;
    208 	if (!buf && (sflags & SHF_WR) && (sflags & SHF_DYNAMIC)) {
    209 		if (bsize <= 0)
    210 			bsize = 64;
    211 		sflags |= SHF_ALLOCB;
    212 		buf = alloc(bsize, shf->areap);
    213 	}
    214 	shf->fd = -1;
    215 	shf->buf = shf->rp = shf->wp = (unsigned char *)buf;
    216 	shf->rnleft = bsize;
    217 	shf->rbsize = bsize;
    218 	shf->wnleft = bsize - 1;	/* space for a '\0' */
    219 	shf->wbsize = bsize;
    220 	shf->flags = sflags | SHF_STRING;
    221 	shf->errnosv = 0;
    222 	shf->bsize = bsize;
    223 
    224 	return (shf);
    225 }
    226 
    227 /* Flush and close file descriptor, free the shf structure */
    228 int
    229 shf_close(struct shf *shf)
    230 {
    231 	int ret = 0;
    232 
    233 	if (shf->fd >= 0) {
    234 		ret = shf_flush(shf);
    235 		if (close(shf->fd) < 0)
    236 			ret = -1;
    237 	}
    238 	if (shf->flags & SHF_ALLOCS)
    239 		afree(shf, shf->areap);
    240 	else if (shf->flags & SHF_ALLOCB)
    241 		afree(shf->buf, shf->areap);
    242 
    243 	return (ret);
    244 }
    245 
    246 /* Flush and close file descriptor, don't free file structure */
    247 int
    248 shf_fdclose(struct shf *shf)
    249 {
    250 	int ret = 0;
    251 
    252 	if (shf->fd >= 0) {
    253 		ret = shf_flush(shf);
    254 		if (close(shf->fd) < 0)
    255 			ret = -1;
    256 		shf->rnleft = 0;
    257 		shf->rp = shf->buf;
    258 		shf->wnleft = 0;
    259 		shf->fd = -1;
    260 	}
    261 
    262 	return (ret);
    263 }
    264 
    265 /*
    266  * Close a string - if it was opened for writing, it is NUL terminated;
    267  * returns a pointer to the string and frees shf if it was allocated
    268  * (does not free string if it was allocated).
    269  */
    270 char *
    271 shf_sclose(struct shf *shf)
    272 {
    273 	unsigned char *s = shf->buf;
    274 
    275 	/* NUL terminate */
    276 	if (shf->flags & SHF_WR) {
    277 		shf->wnleft++;
    278 		shf_putc('\0', shf);
    279 	}
    280 	if (shf->flags & SHF_ALLOCS)
    281 		afree(shf, shf->areap);
    282 	return ((char *)s);
    283 }
    284 
    285 /*
    286  * Un-read what has been read but not examined, or write what has been
    287  * buffered. Returns 0 for success, -1 for (write) error.
    288  */
    289 int
    290 shf_flush(struct shf *shf)
    291 {
    292 	int rv = 0;
    293 
    294 	if (shf->flags & SHF_STRING)
    295 		rv = (shf->flags & SHF_WR) ? -1 : 0;
    296 	else if (shf->fd < 0)
    297 		internal_errorf(Tf_sD_s, "shf_flush", "no fd");
    298 	else if (shf->flags & SHF_ERROR) {
    299 		errno = shf->errnosv;
    300 		rv = -1;
    301 	} else if (shf->flags & SHF_READING) {
    302 		shf->flags &= ~(SHF_EOF | SHF_READING);
    303 		if (shf->rnleft > 0) {
    304 			if (lseek(shf->fd, (off_t)-shf->rnleft,
    305 			    SEEK_CUR) == -1) {
    306 				shf->flags |= SHF_ERROR;
    307 				shf->errnosv = errno;
    308 				rv = -1;
    309 			}
    310 			shf->rnleft = 0;
    311 			shf->rp = shf->buf;
    312 		}
    313 	} else if (shf->flags & SHF_WRITING)
    314 		rv = shf_emptybuf(shf, 0);
    315 
    316 	return (rv);
    317 }
    318 
    319 /*
    320  * Write out any buffered data. If currently reading, flushes the read
    321  * buffer. Returns 0 for success, -1 for (write) error.
    322  */
    323 static int
    324 shf_emptybuf(struct shf *shf, int flags)
    325 {
    326 	int ret = 0;
    327 
    328 	if (!(shf->flags & SHF_STRING) && shf->fd < 0)
    329 		internal_errorf(Tf_sD_s, "shf_emptybuf", "no fd");
    330 
    331 	if (shf->flags & SHF_ERROR) {
    332 		errno = shf->errnosv;
    333 		return (-1);
    334 	}
    335 
    336 	if (shf->flags & SHF_READING) {
    337 		if (flags & EB_READSW)
    338 			/* doesn't happen */
    339 			return (0);
    340 		ret = shf_flush(shf);
    341 		shf->flags &= ~SHF_READING;
    342 	}
    343 	if (shf->flags & SHF_STRING) {
    344 		unsigned char *nbuf;
    345 
    346 		/*
    347 		 * Note that we assume SHF_ALLOCS is not set if
    348 		 * SHF_ALLOCB is set... (changing the shf pointer could
    349 		 * cause problems)
    350 		 */
    351 		if (!(flags & EB_GROW) || !(shf->flags & SHF_DYNAMIC) ||
    352 		    !(shf->flags & SHF_ALLOCB))
    353 			return (-1);
    354 		/* allocate more space for buffer */
    355 		nbuf = aresize2(shf->buf, 2, shf->wbsize, shf->areap);
    356 		shf->rp = nbuf + (shf->rp - shf->buf);
    357 		shf->wp = nbuf + (shf->wp - shf->buf);
    358 		shf->rbsize += shf->wbsize;
    359 		shf->wnleft += shf->wbsize;
    360 		shf->wbsize <<= 1;
    361 		shf->buf = nbuf;
    362 	} else {
    363 		if (shf->flags & SHF_WRITING) {
    364 			ssize_t n, ntowrite = shf->wp - shf->buf;
    365 			unsigned char *buf = shf->buf;
    366 
    367 			while (ntowrite > 0) {
    368 				n = write(shf->fd, buf, ntowrite);
    369 				if (n < 0) {
    370 					if (errno == EINTR &&
    371 					    !(shf->flags & SHF_INTERRUPT))
    372 						continue;
    373 					shf->flags |= SHF_ERROR;
    374 					shf->errnosv = errno;
    375 					shf->wnleft = 0;
    376 					if (buf != shf->buf) {
    377 						/*
    378 						 * allow a second flush
    379 						 * to work
    380 						 */
    381 						memmove(shf->buf, buf,
    382 						    ntowrite);
    383 						shf->wp = shf->buf + ntowrite;
    384 					}
    385 					return (-1);
    386 				}
    387 				buf += n;
    388 				ntowrite -= n;
    389 			}
    390 			if (flags & EB_READSW) {
    391 				shf->wp = shf->buf;
    392 				shf->wnleft = 0;
    393 				shf->flags &= ~SHF_WRITING;
    394 				return (0);
    395 			}
    396 		}
    397 		shf->wp = shf->buf;
    398 		shf->wnleft = shf->wbsize;
    399 	}
    400 	shf->flags |= SHF_WRITING;
    401 
    402 	return (ret);
    403 }
    404 
    405 /* Fill up a read buffer. Returns -1 for a read error, 0 otherwise. */
    406 static int
    407 shf_fillbuf(struct shf *shf)
    408 {
    409 	ssize_t n;
    410 
    411 	if (shf->flags & SHF_STRING)
    412 		return (0);
    413 
    414 	if (shf->fd < 0)
    415 		internal_errorf(Tf_sD_s, "shf_fillbuf", "no fd");
    416 
    417 	if (shf->flags & (SHF_EOF | SHF_ERROR)) {
    418 		if (shf->flags & SHF_ERROR)
    419 			errno = shf->errnosv;
    420 		return (-1);
    421 	}
    422 
    423 	if ((shf->flags & SHF_WRITING) && shf_emptybuf(shf, EB_READSW) == -1)
    424 		return (-1);
    425 
    426 	shf->flags |= SHF_READING;
    427 
    428 	shf->rp = shf->buf;
    429 	while (/* CONSTCOND */ 1) {
    430 		n = blocking_read(shf->fd, (char *)shf->buf, shf->rbsize);
    431 		if (n < 0 && errno == EINTR && !(shf->flags & SHF_INTERRUPT))
    432 			continue;
    433 		break;
    434 	}
    435 	if (n < 0) {
    436 		shf->flags |= SHF_ERROR;
    437 		shf->errnosv = errno;
    438 		shf->rnleft = 0;
    439 		shf->rp = shf->buf;
    440 		return (-1);
    441 	}
    442 	if ((shf->rnleft = n) == 0)
    443 		shf->flags |= SHF_EOF;
    444 	return (0);
    445 }
    446 
    447 /*
    448  * Read a buffer from shf. Returns the number of bytes read into buf, if
    449  * no bytes were read, returns 0 if end of file was seen, -1 if a read
    450  * error occurred.
    451  */
    452 ssize_t
    453 shf_read(char *buf, ssize_t bsize, struct shf *shf)
    454 {
    455 	ssize_t ncopy, orig_bsize = bsize;
    456 
    457 	if (!(shf->flags & SHF_RD))
    458 		internal_errorf(Tf_flags, Tshf_read,
    459 		    (unsigned int)shf->flags);
    460 
    461 	if (bsize <= 0)
    462 		internal_errorf(Tf_szs, Tshf_read, bsize, Tbsize);
    463 
    464 	while (bsize > 0) {
    465 		if (shf->rnleft == 0 &&
    466 		    (shf_fillbuf(shf) == -1 || shf->rnleft == 0))
    467 			break;
    468 		ncopy = shf->rnleft;
    469 		if (ncopy > bsize)
    470 			ncopy = bsize;
    471 		memcpy(buf, shf->rp, ncopy);
    472 		buf += ncopy;
    473 		bsize -= ncopy;
    474 		shf->rp += ncopy;
    475 		shf->rnleft -= ncopy;
    476 	}
    477 	/* Note: fread(3S) returns 0 for errors - this doesn't */
    478 	return (orig_bsize == bsize ? (shf_error(shf) ? -1 : 0) :
    479 	    orig_bsize - bsize);
    480 }
    481 
    482 /*
    483  * Read up to a newline or -1. The newline is put in buf; buf is always
    484  * NUL terminated. Returns NULL on read error or if nothing was read
    485  * before end of file, returns a pointer to the NUL byte in buf
    486  * otherwise.
    487  */
    488 char *
    489 shf_getse(char *buf, ssize_t bsize, struct shf *shf)
    490 {
    491 	unsigned char *end;
    492 	ssize_t ncopy;
    493 	char *orig_buf = buf;
    494 
    495 	if (!(shf->flags & SHF_RD))
    496 		internal_errorf(Tf_flags, "shf_getse",
    497 		    (unsigned int)shf->flags);
    498 
    499 	if (bsize <= 0)
    500 		return (NULL);
    501 
    502 	/* save room for NUL */
    503 	--bsize;
    504 	do {
    505 		if (shf->rnleft == 0) {
    506 			if (shf_fillbuf(shf) == -1)
    507 				return (NULL);
    508 			if (shf->rnleft == 0) {
    509 				*buf = '\0';
    510 				return (buf == orig_buf ? NULL : buf);
    511 			}
    512 		}
    513 		end = (unsigned char *)memchr((char *)shf->rp, '\n',
    514 		    shf->rnleft);
    515 		ncopy = end ? end - shf->rp + 1 : shf->rnleft;
    516 		if (ncopy > bsize)
    517 			ncopy = bsize;
    518 		memcpy(buf, (char *) shf->rp, ncopy);
    519 		shf->rp += ncopy;
    520 		shf->rnleft -= ncopy;
    521 		buf += ncopy;
    522 		bsize -= ncopy;
    523 #ifdef MKSH_WITH_TEXTMODE
    524 		if (end && buf > orig_buf + 1 && buf[-2] == '\r') {
    525 			buf--;
    526 			bsize++;
    527 			buf[-1] = '\n';
    528 		}
    529 #endif
    530 	} while (!end && bsize);
    531 #ifdef MKSH_WITH_TEXTMODE
    532 	if (!bsize && buf[-1] == '\r') {
    533 		int c = shf_getc(shf);
    534 		if (c == '\n')
    535 			buf[-1] = '\n';
    536 		else if (c != -1)
    537 			shf_ungetc(c, shf);
    538 	}
    539 #endif
    540 	*buf = '\0';
    541 	return (buf);
    542 }
    543 
    544 /* Returns the char read. Returns -1 for error and end of file. */
    545 int
    546 shf_getchar(struct shf *shf)
    547 {
    548 	if (!(shf->flags & SHF_RD))
    549 		internal_errorf(Tf_flags, "shf_getchar",
    550 		    (unsigned int)shf->flags);
    551 
    552 	if (shf->rnleft == 0 && (shf_fillbuf(shf) == -1 || shf->rnleft == 0))
    553 		return (-1);
    554 	--shf->rnleft;
    555 	return (*shf->rp++);
    556 }
    557 
    558 /*
    559  * Put a character back in the input stream. Returns the character if
    560  * successful, -1 if there is no room.
    561  */
    562 int
    563 shf_ungetc(int c, struct shf *shf)
    564 {
    565 	if (!(shf->flags & SHF_RD))
    566 		internal_errorf(Tf_flags, "shf_ungetc",
    567 		    (unsigned int)shf->flags);
    568 
    569 	if ((shf->flags & SHF_ERROR) || c == -1 ||
    570 	    (shf->rp == shf->buf && shf->rnleft))
    571 		return (-1);
    572 
    573 	if ((shf->flags & SHF_WRITING) && shf_emptybuf(shf, EB_READSW) == -1)
    574 		return (-1);
    575 
    576 	if (shf->rp == shf->buf)
    577 		shf->rp = shf->buf + shf->rbsize;
    578 	if (shf->flags & SHF_STRING) {
    579 		/*
    580 		 * Can unget what was read, but not something different;
    581 		 * we don't want to modify a string.
    582 		 */
    583 		if ((int)(shf->rp[-1]) != c)
    584 			return (-1);
    585 		shf->flags &= ~SHF_EOF;
    586 		shf->rp--;
    587 		shf->rnleft++;
    588 		return (c);
    589 	}
    590 	shf->flags &= ~SHF_EOF;
    591 	*--(shf->rp) = c;
    592 	shf->rnleft++;
    593 	return (c);
    594 }
    595 
    596 /*
    597  * Write a character. Returns the character if successful, -1 if the
    598  * char could not be written.
    599  */
    600 int
    601 shf_putchar(int c, struct shf *shf)
    602 {
    603 	if (!(shf->flags & SHF_WR))
    604 		internal_errorf(Tf_flags, "shf_putchar",
    605 		    (unsigned int)shf->flags);
    606 
    607 	if (c == -1)
    608 		return (-1);
    609 
    610 	if (shf->flags & SHF_UNBUF) {
    611 		unsigned char cc = (unsigned char)c;
    612 		ssize_t n;
    613 
    614 		if (shf->fd < 0)
    615 			internal_errorf(Tf_sD_s, "shf_putchar", "no fd");
    616 		if (shf->flags & SHF_ERROR) {
    617 			errno = shf->errnosv;
    618 			return (-1);
    619 		}
    620 		while ((n = write(shf->fd, &cc, 1)) != 1)
    621 			if (n < 0) {
    622 				if (errno == EINTR &&
    623 				    !(shf->flags & SHF_INTERRUPT))
    624 					continue;
    625 				shf->flags |= SHF_ERROR;
    626 				shf->errnosv = errno;
    627 				return (-1);
    628 			}
    629 	} else {
    630 		/* Flush deals with strings and sticky errors */
    631 		if (shf->wnleft == 0 && shf_emptybuf(shf, EB_GROW) == -1)
    632 			return (-1);
    633 		shf->wnleft--;
    634 		*shf->wp++ = c;
    635 	}
    636 
    637 	return (c);
    638 }
    639 
    640 /*
    641  * Write a string. Returns the length of the string if successful, -1
    642  * if the string could not be written.
    643  */
    644 ssize_t
    645 shf_puts(const char *s, struct shf *shf)
    646 {
    647 	if (!s)
    648 		return (-1);
    649 
    650 	return (shf_write(s, strlen(s), shf));
    651 }
    652 
    653 /* Write a buffer. Returns nbytes if successful, -1 if there is an error. */
    654 ssize_t
    655 shf_write(const char *buf, ssize_t nbytes, struct shf *shf)
    656 {
    657 	ssize_t n, ncopy, orig_nbytes = nbytes;
    658 
    659 	if (!(shf->flags & SHF_WR))
    660 		internal_errorf(Tf_flags, Tshf_write,
    661 		    (unsigned int)shf->flags);
    662 
    663 	if (nbytes < 0)
    664 		internal_errorf(Tf_szs, Tshf_write, nbytes, Tbytes);
    665 
    666 	/* Don't buffer if buffer is empty and we're writting a large amount. */
    667 	if ((ncopy = shf->wnleft) &&
    668 	    (shf->wp != shf->buf || nbytes < shf->wnleft)) {
    669 		if (ncopy > nbytes)
    670 			ncopy = nbytes;
    671 		memcpy(shf->wp, buf, ncopy);
    672 		nbytes -= ncopy;
    673 		buf += ncopy;
    674 		shf->wp += ncopy;
    675 		shf->wnleft -= ncopy;
    676 	}
    677 	if (nbytes > 0) {
    678 		if (shf->flags & SHF_STRING) {
    679 			/* resize buffer until there's enough space left */
    680 			while (nbytes > shf->wnleft)
    681 				if (shf_emptybuf(shf, EB_GROW) == -1)
    682 					return (-1);
    683 			/* then write everything into the buffer */
    684 		} else {
    685 			/* flush deals with sticky errors */
    686 			if (shf_emptybuf(shf, EB_GROW) == -1)
    687 				return (-1);
    688 			/* write chunks larger than window size directly */
    689 			if (nbytes > shf->wbsize) {
    690 				ncopy = nbytes;
    691 				if (shf->wbsize)
    692 					ncopy -= nbytes % shf->wbsize;
    693 				nbytes -= ncopy;
    694 				while (ncopy > 0) {
    695 					n = write(shf->fd, buf, ncopy);
    696 					if (n < 0) {
    697 						if (errno == EINTR &&
    698 						    !(shf->flags & SHF_INTERRUPT))
    699 							continue;
    700 						shf->flags |= SHF_ERROR;
    701 						shf->errnosv = errno;
    702 						shf->wnleft = 0;
    703 						/*
    704 						 * Note: fwrite(3) returns 0
    705 						 * for errors - this doesn't
    706 						 */
    707 						return (-1);
    708 					}
    709 					buf += n;
    710 					ncopy -= n;
    711 				}
    712 			}
    713 			/* ... and buffer the rest */
    714 		}
    715 		if (nbytes > 0) {
    716 			/* write remaining bytes to buffer */
    717 			memcpy(shf->wp, buf, nbytes);
    718 			shf->wp += nbytes;
    719 			shf->wnleft -= nbytes;
    720 		}
    721 	}
    722 
    723 	return (orig_nbytes);
    724 }
    725 
    726 ssize_t
    727 shf_fprintf(struct shf *shf, const char *fmt, ...)
    728 {
    729 	va_list args;
    730 	ssize_t n;
    731 
    732 	va_start(args, fmt);
    733 	n = shf_vfprintf(shf, fmt, args);
    734 	va_end(args);
    735 
    736 	return (n);
    737 }
    738 
    739 ssize_t
    740 shf_snprintf(char *buf, ssize_t bsize, const char *fmt, ...)
    741 {
    742 	struct shf shf;
    743 	va_list args;
    744 	ssize_t n;
    745 
    746 	if (!buf || bsize <= 0)
    747 		internal_errorf("shf_snprintf: buf %zX, bsize %zd",
    748 		    (size_t)buf, bsize);
    749 
    750 	shf_sopen(buf, bsize, SHF_WR, &shf);
    751 	va_start(args, fmt);
    752 	n = shf_vfprintf(&shf, fmt, args);
    753 	va_end(args);
    754 	/* NUL terminates */
    755 	shf_sclose(&shf);
    756 	return (n);
    757 }
    758 
    759 char *
    760 shf_smprintf(const char *fmt, ...)
    761 {
    762 	struct shf shf;
    763 	va_list args;
    764 
    765 	shf_sopen(NULL, 0, SHF_WR|SHF_DYNAMIC, &shf);
    766 	va_start(args, fmt);
    767 	shf_vfprintf(&shf, fmt, args);
    768 	va_end(args);
    769 	/* NUL terminates */
    770 	return (shf_sclose(&shf));
    771 }
    772 
    773 #define	FL_HASH		0x001	/* '#' seen */
    774 #define FL_PLUS		0x002	/* '+' seen */
    775 #define FL_RIGHT	0x004	/* '-' seen */
    776 #define FL_BLANK	0x008	/* ' ' seen */
    777 #define FL_SHORT	0x010	/* 'h' seen */
    778 #define FL_LONG		0x020	/* 'l' seen */
    779 #define FL_ZERO		0x040	/* '0' seen */
    780 #define FL_DOT		0x080	/* '.' seen */
    781 #define FL_UPPER	0x100	/* format character was uppercase */
    782 #define FL_NUMBER	0x200	/* a number was formated %[douxefg] */
    783 #define FL_SIZET	0x400	/* 'z' seen */
    784 #define FM_SIZES	0x430	/* h/l/z mask */
    785 
    786 ssize_t
    787 shf_vfprintf(struct shf *shf, const char *fmt, va_list args)
    788 {
    789 	const char *s;
    790 	char c, *cp;
    791 	int tmp = 0, flags;
    792 	size_t field, precision, len;
    793 	unsigned long lnum;
    794 	/* %#o produces the longest output */
    795 	char numbuf[(8 * sizeof(long) + 2) / 3 + 1 + /* NUL */ 1];
    796 	/* this stuff for dealing with the buffer */
    797 	ssize_t nwritten = 0;
    798 
    799 #define VA(type) va_arg(args, type)
    800 
    801 	if (!fmt)
    802 		return (0);
    803 
    804 	while ((c = *fmt++)) {
    805 		if (c != '%') {
    806 			shf_putc(c, shf);
    807 			nwritten++;
    808 			continue;
    809 		}
    810 		/*
    811 		 * This will accept flags/fields in any order - not just
    812 		 * the order specified in printf(3), but this is the way
    813 		 * _doprnt() seems to work (on BSD and SYSV). The only
    814 		 * restriction is that the format character must come
    815 		 * last :-).
    816 		 */
    817 		flags = 0;
    818 		field = precision = 0;
    819 		while ((c = *fmt++)) {
    820 			switch (c) {
    821 			case '#':
    822 				flags |= FL_HASH;
    823 				continue;
    824 
    825 			case '+':
    826 				flags |= FL_PLUS;
    827 				continue;
    828 
    829 			case '-':
    830 				flags |= FL_RIGHT;
    831 				continue;
    832 
    833 			case ' ':
    834 				flags |= FL_BLANK;
    835 				continue;
    836 
    837 			case '0':
    838 				if (!(flags & FL_DOT))
    839 					flags |= FL_ZERO;
    840 				continue;
    841 
    842 			case '.':
    843 				flags |= FL_DOT;
    844 				precision = 0;
    845 				continue;
    846 
    847 			case '*':
    848 				tmp = VA(int);
    849 				if (tmp < 0) {
    850 					if (flags & FL_DOT)
    851 						precision = 0;
    852 					else {
    853 						field = (unsigned int)-tmp;
    854 						flags |= FL_RIGHT;
    855 					}
    856 				} else if (flags & FL_DOT)
    857 					precision = (unsigned int)tmp;
    858 				else
    859 					field = (unsigned int)tmp;
    860 				continue;
    861 
    862 			case 'l':
    863 				flags &= ~FM_SIZES;
    864 				flags |= FL_LONG;
    865 				continue;
    866 
    867 			case 'h':
    868 				flags &= ~FM_SIZES;
    869 				flags |= FL_SHORT;
    870 				continue;
    871 
    872 			case 'z':
    873 				flags &= ~FM_SIZES;
    874 				flags |= FL_SIZET;
    875 				continue;
    876 			}
    877 			if (ksh_isdigit(c)) {
    878 				bool overflowed = false;
    879 
    880 				tmp = ksh_numdig(c);
    881 				while (c = *fmt++, ksh_isdigit(c))
    882 					if (notok2mul(2147483647, tmp, 10))
    883 						overflowed = true;
    884 					else
    885 						tmp = tmp * 10 + ksh_numdig(c);
    886 				--fmt;
    887 				if (overflowed)
    888 					tmp = 0;
    889 				if (flags & FL_DOT)
    890 					precision = (unsigned int)tmp;
    891 				else
    892 					field = (unsigned int)tmp;
    893 				continue;
    894 			}
    895 			break;
    896 		}
    897 
    898 		if (!c)
    899 			/* nasty format */
    900 			break;
    901 
    902 		if (ksh_isupper(c)) {
    903 			flags |= FL_UPPER;
    904 			c = ksh_tolower(c);
    905 		}
    906 
    907 		switch (c) {
    908 		case 'd':
    909 		case 'i':
    910 			if (flags & FL_SIZET)
    911 				lnum = (long)VA(ssize_t);
    912 			else if (flags & FL_LONG)
    913 				lnum = VA(long);
    914 			else if (flags & FL_SHORT)
    915 				lnum = (long)(short)VA(int);
    916 			else
    917 				lnum = (long)VA(int);
    918 			goto integral;
    919 
    920 		case 'o':
    921 		case 'u':
    922 		case 'x':
    923 			if (flags & FL_SIZET)
    924 				lnum = VA(size_t);
    925 			else if (flags & FL_LONG)
    926 				lnum = VA(unsigned long);
    927 			else if (flags & FL_SHORT)
    928 				lnum = (unsigned long)(unsigned short)VA(int);
    929 			else
    930 				lnum = (unsigned long)VA(unsigned int);
    931 
    932  integral:
    933 			flags |= FL_NUMBER;
    934 			cp = numbuf + sizeof(numbuf);
    935 			*--cp = '\0';
    936 
    937 			switch (c) {
    938 			case 'd':
    939 			case 'i':
    940 				if (0 > (long)lnum) {
    941 					lnum = -(long)lnum;
    942 					tmp = 1;
    943 				} else
    944 					tmp = 0;
    945 				/* FALLTHROUGH */
    946 			case 'u':
    947 				do {
    948 					*--cp = digits_lc[lnum % 10];
    949 					lnum /= 10;
    950 				} while (lnum);
    951 
    952 				if (c != 'u') {
    953 					if (tmp)
    954 						*--cp = '-';
    955 					else if (flags & FL_PLUS)
    956 						*--cp = '+';
    957 					else if (flags & FL_BLANK)
    958 						*--cp = ' ';
    959 				}
    960 				break;
    961 
    962 			case 'o':
    963 				do {
    964 					*--cp = digits_lc[lnum & 0x7];
    965 					lnum >>= 3;
    966 				} while (lnum);
    967 
    968 				if ((flags & FL_HASH) && *cp != '0')
    969 					*--cp = '0';
    970 				break;
    971 
    972 			case 'x': {
    973 				const char *digits = (flags & FL_UPPER) ?
    974 				    digits_uc : digits_lc;
    975 				do {
    976 					*--cp = digits[lnum & 0xF];
    977 					lnum >>= 4;
    978 				} while (lnum);
    979 
    980 				if (flags & FL_HASH) {
    981 					*--cp = (flags & FL_UPPER) ? 'X' : 'x';
    982 					*--cp = '0';
    983 				}
    984 			    }
    985 			}
    986 			len = numbuf + sizeof(numbuf) - 1 - (s = cp);
    987 			if (flags & FL_DOT) {
    988 				if (precision > len) {
    989 					field = precision;
    990 					flags |= FL_ZERO;
    991 				} else
    992 					/* no loss */
    993 					precision = len;
    994 			}
    995 			break;
    996 
    997 		case 's':
    998 			if ((s = VA(const char *)) == NULL)
    999 				s = "(null)";
   1000 			else if (flags & FL_HASH) {
   1001 				print_value_quoted(shf, s);
   1002 				continue;
   1003 			}
   1004 			len = utf_mbswidth(s);
   1005 			break;
   1006 
   1007 		case 'c':
   1008 			flags &= ~FL_DOT;
   1009 			c = (char)(VA(int));
   1010 			/* FALLTHROUGH */
   1011 
   1012 		case '%':
   1013 		default:
   1014 			numbuf[0] = c;
   1015 			numbuf[1] = 0;
   1016 			s = numbuf;
   1017 			len = 1;
   1018 			break;
   1019 		}
   1020 
   1021 		/*
   1022 		 * At this point s should point to a string that is to be
   1023 		 * formatted, and len should be the length of the string.
   1024 		 */
   1025 		if (!(flags & FL_DOT) || len < precision)
   1026 			precision = len;
   1027 		if (field > precision) {
   1028 			field -= precision;
   1029 			if (!(flags & FL_RIGHT)) {
   1030 				/* skip past sign or 0x when padding with 0 */
   1031 				if ((flags & FL_ZERO) && (flags & FL_NUMBER)) {
   1032 					if (*s == '+' || *s == '-' ||
   1033 					    *s == ' ') {
   1034 						shf_putc(*s, shf);
   1035 						s++;
   1036 						precision--;
   1037 						nwritten++;
   1038 					} else if (*s == '0') {
   1039 						shf_putc(*s, shf);
   1040 						s++;
   1041 						nwritten++;
   1042 						if (--precision &&
   1043 						    ksh_eq(*s, 'X', 'x')) {
   1044 							shf_putc(*s, shf);
   1045 							s++;
   1046 							precision--;
   1047 							nwritten++;
   1048 						}
   1049 					}
   1050 					c = '0';
   1051 				} else
   1052 					c = flags & FL_ZERO ? '0' : ' ';
   1053 				nwritten += field;
   1054 				while (field--)
   1055 					shf_putc(c, shf);
   1056 				field = 0;
   1057 			} else
   1058 				c = ' ';
   1059 		} else
   1060 			field = 0;
   1061 
   1062 		nwritten += precision;
   1063 		precision = utf_skipcols(s, precision, &tmp) - s;
   1064 		while (precision--)
   1065 			shf_putc(*s++, shf);
   1066 
   1067 		nwritten += field;
   1068 		while (field--)
   1069 			shf_putc(c, shf);
   1070 	}
   1071 
   1072 	return (shf_error(shf) ? -1 : nwritten);
   1073 }
   1074 
   1075 #if defined(MKSH_SMALL) && !defined(MKSH_SMALL_BUT_FAST)
   1076 int
   1077 shf_getc(struct shf *shf)
   1078 {
   1079 	return (shf_getc_i(shf));
   1080 }
   1081 
   1082 int
   1083 shf_putc(int c, struct shf *shf)
   1084 {
   1085 	return (shf_putc_i(c, shf));
   1086 }
   1087 #endif
   1088 
   1089 #ifdef DEBUG
   1090 const char *
   1091 cstrerror(int errnum)
   1092 {
   1093 #undef strerror
   1094 	return (strerror(errnum));
   1095 #define strerror dontuse_strerror /* poisoned */
   1096 }
   1097 #elif !HAVE_STRERROR
   1098 
   1099 #if HAVE_SYS_ERRLIST
   1100 #if !HAVE_SYS_ERRLIST_DECL
   1101 extern const int sys_nerr;
   1102 extern const char * const sys_errlist[];
   1103 #endif
   1104 #endif
   1105 
   1106 const char *
   1107 cstrerror(int errnum)
   1108 {
   1109 	/* "Unknown error: " + sign + rough estimate + NUL */
   1110 	static char errbuf[15 + 1 + (8 * sizeof(int) + 2) / 3 + 1];
   1111 
   1112 #if HAVE_SYS_ERRLIST
   1113 	if (errnum > 0 && errnum < sys_nerr && sys_errlist[errnum])
   1114 		return (sys_errlist[errnum]);
   1115 #endif
   1116 
   1117 	switch (errnum) {
   1118 	case 0:
   1119 		return ("Undefined error: 0");
   1120 	case EPERM:
   1121 		return ("Operation not permitted");
   1122 	case ENOENT:
   1123 		return ("No such file or directory");
   1124 #ifdef ESRCH
   1125 	case ESRCH:
   1126 		return ("No such process");
   1127 #endif
   1128 #ifdef E2BIG
   1129 	case E2BIG:
   1130 		return ("Argument list too long");
   1131 #endif
   1132 	case ENOEXEC:
   1133 		return ("Exec format error");
   1134 	case EBADF:
   1135 		return ("Bad file descriptor");
   1136 #ifdef ENOMEM
   1137 	case ENOMEM:
   1138 		return ("Cannot allocate memory");
   1139 #endif
   1140 	case EACCES:
   1141 		return ("Permission denied");
   1142 	case EEXIST:
   1143 		return ("File exists");
   1144 	case ENOTDIR:
   1145 		return ("Not a directory");
   1146 #ifdef EINVAL
   1147 	case EINVAL:
   1148 		return ("Invalid argument");
   1149 #endif
   1150 #ifdef ELOOP
   1151 	case ELOOP:
   1152 		return ("Too many levels of symbolic links");
   1153 #endif
   1154 	default:
   1155 		shf_snprintf(errbuf, sizeof(errbuf),
   1156 		    "Unknown error: %d", errnum);
   1157 		return (errbuf);
   1158 	}
   1159 }
   1160 #endif
   1161