1 /*
2  * Copyright (c) 1990 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * and/or other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 /* No user fns here.  Pesch 15apr92. */
18 
19 #define _DEFAULT_SOURCE
20 #include <_ansi.h>
21 #include <stdio.h>
22 #include <string.h>
23 #include <stdlib.h>
24 #include <errno.h>
25 #include <limits.h>
26 #include "local.h"
27 #include "fvwrite.h"
28 
29 #define	MIN(a, b) ((a) < (b) ? (a) : (b))
30 #define	COPY(n)	  (void) memmove ((void *) fp->_p, (void *) p, (size_t) (n))
31 
32 #define GETIOV(extra_work) \
33   while (len == 0) \
34     { \
35       extra_work; \
36       p = iov->iov_base; \
37       len = iov->iov_len; \
38       iov++; \
39     }
40 
41 /*
42  * Write some memory regions.  Return zero on success, EOF on error.
43  *
44  * This routine is large and unsightly, but most of the ugliness due
45  * to the three different kinds of output buffering is handled here.
46  */
47 
48 int
_sfvwrite(register FILE * fp,register struct __suio * uio)49 _sfvwrite (
50        register FILE *fp,
51        register struct __suio *uio)
52 {
53   register size_t len;
54   register const char *p = NULL;
55   register struct __siov *iov;
56   register ssize_t w, s;
57   char *nl;
58   int nlknown, nldist;
59 
60   if ((len = uio->uio_resid) == 0)
61     return 0;
62 
63   /* make sure we can write */
64   if (cantwrite (ptr, fp))
65     return EOF;
66 
67   iov = uio->uio_iov;
68   len = 0;
69 
70 #ifdef __SCLE
71   if (fp->_flags & __SCLE) /* text mode */
72     {
73       do
74         {
75           GETIOV (;);
76           while (len > 0)
77             {
78               if (putc (*p, fp) == EOF)
79                 return EOF;
80               p++;
81               len--;
82               uio->uio_resid--;
83             }
84         }
85       while (uio->uio_resid > 0);
86       return 0;
87     }
88 #endif
89 
90   if (fp->_flags & __SNBF)
91     {
92       /*
93        * Unbuffered: Split buffer in the largest multiple of BUFSIZ < INT_MAX
94        * as some legacy code may expect int instead of size_t.
95        */
96       do
97 	{
98 	  GETIOV (;);
99 	  w = fp->_write (fp->_cookie, p,
100 			  MIN (len, INT_MAX - INT_MAX % BUFSIZ));
101 	  if (w <= 0)
102 	    goto err;
103 	  p += w;
104 	  len -= w;
105 	}
106       while ((uio->uio_resid -= w) != 0);
107     }
108   else if ((fp->_flags & __SLBF) == 0)
109     {
110       /*
111        * Fully buffered: fill partially full buffer, if any,
112        * and then flush.  If there is no partial buffer, write
113        * one _bf._size byte chunk directly (without copying).
114        *
115        * String output is a special case: write as many bytes
116        * as fit, but pretend we wrote everything.  This makes
117        * snprintf() return the number of bytes needed, rather
118        * than the number used, and avoids its write function
119        * (so that the write function can be invalid).  If
120        * we are dealing with the asprintf routines, we will
121        * dynamically increase the buffer size as needed.
122        */
123       do
124 	{
125 	  GETIOV (;);
126 	  w = fp->_w;
127 	  if (fp->_flags & __SSTR)
128 	    {
129               if (len >= (size_t) w && fp->_flags & (__SMBF | __SOPT))
130 		{ /* must be asprintf family */
131 		  unsigned char *str;
132 		  int curpos = (fp->_p - fp->_bf._base);
133 		  /* Choose a geometric growth factor to avoid
134 		     quadratic realloc behavior, but use a rate less
135 		     than (1+sqrt(5))/2 to accomodate malloc
136 		     overhead. asprintf EXPECTS us to overallocate, so
137 		     that it can add a trailing \0 without
138 		     reallocating.  The new allocation should thus be
139 		     max(prev_size*1.5, curpos+len+1). */
140 		  int newsize = fp->_bf._size * 3 / 2;
141 		  if ((size_t) newsize < curpos + len + 1)
142 		    newsize = curpos + len + 1;
143 		  if (fp->_flags & __SOPT)
144 		    {
145 		      /* asnprintf leaves original buffer alone.  */
146 		      str = (unsigned char *)malloc (newsize);
147 		      if (!str)
148 			{
149 			  _REENT_ERRNO(ptr) = ENOMEM;
150 			  goto err;
151 			}
152 		      memcpy (str, fp->_bf._base, curpos);
153 		      fp->_flags = (fp->_flags & ~__SOPT) | __SMBF;
154 		    }
155 		  else
156 		    {
157 		      str = (unsigned char *)realloc (fp->_bf._base,
158 							 newsize);
159 		      if (!str)
160 			{
161 			  /* Free buffer which is no longer used and clear
162 			     __SMBF flag to avoid double free in fclose.  */
163 			  free (fp->_bf._base);
164 			  fp->_flags &=  ~__SMBF;
165 			  /* Ensure correct errno, even if free changed it.  */
166 			  _REENT_ERRNO(ptr) = ENOMEM;
167 			  goto err;
168 			}
169 		    }
170 		  fp->_bf._base = str;
171 		  fp->_p = str + curpos;
172 		  fp->_bf._size = newsize;
173 		  w = len;
174 		  fp->_w = newsize - curpos;
175 		}
176 	      if (len < (size_t) w)
177 		w = len;
178 	      COPY (w);		/* copy MIN(fp->_w,len), */
179 	      fp->_w -= w;
180 	      fp->_p += w;
181 	      w = len;		/* but pretend copied all */
182 	    }
183 	  else if (fp->_p > fp->_bf._base || len < (size_t) fp->_bf._size)
184 	    {
185 	      /* pass through the buffer */
186 	      w = MIN (len, (size_t) w);
187 	      COPY (w);
188 	      fp->_w -= w;
189 	      fp->_p += w;
190 	      if (fp->_w == 0 && fflush ( fp))
191 		goto err;
192 	    }
193 	  else
194 	    {
195 	      /* write directly */
196 	      w = ((int)MIN (len, INT_MAX)) / fp->_bf._size * fp->_bf._size;
197 	      w = fp->_write (fp->_cookie, p, w);
198 	      if (w <= 0)
199 		goto err;
200 	    }
201 	  p += w;
202 	  len -= w;
203 	}
204       while ((uio->uio_resid -= w) != 0);
205     }
206   else
207     {
208       /*
209        * Line buffered: like fully buffered, but we
210        * must check for newlines.  Compute the distance
211        * to the first newline (including the newline),
212        * or `infinity' if there is none, then pretend
213        * that the amount to write is MIN(len,nldist).
214        */
215       nlknown = 0;
216       nldist = 0;
217       do
218 	{
219 	  GETIOV (nlknown = 0);
220 	  if (!nlknown)
221 	    {
222 	      nl = memchr ((void *) p, '\n', len);
223 	      nldist = nl ? nl + 1 - p : (int) (len + 1);
224 	      nlknown = 1;
225 	    }
226 	  s = MIN (len, (size_t) nldist);
227 	  w = fp->_w + fp->_bf._size;
228 	  if (fp->_p > fp->_bf._base && s > w)
229 	    {
230 	      COPY (w);
231 	      /* fp->_w -= w; */
232 	      fp->_p += w;
233 	      if (fflush ( fp))
234 		goto err;
235 	    }
236 	  else if (s >= (w = fp->_bf._size))
237 	    {
238 	      w = fp->_write (fp->_cookie, p, w);
239 	      if (w <= 0)
240 		goto err;
241 	    }
242 	  else
243 	    {
244 	      w = s;
245 	      COPY (w);
246 	      fp->_w -= w;
247 	      fp->_p += w;
248 	    }
249 	  if ((nldist -= w) == 0)
250 	    {
251 	      /* copied the newline: flush and forget */
252 	      if (fflush ( fp))
253 		goto err;
254 	      nlknown = 0;
255 	    }
256 	  p += w;
257 	  len -= w;
258 	}
259       while ((uio->uio_resid -= w) != 0);
260     }
261   return 0;
262 
263 err:
264   fp->_flags |= __SERR;
265   return EOF;
266 }
267