1 /*
2 * Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
3 * All rights reserved.
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * By using this file, you agree to the terms and conditions set
11 * forth in the LICENSE file which can be found at the top level of
12 * the sendmail distribution.
13 */
14
15 #pragma ident "%Z%%M% %I% %E% SMI"
16
17 #include <sm/gen.h>
18 SM_RCSID("@(#)$Id: makebuf.c,v 1.26 2001/10/31 16:04:08 ca Exp $")
19 #include <stdlib.h>
20 #include <unistd.h>
21 #include <sys/types.h>
22 #include <sys/stat.h>
23 #include <sm/io.h>
24 #include <sm/heap.h>
25 #include <sm/conf.h>
26 #include "local.h"
27
28 /*
29 ** SM_MAKEBUF -- make a buffer for the file
30 **
31 ** Parameters:
32 ** fp -- the file to be buffered
33 **
34 ** Returns:
35 ** nothing
36 **
37 ** Allocate a file buffer, or switch to unbuffered I/O.
38 ** By default tty devices default to line buffered.
39 */
40
41 void
42 sm_makebuf(fp)
43 register SM_FILE_T *fp;
44 {
45 register void *p;
46 register int flags;
47 size_t size;
48 int couldbetty;
49
50 if (fp->f_flags & SMNBF)
51 {
52 fp->f_bf.smb_base = fp->f_p = fp->f_nbuf;
53 fp->f_bf.smb_size = 1;
54 return;
55 }
56 flags = sm_whatbuf(fp, &size, &couldbetty);
57 if ((p = sm_malloc(size)) == NULL)
58 {
59 fp->f_flags |= SMNBF;
60 fp->f_bf.smb_base = fp->f_p = fp->f_nbuf;
61 fp->f_bf.smb_size = 1;
62 return;
63 }
64 if (!Sm_IO_DidInit)
65 sm_init();
66 flags |= SMMBF;
67 fp->f_bf.smb_base = fp->f_p = p;
68 fp->f_bf.smb_size = size;
69 if (couldbetty && isatty(fp->f_file))
70 flags |= SMLBF;
71 fp->f_flags |= flags;
72 }
73
74 /*
75 ** SM_WHATBUF -- determine proper buffer for a file (internal)
76 **
77 ** Plus it fills in 'bufsize' for recommended buffer size and
78 ** fills in flag to indicate if 'fp' could be a tty (nothing
79 ** to do with "betty" :-) ).
80 **
81 ** Parameters:
82 ** fp -- file pointer to be buffered
83 ** bufsize -- new buffer size (a return)
84 ** couldbetty -- could be a tty (returns)
85 **
86 ** Returns:
87 ** Success:
88 ** on error:
89 ** SMNPT -- not seek opimized
90 ** SMOPT -- seek opimized
91 */
92
93 int
sm_whatbuf(fp,bufsize,couldbetty)94 sm_whatbuf(fp, bufsize, couldbetty)
95 register SM_FILE_T *fp;
96 size_t *bufsize;
97 int *couldbetty;
98 {
99 struct stat st;
100
101 if (fp->f_file < 0 || fstat(fp->f_file, &st) < 0)
102 {
103 *couldbetty = 0;
104 *bufsize = SM_IO_BUFSIZ;
105 return SMNPT;
106 }
107
108 /* could be a tty iff it is a character device */
109 *couldbetty = S_ISCHR(st.st_mode);
110 if (st.st_blksize == 0)
111 {
112 *bufsize = SM_IO_BUFSIZ;
113 return SMNPT;
114 }
115
116 #if SM_IO_MAX_BUF_FILE > 0
117 if (S_ISREG(st.st_mode) && st.st_blksize > SM_IO_MAX_BUF_FILE)
118 st.st_blksize = SM_IO_MAX_BUF_FILE;
119 #endif /* SM_IO_MAX_BUF_FILE > 0 */
120
121 #if SM_IO_MAX_BUF > 0 || SM_IO_MIN_BUF > 0
122 if (!S_ISREG(st.st_mode))
123 {
124 # if SM_IO_MAX_BUF > 0
125 if (st.st_blksize > SM_IO_MAX_BUF)
126 st.st_blksize = SM_IO_MAX_BUF;
127 # if SM_IO_MIN_BUF > 0
128 else
129 # endif /* SM_IO_MIN_BUF > 0 */
130 # endif /* SM_IO_MAX_BUF > 0 */
131 # if SM_IO_MIN_BUF > 0
132 if (st.st_blksize < SM_IO_MIN_BUF)
133 st.st_blksize = SM_IO_MIN_BUF;
134 # endif /* SM_IO_MIN_BUF > 0 */
135 }
136 #endif /* SM_IO_MAX_BUF > 0 || SM_IO_MIN_BUF > 0 */
137
138 /*
139 ** Optimise fseek() only if it is a regular file. (The test for
140 ** sm_std_seek is mainly paranoia.) It is safe to set _blksize
141 ** unconditionally; it will only be used if SMOPT is also set.
142 */
143
144 if ((fp->f_flags & SMSTR) == 0)
145 {
146 *bufsize = st.st_blksize;
147 fp->f_blksize = st.st_blksize;
148 }
149 else
150 *bufsize = SM_IO_BUFSIZ;
151 if ((st.st_mode & S_IFMT) == S_IFREG &&
152 fp->f_seek == sm_stdseek)
153 return SMOPT;
154 else
155 return SMNPT;
156 }
157