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