xref: /illumos-gate/usr/src/cmd/sendmail/libsm/fflush.c (revision 445f2479)
1 /*
2  * Copyright (c) 2000-2001, 2005, 2006 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: fflush.c,v 1.45 2006/03/03 22:25:00 ca Exp $")
19 #include <unistd.h>
20 #include <errno.h>
21 #include <sm/time.h>
22 #include <signal.h>
23 #include <fcntl.h>
24 #include <string.h>
25 #include <sm/io.h>
26 #include <sm/assert.h>
27 #include <sm/setjmp.h>
28 #include "local.h"
29 #include <sm/conf.h>
30 
31 /*
32 **  SM_IO_FLUSH -- flush the buffer for a 'fp' to the "file"
33 **
34 **  Flush a single file. We don't allow this function to flush
35 **  all open files when fp==NULL any longer.
36 **
37 **	Parameters:
38 **		fp -- the file pointer buffer to flush
39 **		timeout -- time to complete the flush
40 **
41 **	Results:
42 **		Failure: SM_IO_EOF and sets errno
43 **		Success: 0 (zero)
44 */
45 
46 int
47 sm_io_flush(fp, timeout)
48 	register SM_FILE_T *fp;
49 	int SM_NONVOLATILE timeout;
50 {
51 	int fd;
52 	struct timeval to;
53 
54 	SM_REQUIRE_ISA(fp, SmFileMagic);
55 
56 	if ((fp->f_flags & (SMWR | SMRW)) == 0)
57 	{
58 		/*
59 		**  The file is not opened for writing, so it cannot be flushed
60 		**  (writable means SMWR [write] or SMRW [read/write].
61 		*/
62 
63 		errno = EBADF;
64 		return SM_IO_EOF;
65 	}
66 
67 	SM_CONVERT_TIME(fp, fd, timeout, &to);
68 
69 	/* Now do the flush */
70 	return sm_flush(fp, (int *) &timeout);
71 }
72 
73 /*
74 **  SM_FLUSH -- perform the actual flush
75 **
76 **  Assumes that 'fp' has been validated before this function called.
77 **
78 **	Parameters:
79 **		fp -- file pointer to be flushed
80 **		timeout -- max time allowed for flush (milliseconds)
81 **
82 **	Results:
83 **		Success: 0 (zero)
84 **		Failure: SM_IO_EOF and errno set
85 **
86 **	Side Effects:
87 **		timeout will get updated with the time remaining (if any)
88 */
89 
90 int
sm_flush(fp,timeout)91 sm_flush(fp, timeout)
92 	register SM_FILE_T *fp;
93 	int *timeout;
94 {
95 	register unsigned char *p;
96 	register int n, t;
97 	int fd;
98 
99 	SM_REQUIRE_ISA(fp, SmFileMagic);
100 
101 	t = fp->f_flags;
102 	if ((t & SMWR) == 0)
103 		return 0;
104 
105 	if (t & SMSTR)
106 	{
107 		*fp->f_p = '\0';
108 		return 0;
109 	}
110 
111 	if ((p = fp->f_bf.smb_base) == NULL)
112 		return 0;
113 
114 	n = fp->f_p - p;		/* write this much */
115 
116 	if ((fd = sm_io_getinfo(fp, SM_IO_WHAT_FD, NULL)) == -1)
117 	{
118 		/* can't get an fd, likely internal 'fake' fp */
119 		errno = 0;
120 		fd = -1;
121 	}
122 
123 	/*
124 	**  Set these immediately to avoid problems with longjmp and to allow
125 	**  exchange buffering (via setvbuf) in user write function.
126 	*/
127 
128 	fp->f_p = p;
129 	fp->f_w = t & (SMLBF|SMNBF) ? 0 : fp->f_bf.smb_size; /* implies SMFBF */
130 
131 	for (; n > 0; n -= t, p += t)
132 	{
133 		errno = 0; /* needed to ensure EOF correctly found */
134 
135 		/* Call the file type's write function */
136 		t = (*fp->f_write)(fp, (char *)p, n);
137 		if (t <= 0)
138 		{
139 			if (t == 0 && errno == 0)
140 				break; /* EOF found */
141 
142 			if (IS_IO_ERROR(fd, t, *timeout))
143 			{
144 				fp->f_flags |= SMERR;
145 
146 				/* errno set by fp->f_write */
147 				return SM_IO_EOF;
148 			}
149 			SM_IO_WR_TIMEOUT(fp, fd, *timeout);
150 			t = 0;
151 		}
152 	}
153 	return 0;
154 }
155