xref: /titanic_51/usr/src/lib/libast/common/sfio/_sfopen.c (revision 37714ae43602c675f9dc59b070bfdf9fa702872c)
1 /***********************************************************************
2 *                                                                      *
3 *               This software is part of the ast package               *
4 *          Copyright (c) 1985-2008 AT&T Intellectual Property          *
5 *                      and is licensed under the                       *
6 *                  Common Public License, Version 1.0                  *
7 *                    by AT&T Intellectual Property                     *
8 *                                                                      *
9 *                A copy of the License is available at                 *
10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
12 *                                                                      *
13 *              Information and Software Systems Research               *
14 *                            AT&T Research                             *
15 *                           Florham Park NJ                            *
16 *                                                                      *
17 *                 Glenn Fowler <gsf@research.att.com>                  *
18 *                  David Korn <dgk@research.att.com>                   *
19 *                   Phong Vo <kpv@research.att.com>                    *
20 *                                                                      *
21 ***********************************************************************/
22 #include	"sfhdr.h"
23 
24 /*	Open a file/string for IO.
25 **	If f is not nil, it is taken as an existing stream that should be
26 **	closed and its structure reused for the new stream.
27 **
28 **	Written by Kiem-Phong Vo.
29 */
30 
31 #if _BLD_sfio && defined(__EXPORT__)
32 #define extern  __EXPORT__
33 #endif
34 extern
35 #undef  extern
36 
37 #if __STD_C
38 Sfio_t* _sfopen(Sfio_t* f, const char* file, const char* mode)
39 #else
40 Sfio_t* _sfopen(f,file,mode)
41 Sfio_t*		f;		/* old stream structure */
42 char*		file;		/* file/string to be opened */
43 char*		mode;		/* mode of the stream */
44 #endif
45 {
46 	int	fd, oldfd, oflags, sflags;
47 	SFMTXDECL(f);
48 
49 	/* get the control flags */
50 	if((sflags = _sftype(mode,&oflags,NIL(int*))) == 0)
51 		return NIL(Sfio_t*);
52 
53 	/* changing the control flags */
54 	if(f && !file && !((f->flags|sflags)&SF_STRING) )
55 	{	SFMTXENTER(f, NIL(Sfio_t*));
56 
57 		if(f->mode&SF_INIT ) /* stream uninitialized, ok to set flags */
58 		{	f->flags |= (sflags & (SF_FLAGS & ~SF_RDWR));
59 
60 			if((sflags &= SF_RDWR) != 0) /* reset read/write modes */
61 			{	f->flags = (f->flags & ~SF_RDWR) | sflags;
62 
63 				if((f->flags&SF_RDWR) == SF_RDWR)
64 					f->bits |= SF_BOTH;
65 				else	f->bits &= ~SF_BOTH;
66 
67 				if(f->flags&SF_READ)
68 					f->mode = (f->mode&~SF_WRITE)|SF_READ;
69 				else	f->mode = (f->mode&~SF_READ)|SF_WRITE;
70 			}
71 		}
72 		else /* make sure there is no buffered data */
73 		{	if(sfsync(f) < 0)
74 				SFMTXRETURN(f,NIL(Sfio_t*));
75 		}
76 
77 		if(f->file >= 0 && (oflags &= (O_TEXT|O_BINARY|O_APPEND)) != 0 )
78 		{	/* set file access control */
79 			int ctl = sysfcntlf(f->file, F_GETFL, 0);
80 			ctl = (ctl & ~(O_TEXT|O_BINARY|O_APPEND)) | oflags;
81 			sysfcntlf(f->file, F_SETFL, ctl);
82 		}
83 
84 		SFMTXRETURN(f,f);
85 	}
86 
87 	if(sflags&SF_STRING)
88 	{	f = sfnew(f,(char*)file,
89 		  	  file ? (size_t)strlen((char*)file) : (size_t)SF_UNBOUND,
90 		  	  -1,sflags);
91 	}
92 	else
93 	{	if(!file)
94 			return NIL(Sfio_t*);
95 
96 #if _has_oflags /* open the file */
97 		while((fd = sysopenf((char*)file,oflags,SF_CREATMODE)) < 0 && errno == EINTR)
98 			errno = 0;
99 #else
100 		while((fd = sysopenf(file,oflags&O_ACCMODE)) < 0 && errno == EINTR)
101 			errno = 0;
102 		if(fd >= 0)
103 		{	if((oflags&(O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL) )
104 			{	CLOSE(fd);	/* error: file already exists */
105 				return NIL(Sfio_t*);
106 			}
107 			if(oflags&O_TRUNC )	/* truncate file */
108 			{	reg int	tf;
109 				while((tf = syscreatf(file,SF_CREATMODE)) < 0 &&
110 				      errno == EINTR)
111 					errno = 0;
112 				CLOSE(tf);
113 			}
114 		}
115 		else if(oflags&O_CREAT)
116 		{	while((fd = syscreatf(file,SF_CREATMODE)) < 0 && errno == EINTR)
117 				errno = 0;
118 			if((oflags&O_ACCMODE) != O_WRONLY)
119 			{	/* the file now exists, reopen it for read/write */
120 				CLOSE(fd);
121 				while((fd = sysopenf(file,oflags&O_ACCMODE)) < 0 &&
122 				      errno == EINTR)
123 					errno = 0;
124 			}
125 		}
126 #endif
127 		if(fd < 0)
128 			return NIL(Sfio_t*);
129 
130 		/* we may have to reset the file descriptor to its old value */
131 		oldfd = f ? f->file : -1;
132 		if((f = sfnew(f,NIL(char*),(size_t)SF_UNBOUND,fd,sflags)) && oldfd >= 0)
133 			(void)sfsetfd(f,oldfd);
134 	}
135 
136 	return f;
137 }
138 
139 #if __STD_C
140 int _sftype(reg const char* mode, int* oflagsp, int* uflagp)
141 #else
142 int _sftype(mode, oflagsp, uflagp)
143 reg char*	mode;
144 int*		oflagsp;
145 int*		uflagp;
146 #endif
147 {
148 	reg int	sflags, oflags, uflag;
149 
150 	if(!mode)
151 		return 0;
152 
153 	/* construct the open flags */
154 	sflags = oflags = uflag = 0;
155 	while(1) switch(*mode++)
156 	{
157 	case 'w' :
158 		sflags |= SF_WRITE;
159 		oflags |= O_WRONLY | O_CREAT;
160 		if(!(sflags&SF_READ))
161 			oflags |= O_TRUNC;
162 		continue;
163 	case 'a' :
164 		sflags |= SF_WRITE | SF_APPENDWR;
165 		oflags |= O_WRONLY | O_APPEND | O_CREAT;
166 		continue;
167 	case 'r' :
168 		sflags |= SF_READ;
169 		oflags |= O_RDONLY;
170 		continue;
171 	case 's' :
172 		sflags |= SF_STRING;
173 		continue;
174 	case 'b' :
175 		oflags |= O_BINARY;
176 		continue;
177 	case 't' :
178 		oflags |= O_TEXT;
179 		continue;
180 	case 'x' :
181 		oflags |= O_EXCL;
182 		continue;
183 	case '+' :
184 		if(sflags)
185 			sflags |= SF_READ|SF_WRITE;
186 		continue;
187 	case 'm' :
188 		sflags |= SF_MTSAFE;
189 		uflag = 0;
190 		continue;
191 	case 'u' :
192 		sflags &= ~SF_MTSAFE;
193 		uflag = 1;
194 		continue;
195 	case 'W' :
196 		sflags |= SF_WCWIDTH;
197 		uflag = 0;
198 		continue;
199 	default :
200 		if(!(oflags&O_CREAT) )
201 			oflags &= ~O_EXCL;
202 #if _WIN32 && !_WINIX
203 		if(!(oflags&(O_BINARY|O_TEXT)))
204 			oflags |= O_BINARY;
205 #endif
206 		if((sflags&SF_RDWR) == SF_RDWR)
207 			oflags = (oflags&~O_ACCMODE)|O_RDWR;
208 		if(oflagsp)
209 			*oflagsp = oflags;
210 		if(uflagp)
211 			*uflagp = uflag;
212 		if((sflags&(SF_STRING|SF_RDWR)) == SF_STRING)
213 			sflags |= SF_READ;
214 		return sflags;
215 	}
216 }
217