GetProp.c revision eb411b4b 
1/*
2
3Copyright 1986, 1998  The Open Group
4
5Permission to use, copy, modify, distribute, and sell this software and its
6documentation for any purpose is hereby granted without fee, provided that
7the above copyright notice appear in all copies and that both that
8copyright notice and this permission notice appear in supporting
9documentation.
10
11The above copyright notice and this permission notice shall be included in
12all copies or substantial portions of the Software.
13
14THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
17OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
18AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
19CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
20
21Except as contained in this notice, the name of The Open Group shall not be
22used in advertising or otherwise to promote the sale, use or other dealings
23in this Software without prior written authorization from The Open Group.
24
25*/
26
27#ifdef HAVE_CONFIG_H
28#include <config.h>
29#endif
30#include "Xlibint.h"
31#include <limits.h>
32
33int
34XGetWindowProperty(
35    register Display *dpy,
36    Window w,
37    Atom property,
38    long offset,
39    long length,
40    Bool delete,
41    Atom req_type,
42    Atom *actual_type,		/* RETURN */
43    int *actual_format,  	/* RETURN  8, 16, or 32 */
44    unsigned long *nitems, 	/* RETURN  # of 8-, 16-, or 32-bit entities */
45    unsigned long *bytesafter,	/* RETURN */
46    unsigned char **prop)	/* RETURN */
47{
48    xGetPropertyReply reply;
49    register xGetPropertyReq *req;
50    xError error = {0};
51
52    /* Always initialize return values, in case callers fail to initialize
53       them and fail to check the return code for an error. */
54    *actual_type = None;
55    *actual_format = 0;
56    *nitems = *bytesafter = 0L;
57    *prop = (unsigned char *) NULL;
58
59    LockDisplay(dpy);
60    GetReq (GetProperty, req);
61    req->window = w;
62    req->property = property;
63    req->type = req_type;
64    req->delete = delete;
65    req->longOffset = offset;
66    req->longLength = length;
67    error.sequenceNumber = dpy->request;
68
69    if (!_XReply (dpy, (xReply *) &reply, 0, xFalse)) {
70	UnlockDisplay(dpy);
71	SyncHandle();
72	return (1);	/* not Success */
73	}
74
75    if (reply.propertyType != None) {
76	unsigned long nbytes, netbytes;
77	int format = reply.format;
78
79      /*
80       * Protect against both integer overflow and just plain oversized
81       * memory allocation - no server should ever return this many props.
82       */
83	if (reply.nItems >= (INT_MAX >> 4))
84	    format = -1;	/* fall through to default error case */
85
86	switch (format) {
87      /*
88       * One extra byte is malloced than is needed to contain the property
89       * data, but this last byte is null terminated and convenient for
90       * returning string properties, so the client doesn't then have to
91       * recopy the string to make it null terminated.
92       */
93	  case 8:
94	    nbytes = netbytes = reply.nItems;
95	    if (nbytes + 1 > 0 && (*prop = Xmalloc (nbytes + 1)))
96		_XReadPad (dpy, (char *) *prop, netbytes);
97	    break;
98
99	  case 16:
100	    nbytes = reply.nItems * sizeof (short);
101	    netbytes = reply.nItems << 1;
102	    if (nbytes + 1 > 0 && (*prop = Xmalloc (nbytes + 1)))
103		_XRead16Pad (dpy, (short *) *prop, netbytes);
104	    break;
105
106	  case 32:
107	    nbytes = reply.nItems * sizeof (long);
108	    netbytes = reply.nItems << 2;
109	    if (nbytes + 1 > 0 && (*prop = Xmalloc (nbytes + 1)))
110		_XRead32 (dpy, (long *) *prop, netbytes);
111	    break;
112
113	  default:
114	    /*
115	     * This part of the code should never be reached.  If it is,
116	     * the server sent back a property with an invalid format.
117	     * This is a BadImplementation error.
118	     */
119	    {
120		/* sequence number stored above */
121		error.type = X_Error;
122		error.majorCode = X_GetProperty;
123		error.minorCode = 0;
124		error.errorCode = BadImplementation;
125		_XError(dpy, &error);
126	    }
127	    nbytes = netbytes = 0L;
128	    break;
129	}
130	if (! *prop) {
131	    _XEatDataWords(dpy, reply.length);
132	    UnlockDisplay(dpy);
133	    SyncHandle();
134	    return(BadAlloc);	/* not Success */
135	}
136	(*prop)[nbytes] = '\0';
137    }
138    *actual_type = reply.propertyType;
139    *actual_format = reply.format;
140    *nitems = reply.nItems;
141    *bytesafter = reply.bytesAfter;
142    UnlockDisplay(dpy);
143    SyncHandle();
144    return(Success);
145}
146
147