1IMCLIENT(3) Library Functions Manual IMCLIENT(3)
2 *
6
8 imclient library - authenticating callback interface to IMAP/IMSP
9 servers
10
12 #include <cyrus/imclient.h>
13 int imclient_connect(struct imclient **imclient, const char *host,
15 const char *port);
16 void imclient_close (struct imclient *imclient);
18 void imclient_setflags(struct imclient *imclient, intflags);
19 void imclient_clearflags (struct imclient *imclient, intflags);
20 char* imclient_servername (struct imclient *imclient);
21 void imclient_addcallback (struct imclient * imclient ,...);
22 void imclient_send (struct imclient *imclient, void (*finishproc)(),
23 void *finishrock, const char *fmt, ...);
24 void imclient_getselectinfo (struct imclient *imclient, int *fd, int *
25 wanttowrite);
26 void imclient_processoneevent (struct imclient *imclient);
27 int imclient_authenticate (struct imclient *imclient, struct
28 sasl_client **availmech, const char *service, const char *user, int
29 protallowed);
30 int imclient_havetls ();
31 int imclient_starttls (struct imclient *imclient, char *cert_file, char
32 *key_file, char *CAfile, char *CApath);
33
36 The imclient library functions are distributed with Cyrus IMAP and
37 IMSP. These functions are used for building IMAP/IMSP client software.
38 These functions handle Kerberos authentication and can set callbacks
39 based on the keyword in untagged replies or based on the command tag at
40 the end of command replies.
41 Users must link with the -lcyrus switch, and must supply a function
43 called fatal to be called in case of any error within libcyrus.a.
44 All of the imclient functions begin with the prefix imclient and takes
46 an argument of type struct imclient * as the first argument which is
47 initialized by imclient_connect and freed by imclient_close.
48 See below for a description of each function.
50 imclient_connect()
53 Connects the client server to the host. If successful, it returns
54 0 and sets the imclient argument to a pointer to an imclient
55 struct. The imclient struct represents the current connection,
56 flags, and callbacks. On failure, the current errno is returned
57 if a system call failed, -1 is returned if the host name was not
58 found, and -2 is returned if the service name was not found.
59 imclient_close()
61 Closes and frees the imclient connection.
62 imclient_setflags()
64 Sets the flags specified by the flags argument on the imclient
65 connection. Currently the only flag allowed is IMCLIENT_CONN_NON‐
66 SYNCLITERAL (this flag indicates that the server supports non-syn‐
67 chronizing literals described by the LITERAL+ extension).
68 imclient_clearflags()
70 Clears the flags specified by the flags argument on the imclient
71 connection.
72 imclient_servername()
74 Returns a char * pointer to the name of the server connected to
75 by imclient.
76 imclient_addcallback()
78 Adds an untagged data callback to the imclient connection. The
79 function imclient_addcallback takes callbacks of the type
80 imclient_proc_t which is defined to be:
81 typedef void imclient_proc_t (struct imclient *imclient, void
82 *rock, struct imclient_reply *reply);
83 and struct imclient_reply * is defined to be:
84 struct imclient_reply {
85 char *keyword;
86 long msgno;
87 char *text;
88 };
89 After the first argument imclient, there can be zero or more
91 instances of the set of keyword, flags, proc, and rock, each
92 adding or changing a single callback. Each instance adds or
93 changes the callback for keyword. The argument, flags, specifies
94 information about the parsing of the untagged data. proc and rock
95 specify the callback function and rock to invoke when the untagged
96 data is received. proc may be a null pointer, in which case no
97 function is invoked. The callback function may not call the func‐
98 tions imclient_close(), imclient_send(), imclient_eof(),
99 imclient_processoneevent(), or imclient_authenticate() on the con‐
100 nection. The callback function may over write the text of
101 untagged data.
102 imclient_send()
104 Sends a new command to the imclient connection. finishproc and
105 finnishrock are the function and rock called when the command
106 completes. functionproc may be a null pointer, in which case no
107 callback is made. The call back function may not call the func‐
108 tions imclient_close(), imclient_send(), imclient_eof(),
109 imclient_processoneevent(), or imclient_authenticate() on the con‐
110 nection. The argument, fmt , is a print like specification of the
111 command. It must not include the tag as the tag is automatically
112 added by imclient_send(). The defined %-sequences are:
113 %% for %
114 %a for an IMAP atom
115 %s for an astring (which will be quoted or literalized as
116 needed)
117 %d for a decimal
118 %u for an unsigned decimal
119 %v for #astring (argument is a null-terminated array of char *
120 which are written as space separated astrings)
121 imclient_getselectinfo()
123 Gets the information for calling select(2). fd is filled in with
124 the file descriptor to select(2) for read. wanttowrite is filled
125 in with a nonzero value if select should be used for write as
126 well.
127 imclient_processoneevent()
129 Processes one input or output event on the imclient connection.
130 imclient_authenticate()
132 Authenticates the imclient connection using one of the mechanisms
133 in availmech. The argument, user, if not NULL, specifies the user
134 to authenticate as. If the user is NULL, the current user is used.
135 The argument protallowed is a bitmask of permissible protection
136 mechanisms.
137 On success, 0 is returned. On failure (i.e., "BAD" keyboard, or
138 no authentication mechanisms worked), 1 is returned. On extreme
139 failure (premature "OK"), 2 is returned.
140 imclient_havetls()
142 Returns a Boolean indicating whether the imclient library was com‐
143 piled with TLS (SSL) support. If so, imclient_starttls() may be
144 used to secure the IMAP connection.
145 imclient_starttls()
147 Issues a STARTTLS command on an existing IMAP connection and nego‐
148 tiates the secure link. The cert_file and key_file arguments
149 specify the client certificate and secret key to use to authenti‐
150 cate ourselves to the server. If client authentication is not
151 needed, set both of these arguments to NULL.
152 The CAfile and CApath arguments specify a file or directory,
154 respectively, of CA certificates for validating server certifi‐
155 cates. (See SSL_CTX_load_verify_locations(3) for details.) If
156 both of these are NULL, the client will be unable to validate the
157 server's certificate, in which case the connection may succeed but
158 a warning will be printed to stdout.
159
162 The following code is a possible skeletion of imclient that relies on
163 Kerberos to do authentication. This code preforms an IMAP CAPABILITY
164 request and prints out the result.
165 struct sasl_client;
167 #include <cyrus/xmalloc.h> /* example uses xstrdup */
168 #include <cyrus/sasl.h>
169 #include <cyrus/imclient.h>
170 #include <stdio.h>
171 extern struct sasl_client krb_sasl_client;
173 struct sasl_client *login_sasl_client[] = {
175 &krb_sasl_client,
176 NULL
177 };
178 struct imclient *imclient;
179 char server[] = "cyrus.andrew.cmu.edu" ;
180 char port[] = "imap";
181 void fatal(char* message, int rc) {
183 fprintf(stderr, "fatal error: %s\n", message);
184 exit(rc);
185 }
186 static void callback_capability(struct imclient *imclient,
188 void *rock,
189 struct imclient_reply *reply) {
190 if (reply->text != NULL) {
191 *((char**)rock) = xstrdup( reply->text );
192 }
193 }
194 static void end_command (struct imclient *connection, void*
196 rock, struct imclient_reply *inmsg) {
197 (*(int*)rock)--;
198 }
199 main() {
201 char* capability_string;
202 int nc;
203 if (imclient_connect(&imclient, server, port)) {
205 fprintf(stderr,
206 "error: Couldn't connect to %s %s\n",
207 server, port);
208 exit(1);
209 }
210 if (imclient_authenticate(imclient, login_sasl_client, "imap"
212 /* service */,
213 NULL /* user */, SASL_PROT_ANY)) {
214 exit(1);
215 }
216 imclient_addcallback(imclient, "CAPABILITY",
218 CALLBACK_NOLITERAL,
219 callback_capability,
220 &capability_string,
221 NULL);
222 nc = 1;
224 imclient_send(imclient, end_command,
226 (void*) &nc, "CAPABILITY");
227 while(nc > 0) {
229 imclient_processoneevent(imclient);
230 }
231 if (strstr("LITERAL+", capability_string)) {
233 imclient_setflags(imclient, IMCLIENT_CONN_NONSYNCLITERAL);
234 }
235 imclient_send(imclient, NULL, NULL, "LOGOUT");
237 imclient_close(imclient);
238 printf("capability text is: %s\n", capability_string);
240 free(capability_string);
242 }
243
246 No known bugs.
247
250 cyradm, imapd, imspd, RFC2033 (IMAP LITERAL+ extension), RFC2060
251 (IMAP4rev1 specification), and select(2)
252
255 IMAP, ACAP, IMSP, Kerberos, Authentication
256CMU Project Cyrus IMCLIENT(3)