config: fix a leak in git_config_copy_or_rename_section_in_file
[alt-git.git] / credential.h
blobb8e2936d1dcb978d67fb6660c6ee288d9a26dfc5
1 #ifndef CREDENTIAL_H
2 #define CREDENTIAL_H
4 #include "string-list.h"
5 #include "strvec.h"
7 /**
8 * The credentials API provides an abstracted way of gathering username and
9 * password credentials from the user.
11 * Typical setup
12 * -------------
14 * ------------
15 * +-----------------------+
16 * | Git code (C) |--- to server requiring --->
17 * | | authentication
18 * |.......................|
19 * | C credential API |--- prompt ---> User
20 * +-----------------------+
21 * ^ |
22 * | pipe |
23 * | v
24 * +-----------------------+
25 * | Git credential helper |
26 * +-----------------------+
27 * ------------
29 * The Git code (typically a remote-helper) will call the C API to obtain
30 * credential data like a login/password pair (credential_fill). The
31 * API will itself call a remote helper (e.g. "git credential-cache" or
32 * "git credential-store") that may retrieve credential data from a
33 * store. If the credential helper cannot find the information, the C API
34 * will prompt the user. Then, the caller of the API takes care of
35 * contacting the server, and does the actual authentication.
37 * C API
38 * -----
40 * The credential C API is meant to be called by Git code which needs to
41 * acquire or store a credential. It is centered around an object
42 * representing a single credential and provides three basic operations:
43 * fill (acquire credentials by calling helpers and/or prompting the user),
44 * approve (mark a credential as successfully used so that it can be stored
45 * for later use), and reject (mark a credential as unsuccessful so that it
46 * can be erased from any persistent storage).
48 * Example
49 * ~~~~~~~
51 * The example below shows how the functions of the credential API could be
52 * used to login to a fictitious "foo" service on a remote host:
54 * -----------------------------------------------------------------------
55 * int foo_login(struct foo_connection *f)
56 * {
57 * int status;
58 * // Create a credential with some context; we don't yet know the
59 * // username or password.
61 * struct credential c = CREDENTIAL_INIT;
62 * c.protocol = xstrdup("foo");
63 * c.host = xstrdup(f->hostname);
65 * // Fill in the username and password fields by contacting
66 * // helpers and/or asking the user. The function will die if it
67 * // fails.
68 * credential_fill(&c);
70 * // Otherwise, we have a username and password. Try to use it.
72 * status = send_foo_login(f, c.username, c.password);
73 * switch (status) {
74 * case FOO_OK:
75 * // It worked. Store the credential for later use.
76 * credential_accept(&c);
77 * break;
78 * case FOO_BAD_LOGIN:
79 * // Erase the credential from storage so we don't try it again.
80 * credential_reject(&c);
81 * break;
82 * default:
83 * // Some other error occurred. We don't know if the
84 * // credential is good or bad, so report nothing to the
85 * // credential subsystem.
86 * }
88 * // Free any associated resources.
89 * credential_clear(&c);
91 * return status;
92 * }
93 * -----------------------------------------------------------------------
97 /**
98 * This struct represents a single username/password combination
99 * along with any associated context. All string fields should be
100 * heap-allocated (or NULL if they are not known or not applicable).
101 * The meaning of the individual context fields is the same as
102 * their counterparts in the helper protocol.
104 * This struct should always be initialized with `CREDENTIAL_INIT` or
105 * `credential_init`.
107 struct credential {
110 * A `string_list` of helpers. Each string specifies an external
111 * helper which will be run, in order, to either acquire or store
112 * credentials. This list is filled-in by the API functions
113 * according to the corresponding configuration variables before
114 * consulting helpers, so there usually is no need for a caller to
115 * modify the helpers field at all.
117 struct string_list helpers;
120 * A `strvec` of WWW-Authenticate header values. Each string
121 * is the value of a WWW-Authenticate header in an HTTP response,
122 * in the order they were received in the response.
124 struct strvec wwwauth_headers;
127 * Internal use only. Keeps track of if we previously matched against a
128 * WWW-Authenticate header line in order to re-fold future continuation
129 * lines into one value.
131 unsigned header_is_last_match:1;
133 unsigned approved:1,
134 configured:1,
135 quit:1,
136 use_http_path:1,
137 username_from_proto:1;
139 char *username;
140 char *password;
141 char *protocol;
142 char *host;
143 char *path;
144 char *oauth_refresh_token;
145 timestamp_t password_expiry_utc;
148 #define CREDENTIAL_INIT { \
149 .helpers = STRING_LIST_INIT_DUP, \
150 .password_expiry_utc = TIME_MAX, \
151 .wwwauth_headers = STRVEC_INIT, \
154 /* Initialize a credential structure, setting all fields to empty. */
155 void credential_init(struct credential *);
158 * Free any resources associated with the credential structure, returning
159 * it to a pristine initialized state.
161 void credential_clear(struct credential *);
164 * Instruct the credential subsystem to fill the username and
165 * password fields of the passed credential struct by first
166 * consulting helpers, then asking the user. After this function
167 * returns, the username and password fields of the credential are
168 * guaranteed to be non-NULL. If an error occurs, the function will
169 * die().
171 void credential_fill(struct credential *);
174 * Inform the credential subsystem that the provided credentials
175 * were successfully used for authentication. This will cause the
176 * credential subsystem to notify any helpers of the approval, so
177 * that they may store the result to be used again. Any errors
178 * from helpers are ignored.
180 void credential_approve(struct credential *);
183 * Inform the credential subsystem that the provided credentials
184 * have been rejected. This will cause the credential subsystem to
185 * notify any helpers of the rejection (which allows them, for
186 * example, to purge the invalid credentials from storage). It
187 * will also free() the username and password fields of the
188 * credential and set them to NULL (readying the credential for
189 * another call to `credential_fill`). Any errors from helpers are
190 * ignored.
192 void credential_reject(struct credential *);
194 int credential_read(struct credential *, FILE *);
195 void credential_write(const struct credential *, FILE *);
198 * Parse a url into a credential struct, replacing any existing contents.
200 * If the url can't be parsed (e.g., a missing "proto://" component), the
201 * resulting credential will be empty and the function will return an
202 * error (even in the "gently" form).
204 * If we encounter a component which cannot be represented as a credential
205 * value (e.g., because it contains a newline), the "gently" form will return
206 * an error but leave the broken state in the credential object for further
207 * examination. The non-gentle form will issue a warning to stderr and return
208 * an empty credential.
210 void credential_from_url(struct credential *, const char *url);
211 int credential_from_url_gently(struct credential *, const char *url, int quiet);
213 int credential_match(const struct credential *want,
214 const struct credential *have);
216 #endif /* CREDENTIAL_H */