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Commit | Line | Data |
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99605d62 BP |
1 | /* |
2 | * Generic implementation of background process infrastructure. | |
3 | */ | |
4 | #include "sub-process.h" | |
5 | #include "sigchain.h" | |
6 | #include "pkt-line.h" | |
7 | ||
7663cdc8 | 8 | int cmd2process_cmp(const void *unused_cmp_data, |
9ab42958 SB |
9 | const void *entry, |
10 | const void *entry_or_key, | |
7663cdc8 | 11 | const void *unused_keydata) |
99605d62 | 12 | { |
9ab42958 SB |
13 | const struct subprocess_entry *e1 = entry; |
14 | const struct subprocess_entry *e2 = entry_or_key; | |
15 | ||
99605d62 BP |
16 | return strcmp(e1->cmd, e2->cmd); |
17 | } | |
18 | ||
19 | struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd) | |
20 | { | |
21 | struct subprocess_entry key; | |
22 | ||
23 | hashmap_entry_init(&key, strhash(cmd)); | |
24 | key.cmd = cmd; | |
25 | return hashmap_get(hashmap, &key, NULL); | |
26 | } | |
27 | ||
4f2a2e9f | 28 | int subprocess_read_status(int fd, struct strbuf *status) |
99605d62 BP |
29 | { |
30 | struct strbuf **pair; | |
31 | char *line; | |
4f2a2e9f BP |
32 | int len; |
33 | ||
99605d62 | 34 | for (;;) { |
4f2a2e9f BP |
35 | len = packet_read_line_gently(fd, NULL, &line); |
36 | if ((len < 0) || !line) | |
99605d62 BP |
37 | break; |
38 | pair = strbuf_split_str(line, '=', 2); | |
39 | if (pair[0] && pair[0]->len && pair[1]) { | |
40 | /* the last "status=<foo>" line wins */ | |
41 | if (!strcmp(pair[0]->buf, "status=")) { | |
42 | strbuf_reset(status); | |
43 | strbuf_addbuf(status, pair[1]); | |
44 | } | |
45 | } | |
46 | strbuf_list_free(pair); | |
47 | } | |
4f2a2e9f BP |
48 | |
49 | return (len < 0) ? len : 0; | |
99605d62 BP |
50 | } |
51 | ||
52 | void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry) | |
53 | { | |
54 | if (!entry) | |
55 | return; | |
56 | ||
57 | entry->process.clean_on_exit = 0; | |
58 | kill(entry->process.pid, SIGTERM); | |
59 | finish_command(&entry->process); | |
60 | ||
61 | hashmap_remove(hashmap, entry, NULL); | |
62 | } | |
63 | ||
64 | static void subprocess_exit_handler(struct child_process *process) | |
65 | { | |
66 | sigchain_push(SIGPIPE, SIG_IGN); | |
67 | /* Closing the pipe signals the subprocess to initiate a shutdown. */ | |
68 | close(process->in); | |
69 | close(process->out); | |
70 | sigchain_pop(SIGPIPE); | |
71 | /* Finish command will wait until the shutdown is complete. */ | |
72 | finish_command(process); | |
73 | } | |
74 | ||
75 | int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd, | |
76 | subprocess_start_fn startfn) | |
77 | { | |
78 | int err; | |
79 | struct child_process *process; | |
99605d62 BP |
80 | |
81 | entry->cmd = cmd; | |
82 | process = &entry->process; | |
83 | ||
84 | child_process_init(process); | |
2944a94c | 85 | argv_array_push(&process->args, cmd); |
99605d62 BP |
86 | process->use_shell = 1; |
87 | process->in = -1; | |
88 | process->out = -1; | |
89 | process->clean_on_exit = 1; | |
90 | process->clean_on_exit_handler = subprocess_exit_handler; | |
91 | ||
92 | err = start_command(process); | |
93 | if (err) { | |
94 | error("cannot fork to run subprocess '%s'", cmd); | |
95 | return err; | |
96 | } | |
97 | ||
98 | hashmap_entry_init(entry, strhash(cmd)); | |
99 | ||
100 | err = startfn(entry); | |
101 | if (err) { | |
102 | error("initialization for subprocess '%s' failed", cmd); | |
103 | subprocess_stop(hashmap, entry); | |
104 | return err; | |
105 | } | |
106 | ||
107 | hashmap_add(hashmap, entry); | |
108 | return 0; | |
109 | } | |
fa64a2fd JT |
110 | |
111 | static int handshake_version(struct child_process *process, | |
112 | const char *welcome_prefix, int *versions, | |
113 | int *chosen_version) | |
114 | { | |
115 | int version_scratch; | |
116 | int i; | |
117 | char *line; | |
118 | const char *p; | |
119 | ||
120 | if (!chosen_version) | |
121 | chosen_version = &version_scratch; | |
122 | ||
123 | if (packet_write_fmt_gently(process->in, "%s-client\n", | |
124 | welcome_prefix)) | |
125 | return error("Could not write client identification"); | |
126 | for (i = 0; versions[i]; i++) { | |
127 | if (packet_write_fmt_gently(process->in, "version=%d\n", | |
128 | versions[i])) | |
129 | return error("Could not write requested version"); | |
130 | } | |
131 | if (packet_flush_gently(process->in)) | |
132 | return error("Could not write flush packet"); | |
133 | ||
134 | if (!(line = packet_read_line(process->out, NULL)) || | |
135 | !skip_prefix(line, welcome_prefix, &p) || | |
136 | strcmp(p, "-server")) | |
137 | return error("Unexpected line '%s', expected %s-server", | |
138 | line ? line : "<flush packet>", welcome_prefix); | |
139 | if (!(line = packet_read_line(process->out, NULL)) || | |
140 | !skip_prefix(line, "version=", &p) || | |
141 | strtol_i(p, 10, chosen_version)) | |
142 | return error("Unexpected line '%s', expected version", | |
143 | line ? line : "<flush packet>"); | |
144 | if ((line = packet_read_line(process->out, NULL))) | |
145 | return error("Unexpected line '%s', expected flush", line); | |
146 | ||
147 | /* Check to make sure that the version received is supported */ | |
148 | for (i = 0; versions[i]; i++) { | |
149 | if (versions[i] == *chosen_version) | |
150 | break; | |
151 | } | |
152 | if (!versions[i]) | |
153 | return error("Version %d not supported", *chosen_version); | |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
158 | static int handshake_capabilities(struct child_process *process, | |
159 | struct subprocess_capability *capabilities, | |
160 | unsigned int *supported_capabilities) | |
161 | { | |
162 | int i; | |
163 | char *line; | |
164 | ||
165 | for (i = 0; capabilities[i].name; i++) { | |
166 | if (packet_write_fmt_gently(process->in, "capability=%s\n", | |
167 | capabilities[i].name)) | |
168 | return error("Could not write requested capability"); | |
169 | } | |
170 | if (packet_flush_gently(process->in)) | |
171 | return error("Could not write flush packet"); | |
172 | ||
173 | while ((line = packet_read_line(process->out, NULL))) { | |
174 | const char *p; | |
175 | if (!skip_prefix(line, "capability=", &p)) | |
176 | continue; | |
177 | ||
178 | for (i = 0; | |
179 | capabilities[i].name && strcmp(p, capabilities[i].name); | |
180 | i++) | |
181 | ; | |
182 | if (capabilities[i].name) { | |
183 | if (supported_capabilities) | |
184 | *supported_capabilities |= capabilities[i].flag; | |
185 | } else { | |
ab46e6fc JH |
186 | die("subprocess '%s' requested unsupported capability '%s'", |
187 | process->argv[0], p); | |
fa64a2fd JT |
188 | } |
189 | } | |
190 | ||
191 | return 0; | |
192 | } | |
193 | ||
194 | int subprocess_handshake(struct subprocess_entry *entry, | |
195 | const char *welcome_prefix, | |
196 | int *versions, | |
197 | int *chosen_version, | |
198 | struct subprocess_capability *capabilities, | |
199 | unsigned int *supported_capabilities) | |
200 | { | |
201 | int retval; | |
202 | struct child_process *process = &entry->process; | |
203 | ||
204 | sigchain_push(SIGPIPE, SIG_IGN); | |
205 | ||
206 | retval = handshake_version(process, welcome_prefix, versions, | |
207 | chosen_version) || | |
208 | handshake_capabilities(process, capabilities, | |
209 | supported_capabilities); | |
210 | ||
211 | sigchain_pop(SIGPIPE); | |
212 | return retval; | |
213 | } |