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