Merge branch 'jn/strbuf-doc-re-reuse' into maint
[alt-git.git] / sub-process.c
blob80571567f2a64be451fe2ac92c230f66fa04c844
1 /*
2 * Generic implementation of background process infrastructure.
3 */
4 #include "sub-process.h"
5 #include "sigchain.h"
6 #include "pkt-line.h"
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)
13 return strcmp(e1->cmd, e2->cmd);
16 struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd)
18 struct subprocess_entry key;
20 hashmap_entry_init(&key, strhash(cmd));
21 key.cmd = cmd;
22 return hashmap_get(hashmap, &key, NULL);
25 int subprocess_read_status(int fd, struct strbuf *status)
27 struct strbuf **pair;
28 char *line;
29 int len;
31 for (;;) {
32 len = packet_read_line_gently(fd, NULL, &line);
33 if ((len < 0) || !line)
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]);
43 strbuf_list_free(pair);
46 return (len < 0) ? len : 0;
49 void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry)
51 if (!entry)
52 return;
54 entry->process.clean_on_exit = 0;
55 kill(entry->process.pid, SIGTERM);
56 finish_command(&entry->process);
58 hashmap_remove(hashmap, entry, NULL);
61 static void subprocess_exit_handler(struct child_process *process)
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);
72 int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd,
73 subprocess_start_fn startfn)
75 int err;
76 struct child_process *process;
78 entry->cmd = cmd;
79 process = &entry->process;
81 child_process_init(process);
82 argv_array_push(&process->args, cmd);
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;
89 err = start_command(process);
90 if (err) {
91 error("cannot fork to run subprocess '%s'", cmd);
92 return err;
95 hashmap_entry_init(entry, strhash(cmd));
97 err = startfn(entry);
98 if (err) {
99 error("initialization for subprocess '%s' failed", cmd);
100 subprocess_stop(hashmap, entry);
101 return err;
104 hashmap_add(hashmap, entry);
105 return 0;
108 static int handshake_version(struct child_process *process,
109 const char *welcome_prefix, int *versions,
110 int *chosen_version)
112 int version_scratch;
113 int i;
114 char *line;
115 const char *p;
117 if (!chosen_version)
118 chosen_version = &version_scratch;
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");
128 if (packet_flush_gently(process->in))
129 return error("Could not write flush packet");
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);
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;
149 if (!versions[i])
150 return error("Version %d not supported", *chosen_version);
152 return 0;
155 static int handshake_capabilities(struct child_process *process,
156 struct subprocess_capability *capabilities,
157 unsigned int *supported_capabilities)
159 int i;
160 char *line;
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");
167 if (packet_flush_gently(process->in))
168 return error("Could not write flush packet");
170 while ((line = packet_read_line(process->out, NULL))) {
171 const char *p;
172 if (!skip_prefix(line, "capability=", &p))
173 continue;
175 for (i = 0;
176 capabilities[i].name && strcmp(p, capabilities[i].name);
177 i++)
179 if (capabilities[i].name) {
180 if (supported_capabilities)
181 *supported_capabilities |= capabilities[i].flag;
182 } else {
183 die("subprocess '%s' requested unsupported capability '%s'",
184 process->argv[0], p);
188 return 0;
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)
198 int retval;
199 struct child_process *process = &entry->process;
201 sigchain_push(SIGPIPE, SIG_IGN);
203 retval = handshake_version(process, welcome_prefix, versions,
204 chosen_version) ||
205 handshake_capabilities(process, capabilities,
206 supported_capabilities);
208 sigchain_pop(SIGPIPE);
209 return retval;