http-push: fix construction of hex value from path
[git/git.git] / sub-process.c
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1/*
2 * Generic implementation of background process infrastructure.
3 */
4#include "sub-process.h"
5#include "sigchain.h"
6#include "pkt-line.h"
7
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8int cmd2process_cmp(const void *unused_cmp_data,
9 const struct subprocess_entry *e1,
10 const struct subprocess_entry *e2,
11 const void *unused_keydata)
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12{
13 return strcmp(e1->cmd, e2->cmd);
14}
15
16struct 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 25int subprocess_read_status(int fd, struct strbuf *status)
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26{
27 struct strbuf **pair;
28 char *line;
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29 int len;
30
99605d62 31 for (;;) {
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32 len = packet_read_line_gently(fd, NULL, &line);
33 if ((len < 0) || !line)
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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 }
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45
46 return (len < 0) ? len : 0;
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47}
48
49void 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
61static 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
72int 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;
77 const char *argv[] = { cmd, NULL };
78
79 entry->cmd = cmd;
80 process = &entry->process;
81
82 child_process_init(process);
83 process->argv = argv;
84 process->use_shell = 1;
85 process->in = -1;
86 process->out = -1;
87 process->clean_on_exit = 1;
88 process->clean_on_exit_handler = subprocess_exit_handler;
89
90 err = start_command(process);
91 if (err) {
92 error("cannot fork to run subprocess '%s'", cmd);
93 return err;
94 }
95
96 hashmap_entry_init(entry, strhash(cmd));
97
98 err = startfn(entry);
99 if (err) {
100 error("initialization for subprocess '%s' failed", cmd);
101 subprocess_stop(hashmap, entry);
102 return err;
103 }
104
105 hashmap_add(hashmap, entry);
106 return 0;
107}
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108
109static int handshake_version(struct child_process *process,
110 const char *welcome_prefix, int *versions,
111 int *chosen_version)
112{
113 int version_scratch;
114 int i;
115 char *line;
116 const char *p;
117
118 if (!chosen_version)
119 chosen_version = &version_scratch;
120
121 if (packet_write_fmt_gently(process->in, "%s-client\n",
122 welcome_prefix))
123 return error("Could not write client identification");
124 for (i = 0; versions[i]; i++) {
125 if (packet_write_fmt_gently(process->in, "version=%d\n",
126 versions[i]))
127 return error("Could not write requested version");
128 }
129 if (packet_flush_gently(process->in))
130 return error("Could not write flush packet");
131
132 if (!(line = packet_read_line(process->out, NULL)) ||
133 !skip_prefix(line, welcome_prefix, &p) ||
134 strcmp(p, "-server"))
135 return error("Unexpected line '%s', expected %s-server",
136 line ? line : "<flush packet>", welcome_prefix);
137 if (!(line = packet_read_line(process->out, NULL)) ||
138 !skip_prefix(line, "version=", &p) ||
139 strtol_i(p, 10, chosen_version))
140 return error("Unexpected line '%s', expected version",
141 line ? line : "<flush packet>");
142 if ((line = packet_read_line(process->out, NULL)))
143 return error("Unexpected line '%s', expected flush", line);
144
145 /* Check to make sure that the version received is supported */
146 for (i = 0; versions[i]; i++) {
147 if (versions[i] == *chosen_version)
148 break;
149 }
150 if (!versions[i])
151 return error("Version %d not supported", *chosen_version);
152
153 return 0;
154}
155
156static int handshake_capabilities(struct child_process *process,
157 struct subprocess_capability *capabilities,
158 unsigned int *supported_capabilities)
159{
160 int i;
161 char *line;
162
163 for (i = 0; capabilities[i].name; i++) {
164 if (packet_write_fmt_gently(process->in, "capability=%s\n",
165 capabilities[i].name))
166 return error("Could not write requested capability");
167 }
168 if (packet_flush_gently(process->in))
169 return error("Could not write flush packet");
170
171 while ((line = packet_read_line(process->out, NULL))) {
172 const char *p;
173 if (!skip_prefix(line, "capability=", &p))
174 continue;
175
176 for (i = 0;
177 capabilities[i].name && strcmp(p, capabilities[i].name);
178 i++)
179 ;
180 if (capabilities[i].name) {
181 if (supported_capabilities)
182 *supported_capabilities |= capabilities[i].flag;
183 } else {
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184 warning("subprocess '%s' requested unsupported capability '%s'",
185 process->argv[0], p);
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186 }
187 }
188
189 return 0;
190}
191
192int subprocess_handshake(struct subprocess_entry *entry,
193 const char *welcome_prefix,
194 int *versions,
195 int *chosen_version,
196 struct subprocess_capability *capabilities,
197 unsigned int *supported_capabilities)
198{
199 int retval;
200 struct child_process *process = &entry->process;
201
202 sigchain_push(SIGPIPE, SIG_IGN);
203
204 retval = handshake_version(process, welcome_prefix, versions,
205 chosen_version) ||
206 handshake_capabilities(process, capabilities,
207 supported_capabilities);
208
209 sigchain_pop(SIGPIPE);
210 return retval;
211}