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-rw-r--r--sub-process.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/sub-process.c b/sub-process.c
index a3cfab1a9..86de8d7bf 100644
--- a/sub-process.c
+++ b/sub-process.c
@@ -105,3 +105,107 @@ int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, co
hashmap_add(hashmap, entry);
return 0;
}
+
+static int handshake_version(struct child_process *process,
+ const char *welcome_prefix, int *versions,
+ int *chosen_version)
+{
+ int version_scratch;
+ int i;
+ char *line;
+ const char *p;
+
+ if (!chosen_version)
+ chosen_version = &version_scratch;
+
+ if (packet_write_fmt_gently(process->in, "%s-client\n",
+ welcome_prefix))
+ return error("Could not write client identification");
+ for (i = 0; versions[i]; i++) {
+ if (packet_write_fmt_gently(process->in, "version=%d\n",
+ versions[i]))
+ return error("Could not write requested version");
+ }
+ if (packet_flush_gently(process->in))
+ return error("Could not write flush packet");
+
+ if (!(line = packet_read_line(process->out, NULL)) ||
+ !skip_prefix(line, welcome_prefix, &p) ||
+ strcmp(p, "-server"))
+ return error("Unexpected line '%s', expected %s-server",
+ line ? line : "<flush packet>", welcome_prefix);
+ if (!(line = packet_read_line(process->out, NULL)) ||
+ !skip_prefix(line, "version=", &p) ||
+ strtol_i(p, 10, chosen_version))
+ return error("Unexpected line '%s', expected version",
+ line ? line : "<flush packet>");
+ if ((line = packet_read_line(process->out, NULL)))
+ return error("Unexpected line '%s', expected flush", line);
+
+ /* Check to make sure that the version received is supported */
+ for (i = 0; versions[i]; i++) {
+ if (versions[i] == *chosen_version)
+ break;
+ }
+ if (!versions[i])
+ return error("Version %d not supported", *chosen_version);
+
+ return 0;
+}
+
+static int handshake_capabilities(struct child_process *process,
+ struct subprocess_capability *capabilities,
+ unsigned int *supported_capabilities)
+{
+ int i;
+ char *line;
+
+ for (i = 0; capabilities[i].name; i++) {
+ if (packet_write_fmt_gently(process->in, "capability=%s\n",
+ capabilities[i].name))
+ return error("Could not write requested capability");
+ }
+ if (packet_flush_gently(process->in))
+ return error("Could not write flush packet");
+
+ while ((line = packet_read_line(process->out, NULL))) {
+ const char *p;
+ if (!skip_prefix(line, "capability=", &p))
+ continue;
+
+ for (i = 0;
+ capabilities[i].name && strcmp(p, capabilities[i].name);
+ i++)
+ ;
+ if (capabilities[i].name) {
+ if (supported_capabilities)
+ *supported_capabilities |= capabilities[i].flag;
+ } else {
+ warning("external filter requested unsupported filter capability '%s'",
+ p);
+ }
+ }
+
+ return 0;
+}
+
+int subprocess_handshake(struct subprocess_entry *entry,
+ const char *welcome_prefix,
+ int *versions,
+ int *chosen_version,
+ struct subprocess_capability *capabilities,
+ unsigned int *supported_capabilities)
+{
+ int retval;
+ struct child_process *process = &entry->process;
+
+ sigchain_push(SIGPIPE, SIG_IGN);
+
+ retval = handshake_version(process, welcome_prefix, versions,
+ chosen_version) ||
+ handshake_capabilities(process, capabilities,
+ supported_capabilities);
+
+ sigchain_pop(SIGPIPE);
+ return retval;
+}