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/*
* Generic implementation of background process infrastructure.
*/
#include "sub-process.h"
#include "sigchain.h"
#include "pkt-line.h"
int cmd2process_cmp(const void *unused_cmp_data,
const void *entry,
const void *entry_or_key,
const void *unused_keydata)
{
const struct subprocess_entry *e1 = entry;
const struct subprocess_entry *e2 = entry_or_key;
return strcmp(e1->cmd, e2->cmd);
}
struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd)
{
struct subprocess_entry key;
hashmap_entry_init(&key, strhash(cmd));
key.cmd = cmd;
return hashmap_get(hashmap, &key, NULL);
}
int subprocess_read_status(int fd, struct strbuf *status)
{
struct strbuf **pair;
char *line;
int len;
for (;;) {
len = packet_read_line_gently(fd, NULL, &line);
if ((len < 0) || !line)
break;
pair = strbuf_split_str(line, '=', 2);
if (pair[0] && pair[0]->len && pair[1]) {
/* the last "status=<foo>" line wins */
if (!strcmp(pair[0]->buf, "status=")) {
strbuf_reset(status);
strbuf_addbuf(status, pair[1]);
}
}
strbuf_list_free(pair);
}
return (len < 0) ? len : 0;
}
void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry)
{
if (!entry)
return;
entry->process.clean_on_exit = 0;
kill(entry->process.pid, SIGTERM);
finish_command(&entry->process);
hashmap_remove(hashmap, entry, NULL);
}
static void subprocess_exit_handler(struct child_process *process)
{
sigchain_push(SIGPIPE, SIG_IGN);
/* Closing the pipe signals the subprocess to initiate a shutdown. */
close(process->in);
close(process->out);
sigchain_pop(SIGPIPE);
/* Finish command will wait until the shutdown is complete. */
finish_command(process);
}
int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd,
subprocess_start_fn startfn)
{
int err;
struct child_process *process;
entry->cmd = cmd;
process = &entry->process;
child_process_init(process);
argv_array_push(&process->args, cmd);
process->use_shell = 1;
process->in = -1;
process->out = -1;
process->clean_on_exit = 1;
process->clean_on_exit_handler = subprocess_exit_handler;
err = start_command(process);
if (err) {
error("cannot fork to run subprocess '%s'", cmd);
return err;
}
hashmap_entry_init(entry, strhash(cmd));
err = startfn(entry);
if (err) {
error("initialization for subprocess '%s' failed", cmd);
subprocess_stop(hashmap, entry);
return err;
}
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 {
die("subprocess '%s' requested unsupported capability '%s'",
process->argv[0], 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;
}
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