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d3ba566342
In handshake_capabilities() we use warning() when a capability is not supported, so the exit code of the function is 0 and no further error is shown. This is a problem because the warning message doesn't tell us which subprocess cmd failed. On the contrary if we cannot write a packet from this function, we use error() and then subprocess_start() outputs: initialization for subprocess '<cmd>' failed so we can know which subprocess cmd failed. Let's improve the warning() message, so that we can know which subprocess cmd failed. Helped-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
211 lines
5.3 KiB
C
211 lines
5.3 KiB
C
/*
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* Generic implementation of background process infrastructure.
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*/
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#include "sub-process.h"
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#include "sigchain.h"
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#include "pkt-line.h"
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int cmd2process_cmp(const void *unused_cmp_data,
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const struct subprocess_entry *e1,
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const struct subprocess_entry *e2,
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const void *unused_keydata)
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{
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return strcmp(e1->cmd, e2->cmd);
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}
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struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd)
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{
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struct subprocess_entry key;
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hashmap_entry_init(&key, strhash(cmd));
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key.cmd = cmd;
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return hashmap_get(hashmap, &key, NULL);
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}
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int subprocess_read_status(int fd, struct strbuf *status)
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{
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struct strbuf **pair;
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char *line;
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int len;
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for (;;) {
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len = packet_read_line_gently(fd, NULL, &line);
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if ((len < 0) || !line)
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break;
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pair = strbuf_split_str(line, '=', 2);
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if (pair[0] && pair[0]->len && pair[1]) {
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/* the last "status=<foo>" line wins */
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if (!strcmp(pair[0]->buf, "status=")) {
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strbuf_reset(status);
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strbuf_addbuf(status, pair[1]);
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}
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}
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strbuf_list_free(pair);
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}
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return (len < 0) ? len : 0;
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}
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void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry)
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{
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if (!entry)
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return;
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entry->process.clean_on_exit = 0;
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kill(entry->process.pid, SIGTERM);
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finish_command(&entry->process);
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hashmap_remove(hashmap, entry, NULL);
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}
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static void subprocess_exit_handler(struct child_process *process)
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{
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sigchain_push(SIGPIPE, SIG_IGN);
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/* Closing the pipe signals the subprocess to initiate a shutdown. */
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close(process->in);
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close(process->out);
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sigchain_pop(SIGPIPE);
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/* Finish command will wait until the shutdown is complete. */
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finish_command(process);
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}
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int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd,
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subprocess_start_fn startfn)
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{
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int err;
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struct child_process *process;
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const char *argv[] = { cmd, NULL };
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entry->cmd = cmd;
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process = &entry->process;
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child_process_init(process);
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process->argv = argv;
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process->use_shell = 1;
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process->in = -1;
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process->out = -1;
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process->clean_on_exit = 1;
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process->clean_on_exit_handler = subprocess_exit_handler;
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err = start_command(process);
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if (err) {
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error("cannot fork to run subprocess '%s'", cmd);
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return err;
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}
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hashmap_entry_init(entry, strhash(cmd));
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err = startfn(entry);
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if (err) {
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error("initialization for subprocess '%s' failed", cmd);
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subprocess_stop(hashmap, entry);
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return err;
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}
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hashmap_add(hashmap, entry);
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return 0;
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}
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static int handshake_version(struct child_process *process,
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const char *welcome_prefix, int *versions,
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int *chosen_version)
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{
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int version_scratch;
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int i;
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char *line;
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const char *p;
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if (!chosen_version)
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chosen_version = &version_scratch;
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if (packet_write_fmt_gently(process->in, "%s-client\n",
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welcome_prefix))
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return error("Could not write client identification");
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for (i = 0; versions[i]; i++) {
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if (packet_write_fmt_gently(process->in, "version=%d\n",
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versions[i]))
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return error("Could not write requested version");
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}
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if (packet_flush_gently(process->in))
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return error("Could not write flush packet");
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if (!(line = packet_read_line(process->out, NULL)) ||
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!skip_prefix(line, welcome_prefix, &p) ||
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strcmp(p, "-server"))
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return error("Unexpected line '%s', expected %s-server",
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line ? line : "<flush packet>", welcome_prefix);
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if (!(line = packet_read_line(process->out, NULL)) ||
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!skip_prefix(line, "version=", &p) ||
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strtol_i(p, 10, chosen_version))
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return error("Unexpected line '%s', expected version",
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line ? line : "<flush packet>");
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if ((line = packet_read_line(process->out, NULL)))
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return error("Unexpected line '%s', expected flush", line);
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/* Check to make sure that the version received is supported */
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for (i = 0; versions[i]; i++) {
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if (versions[i] == *chosen_version)
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break;
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}
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if (!versions[i])
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return error("Version %d not supported", *chosen_version);
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return 0;
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}
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static int handshake_capabilities(struct child_process *process,
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struct subprocess_capability *capabilities,
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unsigned int *supported_capabilities)
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{
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int i;
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char *line;
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for (i = 0; capabilities[i].name; i++) {
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if (packet_write_fmt_gently(process->in, "capability=%s\n",
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capabilities[i].name))
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return error("Could not write requested capability");
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}
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if (packet_flush_gently(process->in))
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return error("Could not write flush packet");
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while ((line = packet_read_line(process->out, NULL))) {
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const char *p;
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if (!skip_prefix(line, "capability=", &p))
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continue;
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for (i = 0;
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capabilities[i].name && strcmp(p, capabilities[i].name);
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i++)
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;
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if (capabilities[i].name) {
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if (supported_capabilities)
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*supported_capabilities |= capabilities[i].flag;
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} else {
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warning("subprocess '%s' requested unsupported capability '%s'",
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process->argv[0], p);
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}
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}
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return 0;
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}
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int subprocess_handshake(struct subprocess_entry *entry,
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const char *welcome_prefix,
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int *versions,
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int *chosen_version,
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struct subprocess_capability *capabilities,
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unsigned int *supported_capabilities)
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{
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int retval;
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struct child_process *process = &entry->process;
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sigchain_push(SIGPIPE, SIG_IGN);
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retval = handshake_version(process, welcome_prefix, versions,
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chosen_version) ||
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handshake_capabilities(process, capabilities,
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supported_capabilities);
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sigchain_pop(SIGPIPE);
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return retval;
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}
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