sub-process.c

   1 /*
   2  * Generic implementation of background process infrastructure.
   3  */
   4 #include "sub-process.h"
   5 #include "sigchain.h"
   6 #include "pkt-line.h"
   7
   8 int cmd2process_cmp(const struct subprocess_entry *e1,
   9                            const struct subprocess_entry *e2,
  10                            const void *unused)
  11 {
  12         return strcmp(e1->cmd, e2->cmd);
  13 }
  14
  15 struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd)
  16 {
  17         struct subprocess_entry key;
  18
  19         hashmap_entry_init(&key, strhash(cmd));
  20         key.cmd = cmd;
  21         return hashmap_get(hashmap, &key, NULL);
  22 }
  23
  24 int subprocess_read_status(int fd, struct strbuf *status)
  25 {
  26         struct strbuf **pair;
  27         char *line;
  28         int len;
  29
  30         for (;;) {
  31                 len = packet_read_line_gently(fd, NULL, &line);
  32                 if ((len < 0) || !line)
  33                         break;
  34                 pair = strbuf_split_str(line, '=', 2);
  35                 if (pair[0] && pair[0]->len && pair[1]) {
  36                         /* the last "status=<foo>" line wins */
  37                         if (!strcmp(pair[0]->buf, "status=")) {
  38                                 strbuf_reset(status);
  39                                 strbuf_addbuf(status, pair[1]);
  40                         }
  41                 }
  42                 strbuf_list_free(pair);
  43         }
  44
  45         return (len < 0) ? len : 0;
  46 }
  47
  48 void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry)
  49 {
  50         if (!entry)
  51                 return;
  52
  53         entry->process.clean_on_exit = 0;
  54         kill(entry->process.pid, SIGTERM);
  55         finish_command(&entry->process);
  56
  57         hashmap_remove(hashmap, entry, NULL);
  58 }
  59
  60 static void subprocess_exit_handler(struct child_process *process)
  61 {
  62         sigchain_push(SIGPIPE, SIG_IGN);
  63         /* Closing the pipe signals the subprocess to initiate a shutdown. */
  64         close(process->in);
  65         close(process->out);
  66         sigchain_pop(SIGPIPE);
  67         /* Finish command will wait until the shutdown is complete. */
  68         finish_command(process);
  69 }
  70
  71 int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd,
  72         subprocess_start_fn startfn)
  73 {
  74         int err;
  75         struct child_process *process;
  76         const char *argv[] = { cmd, NULL };
  77
  78         entry->cmd = cmd;
  79         process = &entry->process;
  80
  81         child_process_init(process);
  82         process->argv = argv;
  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;
  88
  89         err = start_command(process);
  90         if (err) {
  91                 error("cannot fork to run subprocess '%s'", cmd);
  92                 return err;
  93         }
  94
  95         hashmap_entry_init(entry, strhash(cmd));
  96
  97         err = startfn(entry);
  98         if (err) {
  99                 error("initialization for subprocess '%s' failed", cmd);
 100                 subprocess_stop(hashmap, entry);
 101                 return err;
 102         }
 103
 104         hashmap_add(hashmap, entry);
 105         return 0;
 106 }