common-main.c

   1 #include "cache.h"
   2 #include "exec-cmd.h"
   3 #include "attr.h"
   4
   5 /*
   6  * Many parts of Git have subprograms communicate via pipe, expect the
   7  * upstream of a pipe to die with SIGPIPE when the downstream of a
   8  * pipe does not need to read all that is written.  Some third-party
   9  * programs that ignore or block SIGPIPE for their own reason forget
  10  * to restore SIGPIPE handling to the default before spawning Git and
  11  * break this carefully orchestrated machinery.
  12  *
  13  * Restore the way SIGPIPE is handled to default, which is what we
  14  * expect.
  15  */
  16 static void restore_sigpipe_to_default(void)
  17 {
  18         sigset_t unblock;
  19
  20         sigemptyset(&unblock);
  21         sigaddset(&unblock, SIGPIPE);
  22         sigprocmask(SIG_UNBLOCK, &unblock, NULL);
  23         signal(SIGPIPE, SIG_DFL);
  24 }
  25
  26 int main(int argc, const char **argv)
  27 {
  28         int result;
  29         struct strbuf tmp = STRBUF_INIT;
  30
  31         trace2_initialize_clock();
  32
  33         /*
  34          * Always open file descriptors 0/1/2 to avoid clobbering files
  35          * in die().  It also avoids messing up when the pipes are dup'ed
  36          * onto stdin/stdout/stderr in the child processes we spawn.
  37          */
  38         sanitize_stdfds();
  39         restore_sigpipe_to_default();
  40
  41         git_resolve_executable_dir(argv[0]);
  42
  43         git_setup_gettext();
  44
  45         initialize_the_repository();
  46
  47         attr_start();
  48
  49         trace2_initialize();
  50         trace2_cmd_start(argv);
  51         trace2_collect_process_info(TRACE2_PROCESS_INFO_STARTUP);
  52
  53         if (!strbuf_getcwd(&tmp))
  54                 tmp_original_cwd = strbuf_detach(&tmp, NULL);
  55
  56         result = cmd_main(argc, argv);
  57
  58         /* Not exit(3), but a wrapper calling our common_exit() */
  59         exit(result);
  60 }
  61
  62 static void check_bug_if_BUG(void)
  63 {
  64         if (!bug_called_must_BUG)
  65                 return;
  66         BUG("on exit(): had bug() call(s) in this process without explicit BUG_if_bug()");
  67 }
  68
  69 /* We wrap exit() to call common_exit() in git-compat-util.h */
  70 int common_exit(const char *file, int line, int code)
  71 {
  72         /*
  73          * For non-POSIX systems: Take the lowest 8 bits of the "code"
  74          * to e.g. turn -1 into 255. On a POSIX system this is
  75          * redundant, see exit(3) and wait(2), but as it doesn't harm
  76          * anything there we don't need to guard this with an "ifdef".
  77          */
  78         code &= 0xff;
  79
  80         check_bug_if_BUG();
  81         trace2_cmd_exit_fl(file, line, code);
  82
  83         return code;
  84 }