common-main.c

   1 #include "cache.h"
   2 #include "exec-cmd.h"
   3 #include "gettext.h"
   4 #include "attr.h"
   5
   6 /*
   7  * Many parts of Git have subprograms communicate via pipe, expect the
   8  * upstream of a pipe to die with SIGPIPE when the downstream of a
   9  * pipe does not need to read all that is written.  Some third-party
  10  * programs that ignore or block SIGPIPE for their own reason forget
  11  * to restore SIGPIPE handling to the default before spawning Git and
  12  * break this carefully orchestrated machinery.
  13  *
  14  * Restore the way SIGPIPE is handled to default, which is what we
  15  * expect.
  16  */
  17 static void restore_sigpipe_to_default(void)
  18 {
  19         sigset_t unblock;
  20
  21         sigemptyset(&unblock);
  22         sigaddset(&unblock, SIGPIPE);
  23         sigprocmask(SIG_UNBLOCK, &unblock, NULL);
  24         signal(SIGPIPE, SIG_DFL);
  25 }
  26
  27 int main(int argc, const char **argv)
  28 {
  29         int result;
  30         struct strbuf tmp = STRBUF_INIT;
  31
  32         trace2_initialize_clock();
  33
  34         /*
  35          * Always open file descriptors 0/1/2 to avoid clobbering files
  36          * in die().  It also avoids messing up when the pipes are dup'ed
  37          * onto stdin/stdout/stderr in the child processes we spawn.
  38          */
  39         sanitize_stdfds();
  40         restore_sigpipe_to_default();
  41
  42         git_resolve_executable_dir(argv[0]);
  43
  44         setlocale(LC_CTYPE, "");
  45         git_setup_gettext();
  46
  47         initialize_the_repository();
  48
  49         attr_start();
  50
  51         trace2_initialize();
  52         trace2_cmd_start(argv);
  53         trace2_collect_process_info(TRACE2_PROCESS_INFO_STARTUP);
  54
  55         if (!strbuf_getcwd(&tmp))
  56                 tmp_original_cwd = strbuf_detach(&tmp, NULL);
  57
  58         result = cmd_main(argc, argv);
  59
  60         /* Not exit(3), but a wrapper calling our common_exit() */
  61         exit(result);
  62 }
  63
  64 static void check_bug_if_BUG(void)
  65 {
  66         if (!bug_called_must_BUG)
  67                 return;
  68         BUG("on exit(): had bug() call(s) in this process without explicit BUG_if_bug()");
  69 }
  70
  71 /* We wrap exit() to call common_exit() in git-compat-util.h */
  72 int common_exit(const char *file, int line, int code)
  73 {
  74         /*
  75          * For non-POSIX systems: Take the lowest 8 bits of the "code"
  76          * to e.g. turn -1 into 255. On a POSIX system this is
  77          * redundant, see exit(3) and wait(2), but as it doesn't harm
  78          * anything there we don't need to guard this with an "ifdef".
  79          */
  80         code &= 0xff;
  81
  82         check_bug_if_BUG();
  83         trace2_cmd_exit_fl(file, line, code);
  84
  85         return code;
  86 }