common-main.c

   1 #include "cache.h"
   2 #include "exec-cmd.h"
   3 #include "gettext.h"
   4 #include "attr.h"
   5 #include "setup.h"
   6
   7 /*
   8  * Many parts of Git have subprograms communicate via pipe, expect the
   9  * upstream of a pipe to die with SIGPIPE when the downstream of a
  10  * pipe does not need to read all that is written.  Some third-party
  11  * programs that ignore or block SIGPIPE for their own reason forget
  12  * to restore SIGPIPE handling to the default before spawning Git and
  13  * break this carefully orchestrated machinery.
  14  *
  15  * Restore the way SIGPIPE is handled to default, which is what we
  16  * expect.
  17  */
  18 static void restore_sigpipe_to_default(void)
  19 {
  20         sigset_t unblock;
  21
  22         sigemptyset(&unblock);
  23         sigaddset(&unblock, SIGPIPE);
  24         sigprocmask(SIG_UNBLOCK, &unblock, NULL);
  25         signal(SIGPIPE, SIG_DFL);
  26 }
  27
  28 int main(int argc, const char **argv)
  29 {
  30         int result;
  31         struct strbuf tmp = STRBUF_INIT;
  32
  33         trace2_initialize_clock();
  34
  35         /*
  36          * Always open file descriptors 0/1/2 to avoid clobbering files
  37          * in die().  It also avoids messing up when the pipes are dup'ed
  38          * onto stdin/stdout/stderr in the child processes we spawn.
  39          */
  40         sanitize_stdfds();
  41         restore_sigpipe_to_default();
  42
  43         git_resolve_executable_dir(argv[0]);
  44
  45         setlocale(LC_CTYPE, "");
  46         git_setup_gettext();
  47
  48         initialize_the_repository();
  49
  50         attr_start();
  51
  52         trace2_initialize();
  53         trace2_cmd_start(argv);
  54         trace2_collect_process_info(TRACE2_PROCESS_INFO_STARTUP);
  55
  56         if (!strbuf_getcwd(&tmp))
  57                 tmp_original_cwd = strbuf_detach(&tmp, NULL);
  58
  59         result = cmd_main(argc, argv);
  60
  61         /* Not exit(3), but a wrapper calling our common_exit() */
  62         exit(result);
  63 }
  64
  65 static void check_bug_if_BUG(void)
  66 {
  67         if (!bug_called_must_BUG)
  68                 return;
  69         BUG("on exit(): had bug() call(s) in this process without explicit BUG_if_bug()");
  70 }
  71
  72 /* We wrap exit() to call common_exit() in git-compat-util.h */
  73 int common_exit(const char *file, int line, int code)
  74 {
  75         /*
  76          * For non-POSIX systems: Take the lowest 8 bits of the "code"
  77          * to e.g. turn -1 into 255. On a POSIX system this is
  78          * redundant, see exit(3) and wait(2), but as it doesn't harm
  79          * anything there we don't need to guard this with an "ifdef".
  80          */
  81         code &= 0xff;
  82
  83         check_bug_if_BUG();
  84         trace2_cmd_exit_fl(file, line, code);
  85
  86         return code;
  87 }