common-main.c

   1 #include "git-compat-util.h"
   2 #include "exec-cmd.h"
   3 #include "gettext.h"
   4 #include "attr.h"
   5 #include "repository.h"
   6 #include "setup.h"
   7 #include "strbuf.h"
   8 #include "trace2.h"
   9
  10 /*
  11  * Many parts of Git have subprograms communicate via pipe, expect the
  12  * upstream of a pipe to die with SIGPIPE when the downstream of a
  13  * pipe does not need to read all that is written.  Some third-party
  14  * programs that ignore or block SIGPIPE for their own reason forget
  15  * to restore SIGPIPE handling to the default before spawning Git and
  16  * break this carefully orchestrated machinery.
  17  *
  18  * Restore the way SIGPIPE is handled to default, which is what we
  19  * expect.
  20  */
  21 static void restore_sigpipe_to_default(void)
  22 {
  23         sigset_t unblock;
  24
  25         sigemptyset(&unblock);
  26         sigaddset(&unblock, SIGPIPE);
  27         sigprocmask(SIG_UNBLOCK, &unblock, NULL);
  28         signal(SIGPIPE, SIG_DFL);
  29 }
  30
  31 int main(int argc, const char **argv)
  32 {
  33         int result;
  34         struct strbuf tmp = STRBUF_INIT;
  35
  36         trace2_initialize_clock();
  37
  38         /*
  39          * Always open file descriptors 0/1/2 to avoid clobbering files
  40          * in die().  It also avoids messing up when the pipes are dup'ed
  41          * onto stdin/stdout/stderr in the child processes we spawn.
  42          */
  43         sanitize_stdfds();
  44         restore_sigpipe_to_default();
  45
  46         git_resolve_executable_dir(argv[0]);
  47
  48         setlocale(LC_CTYPE, "");
  49         git_setup_gettext();
  50
  51         initialize_repository(the_repository);
  52
  53         attr_start();
  54
  55         trace2_initialize();
  56         trace2_cmd_start(argv);
  57         trace2_collect_process_info(TRACE2_PROCESS_INFO_STARTUP);
  58
  59         if (!strbuf_getcwd(&tmp))
  60                 tmp_original_cwd = strbuf_detach(&tmp, NULL);
  61
  62         result = cmd_main(argc, argv);
  63
  64         /* Not exit(3), but a wrapper calling our common_exit() */
  65         exit(result);
  66 }
  67
  68 static void check_bug_if_BUG(void)
  69 {
  70         if (!bug_called_must_BUG)
  71                 return;
  72         BUG("on exit(): had bug() call(s) in this process without explicit BUG_if_bug()");
  73 }
  74
  75 /* We wrap exit() to call common_exit() in git-compat-util.h */
  76 int common_exit(const char *file, int line, int code)
  77 {
  78         /*
  79          * For non-POSIX systems: Take the lowest 8 bits of the "code"
  80          * to e.g. turn -1 into 255. On a POSIX system this is
  81          * redundant, see exit(3) and wait(2), but as it doesn't harm
  82          * anything there we don't need to guard this with an "ifdef".
  83          */
  84         code &= 0xff;
  85
  86         check_bug_if_BUG();
  87         trace2_cmd_exit_fl(file, line, code);
  88
  89         return code;
  90 }