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