@matheusbsbs / matheus-bagliano / commits / 19d75948ef

common-main.c: move non-trace2 exit() behavior out of trace2.c

Change the exit() wrapper added in ee4512ed481 (trace2: create new combined trace facility, 2019-02-22) so that we'll split up the trace2 logging concerns from wanting to wrap the "exit()" function itself for other purposes. This makes more sense structurally, as we won't seem to conflate non-trace2 behavior with the trace2 code. I'd previously added an explanation for this in 368b5843158 (common-main.c: call exit(), don't return, 2021-12-07), that comment is being adjusted here. Now the only thing we'll do if we're not using trace2 is to truncate the "code" argument to the lowest 8 bits. We only need to do that truncation on non-POSIX systems, but in ee4512ed481 that "if defined(__MINGW32__)" code added in 47e3de0e796 (MinGW: truncate exit()'s argument to lowest 8 bits, 2009-07-05) was made to run everywhere. It might be good for clarify to narrow that down by an "ifdef" again, but I'm not certain that in the interim we haven't had some other non-POSIX systems rely the behavior. On a POSIX system taking the lowest 8 bits is implicit, see exit(3)[1] and wait(2)[2]. Let's leave a comment about that instead. 1. https://man7.org/linux/man-pages/man3/exit.3.html 2. https://man7.org/linux/man-pages/man2/wait.2.html Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Ævar Arnfjörð Bjarmason committed Jun 2, 2022 at 14:25 UTC 19d75948ef7abe9066efa4462108827d70565ae9
4 files changed +21 -19
common-main.c
+16 -4
@@ -55,10 +55,22 @@ int main(int argc, const char **argv)
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 +/* We wrap exit() to call common_exit() in git-compat-util.h */
63 +int common_exit(const char *file, int line, int code)
64 +{
65 /*
59 - * We define exit() to call trace2_cmd_exit_fl() in
60 - * git-compat-util.h. Whether we reach this or exit()
61 - * elsewhere we'll always run our trace2 exit handler.
66 + * For non-POSIX systems: Take the lowest 8 bits of the "code"
67 + * to e.g. turn -1 into 255. On a POSIX system this is
68 + * redundant, see exit(3) and wait(2), but as it doesn't harm
69 + * anything there we don't need to guard this with an "ifdef".
70 */
63 - exit(result);
71 + code &= 0xff;
72 +
73 + trace2_cmd_exit_fl(file, line, code);
74 +
75 + return code;
76 }
git-compat-util.h
+2 -2
@@ -1451,8 +1451,8 @@ int cmd_main(int, const char **);
1451 * Intercept all calls to exit() and route them to trace2 to
1452 * optionally emit a message before calling the real exit().
1453 */
1454 -int trace2_cmd_exit_fl(const char *file, int line, int code);
1455 -#define exit(code) exit(trace2_cmd_exit_fl(__FILE__, __LINE__, (code)))
1454 +int common_exit(const char *file, int line, int code);
1455 +#define exit(code) exit(common_exit(__FILE__, __LINE__, (code)))
1456
1457 /*
1458 * You can mark a stack variable with UNLEAK(var) to avoid it being
trace2.c
+2 -6
@@ -202,17 +202,15 @@ void trace2_cmd_start_fl(const char *file, int line, const char **argv)
202 argv);
203 }
204
205 -int trace2_cmd_exit_fl(const char *file, int line, int code)
205 +void trace2_cmd_exit_fl(const char *file, int line, int code)
206 {
207 struct tr2_tgt *tgt_j;
208 int j;
209 uint64_t us_now;
210 uint64_t us_elapsed_absolute;
211
212 - code &= 0xff;
213 -
212 if (!trace2_enabled)
215 - return code;
213 + return;
214
215 trace_git_fsync_stats();
216 trace2_collect_process_info(TRACE2_PROCESS_INFO_EXIT);
@@ -226,8 +224,6 @@ int trace2_cmd_exit_fl(const char *file, int line, int code)
224 if (tgt_j->pfn_exit_fl)
225 tgt_j->pfn_exit_fl(file, line, us_elapsed_absolute,
226 code);
229 -
230 - return code;
227 }
228
229 void trace2_cmd_error_va_fl(const char *file, int line, const char *fmt,
trace2.h
+1 -7
@@ -101,14 +101,8 @@ void trace2_cmd_start_fl(const char *file, int line, const char **argv);
101
102 /*
103 * Emit an 'exit' event.
104 - *
105 - * Write the exit-code that will be passed to exit() or returned
106 - * from main().
107 - *
108 - * Use this prior to actually calling exit().
109 - * See "#define exit()" in git-compat-util.h
104 */
111 -int trace2_cmd_exit_fl(const char *file, int line, int code);
105 +void trace2_cmd_exit_fl(const char *file, int line, int code);
106
107 #define trace2_cmd_exit(code) (trace2_cmd_exit_fl(__FILE__, __LINE__, (code)))
108