0cc05b044f
Add a bug() function to use in cases where we'd like to indicate a
runtime BUG(), but would like to defer the BUG() call because we're
possibly accumulating more bug() callers to exhaustively indicate what
went wrong.
We already have this sort of facility in various parts of the
codebase, just in the form of ad-hoc re-inventions of the
functionality that this new API provides. E.g. this will be used to
replace optbug() in parse-options.c, and the 'error("BUG:[...]' we do
in a loop in builtin/receive-pack.c.
Unlike the code this replaces we'll log to trace2 with this new bug()
function (as with other usage.c functions, including BUG()), we'll
also be able to avoid calls to xstrfmt() in some cases, as the bug()
function itself accepts variadic sprintf()-like arguments.
Any caller to bug() can follow up such calls with BUG_if_bug(),
which will BUG() out (i.e. abort()) if there were any preceding calls
to bug(), callers can also decide not to call BUG_if_bug() and leave
the resulting BUG() invocation until exit() time. There are currently
no bug() API users that don't call BUG_if_bug() themselves after a
for-loop, but allowing for not calling BUG_if_bug() keeps the API
flexible. As the tests and documentation here show we'll catch missing
BUG_if_bug() invocations in our exit() wrapper.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
85 lines
2.1 KiB
C
85 lines
2.1 KiB
C
#include "cache.h"
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#include "exec-cmd.h"
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#include "attr.h"
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/*
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* Many parts of Git have subprograms communicate via pipe, expect the
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* upstream of a pipe to die with SIGPIPE when the downstream of a
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* pipe does not need to read all that is written. Some third-party
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* programs that ignore or block SIGPIPE for their own reason forget
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* to restore SIGPIPE handling to the default before spawning Git and
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* break this carefully orchestrated machinery.
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*
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* Restore the way SIGPIPE is handled to default, which is what we
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* expect.
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*/
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static void restore_sigpipe_to_default(void)
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{
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sigset_t unblock;
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sigemptyset(&unblock);
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sigaddset(&unblock, SIGPIPE);
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sigprocmask(SIG_UNBLOCK, &unblock, NULL);
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signal(SIGPIPE, SIG_DFL);
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}
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int main(int argc, const char **argv)
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{
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int result;
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struct strbuf tmp = STRBUF_INIT;
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trace2_initialize_clock();
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/*
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* Always open file descriptors 0/1/2 to avoid clobbering files
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* in die(). It also avoids messing up when the pipes are dup'ed
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* onto stdin/stdout/stderr in the child processes we spawn.
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*/
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sanitize_stdfds();
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restore_sigpipe_to_default();
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git_resolve_executable_dir(argv[0]);
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git_setup_gettext();
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initialize_the_repository();
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attr_start();
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trace2_initialize();
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trace2_cmd_start(argv);
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trace2_collect_process_info(TRACE2_PROCESS_INFO_STARTUP);
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if (!strbuf_getcwd(&tmp))
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tmp_original_cwd = strbuf_detach(&tmp, NULL);
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result = cmd_main(argc, argv);
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/* Not exit(3), but a wrapper calling our common_exit() */
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exit(result);
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}
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static void check_bug_if_BUG(void)
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{
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if (!bug_called_must_BUG)
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return;
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BUG("on exit(): had bug() call(s) in this process without explicit BUG_if_bug()");
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}
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/* We wrap exit() to call common_exit() in git-compat-util.h */
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int common_exit(const char *file, int line, int code)
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{
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/*
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* For non-POSIX systems: Take the lowest 8 bits of the "code"
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* to e.g. turn -1 into 255. On a POSIX system this is
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* redundant, see exit(3) and wait(2), but as it doesn't harm
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* anything there we don't need to guard this with an "ifdef".
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*/
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code &= 0xff;
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check_bug_if_BUG();
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trace2_cmd_exit_fl(file, line, code);
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return code;
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}
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