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[PATCH 3/4] refactor signal handling for cleanup functions

From
Jeff King <peff@peff.net>
Date
Jan 11, 2009, 11:36 UTC
Message-ID
<20090111113627.GC29791@coredump.intra.peff.net>
In-Reply-To
<20090111112222.GA29656@coredump.intra.peff.net>

The current code is very inconsistent about which signals are caught for doing cleanup of temporary files and lock files. Some callsites checked only SIGINT, while others checked a variety of death-dealing signals.

This patch factors out those signals to a single function, and then calls it everywhere. For some sites, that means this is a simple clean up. For others, it is an improvement in that they will now properly clean themselves up after a larger variety of signals.

Signed-off-by: Jeff King <peff@peff.net>
---
I'm assuming there was no good reason _not_ to be handling those other
signals at some of the "just handle SIGINT" sites. A sigchain
implementation which handled "remove_lock_file" without needing
"remove_lock_file_on_signal" could also call atexit(), too. So you could
have a one liner
  register_cleanup(remove_lock_file);

However, there is one case that doesn't use an atexit() handler: http-push.c. I don't know if this is a bug or an intentional omission.

 builtin-clone.c       |    2 +-
 builtin-fetch--tool.c |    2 +-
 builtin-fetch.c       |    2 +-
 diff.c                |    2 +-
 http-push.c           |    5 +----
 lockfile.c            |    6 +-----
 sigchain.c            |    9 +++++++++
 sigchain.h            |    2 ++
 8 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/builtin-clone.c b/builtin-clone.c
index 18b9392..44c8073 100644
--- a/builtin-clone.c
+++ b/builtin-clone.c
@@ -439,7 +439,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	}
 	junk_git_dir = git_dir;
 	atexit(remove_junk);
-	sigchain_push(SIGINT, remove_junk_on_signal);
+	sigchain_push_common(remove_junk_on_signal);
 
 	setenv(CONFIG_ENVIRONMENT, xstrdup(mkpath("%s/config", git_dir)), 1);
 
diff --git a/builtin-fetch--tool.c b/builtin-fetch--tool.c
index b1d7f8f..29356d2 100644
--- a/builtin-fetch--tool.c
+++ b/builtin-fetch--tool.c
@@ -246,7 +246,7 @@ static int fetch_native_store(FILE *fp,
 	char buffer[1024];
 	int err = 0;
 
-	sigchain_push(SIGINT, remove_keep_on_signal);
+	sigchain_push_common(remove_keep_on_signal);
 	atexit(remove_keep);
 
 	while (fgets(buffer, sizeof(buffer), stdin)) {
diff --git a/builtin-fetch.c b/builtin-fetch.c
index 8c86974..1e4a3d9 100644
--- a/builtin-fetch.c
+++ b/builtin-fetch.c
@@ -673,7 +673,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 		ref_nr = j;
 	}
 
-	sigchain_push(SIGINT, unlock_pack_on_signal);
+	sigchain_push_common(unlock_pack_on_signal);
 	atexit(unlock_pack);
 	exit_code = do_fetch(transport,
 			parse_fetch_refspec(ref_nr, refs), ref_nr);
diff --git a/diff.c b/diff.c
index 5a74012..7fc8512 100644
--- a/diff.c
+++ b/diff.c
@@ -1969,7 +1969,7 @@ static void run_external_diff(const char *pgm,
 			atexit_asked = 1;
 			atexit(remove_tempfile);
 		}
-		sigchain_push(SIGINT, remove_tempfile_on_signal);
+		sigchain_push_common(remove_tempfile_on_signal);
 	}
 
 	if (one && two) {
diff --git a/http-push.c b/http-push.c
index dec395d..7d5c23e 100644
--- a/http-push.c
+++ b/http-push.c
@@ -2262,10 +2262,7 @@ int main(int argc, char **argv)
 		goto cleanup;
 	}
 
-	sigchain_push(SIGINT, remove_locks_on_signal);
-	sigchain_push(SIGHUP, remove_locks_on_signal);
-	sigchain_push(SIGQUIT, remove_locks_on_signal);
-	sigchain_push(SIGTERM, remove_locks_on_signal);
+	sigchain_push_common(remove_locks_on_signal);
 
 	/* Check whether the remote has server info files */
 	remote->can_update_info_refs = 0;
diff --git a/lockfile.c b/lockfile.c
index 3cd57dc..021c337 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -137,11 +137,7 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
 	lk->fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
 	if (0 <= lk->fd) {
 		if (!lock_file_list) {
-			sigchain_push(SIGINT, remove_lock_file_on_signal);
-			sigchain_push(SIGHUP, remove_lock_file_on_signal);
-			sigchain_push(SIGTERM, remove_lock_file_on_signal);
-			sigchain_push(SIGQUIT, remove_lock_file_on_signal);
-			sigchain_push(SIGPIPE, remove_lock_file_on_signal);
+			sigchain_push_common(remove_lock_file_on_signal);
 			atexit(remove_lock_file);
 		}
 		lk->owner = getpid();
diff --git a/sigchain.c b/sigchain.c
index a18d505..1118b99 100644
--- a/sigchain.c
+++ b/sigchain.c
@@ -41,3 +41,12 @@ int sigchain_pop(int sig)
 	s->n--;
 	return 0;
 }
+
+void sigchain_push_common(sigchain_fun f)
+{
+	sigchain_push(SIGINT, f);
+	sigchain_push(SIGHUP, f);
+	sigchain_push(SIGTERM, f);
+	sigchain_push(SIGQUIT, f);
+	sigchain_push(SIGPIPE, f);
+}
diff --git a/sigchain.h b/sigchain.h
index 254ebb0..618083b 100644
--- a/sigchain.h
+++ b/sigchain.h
@@ -6,4 +6,6 @@ typedef void (*sigchain_fun)(int);
 int sigchain_push(int sig, sigchain_fun f);
 int sigchain_pop(int sig);
 
+void sigchain_push_common(sigchain_fun f);
+
 #endif /* SIGCHAIN_H */

-- 
1.6.1.84.g8150
Previous: Jeff KingNext: Jeff King
Message 14 of 41 in “Funny: git -p submodule summary”
  1. Johannes SchindelinJan 8, 2009
  2. Johannes SchindelinJan 8, 2009
  3. Jeff KingJan 9, 2009
  4. Jeff KingJan 9, 2009
  5. Jeff KingJan 9, 2009
  6. Johannes SixtJan 9, 2009
  7. Jeff KingJan 9, 2009
  8. Johannes SixtJan 9, 2009
  9. Jeff KingJan 9, 2009
  10. Jeff KingJan 11, 2009
  11. 1/4 Makefile: clean up TEST_PROGRAMS definitionJeff King, Jan 11, 2009
  12. 2/4 chain kill signals for cleanup functionsJeff King, Jan 11, 2009
  13. Jeff KingJan 11, 2009
  14. 3/4 refactor signal handling for cleanup functionsJeff King, Jan 11, 2009
  15. 4/4 pager: do wait_for_pager on signal deathJeff King, Jan 11, 2009
  16. Junio C HamanoJan 11, 2009
  17. Johannes SixtJan 12, 2009
  18. Jeff KingJan 12, 2009
  19. Johannes SixtJan 12, 2009
  20. Jeff KingJan 12, 2009
  21. Johannes SixtJan 12, 2009
  22. Junio C HamanoJan 9, 2009
  23. Jeff KingJan 9, 2009
  24. Junio C HamanoJan 9, 2009
  25. 0/3 fix "Funny: git -p submodule summary"Jeff King, Jan 27, 2009
  26. 1/3 git: s/run_command/run_builtin/Jeff King, Jan 27, 2009
  27. 2/3 run_command: handle missing command errors more gracefullyJeff King, Jan 27, 2009
  28. 3/3 git: use run_command to execute dashed externalsJeff King, Jan 27, 2009
  29. Johannes SixtJan 27, 2009
  30. Jeff KingJan 27, 2009
  31. Johannes SixtJan 27, 2009
  32. Jeff KingJan 28, 2009
  33. Johannes SchindelinJan 27, 2009
  34. Jeff KingJan 28, 2009
  35. 1/4 git: s/run_command/run_builtin/Jeff King, Jan 28, 2009
  36. 2/4 run_command: handle missing command errors more gracefullyJeff King, Jan 28, 2009
  37. 3/4 run-command: help callers distinguish errorsJeff King, Jan 28, 2009
  38. Jeff KingJan 28, 2009
  39. Jeff KingJan 28, 2009
  40. 4/4 git: use run_command to execute dashed externalsJeff King, Jan 28, 2009
  41. Junio C HamanoJan 28, 2009

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