Merge branch 'jk/signal-cleanup'

* jk/signal-cleanup:
  t0005: use SIGTERM for sigchain test
  pager: do wait_for_pager on signal death
  refactor signal handling for cleanup functions
  chain kill signals for cleanup functions
  diff: refactor tempfile cleanup handling
  Windows: Fix signal numbers

.gitignore

@@ -153,6 +153,7 @@ test-match-trees
 test-parse-options
 test-path-utils
 test-sha1
+test-sigchain
 common-cmds.h
 *.tar.gz
 *.dsc

Makefile

@@ -391,6 +391,7 @@ LIB_H += revision.h
 LIB_H += run-command.h
 LIB_H += sha1-lookup.h
 LIB_H += sideband.h
+LIB_H += sigchain.h
 LIB_H += strbuf.h
 LIB_H += tag.h
 LIB_H += transport.h
@@ -484,6 +485,7 @@ LIB_OBJS += sha1-lookup.o
 LIB_OBJS += sha1_name.o
 LIB_OBJS += shallow.o
 LIB_OBJS += sideband.o
+LIB_OBJS += sigchain.o
 LIB_OBJS += strbuf.o
 LIB_OBJS += symlinks.o
 LIB_OBJS += tag.o
@@ -1374,6 +1376,7 @@ TEST_PROGRAMS += test-match-trees$X
 TEST_PROGRAMS += test-parse-options$X
 TEST_PROGRAMS += test-path-utils$X
 TEST_PROGRAMS += test-sha1$X
+TEST_PROGRAMS += test-sigchain$X
 
 all:: $(TEST_PROGRAMS)
 

builtin-clone.c

@@ -19,6 +19,7 @@
 #include "strbuf.h"
 #include "dir.h"
 #include "pack-refs.h"
+#include "sigchain.h"
 
 /*
  * Overall FIXMEs:
@@ -288,7 +289,7 @@ static void remove_junk(void)
 static void remove_junk_on_signal(int signo)
 {
 	remove_junk();
-	signal(SIGINT, SIG_DFL);
+	sigchain_pop(signo);
 	raise(signo);
 }
 
@@ -441,7 +442,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	}
 	junk_git_dir = git_dir;
 	atexit(remove_junk);
-	signal(SIGINT, remove_junk_on_signal);
+	sigchain_push_common(remove_junk_on_signal);
 
 	setenv(CONFIG_ENVIRONMENT, xstrdup(mkpath("%s/config", git_dir)), 1);
 

builtin-fetch--tool.c

@@ -2,6 +2,7 @@
 #include "cache.h"
 #include "refs.h"
 #include "commit.h"
+#include "sigchain.h"
 
 static char *get_stdin(void)
 {
@@ -186,7 +187,7 @@ static void remove_keep(void)
 static void remove_keep_on_signal(int signo)
 {
 	remove_keep();
-	signal(SIGINT, SIG_DFL);
+	sigchain_pop(signo);
 	raise(signo);
 }
 
@@ -245,7 +246,7 @@ static int fetch_native_store(FILE *fp,
 	char buffer[1024];
 	int err = 0;
 
-	signal(SIGINT, remove_keep_on_signal);
+	sigchain_push_common(remove_keep_on_signal);
 	atexit(remove_keep);
 
 	while (fgets(buffer, sizeof(buffer), stdin)) {

builtin-fetch.c

@@ -10,6 +10,7 @@
 #include "transport.h"
 #include "run-command.h"
 #include "parse-options.h"
+#include "sigchain.h"
 
 static const char * const builtin_fetch_usage[] = {
 	"git fetch [options] [<repository> <refspec>...]",
@@ -58,7 +59,7 @@ static void unlock_pack(void)
 static void unlock_pack_on_signal(int signo)
 {
 	unlock_pack();
-	signal(SIGINT, SIG_DFL);
+	sigchain_pop(signo);
 	raise(signo);
 }
 
@@ -672,7 +673,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 		ref_nr = j;
 	}
 
-	signal(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);

compat/mingw.h

@@ -21,12 +21,12 @@ typedef int pid_t;
 #define WEXITSTATUS(x) ((x) & 0xff)
 #define WIFSIGNALED(x) ((unsigned)(x) > 259)
 
-#define SIGKILL 0
-#define SIGCHLD 0
-#define SIGPIPE 0
-#define SIGHUP 0
-#define SIGQUIT 0
-#define SIGALRM 100
+#define SIGHUP 1
+#define SIGQUIT 3
+#define SIGKILL 9
+#define SIGPIPE 13
+#define SIGALRM 14
+#define SIGCHLD 17
 
 #define F_GETFD 1
 #define F_SETFD 2

diff.c

@@ -12,6 +12,7 @@
 #include "run-command.h"
 #include "utf8.h"
 #include "userdiff.h"
+#include "sigchain.h"
 
 #ifdef NO_FAST_WORKING_DIRECTORY
 #define FAST_WORKING_DIRECTORY 0
@@ -170,6 +171,33 @@ static struct diff_tempfile {
 	char tmp_path[PATH_MAX];
 } diff_temp[2];
 
+static struct diff_tempfile *claim_diff_tempfile(void) {
+	int i;
+	for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
+		if (!diff_temp[i].name)
+			return diff_temp + i;
+	die("BUG: diff is failing to clean up its tempfiles");
+}
+
+static int remove_tempfile_installed;
+
+static void remove_tempfile(void)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
+		if (diff_temp[i].name == diff_temp[i].tmp_path) {
+			unlink(diff_temp[i].name);
+			diff_temp[i].name = NULL;
+		}
+}
+
+static void remove_tempfile_on_signal(int signo)
+{
+	remove_tempfile();
+	sigchain_pop(signo);
+	raise(signo);
+}
+
 static int count_lines(const char *data, int size)
 {
 	int count, ch, completely_empty = 1, nl_just_seen = 0;
@@ -1940,10 +1968,11 @@ static void prep_temp_blob(struct diff_tempfile *temp,
 	sprintf(temp->mode, "%06o", mode);
 }
 
-static void prepare_temp_file(const char *name,
-			      struct diff_tempfile *temp,
-			      struct diff_filespec *one)
+static struct diff_tempfile *prepare_temp_file(const char *name,
+		struct diff_filespec *one)
 {
+	struct diff_tempfile *temp = claim_diff_tempfile();
+
 	if (!DIFF_FILE_VALID(one)) {
 	not_a_valid_file:
 		/* A '-' entry produces this for file-2, and
@@ -1952,7 +1981,13 @@ static void prepare_temp_file(const char *name,
 		temp->name = "/dev/null";
 		strcpy(temp->hex, ".");
 		strcpy(temp->mode, ".");
-		return;
+		return temp;
+	}
+
+	if (!remove_tempfile_installed) {
+		atexit(remove_tempfile);
+		sigchain_push_common(remove_tempfile_on_signal);
+		remove_tempfile_installed = 1;
 	}
 
 	if (!one->sha1_valid ||
@@ -1992,7 +2027,7 @@ static void prepare_temp_file(const char *name,
 			 */
 			sprintf(temp->mode, "%06o", one->mode);
 		}
-		return;
+		return temp;
 	}
 	else {
 		if (diff_populate_filespec(one, 0))
@@ -2000,24 +2035,7 @@ static void prepare_temp_file(const char *name,
 		prep_temp_blob(temp, one->data, one->size,
 			       one->sha1, one->mode);
 	}
-}
-
-static void remove_tempfile(void)
-{
-	int i;
-
-	for (i = 0; i < 2; i++)
-		if (diff_temp[i].name == diff_temp[i].tmp_path) {
-			unlink(diff_temp[i].name);
-			diff_temp[i].name = NULL;
-		}
-}
-
-static void remove_tempfile_on_signal(int signo)
-{
-	remove_tempfile();
-	signal(SIGINT, SIG_DFL);
-	raise(signo);
+	return temp;
 }
 
 /* An external diff command takes:
@@ -2035,34 +2053,22 @@ static void run_external_diff(const char *pgm,
 			      int complete_rewrite)
 {
 	const char *spawn_arg[10];
-	struct diff_tempfile *temp = diff_temp;
 	int retval;
-	static int atexit_asked = 0;
-	const char *othername;
 	const char **arg = &spawn_arg[0];
 
-	othername = (other? other : name);
-	if (one && two) {
-		prepare_temp_file(name, &temp[0], one);
-		prepare_temp_file(othername, &temp[1], two);
-		if (! atexit_asked &&
-		    (temp[0].name == temp[0].tmp_path ||
-		     temp[1].name == temp[1].tmp_path)) {
-			atexit_asked = 1;
-			atexit(remove_tempfile);
-		}
-		signal(SIGINT, remove_tempfile_on_signal);
-	}
-
 	if (one && two) {
+		struct diff_tempfile *temp_one, *temp_two;
+		const char *othername = (other ? other : name);
+		temp_one = prepare_temp_file(name, one);
+		temp_two = prepare_temp_file(othername, two);
 		*arg++ = pgm;
 		*arg++ = name;
-		*arg++ = temp[0].name;
-		*arg++ = temp[0].hex;
-		*arg++ = temp[0].mode;
-		*arg++ = temp[1].name;
-		*arg++ = temp[1].hex;
-		*arg++ = temp[1].mode;
+		*arg++ = temp_one->name;
+		*arg++ = temp_one->hex;
+		*arg++ = temp_one->mode;
+		*arg++ = temp_two->name;
+		*arg++ = temp_two->hex;
+		*arg++ = temp_two->mode;
 		if (other) {
 			*arg++ = other;
 			*arg++ = xfrm_msg;
@@ -3537,15 +3543,15 @@ void diff_unmerge(struct diff_options *options,
 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
 		size_t *outsize)
 {
-	struct diff_tempfile temp;
+	struct diff_tempfile *temp;
 	const char *argv[3];
 	const char **arg = argv;
 	struct child_process child;
 	struct strbuf buf = STRBUF_INIT;
 
-	prepare_temp_file(spec->path, &temp, spec);
+	temp = prepare_temp_file(spec->path, spec);
 	*arg++ = pgm;
-	*arg++ = temp.name;
+	*arg++ = temp->name;
 	*arg = NULL;
 
 	memset(&child, 0, sizeof(child));
@@ -3554,13 +3560,11 @@ static char *run_textconv(const char *pgm, struct diff_filespec *spec,
 	if (start_command(&child) != 0 ||
 	    strbuf_read(&buf, child.out, 0) < 0 ||
 	    finish_command(&child) != 0) {
-		if (temp.name == temp.tmp_path)
-			unlink(temp.name);
+		remove_tempfile();
 		error("error running textconv command '%s'", pgm);
 		return NULL;
 	}
-	if (temp.name == temp.tmp_path)
-		unlink(temp.name);
+	remove_tempfile();
 
 	return strbuf_detach(&buf, outsize);
 }

http-push.c

@@ -10,6 +10,7 @@
 #include "exec_cmd.h"
 #include "remote.h"
 #include "list-objects.h"
+#include "sigchain.h"
 
 #include <expat.h>
 
@@ -1384,7 +1385,7 @@ static void remove_locks(void)
 static void remove_locks_on_signal(int signo)
 {
 	remove_locks();
-	signal(signo, SIG_DFL);
+	sigchain_pop(signo);
 	raise(signo);
 }
 
@@ -2277,10 +2278,7 @@ int main(int argc, char **argv)
 		goto cleanup;
 	}
 
-	signal(SIGINT, remove_locks_on_signal);
-	signal(SIGHUP, remove_locks_on_signal);
-	signal(SIGQUIT, remove_locks_on_signal);
-	signal(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;

lockfile.c

@@ -2,6 +2,7 @@
  * Copyright (c) 2005, Junio C Hamano
  */
 #include "cache.h"
+#include "sigchain.h"
 
 static struct lock_file *lock_file_list;
 static const char *alternate_index_output;
@@ -24,7 +25,7 @@ static void remove_lock_file(void)
 static void remove_lock_file_on_signal(int signo)
 {
 	remove_lock_file();
-	signal(signo, SIG_DFL);
+	sigchain_pop(signo);
 	raise(signo);
 }
 
@@ -136,11 +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) {
-			signal(SIGINT, remove_lock_file_on_signal);
-			signal(SIGHUP, remove_lock_file_on_signal);
-			signal(SIGTERM, remove_lock_file_on_signal);
-			signal(SIGQUIT, remove_lock_file_on_signal);
-			signal(SIGPIPE, remove_lock_file_on_signal);
+			sigchain_push_common(remove_lock_file_on_signal);
 			atexit(remove_lock_file);
 		}
 		lk->owner = getpid();

pager.c

@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "run-command.h"
+#include "sigchain.h"
 
 /*
  * This is split up from the rest of git so that we can do
@@ -38,6 +39,13 @@ static void wait_for_pager(void)
 	finish_command(&pager_process);
 }
 
+static void wait_for_pager_signal(int signo)
+{
+	wait_for_pager();
+	sigchain_pop(signo);
+	raise(signo);
+}
+
 void setup_pager(void)
 {
 	const char *pager = getenv("GIT_PAGER");
@@ -75,6 +83,7 @@ void setup_pager(void)
 	close(pager_process.in);
 
 	/* this makes sure that the parent terminates after the pager */
+	sigchain_push_common(wait_for_pager_signal);
 	atexit(wait_for_pager);
 }
 

sigchain.c

@@ -0,0 +1,52 @@
+#include "sigchain.h"
+#include "cache.h"
+
+#define SIGCHAIN_MAX_SIGNALS 32
+
+struct sigchain_signal {
+	sigchain_fun *old;
+	int n;
+	int alloc;
+};
+static struct sigchain_signal signals[SIGCHAIN_MAX_SIGNALS];
+
+static void check_signum(int sig)
+{
+	if (sig < 1 || sig >= SIGCHAIN_MAX_SIGNALS)
+		die("BUG: signal out of range: %d", sig);
+}
+
+int sigchain_push(int sig, sigchain_fun f)
+{
+	struct sigchain_signal *s = signals + sig;
+	check_signum(sig);
+
+	ALLOC_GROW(s->old, s->n + 1, s->alloc);
+	s->old[s->n] = signal(sig, f);
+	if (s->old[s->n] == SIG_ERR)
+		return -1;
+	s->n++;
+	return 0;
+}
+
+int sigchain_pop(int sig)
+{
+	struct sigchain_signal *s = signals + sig;
+	check_signum(sig);
+	if (s->n < 1)
+		return 0;
+
+	if (signal(sig, s->old[s->n - 1]) == SIG_ERR)
+		return -1;
+	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);
+}

sigchain.h

@@ -0,0 +1,11 @@
+#ifndef SIGCHAIN_H
+#define SIGCHAIN_H
+
+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 */

t/t0005-signals.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+
+test_description='signals work as we expect'
+. ./test-lib.sh
+
+cat >expect <<EOF
+three
+two
+one
+EOF
+
+test_expect_success 'sigchain works' '
+	test-sigchain >actual
+	case "$?" in
+	143) true ;; # POSIX w/ SIGTERM=15
+	  3) true ;; # Windows
+	  *) false ;;
+	esac &&
+	test_cmp expect actual
+'
+
+test_done

test-sigchain.c

@@ -0,0 +1,22 @@
+#include "sigchain.h"
+#include "cache.h"
+
+#define X(f) \
+static void f(int sig) { \
+	puts(#f); \
+	fflush(stdout); \
+	sigchain_pop(sig); \
+	raise(sig); \
+}
+X(one)
+X(two)
+X(three)
+#undef X
+
+int main(int argc, char **argv) {
+	sigchain_push(SIGTERM, one);
+	sigchain_push(SIGTERM, two);
+	sigchain_push(SIGTERM, three);
+	raise(SIGTERM);
+	return 0;
+}