Restore SIGCHLD to SIG_DFL where we care about waitpid().

It was reported that under one implementation of socks client
"git clone" fails with "error: waitpid failed (No child processes)",
because "git" is spawned after setting SIGCHLD to SIG_IGN.

Arguably it may be a broken setting, but we should protect
ourselves so that we can get reliable results from waitpid() for
the children we care about.

This patch resets SIGCHLD to SIG_DFL in three places:

 - connect.c::git_connect() - initiators of git native
   protocol transfer are covered with this.

 - daemon.c::main() - obviously.

 - merge-index.c::main() - obviously.

There are other programs that do fork() but do not waitpid():
http-push, imap-send.  upload-pack does not either, but in the
case of that program, each of the forked halves runs exec()
another program, so this change would not have much effect
there.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/connect.c b/connect.c
index 52d709e58d53f053ec00bfb9f31501684cbaf0e5..db7342e4d26baa50dd944ebf06fb8b66fea59aaa 100644 (file)
--- a/connect.c
+++ b/connect.c
@@ -581,6 +581,11 @@ int git_connect(int fd[2], char *url, const char *prog)
        enum protocol protocol = PROTO_LOCAL;
        int free_path = 0;
 
+       /* Without this we cannot rely on waitpid() to tell
+        * what happened to our children.
+        */
+       signal(SIGCHLD, SIG_DFL);
+
        host = strstr(url, "://");
        if(host) {
                *host = '\0';

diff --git a/daemon.c b/daemon.c
index 2f03f99d2d9f2ed9a23932e5104456f69b721116..10670047f267e86a6831562749914a8cf4187334 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -671,6 +671,11 @@ int main(int argc, char **argv)
        int inetd_mode = 0;
        int i;
 
+       /* Without this we cannot rely on waitpid() to tell
+        * what happened to our children.
+        */
+       signal(SIGCHLD, SIG_DFL);
+
        for (i = 1; i < argc; i++) {
                char *arg = argv[i];
 

diff --git a/merge-index.c b/merge-index.c
index 024196e7ac53cb9ad09b38ea646bad81aff33306..190e12fb7ceeb012a063f8c97b574e9650d95cc1 100644 (file)
--- a/merge-index.c
+++ b/merge-index.c
@@ -99,6 +99,11 @@ int main(int argc, char **argv)
 {
        int i, force_file = 0;
 
+       /* Without this we cannot rely on waitpid() to tell
+        * what happened to our children.
+        */
+       signal(SIGCHLD, SIG_DFL);
+
        if (argc < 3)
                usage("git-merge-index [-o] [-q] <merge-program> (-a | <filename>*)");