[Buildroot] [PATCH 1/3] e2fsprogs: nommu: Add patch to use vfork in nommu arch.

[Arnout Vandecappelle <arnout@mind.be>]

  Hi Sonic,

  Again, it doesn't look like these fork replacements will work...

On 15/11/13 09:31, sonic.adi at gmail.com wrote:
> From: Sonic Zhang <sonic.zhang@analog.com>
>
> Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
> ---
>   package/e2fsprogs/e2fsprogs-nommu.patch | 231 ++++++++++++++++++++++++++++++++
>   1 file changed, 231 insertions(+)
>   create mode 100644 package/e2fsprogs/e2fsprogs-nommu.patch
>
> diff --git a/package/e2fsprogs/e2fsprogs-nommu.patch b/package/e2fsprogs/e2fsprogs-nommu.patch
> new file mode 100644
> index 0000000..6aef365
> --- /dev/null
> +++ b/package/e2fsprogs/e2fsprogs-nommu.patch
> @@ -0,0 +1,231 @@
> +--- e2fsprogs-1.42.4/e2fsck/logfile.c	2012-05-29 09:29:48.000000000 +0800
> ++++ e2fsprogs-1.42.4.nommu/e2fsck/logfile.c	2012-09-24 17:49:18.878104451 +0800
> +@@ -220,7 +220,11 @@
> + 		exit(1);
> + 	}
> +
> ++#ifndef HAVE_FORK
> ++	pid = vfork();
> ++#else
> + 	pid = fork();
> ++#endif

  This one creates a child process that will read from an fd that is 
written by its parent, so I don't think this will work (parent is 
suspended until child exec's or exits). However, because of the call to 
daemon() in-between, it might work. Have you tested it?

> + 	if (pid < 0) {
> + 		perror("fork");
> + 		exit(1);
> +@@ -264,7 +268,11 @@
> + 			outbufsize -= c;
> + 			cp += c;
> + 		}
> ++#ifndef HAVE_FORK
> ++		_exit(0);
> ++#else
> + 		exit(0);
> ++#endif
> + 	}
> +
> + 	close(fds[0]);
> +--- e2fsprogs-1.42.4/lib/ss/pager.c	2012-03-19 02:18:33.000000000 +0800
> ++++ e2fsprogs-1.42.4.nommu/lib/ss/pager.c	2012-09-24 17:54:33.862356418 +0800
> +@@ -79,7 +79,11 @@
> + 	if (pipe(filedes) != 0)
> + 		return(-1);
> +
> ++#ifndef HAVE_FORK
> ++	switch(vfork()) {
> ++#else
> + 	switch(fork()) {
> ++#endif
> + 	case -1:
> + 		return(-1);
> + 	case 0:
> +--- e2fsprogs-1.42.4/lib/ss/help.c	2012-03-19 02:18:33.000000000 +0800
> ++++ e2fsprogs-1.42.4.nommu/lib/ss/help.c	2012-09-24 17:55:00.326105930 +0800
> +@@ -107,7 +107,11 @@
> + 	free(buf);
> + 	return;
> +     }
> ++#ifndef HAVE_FORK
> ++    switch (child = vfork()) {
> ++#else
> +     switch (child = fork()) {
> ++#endif
> +     case -1:
> + 	ss_perror(sci_idx, errno, "Can't fork for pager");
> + 	return;
> +--- e2fsprogs-1.42.4/lib/fpopen.c	2012-03-19 02:18:33.000000000 +0800
> ++++ e2fsprogs-1.42.4.nommu/lib/fpopen.c	2012-09-24 17:55:54.050106645 +0800
> +@@ -94,7 +94,11 @@
> + 		return NULL;
> +
> + 	/* Fork and execute the correct program. */
> ++#ifndef HAVE_FORK
> ++	if ((pid = vfork()) < 0) {
> ++#else
> + 	if ((pid = fork()) < 0) {
> ++#endif
> + 		perror("fork");
> + 		return NULL;
> + 	} else if (pid == 0) {
> +@@ -109,7 +113,11 @@
> + 		}
> + 		(void) execvp(prog, argv);
> + 		perror(prog);
> ++#ifndef HAVE_FORK
> ++		_exit(1);
> ++#else
> + 		exit(1);
> ++#endif
> + 	}
> + 	return fdopen(do_stdin ? fds[1] : fds[0], mode);
> + }
> +--- e2fsprogs-1.42.4/lib/uuid/gen_uuid.c	2012-03-19 02:18:33.000000000 +0800
> ++++ e2fsprogs-1.42.4.nommu/lib/uuid/gen_uuid.c	2012-09-24 17:56:41.186106057 +0800
> +@@ -504,11 +504,19 @@
> + 		if (access_ret == 0 && (st.st_mode & (S_ISUID | S_ISGID)) == 0)
> + 			access_ret = access(UUIDD_DIR, W_OK);
> + 		if (access_ret == 0 && start_attempts++ < 5) {
> ++#ifndef HAVE_FORK
> ++			if ((pid = vfork()) == 0) {
> ++#else
> + 			if ((pid = fork()) == 0) {
> ++#endif
> + 				close_all_fds();
> + 				execl(uuidd_path, "uuidd", "-qT", "300",
> + 				      (char *) NULL);
> ++#ifndef HAVE_FORK
> ++				_exit(1);
> ++#else
> + 				exit(1);
> ++#endif
> + 			}
> + 			(void) waitpid(pid, 0, 0);
> + 			if (connect(s, (const struct sockaddr *) &srv_addr,
> +--- e2fsprogs-1.42.4/misc/uuidd.c	2012-03-19 02:18:33.000000000 +0800
> ++++ e2fsprogs-1.42.4.nommu/misc/uuidd.c	2012-09-24 17:57:49.630106531 +0800
> +@@ -56,7 +56,11 @@
> + static void die(const char *msg)
> + {
> + 	perror(msg);
> ++#ifndef HAVE_FORK
> ++	_exit(1);
> ++#else
> + 	exit(1);
> ++#endif
> + }
> +
> + static void create_daemon(void)
> +@@ -64,7 +68,11 @@
> + 	pid_t pid;
> + 	uid_t euid;
> +
> ++#ifndef HAVE_FORK
> ++	pid = vfork();
> ++#else
> + 	pid = fork();
> ++#endif

  This looks like a home-grown implementation of daemon() - why didn't 
T.T'so just you daemon()? Anyway, it probably won't work because the 
child returns from the function, thereby corrupting the parent's stack 
frame. It may work accidentally, though.

> + 	if (pid == -1) {
> + 		perror("fork");
> + 		exit(1);
> +--- e2fsprogs-1.42.4/misc/fsck.c	2012-04-27 06:44:12.000000000 +0800
> ++++ e2fsprogs-1.42.4.nommu/misc/fsck.c	2012-09-24 17:52:49.297070304 +0800
> +@@ -491,7 +491,11 @@
> + 	/* Fork and execute the correct program. */
> + 	if (noexecute)
> + 		pid = -1;
> ++#ifndef HAVE_FORK
> ++	else if ((pid = vfork()) < 0) {
> ++#else
> + 	else if ((pid = fork()) < 0) {
> ++#endif
> + 		perror("fork");
> + 		free(inst);
> + 		return errno;
> +@@ -501,7 +505,11 @@
> + 		(void) execv(s, argv);
> + 		perror(argv[0]);
> + 		free(inst);
> ++#ifndef HAVE_FORK
> ++		_exit(EXIT_ERROR);
> ++#else
> + 		exit(EXIT_ERROR);
> ++#endif
> + 	}
> +
> + 	for (i=0; i < argc; i++)
> +@@ -641,10 +649,18 @@
> + 			 * time to set up the signal handler
> + 			 */
> + 			if (inst2->start_time < time(0)+2) {
> ++#ifndef HAVE_FORK
> ++				if (vfork() == 0) {
> ++#else
> + 				if (fork() == 0) {
> ++#endif
> + 					sleep(1);
> + 					kill(inst2->pid, SIGUSR1);
> ++#ifndef HAVE_FORK
> ++					_exit(0);
> ++#else
> + 					exit(0);
> ++#endif

  Hm, this looks like cut and paste code from util-linux, where I 
commented on a better way to implement this.

> + 				}
> + 			} else
> + 				kill(inst2->pid, SIGUSR1);
> +--- e2fsprogs-1.42.4/misc/logsave.c	2012-03-19 02:18:33.000000000 +0800
> ++++ e2fsprogs-1.42.4.nommu/misc/logsave.c	2012-09-24 17:51:18.062105881 +0800
> +@@ -181,7 +181,11 @@
> + #endif
> + #endif
> +
> ++#ifndef HAVE_FORK
> ++	pid = vfork();
> ++#else
> + 	pid = fork();
> ++#endif
> + 	if (pid < 0) {
> + 		perror("vfork");
> + 		exit(1);
> +@@ -193,7 +197,11 @@
> +
> + 		execvp(argv[0], argv);
> + 		perror(argv[0]);
> ++#ifndef HAVE_FORK
> ++		_exit(1);
> ++#else
> + 		exit(1);
> ++#endif
> + 	}
> + 	child_pid = pid;
> + 	close(fds[1]);
> +@@ -307,7 +315,11 @@
> + 	send_output("----------------\n", 0, send_flag);
> +
> + 	if (outbuf) {
> ++#ifndef HAVE_FORK
> ++		pid = vfork();
> ++#else
> + 		pid = fork();
> ++#endif

  The idea here is to background the process, but vfork doesn't actually 
background so you could just as well skip it completely. Or use daemon(1,1).


  Regards,
  Arnout

> + 		if (pid < 0) {
> + 			perror("fork");
> + 			exit(1);
> +@@ -329,5 +341,9 @@
> + 	if (outfd >= 0)
> + 		close(outfd);
> +
> ++#ifndef HAVE_FORK
> ++	_exit(rc);
> ++#else
> + 	exit(rc);
> ++#endif
> + }
> +--- e2fsprogs-1.42.8/configure.in.old	2013-11-11 15:31:35.626098053 +0800
> ++++ e2fsprogs-1.42.8/configure.in	2013-11-11 15:31:08.652956982 +0800
> +@@ -1020,6 +1020,7 @@
> + 	fallocate64
> + 	fchown
> + 	fdatasync
> ++	fork
> + 	fstat64
> + 	ftruncate64
> + 	getdtablesize
>


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7CB5 E4CC 6C2E EFD4 6E3D A754 F963 ECAB 2450 2F1F