[Devel] Re: [PATCH 3/4] Add test case ptree1 - process tree using fileio

[Serge E. Hallyn]

Quoting sukadev at linux.vnet.ibm.com (sukadev at linux.vnet.ibm.com):
> From: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>
> 
> The test case continously copies a given input-file to an output-file,
> one record at a time. After copying, the test verifies that the two files
> have the same data (i.e ensures if test was checkpointed/restarted, the
> copy was still correct).  The test ends when the 'test_done()' condition
> is TRUE.
> 
> The accompanying wrapper runs the test in a loop and checkpoints/restarts
> the test.
> 
> Signed-off-by: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>
> ---
>  Makefile                   |    3 +-
>  process-tree/Makefile      |   13 +++
>  process-tree/ptree1.c      |  150 +++++++++++++++++++++++++++
>  process-tree/run-ptree1.sh |  244 ++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 409 insertions(+), 1 deletions(-)
>  create mode 100644 process-tree/Makefile
>  create mode 100644 process-tree/ptree1.c
>  create mode 100755 process-tree/run-ptree1.sh
> 
> diff --git a/Makefile b/Makefile
> index f59c89b..d709f7f 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1,4 +1,5 @@
> -SUBDIRS = counterloop fileio simple cr-ipc-test userns sleep libcrtest
> +SUBDIRS = counterloop fileio simple cr-ipc-test userns sleep libcrtest \
> +	  process-tree
> 
>  targets = ns_exec
> 
> diff --git a/process-tree/Makefile b/process-tree/Makefile
> new file mode 100644
> index 0000000..f76f60d
> --- /dev/null
> +++ b/process-tree/Makefile
> @@ -0,0 +1,13 @@
> +
> +targets		= ptree1
> +
> +INCLUDE		= ../libcrtest
> +LIBCRTEST	= ../libcrtest/common.o
> +
> +CFLAGS		= -I $(INCLUDE)
> +LDFLAGS		= $(LIBCRTEST) -lpthread 
> +
> +all: $(LIBCRTEST) $(targets)
> +
> +clean:
> +	rm -f *.o $(targets)
> diff --git a/process-tree/ptree1.c b/process-tree/ptree1.c
> new file mode 100644
> index 0000000..7df7c8e
> --- /dev/null
> +++ b/process-tree/ptree1.c
> @@ -0,0 +1,150 @@
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <wait.h>
> +#include <errno.h>
> +#include <string.h>
> +#include "common.h"
> +
> +/*
> + * Create a simple process tree and have each process in the tree
> + * (except the main) make a private copy of a given input * file,
> + * When the copy is done, compare the private copy with the input
> + * file and fail if they differ. If not, truncate the private copy
> + * and repeat the copying until test_done() is TRUE.
> + *
> + * Note: To avoid touching restart-blocks, don't sleep().
> + */
> +
> +int max_depth = 2;
> +int num_children = 2;
> +FILE *logfp;
> +char *src = "input.data";
> +#define LOG_FILE	"logs.d/log-ptree1"
> +
> +static void do_work(char *idstr)
> +{
> +	char dest[1024];
> +
> +	sprintf(dest, "log-%s.data", idstr);

not sure 'log-' is the right prefix... how about copy-%s.data
or something?

> +	copy_data(src, dest);
> +
> +	do_exit(0);
> +}
> +
> +static do_child(int depth, char *suffix);
> +
> +create_children(int depth, char *parent_suffix)
> +{
> +	int i;
> +	int child_pid;
> +	char suffix[1024];
> +
> +	for (i = 0; i < num_children; i++) {
> +		sprintf(suffix, "%s-%d", parent_suffix, i);

Since the depth is taken on command line, you need to either
malloc the char[]s, or do snprintf(suffix, 1024, ...) here
and elsewhere.

> +
> +		child_pid = fork();
> +		if (child_pid == 0)
> +			do_child(depth, suffix);
> +		else if (child_pid < 0) {
> +			fprintf(logfp, "fork() failed, depth %d, "
> +				"child %d, error %s\n", depth, i,
> +				strerror(errno));
> +			do_exit(1);
> +		}
> +	}
> +}
> +
> +do_child(int depth, char *suffix)
> +{
> +	int i;
> +	FILE *cfp;
> +	char cfile[256];
> +	char *mode = "w";
> +
> +	/*
> +	 * Recursively calls do_child() and both parent and child
> +	 * execute the code below
> +	 */
> +	fprintf(logfp, "do_child: depth %d, max_depth %d\n", depth, max_depth);
> +	fflush(logfp);
> +
> +	if (depth < max_depth)
> +		create_children(depth+1, suffix);
> +
> +	sprintf(cfile, "%s%s", LOG_FILE, suffix);
> +
> +	i = 0;
> +	while (!test_done()) {
> +		/* truncate the first time, append after that */
> +		cfp = fopen(cfile, mode);
> +		mode = "a";
> +		if (!cfp) {
> +			fprintf(logfp, "fopen(%s) failed, error %s\n", cfile,
> +					strerror(errno));
> +			do_exit(1);
> +		}
> +		fprintf(cfp, "pid %d: i %d\n", getpid(), i++);
> +		fflush(cfp);
> +
> +		do_work(suffix);
> +
> +		fflush(cfp);
> +		fclose(cfp);
> +	}
> +
> +	/* Wait for any children that pre-deceased us */
> +	do_wait(num_children);
> +
> +	do_exit(0);
> +}
> +
> +static void usage(char *argv[])
> +{
> +	printf("%s [h] [-d max-depth] [-n max-children]\n", argv[0]);
> +	printf("\t <max-depth> max depth of process tree, default 3\n");
> +	printf("\t <num-children> # of children per process, default 3\n");
> +	do_exit(1);
> +}
> +
> +main(int argc, char *argv[])
> +{
> +	int c;
> +	int i;
> +	int status;
> +
> +	logfp = fopen(LOG_FILE, "w");
> +	if (!logfp) {
> +		fprintf(stderr, "fopen(%s) failed, %s\n", LOG_FILE,
> +					strerror(errno));
> +		fflush(stderr);
> +		do_exit(1);
> +	}
> +
> +	if (test_done()) {
> +		printf("Remove %s before running test\n", TEST_DONE);
> +		do_exit(1);
> +	}
> +
> +	while ((c = getopt(argc, argv, "hd:n:")) != EOF) {
> +		switch (c) {
> +		case 'd': max_depth = atoi(optarg); break;
> +		case 'n': num_children = atoi(optarg); break;
> +		case 'h':
> +		default:
> +			usage(argv);
> +		}
> +	};
> +
> +	close(0);close(1);close(2);
> +
> +	create_children(1, "");
> +
> +	/*
> +	 * Now that we closed the special files and created process tree
> +	 * tell any wrapper scripts, we are ready for checkpoint
> +	 */
> +	checkpoint_ready();

How do you know a checkpoint is ready?

(Or is that not what this means?  :)

thanks,
-serge
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