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Revision 41f222e87a9062833712367d66114cae90b3769a authored by Linus Torvalds on 28 October 2005, 16:45:53 UTC, committed by Junio C Hamano on 28 October 2005, 21:25:02 UTC 
Be marginally more careful about removing objects
 
The git philosophy when it comes to disk accesses is "Laugh in the face of
danger".

Notably, since we never modify an existing object, we don't really care
that deeply about flushing things to disk, since even if the machine
crashes in the middle of a git operation, you can never really have lost
any old work. At most, you'd need to figure out the proper heads (which
git-fsck-objects can do for you) and re-do the operation.

However, there's two exceptions to this: pruning and repacking. Those
operations will actually _delete_ old objects that they know about in
other ways (ie that they just repacked, or that they have found in other
places).

However, since they actually modify old state, we should thus be a bit
more careful about them. If the machine crashes and the duplicate new
objects haven't been flushed to disk, you can actually be in trouble.

This is trivially stupid about it by calling "sync" before removing the
objects. Not very smart, but we're talking about special operations than
are usually done once a week if that.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
1 parent 50b8e35
Raw File
rsh.c 
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>

#include "rsh.h"
#include "quote.h"
#include "cache.h"

#define COMMAND_SIZE 4096

/*
 * Append a string to a string buffer, with or without shell quoting.
 * Return true if the buffer overflowed.
 */
static int add_to_string(char **ptrp, int *sizep, const char *str, int quote)
{
	char *p = *ptrp;
	int size = *sizep;
	int oc;
	int err = 0;

	if ( quote ) {
		oc = sq_quote_buf(p, size, str);
	} else {
		oc = strlen(str);
		memcpy(p, str, (oc >= size) ? size-1 : oc);
	}

	if ( oc >= size ) {
		err = 1;
		oc = size-1;
	}

	*ptrp  += oc;
	**ptrp  = '\0';
	*sizep -= oc;
	return err;
}

int setup_connection(int *fd_in, int *fd_out, const char *remote_prog, 
		     char *url, int rmt_argc, char **rmt_argv)
{
	char *host;
	char *path;
	int sv[2];
	char command[COMMAND_SIZE];
	char *posn;
	int sizen;
	int of;
	int i;

	if (!strcmp(url, "-")) {
		*fd_in = 0;
		*fd_out = 1;
		return 0;
	}

	host = strstr(url, "//");
	if (host) {
		host += 2;
		path = strchr(host, '/');
	} else {
		host = url;
		path = strchr(host, ':');
		if (path)
			*(path++) = '\0';
	}
	if (!path) {
		return error("Bad URL: %s", url);
	}
	/* $GIT_RSH <host> "env GIT_DIR=<path> <remote_prog> <args...>" */
	sizen = COMMAND_SIZE;
	posn = command;
	of = 0;
	of |= add_to_string(&posn, &sizen, "env ", 0);
	of |= add_to_string(&posn, &sizen, GIT_DIR_ENVIRONMENT "=", 0);
	of |= add_to_string(&posn, &sizen, path, 1);
	of |= add_to_string(&posn, &sizen, " ", 0);
	of |= add_to_string(&posn, &sizen, remote_prog, 1);

	for ( i = 0 ; i < rmt_argc ; i++ ) {
		of |= add_to_string(&posn, &sizen, " ", 0);
		of |= add_to_string(&posn, &sizen, rmt_argv[i], 1);
	}

	of |= add_to_string(&posn, &sizen, " -", 0);

	if ( of )
		return error("Command line too long");

	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv))
		return error("Couldn't create socket");

	if (!fork()) {
		const char *ssh, *ssh_basename;
		ssh = getenv("GIT_SSH");
		if (!ssh) ssh = "ssh";
		ssh_basename = strrchr(ssh, '/');
		if (!ssh_basename)
			ssh_basename = ssh;
		else
			ssh_basename++;
		close(sv[1]);
		dup2(sv[0], 0);
		dup2(sv[0], 1);
		execlp(ssh, ssh_basename, host, command, NULL);
	}
	close(sv[0]);
	*fd_in = sv[1];
	*fd_out = sv[1];
	return 0;
}
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