1.1 --- a/main.c	Mon Apr 07 00:06:22 2008 -0400
     1.2 +++ b/main.c	Mon Apr 07 00:35:27 2008 -0400
     1.3 @@ -5,6 +5,7 @@
     1.4  #include <string.h>
     1.5  #include <sys/stat.h>
     1.6  #include <unistd.h>
     1.7 +#include <fcntl.h>
     1.8  #include <dirent.h>
     1.9  #include <curl/curl.h>
    1.10  #include <fnmatch.h>
    1.11 @@ -530,33 +531,50 @@
    1.12  	struct razor_transaction *trans;
    1.13  	char path[PATH_MAX], new_path[PATH_MAX];
    1.14  	CURL *curl;
    1.15 -	int errors;
    1.16 +	int errors, fd;
    1.17 +
    1.18 +	/* Create the new next repo file up front to ensure exclusive
    1.19 +	 * access. */
    1.20 +	snprintf(new_path, sizeof new_path,
    1.21 +		 "%s%s/%s", root, razor_root_path, next_repo_filename);
    1.22 +	fd = open(new_path, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL, 0666);
    1.23 +	if (fd < 0) {
    1.24 +		fprintf(stderr, "failed to get lock file, "
    1.25 +			"maybe previous operation crashed?\n");
    1.26 +
    1.27 +		/* FIXME: Use fcntl advisory locking to figure out
    1.28 +		 * whether previous operation crashed or is still in
    1.29 +		 * progress. */
    1.30 +
    1.31 +		return -1;
    1.32 +	}
    1.33  
    1.34  	upstream = razor_set_open(rawhide_repo_filename);
    1.35  	snprintf(path, sizeof path,
    1.36  		 "%s%s/%s", root, razor_root_path, system_repo_filename);
    1.37  	system = razor_set_open(path);
    1.38 -	if (system == NULL || upstream == NULL)
    1.39 +	if (system == NULL || upstream == NULL) {
    1.40 +		unlink(new_path);
    1.41  		return 1;
    1.42 +	}
    1.43  	trans = razor_transaction_create(system, upstream,
    1.44  					 argc, argv, 0, NULL);
    1.45  	errors = razor_transaction_describe(trans);
    1.46 -	if (errors)
    1.47 +	if (errors) {
    1.48 +		unlink(new_path);
    1.49  		return 1;
    1.50 +	}
    1.51  
    1.52  	next = razor_transaction_finish(trans);
    1.53  
    1.54 -	/* FIXME: Need razor_set_write_to_fd() so we can open it excl
    1.55 -	 * up front here or fail if it already exists. */
    1.56 -	snprintf(new_path, sizeof new_path,
    1.57 -		 "%s%s/%s", root, razor_root_path, next_repo_filename);
    1.58 -
    1.59 -	razor_set_write(next, new_path);
    1.60 +	razor_set_write_to_fd(next, fd);
    1.61  	printf("wrote %s\n", new_path);
    1.62  
    1.63  	curl = curl_easy_init();
    1.64 -	if (curl == NULL)
    1.65 +	if (curl == NULL) {
    1.66 +		unlink(new_path);
    1.67  		return 1;
    1.68 +	}
    1.69  	razor_set_diff(system, next, download_package, curl);	
    1.70  	curl_easy_cleanup(curl);
    1.71