]> git.ipfire.org Git - thirdparty/util-linux.git/blobdiff - misc-utils/mcookie.c
include/pidfd-utils: remove hardcoded syscall fallback
[thirdparty/util-linux.git] / misc-utils / mcookie.c
index 9bfa9759cb6bf1a99580c9d15d9468ed5cd2efda..99df4f4a6d973d8dad5b102553fe3da3088b8693 100644 (file)
@@ -1,9 +1,13 @@
-/* mcookie.c -- Generates random numbers for xauth
+/*
+ * No copyright is claimed.  This code is in the public domain; do with
+ * it what you wish.
+ *
+ * mcookie.c -- Generates random numbers for xauth
  * Created: Fri Feb  3 10:42:48 1995 by faith@cs.unc.edu
  * Revised: Fri Mar 19 07:48:01 1999 by faith@acm.org
  * Public Domain 1995, 1999 Rickard E. Faith (faith@acm.org)
  * This program comes with ABSOLUTELY NO WARRANTY.
- * 
+ *
  * This program gathers some random bits of data and used the MD5
  * message-digest algorithm to generate a 128-bit hexadecimal number for
  * use with xauth(1).
@@ -23,7 +27,9 @@
 #include "nls.h"
 #include "closestream.h"
 #include "randutils.h"
+#include "strutils.h"
 #include "xalloc.h"
+#include "all-io.h"
 
 #include <fcntl.h>
 #include <getopt.h>
@@ -38,81 +44,108 @@ enum {
        RAND_BYTES = 128
 };
 
+struct mcookie_control {
+       struct  UL_MD5Context ctx;
+       char    **files;
+       size_t  nfiles;
+       uint64_t maxsz;
+
+       unsigned int verbose:1;
+};
+
 /* The basic function to hash a file */
-static off_t hash_file(struct MD5Context *ctx, int fd)
+static uint64_t hash_file(struct mcookie_control *ctl, int fd)
 {
-       off_t count = 0;
-       ssize_t r;
        unsigned char buf[BUFFERSIZE];
+       uint64_t wanted, count;
+
+       wanted = ctl->maxsz ? ctl->maxsz : sizeof(buf);
 
-       while ((r = read(fd, buf, sizeof(buf))) > 0) {
-               MD5Update(ctx, buf, r);
+       for (count = 0; count < wanted; ) {
+               size_t rdsz = sizeof(buf);
+               ssize_t r;
+
+               if (wanted - count < rdsz)
+                       rdsz = wanted - count;
+
+               r = read_all(fd, (char *) buf, rdsz);
+               if (r <= 0)
+                       break;
+               ul_MD5Update(&ctl->ctx, buf, r);
                count += r;
        }
        /* Separate files with a null byte */
        buf[0] = '\0';
-       MD5Update(ctx, buf, 1);
+       ul_MD5Update(&ctl->ctx, buf, 1);
        return count;
 }
 
-static void __attribute__ ((__noreturn__)) usage(FILE * out)
+static void __attribute__((__noreturn__)) usage(void)
 {
-       fputs(_("\nUsage:\n"), out);
-       fprintf(out,
-             _(" %s [options]\n"), program_invocation_short_name);
+       FILE *out = stdout;
+       fputs(USAGE_HEADER, out);
+       fprintf(out, _(" %s [options]\n"), program_invocation_short_name);
+
+       fputs(USAGE_SEPARATOR, out);
+       fputs(_("Generate magic cookies for xauth.\n"), out);
+
+       fputs(USAGE_OPTIONS, out);
+       fputs(_(" -f, --file <file>     use file as a cookie seed\n"), out);
+       fputs(_(" -m, --max-size <num>  limit how much is read from seed files\n"), out);
+       fputs(_(" -v, --verbose         explain what is being done\n"), out);
+
+       fputs(USAGE_SEPARATOR, out);
+       fprintf(out, USAGE_HELP_OPTIONS(23));
 
-       fputs(_("\nOptions:\n"), out);
-       fputs(_(" -f, --file <file> use file as a cookie seed\n"
-               " -v, --verbose     explain what is being done\n"
-               " -V, --version     output version information and exit\n"
-               " -h, --help        display this help and exit\n\n"), out);
+       fputs(USAGE_ARGUMENTS, out);
+       fprintf(out, USAGE_ARG_SIZE(_("<num>")));
 
-       exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+       fprintf(out, USAGE_MAN_TAIL("mcookie(1)"));
+
+       exit(EXIT_SUCCESS);
 }
 
-static void randomness_from_files(char **files, int nfiles,
-                                 struct MD5Context *ctx, int verbose)
+static void randomness_from_files(struct mcookie_control *ctl)
 {
-       int fd, i;
-       int count = 0;
+       size_t i;
+
+       for (i = 0; i < ctl->nfiles; i++) {
+               const char *fname = ctl->files[i];
+               size_t count;
+               int fd;
 
-       for (i = 0; i < nfiles; i++) {
-               if (files[i][0] == '-' && !files[i][1])
+               if (*fname == '-' && !*(fname + 1))
                        fd = STDIN_FILENO;
                else
-                       fd = open(files[i], O_RDONLY);
+                       fd = open(fname, O_RDONLY);
 
                if (fd < 0) {
-                       warn(_("cannot open %s"), files[i]);
+                       warn(_("cannot open %s"), fname);
                } else {
-                       count = hash_file(ctx, fd);
-                       if (verbose)
+                       count = hash_file(ctl, fd);
+                       if (ctl->verbose)
                                fprintf(stderr,
-                                       P_("Got %d byte from %s\n",
-                                          "Got %d bytes from %s\n", count),
-                                       count, files[i]);
-
-                       if (fd != STDIN_FILENO)
-                               if (close(fd))
-                                       err(EXIT_FAILURE,
-                                           _("closing %s failed"), files[i]);
+                                       P_("Got %zu byte from %s\n",
+                                          "Got %zu bytes from %s\n", count),
+                                       count, fname);
+
+                       if (fd != STDIN_FILENO && close(fd))
+                               err(EXIT_FAILURE, _("closing %s failed"), fname);
                }
        }
 }
 
 int main(int argc, char **argv)
 {
+       struct mcookie_control ctl = { .verbose = 0 };
        size_t i;
-       struct MD5Context ctx;
-       unsigned char digest[MD5LENGTH];
+       unsigned char digest[UL_MD5LENGTH];
        unsigned char buf[RAND_BYTES];
-       char **files = NULL;
-       int nfiles;
        int c;
-       int verbose = 0;
 
        static const struct option longopts[] = {
                {"file", required_argument, NULL, 'f'},
+               {"max-size", required_argument, NULL, 'm'},
                {"verbose", no_argument, NULL, 'v'},
                {"version", no_argument, NULL, 'V'},
                {"help", no_argument, NULL, 'h'},
@@ -122,45 +155,48 @@ int main(int argc, char **argv)
        setlocale(LC_ALL, "");
        bindtextdomain(PACKAGE, LOCALEDIR);
        textdomain(PACKAGE);
-       atexit(close_stdout);
-
-       MD5Init(&ctx);
+       close_stdout_atexit();
 
-       if (2 < argc) {
-               files = xmalloc(sizeof(char *) * argc);
-               nfiles = 0;
-       }
-
-       while ((c =
-               getopt_long(argc, argv, "f:vVh", longopts, NULL)) != -1)
+       while ((c = getopt_long(argc, argv, "f:m:vVh", longopts, NULL)) != -1) {
                switch (c) {
                case 'v':
-                       verbose = 1;
+                       ctl.verbose = 1;
                        break;
                case 'f':
-                       files[nfiles] = optarg;
-                       nfiles++;
+                       if (!ctl.files)
+                               ctl.files = xmalloc(sizeof(char *) * argc);
+                       ctl.files[ctl.nfiles++] = optarg;
+                       break;
+               case 'm':
+                       ctl.maxsz = strtosize_or_err(optarg,
+                                                    _("failed to parse length"));
                        break;
+
                case 'V':
-                       printf(UTIL_LINUX_VERSION);
-                       return EXIT_SUCCESS;
+                       print_version(EXIT_SUCCESS);
                case 'h':
-                       usage(stdout);
+                       usage();
                default:
-                       usage(stderr);
+                       errtryhelp(EXIT_FAILURE);
                }
+       }
+
+       if (ctl.maxsz && ctl.nfiles == 0)
+               warnx(_("--max-size ignored when used without --file"));
 
-       randomness_from_files(files, nfiles, &ctx, verbose);
-       free(files);
+       ul_MD5Init(&ctl.ctx);
+       randomness_from_files(&ctl);
+       free(ctl.files);
 
-       random_get_bytes(&buf, RAND_BYTES);
-       MD5Update(&ctx, buf, RAND_BYTES);
-       if (verbose)
-               fprintf(stderr,
-                       _("Got %d bytes from %s\n"), RAND_BYTES, random_tell_source());
+       ul_random_get_bytes(&buf, RAND_BYTES);
+       ul_MD5Update(&ctl.ctx, buf, RAND_BYTES);
+       if (ctl.verbose)
+               fprintf(stderr, P_("Got %d byte from %s\n",
+                                  "Got %d bytes from %s\n", RAND_BYTES),
+                               RAND_BYTES, random_tell_source());
 
-       MD5Final(digest, &ctx);
-       for (i = 0; i < MD5LENGTH; i++)
+       ul_MD5Final(digest, &ctl.ctx);
+       for (i = 0; i < UL_MD5LENGTH; i++)
                printf("%02x", digest[i]);
        putchar('\n');