gen_init_cpio: avoid stack overflow when expanding
[linux-3.10.git] / usr / gen_init_cpio.c
index 33dbcbf..aca6edc 100644 (file)
@@ -14,6 +14,7 @@
  * Original work by Jeff Garzik
  *
  * External file lists, symlink, pipe and fifo support by Thayne Harbaugh
+ * Hard link support by Luciano Rocha
  */
 
 #define xstr(s) #s
@@ -21,6 +22,7 @@
 
 static unsigned int offset;
 static unsigned int ino = 721;
+static time_t default_mtime;
 
 struct file_handler {
        const char *type;
@@ -101,8 +103,9 @@ static int cpio_mkslink(const char *name, const char *target,
                         unsigned int mode, uid_t uid, gid_t gid)
 {
        char s[256];
-       time_t mtime = time(NULL);
 
+       if (name[0] == '/')
+               name++;
        sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
               "%08X%08X%08X%08X%08X%08X%08X",
                "070701",               /* magic */
@@ -111,7 +114,7 @@ static int cpio_mkslink(const char *name, const char *target,
                (long) uid,             /* uid */
                (long) gid,             /* gid */
                1,                      /* nlink */
-               (long) mtime,           /* mtime */
+               (long) default_mtime,   /* mtime */
                (unsigned)strlen(target)+1, /* filesize */
                3,                      /* major */
                1,                      /* minor */
@@ -149,8 +152,9 @@ static int cpio_mkgeneric(const char *name, unsigned int mode,
                       uid_t uid, gid_t gid)
 {
        char s[256];
-       time_t mtime = time(NULL);
 
+       if (name[0] == '/')
+               name++;
        sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
               "%08X%08X%08X%08X%08X%08X%08X",
                "070701",               /* magic */
@@ -159,7 +163,7 @@ static int cpio_mkgeneric(const char *name, unsigned int mode,
                (long) uid,             /* uid */
                (long) gid,             /* gid */
                2,                      /* nlink */
-               (long) mtime,           /* mtime */
+               (long) default_mtime,   /* mtime */
                0,                      /* filesize */
                3,                      /* major */
                1,                      /* minor */
@@ -237,13 +241,14 @@ static int cpio_mknod(const char *name, unsigned int mode,
                       unsigned int maj, unsigned int min)
 {
        char s[256];
-       time_t mtime = time(NULL);
 
        if (dev_type == 'b')
                mode |= S_IFBLK;
        else
                mode |= S_IFCHR;
 
+       if (name[0] == '/')
+               name++;
        sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
               "%08X%08X%08X%08X%08X%08X%08X",
                "070701",               /* magic */
@@ -252,7 +257,7 @@ static int cpio_mknod(const char *name, unsigned int mode,
                (long) uid,             /* uid */
                (long) gid,             /* gid */
                1,                      /* nlink */
-               (long) mtime,           /* mtime */
+               (long) default_mtime,   /* mtime */
                0,                      /* filesize */
                3,                      /* major */
                1,                      /* minor */
@@ -286,31 +291,34 @@ static int cpio_mknod_line(const char *line)
        return rc;
 }
 
-/* Not marked static to keep the compiler quiet, as no one uses this yet... */
 static int cpio_mkfile(const char *name, const char *location,
-                       unsigned int mode, uid_t uid, gid_t gid)
+                       unsigned int mode, uid_t uid, gid_t gid,
+                       unsigned int nlinks)
 {
        char s[256];
        char *filebuf = NULL;
        struct stat buf;
+       long size;
        int file = -1;
        int retval;
        int rc = -1;
+       int namesize;
+       unsigned int i;
 
        mode |= S_IFREG;
 
-       retval = stat (location, &buf);
-       if (retval) {
-               fprintf (stderr, "File %s could not be located\n", location);
-               goto error;
-       }
-
        file = open (location, O_RDONLY);
        if (file < 0) {
                fprintf (stderr, "File %s could not be opened for reading\n", location);
                goto error;
        }
 
+       retval = fstat(file, &buf);
+       if (retval) {
+               fprintf(stderr, "File %s could not be stat()'ed\n", location);
+               goto error;
+       }
+
        filebuf = malloc(buf.st_size);
        if (!filebuf) {
                fprintf (stderr, "out of memory\n");
@@ -323,29 +331,46 @@ static int cpio_mkfile(const char *name, const char *location,
                goto error;
        }
 
-       sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
-              "%08X%08X%08X%08X%08X%08X%08X",
-               "070701",               /* magic */
-               ino++,                  /* ino */
-               mode,                   /* mode */
-               (long) uid,             /* uid */
-               (long) gid,             /* gid */
-               1,                      /* nlink */
-               (long) buf.st_mtime,    /* mtime */
-               (int) buf.st_size,      /* filesize */
-               3,                      /* major */
-               1,                      /* minor */
-               0,                      /* rmajor */
-               0,                      /* rminor */
-               (unsigned)strlen(name) + 1,/* namesize */
-               0);                     /* chksum */
-       push_hdr(s);
-       push_string(name);
-       push_pad();
+       size = 0;
+       for (i = 1; i <= nlinks; i++) {
+               /* data goes on last link */
+               if (i == nlinks) size = buf.st_size;
+
+               if (name[0] == '/')
+                       name++;
+               namesize = strlen(name) + 1;
+               sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
+                      "%08lX%08X%08X%08X%08X%08X%08X",
+                       "070701",               /* magic */
+                       ino,                    /* ino */
+                       mode,                   /* mode */
+                       (long) uid,             /* uid */
+                       (long) gid,             /* gid */
+                       nlinks,                 /* nlink */
+                       (long) buf.st_mtime,    /* mtime */
+                       size,                   /* filesize */
+                       3,                      /* major */
+                       1,                      /* minor */
+                       0,                      /* rmajor */
+                       0,                      /* rminor */
+                       namesize,               /* namesize */
+                       0);                     /* chksum */
+               push_hdr(s);
+               push_string(name);
+               push_pad();
+
+               if (size) {
+                       if (fwrite(filebuf, size, 1, stdout) != 1) {
+                               fprintf(stderr, "writing filebuf failed\n");
+                               goto error;
+                       }
+                       offset += size;
+                       push_pad();
+               }
 
-       fwrite(filebuf, buf.st_size, 1, stdout);
-       offset += buf.st_size;
-       push_pad();
+               name += namesize;
+       }
+       ino++;
        rc = 0;
        
 error:
@@ -354,49 +379,112 @@ error:
        return rc;
 }
 
+static char *cpio_replace_env(char *new_location)
+{
+       char expanded[PATH_MAX + 1];
+       char env_var[PATH_MAX + 1];
+       char *start;
+       char *end;
+
+       for (start = NULL; (start = strstr(new_location, "${")); ) {
+               end = strchr(start, '}');
+               if (start < end) {
+                       *env_var = *expanded = '\0';
+                       strncat(env_var, start + 2, end - start - 2);
+                       strncat(expanded, new_location, start - new_location);
+                       strncat(expanded, getenv(env_var),
+                               PATH_MAX - strlen(expanded));
+                       strncat(expanded, end + 1,
+                               PATH_MAX - strlen(expanded));
+                       strncpy(new_location, expanded, PATH_MAX);
+                       new_location[PATH_MAX] = 0;
+               } else
+                       break;
+       }
+
+       return new_location;
+}
+
+
 static int cpio_mkfile_line(const char *line)
 {
        char name[PATH_MAX + 1];
+       char *dname = NULL; /* malloc'ed buffer for hard links */
        char location[PATH_MAX + 1];
        unsigned int mode;
        int uid;
        int gid;
+       int nlinks = 1;
+       int end = 0, dname_len = 0;
        int rc = -1;
 
-       if (5 != sscanf(line, "%" str(PATH_MAX) "s %" str(PATH_MAX) "s %o %d %d", name, location, &mode, &uid, &gid)) {
+       if (5 > sscanf(line, "%" str(PATH_MAX) "s %" str(PATH_MAX)
+                               "s %o %d %d %n",
+                               name, location, &mode, &uid, &gid, &end)) {
                fprintf(stderr, "Unrecognized file format '%s'", line);
                goto fail;
        }
-       rc = cpio_mkfile(name, location, mode, uid, gid);
+       if (end && isgraph(line[end])) {
+               int len;
+               int nend;
+
+               dname = malloc(strlen(line));
+               if (!dname) {
+                       fprintf (stderr, "out of memory (%d)\n", dname_len);
+                       goto fail;
+               }
+
+               dname_len = strlen(name) + 1;
+               memcpy(dname, name, dname_len);
+
+               do {
+                       nend = 0;
+                       if (sscanf(line + end, "%" str(PATH_MAX) "s %n",
+                                       name, &nend) < 1)
+                               break;
+                       len = strlen(name) + 1;
+                       memcpy(dname + dname_len, name, len);
+                       dname_len += len;
+                       nlinks++;
+                       end += nend;
+               } while (isgraph(line[end]));
+       } else {
+               dname = name;
+       }
+       rc = cpio_mkfile(dname, cpio_replace_env(location),
+                        mode, uid, gid, nlinks);
  fail:
+       if (dname_len) free(dname);
        return rc;
 }
 
-void usage(const char *prog)
+static void usage(const char *prog)
 {
        fprintf(stderr, "Usage:\n"
-               "\t%s <cpio_list>\n"
+               "\t%s [-t <timestamp>] <cpio_list>\n"
                "\n"
                "<cpio_list> is a file containing newline separated entries that\n"
                "describe the files to be included in the initramfs archive:\n"
                "\n"
                "# a comment\n"
-               "file <name> <location> <mode> <uid> <gid>\n"
+               "file <name> <location> <mode> <uid> <gid> [<hard links>]\n"
                "dir <name> <mode> <uid> <gid>\n"
                "nod <name> <mode> <uid> <gid> <dev_type> <maj> <min>\n"
                "slink <name> <target> <mode> <uid> <gid>\n"
                "pipe <name> <mode> <uid> <gid>\n"
                "sock <name> <mode> <uid> <gid>\n"
                "\n"
-               "<name>      name of the file/dir/nod/etc in the archive\n"
-               "<location>  location of the file in the current filesystem\n"
-               "<target>    link target\n"
-               "<mode>      mode/permissions of the file\n"
-               "<uid>       user id (0=root)\n"
-               "<gid>       group id (0=root)\n"
-               "<dev_type>  device type (b=block, c=character)\n"
-               "<maj>       major number of nod\n"
-               "<min>       minor number of nod\n"
+               "<name>       name of the file/dir/nod/etc in the archive\n"
+               "<location>   location of the file in the current filesystem\n"
+               "             expands shell variables quoted with ${}\n"
+               "<target>     link target\n"
+               "<mode>       mode/permissions of the file\n"
+               "<uid>        user id (0=root)\n"
+               "<gid>        group id (0=root)\n"
+               "<dev_type>   device type (b=block, c=character)\n"
+               "<maj>        major number of nod\n"
+               "<min>        minor number of nod\n"
+               "<hard links> space separated list of other links to file\n"
                "\n"
                "example:\n"
                "# A simple initramfs\n"
@@ -404,7 +492,11 @@ void usage(const char *prog)
                "nod /dev/console 0600 0 0 c 5 1\n"
                "dir /root 0700 0 0\n"
                "dir /sbin 0755 0 0\n"
-               "file /sbin/kinit /usr/src/klibc/kinit/kinit 0755 0 0\n",
+               "file /sbin/kinit /usr/src/klibc/kinit/kinit 0755 0 0\n"
+               "\n"
+               "<timestamp> is time in seconds since Epoch that will be used\n"
+               "as mtime for symlinks, special files and directories. The default\n"
+               "is to use the current time for these entries.\n",
                prog);
 }
 
@@ -442,15 +534,42 @@ int main (int argc, char *argv[])
        char *args, *type;
        int ec = 0;
        int line_nr = 0;
+       const char *filename;
+
+       default_mtime = time(NULL);
+       while (1) {
+               int opt = getopt(argc, argv, "t:h");
+               char *invalid;
+
+               if (opt == -1)
+                       break;
+               switch (opt) {
+               case 't':
+                       default_mtime = strtol(optarg, &invalid, 10);
+                       if (!*optarg || *invalid) {
+                               fprintf(stderr, "Invalid timestamp: %s\n",
+                                               optarg);
+                               usage(argv[0]);
+                               exit(1);
+                       }
+                       break;
+               case 'h':
+               case '?':
+                       usage(argv[0]);
+                       exit(opt == 'h' ? 0 : 1);
+               }
+       }
 
-       if (2 != argc) {
+       if (argc - optind != 1) {
                usage(argv[0]);
                exit(1);
        }
-
-       if (! (cpio_list = fopen(argv[1], "r"))) {
+       filename = argv[optind];
+       if (!strcmp(filename, "-"))
+               cpio_list = stdin;
+       else if (!(cpio_list = fopen(filename, "r"))) {
                fprintf(stderr, "ERROR: unable to open '%s': %s\n\n",
-                       argv[1], strerror(errno));
+                       filename, strerror(errno));
                usage(argv[0]);
                exit(1);
        }
@@ -471,6 +590,7 @@ int main (int argc, char *argv[])
                                "ERROR: incorrect format, could not locate file type line %d: '%s'\n",
                                line_nr, line);
                        ec = -1;
+                       break;
                }
 
                if ('\n' == *type) {
@@ -506,7 +626,8 @@ int main (int argc, char *argv[])
                                line_nr, line);
                }
        }
-       cpio_trailer();
+       if (ec == 0)
+               cpio_trailer();
 
        exit(ec);
 }