gen_init_cpio: avoid stack overflow when expanding
[linux-3.10.git] / usr / gen_init_cpio.c
index b2b3c2d..aca6edc 100644 (file)
@@ -22,6 +22,7 @@
 
 static unsigned int offset;
 static unsigned int ino = 721;
+static time_t default_mtime;
 
 struct file_handler {
        const char *type;
@@ -102,8 +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 */
@@ -112,7 +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 */
@@ -150,8 +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 */
@@ -160,7 +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 */
@@ -238,13 +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 */
@@ -253,7 +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 */
@@ -299,22 +303,22 @@ static int cpio_mkfile(const char *name, const char *location,
        int retval;
        int rc = -1;
        int namesize;
-       int i;
+       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");
@@ -332,6 +336,8 @@ static int cpio_mkfile(const char *name, const char *location,
                /* 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",
@@ -375,25 +381,28 @@ error:
 
 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, "${")); ) {
-               end = strchr(start, '}');
-               if (start < end) {
-                       *env_var = *expanded = '\0';
-                       strncat(env_var, start + 2, end - start - 2);
-                       strncat(expanded, new_location, start - new_location);
-                       strncat(expanded, getenv(env_var), PATH_MAX);
-                       strncat(expanded, end + 1, PATH_MAX);
-                       strncpy(new_location, expanded, PATH_MAX);
-               } else
-                       break;
-       }
-
-       return new_location;
+       char expanded[PATH_MAX + 1];
+       char env_var[PATH_MAX + 1];
+       char *start;
+       char *end;
+
+       for (start = NULL; (start = strstr(new_location, "${")); ) {
+               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;
 }
 
 
@@ -452,7 +461,7 @@ static int cpio_mkfile_line(const char *line)
 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"
@@ -483,7 +492,11 @@ static 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);
 }
 
@@ -521,17 +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 (!strcmp(argv[1], "-"))
+       filename = argv[optind];
+       if (!strcmp(filename, "-"))
                cpio_list = stdin;
-       else if (! (cpio_list = fopen(argv[1], "r"))) {
+       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);
        }