gzip -l: account for multiple streams

[Todd C. Miller]

Currently, the info in "gzip -l" only accounts for the last stream
in the file.  For example:

$ gzip.old -l valgrind-3.10.1p9.tgz
compressed  uncompressed  ratio  uncompressed_name
   2122549       9048576  76.5%  valgrind-3.10.1p9.tar

$ gzip.new -l /usr/ports/packages/amd64/all/valgrind-3.10.1p9.tgz
compressed  uncompressed  ratio  uncompressed_name
  27988837      81453568  65.6%  valgrind-3.10.1p9.tar

$ ls -l valgrind-3.10.1p9.tgz
-rw-r--r--  3 millert  staff  27988837 Mar 29 10:09 valgrind-3.10.1p9.tgz

$ gunzip -c valgrind-3.10.1p9.tgz | wc -c
 81453568

Index: usr.bin/compress/gzopen.c
===================================================================
RCS file: /cvs/src/usr.bin/compress/gzopen.c,v
retrieving revision 1.29
diff -u -p -u -r1.29 gzopen.c
--- usr.bin/compress/gzopen.c   20 Aug 2015 22:32:41 -0000      1.29
+++ usr.bin/compress/gzopen.c   27 Apr 2016 20:34:20 -0000
@@ -83,14 +83,15 @@
 typedef
 struct gz_stream {
        int     z_fd;           /* .gz file */
-       z_stream z_stream;      /* libz stream */
        int     z_eof;          /* set if end of input file */
+       z_stream z_stream;      /* libz stream */
        u_char  z_buf[Z_BUFSIZE]; /* i/o buffer */
+       char    z_mode;         /* 'w' or 'r' */
        u_int32_t z_time;       /* timestamp (mtime) */
-       u_int32_t z_hlen;       /* length of the gz header */
        u_int32_t z_crc;        /* crc32 of uncompressed data */
-       char    z_mode;         /* 'w' or 'r' */
-
+       u_int32_t z_hlen;       /* length of the gz header */
+       u_int64_t z_total_in;   /* # bytes in */
+       u_int64_t z_total_out;  /* # bytes out */
 } gz_stream;
 
 static const u_char gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
@@ -128,6 +129,8 @@ gz_open(int fd, const char *mode, char *
        s->z_eof = 0;
        s->z_time = 0;
        s->z_hlen = 0;
+       s->z_total_in = 0;
+       s->z_total_out = 0;
        s->z_crc = crc32(0L, Z_NULL, 0);
        s->z_mode = mode[0];
 
@@ -206,8 +209,8 @@ gz_close(void *cookie, struct z_info *in
                info->mtime = s->z_time;
                info->crc = s->z_crc;
                info->hlen = s->z_hlen;
-               info->total_in = (off_t)s->z_stream.total_in;
-               info->total_out = (off_t)s->z_stream.total_out;
+               info->total_in = s->z_total_in;
+               info->total_out = s->z_total_out;
        }
 
        setfile(name, s->z_fd, sb);
@@ -336,7 +339,7 @@ get_header(gz_stream *s, char *name, int
        (void)get_byte(s);
        (void)get_byte(s);
 
-       s->z_hlen = 10; /* magic, method, flags, time, xflags, OS code */
+       s->z_hlen += 10; /* magic, method, flags, time, xflags, OS code */
        if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
                len  =  (uInt)get_byte(s);
                len += ((uInt)get_byte(s))<<8;
@@ -438,11 +441,11 @@ gz_read(void *cookie, char *buf, int len
 
                if (error == Z_DATA_ERROR) {
                        errno = EINVAL;
-                       return -1;
+                       goto bad;
                }
                if (error == Z_BUF_ERROR) {
                        errno = EIO;
-                       return -1;
+                       goto bad;
                }
                if (error == Z_STREAM_END) {
                        /* Check CRC and original size */
@@ -452,13 +455,18 @@ gz_read(void *cookie, char *buf, int len
 
                        if (get_int32(s) != s->z_crc) {
                                errno = EINVAL;
-                               return -1;
+                               goto bad;
                        }
                        if (get_int32(s) != (u_int32_t)s->z_stream.total_out) {
                                errno = EIO;
                                return -1;
                        }
                        s->z_hlen += 2 * sizeof(int32_t);
+
+                       /* Add byte counts from the finished stream. */
+                       s->z_total_in += s->z_stream.total_in;
+                       s->z_total_out += s->z_stream.total_out;
+
                        /* Check for the existence of an appended file. */
                        if (get_header(s, NULL, 0) != 0) {
                                s->z_eof = 1;
@@ -474,6 +482,11 @@ gz_read(void *cookie, char *buf, int len
        len -= s->z_stream.avail_out;
 
        return (len);
+bad:
+       /* Add byte counts from the finished stream. */
+       s->z_total_in += s->z_stream.total_in;
+       s->z_total_out += s->z_stream.total_out;
+       return (-1);
 }
 
 int