[src/trunk]: src/usr.bin/gzip GNU gzip compatibility: don't let "gzip -dc" (z...

[mrg <mrg%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b8c6fcd3553e
branches:  trunk
changeset: 556827:b8c6fcd3553e
user:      mrg <mrg%NetBSD.org@localhost>
date:      Sun Dec 28 13:42:28 2003 +0000

description:
GNU gzip compatibility: don't let "gzip -dc" (zcat) operate on non-gzip
files by default.  -f must be used.

diffstat:

 usr.bin/gzip/gzip.c |  112 ++++++++++++++++++++++++++++++---------------------
 1 files changed, 66 insertions(+), 46 deletions(-)

diffs (171 lines):

diff -r 36141d1c66a6 -r b8c6fcd3553e usr.bin/gzip/gzip.c
--- a/usr.bin/gzip/gzip.c       Sun Dec 28 13:40:56 2003 +0000
+++ b/usr.bin/gzip/gzip.c       Sun Dec 28 13:42:28 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: gzip.c,v 1.8 2003/12/26 15:15:49 mrg Exp $     */
+/*     $NetBSD: gzip.c,v 1.9 2003/12/28 13:42:28 mrg Exp $     */
 
 /*
  * Copyright (c) 1997, 1998, 2003 Matthew R. Green
@@ -32,7 +32,7 @@
 #ifndef lint
 __COPYRIGHT("@(#) Copyright (c) 1997, 1998, 2003 Matthew R. Green\n\
      All rights reserved.\n");
-__RCSID("$NetBSD: gzip.c,v 1.8 2003/12/26 15:15:49 mrg Exp $");
+__RCSID("$NetBSD: gzip.c,v 1.9 2003/12/28 13:42:28 mrg Exp $");
 #endif /* not lint */
 
 /*
@@ -68,7 +68,10 @@
 
 #define BUFLEN 4096
 
-#define ORIG_NAME 0x08
+#define GZIP_MAGIC0    0x1F
+#define GZIP_MAGIC1    0x2B
+
+#define ORIG_NAME      0x08
 
 /* Define this if you have the NetBSD gzopenfull(3) extension to zlib(3) */
 #define HAVE_ZLIB_GZOPENFULL 0
@@ -93,6 +96,7 @@
 static char    *infile;                /* name of file coming in */
 
 static void    maybe_err(int rv, const char *fmt, ...);
+static void    maybe_errx(int rv, const char *fmt, ...);
 static void    maybe_warn(const char *fmt, ...);
 static void    maybe_warnx(const char *fmt, ...);
 static void    usage(void);
@@ -279,6 +283,20 @@
        exit(rv);
 }
 
+/* maybe print a warning */
+void
+maybe_errx(int rv, const char *fmt, ...)
+{
+       va_list ap;
+
+       if (qflag == 0) {
+               va_start(ap, fmt);
+               vwarnx(fmt, ap);
+               va_end(ap);
+       }
+       exit(rv);
+}
+
 /* compress input to output then close both files */
 static void
 gz_compress(FILE *in, gzFile out)
@@ -485,6 +503,8 @@
        gzFile in;
        off_t size;
        ssize_t len = strlen(file);
+       int fd;
+       unsigned char header1[10], name[PATH_MAX + 1];
 
        if (cflag == 0 || lflag) {
                s = &file[len - suffix_len + 1];
@@ -493,59 +513,59 @@
                        outfile[len - suffix_len + 1] = '\0';
                } else
                        maybe_err(1, "unknown suffix %s", s);
+       }
 
-               /* gather the old name info */
-               if (Nflag || lflag) {
-                       int fd;
-                       unsigned char header1[10], name[PATH_MAX + 1];
+       /* gather the old name info */
 
-                       fd = open(file, O_RDONLY);
-                       if (fd < 0)
-                               maybe_err(1, "can't open %s", file);
-                       if (read(fd, header1, 10) != 10)
-                               maybe_err(1, "can't read %s", file);
+       fd = open(file, O_RDONLY);
+       if (fd < 0)
+               maybe_err(1, "can't open %s", file);
+       if (read(fd, header1, 10) != 10)
+               maybe_err(1, "can't read %s", file);
 
-                       if (header1[3] & ORIG_NAME) {
-                               size_t rbytes;
-                               int i;
+       if (fflag == 0 &&
+           (header1[0] != GZIP_MAGIC0 || header1[1] != GZIP_MAGIC1))
+               maybe_errx(1, "%s: not in gzip format", file);
 
-                               rbytes = read(fd, name, PATH_MAX + 1);
-                               if (rbytes < 0)
-                                       maybe_err(1, "can't read %s", file);
-                               for (i = 0; i < rbytes && name[i]; i++)
-                                       ;
-                               if (i < rbytes) {
-                                       name[i] = 0;
-                                       /* now maybe merge old dirname */
-                                       if (strchr(outfile, '/') == 0)
-                                               outfile = name;
-                                       else {
-                                               char *dir = dirname(outfile);
-                                               if (asprintf(&outfile, "%s/%s",
-                                                   dir, name) == -1)
-                                                       maybe_err(1, "malloc");
-                                       }
+       if (Nflag || lflag) {
+               if (header1[3] & ORIG_NAME) {
+                       size_t rbytes;
+                       int i;
+
+                       rbytes = read(fd, name, PATH_MAX + 1);
+                       if (rbytes < 0)
+                               maybe_err(1, "can't read %s", file);
+                       for (i = 0; i < rbytes && name[i]; i++)
+                               ;
+                       if (i < rbytes) {
+                               name[i] = 0;
+                               /* now maybe merge old dirname */
+                               if (strchr(outfile, '/') == 0)
+                                       outfile = name;
+                               else {
+                                       char *dir = dirname(outfile);
+                                       if (asprintf(&outfile, "%s/%s", dir,
+                                           name) == -1)
+                                               maybe_err(1, "malloc");
                                }
                        }
-                       close(fd);
                }
+       }
+       close(fd);
 
-               if (fflag == 0) {
-                       if (lflag == 0 && stat(outfile, &osb) == 0) {
-                               maybe_warnx("%s already exists -- skipping",
-                                           outfile);
+       if ((cflag == 0 || lflag) && fflag == 0) {
+               if (lflag == 0 && stat(outfile, &osb) == 0) {
+                       maybe_warnx("%s already exists -- skipping", outfile);
+                       goto lose;
+               }
+               if (stat(file, &isb) == 0) {
+                       if (isb.st_nlink > 1 && lflag == 0) {
+                               maybe_warnx("%s has %d other links -- skipping",
+                                   file, isb.st_nlink - 1);
                                goto lose;
                        }
-                       if (stat(file, &isb) == 0) {
-                               if (isb.st_nlink > 1 && lflag == 0) {
-                                       maybe_warnx("%s has %d other link%s -- "
-                                           "skipping", file, isb.st_nlink-1,
-                                           isb.st_nlink == 1 ? "" : "s");
-                                       goto lose;
-                               }
-                       } else
-                               goto lose;
-               }
+               } else
+                       goto lose;
        }
 
        if (lflag) {