contrib/untar.c: cleanup (#2112)

This reworks PR #1613 (commit a902fcd4), addressing the same issues as that
earlier PR, but in a simpler and more portable fashion.

Co-authored-by: Martin Matuška <martin@matuska.org>

diff --git a/contrib/untar.c b/contrib/untar.c
index db25118869108f9029540c9a6503b2b7d749086c..6d5e88e2f097c8306c1a6ae625f30373f32e660b 100644 (file)
--- a/contrib/untar.c
+++ b/contrib/untar.c
@@ -37,22 +37,28 @@
 #include <sys/stat.h>  /* For mkdir() */
 
 #if defined(_WIN32) && !defined(__CYGWIN__)
-#define NUM_FORMAT "zu"
-#include <direct.h>
-#elif defined(__linux__) || defined(linux) || defined(__linux)
-#define NUM_FORMAT "d"
-#else
-#define NUM_FORMAT "lu"
-#endif /* defined(_WIN32) && !defined(__CYGWIN__) */
+#include <windows.h>
+#endif
 
-#define TO_STRING(x) #x
-#define STR(x) TO_STRING(x)
+#define BLOCKSIZE 512
 
-/* Parse an octal number, ignoring leading and trailing nonsense. */
+/* System call to create a directory. */
 static int
+system_mkdir(char *pathname, int mode)
+{
+#if defined(_WIN32) && !defined(__CYGWIN__)
+       (void)mode; /* UNUSED */
+       return _mkdir(pathname);
+#else
+       return mkdir(pathname, mode);
+#endif
+}
+
+/* Parse an octal number, ignoring leading and trailing nonsense. */
+static unsigned long
 parseoct(const char *p, size_t n)
 {
-       int i = 0;
+       unsigned long i = 0;
 
        while ((*p < '0' || *p > '7') && n > 0) {
                ++p;
@@ -72,7 +78,7 @@ static int
 is_end_of_archive(const char *p)
 {
        int n;
-       for (n = 511; n >= 0; --n)
+       for (n = 0; n < BLOCKSIZE; ++n)
                if (p[n] != '\0')
                        return (0);
        return (1);
@@ -90,12 +96,7 @@ create_dir(char *pathname, int mode)
                pathname[strlen(pathname) - 1] = '\0';
 
        /* Try creating the directory. */
-#if defined(_WIN32) && !defined(__CYGWIN__)
-       r = _mkdir(pathname);
-#else
-       r = mkdir(pathname, mode);
-#endif
-
+       r = system_mkdir(pathname, mode);
        if (r != 0) {
                /* On failure, try creating parent directory. */
                p = strrchr(pathname, '/');
@@ -103,11 +104,7 @@ create_dir(char *pathname, int mode)
                        *p = '\0';
                        create_dir(pathname, 0755);
                        *p = '/';
-#if defined(_WIN32) && !defined(__CYGWIN__)
-                       r = _mkdir(pathname);
-#else
-                       r = mkdir(pathname, mode);
-#endif
+                       r = system_mkdir(pathname, mode);
                }
        }
        if (r != 0)
@@ -138,7 +135,7 @@ static int
 verify_checksum(const char *p)
 {
        int n, u = 0;
-       for (n = 0; n < 512; ++n) {
+       for (n = 0; n < BLOCKSIZE; ++n) {
                if (n < 148 || n > 155)
                        /* Standard tar checksum adds unsigned bytes. */
                        u += ((unsigned char *)p)[n];
@@ -146,26 +143,25 @@ verify_checksum(const char *p)
                        u += 0x20;
 
        }
-       return (u == parseoct(p + 148, 8));
+       return (u == (int)parseoct(p + 148, 8));
 }
 
 /* Extract a tar archive. */
 static void
 untar(FILE *a, const char *path)
 {
-    enum { BUF_SIZE=512 };
-       char buff[BUF_SIZE];
+       char buff[BLOCKSIZE];
        FILE *f = NULL;
        size_t bytes_read;
-       off_t filesize;
+       unsigned long filesize;
 
        printf("Extracting from %s\n", path);
        for (;;) {
-               bytes_read = fread(buff, 1, BUF_SIZE, a);
-               if (bytes_read < BUF_SIZE) {
+               bytes_read = fread(buff, 1, BLOCKSIZE, a);
+               if (bytes_read < BLOCKSIZE) {
                        fprintf(stderr,
-                                       "Short read on %s: expected " STR(BUF_SIZE) ", got %"NUM_FORMAT"\n",
-                                       path, bytes_read);
+                           "Short read on %s: expected %d, got %d\n",
+                           path, BLOCKSIZE, (int)bytes_read);
                        return;
                }
                if (is_end_of_archive(buff)) {
@@ -178,51 +174,51 @@ untar(FILE *a, const char *path)
                }
                filesize = parseoct(buff + 124, 12);
                switch (buff[156]) {
-                       case '1':
-                               printf(" Ignoring hardlink %s\n", buff);
-                               break;
-                       case '2':
-                               printf(" Ignoring symlink %s\n", buff);
-                               break;
-                       case '3':
-                               printf(" Ignoring character device %s\n", buff);
-                               break;
-                       case '4':
-                               printf(" Ignoring block device %s\n", buff);
-                               break;
-                       case '5':
-                               printf(" Extracting dir %s\n", buff);
-                               create_dir(buff, parseoct(buff + 100, 8));
-                               filesize = 0;
-                               break;
-                       case '6':
-                               printf(" Ignoring FIFO %s\n", buff);
-                               break;
-                       default:
-                               printf(" Extracting file %s\n", buff);
-                               f = create_file(buff, parseoct(buff + 100, 8));
+               case '1':
+                       printf(" Ignoring hardlink %s\n", buff);
+                       break;
+               case '2':
+                       printf(" Ignoring symlink %s\n", buff);
+                       break;
+               case '3':
+                       printf(" Ignoring character device %s\n", buff);
                                break;
+               case '4':
+                       printf(" Ignoring block device %s\n", buff);
+                       break;
+               case '5':
+                       printf(" Extracting dir %s\n", buff);
+                       create_dir(buff, (int)parseoct(buff + 100, 8));
+                       filesize = 0;
+                       break;
+               case '6':
+                       printf(" Ignoring FIFO %s\n", buff);
+                       break;
+               default:
+                       printf(" Extracting file %s\n", buff);
+                       f = create_file(buff, (int)parseoct(buff + 100, 8));
+                       break;
                }
                while (filesize > 0) {
-                       bytes_read = fread(buff, 1, BUF_SIZE, a);
-                       if (bytes_read < BUF_SIZE) {
+                       bytes_read = fread(buff, 1, BLOCKSIZE, a);
+                       if (bytes_read < BLOCKSIZE) {
                                fprintf(stderr,
-                                               "Short read on %s: Expected " STR(BUF_SIZE) ", got %"NUM_FORMAT"\n",
-                                               path, bytes_read);
+                                   "Short read on %s: Expected %d, got %d\n",
+                                   path, BLOCKSIZE, (int)bytes_read);
                                return;
                        }
-                       if (filesize < BUF_SIZE)
-                               bytes_read = filesize;
+                       if (filesize < BLOCKSIZE)
+                               bytes_read = (size_t)filesize;
                        if (f != NULL) {
                                if (fwrite(buff, 1, bytes_read, f)
-                                       != bytes_read)
+                                   != bytes_read)
                                {
                                        fprintf(stderr, "Failed write\n");
                                        fclose(f);
                                        f = NULL;
                                }
                        }
-                       filesize -= (off_t)bytes_read;
+                       filesize -= bytes_read;
                }
                if (f != NULL) {
                        fclose(f);