Implement export table parsing.

diff --git a/libupkg.c b/libupkg.c
index de4b2f107f09d7d717cf69c8ca8f7d2d82bb2120..f55c079a447020d7657f68b150846fca4057d876 100644 (file)
--- a/libupkg.c
+++ b/libupkg.c
@@ -5,31 +5,63 @@
 #include "upkg.h"
 #include "pack.h"
 
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
 struct upkg_name {
        unsigned long flags;
        char *name;
 };
 
+struct upkg_export {
+       long class, super, name;
+       unsigned long package, flags;
+       unsigned long size, offset;
+};
+
 struct upkg_private {
        FILE *f;
 
-       struct upkg_name *names;
+       struct upkg_name   *names;
+       struct upkg_export *exports;
 
        unsigned long name_offset, export_offset, import_offset;
        unsigned char guid[16];
 };
 
-static long decode_index(unsigned char *bytes)
+/*
+ * Decode the compact index format from the upkg.  This format is fucked.
+ * Stores the result in *val and returns the number of input bytes read (or 0
+ * if the input is invalid, in which case *val is undefined).
+ */
+static size_t decode_index(long *val, unsigned char *bytes, size_t n)
 {
-       long val = 0;
-       size_t i = 1;
+       size_t i = 0;
+
+       *val = 0;
+       while (i < MIN(n, 5)) {
+               /*
+                * Least significant bytes are first, so we need to do this
+                * nonsense.
+                */
+               long tmp = bytes[i] & (i == 0 ? 0x3f : 0x7f);
+
+               if (i > 0) tmp <<= 6;
+               if (i > 1) tmp <<= 7*(i-1);
+               *val += tmp;
+
+               if (!(bytes[i] & (i == 0 ? 0x40 : 0x80))) {
+                       i++;
+                       break;
+               }
 
-       val += bytes[0] & 0x3f;
-       if (bytes[0] & 0x40) do {
-               val += bytes[i] & 0x7f;
-       } while (bytes[i] & 0x80 && i < 5);
+               i++;
+       }
 
-       return bytes[0] & 0x80 ? -val : val;
+       if (i > MIN(n, 5) || n == 0)
+               return 0;
+       if (bytes[0] & 0x80)
+               *val = -*val;
+       return i;
 }
 
 static struct upkg *init_upkg(unsigned char hdr[static UPKG_HDR_SIZE])
@@ -112,6 +144,72 @@ err:
        return -1;
 }
 
+static int pkg_init_exports(struct upkg *pkg)
+{
+       size_t rc, len, nbuf = 0;
+       unsigned long index = 0;
+       char buf[512];
+
+       if (fseek(pkg->priv->f, pkg->priv->export_offset, SEEK_SET) != 0)
+               return -1;
+
+       pkg->priv->exports = malloc(pkg->export_count * sizeof *pkg->priv->exports);
+       if (!pkg->priv->exports)
+               return -1;
+
+       while (index < pkg->export_count) {
+               struct upkg_export *export = &pkg->priv->exports[index];
+
+               /* Read some data into buffer. */
+               if (!feof(pkg->priv->f)) {
+                       rc = fread(buf+nbuf, 1, sizeof buf-nbuf, pkg->priv->f);
+                       if (rc == 0)
+                               goto err;
+                       nbuf += rc;
+               }
+
+               len = 0;
+               rc = decode_index(&export->class, buf+len, nbuf-len);
+               if (rc == 0) goto err;
+               len += rc;
+
+               rc = decode_index(&export->super, buf+len, nbuf-len);
+               if (rc == 0) goto err;
+               len += rc;
+
+               if (nbuf-len < 4) goto err;
+               export->package = unpack_32_le(buf+len);
+               len += 4;
+
+               rc = decode_index(&export->name, buf+len, nbuf-len);
+               if (rc == 0) goto err;
+               len += rc;
+
+               if (nbuf-len < 4) goto err;
+               export->flags = unpack_32_le(buf+len);
+               len += 4;
+
+               rc = decode_index(&export->size, buf+len, nbuf-len);
+               if (rc == 0) goto err;
+               len += rc;
+
+               if (export->size) {
+                       rc = decode_index(&export->offset, buf+len, nbuf-len);
+                       if (rc == 0) goto err;
+                       len += rc;
+               }
+
+               nbuf -= len;
+               memmove(buf, buf+len, nbuf);
+               index++;
+       }
+
+       return 0;
+err:
+       free(pkg->priv->exports);
+       return -1;
+}
+
 struct upkg *upkg_fopen(const char *path)
 {
        unsigned char hdr_buf[UPKG_HDR_SIZE];
@@ -135,11 +233,17 @@ struct upkg *upkg_fopen(const char *path)
        }
        pkg->priv->f = f;
 
-       if (pkg_init_names(pkg) != 0) {
+       if (pkg_init_exports(pkg) != 0) {
                goto err2;
        }
 
+       if (pkg_init_names(pkg) != 0) {
+               goto err3;
+       }
+
        return pkg;
+err3:
+       free(pkg->priv->exports);
 err2:
        free(pkg->priv);
        free(pkg);
@@ -158,11 +262,12 @@ int upkg_close(struct upkg *pkg)
                for (unsigned i = 0; i < pkg->name_count; i++) {
                        free(pkg->priv->names[i].name);
                }
-               free(pkg->priv->names);
 
                return rc;
        }
 
+       free(pkg->priv->exports);
+       free(pkg->priv->names);
        free(pkg->priv);
        free(pkg);
 

diff --git a/upkg.c b/upkg.c
index d7b181de515d08b8135b98acebd3cdc62219c301..2694f5b20a2bb1ed33c61ea989013b7f404703bd 100644 (file)
--- a/upkg.c
+++ b/upkg.c
@@ -45,6 +45,8 @@ int main(int argc, char **argv)
                printf("\t%s\n", upkg_get_name(pkg, i));
        }
 
+       printf("Exports: %lu\n", pkg->export_count);
+
        upkg_close(pkg);
        return 0;
 }