Resume source downloads across GNU mirrors.

download.sh

@@ -5,7 +5,8 @@ cd "$(dirname "$0")"
 cd archives || exit 1
 
 ARCHIVE="archives.txt"
-WGET="wget --tries=5 --timeout=15 --quiet --show-progress"
+# 15s was aborting slow Sourceware transfers. Keep the partial file and resume.
+WGET_OPTS=(--continue --tries=20 --timeout=60 --waitretry=5 --retry-connrefused --quiet --show-progress)
 
 # -----------------------------------------------------------------------------
 # verify_sha256 <file> <expected_sha>
@@ -29,17 +30,67 @@ verify_sha256() {
     return 0
 }
 
+file_size() {
+    wc -c "$1" | awk '{print $1}'
+}
+
 # -----------------------------------------------------------------------------
-# fetch <url> <dest>
+# mirror_urls <url>
+# Prints the primary URL plus GNU/kernel.org fallbacks.
 # -----------------------------------------------------------------------------
-fetch() {
+mirror_urls() {
     url="$1"
-    dest="$2"
-    $WGET -O "$dest" "$url" || {
-        echo "  !! Download failed: $url" >&2
-        rm -f "$dest"
-        return 1
-    }
+    file="$(basename "$url")"
+    printf '%s\n' "$url"
+
+    case "$url" in
+        */binutils/releases/*|*/gnu/binutils/*)
+            printf '%s\n' \
+                "https://ftpmirror.gnu.org/gnu/binutils/${file}" \
+                "https://ftp.gnu.org/gnu/binutils/${file}" \
+                "https://sourceware.org/pub/binutils/releases/${file}" \
+                "https://mirrors.kernel.org/sourceware/binutils/releases/${file}"
+            ;;
+        */gcc/releases/*|*/gnu/gcc/*)
+            ver="${file%.tar.*}"
+            printf '%s\n' \
+                "https://ftpmirror.gnu.org/gnu/gcc/${ver}/${file}" \
+                "https://ftp.gnu.org/gnu/gcc/${ver}/${file}" \
+                "https://sourceware.org/pub/gcc/releases/${ver}/${file}" \
+                "https://gcc.gnu.org/pub/gcc/releases/${ver}/${file}"
+            ;;
+        */gdb/releases/*|*/gnu/gdb/*)
+            printf '%s\n' \
+                "https://ftpmirror.gnu.org/gnu/gdb/${file}" \
+                "https://ftp.gnu.org/gnu/gdb/${file}" \
+                "https://sourceware.org/pub/gdb/releases/${file}"
+            ;;
+        */newlib/*)
+            printf '%s\n' \
+                "https://sourceware.org/pub/newlib/${file}" \
+                "https://mirrors.kernel.org/sourceware/newlib/${file}"
+            ;;
+    esac
+}
+
+# -----------------------------------------------------------------------------
+# fetch <dest> <url> [url...]
+# Resumes into dest; does not delete a partial file on failure.
+# -----------------------------------------------------------------------------
+fetch() {
+    dest="$1"
+    shift
+    url=""
+    for url in "$@"; do
+        [ -n "$url" ] || continue
+        echo "  -> $url"
+        if wget "${WGET_OPTS[@]}" -O "$dest" "$url"; then
+            return 0
+        fi
+        echo "  !! failed, trying next mirror..." >&2
+    done
+    echo "  !! Download failed: ${1:-$url}" >&2
+    return 1
 }
 
 # -----------------------------------------------------------------------------
@@ -54,7 +105,6 @@ download() {
 
     printf '==> %s\n' "$file"
 
-    # If already present, verify immediately — size alone is not enough.
     if [ -f "$file" ]; then
         if [ "$sha" = "-" ]; then
             echo "  -- no checksum, skipping re-download of existing file"
@@ -64,19 +114,27 @@ download() {
             echo "  -- already good"
             return 0
         fi
-        echo "  -- existing file failed verification, re-downloading..."
-        rm -f "$file"
+        actual=$(file_size "$file")
+        if [ "$size" != "-" ] && [ "$actual" -lt "$size" ]; then
+            echo "  -- incomplete (${actual}/${size} bytes), resuming..."
+        else
+            echo "  -- existing file failed verification, re-downloading..."
+            rm -f "$file"
+        fi
     fi
 
-    # First attempt
-    fetch "$url" "$file"
+    # Unique mirror list, primary URL first.
+    urls=$(mirror_urls "$url" | awk 'NF && !seen[$0]++')
+
+    # shellcheck disable=SC2086
+    fetch "$file" $urls
 
-    # Verify, with one retry on mismatch
     if [ "$sha" != "-" ]; then
         if ! verify_sha256 "$file" "$sha"; then
-            echo "  -- retrying download..."
+            echo "  -- checksum failed, retrying from another mirror..."
             rm -f "$file"
-            fetch "$url" "$file"
+            # shellcheck disable=SC2086
+            fetch "$file" $urls
             verify_sha256 "$file" "$sha" || {
                 rm -f "$file"
                 echo "  !! Giving up on $file" >&2
@@ -125,6 +183,7 @@ run_one() {
     found=0
     while IFS= read -r line; do
         case "$line" in
+            \#*|"") continue ;;
             *"$target"*) ;;
             *) continue ;;
         esac
@@ -138,6 +197,7 @@ EOF
     done < "$ARCHIVE"
     [ "$found" -eq 1 ] || {
         echo "Not found: $target" >&2
+        echo "Add a line to archives/archives.txt, including the SHA256." >&2
         exit 1
     }
 }
@@ -147,4 +207,4 @@ if [ "$#" -eq 0 ]; then
     run_all
 else
     run_one "$1"
-fi
+fi