Add uninstall directive to manifest

Allows for removal of old files or packages

seed/script-generator.c

@@ -11,7 +11,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <bootstrappable.h>
 
 struct Token {
 	char *val;
@@ -23,6 +22,7 @@ typedef struct Token Token;
 #define TYPE_IMPROVE 2
 #define TYPE_DEFINE 3
 #define TYPE_JUMP 4
+#define TYPE_UNINSTALL 5
 
 struct Directive {
 	Token *tok;
@@ -212,12 +212,12 @@ Token *fill(Token *tok, Directive *directive, int type) {
 
 Token *logic(Token *tok, char **val) {
 	/* logic = "("
-	 *         (name |
-	 *         (name "==" value) |
-     *         (name "!=" value) |
-	 *         (logic "||" logic) |
-	 *         (logic "&&" logic))
-	 *         ")"
+	 *	 (name |
+	 *	 (name "==" value) |
+	 *	 (name "!=" value) |
+	 *	 (logic "||" logic) |
+	 *	 (logic "&&" logic))
+	 *	 ")"
 	 */
 
 	char *lhs = tok->val;
@@ -237,15 +237,15 @@ Token *logic(Token *tok, char **val) {
 			lhs = "False";
 		}
 	} else if (strcmp(tok->val, "!=") == 0) {
-                /* Case for inequality. */
-                rhs = tok->next->val;
-                tok = tok->next->next;
-                if (strcmp(get_var(lhs), rhs) == 0) {
-                        lhs = "False";
-                } else {
-                        lhs = "True";
-                }
-        } else {
+		/* Case for inequality. */
+		rhs = tok->next->val;
+		tok = tok->next->next;
+		if (strcmp(get_var(lhs), rhs) == 0) {
+			lhs = "False";
+		} else {
+			lhs = "True";
+		}
+	} else {
 		fputs("Expected == or != after ", stderr);
 		fputs(lhs, stderr);
 		fputs(" in logic\n", stderr);
@@ -360,7 +360,7 @@ Token *define(Token *tok, Directive *directive) {
 }
 
 int interpret(Directive *directive) {
-	/* directive = (build | improve | define | jump) predicate? */
+	/* directive = (build | improve | define | jump | uninstall) predicate? */
 	Token *tok = directive->tok;
 	if (strcmp(tok->val, "build:") == 0) {
 		tok = fill(tok->next, directive, TYPE_BUILD);
@@ -371,6 +371,20 @@ int interpret(Directive *directive) {
 	} else if (strcmp(tok->val, "define:") == 0) {
 		tok = define(tok->next, directive);
 		return 1; /* There is no codegen for a define. */
+	} else if (strcmp(tok->val, "uninstall:") == 0) {
+		tok = fill(tok->next, directive, TYPE_UNINSTALL);
+		while (tok != NULL) {
+			if (strcmp(tok->val, "(") == 0) {
+				break;
+			}
+			if (strlen(directive->arg) + strlen(tok->val) + 1 > MAX_STRING) {
+				fputs("somehow you have managed to have too many uninstall arguments.\n", stderr);
+				exit(1);
+			}
+			directive->arg = strcat(directive->arg, " ");
+			directive->arg = strcat(directive->arg, tok->val);
+			tok = tok->next;
+		}
 	}
 
 	if (tok != NULL) {
@@ -618,6 +632,10 @@ void generate(Directive *directives) {
 			fclose(out);
 			out = start_script(counter, bash_build);
 			counter += 1;
+		} else if (directive->type == TYPE_UNINSTALL) {
+			fputs("uninstall ", out);
+			fputs(directive->arg, out);
+			fputs("\n", out);
 		}
 	}
 	fclose(out);

steps/helpers.sh

@@ -79,9 +79,11 @@ _grep() {
 
 get_revision() {
     local pkg=$1
+    local oldpwd="${PWD}"
     cd "/external/repo"
     # Get revision (n time this package has been built)
     revision=$( (ls -1 "${pkg}"* 2>/dev/null || true) | wc -l | sed 's/ *//g')
+    cd "${oldpwd}"
 }
 
 # Installs binary packages from an earlier run
@@ -108,6 +110,64 @@ bin_preseed() {
     return 1
 }
 
+# Removes either an existing package or file
+uninstall() {
+    local in_fs in_pkg symlinks
+    while [ $# -gt 0 ]; do
+        removing="$1"
+        case "${removing}" in
+            /*)
+                # Removing a file
+                echo "removing file: ${removing}."
+                rm -f "${removing}"
+                ;;
+            *)
+                echo "${removing}: uninstalling."
+                local oldpwd="${PWD}"
+                mkdir -p "/tmp/removing"
+                cd "/tmp/removing"
+                get_revision "${removing}"
+                local filename="/external/repo/${removing}_$((revision-1)).tar.bz2"
+                # Initial bzip2 built against meslibc has broken pipes
+                bzip2 -dc "${filename}" | tar -xf -
+                # reverse to have files before directories
+                if command -v find >/dev/null 2>&1; then
+                    find . | sort -r > ../filelist
+                else
+                    get_files . | tac > ../filelist
+                fi
+                # shellcheck disable=SC2162
+                while read file; do
+                    if [ -d "${file}" ]; then
+                        if [ -z "$(ls -A "/${file}")" ]; then
+                            rmdir "/${file}"
+                        fi
+                    else
+                        # in some cases we might be uninstalling a file that has already been overwritten
+                        # in this case we don't want to remove it
+                        in_fs="$(sha256sum "${file}" 2>/dev/null | cut -d' ' -f1)"
+                        in_pkg="$(sha256sum "/${file}" 2>/dev/null | cut -d' ' -f1)"
+                        if [ "${in_fs}" = "${in_pkg}" ]; then
+                            rm -f "/${file}"
+                        fi
+                        if [ -h "${file}" ]; then
+                            symlinks="${symlinks} ${file}"
+                        fi
+                    fi
+                done < ../filelist
+                rm -f ../filelist
+                for link in ${symlinks}; do
+                    if [ ! -e "/${link}" ]; then
+                        rm -f "/${link}"
+                    fi
+                done
+                cd "${oldpwd}"
+                ;;
+        esac
+        shift
+    done
+}
+
 # Common build steps
 # Build function provides a few common stages with default implementation
 # that can be overridden on per package basis in the build script.
@@ -236,6 +296,7 @@ extract_file() {
         *)
             case "${f}" in
                 *.tar* | *.tgz)
+                    # shellcheck disable=SC2153
                     if test -e "${PREFIX}/libexec/rmt"; then
                         # Again, we want to split out into words.
                         # shellcheck disable=SC2086

steps/manifest

@@ -15,6 +15,9 @@
 #   eg, define: BUILD_FIWIX = KERNEL_BOOTSTRAP == True || BUILD_KERNELS == True
 # - jump: jump (usually) to a new kernel, executes a script with that name
 #   eg, jump: fiwix
+# - uninstall; removes a package or filenames
+#   eg, uninstall: perl-5.6.2
+#   eg, uninstall: /usr/bin/lex /usr/bin/flex
 #
 # The following directives have special significance:
 # - build directives beginning with "bash" (as well as jumps) trigger the generation of