pacman: add -Q --backup

pacman -Q -w/--backup will print the modified backup files of a system
(passing twice will print all backup files). This could be useful for
backup/moving system config files.

doc/pacman.8.asciidoc

@@ -364,6 +364,9 @@ Query Options (apply to '-Q')[[QO]]
 	replacements are not checked here. This option works best if the sync
 	database is refreshed using '-Sy'.
 
+*-w, \--backup*::
+	List all modified backup files owened by a given package. Multiple packages can
+	be specified on the command line. Pass twice to print all backup files.
 
 Remove Options (apply to '-R')[[RO]]
 ------------------------------------

src/pacman/conf.h

@@ -83,6 +83,7 @@ typedef struct __config_t {
 	unsigned short op_q_upgrade;
 	unsigned short op_q_check;
 	unsigned short op_q_locality;
+	unsigned short op_q_backup;
 
 	unsigned short op_s_clean;
 	unsigned short op_s_downloadonly;
@@ -180,6 +181,7 @@ enum {
 	OP_DBPATH,
 	OP_CASCADE,
 	OP_CHANGELOG,
+	OP_BACKUP,
 	OP_CLEAN,
 	OP_NODEPS,
 	OP_DEPS,

src/pacman/package.c

@@ -348,7 +348,7 @@ void dump_pkg_full(alpm_pkg_t *pkg, int extra)
 
 	/* Print additional package info if info flag passed more than once */
 	if(from == ALPM_PKG_FROM_LOCALDB && extra) {
-		dump_pkg_backups(pkg);
+		dump_backup_status(pkg);
 	}
 
 	/* final newline to separate packages */
@@ -359,6 +359,34 @@ void dump_pkg_full(alpm_pkg_t *pkg, int extra)
 	alpm_list_free(validation);
 }
 
+static int get_backup_file_changed(const char *root,
+		const alpm_backup_t *backup)
+{
+	char path[PATH_MAX];
+	int ret = 0;
+
+	snprintf(path, PATH_MAX, "%s%s", root, backup->name);
+
+	/* if we find the file, calculate checksums, otherwise it is missing */
+	if(access(path, R_OK) == 0) {
+		char *md5sum = alpm_compute_md5sum(path);
+
+		if(md5sum == NULL) {
+			pm_printf(ALPM_LOG_ERROR,
+					_("could not calculate checksums for %s\n"), path);
+			return 0;
+		}
+
+		/* if checksums don't match, file has been modified */
+		ret = strcmp(md5sum, backup->hash) != 0;
+		free(md5sum);
+	} else if(errno != ENOENT) {
+			pm_printf(ALPM_LOG_ERROR,
+					_("could not read %s: %s\n"), path, strerror(errno));
+	}
+	return ret;
+}
+
 static const char *get_backup_file_status(const char *root,
 		const alpm_backup_t *backup)
 {
@@ -401,7 +429,7 @@ static const char *get_backup_file_status(const char *root,
 
 /* Display list of backup files and their modification states
  */
-void dump_pkg_backups(alpm_pkg_t *pkg)
+void dump_backup_status(alpm_pkg_t *pkg)
 {
 	alpm_list_t *i;
 	const char *root = alpm_option_get_root(config->handle);
@@ -450,6 +478,32 @@ void dump_pkg_files(alpm_pkg_t *pkg, int quiet)
 	fflush(stdout);
 }
 
+void dump_pkg_backups(alpm_pkg_t *pkg, int quiet, int all)
+{
+	const char *pkgname, *root;
+	alpm_list_t *backups;
+	alpm_list_t *i;
+
+	pkgname = alpm_pkg_get_name(pkg);
+	backups = alpm_pkg_get_backup(pkg);
+	root = alpm_option_get_root(config->handle);
+
+	for(i = backups; i; i = i->next) {
+		alpm_backup_t *backup = i->data;
+
+		if(!all && backup->hash && !get_backup_file_changed(root, backup)) {
+			continue;
+		}
+
+		if(!quiet) {
+			printf("%s%s%s ", config->colstr.title, pkgname, config->colstr.nocolor);
+		}
+		printf("%s%s\n", root, backup->name);
+	}
+
+	fflush(stdout);
+}
+
 /* Display the changelog of a package
  */
 void dump_pkg_changelog(alpm_pkg_t *pkg)

src/pacman/package.h

@@ -24,7 +24,8 @@
 
 void dump_pkg_full(alpm_pkg_t *pkg, int extra);
 
-void dump_pkg_backups(alpm_pkg_t *pkg);
+void dump_backup_status(alpm_pkg_t *pkg);
+void dump_pkg_backups(alpm_pkg_t *pkg, int quiet, int all);
 void dump_pkg_files(alpm_pkg_t *pkg, int quiet);
 void dump_pkg_changelog(alpm_pkg_t *pkg);
 

src/pacman/pacman.c

@@ -150,6 +150,7 @@ static void usage(int op, const char * const myname)
 			addlist(_("  -t, --unrequired     list packages not (optionally) required by any\n"
 			          "                       package (-tt to ignore optdepends) [filter]\n"));
 			addlist(_("  -u, --upgrades       list outdated packages [filter]\n"));
+			addlist(_("  -w, --backup         list modified backup files of a package (-xx for all backup files)\n"));
 		} else if(op == PM_OP_SYNC) {
 			printf("%s:  %s {-S --sync} [%s] [%s]\n", str_usg, myname, str_opt, str_pkg);
 			printf("%s:\n", str_opt);
@@ -516,6 +517,10 @@ static int parsearg_query(int opt)
 		case 'c':
 			config->op_q_changelog = 1;
 			break;
+		case OP_BACKUP:
+		case 'w':
+			(config->op_q_backup)++;
+			break;
 		case OP_DEPS:
 		case 'd':
 			config->op_q_deps = 1;
@@ -583,6 +588,7 @@ static void checkargs_query_display_opts(const char *opname) {
 	invalid_opt(config->op_q_check, opname, "--check");
 	invalid_opt(config->op_q_info, opname, "--info");
 	invalid_opt(config->op_q_list, opname, "--list");
+	invalid_opt(config->op_q_backup, opname, "--backup");
 }
 
 static void checkargs_query_filter_opts(const char *opname) {
@@ -896,6 +902,7 @@ static int parseargs(int argc, char *argv[])
 		{"dbpath",     required_argument, 0, OP_DBPATH},
 		{"cascade",    no_argument,       0, OP_CASCADE},
 		{"changelog",  no_argument,       0, OP_CHANGELOG},
+		{"backup",     no_argument,       0, OP_BACKUP},
 		{"clean",      no_argument,       0, OP_CLEAN},
 		{"nodeps",     no_argument,       0, OP_NODEPS},
 		{"deps",       no_argument,       0, OP_DEPS},

src/pacman/query.c

@@ -315,6 +315,9 @@ static int display(alpm_pkg_t *pkg)
 	if(config->op_q_list) {
 		dump_pkg_files(pkg, config->quiet);
 	}
+	if(config->op_q_backup) {
+		dump_pkg_backups(pkg, config->quiet, config->op_q_backup != 1);
+	}
 	if(config->op_q_changelog) {
 		dump_pkg_changelog(pkg);
 	}
@@ -325,8 +328,8 @@ static int display(alpm_pkg_t *pkg)
 			ret = check_pkg_full(pkg);
 		}
 	}
-	if(!config->op_q_info && !config->op_q_list
-			&& !config->op_q_changelog && !config->op_q_check) {
+	if(!config->op_q_info && !config->op_q_list && !config->op_q_changelog
+			&& !config->op_q_check && !config->op_q_backup) {
 		if(!config->quiet) {
 			const colstr_t *colstr = &config->colstr;
 			printf("%s%s %s%s%s", colstr->title, alpm_pkg_get_name(pkg),
@@ -431,7 +434,7 @@ int pacman_query(alpm_list_t *targets)
 	db_local = alpm_get_localdb(config->handle);
 
 	/* operations on all packages in the local DB
-	 * valid: no-op (plain -Q), list, info, check
+	 * valid: no-op (plain -Q), list, info, check, backup
 	 * invalid: isfile, owns */
 	if(targets == NULL) {
 		if(config->op_q_isfile || config->op_q_owns) {