pacman: use dynamic string allocation where it makes sense

None of these are hot-code paths, and at least the target reading has
little need for an arbitrary length limitation (however crazy it might
be to have longer arguments).

Signed-off-by: Dan McGee <dan@archlinux.org>

src/pacman/pacman.c

@@ -821,13 +821,13 @@ int main(int argc, char *argv[])
 
 	/* we support reading targets from stdin if a cmdline parameter is '-' */
 	if(!isatty(fileno(stdin)) && alpm_list_find_str(pm_targets, "-")) {
-		char line[PATH_MAX];
-		int i = 0;
+		size_t current_size = PATH_MAX, i = 0;
+		char *line = malloc(current_size);
 
 		/* remove the '-' from the list */
 		pm_targets = alpm_list_remove_str(pm_targets, "-", NULL);
 
-		while(i < PATH_MAX && (line[i] = (char)fgetc(stdin)) != EOF) {
+		while((line[i] = (char)fgetc(stdin)) != EOF) {
 			if(isspace((unsigned char)line[i])) {
 				/* avoid adding zero length arg when multiple spaces separate args */
 				if(i > 0) {
@@ -837,11 +837,23 @@ int main(int argc, char *argv[])
 				}
 			} else {
 				i++;
+				/* we may be at the end of our allocated buffer now */
+				if(i >= current_size) {
+					char *new = realloc(line, current_size * 2);
+					if(new) {
+						line = new;
+						current_size *= 2;
+					} else {
+						free(line);
+						line = NULL;
+						break;
+					}
+				}
 			}
 		}
-		/* check for buffer overflow */
-		if(i >= PATH_MAX) {
-			pm_printf(ALPM_LOG_ERROR, _("buffer overflow detected in arg parsing\n"));
+		/* check for memory exhaustion */
+		if(!line) {
+			pm_printf(ALPM_LOG_ERROR, _("memory exhausted in argument parsing\n"));
 			cleanup(EXIT_FAILURE);
 		}
 
@@ -850,6 +862,7 @@ int main(int argc, char *argv[])
 			line[i] = '\0';
 			pm_targets = alpm_list_add(pm_targets, strdup(line));
 		}
+		free(line);
 		if(!freopen(ctermid(NULL), "r", stdin)) {
 			pm_printf(ALPM_LOG_ERROR, _("failed to reopen stdin for reading: (%s)\n"),
 					strerror(errno));

src/pacman/sync.c

@@ -122,7 +122,7 @@ static int sync_cleandb(const char *dbpath, int keep_used)
 static int sync_cleandb_all(void)
 {
 	const char *dbpath;
-	char newdbpath[PATH_MAX];
+	char *newdbpath;
 	int ret = 0;
 
 	dbpath = alpm_option_get_dbpath(config->handle);
@@ -135,8 +135,12 @@ static int sync_cleandb_all(void)
 	 * only the unused sync dbs in dbpath/sync/ */
 	ret += sync_cleandb(dbpath, 0);
 
-	sprintf(newdbpath, "%s%s", dbpath, "sync/");
+	if(asprintf(&newdbpath, "%s%s", dbpath, "sync/") < 0) {
+		ret += 1;
+		return ret;
+	}
 	ret += sync_cleandb(newdbpath, 1);
+	free(newdbpath);
 
 	printf(_("Database directory cleaned up\n"));
 	return ret;

src/pacman/util.c

@@ -680,8 +680,9 @@ void signature_display(const char *title, alpm_siglist_t *siglist)
 	} else {
 		size_t i;
 		for(i = 0; i < siglist->count; i++) {
-			char sigline[PATH_MAX];
+			char *sigline;
 			const char *status, *validity, *name;
+			int ret;
 			alpm_sigresult_t *result = siglist->results + i;
 			/* Don't re-indent the first result */
 			if(i != 0) {
@@ -726,10 +727,15 @@ void signature_display(const char *title, alpm_siglist_t *siglist)
 					break;
 			}
 			name = result->key.uid ? result->key.uid : result->key.fingerprint;
-			snprintf(sigline, PATH_MAX, _("%s, %s from \"%s\""),
+			ret = pm_asprintf(&sigline, _("%s, %s from \"%s\""),
 					status, validity, name);
+			if(ret < 1) {
+				pm_fprintf(stderr, ALPM_LOG_ERROR,  _("failed to allocate string\n"));
+				continue;
+			}
 			indentprint(sigline, len);
 			printf("\n");
+			free(sigline);
 		}
 	}
 }