bfstd: Add a thread-safe wrapper for strerror()

8 files changed, 63 insertions, 7 deletions

diff --git a/src/bfstd.c b/src/bfstd.c
index fcf4a6d..e9214d4 100644
--- a/src/bfstd.c
+++ b/src/bfstd.c
@@ -12,6 +12,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <langinfo.h>
+#include <locale.h>
 #include <nl_types.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -276,6 +277,48 @@ char *xstpencpy(char *dest, char *end, const char *src, size_t n) {
 	}
 }
 
+const char *xstrerror(int errnum) {
+	int saved = errno;
+	const char *ret = NULL;
+	static thread_local char buf[256];
+
+#if __APPLE__
+	// No strerror_l() on macOS
+	if (strerror_r(errnum, buf, sizeof(buf)) == 0) {
+		ret = buf;
+	}
+#else
+#  if __NetBSD__
+	// NetBSD has no thread-specific locales
+	locale_t loc = LC_GLOBAL_LOCALE;
+#  else
+	locale_t loc = uselocale((locale_t)0);
+#  endif
+
+	locale_t copy = loc;
+	if (copy == LC_GLOBAL_LOCALE) {
+		copy = duplocale(copy);
+	}
+
+	if (copy != (locale_t)0) {
+		ret = strerror_l(errnum, loc);
+	}
+
+	if (loc == LC_GLOBAL_LOCALE) {
+		freelocale(copy);
+	}
+#endif
+
+	if (!ret) {
+		// Fallback for strerror_[lr]() or duplocale() failures
+		snprintf(buf, sizeof(buf), "Unknown error %d", errnum);
+		ret = buf;
+	}
+
+	errno = saved;
+	return ret;
+}
+
 void xstrmode(mode_t mode, char str[11]) {
 	strcpy(str, "----------");
 
diff --git a/src/bfstd.h b/src/bfstd.h
index fb77399..abde24e 100644
--- a/src/bfstd.h
+++ b/src/bfstd.h
@@ -167,6 +167,17 @@ char *xstpecpy(char *dest, char *end, const char *src);
 char *xstpencpy(char *dest, char *end, const char *src, size_t n);
 
 /**
+ * Thread-safe strerror().
+ *
+ * @param errnum
+ *         An error number.
+ * @return
+ *         A string describing that error, which remains valid until the next
+ *         xstrerror() call in the same thread.
+ */
+const char *xstrerror(int errnum);
+
+/**
  * Format a mode like ls -l (e.g. -rw-r--r--).
  *
  * @param mode
diff --git a/src/color.c b/src/color.c
index 788d35d..fbb5edf 100644
--- a/src/color.c
+++ b/src/color.c
@@ -1239,7 +1239,7 @@ static int cvbuff(CFILE *cfile, const char *format, va_list args) {
 				break;
 
 			case 'm':
-				if (dstrcat(&cfile->buffer, strerror(error)) != 0) {
+				if (dstrcat(&cfile->buffer, xstrerror(error)) != 0) {
 					return -1;
 				}
 				break;
diff --git a/src/eval.c b/src/eval.c
index 9f4896a..e0dd97b 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1376,7 +1376,7 @@ static enum bftw_action eval_callback(const struct BFTW *ftwbuf, void *ptr) {
 
 	if (ftwbuf->type == BFS_ERROR) {
 		if (!eval_should_ignore(&state, ftwbuf->error)) {
-			eval_error(&state, "%s.\n", strerror(ftwbuf->error));
+			eval_error(&state, "%s.\n", xstrerror(ftwbuf->error));
 		}
 		state.action = BFTW_PRUNE;
 		goto done;
diff --git a/src/parse.c b/src/parse.c
index 7766a7b..976f7cb 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -1127,7 +1127,7 @@ static struct bfs_expr *parse_color(struct parser_state *state, int color, int a
 
 	if (color) {
 		if (!colors) {
-			parse_expr_error(state, expr, "Error parsing $$LS_COLORS: %s.\n", strerror(ctx->colors_error));
+			parse_expr_error(state, expr, "Error parsing $$LS_COLORS: %s.\n", xstrerror(ctx->colors_error));
 			bfs_expr_free(expr);
 			return NULL;
 		}
@@ -3741,7 +3741,7 @@ struct bfs_ctx *bfs_parse_cmdline(int argc, char *argv[]) {
 	}
 
 	if (state.use_color == COLOR_AUTO && !ctx->colors) {
-		bfs_warning(ctx, "Error parsing $$LS_COLORS: %s.\n\n", strerror(ctx->colors_error));
+		bfs_warning(ctx, "Error parsing $$LS_COLORS: %s.\n\n", xstrerror(ctx->colors_error));
 	}
 
 	if (bfs_optimize(ctx) != 0) {
diff --git a/src/printf.c b/src/printf.c
index 98bcb0f..704e26d 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -744,7 +744,7 @@ int bfs_printf_parse(const struct bfs_ctx *ctx, struct bfs_expr *expr, const cha
 				if (!directive.ptr) {
 					int error = errno;
 					bfs_expr_error(ctx, expr);
-					bfs_error(ctx, "Couldn't parse the mount table: %s.\n", strerror(error));
+					bfs_error(ctx, "Couldn't parse the mount table: %s.\n", xstrerror(error));
 					goto directive_error;
 				}
 				break;
diff --git a/src/thread.h b/src/thread.h
index ab95a79..a59033c 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -8,6 +8,7 @@
 #ifndef BFS_THREAD_H
 #define BFS_THREAD_H
 
+#include "bfstd.h"
 #include "config.h"
 #include "diag.h"
 #include <errno.h>
@@ -23,7 +24,7 @@
 #endif
 
 #define thread_verify(expr, cond) \
-	bfs_verify((errno = (expr), (cond)), "%s: %s", #expr, strerror(errno))
+	bfs_verify((errno = (expr), (cond)), "%s: %s", #expr, xstrerror(errno))
 
 /**
  * Wrapper for pthread_create().
diff --git a/src/xregex.c b/src/xregex.c
index 87b692e..3df27f0 100644
--- a/src/xregex.c
+++ b/src/xregex.c
@@ -3,6 +3,7 @@
 
 #include "xregex.h"
 #include "alloc.h"
+#include "bfstd.h"
 #include "config.h"
 #include "diag.h"
 #include "sanity.h"
@@ -274,7 +275,7 @@ void bfs_regfree(struct bfs_regex *regex) {
 
 char *bfs_regerror(const struct bfs_regex *regex) {
 	if (!regex) {
-		return strdup(strerror(ENOMEM));
+		return strdup(xstrerror(ENOMEM));
 	}
 
 #if BFS_USE_ONIGURUMA