6 files changed, 54 insertions, 10 deletions
diff --git a/src/shared/include/camellia/errno.h b/src/shared/include/camellia/errno.h
index 1e4841c..263bd25 100644
--- a/src/shared/include/camellia/errno.h
+++ b/src/shared/include/camellia/errno.h
@@ -1,15 +1,18 @@
 #pragma once
+/* the comments are directly pasted into user visible strings.
+ * keep them short, don't include " */
 
+#define EGENERIC 1 /* unknown error */
 #define EFAULT 2
-#define EBADF 3 /* Invalid file descriptor. */
+#define EBADF 3 /* bad file descriptor */
 #define EINVAL 4
-#define ENOSYS 5 /* Unsupported. */
+#define ENOSYS 5 /* unsupported */
 #define ERANGE 6
 #define ENOMEM 7
 #define ENOENT 8
 #define ENOTEMPTY 9
 #define EACCES 10
-#define EMFILE 11 /* All file descriptors taken. */
+#define EMFILE 11 /* all file descriptors taken */
 #define ECONNRESET 12
 
 #define EISDIR 200
diff --git a/src/user/lib/include/__errno.h b/src/user/lib/include/__errno.h
new file mode 100644
index 0000000..d6d5e6a
--- /dev/null
+++ b/src/user/lib/include/__errno.h
@@ -0,0 +1,16 @@
+/* generated by awk */
+#ifdef E
+E(  1, "EGENERIC unknown error")
+E(  2, "EFAULT")
+E(  3, "EBADF bad file descriptor")
+E(  4, "EINVAL")
+E(  5, "ENOSYS unsupported")
+E(  6, "ERANGE")
+E(  7, "ENOMEM")
+E(  8, "ENOENT")
+E(  9, "ENOTEMPTY")
+E( 10, "EACCES")
+E( 11, "EMFILE all file descriptors taken")
+E( 12, "ECONNRESET")
+E(200, "EISDIR")
+#endif
diff --git a/src/user/lib/include/__errno.h.awk b/src/user/lib/include/__errno.h.awk
new file mode 100644
index 0000000..6232835
--- /dev/null
+++ b/src/user/lib/include/__errno.h.awk
@@ -0,0 +1,20 @@
+BEGIN {
+	print "/* generated by awk */";
+	print "#ifdef E";
+}
+
+END {
+	print "#endif";
+}
+
+/#define/ {
+	comment = $2;
+	num = $3;
+	# extract the comment, if present
+	if (index($0, "/*")) {
+		sub(/[^/]*\/\*/, "");
+		sub(/ *\*\//, "");
+		comment = comment $0;
+	}
+	printf "E(%3s, \"%s\")\n", num, comment;
+}
diff --git a/src/user/lib/stdio/misc.c b/src/user/lib/stdio/misc.c
index a140ee4..45144f3 100644
--- a/src/user/lib/stdio/misc.c
+++ b/src/user/lib/stdio/misc.c
@@ -5,7 +5,7 @@
 
 void perror(const char *s) {
 	if (s) fprintf(stderr, "%s: ", s);
-	fprintf(stderr, "errno %d\n", errno);
+	fprintf(stderr, "%s\n", strerror(errno));
 }
 
 int puts(const char *s) {
diff --git a/src/user/lib/string/strerror.c b/src/user/lib/string/strerror.c
new file mode 100644
index 0000000..1f5fc29
--- /dev/null
+++ b/src/user/lib/string/strerror.c
@@ -0,0 +1,11 @@
+#include <string.h>
+
+static const char *errstr[] = {
+#	define E(n, str) [n] = str,
+#	include <__errno.h>
+#	undef E
+};
+
+char *strerror(int n) {
+	return (char*)(errstr[n] ? errstr[n] : "unknown error");
+}
diff --git a/src/user/lib/string.c b/src/user/lib/string/string.c
index fa9c0ca..f141a3d 100644
--- a/src/user/lib/string.c
+++ b/src/user/lib/string/string.c
@@ -151,12 +151,6 @@ char *strdup(const char *s) {
 	return buf;
 }
 
-// TODO strerror mapping
-char *strerror(int errnum) {
-	(void)errnum;
-	return "unknown error";
-}
-
 /* strings.h */
 int strcasecmp(const char *s1, const char *s2) {
 	return strncasecmp(s1, s2, ~0);