Chore: cleaned up the exit code to cleanly interface with libc

We use weak linking to ensure we clean up at exit time correctly. If
libc is linked, then we call our cleanup function by registering an
atexit callback with the library. If libc is not linked, we have a weak
symbol that results in a noop. Similarly, if we call rt·exit while
linked with libc, this immediately calls libc's exit (which will call
our cleanup as we registered it). If we are not linked to libc, exit()
is given as a weak link to a noop function.

6 files changed, 21 insertions, 18 deletions

diff --git a/include/base.h b/include/base.h
index a7e9319..d532a85 100644
--- a/include/base.h
+++ b/include/base.h
@@ -3,8 +3,8 @@
 // ------------------------------------------------------------------------
 // standard library
 
+#include <rt.h>
 #include <sys.h>
-#include <arch/types.h>
 
 // TODO: remove dependency system headers
 #include <assert.h>
diff --git a/include/base/gz.h b/include/base/gz.h
index 3b3a830..ac241d3 100644
--- a/include/base/gz.h
+++ b/include/base/gz.h
@@ -25,5 +25,5 @@ int        gz·putbyte(gz·Stream *s, byte str);
 int        gz·putstring(gz·Stream *s, byte *str);
 int        gz·printf(gz·Stream *s, byte *fmt, ...);
 int        gz·flush(gz·Stream *s);
-int        gz·seek(gz·Stream *s, long off, enum SeekPos whence);
+int        gz·seek(gz·Stream *s, long off, int whence);
 long       gz·tell(gz·Stream *s);
diff --git a/include/base/io.h b/include/base/io.h
index 5e0f1e0..5d31282 100644
--- a/include/base/io.h
+++ b/include/base/io.h
@@ -1,12 +1,5 @@
 #pragma once
 
-enum SeekPos
-{
-    seek·cur = SEEK_CUR,
-    seek·set = SEEK_SET,
-    seek·end = SEEK_END
-};
-
 typedef struct io·Reader
 {
     int (*read)(void*, int sz, int n, void *buf);
@@ -22,7 +15,7 @@ extern io·Peeker sys·Peeker;
 
 typedef struct io·Seeker
 {
-    int        (*seek)(void *skr, long off, enum SeekPos whence);
+    int        (*seek)(void *skr, long off, int whence);
     long       (*tell)(void *skr);
 } io·Seeker;
 extern io·Seeker sys·Seeker;
@@ -93,10 +86,11 @@ int        io·putbyte(io·Stream *s, byte c);
 int        io·putstring(io·Stream *s, string str);
 int        io·write(io·Stream *s, int sz, int n, void *buf);
 int        io·flush(io·Stream *s);
-int        io·seek(io·Stream *s, long off, enum SeekPos whence);
+int        io·seek(io·Stream *s, long off, int whence);
 long       io·tell(io·Stream *s);
 
 /* buffered i/o */
+typedef struct io·Header io·Header;
 typedef struct io·Buffer io·Buffer;
 
 #define iota(x) (1 << (x))
@@ -116,21 +110,26 @@ enum
 };
 #undef iota
 
-struct io·Buffer
+struct io·Header
 {
-    int state, id, flag;
+    int state, fd, flag;
     struct{
-        int in;      /* negative number of bytes at end */
-        int out;     /* number of bytes at start */
-        int line;    /* number of bytes after last readline */
+        int in;    /* negative number of bytes at end */
+        int out;   /* number of bytes at start */
+        int ln;    /* number of bytes after last readline */
     } off;
     intptr pos, cap; /* position in file, capacity of buffer */
     uchar *b,*g,*e;  /* start, good bytes, end of byte pointers */
-    uchar bytes[];
+};
+
+struct io·Buffer
+{
+    io·Header;
+    uchar bytes[io·BufLen+io·BufUngets];
 };
 
 int     bio·init(io·Buffer *io, int fd, int mode);
-int     bio·initcap(io·Buffer *io, int fd, int mode, int cap);
+int     bio·initcap(io·Header *io, int fd, int mode, int cap, uchar *buf);
 
 /* basic os helpers */
 /* XXX: find a better location for this */
diff --git a/include/rt.h b/include/rt.h
index 43357cd..ce92af0 100644
--- a/include/rt.h
+++ b/include/rt.h
@@ -12,4 +12,5 @@ extern struct rt·Context
 
 extern char **rt·environ;
 
+int  rt·atexit(void (*func)(void *), void *arg);
 void noreturn rt·exit(int code);
diff --git a/include/sys.h b/include/sys.h
index 0c703a8..e983f2a 100644
--- a/include/sys.h
+++ b/include/sys.h
@@ -2,6 +2,7 @@
 
 /* types declarations */
 #include <arch/types.h>
+#include <arch/constants.h>
 
 #include <os/types.h>
 #include <os/constants.h>
@@ -14,6 +15,7 @@
 #define sys·ORead    0x0u
 #define sys·OWrite   0x1u
 #define sys·ORdwr    0x2u
+#define sys·OExec    sys·OPath
 
 /* seek */
 #define sys·SeekSet  0u
diff --git a/include/u.h b/include/u.h
index d415d82..fe251ac 100644
--- a/include/u.h
+++ b/include/u.h
@@ -112,6 +112,7 @@ typedef __builtin_va_list va_list;
 #define noreturn _Noreturn

 #define hidden __attribute__((__visibility__("hidden")))

 #define weakalias(old, new) extern __typeof(old) new __attribute__((weak, alias(#old)))

+#define weaklink __attribute__((weak))

 

 /* offsets */

 #define offsetof(t, d) __builtin_offsetof(t, d)