kernel: use 64-bit virtual entry point for expanded header, document behaviour in...

[plan9front.git] / sys / src / 9 / port / sysproc.c

diff --git a/sys/src/9/port/sysproc.c b/sys/src/9/port/sysproc.c
index a6466e40b494905f42d80409384160151cbda41a..6e0af5332492b762d6e671dfc511427ce00fbe7e 100644 (file)
--- a/sys/src/9/port/sysproc.c
+++ b/sys/src/9/port/sysproc.c
@@ -234,6 +234,8 @@ shargs(char *s, int n, char **ap)
 {
        int i;
 
+       if(n <= 2 || s[0] != '#' || s[1] != '!')
+               return -1;
        s += 2;
        n -= 2;         /* skip #! */
        for(i=0;; i++){
@@ -261,27 +263,42 @@ shargs(char *s, int n, char **ap)
        return i;
 }
 
-static ulong
-l2be(long l)
+ulong
+beswal(ulong l)
 {
-       uchar *cp;
+       uchar *p;
 
-       cp = (uchar*)&l;
-       return (cp[0]<<24) | (cp[1]<<16) | (cp[2]<<8) | cp[3];
+       p = (uchar*)&l;
+       return (p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
+}
+
+uvlong
+beswav(uvlong v)
+{
+       uchar *p;
+
+       p = (uchar*)&v;
+       return ((uvlong)p[0]<<56) | ((uvlong)p[1]<<48) | ((uvlong)p[2]<<40)
+                                 | ((uvlong)p[3]<<32) | ((uvlong)p[4]<<24)
+                                 | ((uvlong)p[5]<<16) | ((uvlong)p[6]<<8)
+                                 | (uvlong)p[7];
 }
 
 uintptr
 sysexec(va_list list)
 {
-       Exec exec;
-       char line[sizeof(Exec)];
+       struct {
+               Exec;
+               uvlong  hdr[1];
+       } ehdr;
+       char line[sizeof(ehdr)];
        char *progarg[sizeof(line)/2+1];
        volatile char *args, *elem, *file0;
        char **argv, **argp, **argp0;
        char *a, *e, *charp, *file;
        int i, n, indir;
        ulong magic, ssize, nargs, nbytes;
-       uintptr t, d, b, entry, bssend, text, data, bss, tstk, align;
+       uintptr t, d, b, entry, text, data, bss, bssend, tstk, align;
        Segment *s, *ts;
        Image *img;
        Tos *tos;
@@ -311,7 +328,7 @@ sysexec(va_list list)
                }
                nexterror();
        }
-       align = BY2PG;
+       align = BY2PG-1;
        indir = 0;
        file = file0;
        for(;;){
@@ -323,39 +340,47 @@ sysexec(va_list list)
                if(!indir)
                        kstrdup(&elem, up->genbuf);
 
-               n = devtab[tc->type]->read(tc, &exec, sizeof(Exec), 0);
-               if(n <= 2)
-                       error(Ebadexec);
-               magic = l2be(exec.magic);
-               if(n == sizeof(Exec) && (magic == AOUT_MAGIC)){
-                       entry = l2be(exec.entry);
-                       text = l2be(exec.text);
-                       if(magic & HDR_MAGIC)
-                               text += 8;
-                       switch(magic){
-                       case S_MAGIC:   /* 2MB segment alignment for amd64 */
-                               align = 0x200000;
-                               break;
-                       case V_MAGIC:   /* 16K segment alignment for mips */
-                               align = 0x4000;
-                               break;
-                       case R_MAGIC:   /* 64K segment alignment for arm64 */
-                               align = 0x10000;
-                               break;
+               n = devtab[tc->type]->read(tc, &ehdr, sizeof(ehdr), 0);
+               if(n >= sizeof(Exec)) {
+                       magic = beswal(ehdr.magic);
+                       if(magic == AOUT_MAGIC) {
+                               if(magic & HDR_MAGIC) {
+                                       if(n < sizeof(ehdr))
+                                               error(Ebadexec);
+                                       entry = beswav(ehdr.hdr[0]);
+                                       text = UTZERO+sizeof(ehdr);
+                               } else {
+                                       entry = beswal(ehdr.entry);
+                                       text = UTZERO+sizeof(Exec);
+                               }
+                               if(entry < text)
+                                       error(Ebadexec);
+                               text += beswal(ehdr.text);
+                               if(text <= entry || text >= (USTKTOP-USTKSIZE))
+                                       error(Ebadexec);
+
+                               switch(magic){
+                               case S_MAGIC:   /* 2MB segment alignment for amd64 */
+                                       align = 0x1fffff;
+                                       break;
+                               case V_MAGIC:   /* 16K segment alignment for mips */
+                                       align = 0x3fff;
+                                       break;
+                               case R_MAGIC:   /* 64K segment alignment for arm64 */
+                                       align = 0xffff;
+                                       break;
+                               }
+                               break; /* for binary */
                        }
-                       if(text >= (USTKTOP-USTKSIZE)-(UTZERO+sizeof(Exec))
-                       || entry < UTZERO+sizeof(Exec)
-                       || entry >= UTZERO+sizeof(Exec)+text)
-                               error(Ebadexec);
-                       break; /* for binary */
                }
 
+               if(indir++)
+                       error(Ebadexec);
+
                /*
                 * Process #! /bin/sh args ...
                 */
-               memmove(line, &exec, n);
-               if(line[0]!='#' || line[1]!='!' || indir++)
-                       error(Ebadexec);
+               memmove(line, &ehdr, n);
                n = shargs(line, n, progarg);
                if(n < 1)
                        error(Ebadexec);
@@ -371,10 +396,10 @@ sysexec(va_list list)
                cclose(tc);
        }
 
-       data = l2be(exec.data);
-       bss = l2be(exec.bss);
-       align--;
-       t = (UTZERO+sizeof(Exec)+text+align) & ~align;
+       t = (text+align) & ~align;
+       text -= UTZERO;
+       data = beswal(ehdr.data);
+       bss = beswal(ehdr.bss);
        align = BY2PG-1;
        d = (t + data + align) & ~align;
        bssend = t + data + bss;
@@ -518,7 +543,7 @@ sysexec(va_list list)
        up->seg[TSEG] = ts;
        ts->flushme = 1;
        ts->fstart = 0;
-       ts->flen = sizeof(Exec)+text;
+       ts->flen = text;
        unlock(img);
 
        /* Data. Shared. */