From 36b0897a42271e3248aa63da0b4b5c96326aeba8 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Sat, 23 Apr 2022 18:27:31 +0000
Subject: [PATCH] aux/aout2uimage: fix text section size rounding (for data
 section alignment)

the a.out header is not considered part of the image and
should not be loaded. it also has no contribution to the
rounding of the text section size.
---
 sys/src/cmd/aux/aout2uimage.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/sys/src/cmd/aux/aout2uimage.c b/sys/src/cmd/aux/aout2uimage.c
index e8a9e63b7..c557eadfa 100644
--- a/sys/src/cmd/aux/aout2uimage.c
+++ b/sys/src/cmd/aux/aout2uimage.c
@@ -100,9 +100,10 @@ main(int argc, char **argv)
 {
 	Fhdr fhdr;
 	u64int kzero;
+	ulong rtext;
 	uchar header[64];
 	char *ofile, *iname;
-	int n, arch;
+	int arch;
 
 	kzero = 0xF0000000;
 	ofile = nil;
@@ -116,7 +117,10 @@ main(int argc, char **argv)
 	infd = open(argv[0], OREAD);
 	if(infd < 0) sysfatal("infd: %r");
 	if(crackhdr(infd, &fhdr) == 0) sysfatal("crackhdr: %r");
-	
+	if((uint)mach->mtype >= nelem(archtab) || archtab[mach->mtype] == 0)
+		sysfatal("archloch");
+	arch = archtab[mach->mtype];
+	assert(sizeof(buf) >= mach->pgsize);
 	iname = strrchr(argv[0], '/');
 	if(iname != nil)
 		iname++;
@@ -127,29 +131,25 @@ main(int argc, char **argv)
 	if(outfd < 0) sysfatal("create: %r");
 	
 	tab = mkcrctab(0xEDB88320);
-	assert(sizeof(buf) >= mach->pgsize);
-	seek(infd, 0, 0);
+	seek(infd, fhdr.hdrsz, 0);	/* a.out header not part of the image */
 	seek(outfd, sizeof(header), 0);
 	dcrc = 0;
-	
-	copy(fhdr.hdrsz + fhdr.txtsz);
-	n = -(fhdr.hdrsz + fhdr.txtsz) & mach->pgsize - 1;
-	if(n > 0){
-		memset(buf, 0, n);
-		if(write(outfd, buf, n) < 0) sysfatal("write: %r");
-		dcrc = blockcrc(tab, dcrc, buf, n);
+	copy(fhdr.txtsz);
+
+	/* round text out to page boundary (see rebootcmd()) */
+	rtext = ((fhdr.entry + fhdr.txtsz + mach->pgsize-1) & -mach->pgsize) - fhdr.entry;
+	if(rtext > fhdr.txtsz){
+		memset(buf, 0, rtext - fhdr.txtsz);
+		if(write(outfd, buf, rtext - fhdr.txtsz) < 0) sysfatal("write: %r");
+		dcrc = blockcrc(tab, dcrc, buf, rtext - fhdr.txtsz);
 	}
 	copy(fhdr.datsz);
 	
-	if((uint)mach->mtype >= nelem(archtab) || archtab[mach->mtype] == 0)
-		sysfatal("archloch");
-	arch = archtab[mach->mtype];
-	
 	memset(header, 0, sizeof(header));
 	put(&header[0], 0x27051956); /* magic */
 	put(&header[8], time(0)); /* time */
-	put(&header[12], -(-(fhdr.hdrsz + fhdr.txtsz) & -mach->pgsize) + fhdr.datsz); /* image size */
-	put(&header[16], fhdr.txtaddr - fhdr.hdrsz - kzero); /* load address */
+	put(&header[12], rtext + fhdr.datsz); /* image size */
+	put(&header[16], fhdr.txtaddr - kzero); /* load address */
 	put(&header[20], fhdr.entry - kzero); /* entry point */
 	put(&header[24], dcrc); /* data crc */
 	header[28] = 23; /* os = plan 9 */