[src/trunk]: src/sys/lib/libsa To avoid backwards seeks on sequential devices...

[scw <scw%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/901394748eef
branches:  trunk
changeset: 517266:901394748eef
user:      scw <scw%NetBSD.org@localhost>
date:      Fri Nov 09 18:31:08 2001 +0000

description:
To avoid backwards seeks on sequential devices (eq. QIC tapes), read all
the program headers in one operation into an internal buffer.

diffstat:

 sys/lib/libsa/loadfile_elf32.c |  68 +++++++++++++++++++++++------------------
 1 files changed, 38 insertions(+), 30 deletions(-)

diffs (123 lines):

diff -r 65ea4df49365 -r 901394748eef sys/lib/libsa/loadfile_elf32.c
--- a/sys/lib/libsa/loadfile_elf32.c    Fri Nov 09 18:27:59 2001 +0000
+++ b/sys/lib/libsa/loadfile_elf32.c    Fri Nov 09 18:31:08 2001 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: loadfile_elf32.c,v 1.4 2001/10/31 21:24:09 thorpej Exp $ */
+/* $NetBSD: loadfile_elf32.c,v 1.5 2001/11/09 18:31:08 scw Exp $ */
 
 /*-
  * Copyright (c) 1997 The NetBSD Foundation, Inc.
@@ -308,6 +308,7 @@
        int flags;
 {
        Elf_Shdr *shp;
+       Elf_Phdr *phdr;
        int i, j;
        size_t sz;
        int first;
@@ -316,20 +317,24 @@
 
        internalize_ehdr(elf->e_ident[EI_DATA], elf);
 
+       sz = elf->e_phnum * sizeof(Elf_Phdr);
+       phdr = ALLOC(sz);
+
+       if (lseek(fd, elf->e_phoff, SEEK_SET) == -1)  {
+               WARN(("lseek phdr"));
+               FREE(phdr, sz);
+               return 1;
+       }
+       if (read(fd, phdr, sz) != sz) {
+               WARN(("read program headers"));
+               FREE(phdr, sz);
+               return 1;
+       }
+
        for (first = 1, i = 0; i < elf->e_phnum; i++) {
-               Elf_Phdr phdr;
-               if (lseek(fd, elf->e_phoff + sizeof(phdr) * i, SEEK_SET)
-                   == -1)  {
-                       WARN(("lseek phdr"));
-                       return 1;
-               }
-               if (read(fd, (void *)&phdr, sizeof(phdr)) != sizeof(phdr)) {
-                       WARN(("read phdr"));
-                       return 1;
-               }
-               internalize_phdr(elf->e_ident[EI_DATA], &phdr);
-               if (phdr.p_type != PT_LOAD ||
-                   (phdr.p_flags & (PF_W|PF_X)) == 0)
+               internalize_phdr(elf->e_ident[EI_DATA], &phdr[i]);
+               if (phdr[i].p_type != PT_LOAD ||
+                   (phdr[i].p_flags & (PF_W|PF_X)) == 0)
                        continue;
 
 #define IS_TEXT(p)     (p.p_flags & PF_X)
@@ -338,48 +343,51 @@
                /*
                 * XXX: Assume first address is lowest
                 */
-               if ((IS_TEXT(phdr) && (flags & LOAD_TEXT)) ||
-                   (IS_DATA(phdr) && (flags & LOAD_DATA))) {
+               if ((IS_TEXT(phdr[i]) && (flags & LOAD_TEXT)) ||
+                   (IS_DATA(phdr[i]) && (flags & LOAD_DATA))) {
 
                        /* Read in segment. */
                        PROGRESS(("%s%lu", first ? "" : "+",
-                           (u_long)phdr.p_filesz));
+                           (u_long)phdr[i].p_filesz));
 
-                       if (lseek(fd, phdr.p_offset, SEEK_SET) == -1)  {
+                       if (lseek(fd, phdr[i].p_offset, SEEK_SET) == -1)  {
                                WARN(("lseek text"));
+                               FREE(phdr, sz);
                                return 1;
                        }
-                       if (READ(fd, phdr.p_vaddr, phdr.p_filesz) !=
-                           phdr.p_filesz) {
+                       if (READ(fd, phdr[i].p_vaddr, phdr[i].p_filesz) !=
+                           phdr[i].p_filesz) {
                                WARN(("read text"));
+                               FREE(phdr, sz);
                                return 1;
                        }
                        first = 0;
 
                }
-               if ((IS_TEXT(phdr) && (flags & (LOAD_TEXT|COUNT_TEXT))) ||
-                   (IS_DATA(phdr) && (flags & (LOAD_DATA|COUNT_TEXT)))) {
-                       pos = phdr.p_vaddr;
+               if ((IS_TEXT(phdr[i]) && (flags & (LOAD_TEXT|COUNT_TEXT))) ||
+                   (IS_DATA(phdr[i]) && (flags & (LOAD_DATA|COUNT_TEXT)))) {
+                       pos = phdr[i].p_vaddr;
                        if (minp > pos)
                                minp = pos;
-                       pos += phdr.p_filesz;
+                       pos += phdr[i].p_filesz;
                        if (maxp < pos)
                                maxp = pos;
                }
 
                /* Zero out bss. */
-               if (IS_BSS(phdr) && (flags & LOAD_BSS)) {
+               if (IS_BSS(phdr[i]) && (flags & LOAD_BSS)) {
                        PROGRESS(("+%lu",
-                           (u_long)(phdr.p_memsz - phdr.p_filesz)));
-                       BZERO((phdr.p_vaddr + phdr.p_filesz),
-                           phdr.p_memsz - phdr.p_filesz);
+                           (u_long)(phdr[i].p_memsz - phdr[i].p_filesz)));
+                       BZERO((phdr[i].p_vaddr + phdr[i].p_filesz),
+                           phdr[i].p_memsz - phdr[i].p_filesz);
                }
-               if (IS_BSS(phdr) && (flags & (LOAD_BSS|COUNT_BSS))) {
-                       pos += phdr.p_memsz - phdr.p_filesz;
+               if (IS_BSS(phdr[i]) && (flags & (LOAD_BSS|COUNT_BSS))) {
+                       pos += phdr[i].p_memsz - phdr[i].p_filesz;
                        if (maxp < pos)
                                maxp = pos;
                }
        }
+       FREE(phdr, sz);
 
        /*
         * Copy the ELF and section headers.