linux-user pull request 20210313

- fix elfload
 - fix executable page of /proc/self/maps
 - add preserve-arg[0] support for binfmt_misc
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Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-6.0-pull-request' into staging

linux-user pull request 20210313

- fix elfload
- fix executable page of /proc/self/maps
- add preserve-arg[0] support for binfmt_misc

# gpg: Signature made Sat 13 Mar 2021 09:47:23 GMT
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/linux-user-for-6.0-pull-request:
  linux-user/elfload: fix address calculation in fallback scenario
  linux-user/elfload: do not assume MAP_FIXED_NOREPLACE kernel support
  linux-user/elfload: munmap proper address in pgd_find_hole_fallback
  linux-user: manage binfmt-misc preserve-arg[0] flag
  linux-user: Fix executable page of /proc/self/maps

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

linux-user/elfload.c

@@ -2209,9 +2209,8 @@ static uintptr_t pgd_find_hole_fallback(uintptr_t guest_size, uintptr_t brk,
             void * mmap_start = mmap((void *) align_start, guest_size,
                                      PROT_NONE, flags, -1, 0);
             if (mmap_start != MAP_FAILED) {
-                munmap((void *) align_start, guest_size);
+                munmap(mmap_start, guest_size);
-                if (MAP_FIXED_NOREPLACE != 0 ||
+                if (mmap_start == (void *) align_start) {
-                    mmap_start == (void *) align_start) {
                     return (uintptr_t) mmap_start + offset;
                 }
             }
@@ -2236,7 +2235,8 @@ static uintptr_t pgb_find_hole(uintptr_t guest_loaddr, uintptr_t guest_size,
     brk = (uintptr_t)sbrk(0);
 
     if (!maps) {
-        return pgd_find_hole_fallback(guest_size, brk, align, offset);
+        ret = pgd_find_hole_fallback(guest_size, brk, align, offset);
+        return ret == -1 ? -1 : ret - guest_loaddr;
     }
 
     /* The first hole is before the first map entry. */

linux-user/main.c

@@ -26,6 +26,7 @@
 #include <sys/syscall.h>
 #include <sys/resource.h>
 #include <sys/shm.h>
+#include <linux/binfmts.h>
 
 #include "qapi/error.h"
 #include "qemu.h"
@@ -49,6 +50,11 @@
 #include "cpu_loop-common.h"
 #include "crypto/init.h"
 
+#ifndef AT_FLAGS_PRESERVE_ARGV0
+#define AT_FLAGS_PRESERVE_ARGV0_BIT 0
+#define AT_FLAGS_PRESERVE_ARGV0 (1 << AT_FLAGS_PRESERVE_ARGV0_BIT)
+#endif
+
 char *exec_path;
 
 int singlestep;
@@ -632,6 +638,7 @@ int main(int argc, char **argv, char **envp)
     int execfd;
     int log_mask;
     unsigned long max_reserved_va;
+    bool preserve_argv0;
 
     error_init(argv[0]);
     module_call_init(MODULE_INIT_TRACE);
@@ -688,6 +695,9 @@ int main(int argc, char **argv, char **envp)
 
     init_qemu_uname_release();
 
+    /*
+     * Manage binfmt-misc open-binary flag
+     */
     execfd = qemu_getauxval(AT_EXECFD);
     if (execfd == 0) {
         execfd = open(exec_path, O_RDONLY);
@@ -697,6 +707,20 @@ int main(int argc, char **argv, char **envp)
         }
     }
 
+    /*
+     * get binfmt_misc flags
+     */
+    preserve_argv0 = !!(qemu_getauxval(AT_FLAGS) & AT_FLAGS_PRESERVE_ARGV0);
+
+    /*
+     * Manage binfmt-misc preserve-arg[0] flag
+     *    argv[optind]     full path to the binary
+     *    argv[optind + 1] original argv[0]
+     */
+    if (optind + 1 < argc && preserve_argv0) {
+        optind++;
+    }
+
     if (cpu_model == NULL) {
         cpu_model = cpu_get_model(get_elf_eflags(execfd));
     }

linux-user/syscall.c

@@ -7890,9 +7890,9 @@ static int open_self_maps(void *cpu_env, int fd)
             count = dprintf(fd, TARGET_ABI_FMT_ptr "-" TARGET_ABI_FMT_ptr
                             " %c%c%c%c %08" PRIx64 " %s %"PRId64,
                             h2g(min), h2g(max - 1) + 1,
-                            e->is_read ? 'r' : '-',
+                            (flags & PAGE_READ) ? 'r' : '-',
-                            e->is_write ? 'w' : '-',
+                            (flags & PAGE_WRITE_ORG) ? 'w' : '-',
-                            e->is_exec ? 'x' : '-',
+                            (flags & PAGE_EXEC) ? 'x' : '-',
                             e->is_priv ? 'p' : '-',
                             (uint64_t) e->offset, e->dev, e->inode);
             if (path) {

scripts/qemu-binfmt-conf.sh

@@ -178,25 +178,27 @@ usage() {
 Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian][--systemd CPU]
                            [--help][--credential yes|no][--exportdir PATH]
                            [--persistent yes|no][--qemu-suffix SUFFIX]
+                           [--preserve-argv0 yes|no]
 
        Configure binfmt_misc to use qemu interpreter
 
-       --help:        display this usage
+       --help:          display this usage
-       --qemu-path:   set path to qemu interpreter ($QEMU_PATH)
+       --qemu-path:     set path to qemu interpreter ($QEMU_PATH)
-       --qemu-suffix: add a suffix to the default interpreter name
+       --qemu-suffix:   add a suffix to the default interpreter name
-       --debian:      don't write into /proc,
+       --debian:        don't write into /proc,
-                      instead generate update-binfmts templates
+                        instead generate update-binfmts templates
-       --systemd:     don't write into /proc,
+       --systemd:       don't write into /proc,
-                      instead generate file for systemd-binfmt.service
+                        instead generate file for systemd-binfmt.service
-                      for the given CPU. If CPU is "ALL", generate a
+                        for the given CPU. If CPU is "ALL", generate a
-                      file for all known cpus
+                        file for all known cpus
-       --exportdir:   define where to write configuration files
+       --exportdir:     define where to write configuration files
-                      (default: $SYSTEMDDIR or $DEBIANDIR)
+                        (default: $SYSTEMDDIR or $DEBIANDIR)
-       --credential:  if yes, credential and security tokens are
+       --credential:    if yes, credential and security tokens are
-                      calculated according to the binary to interpret
+                        calculated according to the binary to interpret
-       --persistent:  if yes, the interpreter is loaded when binfmt is
+       --persistent:    if yes, the interpreter is loaded when binfmt is
-                      configured and remains in memory. All future uses
+                        configured and remains in memory. All future uses
-                      are cloned from the open file.
+                        are cloned from the open file.
+       --preserve-argv0 preserve argv[0]
 
     To import templates with update-binfmts, use :
 
@@ -269,6 +271,9 @@ qemu_generate_register() {
     if [ "$PERSISTENT" = "yes" ] ; then
         flags="${flags}F"
     fi
+    if [ "$PRESERVE_ARG0" = "yes" ] ; then
+        flags="${flags}P"
+    fi
 
     echo ":qemu-$cpu:M::$magic:$mask:$qemu:$flags"
 }
@@ -330,9 +335,10 @@ DEBIANDIR="/usr/share/binfmts"
 QEMU_PATH=/usr/local/bin
 CREDENTIAL=no
 PERSISTENT=no
+PRESERVE_ARG0=no
 QEMU_SUFFIX=""
 
-options=$(getopt -o ds:Q:S:e:hc:p: -l debian,systemd:,qemu-path:,qemu-suffix:,exportdir:,help,credential:,persistent: -- "$@")
+options=$(getopt -o ds:Q:S:e:hc:p:g: -l debian,systemd:,qemu-path:,qemu-suffix:,exportdir:,help,credential:,persistent:,preserve-argv0: -- "$@")
 eval set -- "$options"
 
 while true ; do
@@ -388,6 +394,10 @@ while true ; do
         shift
         PERSISTENT="$1"
         ;;
+    -g|--preserve-argv0)
+        shift
+        PRESERVE_ARG0="$1"
+        ;;
     *)
         break
         ;;