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[PATCH 4/5] linux-user: dup the execfd on start up
From: |
YAMAMOTO Takashi |
Subject: |
[PATCH 4/5] linux-user: dup the execfd on start up |
Date: |
Mon, 24 May 2021 13:54:10 +0900 |
So that it can be used for other purposes (e.g. syscall.c)
after the elf loader closed it.
Signed-off-by: YAMAMOTO Takashi <yamamoto@midokura.com>
---
linux-user/main.c | 8 ++++++++
linux-user/qemu.h | 2 ++
linux-user/syscall.c | 5 ++---
3 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/linux-user/main.c b/linux-user/main.c
index 1f9f4e3820..86ddba8b62 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -56,6 +56,7 @@
char *exec_path;
char exec_path_store[PATH_MAX];
+int exec_fd = -1;
int singlestep;
static const char *argv0;
@@ -833,6 +834,13 @@ int main(int argc, char **argv, char **envp)
cpu->opaque = ts;
task_settid(ts);
+ /*
+ * dup execfd to a global so that it can be used after loader_exec
+ * closes it.
+ */
+
+ exec_fd = dup(execfd);
+
ret = loader_exec(execfd, exec_path, target_argv, target_environ, regs,
info, &bprm);
if (ret != 0) {
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 3b0b6b75fe..ee4e9a1779 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -160,6 +160,8 @@ typedef struct TaskState {
} __attribute__((aligned(16))) TaskState;
extern char *exec_path;
+extern int exec_fd;
+
void init_task_state(TaskState *ts);
void task_settid(TaskState *);
void stop_all_tasks(void);
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 14a63518e2..2947e79dc0 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8117,12 +8117,11 @@ static int do_openat(void *cpu_env, int dirfd, const
char *pathname, int flags,
};
if (is_proc_myself(pathname, "exe")) {
- int execfd = qemu_getauxval(AT_EXECFD);
- if (execfd) {
+ if (exec_fd != -1) {
char filename[PATH_MAX];
int ret;
- snprintf(filename, sizeof(filename), "/proc/self/fd/%d", execfd);
+ snprintf(filename, sizeof(filename), "/proc/self/fd/%d", exec_fd);
ret = safe_openat(dirfd, filename, flags, mode);
if (ret != -1) {
return ret;
--
2.21.1 (Apple Git-122.3)
- [PATCH 0/5] linux-user changes to run docker, YAMAMOTO Takashi, 2021/05/24
- [PATCH 1/5] linux-user: handle /proc/self/exe for execve, YAMAMOTO Takashi, 2021/05/24
- [PATCH 3/5] linux-user: Fix the execfd case of /proc/self/exe open, YAMAMOTO Takashi, 2021/05/24
- [PATCH 4/5] linux-user: dup the execfd on start up,
YAMAMOTO Takashi <=
- [PATCH 5/5] linux-user: Implement pivot_root, YAMAMOTO Takashi, 2021/05/24
- Re: [PATCH 0/5] linux-user changes to run docker, Alex Bennée, 2021/05/24