From: YAMAMOTO Takashi <yamamoto@midokura.com>
To: qemu-devel@nongnu.org
Cc: YAMAMOTO Takashi <yamamoto@midokura.com>,
Laurent Vivier <laurent@vivier.eu>
Subject: [PATCH v2 03/11] linux-user: dup the execfd on start up
Date: Mon, 31 May 2021 14:50:10 +0900 [thread overview]
Message-ID: <20210531055019.10149-4-yamamoto@midokura.com> (raw)
In-Reply-To: <20210531055019.10149-1-yamamoto@midokura.com>
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 | 10 +++++++++-
linux-user/qemu.h | 2 ++
linux-user/syscall.c | 5 ++---
3 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/linux-user/main.c b/linux-user/main.c
index 4dfc47ad3b..a9d02f9583 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -55,6 +55,7 @@
#endif
char *exec_path;
+int exec_fd = -1;
int singlestep;
static const char *argv0;
@@ -693,7 +694,14 @@ int main(int argc, char **argv, char **envp)
* Manage binfmt-misc open-binary flag
*/
execfd = qemu_getauxval(AT_EXECFD);
- if (execfd == 0) {
+ if (execfd > 0) {
+ /*
+ * dup execfd to a global so that it can be used after loader_exec
+ * closes it.
+ */
+
+ exec_fd = dup(execfd);
+ } else {
execfd = open(exec_path, O_RDONLY);
if (execfd < 0) {
printf("Error while loading %s: %s\n", exec_path, strerror(errno));
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)
next prev parent reply other threads:[~2021-05-31 5:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-31 5:50 [PATCH v2 00/11] linux-user changes to run docker YAMAMOTO Takashi
2021-05-31 5:50 ` [PATCH v2 01/11] linux-user: handle /proc/self/exe for execve YAMAMOTO Takashi
2021-06-20 14:14 ` Laurent Vivier
2021-06-21 2:02 ` Takashi Yamamoto
2021-06-22 13:47 ` Laurent Vivier
2021-05-31 5:50 ` [PATCH v2 02/11] linux-user: Fix the execfd case of /proc/self/exe open YAMAMOTO Takashi
2021-06-20 14:16 ` Laurent Vivier
2021-06-21 1:19 ` Takashi Yamamoto
2021-05-31 5:50 ` YAMAMOTO Takashi [this message]
2021-05-31 5:50 ` [PATCH v2 04/11] linux-user: make exec_path realpath YAMAMOTO Takashi
2021-05-31 5:50 ` [PATCH v2 05/11] linux-user: Implement pivot_root YAMAMOTO Takashi
2021-06-20 14:02 ` Laurent Vivier
2021-06-20 14:05 ` Laurent Vivier
2021-05-31 5:50 ` [PATCH v2 06/11] linux-user: add get_exe_path YAMAMOTO Takashi
2021-05-31 5:50 ` [PATCH v2 07/11] linux-user: simplify is_proc_myself YAMAMOTO Takashi
2021-05-31 5:50 ` [PATCH v2 08/11] linux-user: Implement exec of /proc/$pid/exe of qemu process YAMAMOTO Takashi
2021-05-31 5:50 ` [PATCH v2 09/11] linux-user: Make the qemu detection for /proc/$pid/exe a bit conservative YAMAMOTO Takashi
2021-05-31 5:50 ` [PATCH v2 10/11] linux-user: a crude hack for libcontainer (CLONE_PARENT) [!MERGE] YAMAMOTO Takashi
2021-05-31 5:50 ` [PATCH v2 11/11] linux-user: always assume preserve_argv0 for now [!MERGE] YAMAMOTO Takashi
2021-05-31 6:07 ` [PATCH v2 00/11] linux-user changes to run docker no-reply
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