>From 738f6ec4598b4618acd7ecbd11e5d250a82f28b7 Mon Sep 17 00:00:00 2001
From: Andrew Aladjev <aladjev.and...@gmail.com>
Date: Mon, 17 Aug 2020 01:20:03 +0300
Subject: [PATCH] fixed proc myself (linux user) for musl
Signed-off-by: Andrew Aladjev <aladjev.and...@gmail.com>
---
linux-user/Makefile.objs | 5 +-
linux-user/elfload.c | 7 ++-
linux-user/exit.c | 7 ++-
linux-user/main.c | 2 +-
linux-user/qemu.h | 1 +
linux-user/syscall.c | 63 ++++++++---------------
linux-user/syscall_proc.c | 102 ++++++++++++++++++++++++++++++++++++++
linux-user/syscall_proc.h | 8 +++
8 files changed, 146 insertions(+), 49 deletions(-)
create mode 100644 linux-user/syscall_proc.c
create mode 100644 linux-user/syscall_proc.h
diff --git a/linux-user/Makefile.objs b/linux-user/Makefile.objs
index 1940910a73..ad84380738 100644
--- a/linux-user/Makefile.objs
+++ b/linux-user/Makefile.objs
@@ -1,7 +1,8 @@
obj-y = main.o syscall.o strace.o mmap.o signal.o \
elfload.o linuxload.o uaccess.o uname.o \
- safe-syscall.o $(TARGET_ABI_DIR)/signal.o \
- $(TARGET_ABI_DIR)/cpu_loop.o exit.o fd-trans.o
+ safe-syscall.o syscall_proc.o \
+ $(TARGET_ABI_DIR)/cpu_loop.o $(TARGET_ABI_DIR)/signal.o \
+ exit.o fd-trans.o
obj-$(TARGET_HAS_BFLT) += flatload.o
obj-$(TARGET_I386) += vm86.o
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 619c054cc4..201db61d91 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2319,7 +2319,10 @@ exit_errmsg:
buffer is sufficiently aligned to present no problems to the host
in accessing data at aligned offsets within the buffer.
- On return: INFO values will be filled in, as necessary or available. */
+ On return: INFO values will be filled in, as necessary or available.
+
+ WARNING: this function won't close "image_fd".
+*/
static void load_elf_image(const char *image_name, int image_fd,
struct image_info *info, char **pinterp_name,
@@ -2576,7 +2579,6 @@ static void load_elf_image(const char *image_name,
int image_fd,
mmap_unlock();
- close(image_fd);
return;
exit_read:
@@ -2610,6 +2612,7 @@ static void load_elf_interp(const char *filename,
struct image_info *info,
}
load_elf_image(filename, fd, info, NULL, bprm_buf);
+ close(fd);
return;
exit_perror:
diff --git a/linux-user/exit.c b/linux-user/exit.c
index 1594015444..f0626fc432 100644
--- a/linux-user/exit.c
+++ b/linux-user/exit.c
@@ -28,12 +28,15 @@ extern void __gcov_dump(void);
void preexit_cleanup(CPUArchState *env, int code)
{
+ close(execfd);
+
#ifdef CONFIG_GPROF
_mcleanup();
#endif
#ifdef CONFIG_GCOV
__gcov_dump();
#endif
- gdb_exit(env, code);
- qemu_plugin_atexit_cb();
+
+ gdb_exit(env, code);
+ qemu_plugin_atexit_cb();
}
diff --git a/linux-user/main.c b/linux-user/main.c
index 22578b1633..9cc6c1e6da 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -48,6 +48,7 @@
#include "crypto/init.h"
char *exec_path;
+int execfd;
int singlestep;
static const char *argv0;
@@ -628,7 +629,6 @@ int main(int argc, char **argv, char **envp)
int target_argc;
int i;
int ret;
- int execfd;
int log_mask;
unsigned long max_reserved_va;
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 792c74290f..d822f2b9df 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -156,6 +156,7 @@ typedef struct TaskState {
} __attribute__((aligned(16))) TaskState;
extern char *exec_path;
+extern int execfd;
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 05f03919ff..af86385281 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -122,6 +122,7 @@
#include "qapi/error.h"
#include "fd-trans.h"
#include "tcg/tcg.h"
+#include "syscall_proc.h"
#ifndef CLONE_IO
#define CLONE_IO 0x80000000 /* Clone io context */
@@ -7353,38 +7354,6 @@ static int open_self_auxv(void *cpu_env, int fd)
return 0;
}
-static int is_proc_myself(const char *filename, const char *entry)
-{
- if (!strncmp(filename, "/proc/", strlen("/proc/"))) {
- filename += strlen("/proc/");
- if (!strncmp(filename, "self/", strlen("self/"))) {
- filename += strlen("self/");
- } else if (*filename >= '1' && *filename <= '9') {
- char myself[80];
- snprintf(myself, sizeof(myself), "%d/", getpid());
- if (!strncmp(filename, myself, strlen(myself))) {
- filename += strlen(myself);
- } else {
- return 0;
- }
- } else {
- return 0;
- }
- if (!strcmp(filename, entry)) {
- return 1;
- }
- }
- return 0;
-}
-
-#if defined(HOST_WORDS_BIGENDIAN) != defined(TARGET_WORDS_BIGENDIAN) || \
- defined(TARGET_SPARC) || defined(TARGET_M68K)
-static int is_proc(const char *filename, const char *entry)
-{
- return strcmp(filename, entry) == 0;
-}
-#endif
-
#if defined(HOST_WORDS_BIGENDIAN) != defined(TARGET_WORDS_BIGENDIAN)
static int open_net_route(void *cpu_env, int fd)
{
@@ -7460,20 +7429,19 @@ static int do_openat(void *cpu_env, int dirfd,
const char *pathname, int flags,
{ "auxv", open_self_auxv, is_proc_myself },
{ "cmdline", open_self_cmdline, is_proc_myself },
#if defined(HOST_WORDS_BIGENDIAN) != defined(TARGET_WORDS_BIGENDIAN)
- { "/proc/net/route", open_net_route, is_proc },
+ { "net/route", open_net_route, is_proc },
#endif
#if defined(TARGET_SPARC)
- { "/proc/cpuinfo", open_cpuinfo, is_proc },
+ { "cpuinfo", open_cpuinfo, is_proc },
#endif
#if defined(TARGET_M68K)
- { "/proc/hardware", open_hardware, is_proc },
+ { "hardware", open_hardware, is_proc },
#endif
{ NULL, NULL, NULL }
};
- if (is_proc_myself(pathname, "exe")) {
- int execfd = qemu_getauxval(AT_EXECFD);
- return execfd ? execfd : safe_openat(dirfd, exec_path, flags,
mode);
+ if (is_proc_myself_exe(pathname)) {
+ return execfd;
}
for (fake_open = fakes; fake_open->filename; fake_open++) {
@@ -7728,8 +7696,19 @@ static abi_long do_syscall1(void *cpu_env, int num,
abi_long arg1,
return ret;
#endif
case TARGET_NR_close:
- fd_trans_unregister(arg1);
- return get_errno(close(arg1));
+ {
+ int fd = arg1;
+ if (fd == execfd) {
+ /*
+ * We don't need to close execfd.
+ * It will be closed on QEMU exit.
+ */
+ return 0;
+ }
+
+ fd_trans_unregister(fd);
+ return get_errno(close(fd));
+ }
case TARGET_NR_brk:
return do_brk(arg1);
@@ -9031,7 +9010,7 @@ static abi_long do_syscall1(void *cpu_env, int num,
abi_long arg1,
} else if (!arg3) {
/* Short circuit this for the magic exe check. */
ret = -TARGET_EINVAL;
- } else if (is_proc_myself((const char *)p, "exe")) {
+ } else if (is_proc_myself_exe((const char *)p)) {
char real[PATH_MAX], *temp;
temp = realpath(exec_path, real);
/* Return value is # of bytes that we wrote to the buffer.
*/
@@ -9060,7 +9039,7 @@ static abi_long do_syscall1(void *cpu_env, int num,
abi_long arg1,
p2 = lock_user(VERIFY_WRITE, arg3, arg4, 0);
if (!p || !p2) {
ret = -TARGET_EFAULT;
- } else if (is_proc_myself((const char *)p, "exe")) {
+ } else if (is_proc_myself_exe((const char *)p)) {
char real[PATH_MAX], *temp;
temp = realpath(exec_path, real);
ret = temp == NULL ? get_errno(-1) : strlen(real) ;
diff --git a/linux-user/syscall_proc.c b/linux-user/syscall_proc.c
new file mode 100644
index 0000000000..8688459c7d
--- /dev/null
+++ b/linux-user/syscall_proc.c
@@ -0,0 +1,102 @@
+#include "qemu/osdep.h"
+#include "elf.h"
+
+#include "syscall_proc.h"
+#include "qemu.h"
+
+#define PROC "/proc/"
+#define SELF "self/"
+
+#define STARTS_WITH(path, CONSTANT) ( \
+ strlen(path) >= strlen(CONSTANT) && \
+ strncmp(path, CONSTANT, strlen(CONSTANT)) == 0 \
+)
+
+static inline char *scope_to_proc(const char *path)
+{
+ if (STARTS_WITH(path, PROC)) {
+ return (char *)path + strlen(PROC);
+ }
+
+ return NULL;
+}
+
+static inline char *scope_to_proc_myself(const char *path)
+{
+ char *scope_path = scope_to_proc(path);
+ if (scope_path == NULL) {
+ return NULL;
+ }
+
+ if (STARTS_WITH(scope_path, SELF)) {
+ return scope_path + strlen(SELF);
+ }
+
+ if (strlen(scope_path) >= 1 &&
+ *scope_path >= '1' && *scope_path <= '9') {
+ char pid_path[80];
+ snprintf(pid_path, sizeof(pid_path), "%d/", getpid());
+ if (STARTS_WITH(scope_path, pid_path)) {
+ return scope_path + strlen(pid_path);
+ }
+ }
+
+ return NULL;
+}
+
+int is_proc(const char *path, const char *entry)
+{
+ char *scope_path = scope_to_proc(path);
+ if (scope_path == NULL) {
+ return 0;
+ }
+
+ return strcmp(scope_path, entry) == 0;
+}
+
+int is_proc_myself(const char *path, const char *entry)
+{
+ char *scope_path = scope_to_proc_myself(path);
+ if (scope_path == NULL) {
+ return 0;
+ }
+
+ return strcmp(scope_path, entry) == 0;
+}
+
+/*
+ * Kernel creates "fd/#{number}" link after opening "exe" link.
+ * Both "exe" and "fd/#{number}" can be used by application.
+ *
+ * Kernel can provide infinite amount of fd numbers.
+ * QEMU is going to always return single global execfd.
+ *
+ * So we need to check "exe" and "fd/#{execfd}" only.
+ */
+
+int is_proc_myself_exe(const char *path)
+{
+ char *scope_path = scope_to_proc_myself(path);
+ if (scope_path == NULL) {
+ return 0;
+ }
+
+ if (strcmp(scope_path, "exe") == 0) {
+ return 1;
+ }
+
+ if (STARTS_WITH(scope_path, "fd/")) {
+ scope_path += strlen("fd/");
+
+ if (strlen(scope_path) >= 1 &&
+ *scope_path >= '1' && *scope_path <= '9') {
+ char execfd_path[80];
+ snprintf(execfd_path, sizeof(execfd_path), "%d", execfd);
+ if (strcmp(scope_path, execfd_path) == 0) {
+ return 1;
+ }
+ }
+ }
+
+ return 0;
+}
diff --git a/linux-user/syscall_proc.h b/linux-user/syscall_proc.h
new file mode 100644
index 0000000000..f0e59c0e96
--- /dev/null
+++ b/linux-user/syscall_proc.h
@@ -0,0 +1,8 @@
+#ifndef SYSCALL_PROC_H
+#define SYSCALL_PROC_H
+
+int is_proc(const char *path, const char *entry);
+int is_proc_myself(const char *path, const char *entry);
+int is_proc_myself_exe(const char *path);
+
+#endif
--
2.26.2
