[patch] incomplete patch

linux_user_syscall_proc.patch (text/plain), 10.53 KB, created by Andrew Aladjev on 2020-08-13 20:49:33 UTC

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/syscall.c b/linux-user/syscall.c
index 05f03919ff..d6b02224a9 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 */
@@ -1104,7 +1105,7 @@ static inline rlim_t target_to_host_rlim(abi_ulong target_rlim)
 {
     abi_ulong target_rlim_swap;
     rlim_t result;
-    
+
     target_rlim_swap = tswapal(target_rlim);
     if (target_rlim_swap == TARGET_RLIM_INFINITY)
         return RLIM_INFINITY;
@@ -1112,7 +1113,7 @@ static inline rlim_t target_to_host_rlim(abi_ulong target_rlim)
     result = target_rlim_swap;
     if (target_rlim_swap != (rlim_t)result)
         return RLIM_INFINITY;
-    
+
     return result;
 }
 #endif
@@ -1122,13 +1123,13 @@ static inline abi_ulong host_to_target_rlim(rlim_t rlim)
 {
     abi_ulong target_rlim_swap;
     abi_ulong result;
-    
+
     if (rlim == RLIM_INFINITY || rlim != (abi_long)rlim)
         target_rlim_swap = TARGET_RLIM_INFINITY;
     else
         target_rlim_swap = rlim;
     result = tswapal(target_rlim_swap);
-    
+
     return result;
 }
 #endif
@@ -1615,9 +1616,9 @@ static inline abi_long target_to_host_cmsg(struct msghdr *msgh,
     abi_ulong target_cmsg_addr;
     struct target_cmsghdr *target_cmsg, *target_cmsg_start;
     socklen_t space = 0;
-    
+
     msg_controllen = tswapal(target_msgh->msg_controllen);
-    if (msg_controllen < sizeof (struct target_cmsghdr)) 
+    if (msg_controllen < sizeof (struct target_cmsghdr))
         goto the_end;
     target_cmsg_addr = tswapal(target_msgh->msg_control);
     target_cmsg = lock_user(VERIFY_READ, target_cmsg_addr, msg_controllen, 1);
@@ -1703,7 +1704,7 @@ static inline abi_long host_to_target_cmsg(struct target_msghdr *target_msgh,
     socklen_t space = 0;
 
     msg_controllen = tswapal(target_msgh->msg_controllen);
-    if (msg_controllen < sizeof (struct target_cmsghdr)) 
+    if (msg_controllen < sizeof (struct target_cmsghdr))
         goto the_end;
     target_cmsg_addr = tswapal(target_msgh->msg_control);
     target_cmsg = lock_user(VERIFY_WRITE, target_cmsg_addr, msg_controllen, 0);
@@ -5750,7 +5751,7 @@ abi_long do_set_thread_area(CPUX86State *env, abi_ulong ptr)
     }
     unlock_user_struct(target_ldt_info, ptr, 1);
 
-    if (ldt_info.entry_number < TARGET_GDT_ENTRY_TLS_MIN || 
+    if (ldt_info.entry_number < TARGET_GDT_ENTRY_TLS_MIN ||
         ldt_info.entry_number > TARGET_GDT_ENTRY_TLS_MAX)
            return -TARGET_EINVAL;
     seg_32bit = ldt_info.flags & 1;
@@ -5828,7 +5829,7 @@ static abi_long do_get_thread_area(CPUX86State *env, abi_ulong ptr)
     lp = (uint32_t *)(gdt_table + idx);
     entry_1 = tswap32(lp[0]);
     entry_2 = tswap32(lp[1]);
-    
+
     read_exec_only = ((entry_2 >> 9) & 1) ^ 1;
     contents = (entry_2 >> 10) & 3;
     seg_not_present = ((entry_2 >> 15) & 1) ^ 1;
@@ -5844,8 +5845,8 @@ static abi_long do_get_thread_area(CPUX86State *env, abi_ulong ptr)
         (read_exec_only << 3) | (limit_in_pages << 4) |
         (seg_not_present << 5) | (useable << 6) | (lm << 7);
     limit = (entry_1 & 0xffff) | (entry_2  & 0xf0000);
-    base_addr = (entry_1 >> 16) | 
-        (entry_2 & 0xff000000) | 
+    base_addr = (entry_1 >> 16) |
+        (entry_2 & 0xff000000) |
         ((entry_2 & 0xff) << 16);
     target_ldt_info->base_addr = tswapal(base_addr);
     target_ldt_info->limit = tswap32(limit);
@@ -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)
 {
@@ -7460,18 +7429,18 @@ 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")) {
+    if (is_proc_myself_exe(pathname)) {
         int execfd = qemu_getauxval(AT_EXECFD);
         return execfd ? execfd : safe_openat(dirfd, exec_path, flags, mode);
     }
@@ -9031,7 +9000,7 @@ 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 +9029,7 @@ 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) ;
@@ -10847,7 +10816,7 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
         return get_errno(fchown(arg1, low2highuid(arg2), low2highgid(arg3)));
 #if defined(TARGET_NR_fchownat)
     case TARGET_NR_fchownat:
-        if (!(p = lock_user_string(arg2))) 
+        if (!(p = lock_user_string(arg2)))
             return -TARGET_EFAULT;
         ret = get_errno(fchownat(arg1, p, low2highuid(arg3),
                                  low2highgid(arg4), arg5));
diff --git a/linux-user/syscall_proc.c b/linux-user/syscall_proc.c
new file mode 100644
index 0000000000..869102f3fe
--- /dev/null
+++ b/linux-user/syscall_proc.c
@@ -0,0 +1,95 @@
+#include "syscall_proc.h"
+#include "qemu/osdep.h"
+#include "elf.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;
+}
+
+int is_proc_myself_exe(const char *path)
+{
+    char *scope_path = scope_to_proc_myself(path);
+    if (scope_path == NULL) {
+        return 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/#{global_execfd}" only.
+
+    if (strcmp(scope_path, "exe") == 0) {
+        return 1;
+    }
+
+    if (STARTS_WITH(scope_path, "fd/")) {
+        scope_path += strlen("fd/");
+
+        int execfd = qemu_getauxval(AT_EXECFD);
+        if (strlen(scope_path) >= 1 && *scope_path >= '1' && *scope_path <= '9' && execfd) {
+            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