Update Android port

* exec/config.h.in (__bool_true_false_are_defined):
* exec/configure.ac (REENTRANT): New definition.
(READLINKAT_SYSCALL, READLINK_SYSCALL): New defines.  Set on all
hosts.
* exec/exec.c (MIN, MAX): Remove redundant declarations.  Move
to config.h.
(exec_0): Copy name of executable into NAME when !REENTRANT.
* exec/exec.h (struct exec_tracee): New struct `exec_file'.
* exec/trace.c (remove_tracee, handle_exec, handle_readlinkat)
(process_system_call, after_fork): Handle readlinkat system
calls.

1 files changed, 37 insertions, 15 deletions

diff --git a/exec/exec.c b/exec/exec.c
index 7f2cc75338b..17051428658 100644
--- a/exec/exec.c
+++ b/exec/exec.c
@@ -31,14 +31,6 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #include <sys/param.h>
 #include <sys/mman.h>
 
-#ifndef MIN
-#define MIN(a, b) ((a) < (b) ? (a) : (b))
-#endif /* MIN */
-
-#ifndef MAX
-#define MAX(a, b) ((a) < (b) ? (b) : (a))
-#endif /* MAX */
-
 #include "exec.h"
 
 #if defined __mips__ && !defined MIPS_NABI
@@ -938,6 +930,10 @@ format_pid (char *in, unsigned int pid)
    with #!; in that case, find the program to open and use that
    instead.
 
+   If REENTRANT is not defined, NAME is actually a buffer of size
+   PATH_MAX + 80.  In that case, copy over the file name actually
+   opened.
+
    Next, read the executable header, and add the necessary memory
    mappings for each file.  Finally, return the action data and its
    size in *SIZE.
@@ -948,7 +944,7 @@ format_pid (char *in, unsigned int pid)
    Value is NULL upon failure, with errno set accordingly.  */
 
 char *
-exec_0 (const char *name, struct exec_tracee *tracee,
+exec_0 (char *name, struct exec_tracee *tracee,
         size_t *size, USER_REGS_STRUCT *regs)
 {
   int fd, rc, i;
@@ -961,7 +957,8 @@ exec_0 (const char *name, struct exec_tracee *tracee,
 #if defined __mips__ && !defined MIPS_NABI
   int fpu_mode;
 #endif /* defined __mips__ && !defined MIPS_NABI */
-  char buffer[PATH_MAX + 80], *rewrite;
+  char buffer[80], buffer1[PATH_MAX + 80], *rewrite;
+  ssize_t link_size;
   size_t remaining;
 
   /* If name is not absolute, then make it relative to TRACEE's
@@ -971,18 +968,43 @@ exec_0 (const char *name, struct exec_tracee *tracee,
     {
       /* Clear `buffer'.  */
       memset (buffer, 0, sizeof buffer);
+      memset (buffer1, 0, sizeof buffer);
 
       /* Copy over /proc, the PID, and /cwd/.  */
       rewrite = stpcpy (buffer, "/proc/");
       rewrite = format_pid (rewrite, tracee->pid);
-      rewrite = stpcpy (rewrite, "/cwd/");
+      stpcpy (rewrite, "/cwd");
+
+      /* Resolve this symbolic link.  */
+
+      link_size = readlink (buffer, buffer1,
+                            PATH_MAX + 1);
+
+      if (link_size < 0)
+        return NULL;
+
+      /* Check that the name is a reasonable size.  */
+
+      if (link_size > PATH_MAX)
+        {
+          /* The name is too long.  */
+          errno = ENAMETOOLONG;
+          return NULL;
+        }
+
+      /* Add a directory separator if necessary.  */
+      
+      if (!link_size || buffer1[link_size - 1] != '/')
+        buffer1[link_size] = '/', link_size++;
 
-      /* Make sure there is enough free space.  */
-      remaining = buffer + sizeof buffer - rewrite - 1;
+      rewrite = buffer1 + link_size;
+      remaining = buffer1 + sizeof buffer1 - rewrite - 1;
       rewrite = stpncpy (rewrite, name, remaining);
 
-      /* Replace name with buffer.  */
-      name = buffer;
+      /* Replace name with buffer1.  */
+#ifndef REENTRANT
+      strcpy (name, buffer1);
+#endif /* REENTRANT */
     }
 
   fd = open (name, O_RDONLY);