2005-11-30 Michael Snyder <msnyder@redhat.com>

	* linux-fork.c (struct fork_info): Add fields for saving
	file offsets of all open file descriptors.
	(free_fork): Free storage for file offsets.
	(call_lseek): New function.  Call lseek in the inferior.
	(fork_save_infrun_state): Use /proc and call_lseek to save
	file offsets for all open file descriptors in inferior.
	(fork_load_infrun_state): Use call_lseek to restore file offsets.
	(restart_command): Fix oversight, save fork id.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 50ccc9f6aa0002f22908f6bd7d351563f561e6ae..b60a5df3b55f015cd3b77dcd57ec0b922df275c5 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,14 @@
+2005-11-30  Michael Snyder  <msnyder@redhat.com>
+
+       * linux-fork.c (struct fork_info): Add fields for saving
+       file offsets of all open file descriptors.
+       (free_fork): Free storage for file offsets.
+       (call_lseek): New function.  Call lseek in the inferior.
+       (fork_save_infrun_state): Use /proc and call_lseek to save
+       file offsets for all open file descriptors in inferior.
+       (fork_load_infrun_state): Use call_lseek to restore file offsets.
+       (restart_command): Fix oversight, save fork id.
+
 2005-11-29  Michael Snyder  <msnyder@redhat.com>
 
        * linux-fork.c (process_command): New command, new function.

diff --git a/gdb/linux-fork.c b/gdb/linux-fork.c
index f9bd7a6dbbb360ae09fa7de88a298cb8ac923cd5..a922b562397d4f2e3face8bd404222879f5bd950 100644 (file)
--- a/gdb/linux-fork.c
+++ b/gdb/linux-fork.c
@@ -29,6 +29,9 @@
 
 #include <sys/ptrace.h>
 #include <sys/wait.h>
+#include <sys/param.h>         /* For MAXPATHLEN */
+#include <dirent.h>
+#include <ctype.h>
 
 struct fork_info *fork_list;
 static int highest_fork_num;
@@ -48,6 +51,8 @@ struct fork_info
                                   having to actually switch contexts.  */
   int clobber_regs;            /* True if we should restore saved regs.  */
   int been_restarted;          /* One time flag.  */
+  off_t *filepos;
+  int maxfd;
 };
 
 /*
@@ -89,6 +94,8 @@ free_fork (struct fork_info *fp)
     {
       if (fp->savedregs)
        regcache_xfree (fp->savedregs);
+      if (fp->filepos)
+       xfree (fp->filepos);
       xfree (fp);
     }
 }
@@ -199,17 +206,41 @@ init_fork_list (void)
  * Fork list <-> gdb interface:
  */
 
+/* call_lseek -- utility function for fork_load/fork_save.  
+   Calls lseek in the (current) inferior process.  */
+static off_t
+call_lseek (int fd, off_t offset, int whence)
+{
+  char exp[80];
+
+  snprintf (&exp[0], sizeof (exp), "lseek (%d, %ld, %d)",
+           fd, (long) offset, whence);
+  return (off_t) parse_and_eval_long (&exp[0]);
+}
+
 /* Load infrun state for the fork PTID.  */
 
 static void
 fork_load_infrun_state (struct fork_info *fp)
 {
   extern void nullify_last_target_wait_ptid ();
+  int i;
 
   if (fp->savedregs && fp->clobber_regs)
     regcache_cpy (current_regcache, fp->savedregs);
 
   nullify_last_target_wait_ptid ();
+
+  /* Now restore the file positions of open file descriptors.  */
+  if (fp->filepos)
+    {
+      for (i = 0; i <= fp->maxfd; i++)
+       if (fp->filepos[i] != (off_t) -1)
+         call_lseek (i, fp->filepos[i], SEEK_SET);
+      /* NOTE: I can get away with using SEEK_SET and SEEK_CUR because
+        this is native-only.  If it ever has to be cross, we'll have
+        to rethink this.  */
+    }
 }
 
 /* Save infrun state for the fork PTID.
@@ -219,11 +250,52 @@ fork_load_infrun_state (struct fork_info *fp)
 extern void
 fork_save_infrun_state (struct fork_info *fp, int clobber_regs)
 {
+  char path[MAXPATHLEN];
+  struct dirent *de;
+  DIR *d;
+
   if (fp->savedregs)
     regcache_xfree (fp->savedregs);
 
   fp->savedregs = regcache_dup (current_regcache);
   fp->clobber_regs = clobber_regs;
+
+  if (clobber_regs)
+    {
+      /* Now save the 'state' (file position) of all open file descriptors.
+        Unfortunately fork does not take care of that for us...  */
+      snprintf (path, MAXPATHLEN, "/proc/%ld/fd", (long) PIDGET (fp->ptid));
+      if ((d = opendir (path)) != NULL)
+       {
+         long tmp;
+
+         fp->maxfd = 0;
+         while ((de = readdir (d)) != NULL)
+           {
+             /* Count open file descriptors (actually find highest
+                numbered).  */
+             tmp = strtol (&de->d_name[0], NULL, 10);
+             if (fp->maxfd < tmp)
+               fp->maxfd = tmp;
+           }
+         /* Allocate array of file positions.  */
+         fp->filepos = xrealloc (fp->filepos, 
+                                 (fp->maxfd + 1) * sizeof (*fp->filepos));
+
+         /* Initialize to -1 (invalid).  */
+         for (tmp = 0; tmp <= fp->maxfd; tmp++)
+           fp->filepos[tmp] = -1;
+
+         /* Now find actual file positions.  */
+         rewinddir (d);
+         while ((de = readdir (d)) != NULL)
+           if (isdigit (de->d_name[0]))
+             {
+               tmp = strtol (&de->d_name[0], NULL, 10);
+               fp->filepos[tmp] = call_lseek (tmp, 0, SEEK_CUR);
+             }
+       }
+    }
 }
 
 /* linux_fork_killall.  Let God sort 'em out...  */
@@ -342,7 +414,7 @@ info_forks_command (char *arg, int from_tty)
          printf_filtered ("  ");
          regcache_raw_read_unsigned (fp->savedregs, PC_REGNUM, &pc);
        }
-      printf_filtered ("%d %s", fp->num, target_tid_to_str (fp->ptid));
+      printf_filtered ("%d %s", fp->num, target_pid_to_str (fp->ptid));
       if (fp->num == 0)
        printf_filtered (" (main process)");
       printf_filtered (" at ");
@@ -505,7 +577,7 @@ restart_command (char *args, int from_tty)
   if (!args || !*args)
     error ("Requires argument (checkpoint id, see info checkpoints)");
 
-  if ((find_fork_id (parse_and_eval_long (args))) == NULL)
+  if ((fp = find_fork_id (parse_and_eval_long (args))) == NULL)
     error ("Not found: checkpoint id %s", args);
 
   linux_fork_context (fp, from_tty);