Use std::string in linux-osdata.c

I found some code in linux-osdata that manually managed a string.
Replacing this with std::string simplifies it.

Reviewed-by: John Baldwin <jhb@FreeBSD.org>

diff --git a/gdb/nat/linux-osdata.c b/gdb/nat/linux-osdata.c
index d27ddc5de23dfaa05b3e2cd32e8333f692ecf378..103b7ab26cd682b30c9a19115ef2ceb56175c345 100644 (file)
--- a/gdb/nat/linux-osdata.c
+++ b/gdb/nat/linux-osdata.c
@@ -133,55 +133,40 @@ command_from_pid (char *command, int maxlen, PID_T pid)
   command[maxlen - 1] = '\0'; /* Ensure string is null-terminated.  */
 }
 
-/* Returns the command-line of the process with the given PID. The
-   returned string needs to be freed using xfree after use.  */
+/* Returns the command-line of the process with the given PID.  */
 
-static char *
+static std::string
 commandline_from_pid (PID_T pid)
 {
   std::string pathname = string_printf ("/proc/%lld/cmdline", pid);
-  char *commandline = NULL;
+  std::string commandline;
   gdb_file_up f = gdb_fopen_cloexec (pathname, "r");
 
   if (f)
     {
-      size_t len = 0;
-
       while (!feof (f.get ()))
        {
          char buf[1024];
          size_t read_bytes = fread (buf, 1, sizeof (buf), f.get ());
 
          if (read_bytes)
-           {
-             commandline = (char *) xrealloc (commandline, len + read_bytes + 1);
-             memcpy (commandline + len, buf, read_bytes);
-             len += read_bytes;
-           }
+           commandline.append (buf, read_bytes);
        }
 
-      if (commandline)
+      if (!commandline.empty ())
        {
-         size_t i;
-
          /* Replace null characters with spaces.  */
-         for (i = 0; i < len; ++i)
-           if (commandline[i] == '\0')
-             commandline[i] = ' ';
-
-         commandline[len] = '\0';
+         for (char &c : commandline)
+           if (c == '\0')
+             c = ' ';
        }
       else
        {
          /* Return the command in square brackets if the command-line
             is empty.  */
-         commandline = (char *) xmalloc (32);
-         commandline[0] = '[';
-         command_from_pid (commandline + 1, 31, pid);
-
-         len = strlen (commandline);
-         if (len < 31)
-           strcat (commandline, "]");
+         char cmd[32];
+         command_from_pid (cmd, 31, pid);
+         commandline = std::string ("[") + cmd + "]";
        }
     }
 
@@ -349,7 +334,6 @@ linux_xfer_osdata_processes ()
          PID_T pid;
          uid_t owner;
          char user[UT_NAMESIZE];
-         char *command_line;
          int *cores;
          int task_count;
          std::string cores_str;
@@ -360,7 +344,7 @@ linux_xfer_osdata_processes ()
            continue;
 
          sscanf (dp->d_name, "%lld", &pid);
-         command_line = commandline_from_pid (pid);
+         std::string command_line = commandline_from_pid (pid);
 
          if (get_process_owner (&owner, pid) == 0)
            user_from_uid (user, sizeof (user), owner);
@@ -393,10 +377,8 @@ linux_xfer_osdata_processes ()
             "</item>",
             pid,
             user,
-            command_line ? command_line : "",
+            command_line.c_str (),
             cores_str.c_str());
-
-         xfree (command_line);
        }
 
       closedir (dirp);
@@ -487,10 +469,9 @@ linux_xfer_osdata_processgroups ()
          PID_T pid = entry.pid;
          PID_T pgid = entry.pgid;
          char leader_command[32];
-         char *command_line;
 
          command_from_pid (leader_command, sizeof (leader_command), pgid);
-         command_line = commandline_from_pid (pid);
+         std::string command_line = commandline_from_pid (pid);
 
          string_xml_appendf
            (buffer,
@@ -503,9 +484,7 @@ linux_xfer_osdata_processgroups ()
             pgid,
             leader_command,
             pid,
-            command_line ? command_line : "");
-
-         xfree (command_line);
+            command_line.c_str ());
        }
     }