Detect asprintf's ENOMEM in procfs.c rather than everywhere

* procfs.h: Make CONTENTS_LEN an ssize_t rather than a size_t,
  and document the change.
* procfs.c (procfs_get_contents): Initialize CONTENTS_LEN to a
  negative value, and fail with ENOMEM if it's still negative after the
  callback returns.  (everywhere): Update to ssize_t.
* dircat.c, netfs.c, process.c,
  procfs_dir.c, proclist.c, rootdir.c: Update to
  ssize_t and the new GET_CONTENTS semantics.

8 files changed, 59 insertions, 68 deletions

diff --git a/dircat.c b/dircat.c
index 93bb2fed..bb66508a 100644
--- a/dircat.c
+++ b/dircat.c
@@ -8,7 +8,7 @@ struct dircat_node
 };
 
 static error_t
-dircat_get_contents (void *hook, char **contents, size_t *contents_len)
+dircat_get_contents (void *hook, char **contents, ssize_t *contents_len)
 {
   struct dircat_node *dcn = hook;
   int i, sz, pos;
@@ -20,7 +20,7 @@ dircat_get_contents (void *hook, char **contents, size_t *contents_len)
   for (i=0; dcn->dirs[i]; i++)
     {
       char *subcon;
-      size_t sublen;
+      ssize_t sublen;
 
       err = procfs_get_contents (dcn->dirs[i], &subcon, &sublen);
       if (err)
diff --git a/netfs.c b/netfs.c
index 6fd82a00..e41e0623 100644
--- a/netfs.c
+++ b/netfs.c
@@ -30,7 +30,7 @@ int netfs_maxsymlinks = PROCFS_MAXSYMLINKS;
 error_t netfs_validate_stat (struct node *np, struct iouser *cred)
 {
   char *contents;
-  size_t contents_len;
+  ssize_t contents_len;
   error_t err;
 
   /* Only symlinks need to have their size filled, before a read is
@@ -54,7 +54,7 @@ error_t netfs_attempt_read (struct iouser *cred, struct node *np,
 			    loff_t offset, size_t *len, void *data)
 {
   char *contents;
-  size_t contents_len;
+  ssize_t contents_len;
   error_t err;
 
   err = procfs_get_contents (np, &contents, &contents_len);
@@ -79,7 +79,7 @@ error_t netfs_attempt_readlink (struct iouser *user, struct node *np,
 				char *buf)
 {
   char *contents;
-  size_t contents_len;
+  ssize_t contents_len;
   error_t err;
 
   err = procfs_get_contents (np, &contents, &contents_len);
@@ -137,7 +137,7 @@ error_t netfs_get_dirents (struct iouser *cred, struct node *dir,
 			   vm_size_t bufsize, int *amt)
 {
   char *contents;
-  size_t contents_len;
+  ssize_t contents_len;
   error_t err;
  
   err = procfs_get_contents (dir, &contents, &contents_len);
diff --git a/process.c b/process.c
index fa795522..624f79e7 100644
--- a/process.c
+++ b/process.c
@@ -12,18 +12,18 @@
 
 /* Implementations for the process_file_desc.get_contents callback.  */
 
-static char *
-process_file_gc_cmdline (struct proc_stat *ps, size_t *len)
+static ssize_t
+process_file_gc_cmdline (struct proc_stat *ps, char **contents)
 {
-  *len = proc_stat_args_len(ps);
-  return proc_stat_args(ps);
+  *contents = proc_stat_args(ps);
+  return proc_stat_args_len(ps);
 }
 
-static char *
-process_file_gc_environ (struct proc_stat *ps, size_t *len)
+static ssize_t
+process_file_gc_environ (struct proc_stat *ps, char **contents)
 {
-  *len = proc_stat_args_len(ps);
-  return proc_stat_args(ps);
+  *contents = proc_stat_env(ps);
+  return proc_stat_env_len(ps);
 }
 
 static char state_char (struct proc_stat *ps)
@@ -71,17 +71,16 @@ static long long int jiff_tv (time_value_t tv)
   return usecs * 100 / 1000000;
 }
 
-static char *
-process_file_gc_stat (struct proc_stat *ps, size_t *len)
+static ssize_t
+process_file_gc_stat (struct proc_stat *ps, char **contents)
 {
   struct procinfo *pi = proc_stat_proc_info (ps);
   task_basic_info_t tbi = proc_stat_task_basic_info (ps);
   thread_basic_info_t thbi = proc_stat_thread_basic_info (ps);
-  char *contents;
 
   /* See proc(5) for more information about the contents of each field for the
      Linux procfs.  */
-  *len = asprintf (&contents,
+  return asprintf (contents,
       "%d (%s) %c "		/* pid, command, state */
       "%d %d %d "		/* ppid, pgid, session */
       "%d %d "			/* controling tty stuff */
@@ -122,31 +121,23 @@ process_file_gc_stat (struct proc_stat *ps, size_t *len)
       0,
       0, 0,
       0LL);
-
-  return len >= 0 ? contents : NULL;
 }
 
-static char *
-process_file_gc_statm (struct proc_stat *ps, size_t *len)
+static ssize_t
+process_file_gc_statm (struct proc_stat *ps, char **contents)
 {
   task_basic_info_t tbi = proc_stat_task_basic_info (ps);
-  char *contents;
-
-  *len = asprintf (&contents,
+  return asprintf (contents,
       "%lu %lu 0 0 0 0 0\n",
       tbi->virtual_size  / sysconf(_SC_PAGE_SIZE),
       tbi->resident_size / sysconf(_SC_PAGE_SIZE));
-
-  return len >= 0 ? contents : NULL;
 }
 
-static char *
-process_file_gc_status (struct proc_stat *ps, size_t *len)
+static ssize_t
+process_file_gc_status (struct proc_stat *ps, char **contents)
 {
   task_basic_info_t tbi = proc_stat_task_basic_info (ps);
-  char *contents;
-
-  *len = asprintf (&contents,
+  return asprintf (contents,
       "Name:\t%s\n"
       "State:\t%s\n"
       "Tgid:\t%u\n"
@@ -172,8 +163,6 @@ process_file_gc_status (struct proc_stat *ps, size_t *len)
       tbi->resident_size / 1024,
       tbi->resident_size / 1024,
       proc_stat_num_threads (ps));
-
-  return len >= 0 ? contents : NULL;
 }
 
 
@@ -186,7 +175,7 @@ struct process_file_desc
 
   /* Once we have acquired the necessary information, there can be only
      memory allocation errors, hence this simplified signature.  */
-  char *(*get_contents) (struct proc_stat *ps, size_t *len);
+  ssize_t (*get_contents) (struct proc_stat *ps, char **contents);
 
   /* The cmdline and environ contents don't need any cleaning since they are
      part of a proc_stat structure.  */
@@ -204,7 +193,7 @@ struct process_file_node
 };
 
 static error_t
-process_file_get_contents (void *hook, char **contents, size_t *contents_len)
+process_file_get_contents (void *hook, char **contents, ssize_t *contents_len)
 {
   struct process_file_node *file = hook;
   error_t err;
@@ -215,10 +204,7 @@ process_file_get_contents (void *hook, char **contents, size_t *contents_len)
   if ((proc_stat_flags (file->ps) & file->desc->needs) != file->desc->needs)
     return EIO;
 
-  *contents = file->desc->get_contents (file->ps, contents_len);
-  if (! *contents)
-    return ENOMEM;
-
+  *contents_len = file->desc->get_contents (file->ps, contents);
   return 0;
 }
 
diff --git a/procfs.c b/procfs.c
index a5f52b50..6d15e4fd 100644
--- a/procfs.c
+++ b/procfs.c
@@ -13,20 +13,20 @@ struct netnode
 
   /* (cached) contents of the node */
   char *contents;
-  size_t contents_len;
+  ssize_t contents_len;
 
   /* parent directory, if applicable */
   struct node *parent;
 };
 
 void
-procfs_cleanup_contents_with_free (void *hook, char *cont, size_t len)
+procfs_cleanup_contents_with_free (void *hook, char *cont, ssize_t len)
 {
   free (cont);
 }
 
 void
-procfs_cleanup_contents_with_vm_deallocate (void *hook, char *cont, size_t len)
+procfs_cleanup_contents_with_vm_deallocate (void *hook, char *cont, ssize_t len)
 {
   vm_deallocate (mach_task_self (), (vm_address_t) cont, (vm_size_t) len);
 }
@@ -109,7 +109,7 @@ procfs_make_ino (struct node *np, const char *filename)
   return (unsigned long) jrand48 (x);
 }
 
-error_t procfs_get_contents (struct node *np, char **data, size_t *data_len)
+error_t procfs_get_contents (struct node *np, char **data, ssize_t *data_len)
 {
   if (np->nn->ops->enable_refresh_hack_and_break_readdir && np->nn->contents)
     {
@@ -122,12 +122,15 @@ error_t procfs_get_contents (struct node *np, char **data, size_t *data_len)
   if (! np->nn->contents && np->nn->ops->get_contents)
     {
       char *contents;
-      size_t contents_len;
+      ssize_t contents_len;
       error_t err;
 
+      contents_len = -1;
       err = np->nn->ops->get_contents (np->nn->hook, &contents, &contents_len);
       if (err)
 	return err;
+      if (contents_len < 0)
+	return ENOMEM;
 
       np->nn->contents = contents;
       np->nn->contents_len = contents_len;
diff --git a/procfs.h b/procfs.h
index 8336ee85..e8ef18b3 100644
--- a/procfs.h
+++ b/procfs.h
@@ -16,9 +16,11 @@ struct procfs_node_ops
      symlink or directory, as determined by the file mode in
      netnode->nn_stat.  For regular files and symlinks, they are what
      you would expect; for directories, they are an argz vector of the
-     names of the entries.  */
-  error_t (*get_contents) (void *hook, char **contents, size_t *contents_len);
-  void (*cleanup_contents) (void *hook, char *contents, size_t contents_len);
+     names of the entries.  If upon return, *CONTENTS_LEN is negative or
+     unchanged, the call is considered to have failed because of a memory
+     allocation error.  */
+  error_t (*get_contents) (void *hook, char **contents, ssize_t *contents_len);
+  void (*cleanup_contents) (void *hook, char *contents, ssize_t contents_len);
 
   /* Lookup NAME in this directory, and store the result in *np.  The
      returned node should be created by lookup() using procfs_make_node() 
@@ -41,8 +43,8 @@ struct procfs_node_ops
 };
 
 /* These helper functions can be used as procfs_node_ops.cleanup_contents. */
-void procfs_cleanup_contents_with_free (void *, char *, size_t);
-void procfs_cleanup_contents_with_vm_deallocate (void *, char *, size_t);
+void procfs_cleanup_contents_with_free (void *, char *, ssize_t);
+void procfs_cleanup_contents_with_vm_deallocate (void *, char *, ssize_t);
 
 /* Create a new node and return it.  Returns NULL if it fails to allocate
    enough memory.  In this case, ops->cleanup will be invoked.  */
@@ -69,7 +71,7 @@ void procfs_node_chtype (struct node *np, mode_t type);
    corresponding child nodes.  */
 ino64_t procfs_make_ino (struct node *np, const char *filename);
 
-error_t procfs_get_contents (struct node *np, char **data, size_t *data_len);
+error_t procfs_get_contents (struct node *np, char **data, ssize_t *data_len);
 error_t procfs_lookup (struct node *np, const char *name, struct node **npp);
 void procfs_cleanup (struct node *np);
 
diff --git a/procfs_dir.c b/procfs_dir.c
index 4df46695..8ec3f7a5 100644
--- a/procfs_dir.c
+++ b/procfs_dir.c
@@ -11,7 +11,7 @@ struct procfs_dir_node
 };
 
 static error_t
-procfs_dir_get_contents (void *hook, char **contents, size_t *contents_len)
+procfs_dir_get_contents (void *hook, char **contents, ssize_t *contents_len)
 {
   static const char dot_dotdot[] = ".\0..";
   struct procfs_dir_node *dn = hook;
diff --git a/proclist.c b/proclist.c
index b5acb26c..38368feb 100644
--- a/proclist.c
+++ b/proclist.c
@@ -10,7 +10,7 @@
 #define PID_STR_SIZE (3 * sizeof (pid_t) + 1)
 
 static error_t
-proclist_get_contents (void *hook, char **contents, size_t *contents_len)
+proclist_get_contents (void *hook, char **contents, ssize_t *contents_len)
 {
   struct ps_context *pc = hook;
   pidarray_t pids;
diff --git a/rootdir.c b/rootdir.c
index cd8949bf..364b0731 100644
--- a/rootdir.c
+++ b/rootdir.c
@@ -44,7 +44,7 @@ get_boottime (struct ps_context *pc, struct timeval *tv)
 }
 
 static error_t
-rootdir_gc_version (void *hook, char **contents, size_t *contents_len)
+rootdir_gc_version (void *hook, char **contents, ssize_t *contents_len)
 {
   struct utsname uts;
   int r;
@@ -57,13 +57,13 @@ rootdir_gc_version (void *hook, char **contents, size_t *contents_len)
       "Linux version 2.6.1 (%s %s %s %s)\n",
       uts.sysname, uts.release, uts.version, uts.machine);
 
-  return *contents_len >= 0 ? 0 : ENOMEM;
+  return 0;
 }
 
 /* Uptime -- we use the start time of init to deduce it. This is probably a bit
    fragile, as any clock update will make the result inaccurate. */
 static error_t
-rootdir_gc_uptime (void *hook, char **contents, size_t *contents_len)
+rootdir_gc_uptime (void *hook, char **contents, ssize_t *contents_len)
 {
   struct timeval time, boottime;
   double up_secs;
@@ -87,11 +87,11 @@ rootdir_gc_uptime (void *hook, char **contents, size_t *contents_len)
      and there to make that work.  */
   *contents_len = asprintf (contents, "%.2lf %.2lf\n", up_secs, up_secs);
 
-  return *contents_len >= 0 ? 0 : ENOMEM;
+  return 0;
 }
 
 static error_t
-rootdir_gc_stat (void *hook, char **contents, size_t *contents_len)
+rootdir_gc_stat (void *hook, char **contents, ssize_t *contents_len)
 {
   struct timeval boottime, time;
   struct vm_statistics vmstats;
@@ -126,11 +126,11 @@ rootdir_gc_stat (void *hook, char **contents, size_t *contents_len)
       vmstats.pageins, vmstats.pageouts,
       boottime.tv_sec);
 
-  return *contents_len >= 0 ? 0 : ENOMEM;
+  return 0;
 }
 
 static error_t
-rootdir_gc_loadavg (void *hook, char **contents, size_t *contents_len)
+rootdir_gc_loadavg (void *hook, char **contents, ssize_t *contents_len)
 {
   host_load_info_data_t hli;
   mach_msg_type_number_t cnt;
@@ -148,11 +148,11 @@ rootdir_gc_loadavg (void *hook, char **contents, size_t *contents_len)
       hli.avenrun[1] / (double) LOAD_SCALE,
       hli.avenrun[2] / (double) LOAD_SCALE);
 
-  return *contents_len >= 0 ? 0 : ENOMEM;
+  return 0;
 }
 
 static error_t
-rootdir_gc_meminfo (void *hook, char **contents, size_t *contents_len)
+rootdir_gc_meminfo (void *hook, char **contents, ssize_t *contents_len)
 {
   host_basic_info_data_t hbi;
   mach_msg_type_number_t cnt;
@@ -183,11 +183,11 @@ rootdir_gc_meminfo (void *hook, char **contents, size_t *contents_len)
       (long unsigned) vmstats.inactive_count * PAGE_SIZE / 1024,
       (long unsigned) vmstats.wire_count * PAGE_SIZE / 1024);
 
-  return *contents_len >= 0 ? 0 : ENOMEM;
+  return 0;
 }
 
 static error_t
-rootdir_gc_vmstat (void *hook, char **contents, size_t *contents_len)
+rootdir_gc_vmstat (void *hook, char **contents, ssize_t *contents_len)
 {
   host_basic_info_data_t hbi;
   mach_msg_type_number_t cnt;
@@ -228,11 +228,11 @@ rootdir_gc_vmstat (void *hook, char **contents, size_t *contents_len)
       (long unsigned) vmstats.pageouts,
       (long unsigned) vmstats.faults);
 
-  return *contents_len >= 0 ? 0 : ENOMEM;
+  return 0;
 }
 
 static error_t
-rootdir_gc_cmdline (void *hook, char **contents, size_t *contents_len)
+rootdir_gc_cmdline (void *hook, char **contents, ssize_t *contents_len)
 {
   struct ps_context *pc = hook;
   struct proc_stat *ps;
@@ -267,10 +267,10 @@ out:
 }
 
 static error_t
-rootdir_gc_fakeself (void *hook, char **contents, size_t *contents_len)
+rootdir_gc_fakeself (void *hook, char **contents, ssize_t *contents_len)
 {
   *contents_len = asprintf (contents, "%d", opt_fake_self);
-  return *contents_len >= 0 ? 0 : ENOMEM;
+  return 0;
 }