The Tor Browser: security/nss/lib/base/error.c@b8a032363ba2 (annotated)

security/nss/lib/base/error.c@b8a032363ba2 (annotated)

security/nss/lib/base/error.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /*
  * error.c
  *
  * This file contains the code implementing the per-thread error
  * stacks upon which most NSS routines report their errors.
  */
 #ifndef BASE_H
 #include "base.h"
 #endif /* BASE_H */
 #include <limits.h> /* for UINT_MAX */
 #include <string.h> /* for memmove */
 #define NSS_MAX_ERROR_STACK_COUNT 16 /* error codes */
 /*
  * The stack itself has a header, and a sequence of integers.
  * The header records the amount of space (as measured in stack
  * slots) already allocated for the stack, and the count of the
  * number of records currently being used.
  */
 struct stack_header_str {
   PRUint16 space;
   PRUint16 count;
 };
 struct error_stack_str {
   struct stack_header_str header;
   PRInt32 stack[1];
 };
 typedef struct error_stack_str error_stack;
 /*
  * error_stack_index
  *
  * Thread-private data must be indexed.  This is that index.
  * See PR_NewThreadPrivateIndex for more information.
  *
  * Thread-private data indexes are in the range [0, 127].
  */
 #define INVALID_TPD_INDEX UINT_MAX
 static PRUintn error_stack_index = INVALID_TPD_INDEX;
 /*
  * call_once
  *
  * The thread-private index must be obtained (once!) at runtime.
  * This block is used for that one-time call.
  */
 static PRCallOnceType error_call_once;
 /*
  * error_once_function
  *
  * This is the once-called callback.
  */
 static PRStatus
 error_once_function ( void)
 {
   return PR_NewThreadPrivateIndex(&error_stack_index, PR_Free);
 }
 /*
  * error_get_my_stack
  *
  * This routine returns the calling thread's error stack, creating
  * it if necessary.  It may return NULL upon error, which implicitly
  * means that it ran out of memory.
  */
 static error_stack *
 error_get_my_stack ( void)
 {
   PRStatus st;
   error_stack *rv;
   PRUintn new_size;
   PRUint32 new_bytes;
   error_stack *new_stack;
   if( INVALID_TPD_INDEX == error_stack_index ) {
     st = PR_CallOnce(&error_call_once, error_once_function);
     if( PR_SUCCESS != st ) {
       return (error_stack *)NULL;
     }
   }
   rv = (error_stack *)PR_GetThreadPrivate(error_stack_index);
   if( (error_stack *)NULL == rv ) {
     /* Doesn't exist; create one */
     new_size = 16;
   } else if( rv->header.count == rv->header.space  &&
              rv->header.count  < NSS_MAX_ERROR_STACK_COUNT ) {
     /* Too small, expand it */
     new_size = PR_MIN( rv->header.space * 2, NSS_MAX_ERROR_STACK_COUNT);
   } else {
     /* Okay, return it */
     return rv;
   }
   new_bytes = (new_size * sizeof(PRInt32)) + sizeof(error_stack);
   /* Use NSPR's calloc/realloc, not NSS's, to avoid loops! */
   new_stack = PR_Calloc(1, new_bytes);
   if( (error_stack *)NULL != new_stack ) {
     if( (error_stack *)NULL != rv ) {
 	(void)nsslibc_memcpy(new_stack,rv,rv->header.space);
     }
     new_stack->header.space = new_size;
   }
   /* Set the value, whether or not the allocation worked */
   PR_SetThreadPrivate(error_stack_index, new_stack);
   return new_stack;
 }
 /*
  * The error stack
  *
  * The public methods relating to the error stack are:
  *
  *  NSS_GetError
  *  NSS_GetErrorStack
  *
  * The nonpublic methods relating to the error stack are:
  *
  *  nss_SetError
  *  nss_ClearErrorStack
  *
  */
 /*
  * NSS_GetError
  *
  * This routine returns the highest-level (most general) error set
  * by the most recent NSS library routine called by the same thread
  * calling this routine.
  *
  * This routine cannot fail.  However, it may return zero, which
  * indicates that the previous NSS library call did not set an error.
  *
  * Return value:
  *  0 if no error has been set
  *  A nonzero error number
  */
 NSS_IMPLEMENT PRInt32
 NSS_GetError ( void)
 {
   error_stack *es = error_get_my_stack();
   if( (error_stack *)NULL == es ) {
     return NSS_ERROR_NO_MEMORY; /* Good guess! */
   }
   if( 0 == es->header.count ) {
     return 0;
   }
   return es->stack[ es->header.count-1 ];
 }
 /*
  * NSS_GetErrorStack
  *
  * This routine returns a pointer to an array of integers, containing
  * the entire sequence or "stack" of errors set by the most recent NSS
  * library routine called by the same thread calling this routine.
  * NOTE: the caller DOES NOT OWN the memory pointed to by the return
  * value.  The pointer will remain valid until the calling thread
  * calls another NSS routine.  The lowest-level (most specific) error
  * is first in the array, and the highest-level is last.  The array is
  * zero-terminated.  This routine may return NULL upon error; this
  * indicates a low-memory situation.
  *
  * Return value:
  *  NULL upon error, which is an implied NSS_ERROR_NO_MEMORY
  *  A NON-caller-owned pointer to an array of integers
  */
 NSS_IMPLEMENT PRInt32 *
 NSS_GetErrorStack ( void)
 {
   error_stack *es = error_get_my_stack();
   if( (error_stack *)NULL == es ) {
     return (PRInt32 *)NULL;
   }
   /* Make sure it's terminated */
   es->stack[ es->header.count ] = 0;
   return es->stack;
 }
 /*
  * nss_SetError
  *
  * This routine places a new error code on the top of the calling
  * thread's error stack.  Calling this routine wiht an error code
  * of zero will clear the error stack.
  */
 NSS_IMPLEMENT void
 nss_SetError ( PRUint32 error)
 {
   error_stack *es;
   if( 0 == error ) {
     nss_ClearErrorStack();
     return;
   }
   es = error_get_my_stack();
   if( (error_stack *)NULL == es ) {
     /* Oh, well. */
     return;
   }
   if (es->header.count < es->header.space) {
     es->stack[ es->header.count++ ] = error;
   } else {
     memmove(es->stack, es->stack + 1,
 		(es->header.space - 1) * (sizeof es->stack[0]));
     es->stack[ es->header.space - 1 ] = error;
   }
   return;
 }
 /*
  * nss_ClearErrorStack
  *
  * This routine clears the calling thread's error stack.
  */
 NSS_IMPLEMENT void
 nss_ClearErrorStack ( void)
 {
   error_stack *es = error_get_my_stack();
   if( (error_stack *)NULL == es ) {
     /* Oh, well. */
     return;
   }
   es->header.count = 0;
   es->stack[0] = 0;
   return;
 }
 /*
  * nss_DestroyErrorStack
  *
  * This routine frees the calling thread's error stack.
  */
 NSS_IMPLEMENT void
 nss_DestroyErrorStack ( void)
 {
   if( INVALID_TPD_INDEX != error_stack_index ) {
     PR_SetThreadPrivate(error_stack_index, NULL);
   }
   return;
 }

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security/nss/lib/base/error.c@b8a032363ba2 (annotated)

security/nss/lib/base/error.c