Re: [RFC PATCH spice-server] replay: Use setjmp/longjmp for error handling

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Hi

----- Original Message -----
> To avoid checking for error in all the path use setjmp/longjmp.
> This allow to jump directly to the error handling code in
> spice_replay_next_cmd.
> 
> Signed-off-by: Frediano Ziglio <fziglio@xxxxxxxxxx>
> ---
>  server/red-replay-qxl.c | 142
>  ++++++++++++------------------------------------
>  1 file changed, 35 insertions(+), 107 deletions(-)
> 
> I'm not a great fun of setjmp/longjmp but I have to say
> this way simplify different checks.
> 

/me neither

cheers

> diff --git a/server/red-replay-qxl.c b/server/red-replay-qxl.c
> index 78de48b..daaca0d 100644
> --- a/server/red-replay-qxl.c
> +++ b/server/red-replay-qxl.c
> @@ -23,13 +23,16 @@
>  #include <inttypes.h>
>  #include <zlib.h>
>  #include <pthread.h>
> +#include <glib.h>
> +#include <assert.h>
> +#include <setjmp.h>
> +
>  #include "reds.h"
>  #include "red-qxl.h"
>  #include "red-common.h"
>  #include "memslot.h"
>  #include "red-parse-qxl.h"
>  #include "red-replay-qxl.h"
> -#include <glib.h>
>  
>  #define QXLPHYSICAL_FROM_PTR(ptr) ((QXLPHYSICAL)(intptr_t)(ptr))
>  #define QXLPHYSICAL_TO_PTR(phy) ((void*)(intptr_t)(phy))
> @@ -42,6 +45,7 @@ typedef enum {
>  struct SpiceReplay {
>      FILE *fd;
>      gboolean error;
> +    jmp_buf jmp_error;
>      int counter;
>      bool created_primary;
>  
> @@ -57,18 +61,24 @@ struct SpiceReplay {
>      pthread_cond_t cond;
>  };
>  
> +static void SPICE_GNUC_NORETURN replay_got_error(SpiceReplay *replay)
> +{
> +    replay->error = TRUE;
> +    longjmp(replay->jmp_error, 1);
> +}
> +
>  static ssize_t replay_fread(SpiceReplay *replay, uint8_t *buf, size_t size)
>  {
>      if (replay->error || feof(replay->fd) ||
>          fread(buf, 1, size, replay->fd) != size) {
> -        replay->error = TRUE;
> +        replay_got_error(replay);
>          return 0;
>      }
>      return size;
>  }
>  
>  __attribute__((format(scanf, 2, 3)))
> -static replay_t replay_fscanf_check(SpiceReplay *replay, const char *fmt,
> ...)
> +static void replay_fscanf_check(SpiceReplay *replay, const char *fmt, ...)
>  {
>      va_list ap;
>      int ret;
> @@ -76,19 +86,17 @@ static replay_t replay_fscanf_check(SpiceReplay *replay,
> const char *fmt, ...)
>      replay->end_pos = -1;
>  
>      if (replay->error) {
> -        return REPLAY_ERROR;
> +        replay_got_error(replay);
>      }
>      if (feof(replay->fd)) {
> -        replay->error = TRUE;
> -        return REPLAY_ERROR;
> +        replay_got_error(replay);
>      }
>      va_start(ap, fmt);
>      ret = vfscanf(replay->fd, fmt, ap);
>      va_end(ap);
>      if (ret == EOF || replay->end_pos < 0) {
> -        replay->error = TRUE;
> +        replay_got_error(replay);
>      }
> -    return replay->error ? REPLAY_ERROR : REPLAY_OK;
>  }
>  #define replay_fscanf(r, fmt, ...) \
>      replay_fscanf_check(r, fmt "%n", ## __VA_ARGS__, &r->end_pos)
> @@ -217,8 +225,8 @@ static void hexdump(uint8_t *hex, uint8_t bytes)
>  }
>  #endif
>  
> -static replay_t read_binary(SpiceReplay *replay, const char *prefix, size_t
> *size, uint8_t
> -                            **buf, size_t base_size)
> +static void read_binary(SpiceReplay *replay, const char *prefix, size_t
> *size,
> +                        uint8_t **buf, size_t base_size)
>  {
>      char template[1024];
>      int with_zlib = -1;
> @@ -228,9 +236,6 @@ static replay_t read_binary(SpiceReplay *replay, const
> char *prefix, size_t *siz
>  
>      snprintf(template, sizeof(template), "binary %%d %s %%ld:%%n", prefix);
>      replay_fscanf_check(replay, template, &with_zlib, size,
>      &replay->end_pos);
> -    if (replay->error) {
> -        return REPLAY_ERROR;
> -    }
>  
>      if (*buf == NULL) {
>          *buf = replay_malloc(replay, *size + base_size);
> @@ -246,13 +251,8 @@ static replay_t read_binary(SpiceReplay *replay, const
> char *prefix, size_t *siz
>          int ret;
>  
>          replay_fscanf(replay, "%u:", &zlib_size);
> -        if (replay->error) {
> -            return REPLAY_ERROR;
> -        }
>          zlib_buffer = replay_malloc(replay, zlib_size);
> -        if (replay_fread(replay, zlib_buffer, zlib_size) != zlib_size) {
> -            return REPLAY_ERROR;
> -        }
> +        replay_fread(replay, zlib_buffer, zlib_size);
>          strm.zalloc = Z_NULL;
>          strm.zfree = Z_NULL;
>          strm.opaque = Z_NULL;
> @@ -272,7 +272,7 @@ static replay_t read_binary(SpiceReplay *replay, const
> char *prefix, size_t *siz
>                   * it seems it may kill the red_worker thread (so a chunk is
>                   * left hanging and the rest of the message is never
>                   written).
>                   * Let it pass */
> -                return REPLAY_ERROR;
> +                replay_got_error(replay);
>              }
>              if (ret != Z_OK) {
>                  spice_warn_if_reached();
> @@ -284,7 +284,7 @@ static replay_t read_binary(SpiceReplay *replay, const
> char *prefix, size_t *siz
>          replay_fread(replay, *buf + base_size, *size);
>      }
>  #endif
> -    return replay_fscanf(replay, "\n");
> +    replay_fscanf(replay, "\n");
>  }
>  
>  static ssize_t red_replay_data_chunks(SpiceReplay *replay, const char
>  *prefix,
> @@ -296,25 +296,19 @@ static ssize_t red_replay_data_chunks(SpiceReplay
> *replay, const char *prefix,
>      QXLDataChunk *cur, *next;
>  
>      replay_fscanf(replay, "data_chunks %u %zu\n", &count_chunks,
>      &data_size);
> -    if (replay->error) {
> -        return -1;
> -    }
>      if (base_size == 0) {
>          base_size = sizeof(QXLDataChunk);
>      }
>  
> -    if (read_binary(replay, prefix, &next_data_size, mem, base_size) ==
> REPLAY_ERROR) {
> -        return -1;
> -    }
> +    read_binary(replay, prefix, &next_data_size, mem, base_size);
> +
>      cur = (QXLDataChunk*)(*mem + base_size - sizeof(QXLDataChunk));
>      cur->data_size = next_data_size;
>      data_size = cur->data_size;
>      cur->next_chunk = cur->prev_chunk = 0;
>      while (count_chunks-- > 0) {
> -        if (read_binary(replay, prefix, &next_data_size,
> (uint8_t**)&cur->next_chunk,
> -            sizeof(QXLDataChunk)) == REPLAY_ERROR) {
> -            return -1;
> -        }
> +        read_binary(replay, prefix, &next_data_size,
> (uint8_t**)&cur->next_chunk,
> +                    sizeof(QXLDataChunk));
>          data_size += next_data_size;
>          next = QXLPHYSICAL_TO_PTR(cur->next_chunk);
>          next->prev_chunk = QXLPHYSICAL_FROM_PTR(cur);
> @@ -389,9 +383,6 @@ static QXLClipRects *red_replay_clip_rects(SpiceReplay
> *replay)
>      unsigned int num_rects;
>  
>      replay_fscanf(replay, "num_rects %u\n", &num_rects);
> -    if (replay->error) {
> -        return NULL;
> -    }
>      if (red_replay_data_chunks(replay, "clip_rects", (uint8_t**)&qxl,
>      sizeof(QXLClipRects)) < 0) {
>          return NULL;
>      }
> @@ -423,9 +414,6 @@ static QXLImage *red_replay_image(SpiceReplay *replay,
> uint32_t flags)
>      int has_image;
>  
>      replay_fscanf(replay, "image %d\n", &has_image);
> -    if (replay->error) {
> -        return NULL;
> -    }
>      if (!has_image) {
>          return NULL;
>      }
> @@ -436,9 +424,6 @@ static QXLImage *red_replay_image(SpiceReplay *replay,
> uint32_t flags)
>      replay_fscanf(replay, "descriptor.flags %d\n", &temp);
>      qxl->descriptor.flags = temp;
>      replay_fscanf(replay, "descriptor.width %d\n", &qxl->descriptor.width);
>      replay_fscanf(replay, "descriptor.height %d\n",
>      &qxl->descriptor.height);
> -    if (replay->error) {
> -        return NULL;
> -    }
>  
>      switch (qxl->descriptor.type) {
>      case SPICE_IMAGE_TYPE_BITMAP:
> @@ -454,9 +439,6 @@ static QXLImage *red_replay_image(SpiceReplay *replay,
> uint32_t flags)
>              unsigned int i, num_ents;
>  
>              replay_fscanf(replay, "qp.num_ents %u\n", &num_ents);
> -            if (replay->error) {
> -                return NULL;
> -            }
>              qp = replay_malloc(replay, sizeof(QXLPalette) + num_ents *
>              sizeof(qp->ents[0]));
>              qp->num_ents = num_ents;
>              qxl->bitmap.palette = QXLPHYSICAL_FROM_PTR(qp);
> @@ -481,18 +463,12 @@ static QXLImage *red_replay_image(SpiceReplay *replay,
> uint32_t flags)
>          break;
>      case SPICE_IMAGE_TYPE_SURFACE:
>          replay_fscanf(replay, "surface_image.surface_id %d\n",
>          &qxl->surface_image.surface_id);
> -        if (replay->error) {
> -            return NULL;
> -        }
>          qxl->surface_image.surface_id = replay_id_get(replay,
>          qxl->surface_image.surface_id);
>          break;
>      case SPICE_IMAGE_TYPE_QUIC:
>          // TODO - make this much nicer (precompute size and allocs, store
>          them during
>          // record, then reread into them. and use MPEG-4).
>          replay_fscanf(replay, "quic.data_size %d\n", &qxl->quic.data_size);
> -        if (replay->error) {
> -            return NULL;
> -        }
>          qxl = replay_realloc(replay, qxl, sizeof(QXLImageDescriptor) +
>          sizeof(QXLQUICData) +
>                               qxl->quic.data_size);
>          size = red_replay_data_chunks(replay, "quic.data",
>          (uint8_t**)&qxl->quic.data, 0);
> @@ -534,9 +510,6 @@ static void red_replay_image_free(SpiceReplay *replay,
> QXLPHYSICAL p, uint32_t f
>  static void red_replay_brush_ptr(SpiceReplay *replay, QXLBrush *qxl,
>  uint32_t flags)
>  {
>      replay_fscanf(replay, "type %d\n", &qxl->type);
> -    if (replay->error) {
> -        return;
> -    }
>  
>      switch (qxl->type) {
>      case SPICE_BRUSH_TYPE_SOLID:
> @@ -702,9 +675,6 @@ static void red_replay_stroke_ptr(SpiceReplay *replay,
> QXLStroke *qxl, uint32_t
>  
>      qxl->path = QXLPHYSICAL_FROM_PTR(red_replay_path(replay));
>      replay_fscanf(replay, "attr.flags %d\n", &temp); qxl->attr.flags = temp;
> -    if (replay->error) {
> -        return;
> -    }
>      if (qxl->attr.flags & SPICE_LINE_FLAGS_STYLED) {
>          size_t size;
>  
> @@ -805,9 +775,6 @@ static void red_replay_invers_free(SpiceReplay *replay,
> QXLInvers *qxl, uint32_t
>  static void red_replay_clip_ptr(SpiceReplay *replay, QXLClip *qxl)
>  {
>      replay_fscanf(replay, "type %d\n", &qxl->type);
> -    if (replay->error) {
> -        return;
> -    }
>      switch (qxl->type) {
>      case SPICE_CLIP_TYPE_RECTS:
>          qxl->data = QXLPHYSICAL_FROM_PTR(red_replay_clip_rects(replay));
> @@ -877,24 +844,15 @@ static QXLDrawable
> *red_replay_native_drawable(SpiceReplay *replay, uint32_t fla
>      replay_fscanf(replay, "self_bitmap %d\n", &temp); qxl->self_bitmap =
>      temp;
>      red_replay_rect_ptr(replay, "self_bitmap_area", &qxl->self_bitmap_area);
>      replay_fscanf(replay, "surface_id %d\n", &qxl->surface_id);
> -    if (replay->error) {
> -        return NULL;
> -    }
>      qxl->surface_id = replay_id_get(replay, qxl->surface_id);
>  
>      for (i = 0; i < 3; i++) {
>          replay_fscanf(replay, "surfaces_dest %d\n", &qxl->surfaces_dest[i]);
> -        if (replay->error) {
> -            return NULL;
> -        }
>          qxl->surfaces_dest[i] = replay_id_get(replay,
>          qxl->surfaces_dest[i]);
>          red_replay_rect_ptr(replay, "surfaces_rects",
>          &qxl->surfaces_rects[i]);
>      }
>  
>      replay_fscanf(replay, "type %d\n", &temp); qxl->type = temp;
> -    if (replay->error) {
> -        return NULL;
> -    }
>      switch (qxl->type) {
>      case QXL_DRAW_ALPHA_BLEND:
>          red_replay_alpha_blend_ptr(replay, &qxl->u.alpha_blend, flags);
> @@ -1017,9 +975,6 @@ static QXLCompatDrawable
> *red_replay_compat_drawable(SpiceReplay *replay, uint32
>      red_replay_rect_ptr(replay, "bitmap_area", &qxl->bitmap_area);
>  
>      replay_fscanf(replay, "type %d\n", &temp); qxl->type = temp;
> -    if (replay->error) {
> -        return NULL;
> -    }
>      switch (qxl->type) {
>      case QXL_DRAW_ALPHA_BLEND:
>          red_replay_alpha_blend_ptr_compat(replay, &qxl->u.alpha_blend,
>          flags);
> @@ -1072,9 +1027,6 @@ static QXLCompatDrawable
> *red_replay_compat_drawable(SpiceReplay *replay, uint32
>  static QXLPHYSICAL red_replay_drawable(SpiceReplay *replay, uint32_t flags)
>  {
>      replay_fscanf(replay, "drawable\n");
> -    if (replay->error) {
> -        return 0;
> -    }
>      if (flags & QXL_COMMAND_FLAG_COMPAT) {
>          return QXLPHYSICAL_FROM_PTR(red_replay_compat_drawable(replay,
>          flags));
>      } else {
> @@ -1090,9 +1042,6 @@ static QXLUpdateCmd *red_replay_update_cmd(SpiceReplay
> *replay)
>      red_replay_rect_ptr(replay, "area", &qxl->area);
>      replay_fscanf(replay, "update_id %d\n", &qxl->update_id);
>      replay_fscanf(replay, "surface_id %d\n", &qxl->surface_id);
> -    if (replay->error) {
> -        return NULL;
> -    }
>      qxl->surface_id = replay_id_get(replay, qxl->surface_id);
>  
>      return qxl;
> @@ -1118,9 +1067,6 @@ static QXLSurfaceCmd
> *red_replay_surface_cmd(SpiceReplay *replay)
>      replay_fscanf(replay, "surface_id %d\n", &qxl->surface_id);
>      replay_fscanf(replay, "type %d\n", &temp); qxl->type = temp;
>      replay_fscanf(replay, "flags %d\n", &qxl->flags);
> -    if (replay->error) {
> -        return NULL;
> -    }
>  
>      switch (qxl->type) {
>      case QXL_SURFACE_CMD_CREATE:
> @@ -1128,9 +1074,6 @@ static QXLSurfaceCmd
> *red_replay_surface_cmd(SpiceReplay *replay)
>          replay_fscanf(replay, "u.surface_create.width %d\n",
>          &qxl->u.surface_create.width);
>          replay_fscanf(replay, "u.surface_create.height %d\n",
>          &qxl->u.surface_create.height);
>          replay_fscanf(replay, "u.surface_create.stride %d\n",
>          &qxl->u.surface_create.stride);
> -        if (replay->error) {
> -            return NULL;
> -        }
>          size = qxl->u.surface_create.height *
>          abs(qxl->u.surface_create.stride);
>          if ((qxl->flags & QXL_SURF_FLAG_KEEP_DATA) != 0) {
>              read_binary(replay, "data", &read_size,
>              (uint8_t**)&qxl->u.surface_create.data, 0);
> @@ -1178,9 +1121,6 @@ static QXLCursor *red_replay_cursor(SpiceReplay
> *replay)
>      cursor.header.hot_spot_y = temp;
>  
>      replay_fscanf(replay, "data_size %d\n", &temp);
> -    if (replay->error) {
> -        return NULL;
> -    }
>      data_size = red_replay_data_chunks(replay, "cursor", (uint8_t**)&qxl,
>      sizeof(QXLCursor));
>      if (data_size < 0) {
>          return NULL;
> @@ -1197,9 +1137,6 @@ static QXLCursorCmd *red_replay_cursor_cmd(SpiceReplay
> *replay)
>  
>      replay_fscanf(replay, "cursor_cmd\n");
>      replay_fscanf(replay, "type %d\n", &temp);
> -    if (replay->error) {
> -        return NULL;
> -    }
>      qxl->type = temp;
>      switch (qxl->type) {
>      case QXL_CURSOR_SET:
> @@ -1249,9 +1186,6 @@ static void replay_handle_create_primary(QXLWorker
> *worker, SpiceReplay *replay)
>          &surface.stride, &surface.format);
>      replay_fscanf(replay, "%d %d %d %d\n", &surface.position,
>      &surface.mouse_mode,
>          &surface.flags, &surface.type);
> -    if (replay->error) {
> -        return;
> -    }
>      read_binary(replay, "data", &size, &mem, 0);
>      surface.group_id = 0;
>      surface.mem = QXLPHYSICAL_FROM_PTR(mem);
> @@ -1302,12 +1236,19 @@ SPICE_GNUC_VISIBLE QXLCommandExt*
> spice_replay_next_cmd(SpiceReplay *replay,
>      int what = -1;
>      int counter;
>  
> +    if (setjmp(replay->jmp_error)) {
> +        /* if there were some allocation during the read free all
> +         * buffers allocated to avoid leaks */
> +        if (replay->allocated) {
> +            g_list_free_full(replay->allocated, free);
> +            replay->allocated = NULL;
> +        }
> +        return NULL;
> +    }
> +
>      while (what != 0) {
>          replay_fscanf(replay, "event %d %d %d %"SCNu64"\n", &counter,
>                              &what, &type, &timestamp);
> -        if (replay->error) {
> -            goto error;
> -        }
>          if (what == 1) {
>              replay_handle_dev_input(worker, replay, type);
>          }
> @@ -1335,10 +1276,6 @@ SPICE_GNUC_VISIBLE QXLCommandExt*
> spice_replay_next_cmd(SpiceReplay *replay,
>          break;
>      }
>  
> -    if (replay->error) {
> -        goto error;
> -    }
> -
>      QXLReleaseInfo *info;
>      switch (cmd->cmd.type) {
>      case QXL_CMD_DRAW:
> @@ -1359,15 +1296,6 @@ SPICE_GNUC_VISIBLE QXLCommandExt*
> spice_replay_next_cmd(SpiceReplay *replay,
>      replay->counter++;
>  
>      return cmd;
> -
> -error:
> -    /* if there were some allocation during the read free all
> -     * buffers allocated to avoid leaks */
> -    if (replay->allocated) {
> -        g_list_free_full(replay->allocated, free);
> -        replay->allocated = NULL;
> -    }
> -    return NULL;
>  }
>  
>  SPICE_GNUC_VISIBLE void spice_replay_free_cmd(SpiceReplay *replay,
>  QXLCommandExt *cmd)
> --
> 2.7.4
> 
> _______________________________________________
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> Spice-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/spice-devel
> 
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