Correct comparisons between size_t and ssize_t

* src/sfnt.c (sfnt_read_table_directory, sfnt_read_cmap_format_0)
(sfnt_read_cmap_format_2, sfnt_read_cmap_format_4)
(sfnt_read_cmap_format_6, sfnt_read_cmap_format_8)
(sfnt_read_cmap_format_12, sfnt_read_cmap_format_14)
(sfnt_read_cmap_table_1, sfnt_read_cmap_table)
(sfnt_read_head_table, sfnt_read_hhea_table, sfnt_read_maxp_table)
(sfnt_read_glyf_table, sfnt_read_hmtx_table, sfnt_read_name_table)
(sfnt_read_meta_table, sfnt_read_ttc_header)
(sfnt_read_default_uvs_table, sfnt_read_nondefault_uvs_table)
(sfnt_read_fvar_table, sfnt_read_gvar_table, sfnt_read_avar_table)
(sfnt_read_cvar_table, sfnt_read_OS_2_table):

* src/sfntfont.c (sfnt_enum_font): Revise code written with only
signed `long' in mind to properly compare size_t values with
ssize_t.

2 files changed, 62 insertions, 55 deletions

diff --git a/src/sfnt.c b/src/sfnt.c
index 9340d8abc66..360b0cd2d4d 100644
--- a/src/sfnt.c
+++ b/src/sfnt.c
@@ -202,9 +202,9 @@ sfnt_read_table_directory (int fd)
                        range_shift, uint16_t);
   rc = read (fd, subtable, offset);
 
-  if (rc < offset)
+  if (rc == -1 || rc < offset)
     {
-      if (rc >= sizeof (uint32_t))
+      if (rc != -1 && rc >= sizeof (uint32_t))
         {
           /* Detect a TTC file.  In that case, the first long will be
              ``ttcf''.  */
@@ -247,7 +247,7 @@ sfnt_read_table_directory (int fd)
 
   rc = read (fd, subtable->subtables, subtable_size);
 
-  if (rc < offset)
+  if (rc == -1 || rc < offset)
     {
       xfree (subtable);
       return NULL;
@@ -311,7 +311,7 @@ sfnt_read_cmap_format_0 (int fd,
                              language));
   rc = read (fd, &format0->language, wanted_size);
 
-  if (rc < wanted_size)
+  if (rc == -1 || rc < wanted_size)
     {
       xfree (format0);
       return (struct sfnt_cmap_format_0 *) -1;
@@ -349,7 +349,7 @@ sfnt_read_cmap_format_2 (int fd,
   /* Read the part before the variable length data.  */
   min_bytes -= offsetof (struct sfnt_cmap_format_2, language);
   rc = read (fd, &format2->language, min_bytes);
-  if (rc < min_bytes)
+  if (rc == -1 || rc < min_bytes)
     {
       xfree (format2);
       return (struct sfnt_cmap_format_2 *) -1;
@@ -383,7 +383,7 @@ sfnt_read_cmap_format_2 (int fd,
                - SFNT_ENDOF (struct sfnt_cmap_format_2,
                              sub_header_keys, uint16_t[256]));
   rc = read (fd, format2 + 1, min_bytes);
-  if (rc < min_bytes)
+  if (rc == -1 || rc < min_bytes)
     {
       xfree (format2);
       return (struct sfnt_cmap_format_2 *) -1;
@@ -454,7 +454,7 @@ sfnt_read_cmap_format_4 (int fd,
   /* Read the initial data.  */
   min_bytes -= offsetof (struct sfnt_cmap_format_4, language);
   rc = read (fd, &format4->language, min_bytes);
-  if (rc < min_bytes)
+  if (rc == -1 || rc < min_bytes)
     {
       xfree (format4);
       return (struct sfnt_cmap_format_4 *) -1;
@@ -490,7 +490,7 @@ sfnt_read_cmap_format_4 (int fd,
 
   /* Read the rest of the bytes to the end of format4.  */
   rc = read (fd, format4 + 1, bytes_minus_format4);
-  if (rc < bytes_minus_format4)
+  if (rc == -1 || rc < bytes_minus_format4)
     {
       xfree (format4);
       return (struct sfnt_cmap_format_4 *) -1;
@@ -559,7 +559,7 @@ sfnt_read_cmap_format_6 (int fd,
   /* Read the fixed size data.  */
   min_size -= offsetof (struct sfnt_cmap_format_6, language);
   rc = read (fd, &format6->language, min_size);
-  if (rc < min_size)
+  if (rc == -1 || rc < min_size)
     {
       xfree (format6);
       return (struct sfnt_cmap_format_6 *) -1;
@@ -583,7 +583,8 @@ sfnt_read_cmap_format_6 (int fd,
   rc = read (fd, format6 + 1,
              (format6->entry_count
               * sizeof *format6->glyph_index_array));
-  if (rc < format6->entry_count * sizeof *format6->glyph_index_array)
+  if (rc == -1 || (rc < (format6->entry_count
+                         * sizeof *format6->glyph_index_array)))
     {
       xfree (format6);
       return (struct sfnt_cmap_format_6 *) -1;
@@ -611,7 +612,7 @@ sfnt_read_cmap_format_8 (int fd,
   uint32_t length, i;
 
   /* Read the 32-bit length field.  */
-  if (read (fd, &length, sizeof (length)) < sizeof (length))
+  if (read (fd, &length, sizeof length) < (int) sizeof length)
     return (struct sfnt_cmap_format_8 *) -1;
 
   /* Swap the 32-bit length field.  */
@@ -633,7 +634,7 @@ sfnt_read_cmap_format_8 (int fd,
   /* Read the fixed length data.  */
   min_size -= offsetof (struct sfnt_cmap_format_8, language);
   rc = read (fd, &format8->language, min_size);
-  if (rc < min_size)
+  if (rc == -1 || rc < min_size)
     {
       xfree (format8);
       return (struct sfnt_cmap_format_8 *) -1;
@@ -669,7 +670,7 @@ sfnt_read_cmap_format_8 (int fd,
 
   /* Now read the variable length data.  */
   rc = read (fd, format8 + 1, temp);
-  if (rc < temp)
+  if (rc == -1 || rc < temp)
     {
       xfree (format8);
       return (struct sfnt_cmap_format_8 *) -1;
@@ -703,7 +704,7 @@ sfnt_read_cmap_format_12 (int fd,
   uint32_t length, i;
 
   /* Read the 32-bit length field.  */
-  if (read (fd, &length, sizeof (length)) < sizeof (length))
+  if (read (fd, &length, sizeof length) < (int) sizeof length)
     return (struct sfnt_cmap_format_12 *) -1;
 
   /* Swap the 32-bit length field.  */
@@ -725,7 +726,7 @@ sfnt_read_cmap_format_12 (int fd,
   /* Read the fixed length data.  */
   min_size -= offsetof (struct sfnt_cmap_format_12, language);
   rc = read (fd, &format12->language, min_size);
-  if (rc < min_size)
+  if (rc == -1 || rc < min_size)
     {
       xfree (format12);
       return (struct sfnt_cmap_format_12 *) -1;
@@ -761,7 +762,7 @@ sfnt_read_cmap_format_12 (int fd,
 
   /* Now read the variable length data.  */
   rc = read (fd, format12 + 1, temp);
-  if (rc < temp)
+  if (rc == -1 || rc < temp)
     {
       xfree (format12);
       return (struct sfnt_cmap_format_12 *) -1;
@@ -808,12 +809,12 @@ sfnt_read_cmap_format_14 (int fd,
   uint32_t buffer1[2];
   size_t size, temp;
   char buffer[3 + 4 + 4];
-  int i;
+  uint32_t i;
 
   /* Read the length field and number of variation selector
      records.  */
 
-  if (read (fd, buffer1, sizeof buffer1) < sizeof buffer1)
+  if (read (fd, buffer1, sizeof buffer1) < (int) sizeof buffer1)
     return NULL;
 
   length = buffer1[0];
@@ -847,7 +848,7 @@ sfnt_read_cmap_format_14 (int fd,
 
   for (i = 0; i < num_records; ++i)
     {
-      if (read (fd, buffer, sizeof buffer) < sizeof buffer)
+      if (read (fd, buffer, sizeof buffer) < (int) sizeof buffer)
         {
           xfree (format14);
           return NULL;
@@ -893,7 +894,7 @@ sfnt_read_cmap_table_1 (int fd, uint32_t directory_offset,
     return (struct sfnt_cmap_encoding_subtable_data *) -1;
 
   if (read (fd, &header.format, sizeof header.format)
-      < sizeof header.format)
+      < (int) sizeof header.format)
     return (struct sfnt_cmap_encoding_subtable_data *) -1;
 
   sfnt_swap16 (&header.format);
@@ -905,7 +906,7 @@ sfnt_read_cmap_table_1 (int fd, uint32_t directory_offset,
   if (header.format != 14)
     {
       if (read (fd, &header.length, sizeof header.length)
-          < sizeof header.length)
+          < (int) sizeof header.length)
         return (struct sfnt_cmap_encoding_subtable_data *) -1;
 
       sfnt_swap16 (&header.length);
@@ -984,7 +985,7 @@ sfnt_read_cmap_table (int fd, struct sfnt_offset_subtable *subtable,
   cmap = xmalloc (sizeof *cmap);
   rc = read (fd, cmap, sizeof *cmap);
 
-  if (rc < sizeof *cmap)
+  if (rc < (int) sizeof *cmap)
     {
       xfree (cmap);
       return NULL;
@@ -1011,7 +1012,7 @@ sfnt_read_cmap_table (int fd, struct sfnt_offset_subtable *subtable,
       /* Read the common part of the new subtable.  */
       rc = read (fd, &(*subtables)[i], sizeof (*subtables)[i]);
 
-      if (rc < sizeof (*subtables)[i])
+      if (rc < (int) sizeof (*subtables)[i])
         {
           xfree (cmap);
           xfree (*subtables);
@@ -1430,7 +1431,7 @@ sfnt_read_head_table (int fd, struct sfnt_offset_subtable *subtable)
   head = xmalloc (sizeof *head);
   rc = read (fd, head, sizeof *head);
 
-  if (rc < sizeof *head)
+  if (rc < (int) sizeof *head)
     {
       xfree (head);
       return NULL;
@@ -1506,7 +1507,7 @@ sfnt_read_hhea_table (int fd, struct sfnt_offset_subtable *subtable)
   hhea = xmalloc (sizeof *hhea);
   rc = read (fd, hhea, sizeof *hhea);
 
-  if (rc < sizeof *hhea)
+  if (rc < (int) sizeof *hhea)
     {
       xfree (hhea);
       return NULL;
@@ -1669,7 +1670,7 @@ sfnt_read_maxp_table (int fd, struct sfnt_offset_subtable *subtable)
   size = MIN (directory->length, sizeof *maxp);
   rc = read (fd, maxp, size);
 
-  if (rc < size)
+  if (rc == -1 || rc < size)
     {
       xfree (maxp);
       return NULL;
@@ -1749,7 +1750,7 @@ sfnt_read_glyf_table (int fd, struct sfnt_offset_subtable *subtable)
 
   /* Read the glyph data.  */
   rc = read (fd, glyf->glyphs, glyf->size);
-  if (rc < glyf->size)
+  if (rc == -1 || rc < glyf->size)
     {
       xfree (glyf);
       return NULL;
@@ -4637,7 +4638,7 @@ sfnt_read_hmtx_table (int fd, struct sfnt_offset_subtable *subtable,
 
   /* Read into hmtx + 1.  */
   rc = read (fd, hmtx + 1, size);
-  if (rc < size)
+  if (rc == -1 || rc < size)
     {
       xfree (hmtx);
       return NULL;
@@ -4801,7 +4802,7 @@ sfnt_read_name_table (int fd, struct sfnt_offset_subtable *subtable)
 
   /* Read the fixed length data.  */
   rc = read (fd, name, required);
-  if (rc < required)
+  if (rc == -1 || rc < required)
     {
       xfree (name);
       return NULL;
@@ -4835,8 +4836,8 @@ sfnt_read_name_table (int fd, struct sfnt_offset_subtable *subtable)
   rc = read (fd, name->name_records,
              (name->count
               * sizeof *name->name_records));
-  if (rc < (name->count
-            * sizeof *name->name_records))
+  if (rc == -1 || (rc < (name->count
+                         * sizeof *name->name_records)))
     {
       xfree (name);
       return NULL;
@@ -4892,7 +4893,7 @@ sfnt_read_name_table (int fd, struct sfnt_offset_subtable *subtable)
   name->data = (unsigned char *) (name->name_records
                                   + name->count);
   rc = read (fd, name->data, required);
-  if (rc < required)
+  if (rc == -1 || rc < required)
     {
       xfree (name);
       return NULL;
@@ -4974,7 +4975,7 @@ sfnt_read_meta_table (int fd, struct sfnt_offset_subtable *subtable)
 
   /* Read the header.  */
   rc = read (fd, meta, required);
-  if (rc < required)
+  if (rc == -1 || rc < required)
     {
       xfree (meta);
       return NULL;
@@ -5120,7 +5121,7 @@ sfnt_read_ttc_header (int fd)
   size = SFNT_ENDOF (struct sfnt_ttc_header, num_fonts,
                      uint32_t);
   rc = read (fd, ttc, size);
-  if (rc < size)
+  if (rc == -1 || rc < size)
     {
       xfree (ttc);
       return NULL;
@@ -5152,7 +5153,7 @@ sfnt_read_ttc_header (int fd)
   ttc = xrealloc (ttc, sizeof *ttc + size);
   ttc->offset_table = (uint32_t *) (ttc + 1);
   rc = read (fd, ttc->offset_table, size);
-  if (rc < size)
+  if (rc == -1 || rc < size)
     {
       xfree (ttc);
       return NULL;
@@ -5175,7 +5176,7 @@ sfnt_read_ttc_header (int fd)
                       uint32_t)
           - offsetof (struct sfnt_ttc_header, ul_dsig_tag));
   rc = read (fd, &ttc->ul_dsig_offset, size);
-  if (rc < size)
+  if (rc == -1 || rc < size)
     {
       xfree (ttc);
       return NULL;
@@ -12312,7 +12313,7 @@ sfnt_read_default_uvs_table (int fd, off_t offset)
 {
   struct sfnt_default_uvs_table *uvs;
   uint32_t num_ranges, i, j;
-  size_t size, temp;
+  ssize_t size, temp;
   char data[512];
 
   /* First, seek to the given offset.  */
@@ -12322,7 +12323,8 @@ sfnt_read_default_uvs_table (int fd, off_t offset)
 
   /* Next, read the number of ranges present.  */
 
-  if (read (fd, &num_ranges, sizeof num_ranges) != sizeof num_ranges)
+  if (read (fd, &num_ranges, sizeof num_ranges)
+      != (int) sizeof num_ranges)
     return NULL;
 
   /* Swap the number of ranges present.  */
@@ -12382,7 +12384,7 @@ sfnt_read_nondefault_uvs_table (int fd, off_t offset)
 {
   struct sfnt_nondefault_uvs_table *uvs;
   uint32_t num_mappings, i, j;
-  size_t size, temp;
+  ssize_t size, temp;
   char data[500];
 
   /* First, seek to the given offset.  */
@@ -12884,7 +12886,7 @@ sfnt_read_fvar_table (int fd, struct sfnt_offset_subtable *subtable)
   /* Read the fvar table header.  */
   buffer = NULL;
   rc = read (fd, fvar, min_bytes);
-  if (rc != min_bytes)
+  if (rc == -1 || rc != min_bytes)
     goto bail;
 
   /* Swap what was read.  */
@@ -12994,7 +12996,7 @@ sfnt_read_fvar_table (int fd, struct sfnt_offset_subtable *subtable)
     goto bail;
 
   rc = read (fd, fvar->axis, sizeof *fvar->axis * fvar->axis_count);
-  if (rc != sizeof *fvar->axis * fvar->axis_count)
+  if (rc == -1 || rc != sizeof *fvar->axis * fvar->axis_count)
     goto bail;
 
   /* Swap each axis.  */
@@ -13113,7 +13115,7 @@ sfnt_read_gvar_table (int fd, struct sfnt_offset_subtable *subtable)
 
   /* Read the gvar table header.  */
   rc = read (fd, gvar, min_bytes);
-  if (rc != min_bytes)
+  if (rc == -1 || rc != min_bytes)
     goto bail;
 
   /* Swap what was read.  */
@@ -13179,7 +13181,7 @@ sfnt_read_gvar_table (int fd, struct sfnt_offset_subtable *subtable)
     {
       gvar->u.offset_long = (uint32_t *) (gvar + 1);
       rc = read (fd, gvar->u.offset_long, off_size);
-      if (rc != off_size)
+      if (rc == -1 || rc != off_size)
         goto bail;
 
       for (i = 0; i <= gvar->glyph_count; ++i)
@@ -13200,8 +13202,9 @@ sfnt_read_gvar_table (int fd, struct sfnt_offset_subtable *subtable)
       if (lseek (fd, offset, SEEK_SET) != offset)
         goto bail;
 
-      if (read (fd, gvar->global_coords, coordinate_size)
-          != coordinate_size)
+      rc = read (fd, gvar->global_coords, coordinate_size);
+
+      if (rc == -1 || rc != coordinate_size)
         goto bail;
 
       for (i = 0; i < coordinate_size / sizeof *gvar->global_coords; ++i)
@@ -13224,8 +13227,9 @@ sfnt_read_gvar_table (int fd, struct sfnt_offset_subtable *subtable)
       if (lseek (fd, offset, SEEK_SET) != offset)
         goto bail;
 
-      if (read (fd, gvar->glyph_variation_data,
-                gvar->data_size) != gvar->data_size)
+      rc = read (fd, gvar->glyph_variation_data, gvar->data_size);
+
+      if (rc == -1 || rc != gvar->data_size)
         goto bail;
     }
 
@@ -13276,7 +13280,7 @@ sfnt_read_avar_table (int fd, struct sfnt_offset_subtable *subtable)
 
   /* Read the avar table header.  */
   rc = read (fd, avar, min_size);
-  if (rc != min_size)
+  if (rc == -1 || rc != min_size)
     goto bail;
 
   /* Swap what was read.  */
@@ -13293,7 +13297,7 @@ sfnt_read_avar_table (int fd, struct sfnt_offset_subtable *subtable)
   size = directory->length - min_size;
   buffer = xmalloc (size);
   rc = read (fd, buffer, size);
-  if (rc != size)
+  if (rc == -1 || rc != size)
     goto bail1;
 
   /* Swap each word.  */
@@ -13594,7 +13598,7 @@ sfnt_read_cvar_table (int fd, struct sfnt_offset_subtable *subtable,
   size = directory->length - min_size;
   buffer = xmalloc (size);
   rc = read (fd, buffer, size);
-  if (rc != size)
+  if (rc == -1 || rc != size)
     goto bail;
 
   /* Now figure out how large cvar must be by reading the tuples.  */
@@ -15346,7 +15350,7 @@ sfnt_read_OS_2_table (int fd, struct sfnt_offset_subtable *subtable)
                        unsigned char[10]);
   rc = read (fd, OS_2, wanted);
 
-  if (rc != wanted)
+  if (rc == -1 || rc != wanted)
     {
       xfree (OS_2);
       return NULL;
@@ -15377,7 +15381,7 @@ sfnt_read_OS_2_table (int fd, struct sfnt_offset_subtable *subtable)
             - offsetof (struct sfnt_OS_2_table, ul_unicode_range));
   rc = read (fd, &OS_2->ul_unicode_range, wanted);
 
-  if (rc != wanted)
+  if (rc == -1 || rc != wanted)
     {
       xfree (OS_2);
       return NULL;
diff --git a/src/sfntfont.c b/src/sfntfont.c
index db527d7d4af..d556092db12 100644
--- a/src/sfntfont.c
+++ b/src/sfntfont.c
@@ -1144,7 +1144,9 @@ sfnt_enum_font_1 (int fd, const char *file,
 int
 sfnt_enum_font (const char *file)
 {
-  int fd, rc;
+  int fd;
+  int rc;
+  off_t seek;
   struct sfnt_offset_subtable *subtables;
   struct sfnt_ttc_header *ttc;
   size_t i;
@@ -1175,8 +1177,9 @@ sfnt_enum_font (const char *file)
 
       for (i = 0; i < ttc->num_fonts; ++i)
         {
-          if (lseek (fd, ttc->offset_table[i], SEEK_SET)
-              != ttc->offset_table[i])
+          seek = lseek (fd, ttc->offset_table[i], SEEK_SET);
+
+          if (seek == -1 || seek != ttc->offset_table[i])
             continue;
 
           subtables = sfnt_read_table_directory (fd);