diff --git a/fofi/FoFiBase.cc b/fofi/FoFiBase.cc
index ef8992a..52ed27d 100644
--- a/fofi/FoFiBase.cc
+++ b/fofi/FoFiBase.cc
@@ -14,6 +14,7 @@
 
 #include <stdio.h>
 #include "goo/gmem.h"
+#include "Error.h"
 #include "FoFiBase.h"
 
 //------------------------------------------------------------------------
@@ -38,11 +39,18 @@ char *FoFiBase::readFile(char *fileName, int *fileLen) {
   int n;
 
   if (!(f = fopen(fileName, "rb"))) {
+    error(-1, "Cannot open '%s'", fileName);
+    return NULL;
+  }
+  if (fseek(f, 0, SEEK_END) != 0) {
+    error(-1, "Cannot seek to end of file");
     return NULL;
   }
-  fseek(f, 0, SEEK_END);
   n = (int)ftell(f);
-  fseek(f, 0, SEEK_SET);
+  if (fseek(f, 0, SEEK_SET) != 0) {
+    error(-1, "Cannot seek to start of file");
+    return NULL;
+  }
   buf = (char *)gmalloc(n);
   if ((int)fread(buf, 1, n, f) != n) {
     gfree(buf);
diff --git a/poppler/GfxFont.cc b/poppler/GfxFont.cc
index 655e259..eeff005 100644
--- a/poppler/GfxFont.cc
+++ b/poppler/GfxFont.cc
@@ -408,9 +408,15 @@ char *GfxFont::readExtFontFile(int *len) {
     error(-1, "External font file '%s' vanished", extFontFile->getCString());
     return NULL;
   }
-  fseek(f, 0, SEEK_END);
+  if (fseek(f, 0, SEEK_END) != 0) {
+    error(-1, "Cannot seek to end of file");
+    return NULL;
+  }
   *len = (int)ftell(f);
-  fseek(f, 0, SEEK_SET);
+  if (fseek(f, 0, SEEK_SET) != 0) {
+    error(-1, "Cannot seek to start of file");
+    return NULL;
+  }
   buf = (char *)gmalloc(*len);
   if ((int)fread(buf, 1, *len, f) != *len) {
     error(-1, "Error reading external font file '%s'",
diff --git a/poppler/PDFDoc.cc b/poppler/PDFDoc.cc
index c0c8f58..00ba925 100644
--- a/poppler/PDFDoc.cc
+++ b/poppler/PDFDoc.cc
@@ -181,6 +181,7 @@ PDFDoc::PDFDoc(BaseStream *strA, GooString *ownerPassword,
 }
 
 GBool PDFDoc::setup(GooString *ownerPassword, GooString *userPassword) {
+  if (!str->checkIO()) return false;
   str->reset();
 
   // check footer
@@ -447,6 +448,7 @@ GBool PDFDoc::saveAs(GooString *name, PDFWriteMode mode) {
     return gFalse;
   }
   outStr = new FileOutStream(f,0);
+  if (!outStr->checkIO()) return false;
   res = saveAs(outStr, mode);
   delete outStr;
   fclose(f);
@@ -489,6 +491,7 @@ GBool PDFDoc::saveWithoutChangesAs(GooString *name) {
   }
   
   outStr = new FileOutStream(f,0);
+  if (!outStr->checkIO()) return false;
   res = saveWithoutChangesAs(outStr);
   delete outStr;
 
diff --git a/poppler/Stream.cc b/poppler/Stream.cc
index 3ef7146..a8f7480 100644
--- a/poppler/Stream.cc
+++ b/poppler/Stream.cc
@@ -308,9 +308,16 @@ FileOutStream::~FileOutStream ()
   close ();
 }
 
+bool FileOutStream::checkIO ()
+{
+  if (fseek(f, 1, SEEK_SET) == 0 && fseek(f, 0, SEEK_SET) == 0) return true;
+  error(-1, "Output file not seekable");
+  return false;
+}
+
 void FileOutStream::reset ()
 {
-  fseek(f, start, SEEK_SET);
+  fseek(f, start, SEEK_SET); // ignore failure
 }
 
 void FileOutStream::close ()
@@ -652,12 +659,19 @@ FileStream::~FileStream() {
   close();
 }
 
+bool FileStream::checkIO() {
+  if (fseek(f, 1, SEEK_SET) == 0 && fseek(f, 0, SEEK_SET) == 0) return true;
+  error(-1, "File empty or not seekable");
+  return false;
+}
+
 Stream *FileStream::makeSubStream(Guint startA, GBool limitedA,
 				  Guint lengthA, Object *dictA) {
   return new FileStream(f, startA, limitedA, lengthA, dictA);
 }
 
 void FileStream::reset() {
+  // Ignore failure of any seek functions.
 #if HAVE_FSEEKO
   savePos = (Guint)ftello(f);
   fseeko(f, start, SEEK_SET);
@@ -674,6 +688,7 @@ void FileStream::reset() {
 }
 
 void FileStream::close() {
+  // Ignore failure of any seek functions.
   if (saved) {
 #if HAVE_FSEEKO
     fseeko(f, savePos, SEEK_SET);
@@ -710,6 +725,7 @@ GBool FileStream::fillBuf() {
 void FileStream::setPos(Guint pos, int dir) {
   Guint size;
 
+  // Ignore failure of any seek functions.
   if (dir >= 0) {
 #if HAVE_FSEEKO
     fseeko(f, pos, SEEK_SET);
diff --git a/poppler/Stream.h b/poppler/Stream.h
index 74152fc..3a99fa8 100644
--- a/poppler/Stream.h
+++ b/poppler/Stream.h
@@ -177,6 +177,9 @@ public:
   // Printf-like function                         2,3 because the first arg is class instance ?
   virtual void printf (const char *format, ...) = 0 ; //__attribute__((format(printf, 2,3))) = 0;
 
+  // Similar to Stream::checkIO(), this makes sure fseek() etc. will work.
+  virtual bool checkIO() = 0;
+
 private:
   int ref; // reference count
     
@@ -191,6 +194,8 @@ public:
 
   virtual ~FileOutStream ();
 
+  virtual bool checkIO();
+
   virtual void reset();
 
   virtual void close();
@@ -231,6 +236,16 @@ public:
   virtual Guint getStart() = 0;
   virtual void moveStart(int delta) = 0;
 
+  // Check that any necessary I/O for this stream is working.
+  // In particular, for file streams this happens to check
+  // that fseek() works.  Call this after constructing the
+  // stream.
+  //
+  // If something is wrong so the stream is unlikely to work,
+  // this function logs a message and returns false.
+  //
+  virtual bool checkIO() = 0;
+
 private:
 
   Object dict;
@@ -350,6 +365,7 @@ public:
   FileStream(FILE *fA, Guint startA, GBool limitedA,
 	     Guint lengthA, Object *dictA);
   virtual ~FileStream();
+  virtual bool checkIO();
   virtual Stream *makeSubStream(Guint startA, GBool limitedA,
 				Guint lengthA, Object *dictA);
   virtual StreamKind getKind() { return strFile; }
@@ -392,6 +408,7 @@ public:
 
   MemStream(char *bufA, Guint startA, Guint lengthA, Object *dictA);
   virtual ~MemStream();
+  virtual bool checkIO() { return true; }
   virtual Stream *makeSubStream(Guint start, GBool limited,
 				Guint lengthA, Object *dictA);
   virtual StreamKind getKind() { return strWeird; }
@@ -438,6 +455,7 @@ public:
 
   EmbedStream(Stream *strA, Object *dictA, GBool limitedA, Guint lengthA);
   virtual ~EmbedStream();
+  virtual bool checkIO() { return true; }
   virtual Stream *makeSubStream(Guint start, GBool limitedA,
 				Guint lengthA, Object *dictA);
   virtual StreamKind getKind() { return str->getKind(); }
diff --git a/utils/pdfinfo.cc b/utils/pdfinfo.cc
index 5dbd724..ab9a6f0 100644
--- a/utils/pdfinfo.cc
+++ b/utils/pdfinfo.cc
@@ -135,7 +135,10 @@ int main(int argc, char *argv[]) {
       Object obj;
 
       obj.initNull();
-      doc = new PDFDoc(new FileStream(stdin, 0, gFalse, 0, &obj), ownerPW, userPW);
+
+      FileStream *stream = new FileStream(stdin, 0, gFalse, 0, &obj);
+      if (!stream->checkIO()) exit(1);
+      doc = new PDFDoc(stream, ownerPW, userPW);
   }
 
   if (userPW) {
@@ -258,14 +261,14 @@ int main(int argc, char *argv[]) {
 #endif
   if (f) {
 #if HAVE_FSEEKO
-    fseeko(f, 0, SEEK_END);
-    printf("File size:      %u bytes\n", (Guint)ftello(f));
+    if (fseeko(f, 0, SEEK_END) == 0)
+      printf("File size:      %u bytes\n", (Guint)ftello(f));
 #elif HAVE_FSEEK64
-    fseek64(f, 0, SEEK_END);
-    printf("File size:      %u bytes\n", (Guint)ftell64(f));
+    if (fseek64(f, 0, SEEK_END) == 0)
+      printf("File size:      %u bytes\n", (Guint)ftell64(f));
 #else
-    fseek(f, 0, SEEK_END);
-    printf("File size:      %d bytes\n", (int)ftell(f));
+    if (fseek(f, 0, SEEK_END) == 0)
+      printf("File size:      %d bytes\n", (int)ftell(f));
 #endif
     fclose(f);
   }
diff --git a/utils/pdftoppm.cc b/utils/pdftoppm.cc
index 164679d..f61502f 100644
--- a/utils/pdftoppm.cc
+++ b/utils/pdftoppm.cc
@@ -190,7 +190,10 @@ int main(int argc, char *argv[]) {
       Object obj;
 
       obj.initNull();
-      doc = new PDFDoc(new FileStream(stdin, 0, gFalse, 0, &obj), ownerPW, userPW);
+
+      FileStream *stream = new FileStream(stdin, 0, gFalse, 0, &obj);
+      if (!stream->checkIO()) exit(1);
+      doc = new PDFDoc(stream, ownerPW, userPW);
   }
   if (userPW) {
     delete userPW;
diff --git a/utils/pdftotext.cc b/utils/pdftotext.cc
index a0caed8..c7b0a14 100644
--- a/utils/pdftotext.cc
+++ b/utils/pdftotext.cc
@@ -154,7 +154,10 @@ int main(int argc, char *argv[]) {
       Object obj;
 
       obj.initNull();
-      doc = new PDFDoc(new FileStream(stdin, 0, gFalse, 0, &obj), ownerPW, userPW);
+
+      FileStream *stream = new FileStream(stdin, 0, gFalse, 0, &obj);
+      if (!stream->checkIO()) exit(1);
+      doc = new PDFDoc(stream, ownerPW, userPW);
   }
 
   if (userPW) {