Improve etags I/O error reporting

* lib-src/etags.c:
Don't include sys/types.h and sys/stat.h; no longer needed.
(infilename): New static var.
(process_file_name): Don't call 'stat'.  Instead, just open the
file for reading and report any errors.  Don't bother making
a copy of the file argument; it's not needed.  Be more careful to
use the failing errno when reporting an error.
Quote the real name better (though no perfectly)
when passing it to the shell.
(reset_input): New function, which reports I/O errors.
All uses of 'rewind' changed to use this function.
(perhaps_more_input): New function, which also checks for
I/O errors.  All uses of 'feof' changed to use this function.
(analyze_regex): Report an error if fclose fails.
(readline_internal): Report an error if getc fails.
(etags_mktmp): Return an error if close fails.

1 files changed, 103 insertions, 80 deletions

diff --git a/lib-src/etags.c b/lib-src/etags.c
index ea337d41008..48d2299410a 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -127,8 +127,6 @@ char pot_etags_version[] = "@(#) pot revision number is 17.38.1.4";
 #include <sysstdio.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <binary-io.h>
 #include <c-ctype.h>
 #include <c-strcase.h>
@@ -355,7 +353,7 @@ static void just_read_file (FILE *);
 
 static language *get_language_from_langname (const char *);
 static void readline (linebuffer *, FILE *);
-static long readline_internal (linebuffer *, FILE *);
+static long readline_internal (linebuffer *, FILE *, char const *);
 static bool nocase_tail (const char *);
 static void get_tag (char *, char **);
 
@@ -407,6 +405,7 @@ static ptrdiff_t whatlen_max;	/* maximum length of any 'what' member */
 
 static fdesc *fdhead;           /* head of file description list */
 static fdesc *curfdp;           /* current file description */
+static char *infilename;        /* current input file name */
 static int lineno;              /* line number of current line */
 static long charno;             /* current character number */
 static long linecharno;         /* charno of start of current line */
@@ -1247,7 +1246,7 @@ main (int argc, char **argv)
                   if (parsing_stdin)
                     fatal ("cannot parse standard input AND read file names from it",
                            (char *)NULL);
-                  while (readline_internal (&filename_lb, stdin) > 0)
+                  while (readline_internal (&filename_lb, stdin, "-") > 0)
                     process_file_name (filename_lb.buffer, lang);
                 }
               else
@@ -1470,7 +1469,6 @@ get_language_from_filename (char *file, int case_sensitive)
 static void
 process_file_name (char *file, language *lang)
 {
-  struct stat stat_buf;
   FILE *inf;
   fdesc *fdp;
   compressor *compr;
@@ -1487,13 +1485,13 @@ process_file_name (char *file, language *lang)
   compr = get_compressor_from_suffix (file, &ext);
   if (compr)
     {
-      real_name = compressed_name = savestr (file);
+      compressed_name = file;
       uncompressed_name = savenstr (file, ext - file);
     }
   else
     {
       compressed_name = NULL;
-      real_name = uncompressed_name = savestr (file);
+      uncompressed_name = file;
     }
 
   /* If the canonicalized uncompressed name
@@ -1505,83 +1503,91 @@ process_file_name (char *file, language *lang)
         goto cleanup;
     }
 
-  if (stat (real_name, &stat_buf) != 0)
+  inf = fopen (file, "r" FOPEN_BINARY);
+  if (inf)
+    real_name = file;
+  else
     {
-      /* Reset real_name and try with a different name. */
-      real_name = NULL;
-      if (compressed_name != NULL) /* try with the given suffix */
+      int file_errno = errno;
+      if (compressed_name)
         {
-          if (stat (uncompressed_name, &stat_buf) == 0)
+          /* Try with the given suffix.  */
+          inf = fopen (uncompressed_name, "r" FOPEN_BINARY);
+          if (inf)
             real_name = uncompressed_name;
         }
-      else                      /* try all possible suffixes */
+      else
         {
+          /* Try all possible suffixes.  */
           for (compr = compressors; compr->suffix != NULL; compr++)
             {
               compressed_name = concat (file, ".", compr->suffix);
-              if (stat (compressed_name, &stat_buf) != 0)
+              inf = fopen (compressed_name, "r" FOPEN_BINARY);
+              if (inf)
+                {
+                  real_name = compressed_name;
+                  break;
+                }
+              if (MSDOS)
                 {
-                  if (MSDOS)
+                  char *suf = compressed_name + strlen (file);
+                  size_t suflen = strlen (compr->suffix) + 1;
+                  for ( ; suf[1]; suf++, suflen--)
                     {
-                      char *suf = compressed_name + strlen (file);
-                      size_t suflen = strlen (compr->suffix) + 1;
-                      for ( ; suf[1]; suf++, suflen--)
+                      memmove (suf, suf + 1, suflen);
+                      inf = fopen (compressed_name, "r" FOPEN_BINARY);
+                      if (inf)
                         {
-                          memmove (suf, suf + 1, suflen);
-                          if (stat (compressed_name, &stat_buf) == 0)
-                            {
-                              real_name = compressed_name;
-                              break;
-                            }
+                          real_name = compressed_name;
+                          break;
                         }
-                      if (real_name != NULL)
-                        break;
-                    } /* MSDOS */
-                  free (compressed_name);
-                  compressed_name = NULL;
-                }
-              else
-                {
-                  real_name = compressed_name;
-                  break;
+                    }
+                  if (inf)
+                    break;
                 }
+              free (compressed_name);
+              compressed_name = NULL;
             }
         }
-      if (real_name == NULL)
+      if (! inf)
         {
+          errno = file_errno;
           perror (file);
           goto cleanup;
         }
-    } /* try with a different name */
-
-  if (!S_ISREG (stat_buf.st_mode))
-    {
-      error ("skipping %s: it is not a regular file.", real_name);
-      goto cleanup;
     }
+
   if (real_name == compressed_name)
     {
+      fclose (inf);
       tmp_name = etags_mktmp ();
       if (!tmp_name)
         inf = NULL;
       else
         {
-          char *cmd1 = concat (compr->command, " ", real_name);
-          char *cmd = concat (cmd1, " > ", tmp_name);
+          char *cmd1 = concat (compr->command, " '", real_name);
+          char *cmd = concat (cmd1, "' > ", tmp_name);
           free (cmd1);
+          int tmp_errno;
           if (system (cmd) == -1)
-            inf = NULL;
+            {
+              inf = NULL;
+              tmp_errno = EINVAL;
+            }
           else
-            inf = fopen (tmp_name, "r" FOPEN_BINARY);
+            {
+              inf = fopen (tmp_name, "r" FOPEN_BINARY);
+              tmp_errno = errno;
+            }
           free (cmd);
+          errno = tmp_errno;
+        }
+
+      if (!inf)
+        {
+          perror (real_name);
+          goto cleanup;
         }
-    }
-  else
-    inf = fopen (real_name, "r" FOPEN_BINARY);
-  if (inf == NULL)
-    {
-      perror (real_name);
-      goto cleanup;
     }
 
   process_file (inf, uncompressed_name, lang);
@@ -1596,8 +1602,10 @@ process_file_name (char *file, language *lang)
     pfatal (file);
 
  cleanup:
-  free (compressed_name);
-  free (uncompressed_name);
+  if (compressed_name != file)
+    free (compressed_name);
+  if (uncompressed_name != file)
+    free (uncompressed_name);
   last_node = NULL;
   curfdp = NULL;
   return;
@@ -1609,6 +1617,7 @@ process_file (FILE *fh, char *fn, language *lang)
   static const fdesc emptyfdesc;
   fdesc *fdp;
 
+  infilename = fn;
   /* Create a new input file description entry. */
   fdp = xnew (1, fdesc);
   *fdp = emptyfdesc;
@@ -1672,6 +1681,13 @@ process_file (FILE *fh, char *fn, language *lang)
     }
 }
 
+static void
+reset_input (FILE *inf)
+{
+  if (fseek (inf, 0, SEEK_SET) != 0)
+    perror (infilename);
+}
+
 /*
  * This routine opens the specified file and calls the function
  * which finds the function and type definitions.
@@ -1702,7 +1718,7 @@ find_entries (FILE *inf)
 
   /* Else look for sharp-bang as the first two characters. */
   if (parser == NULL
-      && readline_internal (&lb, inf) > 0
+      && readline_internal (&lb, inf, infilename) > 0
       && lb.len >= 2
       && lb.buffer[0] == '#'
       && lb.buffer[1] == '!')
@@ -1731,7 +1747,7 @@ find_entries (FILE *inf)
         }
     }
 
-  rewind (inf);
+  reset_input (inf);
 
   /* Else try to guess the language given the case insensitive file name. */
   if (parser == NULL)
@@ -1755,7 +1771,7 @@ find_entries (FILE *inf)
       if (old_last_node == last_node)
         /* No Fortran entries found.  Try C. */
         {
-          rewind (inf);
+          reset_input (inf);
           curfdp->lang = get_language_from_langname (cplusplus ? "c++" : "c");
           find_entries (inf);
         }
@@ -2965,7 +2981,7 @@ do {									\
 
 #define CNL()                                                           \
 do {                                                                    \
-  CNL_SAVE_DEFINEDEF();                                                 \
+  CNL_SAVE_DEFINEDEF ();                                                \
   if (savetoken.valid)                                                  \
     {                                                                   \
       token = savetoken;                                                \
@@ -2994,6 +3010,12 @@ make_C_tag (bool isfun)
   token.valid = false;
 }
 
+static bool
+perhaps_more_input (FILE *inf)
+{
+  return !feof (inf) && !ferror (inf);
+}
+
 
 /*
  * C_entries ()
@@ -3051,7 +3073,7 @@ C_entries (int c_ext, FILE *inf)
     { qualifier = "::"; qlen = 2; }
 
 
-  while (!feof (inf))
+  while (perhaps_more_input (inf))
     {
       c = *lp++;
       if (c == '\\')
@@ -3892,13 +3914,10 @@ Yacc_entries (FILE *inf)
 
 /* Useful macros. */
 #define LOOP_ON_INPUT_LINES(file_pointer, line_buffer, char_pointer)    \
-  for (;                        /* loop initialization */               \
-       !feof (file_pointer)     /* loop test */                         \
-       &&                       /* instructions at start of loop */     \
-          (readline (&line_buffer, file_pointer),                       \
-           char_pointer = line_buffer.buffer,                           \
-           true);                                                       \
-      )
+  while (perhaps_more_input (file_pointer)                              \
+         && (readline (&(line_buffer), file_pointer),                   \
+             (char_pointer) = (line_buffer).buffer,                     \
+             true))                                                     \
 
 #define LOOKING_AT(cp, kw)  /* kw is the keyword, a literal string */   \
   ((assert ("" kw), true)   /* syntax error if not a literal string */  \
@@ -3919,7 +3938,7 @@ Yacc_entries (FILE *inf)
 static void
 just_read_file (FILE *inf)
 {
-  while (!feof (inf))
+  while (perhaps_more_input (inf))
     readline (&lb, inf);
 }
 
@@ -4074,7 +4093,7 @@ Ada_getit (FILE *inf, const char *name_qualifier)
   char *name;
   char c;
 
-  while (!feof (inf))
+  while (perhaps_more_input (inf))
     {
       dbp = skip_spaces (dbp);
       if (*dbp == '\0'
@@ -4576,7 +4595,7 @@ Pascal_functions (FILE *inf)
   verify_tag = false;           /* check if "extern" is ahead        */
 
 
-  while (!feof (inf))           /* long main loop to get next char */
+  while (perhaps_more_input (inf)) /* long main loop to get next char */
     {
       c = *dbp++;
       if (c == '\0')            /* if end of line */
@@ -5033,7 +5052,7 @@ TEX_mode (FILE *inf)
       TEX_opgrp = '<';
       TEX_clgrp = '>';
     }
-  rewind (inf);
+  reset_input (inf);
 }
 
 /* Read environment and prepend it to the default string.
@@ -5279,7 +5298,7 @@ prolog_skip_comment (linebuffer *plb, FILE *inf)
           return;
       readline (plb, inf);
     }
-  while (!feof (inf));
+  while (perhaps_more_input (inf));
 }
 
 /*
@@ -5629,10 +5648,11 @@ analyze_regex (char *regex_arg)
         if (regexfp == NULL)
           pfatal (regexfile);
         linebuffer_init (&regexbuf);
-        while (readline_internal (&regexbuf, regexfp) > 0)
+        while (readline_internal (&regexbuf, regexfp, regexfile) > 0)
           analyze_regex (regexbuf.buffer);
         free (regexbuf.buffer);
-        fclose (regexfp);
+        if (fclose (regexfp) != 0)
+          pfatal (regexfile);
       }
       break;
 
@@ -5972,11 +5992,11 @@ get_tag (register char *bp, char **namepp)
  * appended to `filebuf'.
  */
 static long
-readline_internal (linebuffer *lbp, register FILE *stream)
+readline_internal (linebuffer *lbp, FILE *stream, char const *filename)
 {
   char *buffer = lbp->buffer;
-  register char *p = lbp->buffer;
-  register char *pend;
+  char *p = lbp->buffer;
+  char *pend;
   int chars_deleted;
 
   pend = p + lbp->size;         /* Separate to avoid 386/IX compiler bug.  */
@@ -5995,6 +6015,8 @@ readline_internal (linebuffer *lbp, register FILE *stream)
         }
       if (c == EOF)
         {
+          if (ferror (stream))
+            perror (filename);
           *p = '\0';
           chars_deleted = 0;
           break;
@@ -6055,7 +6077,7 @@ readline (linebuffer *lbp, FILE *stream)
   long result;
 
   linecharno = charno;          /* update global char number of line start */
-  result = readline_internal (lbp, stream); /* read line */
+  result = readline_internal (lbp, stream, infilename); /* read line */
   lineno += 1;                  /* increment global line number */
   charno += result;             /* increment global char number */
 
@@ -6386,13 +6408,13 @@ etags_mktmp (void)
 
   char *templt = concat (tmpdir, slash, "etXXXXXX");
   int fd = mkostemp (templt, O_CLOEXEC);
-  if (fd < 0)
+  if (fd < 0 || close (fd) != 0)
     {
+      int temp_errno = errno;
       free (templt);
+      errno = temp_errno;
       templt = NULL;
     }
-  else
-    close (fd);
 
 #if defined (DOS_NT)
   /* The file name will be used in shell redirection, so it needs to have
@@ -6402,6 +6424,7 @@ etags_mktmp (void)
     if (*p == '/')
       *p = '\\';
 #endif
+
   return templt;
 }