xstrncpy saga

	* src/fileio.c (file_name_as_directory): Use xstrncpy and change
	prototype to take in buffer length.

	* src/fileio.c (directory_file_name): Ditto.

	* src/fileio.c (Ffile_name_as_directory): properly call
	file_name_as_directory with buffer length.
	* src/fileio.c (Fdirectory_file_name): ditto.

	* src/fileio.c (Fexpand_file_name): Use xstrncat instead of strcat.

	* src/fileio.c (Fdirectory_file_name): properly call
	directory_file_name with buffer length.

	* src/fileio.c (Fsubstitute_in_file_name): use xstrncpy instead of
	strcpy keeping track of buffer availability.

Signed-off-by: Nelson Ferreira <nelson.ferreira@ieee.org>

diff --git a/src/fileio.c b/src/fileio.c
index 995a573..bae112a 100644 (file)
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -601,17 +601,18 @@ get a current directory to run processes in.
        return Ffile_name_directory(filename);
 }
 \f
-static char *file_name_as_directory(char *out, char *in)
+static char *file_name_as_directory(char *out, const char *in, size_t len)
 {
        /* This function cannot GC */
        int size = strlen(in);
 
        if (size == 0) {
+               assert(len >= 3);
                out[0] = '.';
                out[1] = DIRECTORY_SEP;
                out[2] = '\0';
        } else {
-               strcpy(out, in);
+               xstrncpy(out, in, len);
                /* Append a slash if necessary */
                if (!IS_ANY_SEP(out[size - 1])) {
                        out[size] = DIRECTORY_SEP;
@@ -633,8 +634,9 @@ except for (file-name-as-directory \"\") => \"./\".
       (filename))
 {
        /* This function can GC.  GC checked 2000-07-28 ben */
-       char *buf;
-       Lisp_Object handler;
+       size_t len = 0;
+       char *buf = NULL;
+       Lisp_Object handler = Qnil;
 
        CHECK_STRING(filename);
 
@@ -645,9 +647,10 @@ except for (file-name-as-directory \"\") => \"./\".
                return call2_check_string(handler, Qfile_name_as_directory,
                                          filename);
 
-       buf = (char *)alloca(XSTRING_LENGTH(filename) + 10);
+       len = XSTRING_LENGTH(filename) + 10;
+       buf = (char *)alloca(len);
        return build_string(file_name_as_directory
-                           (buf, (char *)XSTRING_DATA(filename)));
+                           (buf, (char*)XSTRING_DATA(filename), len));
 }
 \f
 /*
@@ -657,13 +660,13 @@ except for (file-name-as-directory \"\") => \"./\".
  * Value is nonzero if the string output is different from the input.
  */
 
-static int directory_file_name(const char *src, char *dst)
+static int directory_file_name(const char *src, char *dst, size_t len)
 {
        /* This function cannot GC */
        long slen = strlen(src);
        /* Process as Unix format: just remove any final slash.
           But leave "/" unchanged; do not change it to "".  */
-       strcpy(dst, src);
+       xstrncpy(dst, src, len);
        if (slen > 1 && IS_DIRECTORY_SEP(dst[slen - 1])
            )
                dst[slen - 1] = 0;
@@ -680,7 +683,8 @@ In Unix-syntax, this function just removes the final slash.
       (directory))
 {
        /* This function can GC.  GC checked 2000-07-28 ben */
-       char *buf;
+       size_t len = 0;
+       char *buf = NULL;
        Lisp_Object handler;
 
        CHECK_STRING(directory);
@@ -696,8 +700,9 @@ In Unix-syntax, this function just removes the final slash.
        if (!NILP(handler))
                return call2_check_string(handler, Qdirectory_file_name,
                                          directory);
-       buf = (char *)alloca(XSTRING_LENGTH(directory) + 20);
-       directory_file_name((char *)XSTRING_DATA(directory), buf);
+       len = XSTRING_LENGTH(directory) + 20;
+       buf = (char *)alloca(len);
+       directory_file_name((char *)XSTRING_DATA(directory), buf, len);
        return build_string(buf);
 }
 \f
@@ -1024,12 +1029,12 @@ See also the function `substitute-in-file-name'.
 
        if (newdir) {
                if (nm[0] == 0 || IS_DIRECTORY_SEP(nm[0]))
-                       strcpy((char *)target, (char *)newdir);
+                       xstrncpy((char *)target, (char *)newdir, tlen);
                else
-                       file_name_as_directory((char *)target, (char *)newdir);
+                       file_name_as_directory((char *)target, (char *)newdir, tlen);
        }
 
-       strcat((char *)target, (char *)nm);
+       xstrncat((char *)target, (char *)nm, tlen);
 
        /* ASSERT (IS_DIRECTORY_SEP (target[0])) if not VMS */
 
@@ -1245,6 +1250,7 @@ If `/~' appears, all of FILENAME through that `/' is discarded.
        Bufbyte *target = 0;
        int total = 0;
        int substituted = 0;
+       size_t avail = 0;
        Bufbyte *xnm;
        Lisp_Object handler;
 
@@ -1321,19 +1327,22 @@ If `/~' appears, all of FILENAME through that `/' is discarded.
 
        /* If substitution required, recopy the filename and do it */
        /* Make space in stack frame for the new copy */
-       xnm = (Bufbyte *) alloca(XSTRING_LENGTH(filename) + total + 1);
+       avail = XSTRING_LENGTH(filename) + total + 1;
+       xnm = (Bufbyte *) alloca(avail);
        x = xnm;
 
        /* Copy the rest of the name through, replacing $ constructs with values */
        for (p = nm; *p;)
-               if (*p != '$')
+               if (*p != '$') {
                        *x++ = *p++;
-               else {
+                       avail--;
+               } else {
                        p++;
                        if (p == endp)
                                goto badsubst;
                        else if (*p == '$') {
                                *x++ = *p++;
+                               avail--;
                                continue;
                        } else if (*p == '{') {
                                o = ++p;
@@ -1359,8 +1368,9 @@ If `/~' appears, all of FILENAME through that `/' is discarded.
                        if (!o)
                                goto badvar;
 
-                       strcpy((char *)x, (char *)o);
+                       xstrncpy((char *)x, (char *)o, avail);
                        x += strlen((char *)o);
+                       avail -= strlen((char *)o);
                }
 
        *x = 0;