[src/trunk]: src/lib/libc/gen PR/28183: Brian Marcotte: Getty eats the last c...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/43984fe123f8
branches:  trunk
changeset: 571090:43984fe123f8
user:      christos <christos%NetBSD.org@localhost>
date:      Wed Nov 10 23:59:06 2004 +0000

description:
PR/28183: Brian Marcotte: Getty eats the last character of the last field.
As Brian reports the bug is in skip(). The logic on end of line is broken.

- fix the bug which can cause buf[-1] to be written.
- don't leave the line buffer allocated on end of file.
- KNF
- use __func__ instead of hard-coding the function name.
- don't use needlessly global variables

diffstat:

 lib/libc/gen/getttyent.c |  94 ++++++++++++++++++++++++-----------------------
 1 files changed, 48 insertions(+), 46 deletions(-)

diffs (220 lines):

diff -r 08a977ba0f5c -r 43984fe123f8 lib/libc/gen/getttyent.c
--- a/lib/libc/gen/getttyent.c  Wed Nov 10 21:30:29 2004 +0000
+++ b/lib/libc/gen/getttyent.c  Wed Nov 10 23:59:06 2004 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: getttyent.c,v 1.20 2003/08/07 16:42:51 agc Exp $       */
+/*     $NetBSD: getttyent.c,v 1.21 2004/11/10 23:59:06 christos Exp $  */
 
 /*
  * Copyright (c) 1989, 1993
@@ -34,7 +34,7 @@
 #if 0
 static char sccsid[] = "@(#)getttyent.c        8.1 (Berkeley) 6/4/93";
 #else
-__RCSID("$NetBSD: getttyent.c,v 1.20 2003/08/07 16:42:51 agc Exp $");
+__RCSID("$NetBSD: getttyent.c,v 1.21 2004/11/10 23:59:06 christos Exp $");
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -56,15 +56,13 @@
 __weak_alias(setttyent,_setttyent)
 #endif
 
-static char zapchar;
 static FILE *tf;
 static size_t lineno = 0;
-static char *skip __P((char *));
-static char *value __P((char *));
+static char *skip(char *, char *);
+static char *value(char *);
 
 struct ttyent *
-getttynam(tty)
-       const char *tty;
+getttynam(const char *tty)
 {
        struct ttyent *t;
 
@@ -79,51 +77,53 @@
 }
 
 struct ttyent *
-getttyent()
+getttyent(void)
 {
        static struct ttyent tty;
        int c;
        char *p;
        size_t len;
        static char *line = NULL;
+       char zapchar;
+
+       if (line)
+               free(line);
 
        if (!tf && !setttyent())
-               return (NULL);
-       if (line)
-               free(line);
+               return NULL;
+
        for (;;) {
                errno = 0;
                line = fparseln(tf, &len, &lineno, NULL, FPARSELN_UNESCALL);
                if (line == NULL) {
                        if (errno != 0)
-                               warn("gettyent");
+                               warn(__func__);
                        return NULL;
                }
-               for (p = line; *p && isspace((unsigned char) *p); p++)
+               for (p = line; *p && isspace((unsigned char)*p); p++)
                        continue;
                if (*p && *p != '#')
                        break;
                free(line);
        }
 
-       zapchar = 0;
        tty.ty_name = p;
-       p = skip(p);
-       if (!*(tty.ty_getty = p))
+       p = skip(p, &zapchar);
+       if (*(tty.ty_getty = p) == '\0')
                tty.ty_getty = tty.ty_type = NULL;
        else {
-               p = skip(p);
-               if (!*(tty.ty_type = p))
+               p = skip(p, &zapchar);
+               if (*(tty.ty_type = p) == '\0')
                        tty.ty_type = NULL;
                else
-                       p = skip(p);
+                       p = skip(p, &zapchar);
        }
        tty.ty_status = 0;
        tty.ty_window = NULL;
 
 #define        scmp(e) !strncmp(p, e, sizeof(e) - 1) && (isspace((unsigned char) p[sizeof(e) - 1]) || p[sizeof(e) - 1] == '\0')
 #define        vcmp(e) !strncmp(p, e, sizeof(e) - 1) && p[sizeof(e) - 1] == '='
-       for (; *p; p = skip(p)) {
+       for (; *p; p = skip(p, &zapchar)) {
                if (scmp(_TTYS_OFF))
                        tty.ty_status &= ~TTY_ON;
                else if (scmp(_TTYS_ON))
@@ -145,19 +145,19 @@
                else if (vcmp(_TTYS_CLASS))
                        tty.ty_class = value(p);
                else
-                       warnx("gettyent: %s, %lu: unknown option `%s'",
-                           _PATH_TTYS, (unsigned long)lineno, p);
+                       warnx("%s: %s, %lu: unknown option `%s'",
+                           __func__, _PATH_TTYS, (unsigned long)lineno, p);
        }
 
        if (zapchar == '#' || *p == '#')
                while ((c = *++p) == ' ' || c == '\t')
-                       ;
+                       continue;
        tty.ty_comment = p;
-       if (*p == 0)
-               tty.ty_comment = 0;
+       if (*p == '\0')
+               tty.ty_comment = NULL;
        if ((p = strchr(p, '\n')) != NULL)
                *p = '\0';
-       return (&tty);
+       return &tty;
 }
 
 #define        QUOTED  1
@@ -167,13 +167,13 @@
  * the next field.
  */
 static char *
-skip(p)
-       char *p;
+skip(char *p, char *zapchar)
 {
        char *t;
        int c, q;
 
        _DIAGASSERT(p != NULL);
+       *zapchar = '\0';
 
        for (q = 0, t = p; (c = *p) != '\0'; p++) {
                if (c == '"') {
@@ -186,53 +186,55 @@
                if (q == QUOTED)
                        continue;
                if (c == '#') {
-                       zapchar = c;
-                       *p = 0;
-                       break;
+                       *zapchar = c;
+                       *p = '\0';
+                       *--t = '\0';
+                       return p;
                }
                if (c == '\t' || c == ' ' || c == '\n') {
-                       zapchar = c;
-                       *p++ = 0;
+                       *zapchar = c;
+                       *p++ = '\0';
                        while ((c = *p) == '\t' || c == ' ' || c == '\n')
                                p++;
-                       break;
+                       *--t = '\0';
+                       return p;
                }
        }
-       *--t = '\0';
-       return (p);
+       if (t != p)
+               *t = '\0';
+       return p;
 }
 
 static char *
-value(p)
-       char *p;
+value(char *p)
 {
 
        _DIAGASSERT(p != NULL);
 
-       return ((p = strchr(p, '=')) ? ++p : NULL);
+       return (p = strchr(p, '=')) != NULL ? ++p : NULL;
 }
 
 int
-setttyent()
+setttyent(void)
 {
        lineno = 0;
        if (tf) {
                rewind(tf);
-               return (1);
+               return 1;
        } else if ((tf = fopen(_PATH_TTYS, "r")) != NULL)
-               return (1);
-       return (0);
+               return 1;
+       return 0;
 }
 
 int
-endttyent()
+endttyent(void)
 {
        int rval;
 
        if (tf) {
                rval = !(fclose(tf) == EOF);
                tf = NULL;
-               return (rval);
+               return rval;
        }
-       return (1);
+       return 1;
 }