[hackers] [ubase] Properly match (ttymaj, ttymin) pairs to tty names in /dev || sin

From: <git_AT_suckless.org>
Date: Fri, 16 Jan 2015 16:55:15 +0100 (CET)

commit d76319f838dfb42c13c099012e72ca11d37d7178
Author: sin <sin_AT_2f30.org>
Date: Fri Jan 16 15:32:55 2015 +0000

    Properly match (ttymaj, ttymin) pairs to tty names in /dev
    
    For the common case where we have pts/ or tty do it straight
    away. Otherwise traverse /dev for a match. This fixes ps(1) when
    it is executed over a serial terminal with tty names like ttyAMA0.

diff --git a/libutil/tty.c b/libutil/tty.c
index 4bd24c0..9078e37 100644
--- a/libutil/tty.c
+++ b/libutil/tty.c
_AT_@ -1,7 +1,13 @@
 /* See LICENSE file for copyright and license details. */
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <dirent.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 #include "../util.h"
 
_AT_@ -12,28 +18,63 @@ devtotty(int dev, int *tty_maj, int *tty_min)
         *tty_min = (dev & 0xff) | ((dev >> 12) & 0xfff00);
 }
 
-char *
-ttytostr(int tty_maj, int tty_min)
+int
+ttytostr(int tty_maj, int tty_min, char *str, size_t n)
 {
- const char *pts = "pts/";
- const char *tty = "tty";
- char *ttystr;
- size_t len;
-
- /* Up to 10k ttys */
- len = strlen(pts) + 4 + 1;
- ttystr = emalloc(len);
+ struct stat sb;
+ struct dirent *dp;
+ DIR *dirp;
+ char path[PATH_MAX];
+
         switch (tty_maj) {
         case 136:
- snprintf(ttystr, len, "%s%d", pts, tty_min);
- break;
+ snprintf(str, n, "pts/%d", tty_min);
+ return 0;
         case 4:
- snprintf(ttystr, len, "%s%d", tty, tty_min);
- break;
+ snprintf(str, n, "tty%d", tty_min);
+ return 0;
         default:
- ttystr[0] = '?';
- ttystr[1] = '\0';
+ str[0] = '?';
+ str[1] = '\0';
                 break;
         }
- return ttystr;
+
+ dirp = opendir("/dev");
+ if (!dirp) {
+ weprintf("opendir /dev:");
+ return -1;
+ }
+
+ while ((dp = readdir(dirp))) {
+ if (!strcmp(dp->d_name, ".") ||
+ !strcmp(dp->d_name, ".."))
+ continue;
+
+ if (strlcpy(path, "/dev/", sizeof(path)) >= sizeof(path)) {
+ weprintf("path too long\n");
+ return -1;
+ }
+ if (strlcat(path, dp->d_name, sizeof(path)) >= sizeof(path)) {
+ weprintf("path too long\n");
+ return -1;
+ }
+
+ if (stat(path, &sb) < 0) {
+ weprintf("stat %s:", dp->d_name);
+ return -1;
+ }
+
+ if ((int)major(sb.st_rdev) == tty_maj &&
+ (int)minor(sb.st_rdev) == tty_min) {
+ strlcpy(str, dp->d_name, n);
+ break;
+ }
+ }
+
+ if (closedir(dirp) < 0) {
+ weprintf("closedir /dev:");
+ return -1;
+ }
+
+ return 0;
 }
diff --git a/ps.c b/ps.c
index 2f555d8..14f95c8 100644
--- a/ps.c
+++ b/ps.c
_AT_@ -70,7 +70,7 @@ psout(struct procstat *ps)
         struct procstatus pstatus;
         char cmdline[BUFSIZ], *cmd;
         char buf[BUFSIZ];
- char *ttystr, *myttystr;
+ char ttystr[PATH_MAX], *myttystr;
         int tty_maj, tty_min;
         uid_t myeuid;
         unsigned sutime;
_AT_@ -86,16 +86,13 @@ psout(struct procstat *ps)
                         return;
 
         devtotty(ps->tty_nr, &tty_maj, &tty_min);
- ttystr = ttytostr(tty_maj, tty_min);
+ ttytostr(tty_maj, tty_min, ttystr, sizeof(ttystr));
 
         /* Only print processes that are associated with
          * a terminal and they are not session leaders */
- if (flags & PS_aflag) {
- if (ps->pid == ps->sid || ttystr[0] == '?') {
- free(ttystr);
+ if (flags & PS_aflag)
+ if (ps->pid == ps->sid || ttystr[0] == '?')
                         return;
- }
- }
 
         if (parsestatus(ps->pid, &pstatus) < 0)
                 return;
_AT_@ -106,10 +103,8 @@ psout(struct procstat *ps)
         if (!(flags & (PS_aflag | PS_Aflag | PS_dflag))) {
                 myttystr = ttyname(0);
                 if (myttystr) {
- if (strcmp(myttystr + strlen("/dev/"), ttystr)) {
- free(ttystr);
+ if (strcmp(myttystr + strlen("/dev/"), ttystr))
                                 return;
- }
                 } else {
                         /* The invoker has no controlling terminal - just
                          * go ahead and print the processes anyway */
_AT_@ -117,10 +112,8 @@ psout(struct procstat *ps)
                         ttystr[1] = '\0';
                 }
                 myeuid = geteuid();
- if (myeuid != pstatus.euid) {
- free(ttystr);
+ if (myeuid != pstatus.euid)
                         return;
- }
         }
 
         sutime = (ps->stime + ps->utime) / sysconf(_SC_CLK_TCK);
_AT_@ -166,7 +159,6 @@ psout(struct procstat *ps)
                 else
                         printf("%s\n", buf);
         }
- free(ttystr);
 }
 
 static void
diff --git a/util.h b/util.h
index cb75bc6..d9b5f1a 100644
--- a/util.h
+++ b/util.h
_AT_@ -50,4 +50,4 @@ size_t strlcpy(char *, const char *, size_t);
 
 /* tty.c */
 void devtotty(int, int *, int *);
-char *ttytostr(int, int);
+int ttytostr(int, int, char *, size_t);
Received on Fri Jan 16 2015 - 16:55:15 CET