2f50aa42c
Denis Vlasenko
2006-09-08
Subject
login: use some ideas from util-linux's login. O_NONBLOCKing output on login timeout. fchmod instead of chmod (latter is racy). is_my_tty() is not needed anymore after race is fixed (is_my_tty() was racy too anyway...).
SOURCE BUG
This commit was genuinely broken at the time (not related to our build system): scripts/config/mkconfigs.c (2005-08-01 - 2006-10-05 arasi) uretilen bbconfigopts.h icine .config satirlarini kacissiz, ham newline'larla gömüyordu - gecerli C degildi, busybox'un kendi bb_mkdep araci bile parse edemiyordu (7d219aab7 ile duzeltildi, mkconfigs shell scripte cevrildi)
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Commit Diff GitHub →
loginutils/login.c+15 -25
| @@ -51,14 +51,22 @@ static inline int check_securetty(void) { return 1; } | |
| #endif | |
| - | static int is_my_tty(void); |
| static void get_username_or_die(char *buf, int size_buf); | |
| static void motd(void); | |
| + | static void nonblock(int fd) |
| + | { |
| + | fcntl(fd, F_SETFL, O_NONBLOCK | fcntl(fd, F_GETFL)); |
| + | } |
| static void alarm_handler(int sig ATTRIBUTE_UNUSED) | |
| { | |
| - | fprintf(stderr, "\r\nLogin timed out after %d seconds\r\n", TIMEOUT); |
| + | /* This is the escape hatch! Poor serial line users and the like |
| + | * arrive here when their connection is broken. |
| + | * We don't want to block here */ |
| + | nonblock(1); |
| + | nonblock(2); |
| + | bb_info_msg("\r\nLogin timed out after %d seconds\r", TIMEOUT); |
| exit(EXIT_SUCCESS); | |
| } | |
| @@ -218,13 +226,10 @@ auth_failed: | |
| } | |
| } | |
| #endif | |
| - | if (!is_my_tty()) |
| - | syslog(LOG_ERR, "unable to determine TTY name, got %s", full_tty); |
| - | |
| - | /* Try these, but don't complain if they fail |
| - | * (for example when the root fs is read only) */ |
| - | chown(full_tty, pw->pw_uid, pw->pw_gid); |
| - | chmod(full_tty, 0600); |
| + | /* Try these, but don't complain if they fail. |
| + | * _f_chown is safe wrt race t=ttyname(0);...;chown(t); */ |
| + | fchown(0, pw->pw_uid, pw->pw_gid); |
| + | fchmod(0, 0600); |
| if (ENABLE_LOGIN_SCRIPTS) { | |
| char *script = getenv("LOGIN_PRE_SUID_SCRIPT"); | |
| @@ -257,7 +262,7 @@ auth_failed: | |
| signal(SIGALRM, SIG_DFL); /* default alarm signal */ | |
| if (pw->pw_uid == 0) | |
| - | syslog(LOG_INFO, "root login %s", fromhost); |
| + | syslog(LOG_INFO, "root login%s", fromhost); |
| #ifdef CONFIG_SELINUX | |
| /* well, a simple setexeccon() here would do the job as well, | |
| * but let's play the game for now */ | |
| @@ -348,21 +353,6 @@ static int check_securetty(void) | |
| #endif | |
| - | /* returns 1 if true */ |
| - | static int is_my_tty(void) |
| - | { |
| - | struct stat by_name, by_fd; |
| - | |
| - | if (stat(full_tty, &by_name) || fstat(0, &by_fd)) |
| - | return 0; |
| - | |
| - | if (by_name.st_rdev != by_fd.st_rdev) |
| - | return 0; |
| - | else |
| - | return 1; |
| - | } |
| - | |
| - | |
| static void motd(void) | |
| { | |
| FILE *fp; | |