647746076
Denys Vlasenko
2016-10-26
Subject
ash: [REDIR] Replace copyfd by savefd and use dup2 elsewhere
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shell/ash.c+31 -27
| @@ -3760,12 +3760,12 @@ setjobctl(int on) | |
| if (--fd < 0) | |
| goto out; | |
| } | |
| + | /* fd is a tty at this point */ |
| fd = fcntl(fd, F_DUPFD, 10); | |
| - | if (ofd >= 0) |
| + | if (ofd >= 0) /* if it is "/dev/tty", close. If 0/1/2, dont */ |
| close(ofd); | |
| if (fd < 0) | |
| - | goto out; |
| - | /* fd is a tty at this point */ |
| + | goto out; /* F_DUPFD failed */ |
| close_on_exec_on(fd); | |
| while (1) { /* while we are in the background */ | |
| pgrp = tcgetpgrp(fd); | |
| @@ -5181,26 +5181,31 @@ openredirect(union node *redir) | |
| } | |
| /* | |
| - | * Copy a file descriptor to be >= to. Throws exception on error. |
| + | * Copy a file descriptor to be >= 10. Throws exception on error. |
| */ | |
| - | /* 0x800..00: bit to set in "to" to request dup2 instead of fcntl(F_DUPFD). |
| - | * old code was doing close(to) prior to copyfd() to achieve the same */ |
| - | enum { |
| - | COPYFD_EXACT = (int)~(INT_MAX), |
| - | COPYFD_RESTORE = (int)((unsigned)COPYFD_EXACT >> 1), |
| - | }; |
| static int | |
| - | copyfd(int from, int to) |
| + | savefd(int from) |
| { | |
| int newfd; | |
| + | int err; |
| - | if (to & COPYFD_EXACT) { |
| - | to &= ~COPYFD_EXACT; |
| - | /*if (from != to)*/ |
| - | newfd = dup2(from, to); |
| - | } else { |
| - | newfd = fcntl(from, F_DUPFD, to); |
| + | newfd = fcntl(from, F_DUPFD, 10); |
| + | err = newfd < 0 ? errno : 0; |
| + | if (err != EBADF) { |
| + | if (err) |
| + | ash_msg_and_raise_error("%d: %m", from); |
| + | close(from); |
| + | fcntl(newfd, F_SETFD, FD_CLOEXEC); |
| } | |
| + | |
| + | return newfd; |
| + | } |
| + | static int |
| + | dup2_or_raise(int from, int to) |
| + | { |
| + | int newfd; |
| + | |
| + | newfd = (from != to) ? dup2(from, to) : to; |
| if (newfd < 0) { | |
| /* Happens when source fd is not open: try "echo >&99" */ | |
| ash_msg_and_raise_error("%d: %m", from); | |
| @@ -5218,6 +5223,9 @@ struct redirtab { | |
| struct two_fd_t two_fd[]; | |
| }; | |
| #define redirlist (G_var.redirlist) | |
| + | enum { |
| + | COPYFD_RESTORE = (int)~(INT_MAX), |
| + | }; |
| static int | |
| need_to_remember(struct redirtab *rp, int fd) | |
| @@ -5391,10 +5399,10 @@ redirect(union node *redir, int flags) | |
| if (fd != -1) | |
| close(fd); | |
| } else { | |
| - | copyfd(redir->ndup.dupfd, fd | COPYFD_EXACT); |
| + | dup2_or_raise(redir->ndup.dupfd, fd); |
| } | |
| } else if (fd != newfd) { /* move newfd to fd */ | |
| - | copyfd(newfd, fd | COPYFD_EXACT); |
| + | dup2_or_raise(newfd, fd); |
| #if ENABLE_ASH_BASH_COMPAT | |
| if (!(redir->nfile.type == NTO2 && fd == 2)) | |
| #endif | |
| @@ -5440,7 +5448,7 @@ popredir(int drop, int restore) | |
| if (!drop || (restore && (copy & COPYFD_RESTORE))) { | |
| copy &= ~COPYFD_RESTORE; | |
| /*close(fd);*/ | |
| - | copyfd(copy, fd | COPYFD_EXACT); |
| + | dup2_or_raise(copy, fd); |
| } | |
| close(copy & ~COPYFD_RESTORE); | |
| } | |
| @@ -5894,7 +5902,7 @@ evalbackcmd(union node *n, struct backcmd *result) | |
| close(pip[0]); | |
| if (pip[1] != 1) { | |
| /*close(1);*/ | |
| - | copyfd(pip[1], 1 | COPYFD_EXACT); |
| + | dup2_or_raise(pip[1], 1); |
| close(pip[1]); | |
| } | |
| /* TODO: eflag clearing makes the following not abort: | |
| @@ -10204,7 +10212,6 @@ static int | |
| setinputfile(const char *fname, int flags) | |
| { | |
| int fd; | |
| - | int fd2; |
| INT_OFF; | |
| fd = open(fname, O_RDONLY); | |
| @@ -10214,11 +10221,8 @@ setinputfile(const char *fname, int flags) | |
| exitstatus = 127; | |
| ash_msg_and_raise_error("can't open '%s'", fname); | |
| } | |
| - | if (fd < 10) { |
| - | fd2 = copyfd(fd, 10); |
| - | close(fd); |
| - | fd = fd2; |
| - | } |
| + | if (fd < 10) |
| + | fd = savefd(fd); |
| setinputfd(fd, flags & INPUT_PUSH_FILE); | |
| out: | |
| INT_ON; | |