diff options
| -rw-r--r-- | include/libbb.h | 24 | ||||
| -rw-r--r-- | shell/hush.c | 201 | ||||
| -rw-r--r-- | shell/hush_test/hush-misc/redir_script.right | 1 | ||||
| -rwxr-xr-x | shell/hush_test/hush-misc/redir_script.tests | 29 |
4 files changed, 186 insertions, 69 deletions
diff --git a/include/libbb.h b/include/libbb.h index e39021e..b2e4299 100644 --- a/include/libbb.h +++ b/include/libbb.h @@ -185,24 +185,32 @@ int klogctl(int type, char *b, int len); /* Busybox does not use threads, we can speed up stdio. */ #ifdef HAVE_UNLOCKED_STDIO # undef getc -# define getc(stream) getc_unlocked(stream) +# define getc(stream) getc_unlocked(stream) # undef getchar -# define getchar() getchar_unlocked() +# define getchar() getchar_unlocked() # undef putc -# define putc(c, stream) putc_unlocked(c, stream) +# define putc(c,stream) putc_unlocked(c,stream) # undef putchar -# define putchar(c) putchar_unlocked(c) +# define putchar(c) putchar_unlocked(c) # undef fgetc -# define fgetc(stream) getc_unlocked(stream) +# define fgetc(stream) getc_unlocked(stream) # undef fputc -# define fputc(c, stream) putc_unlocked(c, stream) +# define fputc(c,stream) putc_unlocked(c,stream) #endif /* Above functions are required by POSIX.1-2008, below ones are extensions */ #ifdef HAVE_UNLOCKED_LINE_OPS # undef fgets -# define fgets(s, n, stream) fgets_unlocked(s, n, stream) +# define fgets(s,n,stream) fgets_unlocked(s,n,stream) # undef fputs -# define fputs(s, stream) fputs_unlocked(s, stream) +# define fputs(s,stream) fputs_unlocked(s,stream) +# undef fflush +# define fflush(stream) fflush_unlocked(stream) +# undef feof +# define feof(stream) feof_unlocked(stream) +# undef ferror +# define ferror(stream) ferror_unlocked(stream) +# undef fileno +# define fileno(stream) fileno_unlocked(stream) #endif diff --git a/shell/hush.c b/shell/hush.c index 6b0d850..a8ec54e 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -103,6 +103,9 @@ #else # define CLEAR_RANDOM_T(rnd) ((void)0) #endif +#ifndef F_DUPFD_CLOEXEC +# define F_DUPFD_CLOEXEC F_DUPFD +#endif #ifndef PIPE_BUF # define PIPE_BUF 4096 /* amount of buffering in a pipe */ #endif @@ -711,10 +714,10 @@ enum { }; -/* Can be extended to handle a FIXME in setup_redirects about not saving script fds */ struct FILE_list { struct FILE_list *next; FILE *fp; + int fd; }; @@ -809,9 +812,7 @@ struct globals { unsigned handled_SIGCHLD; smallint we_have_children; #endif -#if ENABLE_FEATURE_SH_STANDALONE struct FILE_list *FILE_list; -#endif /* Which signals have non-DFL handler (even with no traps set)? * Set at the start to: * (SIGQUIT + maybe SPECIAL_INTERACTIVE_SIGS + maybe SPECIAL_JOBSTOP_SIGS) @@ -1262,35 +1263,34 @@ static void free_strings(char **strings) } +static int xdup_and_close(int fd, int F_DUPFD_maybe_CLOEXEC) +{ + /* We avoid taking stdio fds. Mimicking ash: use fds above 9 */ + int newfd = fcntl(fd, F_DUPFD_maybe_CLOEXEC, 10); + if (newfd < 0) { + /* fd was not open? */ + if (errno == EBADF) + return fd; + xfunc_die(); + } + close(fd); + return newfd; +} + + /* Manipulating the list of open FILEs */ static FILE *remember_FILE(FILE *fp) { if (fp) { -#if ENABLE_FEATURE_SH_STANDALONE struct FILE_list *n = xmalloc(sizeof(*n)); - n->fp = fp; n->next = G.FILE_list; G.FILE_list = n; -#endif - close_on_exec_on(fileno(fp)); + n->fp = fp; + n->fd = fileno(fp); + close_on_exec_on(n->fd); } return fp; } -#if ENABLE_FEATURE_SH_STANDALONE -static void close_all_FILE_list(void) -{ - struct FILE_list *fl = G.FILE_list; - while (fl) { - /* fclose would also free FILE object. - * It is disastrous if we share memory with a vforked parent. - * I'm not sure we never come here after vfork. - * Therefore just close fd, nothing more. - */ - /*fclose(fl->fp); - unsafe */ - close(fileno(fl->fp)); - fl = fl->next; - } -} static void fclose_and_forget(FILE *fp) { struct FILE_list **pp = &G.FILE_list; @@ -1305,8 +1305,46 @@ static void fclose_and_forget(FILE *fp) } fclose(fp); } -#else -# define fclose_and_forget(fp) fclose(fp); +static int save_FILEs_on_redirect(int fd) +{ + struct FILE_list *fl = G.FILE_list; + while (fl) { + if (fd == fl->fd) { + /* We use it only on script files, they are all CLOEXEC */ + fl->fd = xdup_and_close(fd, F_DUPFD_CLOEXEC); + return 1; + } + fl = fl->next; + } + return 0; +} +static void restore_redirected_FILEs(void) +{ + struct FILE_list *fl = G.FILE_list; + while (fl) { + int should_be = fileno(fl->fp); + if (fl->fd != should_be) { + xmove_fd(fl->fd, should_be); + fl->fd = should_be; + } + fl = fl->next; + } +} +#if ENABLE_FEATURE_SH_STANDALONE +static void close_all_FILE_list(void) +{ + struct FILE_list *fl = G.FILE_list; + while (fl) { + /* fclose would also free FILE object. + * It is disastrous if we share memory with a vforked parent. + * I'm not sure we never come here after vfork. + * Therefore just close fd, nothing more. + */ + /*fclose(fl->fp); - unsafe */ + close(fl->fd); + fl = fl->next; + } +} #endif @@ -6147,6 +6185,74 @@ static void setup_heredoc(struct redir_struct *redir) wait(NULL); /* wait till child has died */ } +/* fd: redirect wants this fd to be used (e.g. 3>file). + * Move all conflicting internally used fds, + * and remember them so that we can restore them later. + */ +static int save_fds_on_redirect(int fd, int squirrel[3]) +{ + if (squirrel) { + /* Handle redirects of fds 0,1,2 */ + + /* If we collide with an already moved stdio fd... */ + if (fd == squirrel[0]) { + squirrel[0] = xdup_and_close(squirrel[0], F_DUPFD); + return 1; + } + if (fd == squirrel[1]) { + squirrel[1] = xdup_and_close(squirrel[1], F_DUPFD); + return 1; + } + if (fd == squirrel[2]) { + squirrel[2] = xdup_and_close(squirrel[2], F_DUPFD); + return 1; + } + /* If we are about to redirect stdio fd, and did not yet move it... */ + if (fd <= 2 && squirrel[fd] < 0) { + /* We avoid taking stdio fds */ + squirrel[fd] = fcntl(fd, F_DUPFD, 10); + if (squirrel[fd] < 0 && errno != EBADF) + xfunc_die(); + return 0; /* "we did not close fd" */ + } + } + +#if ENABLE_HUSH_INTERACTIVE + if (fd != 0 && fd == G.interactive_fd) { + G.interactive_fd = xdup_and_close(G.interactive_fd, F_DUPFD_CLOEXEC); + return 1; + } +#endif + + /* Are we called from setup_redirects(squirrel==NULL)? Two cases: + * (1) Redirect in a forked child. No need to save FILEs' fds, + * we aren't going to use them anymore, ok to trash. + * (2) "exec 3>FILE". Bummer. We can save FILEs' fds, + * but how are we doing to use them? + * "fileno(fd) = new_fd" can't be done. + */ + if (!squirrel) + return 0; + + return save_FILEs_on_redirect(fd); +} + +static void restore_redirects(int squirrel[3]) +{ + int i, fd; + for (i = 0; i <= 2; i++) { + fd = squirrel[i]; + if (fd != -1) { + /* We simply die on error */ + xmove_fd(fd, i); + } + } + + /* Moved G.interactive_fd stays on new fd, not doing anything for it */ + + restore_redirected_FILEs(); +} + /* squirrel != NULL means we squirrel away copies of stdin, stdout, * and stderr if they are redirected. */ static int setup_redirects(struct command *prog, int squirrel[]) @@ -6157,13 +6263,7 @@ static int setup_redirects(struct command *prog, int squirrel[]) for (redir = prog->redirects; redir; redir = redir->next) { if (redir->rd_type == REDIRECT_HEREDOC2) { /* "rd_fd<<HERE" case */ - if (redir->rd_fd <= 2 - && squirrel - && squirrel[redir->rd_fd] < 0 - ) { - /* Save old fds 0..2 if redirect uses them */ - squirrel[redir->rd_fd] = dup(redir->rd_fd); - } + save_fds_on_redirect(redir->rd_fd, squirrel); /* for REDIRECT_HEREDOC2, rd_filename holds _contents_ * of the heredoc */ debug_printf_parse("set heredoc '%s'\n", @@ -6199,47 +6299,26 @@ static int setup_redirects(struct command *prog, int squirrel[]) } if (openfd != redir->rd_fd) { - if (redir->rd_fd <= 2 - && squirrel - && squirrel[redir->rd_fd] < 0 - ) { - /* Save old fds 0..2 if redirect uses them */ -//FIXME: script fd's also need this! "sh SCRIPT" and SCRIPT has "echo FOO 3>&-": -// open("SCRIPT", O_RDONLY) = 3 -// fcntl(3, F_SETFD, FD_CLOEXEC) = 0 -// read(3, "echo FOO 3>&-\n....", 4096) = N -// close(3) = 0 -// write(1, "FOO\n", 4) = 4 -// ... -// read(3, 0x205f8e0, 4096) = -1 EBADF <== BUG -// - squirrel[redir->rd_fd] = dup(redir->rd_fd); - } + int closed = save_fds_on_redirect(redir->rd_fd, squirrel); if (openfd == REDIRFD_CLOSE) { - /* "n>-" means "close me" */ - close(redir->rd_fd); + /* "rd_fd >&-" means "close me" */ + if (!closed) { + /* ^^^ optimization: saving may already + * have closed it. If not... */ + close(redir->rd_fd); + } } else { xdup2(openfd, redir->rd_fd); if (redir->rd_dup == REDIRFD_TO_FILE) + /* "rd_fd > FILE" */ close(openfd); + /* else: "rd_fd > rd_dup" */ } } } return 0; } -static void restore_redirects(int squirrel[]) -{ - int i, fd; - for (i = 0; i <= 2; i++) { - fd = squirrel[i]; - if (fd != -1) { - /* We simply die on error */ - xmove_fd(fd, i); - } - } -} - static char *find_in_path(const char *arg) { char *ret = NULL; diff --git a/shell/hush_test/hush-misc/redir_script.right b/shell/hush_test/hush-misc/redir_script.right new file mode 100644 index 0000000..6694ed3 --- /dev/null +++ b/shell/hush_test/hush-misc/redir_script.right @@ -0,0 +1 @@ +Ok: script fd is not closed diff --git a/shell/hush_test/hush-misc/redir_script.tests b/shell/hush_test/hush-misc/redir_script.tests new file mode 100755 index 0000000..ccc497d --- /dev/null +++ b/shell/hush_test/hush-misc/redir_script.tests @@ -0,0 +1,29 @@ +# Builds a " 3>&- 4>&-" string. +# Note: one of these fds is a directory opened to /proc/self/fd +# for globbing. It is unwanted, but I don't know how to filter it out. +find_fds() { + fds="" + for f in /proc/self/fd/*; do + test "$f" = "/proc/self/fd/0" && continue + test "$f" = "/proc/self/fd/1" && continue + test "$f" = "/proc/self/fd/2" && continue + fds="$fds ${f##*/}>&-" + done +} + +find_fds +fds1="$fds" + +# One of the fds is open to the script body +# Close it while executing something. +eval "find_fds $fds" + +# Shell should not lose that fd. Did it? +find_fds +test x"$fds1" = x"$fds" && { echo "Ok: script fd is not closed"; exit 0; } + +echo "Bug: script fd is closed" +echo "fds1:$fds1" +echo "fds2:$fds" +exit 1 + |