diff options
| -rw-r--r-- | exec/hashexec.c | 135 |
1 files changed, 53 insertions, 82 deletions
diff --git a/exec/hashexec.c b/exec/hashexec.c index bd617124..6eff8015 100644 --- a/exec/hashexec.c +++ b/exec/hashexec.c @@ -1,5 +1,5 @@ /* GNU Hurd standard exec server, #! script execution support. - Copyright (C) 1995 Free Software Foundation, Inc. + Copyright (C) 1995, 1996 Free Software Foundation, Inc. Written by Roland McGrath. This file is part of the GNU Hurd. @@ -20,7 +20,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "priv.h" -#include <hurd/signal.h> +#include <hurd/sigpreempt.h> #include <unistd.h> /* This is called to check E for a #! interpreter specification. E has @@ -164,21 +164,17 @@ check_hashbang (struct execdata *e, if (! e->error) { - /* This code is in a local function here for convenience. Some things in - this function need to be protected against faults while accessing ARGV - and ENVP; below, we register to preempt signals on these fault areas - before calling prepare_args, and unregister afterwards. When such a - fault is detected, the handler does `longjmp (args_faulted, 1)'. */ - jmp_buf args_faulted; - - inline void prepare_args (void) + void fault_handler (int signo) + { longjmp (args_faulted, 1); } + error_t setup_args (struct hurd_signal_preempter *preempter) { - char *file_name = NULL; size_t namelen; - if (! (flags & EXEC_SECURE)) + if (setjmp (args_faulted)) + file_name = NULL; + else if (! (flags & EXEC_SECURE)) { /* Try to figure out the file's name. We guess that if ARGV[0] contains a slash, it might be the name of the file; and that @@ -193,29 +189,12 @@ check_hashbang (struct execdata *e, fsid_t file_fsid; ino_t file_fileno; - error = io_stat (file, &st); /* XXX insecure */ - if (error) - goto out; - file_fstype = st.st_fstype; - file_fsid = st.st_fsid; - file_fileno = st.st_ino; - - if (memchr (argv, '\0', argvlen) == NULL) + /* Search $PATH for NAME, opening a port NAME_FILE on it. + This is encapsulated in a function so we can catch faults + reading the user's environment. */ + error_t search_path (struct hurd_signal_preempter *preempter) { - name = alloca (argvlen + 1); - bcopy (argv, name, argvlen); - name[argvlen] = '\0'; - } - else - name = argv; - - if (strchr (name, '/') != NULL) - error = lookup (name, 0, &name_file); - else if (! setjmp (args_faulted)) - { - /* Search PATH for it. If we fault accessing ENVP, setjmp - will return again, nonzero this time, and we give up. */ - + error_t error; const char envar[] = "\0PATH="; char *path, *p; if (envplen >= sizeof (envar) && @@ -270,8 +249,32 @@ check_hashbang (struct execdata *e, break; } } while ((p = path) != NULL); + + return p ? error : ENOENT; + } + + error = io_stat (file, &st); /* XXX insecure */ + if (error) + goto out; + file_fstype = st.st_fstype; + file_fsid = st.st_fsid; + file_fileno = st.st_ino; + + if (memchr (argv, '\0', argvlen) == NULL) + { + name = alloca (argvlen + 1); + bcopy (argv, name, argvlen); + name[argvlen] = '\0'; } else + name = argv; + + if (strchr (name, '/') != NULL) + error = lookup (name, 0, &name_file); + else if ((error = hurd_catch_signal + (sigmask (SIGBUS) | sigmask (SIGSEGV), + (vm_address_t) envp, (vm_address_t) envp + envplen, + &search_path, SIG_ERR))) name_file = MACH_PORT_NULL; if (!error && name_file != MACH_PORT_NULL) @@ -319,16 +322,16 @@ check_hashbang (struct execdata *e, namelen = strlen (file_name) + 1; + new_argvlen = argvlen + len + namelen; + e->error = vm_allocate (mach_task_self (), + (vm_address_t *) &new_argv, + new_argvlen, 1); + if (e->error) + return e->error; + if (! setjmp (args_faulted)) { - /* XXX leaks below if fault */ char *other_args; - new_argvlen = argvlen + len + namelen; - e->error = vm_allocate (mach_task_self (), - (vm_address_t *) &new_argv, - new_argvlen, 1); - if (e->error) - return; other_args = memccpy (new_argv, argv, '\0', argvlen); p = &new_argv[other_args ? other_args - new_argv : argvlen]; if (arg) @@ -345,51 +348,19 @@ check_hashbang (struct execdata *e, else { /* We got a fault reading ARGV. So don't use it. */ - static const char loser[] - = "**fault in exec server reading argv[0]**"; - new_argvlen = sizeof (loser) + len + namelen; - new_argv = alloca (argvlen); - memcpy (new_argv, loser, sizeof (loser)); - memcpy (new_argv + sizeof (loser), arg, len); - memcpy (new_argv + sizeof (loser) + len, file_name, namelen); + char *n = stpncpy (new_argv, + "**fault in exec server reading argv[0]**", + argvlen); + memcpy (memcpy (n, arg, len) + len, file_name, namelen); } - } - - /* Preempt SIGSEGV signals for the address ranges of ARGV and ENVP. - When such a signal arrives, `preempter' is called to decide what - handler to run; it always returns `handler', which is then invoked - as a normal signal handler. Our handler always simply longjmps to - ARGS_FAULTED. */ - void handler (int sig) - { - longjmp (args_faulted, 1); - } - const thread_t mythread = hurd_thread_self (); - sighandler_t preempter (thread_t thread, - int signo, long int sigcode, int sigerror) - { - return thread == mythread ? handler : SIG_DFL; + return 0; } - struct hurd_signal_preempt argv_preempter, envp_preempter; - - /* Register the preemptions. */ - hurd_preempt_signals (&argv_preempter, SIGSEGV, - (long int) argv, (long int) argv + argvlen - 1, - preempter); - hurd_preempt_signals (&envp_preempter, SIGSEGV, - (long int) envp, (long int) envp + envplen - 1, - preempter); - - /* Do the work. Everywhere we might get a page fault inside ARGV or - ENVP, is inside the zero-return case of an `if' on setjmp - (ARGS_FAULTED). */ - prepare_args (); - - /* Unregister the preemptions. */ - hurd_unpreempt_signals (&argv_preempter, SIGSEGV); - hurd_unpreempt_signals (&envp_preempter, SIGSEGV); + /* Set up the arguments. */ + hurd_catch_signal (sigmask (SIGSEGV) | sigmask (SIGBUS), + (vm_address_t) argv, (vm_address_t) argv + argvlen, + &setup_args, &fault_handler); } /* We are now done reading the script file. */ |