diff options
| -rw-r--r-- | arch/um/include/os.h | 2 | ||||
| -rw-r--r-- | arch/um/os-Linux/Makefile | 10 | ||||
| -rw-r--r-- | arch/um/os-Linux/execvp.c | 149 | ||||
| -rw-r--r-- | arch/um/os-Linux/helper.c | 14 |
4 files changed, 166 insertions, 9 deletions
diff --git a/arch/um/include/os.h b/arch/um/include/os.h index 6516f6dca96d..13a86bd383d3 100644 --- a/arch/um/include/os.h +++ b/arch/um/include/os.h @@ -233,6 +233,8 @@ extern unsigned long __do_user_copy(void *to, const void *from, int n, void (*op)(void *to, const void *from, int n), int *faulted_out); +/* execvp.c */ +extern int execvp_noalloc(char *buf, const char *file, char *const argv[]); /* helper.c */ extern int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv, unsigned long *stack_out); diff --git a/arch/um/os-Linux/Makefile b/arch/um/os-Linux/Makefile index b4183929b32c..2f8c79464015 100644 --- a/arch/um/os-Linux/Makefile +++ b/arch/um/os-Linux/Makefile @@ -3,8 +3,8 @@ # Licensed under the GPL # -obj-y = aio.o elf_aux.o file.o helper.o irq.o main.o mem.o process.o sigio.o \ - signal.o start_up.o time.o trap.o tty.o uaccess.o umid.o tls.o \ +obj-y = aio.o elf_aux.o execvp.o file.o helper.o irq.o main.o mem.o process.o \ + sigio.o signal.o start_up.o time.o trap.o tty.o uaccess.o umid.o tls.o \ user_syms.o util.o drivers/ sys-$(SUBARCH)/ obj-$(CONFIG_MODE_SKAS) += skas/ @@ -15,9 +15,9 @@ user-objs-$(CONFIG_MODE_TT) += tt.o obj-$(CONFIG_TTY_LOG) += tty_log.o user-objs-$(CONFIG_TTY_LOG) += tty_log.o -USER_OBJS := $(user-objs-y) aio.o elf_aux.o file.o helper.o irq.o main.o mem.o \ - process.o sigio.o signal.o start_up.o time.o trap.o tty.o tls.o \ - uaccess.o umid.o util.o +USER_OBJS := $(user-objs-y) aio.o elf_aux.o execvp.o file.o helper.o irq.o \ + main.o mem.o process.o sigio.o signal.o start_up.o time.o trap.o tty.o \ + tls.o uaccess.o umid.o util.o CFLAGS_user_syms.o += -DSUBARCH_$(SUBARCH) diff --git a/arch/um/os-Linux/execvp.c b/arch/um/os-Linux/execvp.c new file mode 100644 index 000000000000..66e583a4031b --- /dev/null +++ b/arch/um/os-Linux/execvp.c @@ -0,0 +1,149 @@ +/* Copyright (C) 2006 by Paolo Giarrusso - modified from glibc' execvp.c. + Original copyright notice follows: + + Copyright (C) 1991,92,1995-99,2002,2004 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ +#include <unistd.h> + +#include <stdbool.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <limits.h> + +#ifndef TEST +#include "um_malloc.h" +#else +#include <stdio.h> +#define um_kmalloc malloc +#endif +#include "os.h" + +/* Execute FILE, searching in the `PATH' environment variable if it contains + no slashes, with arguments ARGV and environment from `environ'. */ +int execvp_noalloc(char *buf, const char *file, char *const argv[]) +{ + if (*file == '\0') { + return -ENOENT; + } + + if (strchr (file, '/') != NULL) { + /* Don't search when it contains a slash. */ + execv(file, argv); + } else { + int got_eacces; + size_t len, pathlen; + char *name, *p; + char *path = getenv("PATH"); + if (path == NULL) + path = ":/bin:/usr/bin"; + + len = strlen(file) + 1; + pathlen = strlen(path); + /* Copy the file name at the top. */ + name = memcpy(buf + pathlen + 1, file, len); + /* And add the slash. */ + *--name = '/'; + + got_eacces = 0; + p = path; + do { + char *startp; + + path = p; + //Let's avoid this GNU extension. + //p = strchrnul (path, ':'); + p = strchr(path, ':'); + if (!p) + p = strchr(path, '\0'); + + if (p == path) + /* Two adjacent colons, or a colon at the beginning or the end + of `PATH' means to search the current directory. */ + startp = name + 1; + else + startp = memcpy(name - (p - path), path, p - path); + + /* Try to execute this name. If it works, execv will not return. */ + execv(startp, argv); + + /* + if (errno == ENOEXEC) { + } + */ + + switch (errno) { + case EACCES: + /* Record the we got a `Permission denied' error. If we end + up finding no executable we can use, we want to diagnose + that we did find one but were denied access. */ + got_eacces = 1; + case ENOENT: + case ESTALE: + case ENOTDIR: + /* Those errors indicate the file is missing or not executable + by us, in which case we want to just try the next path + directory. */ + case ENODEV: + case ETIMEDOUT: + /* Some strange filesystems like AFS return even + stranger error numbers. They cannot reasonably mean + anything else so ignore those, too. */ + case ENOEXEC: + /* We won't go searching for the shell + * if it is not executable - the Linux + * kernel already handles this enough, + * for us. */ + break; + + default: + /* Some other error means we found an executable file, but + something went wrong executing it; return the error to our + caller. */ + return -errno; + } + } while (*p++ != '\0'); + + /* We tried every element and none of them worked. */ + if (got_eacces) + /* At least one failure was due to permissions, so report that + error. */ + return -EACCES; + } + + /* Return the error from the last attempt (probably ENOENT). */ + return -errno; +} +#ifdef TEST +int main(int argc, char**argv) +{ + char buf[PATH_MAX]; + int ret; + argc--; + if (!argc) { + fprintf(stderr, "Not enough arguments\n"); + return 1; + } + argv++; + if (ret = execvp_noalloc(buf, argv[0], argv)) { + errno = -ret; + perror("execvp_noalloc"); + } + return 0; +} +#endif diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c index d13299cfa318..c7ad6306e22f 100644 --- a/arch/um/os-Linux/helper.c +++ b/arch/um/os-Linux/helper.c @@ -8,18 +8,21 @@ #include <unistd.h> #include <errno.h> #include <sched.h> +#include <limits.h> #include <sys/signal.h> #include <sys/wait.h> #include "user.h" #include "kern_util.h" #include "user_util.h" #include "os.h" +#include "um_malloc.h" struct helper_data { void (*pre_exec)(void*); void *pre_data; char **argv; int fd; + char *buf; }; /* Debugging aid, changed only from gdb */ @@ -41,9 +44,8 @@ static int helper_child(void *arg) } if (data->pre_exec != NULL) (*data->pre_exec)(data->pre_data); - execvp(argv[0], argv); - errval = -errno; - printk("helper_child - execve of '%s' failed - errno = %d\n", argv[0], errno); + errval = execvp_noalloc(data->buf, argv[0], argv); + printk("helper_child - execvp of '%s' failed - errno = %d\n", argv[0], -errval); os_write_file(data->fd, &errval, sizeof(errval)); kill(os_getpid(), SIGKILL); return 0; @@ -84,11 +86,13 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv, data.pre_data = pre_data; data.argv = argv; data.fd = fds[1]; + data.buf = __cant_sleep() ? um_kmalloc_atomic(PATH_MAX) : + um_kmalloc(PATH_MAX); pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data); if (pid < 0) { ret = -errno; printk("run_helper : clone failed, errno = %d\n", errno); - goto out_close; + goto out_free2; } close(fds[1]); @@ -109,6 +113,8 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv, CATCH_EINTR(waitpid(pid, NULL, 0)); } +out_free2: + kfree(data.buf); out_close: if (fds[1] != -1) close(fds[1]); |