| /* |
| * Copyright (c) 2013 The Chromium OS Authors. All rights reserved. |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <limits.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/stat.h> |
| #include <unistd.h> |
| |
| #include "futility.h" |
| |
| #define MYNAME "futility" |
| #ifdef OLDDIR |
| #define XSTR(A) STR(A) |
| #define STR(A) #A |
| #define SUBDIR XSTR(OLDDIR) |
| #else |
| #define SUBDIR "old_bins" |
| #endif |
| |
| /* File to use for logging, if present */ |
| #define LOGFILE "/tmp/futility.log" |
| |
| /* Normally logging will only happen if the logfile already exists. Uncomment |
| * this to force log file creation (and thus logging) always. */ |
| /* #define FORCE_LOGGING_ON */ |
| |
| /******************************************************************************/ |
| |
| static const char * const usage= "\n\ |
| Usage: " MYNAME " PROGRAM|COMMAND [args...]\n\ |
| \n\ |
| This is the unified firmware utility, which will eventually replace\n\ |
| all the distinct userspace tools formerly produced by the\n\ |
| vboot_reference package.\n\ |
| \n\ |
| When symlinked under the name of one of those previous tools, it can\n\ |
| do one of two things: either it will fully implement the original\n\ |
| behavior, or (until that functionality is complete) it will just exec\n\ |
| the original binary.\n\ |
| \n\ |
| In either case it can append some usage information to " LOGFILE "\n\ |
| to help improve coverage and correctness.\n\ |
| \n\ |
| If you invoke it directly instead of via a symlink, it requires one\n\ |
| argument, which is the name of the old binary to exec. That binary\n\ |
| must be located in a directory named \"" SUBDIR "\" underneath\n\ |
| the " MYNAME " executable.\n\ |
| \n"; |
| |
| static int help(int argc, char *argv[]) |
| { |
| futil_cmd_t *cmd; |
| int i; |
| |
| fputs(usage, stdout); |
| |
| printf("The following commands are built-in:\n"); |
| |
| for (cmd = futil_cmds_start(); cmd < futil_cmds_end(); cmd++) |
| printf(" %-20s %s\n", |
| cmd->name, cmd->shorthelp); |
| |
| printf("\n"); |
| |
| printf("FYI, you added these args that I'm ignoring:\n"); |
| for (i = 0; i < argc; i++) |
| printf("argv[%d] = %s\n", i, argv[i]); |
| |
| return 0; |
| } |
| DECLARE_FUTIL_COMMAND(help, help, "Show a bit of help"); |
| |
| |
| /******************************************************************************/ |
| /* Logging stuff */ |
| |
| static int log_fd = -1; |
| |
| /* Write the string and a newline. Silently give up on errors */ |
| static void log_str(char *str) |
| { |
| int len, done, n; |
| |
| if (log_fd < 0) |
| return; |
| |
| if (!str) |
| str = "(NULL)"; |
| |
| len = strlen(str); |
| if (len == 0) { |
| str = "(EMPTY)"; |
| len = strlen(str); |
| } |
| |
| for (done = 0; done < len; done += n) { |
| n = write(log_fd, str + done, len - done); |
| if (n < 0) |
| return; |
| } |
| |
| write(log_fd, "\n", 1); |
| } |
| |
| static void log_close(void) |
| { |
| struct flock lock; |
| |
| if (log_fd >= 0) { |
| memset(&lock, 0, sizeof(lock)); |
| lock.l_type = F_UNLCK; |
| lock.l_whence = SEEK_SET; |
| if (fcntl(log_fd, F_SETLKW, &lock)) |
| perror("Unable to unlock log file"); |
| |
| close(log_fd); |
| log_fd = -1; |
| } |
| } |
| |
| static void log_open(void) |
| { |
| struct flock lock; |
| int ret; |
| |
| #ifdef FORCE_LOGGING_ON |
| log_fd = open(LOGFILE, O_WRONLY|O_APPEND|O_CREAT, 0666); |
| #else |
| log_fd = open(LOGFILE, O_WRONLY|O_APPEND); |
| #endif |
| if (log_fd < 0) { |
| |
| if (errno != EACCES) |
| return; |
| |
| /* Permission problems should improve shortly ... */ |
| sleep(1); |
| log_fd = open(LOGFILE, O_WRONLY|O_APPEND|O_CREAT, 0666); |
| if (log_fd < 0) /* Nope, they didn't */ |
| return; |
| } |
| |
| /* Let anyone have a turn */ |
| fchmod(log_fd, 0666); |
| |
| /* But only one at a time */ |
| memset(&lock, 0, sizeof(lock)); |
| lock.l_type = F_WRLCK; |
| lock.l_whence = SEEK_END; |
| |
| ret = fcntl(log_fd, F_SETLKW, &lock); /* this blocks */ |
| if (ret < 0) |
| log_close(); |
| } |
| |
| #define CALLER_PREFIX "CALLER:" |
| static void log_args(int argc, char *argv[]) |
| { |
| int i; |
| ssize_t r; |
| pid_t parent; |
| char buf[80]; |
| char str_caller[PATH_MAX + sizeof(CALLER_PREFIX)] = CALLER_PREFIX; |
| char *truename = str_caller + sizeof(CALLER_PREFIX) - 1; |
| /* Note: truename starts on the \0 from CALLER_PREFIX, so we can write |
| * PATH_MAX chars into truename and still append a \0 at the end. */ |
| |
| log_open(); |
| |
| /* delimiter */ |
| log_str("##### HEY #####"); |
| |
| /* Can we tell who called us? */ |
| parent = getppid(); |
| snprintf(buf, sizeof(buf), "/proc/%d/exe", parent); |
| r = readlink(buf, truename, PATH_MAX); |
| if (r >= 0) { |
| truename[r] = '\0'; |
| log_str(str_caller); |
| } |
| |
| /* Now log the stuff about ourselves */ |
| for (i = 0; i < argc; i++) |
| log_str(argv[i]); |
| |
| log_close(); |
| } |
| |
| |
| /******************************************************************************/ |
| /* Here we go */ |
| |
| int main(int argc, char *argv[], char *envp[]) |
| { |
| char *progname; |
| char truename[PATH_MAX]; |
| char oldname[PATH_MAX]; |
| char buf[80]; |
| pid_t myproc; |
| ssize_t r; |
| char *s; |
| futil_cmd_t *cmd; |
| |
| log_args(argc, argv); |
| |
| /* How were we invoked? */ |
| progname = strrchr(argv[0], '/'); |
| if (progname) |
| progname++; |
| else |
| progname = argv[0]; |
| |
| /* Invoked directly by name */ |
| if (0 == strcmp(progname, MYNAME)) { |
| if (argc < 2) { /* must have an argument */ |
| fputs(usage, stderr); |
| exit(1); |
| } |
| |
| /* We can just pass the rest along, then */ |
| argc--; |
| argv++; |
| |
| /* So now what name do we want to invoke? */ |
| progname = strrchr(argv[0], '/'); |
| if (progname) |
| progname++; |
| else |
| progname = argv[0]; |
| } |
| |
| /* See if it's asking for something we know how to do ourselves */ |
| for (cmd = futil_cmds_start(); cmd < futil_cmds_end(); cmd++) |
| if (0 == strcmp(cmd->name, progname)) |
| return cmd->handler(argc, argv); |
| |
| /* Nope, it must be wrapped */ |
| |
| /* The old binaries live under the true executable. Find out where that is. */ |
| myproc = getpid(); |
| snprintf(buf, sizeof(buf), "/proc/%d/exe", myproc); |
| r = readlink(buf, truename, PATH_MAX - 1); |
| if (r < 0) { |
| fprintf(stderr, "%s is lost: %s => %s: %s\n", MYNAME, argv[0], |
| buf, strerror(errno)); |
| exit(1); |
| } else if (r == PATH_MAX - 1) { |
| /* Yes, it might _just_ fit, but we'll count that as wrong anyway. We can't |
| * determine the right size using the example in the readlink manpage, |
| * because the /proc symlink returns an st_size of 0. */ |
| fprintf(stderr, "%s is too long: %s => %s\n", MYNAME, argv[0], buf); |
| exit(1); |
| } |
| |
| truename[r] = '\0'; |
| s = strrchr(truename, '/'); /* Find the true directory */ |
| if (s) { |
| *s = '\0'; |
| } else { /* I don't think this can happen */ |
| fprintf(stderr, "%s says %s doesn't make sense\n", MYNAME, truename); |
| exit(1); |
| } |
| /* If the old binary path doesn't fit, just give up. */ |
| r = snprintf(oldname, PATH_MAX, "%s/%s/%s", truename, SUBDIR, progname); |
| if (r >= PATH_MAX) { |
| fprintf(stderr, "%s/%s/%s is too long\n", truename, SUBDIR, progname); |
| exit(1); |
| } |
| |
| fflush(0); |
| execve(oldname, argv, envp); |
| |
| fprintf(stderr, "%s failed to exec %s: %s\n", MYNAME, |
| oldname, strerror(errno)); |
| return 1; |
| } |