util/cbfstool/flashrom.c

   1 /* Copyright 2020 The ChromiumOS Authors. All rights reserved.
   2  * Use of this source code is governed by a BSD-style license that can be
   3  * found in the LICENSE file.
   4  */
   5
   6 /* For strdup */
   7 #define _POSIX_C_SOURCE 200809L
   8 #include <fcntl.h>
   9 #include <limits.h>
  10 #include <stdbool.h>
  11 #include <stdint.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/stat.h>
  16 #include <sys/types.h>
  17 #include <unistd.h>
  18
  19 #include "common.h" /* from cbfstool for buffer API. */
  20 #include "subprocess.h" /* from vboot_reference */
  21 #include "flashrom.h"
  22
  23 #define FLASHROM_EXEC_NAME "flashrom"
  24 #define FLASHROM_PROGRAMMER_INTERNAL_AP "internal"
  25
  26 /**
  27  * Helper to create a temporary file.
  28  *
  29  * @param path_out      An output pointer for the filename. Caller should free.
  30  *
  31  * @return 0 on success, -1 for file open error, or -2 for write error.
  32  */
  33 static int create_temp_file(char **path_out)
  34 {
  35         int fd;
  36         int rv;
  37         char *path;
  38         mode_t umask_save;
  39
  40 #if defined(__FreeBSD__)
  41 #define P_tmpdir "/tmp"
  42 #endif
  43         *path_out = NULL;
  44         path = strdup(P_tmpdir "/flashrom.XXXXXX");
  45         /* Set the umask before mkstemp for security considerations. */
  46         umask_save = umask(077);
  47         fd = mkstemp(path);
  48         umask(umask_save);
  49         if (fd < 0) {
  50                 rv = -1;
  51                 goto fail;
  52         }
  53
  54         close(fd);
  55         *path_out = path;
  56
  57         return 0;
  58 fail:
  59         free(path);
  60         return rv;
  61 }
  62
  63 static int run_flashrom(const char *const argv[])
  64 {
  65         int status = subprocess_run(argv, &subprocess_null, &subprocess_null,
  66                                     &subprocess_null);
  67         if (status) {
  68                 fprintf(stderr, "Flashrom invocation failed (exit status %d):",
  69                         status);
  70                 for (const char *const *argp = argv; *argp; argp++)
  71                         fprintf(stderr, " %s", *argp);
  72                 fprintf(stderr, "\n");
  73                 return -1;
  74         }
  75
  76         return 0;
  77 }
  78
  79 int flashrom_host_read(struct buffer *buffer, const char *region)
  80 {
  81         char *tmpfile;
  82         char region_param[PATH_MAX];
  83         int rv;
  84
  85         if (create_temp_file(&tmpfile) != 0)
  86                 return -1;
  87         if (region)
  88                 snprintf(region_param, sizeof(region_param), "%s:%s", region,
  89                          tmpfile);
  90         const char *const argv[] = {
  91                 FLASHROM_EXEC_NAME,
  92                 "-p",
  93                 FLASHROM_PROGRAMMER_INTERNAL_AP,
  94                 "-r",
  95                 region ? "-i" : tmpfile,
  96                 region ? region_param : NULL,
  97                 NULL,
  98         };
  99         rv = run_flashrom(argv);
 100         if (!rv)
 101                 rv = buffer_from_file(buffer, tmpfile);
 102
 103         unlink(tmpfile);
 104         free(tmpfile);
 105
 106         return rv;
 107 }
 108
 109 int flashrom_host_write(struct buffer *buffer, const char *region)
 110 {
 111         char *tmpfile;
 112         char region_param[PATH_MAX];
 113         int rv;
 114
 115         if (create_temp_file(&tmpfile) != 0)
 116                 return -1;
 117         if (buffer_write_file(buffer, tmpfile) != 0) {
 118                 rv = -2;
 119                 goto fail;
 120         }
 121
 122         if (region)
 123                 snprintf(region_param, sizeof(region_param), "%s:%s", region,
 124                          tmpfile);
 125         const char *const argv[] = {
 126                 FLASHROM_EXEC_NAME,
 127                 "-p",
 128                 FLASHROM_PROGRAMMER_INTERNAL_AP,
 129                 "--noverify-all",
 130                 "-w",
 131                 region ? "-i" : tmpfile,
 132                 region ? region_param : NULL,
 133                 NULL,
 134         };
 135
 136         rv = run_flashrom(argv);
 137
 138 fail:
 139         unlink(tmpfile);
 140         free(tmpfile);
 141
 142         return rv;
 143 }