util/nvmutil: General code cleanup
A lot of size-coding was performed in prior audits, to make the sloccount lower on nvmutil, but this resulted in code that wasn't very human readable. I've reversed some of it and added comments, for clarity. Signed-off-by: Leah Rowe <leah@libreboot.org>master
parent
232f6b8610
commit
fe55e33254
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@ -28,12 +28,13 @@ uint8_t hextonum(char chs), rhex(void);
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uint16_t buf16[SIZE_4KB], mac[3] = {0, 0, 0};
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uint8_t *buf = (uint8_t *) &buf16;
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size_t nf = 128, gbe[2];
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size_t nf, gbe[2];
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uint8_t nvmPartChanged[2] = {0, 0}, skipread[2] = {0, 0};
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int e = 1, flags = O_RDWR, rfd, fd, part, gbeFileChanged = 0;
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int e = 1, flags, rfd, fd, part, gbeFileChanged = 0;
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const char *strMac = NULL, *strRMac = "??:??:??:??:??:??", *filename = NULL;
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/* available commands, set a pointer based on user command */
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typedef struct op {
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char *str;
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void (*cmd)(void);
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@ -49,13 +50,16 @@ op_t op[] = {
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};
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void (*cmd)(void) = NULL;
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/* wrappers for BSD-style err() function (error handling) */
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#define ERR() errno = errno ? errno : ECANCELED
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#define err_if(x) if (x) err(ERR(), "%s", filename)
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/* Macro for opening a file with errors properly handled */
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#define xopen(f,l,p) if (opendir(l) != NULL) err(errno = EISDIR, "%s", l); \
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if ((f = open(l, p)) == -1) err(ERR(), "%s", l); \
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if (fstat(f, &st) == -1) err(ERR(), "%s", l)
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/* Macros for reading/writing the GbE file in memory */
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#define word(pos16, partnum) buf16[pos16 + (partnum << 11)]
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#define setWord(pos16, p, val16) if ((gbeFileChanged = 1) && \
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word(pos16, p) != val16) nvmPartChanged[p] = 1 | (word(pos16, p) = val16)
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@ -63,7 +67,7 @@ void (*cmd)(void) = NULL;
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int
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main(int argc, char *argv[])
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{
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if (argc < 3) {
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if (argc < 3) { /* TODO: manpage! */
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fprintf(stderr, "Modify Intel GbE NVM images e.g. set MAC\n");
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fprintf(stderr, "USAGE:\n");
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fprintf(stderr, " %s FILE dump\n", argv[0]);
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@ -74,43 +78,54 @@ main(int argc, char *argv[])
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fprintf(stderr, " %s FILE setchecksum 0|1\n", argv[0]);
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err(errno = ECANCELED, "Too few arguments");
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}
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flags = (strcmp(COMMAND, "dump") == 0) ? O_RDONLY : flags;
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if (strcmp(COMMAND, "dump") == 0)
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flags = O_RDONLY; /* write not needed for dump cmd */
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else
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flags = O_RDWR;
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filename = argv[1];
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#ifdef __OpenBSD__
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/* OpenBSD sandboxing: https://man.openbsd.org/pledge.2 */
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/* Also: https://man.openbsd.org/unveil.2 */
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err_if(unveil("/dev/urandom", "r") == -1);
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if (flags == O_RDONLY) {
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if (flags == O_RDONLY) { /* write not needed for dump command */
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err_if(unveil(filename, "r") == -1);
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err_if(pledge("stdio rpath", NULL) == -1);
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} else {
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} else { /* not dump command, so pledge read-write instead */
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err_if(unveil(filename, "rw") == -1);
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err_if(pledge("stdio rpath wpath", NULL) == -1);
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}
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#endif
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/* open files, but don't read yet; do pledge after, *then* read */
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openFiles(filename);
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#ifdef __OpenBSD__
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/* OpenBSD sandboxing: https://man.openbsd.org/pledge.2 */
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err_if(pledge("stdio", NULL) == -1);
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#endif
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for (int i = 0; i < 6; i++)
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for (int i = 0; i < 6; i++) /* detect user-supplied command */
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if (strcmp(COMMAND, op[i].str) == 0)
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if ((cmd = argc >= op[i].args ? op[i].cmd : NULL))
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break;
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if (cmd == cmd_setmac)
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strMac = (argc > 3) ? MAC_ADDRESS : strRMac;
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else if ((cmd != NULL) && (argc > 3))
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break; /* function ptr set, as per user cmd */
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if (cmd == cmd_setmac) { /* user wishes to set the MAC address */
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strMac = strRMac; /* random mac */
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if (argc > 3) /* user-supplied mac (can be random) */
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strMac = MAC_ADDRESS;
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} else if ((cmd != NULL) && (argc > 3)) { /* user-supplied partnum */
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err_if((errno = (!((part = PARTN[0] - '0') == 0 || part == 1))
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|| PARTN[1] ? EINVAL : errno));
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err_if((errno = (cmd == NULL) ? EINVAL : errno));
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|| PARTN[1] ? EINVAL : errno)); /* only allow '0' or '1' */
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}
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err_if((errno = (cmd == NULL) ? EINVAL : errno)); /* bad user arg */
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readGbe();
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(*cmd)();
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readGbe(); /* read gbe file into memory */
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(*cmd)(); /* operate on gbe file in memory, as per user command */
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if ((gbeFileChanged) && (flags != O_RDONLY) && (cmd != writeGbe))
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writeGbe();
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err_if((errno != 0) && (cmd != cmd_dump));
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return errno;
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writeGbe(); /* not called for swap cmd; swap calls writeGbe */
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err_if((errno != 0) && (cmd != cmd_dump)); /* don't err on dump */
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return errno; /* errno can be set by the dump command */
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}
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/* open gbe file and /dev/urandom, setting permissions */
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void
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openFiles(const char *path)
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{
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@ -119,13 +134,18 @@ openFiles(const char *path)
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if ((st.st_size != (SIZE_4KB << 1)))
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err(errno = ECANCELED, "File `%s` not 8KiB", path);
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xopen(rfd, "/dev/urandom", O_RDONLY);
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errno = errno != ENOTDIR ? errno : 0;
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if (errno == ENOTDIR)
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errno = 0;
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}
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/* read gbe file into memory buffer */
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void
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readGbe(void)
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{
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nf = ((cmd == writeGbe) || (cmd == cmd_copy)) ? SIZE_4KB : nf;
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if ((cmd == writeGbe) || (cmd == cmd_copy))
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nf = SIZE_4KB;
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else
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nf = 128;
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skipread[part ^ 1] = (cmd == cmd_copy) | (cmd == cmd_setchecksum)
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| (cmd == cmd_brick);
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gbe[1] = (gbe[0] = (size_t) buf) + SIZE_4KB;
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@ -133,10 +153,11 @@ readGbe(void)
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if (skipread[p])
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continue;
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err_if(pread(fd, (uint8_t *) gbe[p], nf, p << 12) == -1);
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swap(p);
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swap(p); /* handle big-endian host CPU */
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}
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}
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/* set MAC address and checksum on nvm part */
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void
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cmd_setmac(void)
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{
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@ -151,6 +172,7 @@ cmd_setmac(void)
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}
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}
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/* parse MAC string, write to char buffer */
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int
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macAddress(const char *strMac, uint16_t *mac)
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{
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@ -174,6 +196,7 @@ macAddress(const char *strMac, uint16_t *mac)
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return ((total == 0) | (mac[0] & 1)); /* multicast/all-zero banned */
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}
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/* convert hex char to char value (0-15) */
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uint8_t
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hextonum(char ch)
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{
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@ -183,9 +206,10 @@ hextonum(char ch)
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return ch - 'A' + 10;
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else if ((ch >= 'a') && (ch <= 'f'))
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return ch - 'a' + 10;
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return (ch == '?') ? rhex() : 16;
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return (ch == '?') ? rhex() : 16; /* 16 for error (invalid char) */
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}
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/* random number generator */
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uint8_t
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rhex(void)
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{
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@ -195,6 +219,7 @@ rhex(void)
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return rnum[n--] & 0xf;
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}
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/* print mac address and hexdump of parts */
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void
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cmd_dump(void)
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{
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@ -203,20 +228,26 @@ cmd_dump(void)
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++numInvalid;
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printf("MAC (part %d): ", partnum);
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macf(partnum), hexdump(partnum);
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errno = ((numInvalid < 2) && (partnum)) ? 0 : errno;
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if ((numInvalid < 2) && (partnum))
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errno = 0;
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}
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}
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/* print mac address of part */
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void
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macf(int partnum)
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{
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for (int c = 0; c < 3; c++) {
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uint16_t val16 = word(c, partnum);
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printf("%02x:%02x", val16 & 0xff, val16 >> 8);
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printf(c == 2 ? "\n" : ":");
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if (c == 2)
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printf("\n");
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else
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printf(":");
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}
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}
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/* print hexdump of nvm part */
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void
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hexdump(int partnum)
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{
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@ -227,10 +258,12 @@ hexdump(int partnum)
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if (c == 4)
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printf(" ");
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printf(" %02x %02x", val16 & 0xff, val16 >> 8);
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} printf("\n");
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}
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printf("\n");
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}
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}
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/* correct the checksum on part */
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void
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cmd_setchecksum(void)
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{
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@ -240,6 +273,7 @@ cmd_setchecksum(void)
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setWord(0x3F, part, NVM_CHECKSUM - val16);
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}
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/* intentionally set wrong checksum on part */
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void
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cmd_brick(void)
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{
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@ -247,6 +281,7 @@ cmd_brick(void)
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setWord(0x3F, part, ((word(0x3F, part)) ^ 0xFF));
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}
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/* overwrite the contents of one part with the other */
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void
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cmd_copy(void)
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{
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@ -254,6 +289,7 @@ cmd_copy(void)
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gbe[part ^ 1] = gbe[part]; /* speedhack: copy ptr, not words */
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}
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/* verify nvme part checksum (return 1 if valid) */
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int
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goodChecksum(int partnum)
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{
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@ -266,6 +302,7 @@ goodChecksum(int partnum)
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return (errno = ECANCELED) & 0;
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}
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/* write the nvm parts back to the file */
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void
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writeGbe(void)
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{
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@ -280,6 +317,7 @@ writeGbe(void)
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err_if(close(fd) == -1);
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}
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/* swap byte order on big-endian CPUs. swap skipped on little endian */
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void
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swap(int partnum)
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{
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