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Diffstat (limited to 'util/nvmutil/nvmutil.c')
-rw-r--r--util/nvmutil/nvmutil.c92
1 files changed, 65 insertions, 27 deletions
diff --git a/util/nvmutil/nvmutil.c b/util/nvmutil/nvmutil.c
index 68bb95da..520b2078 100644
--- a/util/nvmutil/nvmutil.c
+++ b/util/nvmutil/nvmutil.c
@@ -28,12 +28,13 @@ uint8_t hextonum(char chs), rhex(void);
uint16_t buf16[SIZE_4KB], mac[3] = {0, 0, 0};
uint8_t *buf = (uint8_t *) &buf16;
-size_t nf = 128, gbe[2];
+size_t nf, gbe[2];
uint8_t nvmPartChanged[2] = {0, 0}, skipread[2] = {0, 0};
-int e = 1, flags = O_RDWR, rfd, fd, part, gbeFileChanged = 0;
+int e = 1, flags, rfd, fd, part, gbeFileChanged = 0;
const char *strMac = NULL, *strRMac = "??:??:??:??:??:??", *filename = NULL;
+/* available commands, set a pointer based on user command */
typedef struct op {
char *str;
void (*cmd)(void);
@@ -49,13 +50,16 @@ op_t op[] = {
};
void (*cmd)(void) = NULL;
+/* wrappers for BSD-style err() function (error handling) */
#define ERR() errno = errno ? errno : ECANCELED
#define err_if(x) if (x) err(ERR(), "%s", filename)
+/* Macro for opening a file with errors properly handled */
#define xopen(f,l,p) if (opendir(l) != NULL) err(errno = EISDIR, "%s", l); \
if ((f = open(l, p)) == -1) err(ERR(), "%s", l); \
if (fstat(f, &st) == -1) err(ERR(), "%s", l)
+/* Macros for reading/writing the GbE file in memory */
#define word(pos16, partnum) buf16[pos16 + (partnum << 11)]
#define setWord(pos16, p, val16) if ((gbeFileChanged = 1) && \
word(pos16, p) != val16) nvmPartChanged[p] = 1 | (word(pos16, p) = val16)
@@ -63,7 +67,7 @@ void (*cmd)(void) = NULL;
int
main(int argc, char *argv[])
{
- if (argc < 3) {
+ if (argc < 3) { /* TODO: manpage! */
fprintf(stderr, "Modify Intel GbE NVM images e.g. set MAC\n");
fprintf(stderr, "USAGE:\n");
fprintf(stderr, " %s FILE dump\n", argv[0]);
@@ -74,43 +78,54 @@ main(int argc, char *argv[])
fprintf(stderr, " %s FILE setchecksum 0|1\n", argv[0]);
err(errno = ECANCELED, "Too few arguments");
}
- flags = (strcmp(COMMAND, "dump") == 0) ? O_RDONLY : flags;
+ if (strcmp(COMMAND, "dump") == 0)
+ flags = O_RDONLY; /* write not needed for dump cmd */
+ else
+ flags = O_RDWR;
filename = argv[1];
#ifdef __OpenBSD__
+ /* OpenBSD sandboxing: https://man.openbsd.org/pledge.2 */
+ /* Also: https://man.openbsd.org/unveil.2 */
err_if(unveil("/dev/urandom", "r") == -1);
- if (flags == O_RDONLY) {
+ if (flags == O_RDONLY) { /* write not needed for dump command */
err_if(unveil(filename, "r") == -1);
err_if(pledge("stdio rpath", NULL) == -1);
- } else {
+ } else { /* not dump command, so pledge read-write instead */
err_if(unveil(filename, "rw") == -1);
err_if(pledge("stdio rpath wpath", NULL) == -1);
}
#endif
+ /* open files, but don't read yet; do pledge after, *then* read */
openFiles(filename);
#ifdef __OpenBSD__
+ /* OpenBSD sandboxing: https://man.openbsd.org/pledge.2 */
err_if(pledge("stdio", NULL) == -1);
#endif
- for (int i = 0; i < 6; i++)
+ for (int i = 0; i < 6; i++) /* detect user-supplied command */
if (strcmp(COMMAND, op[i].str) == 0)
if ((cmd = argc >= op[i].args ? op[i].cmd : NULL))
- break;
- if (cmd == cmd_setmac)
- strMac = (argc > 3) ? MAC_ADDRESS : strRMac;
- else if ((cmd != NULL) && (argc > 3))
+ break; /* function ptr set, as per user cmd */
+ if (cmd == cmd_setmac) { /* user wishes to set the MAC address */
+ strMac = strRMac; /* random mac */
+ if (argc > 3) /* user-supplied mac (can be random) */
+ strMac = MAC_ADDRESS;
+ } else if ((cmd != NULL) && (argc > 3)) { /* user-supplied partnum */
err_if((errno = (!((part = PARTN[0] - '0') == 0 || part == 1))
- || PARTN[1] ? EINVAL : errno));
- err_if((errno = (cmd == NULL) ? EINVAL : errno));
+ || PARTN[1] ? EINVAL : errno)); /* only allow '0' or '1' */
+ }
+ err_if((errno = (cmd == NULL) ? EINVAL : errno)); /* bad user arg */
- readGbe();
- (*cmd)();
+ readGbe(); /* read gbe file into memory */
+ (*cmd)(); /* operate on gbe file in memory, as per user command */
if ((gbeFileChanged) && (flags != O_RDONLY) && (cmd != writeGbe))
- writeGbe();
- err_if((errno != 0) && (cmd != cmd_dump));
- return errno;
+ writeGbe(); /* not called for swap cmd; swap calls writeGbe */
+ err_if((errno != 0) && (cmd != cmd_dump)); /* don't err on dump */
+ return errno; /* errno can be set by the dump command */
}
+/* open gbe file and /dev/urandom, setting permissions */
void
openFiles(const char *path)
{
@@ -119,13 +134,18 @@ openFiles(const char *path)
if ((st.st_size != (SIZE_4KB << 1)))
err(errno = ECANCELED, "File `%s` not 8KiB", path);
xopen(rfd, "/dev/urandom", O_RDONLY);
- errno = errno != ENOTDIR ? errno : 0;
+ if (errno == ENOTDIR)
+ errno = 0;
}
+/* read gbe file into memory buffer */
void
readGbe(void)
{
- nf = ((cmd == writeGbe) || (cmd == cmd_copy)) ? SIZE_4KB : nf;
+ if ((cmd == writeGbe) || (cmd == cmd_copy))
+ nf = SIZE_4KB;
+ else
+ nf = 128;
skipread[part ^ 1] = (cmd == cmd_copy) | (cmd == cmd_setchecksum)
| (cmd == cmd_brick);
gbe[1] = (gbe[0] = (size_t) buf) + SIZE_4KB;
@@ -133,10 +153,11 @@ readGbe(void)
if (skipread[p])
continue;
err_if(pread(fd, (uint8_t *) gbe[p], nf, p << 12) == -1);
- swap(p);
+ swap(p); /* handle big-endian host CPU */
}
}
+/* set MAC address and checksum on nvm part */
void
cmd_setmac(void)
{
@@ -151,6 +172,7 @@ cmd_setmac(void)
}
}
+/* parse MAC string, write to char buffer */
int
macAddress(const char *strMac, uint16_t *mac)
{
@@ -174,6 +196,7 @@ macAddress(const char *strMac, uint16_t *mac)
return ((total == 0) | (mac[0] & 1)); /* multicast/all-zero banned */
}
+/* convert hex char to char value (0-15) */
uint8_t
hextonum(char ch)
{
@@ -183,9 +206,10 @@ hextonum(char ch)
return ch - 'A' + 10;
else if ((ch >= 'a') && (ch <= 'f'))
return ch - 'a' + 10;
- return (ch == '?') ? rhex() : 16;
+ return (ch == '?') ? rhex() : 16; /* 16 for error (invalid char) */
}
+/* random number generator */
uint8_t
rhex(void)
{
@@ -195,6 +219,7 @@ rhex(void)
return rnum[n--] & 0xf;
}
+/* print mac address and hexdump of parts */
void
cmd_dump(void)
{
@@ -203,20 +228,26 @@ cmd_dump(void)
++numInvalid;
printf("MAC (part %d): ", partnum);
macf(partnum), hexdump(partnum);
- errno = ((numInvalid < 2) && (partnum)) ? 0 : errno;
+ if ((numInvalid < 2) && (partnum))
+ errno = 0;
}
}
+/* print mac address of part */
void
macf(int partnum)
{
for (int c = 0; c < 3; c++) {
uint16_t val16 = word(c, partnum);
printf("%02x:%02x", val16 & 0xff, val16 >> 8);
- printf(c == 2 ? "\n" : ":");
+ if (c == 2)
+ printf("\n");
+ else
+ printf(":");
}
}
+/* print hexdump of nvm part */
void
hexdump(int partnum)
{
@@ -227,10 +258,12 @@ hexdump(int partnum)
if (c == 4)
printf(" ");
printf(" %02x %02x", val16 & 0xff, val16 >> 8);
- } printf("\n");
+ }
+ printf("\n");
}
}
+/* correct the checksum on part */
void
cmd_setchecksum(void)
{
@@ -240,6 +273,7 @@ cmd_setchecksum(void)
setWord(0x3F, part, NVM_CHECKSUM - val16);
}
+/* intentionally set wrong checksum on part */
void
cmd_brick(void)
{
@@ -247,6 +281,7 @@ cmd_brick(void)
setWord(0x3F, part, ((word(0x3F, part)) ^ 0xFF));
}
+/* overwrite the contents of one part with the other */
void
cmd_copy(void)
{
@@ -254,6 +289,7 @@ cmd_copy(void)
gbe[part ^ 1] = gbe[part]; /* speedhack: copy ptr, not words */
}
+/* verify nvme part checksum (return 1 if valid) */
int
goodChecksum(int partnum)
{
@@ -266,6 +302,7 @@ goodChecksum(int partnum)
return (errno = ECANCELED) & 0;
}
+/* write the nvm parts back to the file */
void
writeGbe(void)
{
@@ -273,13 +310,14 @@ writeGbe(void)
for (int p = 0, x = (cmd == writeGbe) ? 1 : 0; p < 2; p++) {
if ((!nvmPartChanged[p]) && (cmd != writeGbe))
continue;
- swap(p^x);
- err_if(pwrite(fd, (uint8_t *) gbe[p^x], nf, p << 12) == -1);
+ swap(p ^ x);
+ err_if(pwrite(fd, (uint8_t *) gbe[p ^ x], nf, p << 12) == -1);
}
errno = 0;
err_if(close(fd) == -1);
}
+/* swap byte order on big-endian CPUs. swap skipped on little endian */
void
swap(int partnum)
{
generated by cgit v1.2.1 (git 2.18.0) at 2025-10-31 02:16:29 +0000