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util/nvmutil: remove excessive comments 

Signed-off-by: Leah Rowe <leah@libreboot.org>
master
Leah Rowe 2025-02-25 13:29:16 +00:00
parent e348ea0381
commit d7312260e7
1 changed files with 35 additions and 84 deletions
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119
util/nvmutil/nvmutil.c
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@ -25,9 +25,9 @@ uint8_t hextonum(char chs), rhex(void);
#define COMMAND argv[2] #define COMMAND argv[2]
#define MAC_ADDRESS argv[3] #define MAC_ADDRESS argv[3]
#define PARTN argv[3] #define PARTN argv[3]
#define NVM_CHECKSUM 0xBABA /* checksum value */ #define NVM_CHECKSUM 0xBABA
#define NVM_CHECKSUM_WORD 0x3F /* checksum word position */ #define NVM_CHECKSUM_WORD 0x3F
#define NVM_SIZE 128 /* Area containing NVM words */ #define NVM_SIZE 128
#define SIZE_4KB 0x1000 #define SIZE_4KB 0x1000
#define SIZE_8KB 0x2000 #define SIZE_8KB 0x2000
@ -42,7 +42,6 @@ int flags, rfd, fd, part;
const char *strMac = NULL, *strRMac = "??:??:??:??:??:??", *filename = NULL; const char *strMac = NULL, *strRMac = "??:??:??:??:??:??", *filename = NULL;
/* available commands, set a pointer based on user command */
typedef struct op { typedef struct op {
char *str; char *str;
void (*cmd)(void); void (*cmd)(void);
@ -58,15 +57,12 @@ op_t op[] = {
}; };
void (*cmd)(void) = NULL; void (*cmd)(void) = NULL;
/* wrappers for BSD-style err() function (error handling) */
#define ERR() errno = errno ? errno : ECANCELED #define ERR() errno = errno ? errno : ECANCELED
#define err_if(x) if (x) err(ERR(), "%s", filename) #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 ((f = open(l, p)) == -1) err(ERR(), "%s", l); \ #define xopen(f,l,p) if ((f = open(l, p)) == -1) err(ERR(), "%s", l); \
if (fstat(f, &st) == -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) ((uint16_t *) gbe[partnum])[pos16] #define word(pos16, partnum) ((uint16_t *) gbe[partnum])[pos16]
#define setWord(pos16, p, val16) if (word(pos16, p) != val16) \ #define setWord(pos16, p, val16) if (word(pos16, p) != val16) \
nvmPartChanged[p] = 1 | (word(pos16, p) = val16) nvmPartChanged[p] = 1 | (word(pos16, p) = val16)
@ -75,11 +71,10 @@ int
main(int argc, char *argv[]) main(int argc, char *argv[])
{ {
#ifdef __OpenBSD__ #ifdef __OpenBSD__
/* OpenBSD pledge (sandboxing): https://man.openbsd.org/pledge.2 */
err_if(pledge("stdio rpath wpath unveil", NULL) == -1); err_if(pledge("stdio rpath wpath unveil", NULL) == -1);
#endif #endif
if (argc < 2) { /* TODO: manpage! */ if (argc < 2) {
#ifdef __OpenBSD__ #ifdef __OpenBSD__
err_if(pledge("stdio", NULL) == -1); err_if(pledge("stdio", NULL) == -1);
#endif #endif
@ -102,38 +97,32 @@ main(int argc, char *argv[])
if (argc > 2) { if (argc > 2) {
if (strcmp(COMMAND, "dump") == 0) { if (strcmp(COMMAND, "dump") == 0) {
flags = O_RDONLY; /* write not needed for dump cmd */ flags = O_RDONLY;
#ifdef __OpenBSD__ #ifdef __OpenBSD__
/* writes not needed for the dump command */
err_if(pledge("stdio rpath unveil", NULL) == -1); err_if(pledge("stdio rpath unveil", NULL) == -1);
#endif #endif
} }
} }
/* check for dir first, to prevent unveil from
permitting directory access on OpenBSD */
checkdir("/dev/urandom"); checkdir("/dev/urandom");
checkdir(filename); /* Must be a file, not a directory */ checkdir(filename);
#ifdef __OpenBSD__ #ifdef __OpenBSD__
/* OpenBSD unveil: https://man.openbsd.org/unveil.2 */
err_if(unveil("/dev/urandom", "r") == -1); err_if(unveil("/dev/urandom", "r") == -1);
/* Only allow access to /dev/urandom and the gbe file */ if (flags == O_RDONLY) {
if (flags == O_RDONLY) { /* dump command */ err_if(unveil(filename, "r") == -1);
err_if(unveil(filename, "r") == -1); /* write not needed */ err_if(unveil(NULL, NULL) == -1);
err_if(unveil(NULL, NULL) == -1); /* lock unveil */ err_if(pledge("stdio rpath", NULL) == -1);
err_if(pledge("stdio rpath", NULL) == -1); /* lock unveil */ } else {
} else { /* other commands need read-write */
err_if(unveil(filename, "rw") == -1); err_if(unveil(filename, "rw") == -1);
err_if(unveil(NULL, NULL) == -1); /* lock unveil */ err_if(unveil(NULL, NULL) == -1);
err_if(pledge("stdio rpath wpath", NULL) == -1); /* no unveil */ err_if(pledge("stdio rpath wpath", NULL) == -1);
} }
#endif #endif
openFiles(filename); /* open files first, to allow harder pledge: */ openFiles(filename);
#ifdef __OpenBSD__ #ifdef __OpenBSD__
/* OpenBSD sandboxing: https://man.openbsd.org/pledge.2 */
err_if(pledge("stdio", NULL) == -1); err_if(pledge("stdio", NULL) == -1);
#endif #endif
@ -157,29 +146,22 @@ main(int argc, char *argv[])
cmd = cmd_setmac; cmd = cmd_setmac;
} else if (cmd == cmd_setmac) { /* nvm gbe setmac [MAC] */ } else if (cmd == cmd_setmac) { /* nvm gbe setmac [MAC] */
strMac = strRMac; /* random MAC */ strMac = strRMac; /* random MAC */
if (argc > 3) /* user-supplied MAC (can be random) */ if (argc > 3)
strMac = MAC_ADDRESS; strMac = MAC_ADDRESS;
} else if ((cmd != NULL) && (argc > 3)) { /* user-supplied partnum */ } else if ((cmd != NULL) && (argc > 3)) { /* user-supplied partnum */
err_if((errno = (!((part = PARTN[0] - '0') == 0 || part == 1)) err_if((errno = (!((part = PARTN[0] - '0') == 0 || part == 1))
|| PARTN[1] ? EINVAL : errno)); /* only allow '0' or '1' */ || PARTN[1] ? EINVAL : errno)); /* only allow '0' or '1' */
} }
err_if((errno = (cmd == NULL) ? EINVAL : errno)); /* bad user arg */ err_if((errno = (cmd == NULL) ? EINVAL : errno));
readGbe(); /* read gbe file into memory */ readGbe();
(*cmd)();
writeGbe();
(*cmd)(); /* operate on gbe file in memory */ err_if((errno != 0) && (cmd != cmd_dump));
return errno;
writeGbe(); /* write changes back to file */
err_if((errno != 0) && (cmd != cmd_dump)); /* don't err on dump */
return errno; /* errno can be set by the dump command */
} }
/*
* check whether urandom/file is a directory, and err if so,
* to prevent later unveil calls from permitting directory access
* on OpenBSD
*/
void void
checkdir(const char *path) checkdir(const char *path)
{ {
@ -190,13 +172,12 @@ checkdir(const char *path)
err_if(errno); err_if(errno);
} }
/* open gbe file and /dev/urandom, setting permissions */
void void
openFiles(const char *path) openFiles(const char *path)
{ {
struct stat st; struct stat st;
xopen(fd, path, flags); /* gbe file */ xopen(fd, path, flags);
switch(st.st_size) { switch(st.st_size) {
case SIZE_8KB: case SIZE_8KB:
@ -209,40 +190,32 @@ openFiles(const char *path)
break; break;
} }
/* the MAC address randomiser relies on reading urandom */
xopen(rfd, "/dev/urandom", O_RDONLY); xopen(rfd, "/dev/urandom", O_RDONLY);
} }
/* read gbe file into memory buffer */
void void
readGbe(void) readGbe(void)
{ {
if ((cmd == cmd_swap) || (cmd == cmd_copy)) if ((cmd == cmd_swap) || (cmd == cmd_copy))
nf = SIZE_4KB; /* read/write the entire block */ nf = SIZE_4KB;
/* only need to do 4KB even on larger gbe files */
else else
nf = NVM_SIZE; /* only read/write the nvm part of the block */ nf = NVM_SIZE;
if ((cmd == cmd_copy) || (cmd == cmd_setchecksum) || (cmd == cmd_brick)) if ((cmd == cmd_copy) || (cmd == cmd_setchecksum) || (cmd == cmd_brick))
do_read[part ^ 1] = 0; /* only read the user-specified part */ do_read[part ^ 1] = 0;
/* AND do_read[*] to avoid wasteful malloc */
/* cmd_copy also relies on this */
char *buf = malloc(nf << (do_read[0] & do_read[1])); char *buf = malloc(nf << (do_read[0] & do_read[1]));
if (buf == NULL) if (buf == NULL)
err(errno, NULL); err(errno, NULL);
/* we pread per-part, so each part has its own pointer: */
/* if a do_read is 0, both pointers are the same; this accomplishes
the desired result for cmd_copy (see cmd_copy function) */
gbe[0] = (size_t) buf; gbe[0] = (size_t) buf;
gbe[1] = gbe[0] + (nf * (do_read[0] & do_read[1])); gbe[1] = gbe[0] + (nf * (do_read[0] & do_read[1]));
ssize_t tnr = 0; /* total bytes read */ ssize_t tnr = 0;
for (int p = 0; p < 2; p++) { for (int p = 0; p < 2; p++) {
if (!do_read[p]) if (!do_read[p])
continue; /* avoid unnecessary reads */ continue;
ssize_t nr = pread(fd, (uint8_t *) gbe[p], nf, p * partsize); ssize_t nr = pread(fd, (uint8_t *) gbe[p], nf, p * partsize);
err_if(nr == -1); err_if(nr == -1);
@ -252,14 +225,12 @@ readGbe(void)
nr, filename, nf); nr, filename, nf);
tnr += nr; tnr += nr;
swap(p); /* handle big-endian host CPU */ swap(p); /* handle big-endian host CPU */
} }
printf("%ld bytes read from file '%s'\n", tnr, filename); printf("%ld bytes read from file '%s'\n", tnr, filename);
} }
/* set MAC address and checksum on nvm part */
void void
cmd_setmac(void) cmd_setmac(void)
{ {
@ -272,21 +243,20 @@ cmd_setmac(void)
if (!goodChecksum(part = partnum)) if (!goodChecksum(part = partnum))
continue; continue;
for (int w = 0; w < 3; w++) /* write MAC to gbe part */ for (int w = 0; w < 3; w++)
setWord(w, partnum, mac[w]); setWord(w, partnum, mac[w]);
printf("Wrote MAC address to part %d: ", partnum); printf("Wrote MAC address to part %d: ", partnum);
macf(partnum); macf(partnum);
cmd_setchecksum(); /* MAC updated; need valid checksum */ cmd_setchecksum();
mac_updated = 1; mac_updated = 1;
} }
if (mac_updated) if (mac_updated)
errno = 0; /* reset in case one of the checksums failed */ errno = 0;
} }
/* parse MAC string, write to char buffer */
void void
parseMacString(const char *strMac, uint16_t *mac) parseMacString(const char *strMac, uint16_t *mac)
{ {
@ -303,14 +273,12 @@ parseMacString(const char *strMac, uint16_t *mac)
int byte = i / 3; int byte = i / 3;
/* Update MAC buffer per-nibble from a given string */
for (int nib = 0; nib < 2; nib++, total += h) { for (int nib = 0; nib < 2; nib++, total += h) {
if ((h = hextonum(strMac[i + nib])) > 15) if ((h = hextonum(strMac[i + nib])) > 15)
err(errno = EINVAL, "Invalid character '%c'", err(errno = EINVAL, "Invalid character '%c'",
strMac[i + nib]); strMac[i + nib]);
/* if random: ensure local-only, unicast MAC */ if ((byte == 0) && (nib == 1))
if ((byte == 0) && (nib == 1)) /* unicast/local nib */
if (strMac[i + nib] == '?') /* ?=random */ if (strMac[i + nib] == '?') /* ?=random */
h = (h & 0xE) | 2; /* local, unicast */ h = (h & 0xE) | 2; /* local, unicast */
@ -325,7 +293,6 @@ parseMacString(const char *strMac, uint16_t *mac)
err(errno = EINVAL, "Invalid MAC (multicast bit set)"); err(errno = EINVAL, "Invalid MAC (multicast bit set)");
} }
/* convert hex char to char value (0-15) */
uint8_t uint8_t
hextonum(char ch) hextonum(char ch)
{ {
@ -335,10 +302,9 @@ hextonum(char ch)
return ch - 'A' + 10; return ch - 'A' + 10;
else if ((ch >= 'a') && (ch <= 'f')) else if ((ch >= 'a') && (ch <= 'f'))
return ch - 'a' + 10; return ch - 'a' + 10;
return (ch == '?') ? rhex() : 16; /* 16 for error (invalid char) */ return (ch == '?') ? rhex() : 16;
} }
/* random number generator */
uint8_t uint8_t
rhex(void) rhex(void)
{ {
@ -348,7 +314,6 @@ rhex(void)
return rnum[n--] & 0xf; return rnum[n--] & 0xf;
} }
/* print mac address and hexdump of parts */
void void
cmd_dump(void) cmd_dump(void)
{ {
@ -369,7 +334,6 @@ cmd_dump(void)
} }
} }
/* print mac address of part */
void void
macf(int partnum) macf(int partnum)
{ {
@ -383,7 +347,6 @@ macf(int partnum)
} }
} }
/* print hexdump of nvm part */
void void
hexdump(int partnum) hexdump(int partnum)
{ {
@ -399,7 +362,6 @@ hexdump(int partnum)
} }
} }
/* correct the checksum on part */
void void
cmd_setchecksum(void) cmd_setchecksum(void)
{ {
@ -407,11 +369,9 @@ cmd_setchecksum(void)
for (int c = 0; c < NVM_CHECKSUM_WORD; c++) for (int c = 0; c < NVM_CHECKSUM_WORD; c++)
val16 += word(c, part); val16 += word(c, part);
/* correct the checksum */
setWord(NVM_CHECKSUM_WORD, part, NVM_CHECKSUM - val16); setWord(NVM_CHECKSUM_WORD, part, NVM_CHECKSUM - val16);
} }
/* intentionally set wrong checksum on part */
void void
cmd_brick(void) cmd_brick(void)
{ {
@ -420,23 +380,17 @@ cmd_brick(void)
((word(NVM_CHECKSUM_WORD, part)) ^ 0xFF)); ((word(NVM_CHECKSUM_WORD, part)) ^ 0xFF));
} }
/* overwrite the contents of one part with the other */
void void
cmd_copy(void) cmd_copy(void)
{ {
nvmPartChanged[part ^ 1] = goodChecksum(part); nvmPartChanged[part ^ 1] = goodChecksum(part);
/* no need to actually copy because gbe[] pointers are both the same */
/* we simply set the right nvm part as changed, and write the file */
} }
/* swap contents between the two parts */
void void
cmd_swap(void) { cmd_swap(void) {
err_if(!(goodChecksum(0) || goodChecksum(1))); err_if(!(goodChecksum(0) || goodChecksum(1)));
errno = 0; errno = 0;
/* speedhack: swap pointers, not words. (xor swap) */
gbe[0] ^= gbe[1]; gbe[0] ^= gbe[1];
gbe[1] ^= gbe[0]; gbe[1] ^= gbe[0];
gbe[0] ^= gbe[1]; gbe[0] ^= gbe[1];
@ -444,7 +398,6 @@ cmd_swap(void) {
nvmPartChanged[0] = nvmPartChanged[1] = 1; nvmPartChanged[0] = nvmPartChanged[1] = 1;
} }
/* verify nvm part checksum (return 1 if valid) */
int int
goodChecksum(int partnum) goodChecksum(int partnum)
{ {
@ -460,11 +413,10 @@ goodChecksum(int partnum)
return 0; return 0;
} }
/* write the nvm parts back to the file */
void void
writeGbe(void) writeGbe(void)
{ {
ssize_t tnw = 0; /* total bytes written */ ssize_t tnw = 0;
for (int p = 0; p < 2; p++) { for (int p = 0; p < 2; p++) {
if ((!nvmPartChanged[p]) || (flags == O_RDONLY)) if ((!nvmPartChanged[p]) || (flags == O_RDONLY))
@ -498,10 +450,9 @@ writeGbe(void)
err_if(close(fd) == -1); err_if(close(fd) == -1);
} }
/* swap byte order on big-endian CPUs. swap skipped on little endian */
void void
swap(int partnum) /* swaps bytes in words, not pointers. */ swap(int partnum)
{ /* not to be confused with cmd_swap */ {
size_t w, x; size_t w, x;
uint8_t *n = (uint8_t *) gbe[partnum]; uint8_t *n = (uint8_t *) gbe[partnum];
int e = 1; int e = 1;