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logd: log_strtok_r deal with nuls
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Rename to log_strntok_r and change from dealing with strings
to dealing with a string and an associated length.

Bug: 23517551
Change-Id: Ia72f1305a53f55eeef9861ac378fb8205fd2378e
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Mark Salyzyn authored and Steve Kondik committed Nov 1, 2015
1 parent 064c3a5 commit c5a324f
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Showing 3 changed files with 67 additions and 32 deletions.
82 changes: 58 additions & 24 deletions logd/LogKlog.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -39,14 +39,15 @@ static const char priority_message[] = { KMSG_PRIORITY(LOG_INFO), '\0' };
// Parsing is hard

// called if we see a '<', s is the next character, returns pointer after '>'
static char *is_prio(char *s) {
if (!isdigit(*s++)) {
static char *is_prio(char *s, size_t len) {
if (!len || !isdigit(*s++)) {
return NULL;
}
static const size_t max_prio_len = 4;
size_t len = 0;
--len;
static const size_t max_prio_len = (len < 4) ? len : 4;
size_t priolen = 0;
char c;
while (((c = *s++)) && (++len <= max_prio_len)) {
while (((c = *s++)) && (++priolen <= max_prio_len)) {
if (!isdigit(c)) {
return ((c == '>') && (*s == '[')) ? s : NULL;
}
Expand All @@ -55,16 +56,19 @@ static char *is_prio(char *s) {
}

// called if we see a '[', s is the next character, returns pointer after ']'
static char *is_timestamp(char *s) {
while (*s == ' ') {
static char *is_timestamp(char *s, size_t len) {
while (len && (*s == ' ')) {
++s;
--len;
}
if (!isdigit(*s++)) {
if (!len || !isdigit(*s++)) {
return NULL;
}
--len;
bool first_period = true;
char c;
while ((c = *s++)) {
while (len && ((c = *s++))) {
--len;
if ((c == '.') && first_period) {
first_period = false;
} else if (!isdigit(c)) {
Expand All @@ -87,7 +91,11 @@ static char *is_timestamp(char *s) {
// space is one more than <digit> of 9
#define OPEN_BRACKET_SPACE ((char)(OPEN_BRACKET_SIG | 10))

char *log_strtok_r(char *s, char **last) {
char *log_strntok_r(char *s, size_t *len, char **last, size_t *sublen) {
*sublen = 0;
if (!*len) {
return NULL;
}
if (!s) {
if (!(s = *last)) {
return NULL;
Expand All @@ -97,6 +105,7 @@ char *log_strtok_r(char *s, char **last) {
if ((*s & SIGNATURE_MASK) == LESS_THAN_SIG) {
*s = (*s & ~SIGNATURE_MASK) + '0';
*--s = '<';
++*len;
}
// fixup for log signature split [,
// OPEN_BRACKET_SPACE is space, OPEN_BRACKET_SIG + <digit>
Expand All @@ -107,32 +116,38 @@ char *log_strtok_r(char *s, char **last) {
*s = (*s & ~SIGNATURE_MASK) + '0';
}
*--s = '[';
++*len;
}
}

s += strspn(s, "\r\n");
while (*len && ((*s == '\r') || (*s == '\n'))) {
++s;
--*len;
}

if (!*s) { // no non-delimiter characters
if (!*len) {
*last = NULL;
return NULL;
}
char *peek, *tok = s;

for (;;) {
char c = *s++;
switch (c) {
case '\0':
if (*len == 0) {
*last = NULL;
return tok;

}
char c = *s++;
--*len;
size_t adjust;
switch (c) {
case '\r':
case '\n':
s[-1] = '\0';
*last = s;
return tok;

case '<':
peek = is_prio(s);
peek = is_prio(s, *len);
if (!peek) {
break;
}
Expand All @@ -143,14 +158,26 @@ char *log_strtok_r(char *s, char **last) {
*last = s;
return tok;
}
adjust = peek - s;
if (adjust > *len) {
adjust = *len;
}
*sublen += adjust;
*len -= adjust;
s = peek;
if ((*s == '[') && ((peek = is_timestamp(s + 1)))) {
if ((*s == '[') && ((peek = is_timestamp(s + 1, *len - 1)))) {
adjust = peek - s;
if (adjust > *len) {
adjust = *len;
}
*sublen += adjust;
*len -= adjust;
s = peek;
}
break;

case '[':
peek = is_timestamp(s);
peek = is_timestamp(s, *len);
if (!peek) {
break;
}
Expand All @@ -165,9 +192,16 @@ char *log_strtok_r(char *s, char **last) {
*last = s;
return tok;
}
adjust = peek - s;
if (adjust > *len) {
adjust = *len;
}
*sublen += adjust;
*len -= adjust;
s = peek;
break;
}
++*sublen;
}
// NOTREACHED
}
Expand Down Expand Up @@ -214,13 +248,13 @@ bool LogKlog::onDataAvailable(SocketClient *cli) {
bool full = len == (sizeof(buffer) - 1);
char *ep = buffer + len;
*ep = '\0';
len = 0;
size_t sublen;
for(char *ptr = NULL, *tok = buffer;
((tok = log_strtok_r(tok, &ptr)));
((tok = log_strntok_r(tok, &len, &ptr, &sublen)));
tok = NULL) {
if (((tok + strlen(tok)) == ep) && (retval != 0) && full) {
len = strlen(tok);
memmove(buffer, tok, len);
if (((tok + sublen) >= ep) && (retval != 0) && full) {
memmove(buffer, tok, sublen);
len = sublen;
break;
}
if (*tok) {
Expand Down
2 changes: 1 addition & 1 deletion logd/LogKlog.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@
#include <log/log_read.h>
#include "LogReader.h"

char *log_strtok_r(char *str, char **saveptr);
char *log_strntok_r(char *s, size_t *len, char **saveptr, size_t *sublen);

class LogKlog : public SocketListener {
LogBuffer *logbuf;
Expand Down
15 changes: 8 additions & 7 deletions logd/main.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -287,30 +287,31 @@ static void readDmesg(LogAudit *al, LogKlog *kl) {
return;
}

int len = klogctl(KLOG_SIZE_BUFFER, NULL, 0);
if (len <= 0) {
int rc = klogctl(KLOG_SIZE_BUFFER, NULL, 0);
if (rc <= 0) {
return;
}

len += 1024; // Margin for additional input race or trailing nul
size_t len = rc + 1024; // Margin for additional input race or trailing nul
std::unique_ptr<char []> buf(new char[len]);

int rc = klogctl(KLOG_READ_ALL, buf.get(), len);
rc = klogctl(KLOG_READ_ALL, buf.get(), len);
if (rc <= 0) {
return;
}

if (rc < len) {
if ((size_t)rc < len) {
len = rc + 1;
}
buf[len - 1] = '\0';
buf[--len] = '\0';

if (kl) {
kl->synchronize(buf.get(), len);
}

size_t sublen;
for (char *ptr = NULL, *tok = buf.get();
(rc >= 0) && ((tok = log_strtok_r(tok, &ptr)));
(rc >= 0) && ((tok = log_strntok_r(tok, &len, &ptr, &sublen)));
tok = NULL) {
if (al) {
rc = al->log(tok, sublen);
Expand Down

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