Add '-t N' flag to logcat, to print only the last N lines of logcat
(to be used in capturing a merged mini logcat for crash reports)
Change-Id: I68149eb80f2f79812f43b07d80fbea822476859e
diff --git a/logcat/logcat.cpp b/logcat/logcat.cpp
index 670408c..4b23c8d 100644
--- a/logcat/logcat.cpp
+++ b/logcat/logcat.cpp
@@ -25,6 +25,7 @@
static AndroidLogFormat * g_logformat;
static bool g_nonblock = false;
+static int g_tail_lines = 0;
/* logd prefixes records with a length field */
#define RECORD_LENGTH_FIELD_SIZE_BYTES sizeof(uint32_t)
@@ -162,19 +163,6 @@
AndroidLogEntry entry;
char binaryMsgBuf[1024];
- if (!dev->printed) {
- dev->printed = true;
- if (g_devCount > 1) {
- snprintf(binaryMsgBuf, sizeof(binaryMsgBuf), "--------- beginning of %s\n",
- dev->device);
- bytesWritten = write(g_outFD, binaryMsgBuf, strlen(binaryMsgBuf));
- if (bytesWritten < 0) {
- perror("output error");
- exit(-1);
- }
- }
- }
-
if (dev->binary) {
err = android_log_processBinaryLogBuffer(buf, &entry, g_eventTagMap,
binaryMsgBuf, sizeof(binaryMsgBuf));
@@ -219,47 +207,51 @@
return;
}
-static void chooseFirst(log_device_t* dev, log_device_t** firstdev, queued_entry_t** firstentry) {
- *firstdev = NULL;
- *firstentry = NULL;
- int i=0;
- for (; dev; dev=dev->next) {
- i++;
- if (dev->queue) {
- if ((*firstentry) == NULL || cmp(dev->queue, *firstentry) < 0) {
- (*firstentry) = dev->queue;
- *firstdev = dev;
+static void chooseFirst(log_device_t* dev, log_device_t** firstdev) {
+ for (*firstdev = NULL; dev != NULL; dev = dev->next) {
+ if (dev->queue != NULL && (*firstdev == NULL || cmp(dev->queue, (*firstdev)->queue) < 0)) {
+ *firstdev = dev;
+ }
+ }
+}
+
+static void maybePrintStart(log_device_t* dev) {
+ if (!dev->printed) {
+ dev->printed = true;
+ if (g_devCount > 1 && !g_printBinary) {
+ char buf[1024];
+ snprintf(buf, sizeof(buf), "--------- beginning of %s\n", dev->device);
+ if (write(g_outFD, buf, strlen(buf)) < 0) {
+ perror("output error");
+ exit(-1);
}
}
}
}
-static void printEntry(log_device_t* dev, queued_entry_t* entry) {
- if (g_printBinary) {
- printBinary(&entry->entry);
- } else {
- processBuffer(dev, &entry->entry);
- }
-}
-
-static void eatEntry(log_device_t* dev, queued_entry_t* entry) {
- if (dev->queue != entry) {
- perror("assertion failed: entry isn't first in queue");
- exit(1);
- }
- printEntry(dev, entry);
+static void skipNextEntry(log_device_t* dev) {
+ maybePrintStart(dev);
+ queued_entry_t* entry = dev->queue;
dev->queue = entry->next;
delete entry;
}
+static void printNextEntry(log_device_t* dev) {
+ maybePrintStart(dev);
+ if (g_printBinary) {
+ printBinary(&dev->queue->entry);
+ } else {
+ processBuffer(dev, &dev->queue->entry);
+ }
+ skipNextEntry(dev);
+}
+
static void readLogLines(log_device_t* devices)
{
log_device_t* dev;
int max = 0;
- queued_entry_t* entry;
- queued_entry_t* old;
int ret;
- bool somethingForEveryone;
+ int queued_lines = 0;
bool sleep = true;
int result;
@@ -284,7 +276,7 @@
if (result >= 0) {
for (dev=devices; dev; dev = dev->next) {
if (FD_ISSET(dev->fd, &readset)) {
- entry = new queued_entry_t;
+ queued_entry_t* entry = new queued_entry_t;
/* NOTE: driver guarantees we read exactly one full entry */
ret = read(dev->fd, entry->buf, LOGGER_ENTRY_MAX_LEN);
if (ret < 0) {
@@ -307,36 +299,45 @@
entry->entry.msg[entry->entry.len] = '\0';
dev->enqueue(entry);
+ ++queued_lines;
}
}
if (result == 0) {
// we did our short timeout trick and there's nothing new
- // print all that aren't the last in their list
+ // print everything we have and wait for more data
sleep = true;
while (true) {
- chooseFirst(devices, &dev, &entry);
- if (!entry) {
+ chooseFirst(devices, &dev);
+ if (dev == NULL) {
break;
}
- eatEntry(dev, entry);
+ if (g_tail_lines == 0 || queued_lines <= g_tail_lines) {
+ printNextEntry(dev);
+ } else {
+ skipNextEntry(dev);
+ }
+ --queued_lines;
}
- // They requested to just dump the log
+
+ // the caller requested to just dump the log and exit
if (g_nonblock) {
exit(0);
}
} else {
// print all that aren't the last in their list
- while (true) {
- chooseFirst(devices, &dev, &entry);
- if (!entry) {
- sleep = false;
- break;
- } else if (entry->next == NULL) {
- sleep = false;
+ sleep = false;
+ while (g_tail_lines == 0 || queued_lines > g_tail_lines) {
+ chooseFirst(devices, &dev);
+ if (dev == NULL || dev->queue->next == NULL) {
break;
}
- eatEntry(dev, entry);
+ if (g_tail_lines == 0) {
+ printNextEntry(dev);
+ } else {
+ skipNextEntry(dev);
+ }
+ --queued_lines;
}
}
}
@@ -398,6 +399,7 @@
" brief process tag thread raw time threadtime long\n\n"
" -c clear (flush) the entire log and exit\n"
" -d dump the log and then exit (don't block)\n"
+ " -t <count> print only the most recent <count> lines (implies -d)\n"
" -g get the size of the log's ring buffer and exit\n"
" -b <buffer> request alternate ring buffer\n"
" ('main' (default), 'radio', 'events')\n"
@@ -472,7 +474,7 @@
for (;;) {
int ret;
- ret = getopt(argc, argv, "cdgsQf:r::n:v:b:B");
+ ret = getopt(argc, argv, "cdt:gsQf:r::n:v:b:B");
if (ret < 0) {
break;
@@ -493,6 +495,11 @@
g_nonblock = true;
break;
+ case 't':
+ g_nonblock = true;
+ g_tail_lines = atoi(optarg);
+ break;
+
case 'g':
getLogSize = 1;
break;