I am trying to understand fcntl system call , which has this structure as the second parameter:
struct flock fl;
int fd;
fl.l_type = F_WRLCK; /* F_RDLCK, F_WRLCK, F_UNLCK */
fl.l_whence = SEEK_SET; /* SEEK_SET, SEEK_CUR, SEEK_END */
fl.l_start = 0; /* Offset from l_whence */
fl.l_len = 0; /* length, 0 = to EOF */
fl.l_pid = getpid(); /* our PID
I want to know what exactly is fl.l_start
so for example if I make it fl.l_start = 5, does that mean that protection is guaranteed only beyond 5 bytes from the beginning?
(i.e before 5 bytes, no lock is there so, all the processes can have access to it in a non-cooperative manner.)
Related
I am new to writing functions in C to be used with SQL. So far, I have looked at this example which executes a query using SPI. However, it prints the result as a log message. I was wondering how would this example have to change for me to return the result as a normal query (normal as in how I can view it when I execute a SQL query in pgAdmin)?
User-defined functions written in C may be what you want. https://www.postgresql.org/docs/current/xfunc-c.html#id-1.8.3.13.11
A complete example of returning a composite type looks like:
PG_FUNCTION_INFO_V1(retcomposite);
Datum
retcomposite(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
int call_cntr;
int max_calls;
TupleDesc tupdesc;
AttInMetadata *attinmeta;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcontext;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/* switch to memory context appropriate for multiple function calls */
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* total number of tuples to be returned */
funcctx->max_calls = PG_GETARG_UINT32(0);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context "
"that cannot accept type record")));
/*
* generate attribute metadata needed later to produce tuples from raw
* C strings
*/
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
attinmeta = funcctx->attinmeta;
if (call_cntr < max_calls) /* do when there is more left to send */
{
char **values;
HeapTuple tuple;
Datum result;
/*
* Prepare a values array for building the returned tuple.
* This should be an array of C strings which will
* be processed later by the type input functions.
*/
values = (char **) palloc(3 * sizeof(char *));
values[0] = (char *) palloc(16 * sizeof(char));
values[1] = (char *) palloc(16 * sizeof(char));
values[2] = (char *) palloc(16 * sizeof(char));
snprintf(values[0], 16, "%d", 1 * PG_GETARG_INT32(1));
snprintf(values[1], 16, "%d", 2 * PG_GETARG_INT32(1));
snprintf(values[2], 16, "%d", 3 * PG_GETARG_INT32(1));
/* build a tuple */
tuple = BuildTupleFromCStrings(attinmeta, values);
/* make the tuple into a datum */
result = HeapTupleGetDatum(tuple);
/* clean up (this is not really necessary) */
pfree(values[0]);
pfree(values[1]);
pfree(values[2]);
pfree(values);
SRF_RETURN_NEXT(funcctx, result);
}
else /* do when there is no more left */
{
SRF_RETURN_DONE(funcctx);
}
}
You can combine this with SPI.
I'm trying to program LPC824 microcontroller board ([https://www.switch-science.com/catalog/2265/][1]) with LPCOpen.
I'm using it with LPCLink 2 debugger board.
My goal is to get some information from the "pressure sensor" with an ADC.
My code stops with a HardFault when executing a NVIC_EnableIRQ function(on line: 92).
If I don't use "NVIC interrupt controller" then my code works and I can get value from sensor with ADC.
What I am doing wrong?
Here is my adc.c code:
#include "board.h"
static volatile int ticks;
static bool sequenceComplete = false;
static bool thresholdCrossed = false;
#define TICKRATE_HZ (100) /* 100 ticks per second */
#define BOARD_ADC_CH 2
/**
* #brief Handle interrupt from ADC sequencer A
* #return Nothing
*/
void ADC_SEQA_IRQHandler(void) {
uint32_t pending;
/* Get pending interrupts */
pending = Chip_ADC_GetFlags(LPC_ADC);
/* Sequence A completion interrupt */
if (pending & ADC_FLAGS_SEQA_INT_MASK) {
sequenceComplete = true;
}
/* Threshold crossing interrupt on ADC input channel */
if (pending & ADC_FLAGS_THCMP_MASK(BOARD_ADC_CH)) {
thresholdCrossed = true;
}
/* Clear any pending interrupts */
Chip_ADC_ClearFlags(LPC_ADC, pending);
}
/**
* #brief Handle interrupt from SysTick timer
* #return Nothing
*/
void SysTick_Handler(void) {
static uint32_t count;
/* Every 1/2 second */
if (count++ == TICKRATE_HZ / 2) {
count = 0;
Chip_ADC_StartSequencer(LPC_ADC, ADC_SEQA_IDX);
}
}
/**
* #brief main routine for ADC example
* #return Function should not exit
*/
int main(void) {
uint32_t rawSample;
int j;
SystemCoreClockUpdate();
Board_Init();
/* Setup ADC for 12-bit mode and normal power */
Chip_ADC_Init(LPC_ADC, 0);
Chip_ADC_Init(LPC_ADC, ADC_CR_MODE10BIT);
/* Need to do a calibration after initialization and trim */
Chip_ADC_StartCalibration(LPC_ADC);
while (!(Chip_ADC_IsCalibrationDone(LPC_ADC))) {
}
/* Setup for maximum ADC clock rate using sycnchronous clocking */
Chip_ADC_SetClockRate(LPC_ADC, ADC_MAX_SAMPLE_RATE);
Chip_ADC_SetupSequencer(LPC_ADC, ADC_SEQA_IDX,
(ADC_SEQ_CTRL_CHANSEL(BOARD_ADC_CH) | ADC_SEQ_CTRL_MODE_EOS));
Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_SWM);
Chip_SWM_EnableFixedPin(SWM_FIXED_ADC2);
Chip_Clock_DisablePeriphClock(SYSCTL_CLOCK_SWM);
/* Setup threshold 0 low and high values to about 25% and 75% of max */
Chip_ADC_SetThrLowValue(LPC_ADC, 0, ((1 * 0xFFF) / 4));
Chip_ADC_SetThrHighValue(LPC_ADC, 0, ((3 * 0xFFF) / 4));
Chip_ADC_ClearFlags(LPC_ADC, Chip_ADC_GetFlags(LPC_ADC));
Chip_ADC_EnableInt(LPC_ADC,
(ADC_INTEN_SEQA_ENABLE | ADC_INTEN_OVRRUN_ENABLE));
Chip_ADC_SelectTH0Channels(LPC_ADC, ADC_THRSEL_CHAN_SEL_THR1(BOARD_ADC_CH));
Chip_ADC_SetThresholdInt(LPC_ADC, BOARD_ADC_CH, ADC_INTEN_THCMP_CROSSING);
/* Enable ADC NVIC interrupt */
NVIC_EnableIRQ(ADC_SEQA_IRQn);
Chip_ADC_EnableSequencer(LPC_ADC, ADC_SEQA_IDX);
SysTick_Config(SystemCoreClock / TICKRATE_HZ);
/* Endless loop */
while (1) {
/* Sleep until something happens */
__WFI();
if (thresholdCrossed) {
thresholdCrossed = false;
printf("********ADC threshold event********\r\n");
}
/* Is a conversion sequence complete? */
if (sequenceComplete) {
sequenceComplete = false;
/* Get raw sample data for channels 0-11 */
for (j = 0; j < 12; j++) {
rawSample = Chip_ADC_GetDataReg(LPC_ADC, j);
/* Show some ADC data */
if (rawSample & (ADC_DR_OVERRUN | ADC_SEQ_GDAT_DATAVALID)) {
printf("Chan: %d Val: %d\r\n", j, ADC_DR_RESULT(rawSample));
printf("Threshold range: 0x%x ",
ADC_DR_THCMPRANGE(rawSample));
printf("Threshold cross: 0x%x\r\n",
ADC_DR_THCMPCROSS(rawSample));
printf("Overrun: %s ",
(rawSample & ADC_DR_OVERRUN) ? "true" : "false");
printf("Data Valid: %s\r\n\r\n",
(rawSample & ADC_SEQ_GDAT_DATAVALID) ?
"true" : "false");
}
}
}
}
}
Hard fault usually means that you try to execute code outside allowed addresses. If you have not registered the interrupt in the vector table but enabled it, the MCU will jump to whatever address that's written there instead, after which the program crashes.
How to fix that depends on tool chain. Assuming LPCXpresso, you have several options to set up libraries (I don't know about LPCOpen specifically), so where to find the vector table is different from case to case. However, this works quite similar on most MCUs, ARM or not. Somewhere in a "crt start-up" file you should have something along the lines of this:
void (* const g_pfnVectors[])(void) = ...
This is an array of function pointers which will be the vector table allocated in memory at address 0 on Cortex M. You have to place your function at the relevant interrupt vector. For example it may say something like
PIN_INT0_IRQHandler, // PIO INT0
If that's the interrupt you should implement, then you replace that line:
#include "my_irq_stuff.h"
...
void (* const g_pfnVectors[])(void) =
...
my_INT0, // PIO INT0
Assuming my_irq_stuff.h contains the function prototype my_INT0 for the interrupt service routine. The actual routine should be implemented in the corresponding .c file.
I am using PIC32MX350F128L Microcontroller to read from and write to EEPROM(SST26VF032B) using SPI communication. SPI communication in this program is working, I have checked it by sending JEDEC code which is provided in the SST26VF032B datasheet. So when i send 0x9F i am getting 3 bytes of data as mentioned in the datasheet. When i run now i am sending a string of data to a specific address of eeprom and getting 0xff in return. I am erasing the eeprom before writing into it. So i think i am getting 0xff after erasing the eeprom. The writing, reading operations are not working. If i send a string of value or a BYTE i am getting 0xff in return. So can u guys please suggest me where i am going wrong. I am using UART for debugging purpose to read values recieved through spi communication. The complete code is below, i am using MPLAB X.
Best Regards
Sandesh
#include <xc.h>
#include <stdio.h>
#include <plib.h>
#include <p32xxxx.h>
/* Configuration Bits */
#pragma config FSRSSEL = PRIORITY_7 // Shadow Register Set Priority Select (SRS Priority 7)
#pragma config PMDL1WAY = ON // Peripheral Module Disable Configuration (Allow only one reconfiguration)
#pragma config IOL1WAY = ON // Peripheral Pin Select Configuration (Allow only one reconfiguration)
// DEVCFG2
#pragma config FPLLIDIV = DIV_2 // PLL Input Divider (2x Divider)
#pragma config FPLLMUL = MUL_20 // PLL Multiplier (20x Multiplier)
#pragma config FPLLODIV = DIV_1 // System PLL Output Clock Divider (PLL Divide by 1)
// DEVCFG1
#pragma config FNOSC = PRIPLL // Oscillator Selection Bits (Primary Osc (XT,HS,EC))
#pragma config FSOSCEN = ON // Secondary Oscillator Enable (Enabled)
#pragma config IESO = ON // Internal/External Switch Over (Enabled)
#pragma config POSCMOD = HS // Primary Oscillator Configuration (XT osc mode)
#pragma config OSCIOFNC = ON // CLKO Output Signal Active on the OSCO Pin (Enabled)
#pragma config FPBDIV = DIV_1 // Peripheral Clock Divisor (Pb_Clk is Sys_Clk/8)
#pragma config FCKSM = CSECME // Clock Switching and Monitor Selection (Clock Switch Disable, FSCM Disabled)
#pragma config WDTPS = PS1048576 // Watchdog Timer Postscaler (1:1048576)
#pragma config WINDIS = OFF // Watchdog Timer Window Enable (Watchdog Timer is in Non-Window Mode)
#pragma config FWDTEN = OFF // Watchdog Timer Enable (WDT Disabled (SWDTEN Bit Controls))
#pragma config FWDTWINSZ = WINSZ_25 // Watchdog Timer Window Size (Window Size is 25%)
// DEVCFG0
#pragma config DEBUG = OFF // Background Debugger Enable (Debugger is Disabled)
#pragma config JTAGEN = OFF // JTAG Enable (JTAG Disabled)
#pragma config ICESEL = ICS_PGx2 // ICE/ICD Comm Channel Select (Communicate on PGEC2/PGED2)
#pragma config PWP = OFF // Program Flash Write Protect (Disable)
#pragma config BWP = OFF // Boot Flash Write Protect bit (Protection Disabled)
#pragma config CP = OFF // Code Protect (Protection Disabled)
/* MACRO DEFINITIONS */
/* Defining the Slave Select Pin */
#define SS LATDbits.LATD9
/* Defining the System Clock Frequency */
#define SYSCLK 40000000
/* Macro to get array size in bytes
* note that array size can't be found after passing pointer to a function */
#define LEN(x) (sizeof(x) / sizeof(x[0]))
/* SST26VF032B EEPROM instructions */
/* Write Enable */
#define WREN 0x06
/* Write Disable */
#define WRDI 0x04
/* Initialize Start of Write Sequence */
#define WRITE 0x02
/* Initialize Start of Read Sequence */
#define READ 0x03
/* Erase all sectors of Memory */
#define CE 0xc7
/* Read STATUS Register */
#define RDSR 0x05
/* Function Prototypes */
/* UART bit configuration */
void Bitconfig_uart(void);
/* SPI Initialization */
void SPI1_Init(void);
/* UART Initialization */
void Init_uart(void);
/* Send a Character Byte through UART */
void UART5PutChar(char Ch);
/* Function to Read and Write SPI1 buffer */
int SPI1_transfer( int b);
/* Function to check the Status of SPI */
void waitBusy();
/* Function to erase the contents in EEPROM */
void eraseEEPROM();
/* Function to Read data from EEPROM */
void readEEPROM( int address, char* loadArray, int loadArray_size);
/* Function to Write to EEPROM */
void writeEEPROM( int address, char* storeArray, int storeArray_size);
/* Global Variables Declaration */
/* Declare variables to check the functionality of EEPROM */
int i,j = 0;
char st = 0x9F;
char rec;
int x,y,z;
/*******************************************************************************
* Function Name: main()
********************************************************************************
* Summary:
* Initializes SPI
* Erase EEPROM
* Writes to EEPROM
* Read from EEPROM
*
* Parameters:
* None.
*
* Return:
* None.
*
*******************************************************************************/
int main()
{
int i;
/* Clock Setting */
SYSTEMConfigPerformance(SYSCLK);
/* UART bit configuration */
Bitconfig_uart();
/* Set the Controller OScillator Register bits */
//OSCCON = 0x00002200;
/* Initialize a String to Write to EEPROM and an array to Read back contents */
char writeData[] = "123456789ABCDEF";
/* Array to read 35 bytes of data */
char readData[15];
/* SPI Initialization */
SPI1_Init();
/* UART Initialization */
Init_uart();
/* Erase contents of EEPROM */
eraseEEPROM();
/* Write contents of writeData array to address 180 */
writeEEPROM( 0x1000, writeData, LEN(writeData));
/*
JEDEC Code (working) getting output as per datasheet (0x9F = 159)
SS=0;
SPI1_transfer(159);
x=SPI1_transfer(0);
UART5PutChar(x);
y=SPI1_transfer(0);
UART5PutChar(y);
z=SPI1_transfer(0);
UART5PutChar(z);
*/
while(1)
{
/* Read contents of EEPROM into readData array
* start at address 180 and read up to 180+length(readData) */
readEEPROM( 0x1000, readData, LEN(readData) );
}
} /* END main() */
/*******************************************************************************
* Function Name: SPI1_Init()
********************************************************************************
* Summary:
* SPI1 Initialization
*
* Parameters:
* None.
*
* Return:
* None.
*
*******************************************************************************/
void SPI1_Init(void)
{
/* Configure Peripheral Pin Select (PPS) for the SPI1 module
* Note: SS will be toggled manually in code
* SCK is hardwired to pin 55 */
/* Output Pin Selection */
RPE5R = 8;
SDI1R = 3;
/* RB4 (Slave Select 1) : output */
TRISDbits.TRISD9 = 0;
/* SPI configuration */
/* SPI1CON Register Configuration
* MSTEN: Master Mode Enable bit = 1 (Master)
* CKP (clock polarity control) = 0
* CKE (clock edge control) = 1
* ON: SPI Peripheral On bit
* 8-bit, Master Mode */
SPI1CON = 0x8120;
/* SPI1BRG Register Configuration */
SPI1BRG = 0x4D;
//REFOCONbits.ON = 1;
// REFOCONbits.DIVSWEN = 1;
}
/*******************************************************************************
* Function Name: SPI1_transfer()
********************************************************************************
* Summary:
* Write to and Read from SPI1 buffer
*
* Parameters:
* char b - Writes a Character to Buffer
*
* Return:
* Char - Returns the Character Read from EEPROM
*
*******************************************************************************/
int SPI1_transfer( int b)
{
/* write to buffer for TX */
SPI1BUF = b;
/* wait transfer complete */
while(!SPI1STATbits.SPIRBF);
/* read the received value */
return SPI1BUF;
} /* END SPI1_transfer() */
/*******************************************************************************
* Function Name: waitBusy()
********************************************************************************
* Summary:
* Checks if EEPROM is ready to be modified and waits if not ready
*
* Parameters:
* None.
*
* Return:
* None.
*
*******************************************************************************/
void waitBusy()
{
char status = 0;
do{
/* Select EEPROM */
SS = 0;
/* Read EEPROM status register */
SPI1_transfer(RDSR);
/* send dummy byte to receive incoming data */
status = SPI1_transfer(0);
/* Release EEPROM */
SS = 1;
}
/* write-in-progress while status<0> set to '1' */
while( status & 0x01);
} /* END waitBusy() */
/*******************************************************************************
* Function Name: readEEPROM()
********************************************************************************
* Summary:
* Reads data from EEPROM
*
* Parameters:
* Inputs: address - EEPROM address
* loadArray - array to load EEPROM data to
* loadArray_size - number of bytes of EEPROM data to load into array
*
* Return:
* None.
*
*******************************************************************************/
void readEEPROM( int address, char* loadArray, int loadArray_size)
{
int i;
/* Wait until EEPROM is not busy */
waitBusy();
/* Select EEPROM */
SS = 0;
/* Initiate Read */
SPI1_transfer( READ);
/* Address must be 16-bits but we're transferring it in two 8-bit sessions */
SPI1_transfer( address >> 16);
SPI1_transfer( address >> 8);
SPI1_transfer( address);
/* Request and store loadArray_size number of bytes into loadArray */
for( i=0 ; i<loadArray_size ; i++)
{
/* send dummy byte to read 1 byte */
loadArray[i] = SPI1_transfer( 0x00);
}
/* Release EEPROM */
SS = 1;
/* UART Test */
for(i=0;i<35;i++)
{
UART5PutChar(loadArray[i]);
for(j=0;j<20000;j++)
{}
}
} /* END readEEPROM() */
/*******************************************************************************
* Function Name: writeEEPROM()
********************************************************************************
* Summary:
* Write data to EEPROM
*
* Parameters:
* Inputs: address - EEPROM address
* storeArray - array of which contents are stored in EEPROM
* storeArray_size - number of bytes in array to store into EEPROM
*
* Return:
* None.
*
*******************************************************************************/
void writeEEPROM( int address, char* storeArray, int storeArray_size)
{
int i;
/* Wait until EEPROM is not busy */
waitBusy();
/* Select EEPROM */
SS = 0;
/* Send WRITE_ENABLE command */
SPI1_transfer( WREN);
/* Release EEPROM */
SS = 1;
/* Select EEPROM again after WREN cmd */
SS = 0;
/* Initiate Write */
SPI1_transfer( WRITE);
SPI1_transfer( address >> 16 );
SPI1_transfer( address >> 8 );
SPI1_transfer( address );
/* write 1 byte at a time from array */
/* MSB at lowest address (0 - first letter in string) */
for( i=0 ; i<storeArray_size; i++)
{
/* Initiate Write */
SPI1_transfer( WRITE);
SPI1_transfer( (address+i) >> 16 );
SPI1_transfer( (address+i) >> 8 );
SPI1_transfer( address+i );
SPI1_transfer( storeArray[i]);
}
/* Release EEPROM */
SS = 1;
} /* END writeEEPROM() */
/*******************************************************************************
* Function Name: eraseEEPROM()
********************************************************************************
* Summary:
* Erase entire contents of EEPROM
*
* Parameters:
* None
*
* Return:
* None.
*
*******************************************************************************/
void eraseEEPROM()
{
/* Wait until EEPROM is not busy */
waitBusy();
/* Select EEPROM */
SS = 0;
/* Send WRITE_ENABLE command */
SPI1_transfer( WREN);
/* Release EEPROM */
SS = 1;
/* Select EEPROM again after WREN cmd */
SS = 0;
/* send CHIP_ERASE command */
SPI1_transfer( CE);
/* Release EEPROM */
SS = 1;
} /* END eraseEEPROM() */
/*******************************************************************************
* Function Name: Init_uart()
********************************************g************************************
* Summary:
* Initialize UART4
*
* Parameters:
* None
*
* Return:
* None.
*
*******************************************************************************/
void Init_uart()
{
/* Enable UART */
U5MODEbits.ON = 1 ;
/* set baud rate(9600) */
U5BRG = 521;
/* Set U4STA Register for Enabling tx and rx */
U5STA=0x9400;
}
/*******************************************************************************
* Function Name: UART4PutChar(unsigned char Ch)
********************************************************************************
* Summary:
* Send data from controller to putty GUI
*
* Parameters:
* input
* unsigned char Ch - To Send a byte of data over UART
*
* Return:
* None.
*
*******************************************************************************/
void UART5PutChar(char Ch)
{
while(U5STAbits.UTXBF == 1);
U5TXREG=Ch;
}
/*******************************************************************************
* Function Name: Bitconfig_uart()
********************************************************************************
* Summary:
* UART Pin Configuration
*
* Parameters:
* None
*
* Return:
* None.
*
*******************************************************************************/
void Bitconfig_uart(void)
{
/* UART4 Initialization */
// OSCCON=0x00002200;
/* Set pins as digital */
ANSELBbits.ANSB2 = 0;
ANSELBbits.ANSB0 = 0;
/* Set UART Tx pin as Output */
TRISBbits.TRISB0 = 0; //in controler tx
TRISBbits.TRISB2 = 1; // in controller RX
/* Peripheral Pin select for UART4 */
U5RXR=0x07;
RPB0R=0x04;
}
I faced the same problem for 3 long days until I found that there's a 18bytes long register called Block Protection Register BPR.
You need to set its bits to 0, according to the memory area you want to write.
So I read the BPR (send command 0x72 followed by 18 byte read) and I found it was not at zero everywhere in my case.
Reading on page 41 of the datasheet you can see that after a power on the BPR register is set to 5555 FFFFFFFF FFFFFFFF, so it protects from write the whole memory.
So for testing purpose I tried to clears it completely, and there's a specific command (0x98) for that purpose, allowing you to write anywhere in the whole memory.
But be sure to write enable the memory (command 0x06) before sending the clear BPR command (command 0x98).
At this point if you read the BPR (command 0x72) you will read 00 at every of its 10 bytes. (And this means the whole memory is now writeable)
In this state the write now finally works for me.
(I sent WriteEnable - SectorErase - SectorRead - WriteEnable - SectorWrite - SectorRead and it now works!)
Hope it helps, the datasheet is very chaotic about that.
P.S.
Somewhere the datasheet says that BPR is 18 bytes long, it is wrong, the BPR is only 10 bytes long
I am on OSX Mountain Lion and am trying to retrieve a processes' name using its PID.
The following is the code I am using:
pid_t pid = 10687;
char pathBuffer [PROC_PIDPATHINFO_MAXSIZE] = "";
char nameBuffer [256] = "";
int sizeOfVal = sizeof(nameBuffer);
proc_pidpath(pid, pathBuffer, sizeof(pathBuffer));
proc_name(pid, nameBuffer, sizeof(nameBuffer));
NSLog(#"Path: %s\n Name: %s\n", pathBuffer, nameBuffer);
The code above is able to retrieve the name properly, however it only retrieves the first 15 characters and "ignores" the rest. Note this is not a problem with displaying the name, but with retrieving it. The problem is not with the rest of my application as I am testing the above code in a standalone application. Also note that I tried changing the PID, but regardless of what PID I try the code only retrieves the first 15 characters of the name. Path retrieval works perfectly.
Does anyone have any ideas about what I am doing wrong?
The function looks at the value is the struct proc_bsdshortinfo. It is limited to return a 16 byte string, or 15 readable characters when including the null terminator.
From sys/param.h:
#define MAXCOMLEN 16 /* max command name remembered */
From sys/proc_info.h:
struct proc_bsdshortinfo {
uint32_t pbsi_pid; /* process id */
uint32_t pbsi_ppid; /* process parent id */
uint32_t pbsi_pgid; /* process perp id */
uint32_t pbsi_status; /* p_stat value, SZOMB, SRUN, etc */
char pbsi_comm[MAXCOMLEN]; /* upto 16 characters of process name */
uint32_t pbsi_flags; /* 64bit; emulated etc */
uid_t pbsi_uid; /* current uid on process */
gid_t pbsi_gid; /* current gid on process */
uid_t pbsi_ruid; /* current ruid on process */
gid_t pbsi_rgid; /* current tgid on process */
uid_t pbsi_svuid; /* current svuid on process */
gid_t pbsi_svgid; /* current svgid on process */
uint32_t pbsi_rfu; /* reserved for future use*/
};
EDIT: To get around this, get the last path component:
pid_t pid = 3051;
char pathBuffer [PROC_PIDPATHINFO_MAXSIZE];
proc_pidpath(pid, pathBuffer, sizeof(pathBuffer));
char nameBuffer[256];
int position = strlen(pathBuffer);
while(position >= 0 && pathBuffer[position] != '/')
{
position--;
}
strcpy(nameBuffer, pathBuffer + position + 1);
printf("path: %s\n\nname:%s\n\n", pathBuffer, nameBuffer);
I've managed to implement the code on this listing to get a list of all the processes running and their IDs. What I need now is to extract how much time each process uses the CPU.
I've tried referring to the keys in the code, but when I try to print 'Ticks of CPU Time' I get a zero value for all of the processes. Plus, even if I did get a value I'm not sure if 'Ticks of CPU Time' is exactly what I'm looking for.
struct vmspace *p_vmspace; /* Address space. */
struct sigacts *p_sigacts; /* Signal actions, state (PROC ONLY). */
int p_flag; /* P_* flags. */
char p_stat; /* S* process status. */
pid_t p_pid; /* Process identifier. */
pid_t p_oppid; /* Save parent pid during ptrace. XXX */
int p_dupfd; /* Sideways return value from fdopen. XXX */
/* Mach related */
caddr_t user_stack; /* where user stack was allocated */
void *exit_thread; /* XXX Which thread is exiting? */
int p_debugger; /* allow to debug */
boolean_t sigwait; /* indication to suspend */
/* scheduling */
u_int p_estcpu; /* Time averaged value of p_cpticks. */
int p_cpticks; /* Ticks of cpu time. */
fixpt_t p_pctcpu; /* %cpu for this process during p_swtime */
void *p_wchan; /* Sleep address. */
char *p_wmesg; /* Reason for sleep. */
u_int p_swtime; /* Time swapped in or out. */
u_int p_slptime; /* Time since last blocked. */
struct itimerval p_realtimer; /* Alarm timer. */
struct timeval p_rtime; /* Real time. */
u_quad_t p_uticks; /* Statclock hits in user mode. */
u_quad_t p_sticks; /* Statclock hits in system mode. */
u_quad_t p_iticks; /* Statclock hits processing intr. */
int p_traceflag; /* Kernel trace points. */
struct vnode *p_tracep; /* Trace to vnode. */
int p_siglist; /* DEPRECATED */
struct vnode *p_textvp; /* Vnode of executable. */
int p_holdcnt; /* If non-zero, don't swap. */
sigset_t p_sigmask; /* DEPRECATED. */
sigset_t p_sigignore; /* Signals being ignored. */
sigset_t p_sigcatch; /* Signals being caught by user. */
u_char p_priority; /* Process priority. */
u_char p_usrpri; /* User-priority based on p_cpu and p_nice. */
char p_nice; /* Process "nice" value. */
char p_comm[MAXCOMLEN+1];
struct pgrp *p_pgrp; /* Pointer to process group. */
struct user *p_addr; /* Kernel virtual addr of u-area (PROC ONLY). */
u_short p_xstat; /* Exit status for wait; also stop signal. */
u_short p_acflag; /* Accounting flags. */
struct rusage *p_ru; /* Exit information. XXX */
In fact I've also tried to print Time averaged value of p_cpticks and a few others and never got interesting values. Here is my code which is printing the information retrieved (I got it from cocoabuilder.com) :
- (NSDictionary *) getProcessList {
NSMutableDictionary *ProcList = [[NSMutableDictionary alloc] init];
kinfo_proc *mylist;
size_t mycount = 0;
mylist = (kinfo_proc *)malloc(sizeof(kinfo_proc));
GetBSDProcessList(&mylist, &mycount);
printf("There are %d processes.\n", (int)mycount);
NSLog(#" = = = = = = = = = = = = = = =");
int k;
for(k = 0; k < mycount; k++) {
kinfo_proc *proc = NULL;
proc = &mylist[k];
// NSString *processName = [NSString stringWithFormat: #"%s",proc->kp_proc.p_comm];
//[ ProcList setObject: processName forKey: processName ];
// [ ProcList setObject: proc->kp_proc.p_pid forKey: processName];
// printf("ID: %d - NAME: %s\n", proc->kp_proc.p_pid, proc->kp_proc.p_comm);
printf("ID: %d - NAME: %s CPU TIME: %d \n", proc->kp_proc.p_pid, proc->kp_proc.p_comm, proc->kp_proc.p_pid );
// Right click on p_comm and select 'jump to definition' to find other values.
}
free(mylist);
return [ProcList autorelease];
}
Thanks!
EDIT: I've just offered a bounty for this question. What I'm looking for specifically is to get the amount of time each process spends in CPU.
If, in addition to this, you can give %CPU being used by a process, that would be fantastic.
The code should be optimal in that it will be called every second and the method will be called on all running processes. Objective-C preferable.
Thanks again!
EDIT 2
Also, any comments as to why people are ignoring this question would also be helpful :)
Have a look at the Darwin source for libtop.c and particularly the libtop_pinfo_update_cpu_usage() function. Note that:
You'll need a basic understanding of Mach programming fundamentals to make sense of this code, as it uses task ports, etc.
If you want to simply use libtop, you'll have to download the source and compile it yourself.
Your process will need privileges to get at the task ports for other processes.
If all this sounds rather daunting, well… There is a way that uses less esoteric APIs: Just spawn a top process and parse its standard output. A quick glimpse over the top(1) man page turned up this little gem:
$ top -s 1 -l 3600 -stats pid,cpu,time
That is, sample once per second for 3600 seconds (one hour), and output to stdout in log form only the statistics for pid, cpu usage, and time.
Spawning and managing the child top process and then parsing its output are all straightforward Unix programming exercises.
Have you taken a look at the struct rusage? You have listed it and commented as "Exit information" but I know that it contains the resources actually used by a process. Take a look at this page. I remember I used getrusage() for calculating the exact amount of CPU time used in my scientific calculation for my current process, so you just have to know how to query that struct for each process in you list i guess