Applets that display directories
Show applets that specify directories:
#include <unistd.h>
#include <stdio.h>
#include <dirent.h>
#include <string.h>
#include <sys/stat.h>
# include <stdlib.h>
void printdir(char *dir,int depth){ DIR *dp; struct dirent *entry; struct stat statbuf; if((dp = opendir(dir)) == NULL){ fprintf(stderr, " cannot open directory: %s\n", dir); return; } chdir(dir); while((entry = readdir(dp)) != NULL){ lstat(entry->d_name,&statbuf); if(S_ISDIR( statbuf.st_mode)){ /*Found a directory, but ignore . and ..*/
if(strcmp(".",entry->d_name) == 0 || strcmp("..",entry->d_name) == 0){
continue;
}
printf("%*s%s/ \n",depth,"",entry->d_name);
/*Recurse at a new indent level*/
printdir(entry->d_name,depth+4);
}else{
printf("%*s%s \n",depth,"",entry->d_name);
}
}
}
int main(){
/*
show directory
*/
printf("Directory scan of /home:\n");
printdir("/home",0);
printf("done. \n");
exit(0);
}
根据参数输出目录的结构
#include <unistd.h>
#include <stdio.h>
#include <dirent.h>
#include <string.h>
#include <sys/stat.h>
#include <stdlib.h>
void printdir(char *dir,int depth){
DIR *dp;
struct dirent *entry;
struct stat statbuf;
if((dp = opendir(dir)) == NULL){
fprintf(stderr, "cannot open directory: %s\n", dir);
return;
}
chdir(dir);
while((entry = readdir(dp)) != NULL){
lstat(entry->d_name,&statbuf);
if(S_ISDIR(statbuf.st_mode)){
/*Found a directory,but ignore . and ..*/
if(strcmp(".",entry->d_name) == 0 || strcmp("..",entry->d_name) == 0){
continue;
}
printf("%*s%s/ \n",depth,"",entry->d_name); /
*Recurse at a new indent level*/
printdir(entry->d_name,depth+4);
}else{ printf ("%*s%s \n",depth,"",entry->d_name); } } } int main ( int argc, char* argv[]){ /* show directory */ char *topdir = ". "; if(argc >= 2){ topdir = argv[1]; } printf("Directory scan of %s:\n",topdir); printdir(topdir,0); printf("done.\n") ; exit(0); } Get basic host information Get host user information: #include <sys/types.h> #include <pwd.h> #include <stdio.h>
#include <unistd.h>
int main(){
uid_t uid;
gid_t gid;
struct passwd *pw;
uid = getuid();
gid = getgid();
printf("User is %s\n",getlogin());
printf("User IDs: uid=%d, gid=%d \n", uid, gid);
pw = getpwuid(uid);
printf("UID passwd entry: \n name=%s, uid=%d, gid=%d, home=%s, shell=%s\n",pw->pw_name, pw->pw_uid, pw->pw_gid, pw->pw_dir, pw->pw_shell);
pw = getpwnam("root");
printf("root passwd entry: \n");
printf("name=%s, uid=%d, gid=%d, home=%s, shell=%s \n",pw->pw_name, pw->pw_uid, pw->pw_gid, pw->pw_dir, pw->pw_shell);
exit(0);
}
获取主机自身信息:
#include <sys/utsname.h>
#include <unistd.h>
#include <stdio.h>
int main(){
char computer[256];
struct utsname uts;
if(gethostname(computer, 255) != 0 || uname(&uts) < 0){
fprintf(stderr, "Could not get host information \n");
exit(1);
}
printf("Computer host name is %s \n",computer);
printf("System is %s on %s hardware \n",uts.sysname, uts.machine);
printf("Nodename is %s \n",uts.nodename);
printf("Version is %s , %s \n",uts.release, uts.version);
exit(0);
}
#include <sys/utsname.h>
#include <unistd.h>
#include <stdio.h>
int main(){
char computer[256];
struct utsname uts;
if(gethostname(computer, 255) != 0 || uname(&uts) < 0){
fprintf(stderr, "Could not get host information \n");
exit(1);
}
printf("Computer host name is %s \n",computer);
printf("System is %s on %s hardware \n",uts.sysname, uts.machine);
printf("Nodename is %s \n",uts.nodename);
printf("Version is %s , %s \n",uts.release, uts.version);
exit(0);
}
Get system memory, cpu, hard disk and other information
#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
void sampleLoadAvg(){ int f=0; char buffer[80]=""; /* 定义字符串并初始化为'\0' */ char buf[5][10]; char *file="/proc/loadavg"; f = open(file, O_RDONLY); if (f == 0) { printf("error to open: %s\n", file); exit(EXIT_FAILURE); } read(f, (void *)buffer, 80); sscanf(buffer, "%s %s %s %s %s", /* sscanf() split into multiple strings*/
&buf[0],&buf[1],&buf[2],&buf[3],&buf[4]); printf("One minute average load: %s\n", buf[0]); printf(
"
5 Minute average load: %s\n", buf[1]);
printf("A quarter of an hour average load: %s\n", buf[2]);
printf("Sampling time interval: %s\n", buf[3]);
printf("The maximum number of threads: %s\n", buf[4]);
close(f);
}
void sampleTime(){ int f=0; char buffer[80]="" ; char buf[2][10]; float seconds=0; float secondr=0; char *file="/proc/uptime"; f = open(file, O_RDONLY); if (f == 0) { printf( "error to open: %s\n", file); exit(EXIT_FAILURE); } read(f, (void *)buffer, 80);
sscanf(buffer, "%s %s", &buf[0], &buf[1]);
close(f);
printf("System running time: \t%s seconds\n", buf[0]);
printf ("System idle time: \t%s seconds\n", buf[1]);
close(f);
seconds=strtof(buf[0],NULL);
secondr=strtof(buf[1],NULL);
printf("System running time:\t%03dday%02dhour%02dminute%02.6fsecond\n",
(int)seconds/(24*3600), /*day*/
((int)seconds/(3600 ))%(24), /* hours*/
((int)seconds/60)%60, /* minutes*/
((int)seconds%60)+(seconds-(int)seconds)); /* seconds (accurate to milliseconds) */
printf("System idle time: \t%03d days %02d hours %02d minutes %02.6f seconds\n", (
int)secondr/(24*3600), /* days*/
( (int)secondr/(3600))%(24),/* hour*/
((int)secondr/60)%60, /* minute*/
((int)secondr%60)+(secondr-(int)secondr)); /* second (accurate to millisecond) */ }
void
sampleKernelVersion() { int f=0; char buffer[80]=""; char *file="/proc/sys/kernel/version"; f = open(file, O_RDONLY); if (f == 0) { printf(" error to open: %s\n", file); exit(EXIT_FAILURE); } read(f, (void *)buffer, 80); buffer[strlen(buffer)-1]=0; /* Simple implementation of tr( ) function */ printf("current kernel version:\t%s\n", buffer); close(f); } void sampleOsRelease(){ int f=0;
char buffer[80]="";
char *file="/proc/sys/kernel/osrelease";
f = open(file, O_RDONLY);
if (f == 0)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
read(f, (void *)buffer, 80);
buffer[strlen(buffer)-1]=0;
printf("当前发行版本：\t%s\n", buffer);
close(f);
}
void sampleOsType(){
int f=0;
char buffer[80]="";
char *file="/proc/sys/kernel/ostype";
f = open(file, O_RDONLY);
if (f == 0)
{
printf("error to open: %s\n", file);
exit(EXIT_FAILURE);
}
read(f, (void *)buffer, 80);
buffer[strlen(buffer)-1]=0;
printf("Current operating system:\t%s\n", buffer);
close(f);
}
void sampleDiskStat(){ int i; FILE *fp; int nread=0; ssize_t len = 0; char *buffer=NULL; char buf[20][32]; char *file="/proc/diskstats"; char *p ; fp = fopen(file, "rb"); if (fp == NULL) { printf("error to open: %s\n", file); exit(EXIT_FAILURE); } printf(" Disk read and write times \n"); while((nread = getline(&buffer, &len, fp)) != -1) { /* simply realize the function of reading lines*/
sscanf(buffer, "%04s%08s%s %s %s %s %s %s %s %s %s %s %s %s",
&buf[0],&buf[1],&buf[2],&buf[3],&buf[4],&buf[5],&buf[6],
&buf[7],&buf[8],&buf[9],&buf[10],&buf[11],&buf[12],&buf[13]);
if ((p=strstr(buf[2], "loop"))!=NULL)
{
; /* loop本地回路不作操作 */
}
else {
printf("%06s%08s%08s\n",
&buf[2],&buf[3], &buf[7]);
}
}
}
void sampleProcesses(void)
{
FILE *fp;
int nread=0;
ssize_t len = 0;
char *buf=NULL;
char *buffer=NULL;
char *file="/proc/stat";
fp = fopen(file, "rb");
if (fp == NULL)
{ printf("error to open: %s\n", file); exit(EXIT_FAILURE) ; } while((nread = getline(&buffer, &len, fp)) != -1) { if((buf=strstr(buffer, "processes"))!=NULL) /* simply realize the function of grep*/ break ; } buffer[strlen(buffer)-1]=0; /* Simple implementation of tr() function*/ char count[16]=""; sscanf(buffer, "%s%s", count, count) ; printf("Number of execution threads:\t%s\n", count); } void sampleContext(void) { FILE *fp; int nread=0; ssize_t len = 0;
char *buf=NULL;
char *buffer=NULL;
char *file="/proc/stat";
fp = fopen(file, "rb");
if (fp == NULL)
{ printf("error to open: % s\n", file); exit(EXIT_FAILURE); } while((nread = getline(&buffer, &len, fp)) != -1) { if((buf=strstr(buffer, "ctxt"))!= NULL) /* Simple implementation of grep function */ break; } buffer[strlen(buffer)-1]=0; /* Simple implementation of tr() function */ char count[16]=""; sscanf(buffer , "%s%s", count, count); printf("Number of context switches:\t%s\n", count); } void sampleMeminfo() { FILE *fp;
int nread=0;
ssize_t len = 0;
char *buf=NULL;
char *buffer=NULL;
char *file="/proc/meminfo";
char content[16]="";
fp = fopen(file, "rb ");
if (fp == NULL)
{ printf("error to open: %s\n", file); exit(EXIT_FAILURE); } while((nread = getline(&buffer, &len, fp)) != - 1) { if((buf=strstr(buffer, "MemTotal"))!=NULL) /* Simple implementation of grep function */ { buffer [strlen(buffer)-1]=0; /* Simple implementation of tr() The function of the function */ sscanf(buffer, "%s%s", content, content); int memtotal_kb=(int)(strtof(content,NULL));
printf("Total memory capacity:\t%dG%4dM %4dK\n",
memtotal_kb/(1024*1024), /* Gb */
(memtotal_kb/(1024))%1024, /* Mb */
(memtotal_kb% (1024*1024))%1024); /* Kb */
}
if((buf=strstr(buffer, "MemFree"))!=NULL) /* simple grep function*/ {
buffer [strlen(buffer) -1]=0; /* Simple implementation of tr() function*/ sscanf(buffer, "%s%s", content, content); int memfree_kb=(int)(strtof(content, NULL)); printf ("Memory available capacity:\t%dG%4dM %4dK\n", memfree_kb/(1024*1024), /* Gb */ (memfree_kb/(1024))%1024, /* Mb */
(memfree_kb%(1024*1024))%1024); /* Kb */
}
if((buf=strstr(buffer, "SwapTotal"))!=NULL) /* simply realize the function of grep*/ {
buffer [strlen (buffer)-1]=0; /* Simple implementation of tr() function*/ sscanf(buffer, "%s%s", content, content); int swaptotal_kb=(int)(strtof(content, NULL) ); printf("Total SWAP capacity:\t%dG%4dM %4dK\n", swaptotal_kb/(1024*1024), /* Gb */ (swaptotal_kb/(1024))%1024, /* Mb */ ( swaptotal_kb%(1024*1024))%1024); /* Kb */ } if((buf=strstr(buffer, "SwapFree"))!=NULL) /* simply realize the function of grep*/ {
buffer[strlen(buffer)-1]=0; /* Simple implementation of tr() function */
sscanf(buffer, "%s%s", content, content);
int swapfree_kb=(int)(strtof(content , NULL));
printf("SWAP available capacity:\t%dG%4dM %4dK\n",
swapfree_kb/(1024*1024), /* Gb */
(swapfree_kb/(1024))%1024, /* Mb */
(swapfree_kb%(1024*1024))%1024); /* Kb */
break; /* The required information has been satisfied, exit the loop */
}
}
}
/*
* === FUNCTION ===== ==================================================== ================
* Name: main
* Description:
* ==================================================== =========================================
*/
int main ( int argc, char *argv[] )
{ printf(">>>System Load<<<\n"); sampleLoadAvg(); printf("-------------------------- --------------\n"); printf("\n"); printf(">>>runtime<<<\n"); sampleTime(); printf(" \n"); printf(">>>Version Information<<<\n"); sampleOsType(); sampleOsRelease(); sampleKernelVersion(); printf("------------- --------------------------\n"); printf("\n"); printf(">>>Disk information<<<\n"); sampleDiskStat();
printf("----------------------------------------\n");
printf( "\n");
printf(">>>Context switching<<<\n");
sampleContext();
printf("--------------------- -------------------\n");
printf("\n");
printf(">>>thread number<<<\n");
sampleProcesses( );
printf("-------------------------------------------\n");
printf("\n");
printf(">>>Memory Information<<<\n");
sampleMeminfo();
printf("------------------- ---------------------\n");
return EXIT_SUCCESS;
}