Linux下获取当前进程的执行文件的绝对路径和所在目录(通过/proc/self/exe链接)

#include <stdio.h>
#include <string.h> 　　//strrchr(), strncpy()
#include <stdlib.h> 　 //realloc()
#include <unistd.h> //readlink()

#define MAXBUFSIZE 1024

//通过链接文件名获取被目标文件绝对路径
//为了防止buffer不够大，包装一下readlink()
char* getFilePathByLink(const char *filename)
{
int size = 100;
char *buffer = NULL;

while(1)
{
buffer = (char *) realloc(buffer, size);
//readlink()返回的路径名并没有以'\0'结尾
int nchars = readlink(filename, buffer, size - 1);
if (nchars < 0)
{
free(buffer);
return NULL;
}
if (nchars <= size - 1) {
buffer[nchars] = '\0'; //让路径名以'\0'结尾
return buffer;
}
size *= 2; //buffer空间不足，扩大为2倍
}
}

//通过链接文件名获取被目标文件所在目录
char* getFileDirByLink(const char *linkfile)
{
char* pathbuf = NULL;
pathbuf = getFilePathByLink(linkfile);
if (NULL == pathbuf) {
printf("getFilePathByLink() Failed!\n");
return(NULL);
}

char* last_slash = NULL;
//找到最后一个'/',last_slash保存其地址
last_slash = strrchr(pathbuf, '/');
//如果是空，则未找到'/'
if (last_slash == NULL) {
printf("can not find '/'!\n");
return(NULL);
}

int dir_len = 0;
char* dir = NULL;
dir_len = last_slash - pathbuf + 1; //包括末尾的'/'
dir = (char*) malloc(dir_len + 1);

strncpy(dir, pathbuf, dir_len);
dir[dir_len] = '\0';

return dir;
}

int main( int argc, char * argv[] )
{
char* myself_exec = NULL;
myself_exec = getFilePathByLink("/proc/self/exe");
if (NULL == myself_exec) {
printf("getFilePathByLink() Failed!\n");
} else {
printf("I'm the process, my executable file: %s\n", myself_exec);
}

char* myself_exec_dir = NULL;
myself_exec_dir = getFileDirByLink("/proc/self/exe");
printf("I'm the process, my executable file in: %s\n", myself_exec_dir);

free(myself_exec);
free(myself_exec_dir);
return(EXIT_SUCCESS);
}