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#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <strings.h>
#include <errno.h>
#define MEMINFO_FILE "/proc/meminfo"
#define MTAB_FILE "/etc/mtab"
#define BAD_OPEN_MESSAGE \
"Error: /proc must be mounted\n" \
" To mount /proc at boot you need an /etc/fstab line like:\n" \
" /proc /proc proc defaults\n" \
" In the meantime, run \"mount /proc /proc -t proc\"\n"
/* This macro opens filename only if necessary and seeks to 0 so
* that successive calls to the functions are more efficient.
* It also reads the current contents of the file into the global buf.
*/
#define FILE_TO_BUF(filename) do{ \
static int fd, local_n; \
if ((fd = open(filename, O_RDONLY)) == -1) { \
fputs(BAD_OPEN_MESSAGE, stderr); \
fflush(NULL); \
return -102; \
} \
lseek(fd, 0L, SEEK_SET); \
if ((local_n = read(fd, buf, sizeof buf - 1)) < 0) { \
perror(filename); \
fflush(NULL); \
return -103; \
} \
buf[local_n] = '\0'; \
close(fd); \
}while(0)
typedef struct mem_table_struct {
const char *name; /* memory type name */
unsigned long *slot; /* slot in return struct */
} mem_table_struct;
static int compare_mem_table_structs(const void *a, const void *b){
return strcmp(((const mem_table_struct*)a)->name,((const mem_table_struct*)b)->name);
}
size_t fastwriter_get_free_memory(void){
char buf[4096];
unsigned long kb_main_buffers, kb_main_cached, kb_main_free;
char namebuf[16]; /* big enough to hold any row name */
mem_table_struct findme = { namebuf, NULL};
mem_table_struct *found;
char *head;
char *tail;
const mem_table_struct mem_table[] = {
{"Buffers", &kb_main_buffers}, // important
{"Cached", &kb_main_cached}, // important
{"MemFree", &kb_main_free}, // important
};
const int mem_table_count = sizeof(mem_table)/sizeof(mem_table_struct);
FILE_TO_BUF(MEMINFO_FILE);
head = buf;
for(;;){
tail = strchr(head, ':');
if(!tail) break;
*tail = '\0';
if(strlen(head) >= sizeof(namebuf)){
head = tail+1;
goto nextline;
}
strcpy(namebuf,head);
found = bsearch(&findme, mem_table, mem_table_count,
sizeof(mem_table_struct), compare_mem_table_structs
);
head = tail+1;
if(!found) goto nextline;
*(found->slot) = strtoul(head,&tail,10);
nextline:
tail = strchr(head, '\n');
if(!tail) break;
head = tail+1;
}
return (kb_main_buffers + kb_main_cached + kb_main_free) * 1024;
}
int fastwriter_get_file_fs(const char *fname, size_t size, char *fs) {
int err = 0;
char buf[4096];
char *fn;
char *head;
char *tail;
size_t len, max = 0;
struct stat st;
if ((!fname)||(!fs)||(size < 3)) return EINVAL;
if (*fname == '/') {
fn = (char*)fname;
} else {
if (!getcwd(buf, 4095)) return errno;
fn = malloc(strlen(fname) + strlen(buf) + 2);
if (!fn) return ENOMEM;
sprintf(fn, "%s/%s", buf, fname);
}
if (!stat(fn, &st)) {
if (!S_ISREG(st.st_mode)) {
strcpy(fs, "raw");
goto clean;
}
}
FILE_TO_BUF(MTAB_FILE);
head = buf;
for(;;){
head = strchr(head, ' ');
if(!head) break;
head += 1;
tail = strchr(head, ' ');
if(!tail) break;
*tail = '\0';
len = strlen(head);
if((len <= max)||(strncmp(head, fn, len))) {
head = tail+1;
goto nextline;
}
head = tail + 1;
tail = strchr(head, ' ');
if(!tail) break;
*tail = '\0';
if (!strncasecmp(head,"root",4)) {
head = tail+1;
goto nextline;
}
max = len;
if (strlen(head) >= size) err = EFAULT;
else {
err = 0;
strcpy(fs, head);
}
head = tail+1;
nextline:
tail = strchr(head, '\n');
if(!tail) break;
head = tail+1;
}
clean:
if (fn != fname) free(fn);
return err;
}
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