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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>
- #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); \
- _exit(102); \
- } \
- lseek(fd, 0L, SEEK_SET); \
- if ((local_n = read(fd, buf, sizeof buf - 1)) < 0) { \
- perror(filename); \
- fflush(NULL); \
- _exit(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 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 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 -1;
-
- if (*fname == '/') {
- fn = (char*)fname;
- } else {
- if (!getcwd(buf, 4095)) return -1;
- fn = malloc(strlen(fname) + strlen(buf) + 2);
- if (!fn) return -1;
- sprintf(fn, "%s/%s", buf, fname);
- }
-
- if (!stat(fn, &st)) {
- if (S_ISBLK(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 = -1;
- 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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