Question

I’ve got an library which must read data from sqlite database by calling

extern int read(char** argv, int argc); // from header

it must process:

int read(char** argv, int argc) {
    char* lineborder1;
    char* lineborder2;
    char* spaces1;
    char* spaces2;
    int maxl2 = 0, maxl1 = 0;
    int i, maxi1, maxi2;
    if (prelude() == -1) return -1;
    // etc...

where prelude is inner procedure for sqlite connection:

int prelude() {
    timefile = 0;
    f = NULL;
#ifndef WIN32
    char* temp = (char*)calloc(200, sizeof(char));
#endif
    queries = (char**)malloc(sizeof(char*) * q_cnt);
    for (x = 0; x < q_cnt; x++) {
        queries[x] = (char*)malloc(sizeof(char) * q_size);
        }
#ifdef WIN32
    retval = sqlite3_open("todo.db3", &handle);
#else
    home = (char*)getenv("HOME");
    strcpy(temp, home);
    retval = sqlite3_open(strcat(temp, "/.todo.db3"), &handle);
    free(temp);
#endif
    if (retval) {
        printf("Database connection failed\n\r");
        return -1;
        }
    return 0;
    }

whole source is here : bitbucket: ctodo.c

I call this read from my application:

else if ((strcmp(argv[1], "read") == 0) || (strcmp(argv[1], "r") == 0)) {
    return read(argv, argc);

but getting infinity cycle of this read call:

>>./todo r
Database connection failed
Database connection failed
Database connection failed
.... etc

here is how do I build it:

gcc -I . -c -o todo.a ctodo.c -lsqlite3 -O3
gcc -I . -o todo cctodo.c -lsqlite3 -O3 todo.a

help or version calls wrok fine and read works fine on windows, something specific to my linux build is here but I can’t find a bug so far. what could call this read to run in infinity cycle like that?

Answer 1

The read function is defined in libc.so, and used to, you know, read data.

It is exceedingly likely that sqlite3_open() calls it.

By introducing your own function called read(), you’ve made your program enter infinite loop. If you wait long enough, your program will run out of stack and crash.

Doctor, it hurts when I do that. Well, don’t do that 🙂