Maximum supported line length is BUFSIZ (8192)

[stoeckmann]

This is a follow-up of a discussion at Linux-PAM about differences in line parsers. Linux-PAM supports arbitrary line lengths now.

According to @thkukuk in comment linux-pam/linux-pam#741 (comment) this should be true for libeconf, too.

See this proof of concept that BUFSIZ has consequences on line parser:

1. Create a file with a line longer than BUFSIZ (8192)
   python -c 'print(8200*"a" + "=b")' > test.txt
2. Run following example program (shorter version of what pam_env.so does)

#include <libeconf.h>
#include <stdio.h>

int main(int argc, char *argv[])
{
        econf_file *key_file = NULL;
        econf_err error;
        char **keys = NULL;
        size_t key_number = 0;

        if (argc != 2) {
                fprintf(stderr, "supply file name to parse\n");
                return 1;
        }

        error = econf_readFile(&key_file, argv[1], "=", "#");
        if (error != ECONF_SUCCESS) {
                fprintf(stderr, "Unable to open file: %s: %s", argv[1],
                    econf_errString(error));
                return 2;
        }

        error = econf_getKeys(key_file, NULL, &key_number, &keys);
        if (error != ECONF_SUCCESS) {
                fprintf(stderr, "Unable to read keys: %s",
                    econf_errString(error));
                return 3;
        }

        for (size_t i = 0; i < key_number; i++) {
                char *val;

                error = econf_getStringValue(key_file, NULL, keys[i], &val);
                if (error != ECONF_SUCCESS) {
                        fprintf(stderr, "Unable tto get string from key %s: %s",
                            keys[i], econf_errString(error));
                        return 4;
                }
                printf("key: '%s', value: '%s'\n", keys[i], val);
        }

        return 0;
}

The output will be:

key: 'a....a', value: '(null)'
key: 'aaaaaaaaaa', value: 'b'

It shows that this one line is split into two. See https://github.com/openSUSE/libeconf/blob/master/lib/getfilecontents.c#L268 for relevant fgets usage.

I've seen this code part in the past, so I was fairly sure that this limitation still exists. And I think it should not be just replaced with getline without thinking about possible consequences of programs which use libeconf. Linux-PAM for example trusted in some parts of the code that parsed lines wouldn't be longer (imagine strcpy usages, for an over-simplified example).

[schubi2]

Fixed with #195 and version 0.6.1.
Thank you !

[schubi2]

closing....