Name
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| #include <accdb.h> struct accdb_module *accdb_load(char *module); void accdb_unload(struct accdb_module *mp); |
accdb_load() opens a back-end module (module.so and/or module.dll), acquires all necessary symbols and returns them in a malloc()ed struct accdb_module, which is then to be freed with accdb_unload(). In most cases, module will be just be an asterisk, which says to use the default ACCDB back-end, defined in etc/libaccdb/accdb, variable DEFAULT_BACKEND.
On failure, accdb_load() returns NULL and sets errno to the ones set by system calls, plus EFAULT if no q_open() function in the ACCDB module could be found. ENOENT is returned if no default module was defined.
| struct accdb_module *res = accdb_load("*"); |
The back-end interface is discussed in its own chapter.
Configuration file parsing 
While developing the Vitalnix Suite, I have come to a point where I realized I had common used code duplicated in nearly every file that used ACCDB in some way, so I decided to move that code part to ACCDB since it is a central place.
Configuration files are based on the key=value scheme, and lines beginning with a hash mark (#) are ignored, as are empty lines and unrecognized keys:
| # From etc/autouid # Minimum / maximum values for automatic UID selection UID_MIN=100 UID_MAX=65000 # Minimum / maximum values for automatic GID selection GID_MIN=100 GID_MAX=65000 |
ACCDB provides two (one) function to deal with configuration files:
| // From accdb.h struct rconfig_opt { const char *key; char type; void *ptr; int (*callback)(const char *, char, void *); }; enum { RCONFIG_ONE = 1 << 0, }; int accdb_rconfig(char *file, struct rconfig_opt *table); void accdb_rconfig_pv(const char **pv, char *file, struct rconfig_opt *table, unsigned long flags); |
Types for rconfig_opt.type can be 'b' (unsigned char / byte), 'c' (char), 'd' (double), 'f' (float), 'H'/'h' ([unsigned] short), 'I'/'i' ([unsigned] int), 'L'/'l' ([unsigned] long), 's' (char * / string). .callback is called when the corresponding option has been parsed and callback is not NULL. Since the options can be arranged in any order in the configuration file, you should take care when assuming that other keys/ptrs have already been filled.
To start parsing a file, call the accdb_rconfig() function with the corresponding parameters. If you want to read configuration files from different paths, i.e. to build up on default values, you can use accdb_rconfig_pv() like the next code example. (pv = path vector)
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struct rconfig_opt table[] = { {"UID_MIN", 'l', &uid_min, NULL}, {"UID_MAX", 'l', &uid_max, NULL}, {NULL}, }; const char *pv_a[] = {"/etc", "/usr/local/etc", NULL}, *pv_b[] = {".", "/etc", NULL}; // Will parse /etc/configfile accdb_rconfig("/etc/configfile", table); // Will parse /etc/configfile and /usr/local/etc/configfile accdb_rconfig_pv(pv_a, "configfile", table, 0); // Will only parse the first successful file accdb_rconfig_pv(pv_b, "configfile", table, RCONFIG_ONE); |
The call to accdb_rconfig() will either return 1 for success, 0 for no success (actually 0 is never returned) and -errno for an error. The next call, with pv_a will parse /etc/configfile, etc. (pv from left to right). No value is returned. The call with pv_b will only read the first successful opened file, i.e. if you have both ./configfile and /etc/configfile, only the former is read if it can be opened.
Password generation
| #include <accdb.h> int accdb_genpw(char *plain, char **crypted, size_t len, unsigned long meth, unsigned long flags); |
accdb_genpw() generates a random password. Depending on flags, it might even produce one to be easily memorized by humans, but still being pronouncible. The method and flags fields are:
| enum accdb_genpw_meth { PW_DES = 0, PW_MD5, PW_BLOWFISH, }; enum { PW_PHONEMIC = 1 << 0, PW_ONE_DIGIT = 1 << 1, PW_ONE_CASE = 1 << 2, }; |
November 29 2003