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Vitalnix | : User Management Suite |
| manual | v1.90.8.3 |
libaccdb - The Unified Account Database
libaccdb provides some essential functions for applications wishing to access a user database. It also contains some common used code, such as password generation routines. Applications that wish to use ACCDB must link against it, usually with gcc's -laccdb parameter.
| #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.
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; }; enum accdb_rconfig_flags { 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, enum accdb_rconfig_flags fl); |
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}, {"UID_MAX", 'l', &uid_max}, {NULL, '\0', 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.
| #include <accdb.h> int accdb_genpw(char *plain, char **crypted, size_t len, enum accdb_genpw_meth meth, enum accdb_genpw_flags flags, void *randp); |
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 accdb_genpw_flags { PW_PHONEMIC = 1 << 0, PW_ONE_DIGIT = 1 << 1, PW_ONE_CASE = 1 << 2, }; |
November 14 2003