probes.c

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/* -*- linux-c -*- */
/** @file probes.c
 * @brief Functions to assist loading and unloading groups of probes.
 */

/** Lookup name.
 * This simply calls the kernel function kallsyms_lookup_name().
 * That function is not exported, so this workaround is required.
 * See the kernel source, kernel/kallsyms.c for more information.
 */
static unsigned long (*_stp_lookup_name)(char *name)=(void *)KALLSYMS_LOOKUP_NAME;

/** Unregister a group of jprobes.
 * @param probes Pointer to an array of struct jprobe.
 * @param num_probes Number of probes in the array.
 */

void _stp_unregister_jprobes (struct jprobe *probes, int num_probes)
{
        int i;
        for (i = 0; i < num_probes; i++)
                unregister_jprobe(&probes[i]);
        dlog ("All jprobes removed\n");
}

/** Register a group of jprobes.
 * @param probes Pointer to an array of struct jprobe.
 * @param num_probes Number of probes in the array.
 * @return 0 on success.
 */

int _stp_register_jprobes (struct jprobe *probes, int num_probes)
{
        int i, ret ;
        unsigned long addr;

        for (i = 0; i < num_probes; i++) {
                addr =_stp_lookup_name((char *)probes[i].kp.addr);
                if (addr == 0) {
                        dlog ("ERROR: function %s not found!\n", 
                              (char *)probes[i].kp.addr);
                        ret = -1; /* FIXME */
                        goto out;
                }
                dlog("inserting jprobe at %s (%p)\n", probes[i].kp.addr, addr);
                probes[i].kp.addr = (kprobe_opcode_t *)addr;
                ret = register_jprobe(&probes[i]);
                if (ret)
                        goto out;
        }
        return 0;
out:
        dlog ("probe module initialization failed.  Exiting...\n");
        _stp_unregister_jprobes(probes, i);
        return ret;
}

/** Unregister a group of kprobes.
 * @param probes Pointer to an array of struct kprobe.
 * @param num_probes Number of probes in the array.
 */

void _stp_unregister_kprobes (struct kprobe *probes, int num_probes)
{
        int i;
        for (i = 0; i < num_probes; i++)
                unregister_kprobe(&probes[i]);
        dlog ("All kprobes removed\n");
}

/** Register a group of kprobes.
 * @param probes Pointer to an array of struct kprobe.
 * @param num_probes Number of probes in the array.
 * @return 0 on success.
 */

int _stp_register_kprobes (struct kprobe *probes, int num_probes)
{
        int i, ret ;
        unsigned long addr;

        for (i = 0; i < num_probes; i++) {
                addr =_stp_lookup_name((char *)probes[i].addr);
                if (addr == 0) {
                        dlog ("ERROR: function %s not found!\n", 
                              (char *)probes[i].addr);
                        ret = -1; /* FIXME */
                        goto out;
                }
                dlog("inserting kprobe at %s (%p)\n", probes[i].addr, addr);
                probes[i].addr = (kprobe_opcode_t *)addr;
                ret = register_kprobe(&probes[i]);
                if (ret)
                        goto out;
        }
        return 0;
out:
        dlog ("probe module initialization failed.  Exiting...\n");
        _stp_unregister_kprobes(probes, i);
        return ret;
}