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di_init(3devinfo) [centos man page]

di_init(3DEVINFO)														 di_init(3DEVINFO)

di_init, di_fini - create and destroy a snapshot of kernel device tree SYNOPSIS
cc [ flag... ] file... -ldevinfo [ library... ] #include <libdevinfo.h> di_node_t di_init(const char *phys_path, uint_t flags); void di_fini(di_node_t root); flags Snapshot content specification. The possible values can be a bitwise OR of the following: DINFOSUBTREE Include subtree. DINFOPROP Include properties. DINFOMINOR Include minor data. DINFOCPYALL Include all of the above. DINFOLYR Include device layering data. If flags is 0, the snapshot contains only a single node without properties or minor nodes. phys_path Physical path of the root node of the snapshot. See di_devfs_path(3DEVINFO). root Handle obtained by calling di_init(). The di_init() function creates a snapshot of the kernel device tree and returns a handle of the root node. The caller specifies the con- tents of the snapshot by providing flag and phys_path. The di_fini() function destroys the snapshot of the kernel device tree and frees the associated memory. All handles associated with this snapshot become invalid after the call to di_fini(). Upon success, di_init() returns a handle. Otherwise, DI_NODE_NIL is returned and errno is set to indicate the error. The di_init() function can set errno to any error code that can also be set by open(2), ioctl(2) or mmap(2). The most common error codes include: EACCES Insufficient privilege for accessing device configuration data. ENXIO Either the device named by phys_path is not present in the system, or the devinfo(7D) driver is not installed properly. EINVAL Either phys_path is incorrectly formed or the flags argument is invalid. Example 1: Using the libdevinfo Interfaces To Print All Device Tree Node Names The following is an example using the libdevinfo interfaces to print all device tree node names: /* * Code to print all device tree node names */ #include <stdio.h> #include <libdevinfo.h> int prt_nodename(di_node_t node, void *arg) { printf("%s ", di_node_name(node)); return (DI_WALK_CONTINUE); } main() { di_node_t root_node; if((root_node = di_init("/", DINFOSUBTREE)) == DI_NODE_NIL) { fprintf(stderr, "di_init() failed "); exit(1); } di_walk_node(root_node, DI_WALK_CLDFIRST, NULL, prt_nodename); di_fini(root_node); } Example 2: Using the libdevinfo Interfaces To Print The Physical Path Of SCSI Disks The following example uses the libdevinfo interfaces to print the physical path of SCSI disks: /* * Code to print physical path of scsi disks */ #include <stdio.h> #include <libdevinfo.h> #define DISK_DRIVER "sd" /* driver name */ void prt_diskinfo(di_node_t node) { int instance; char *phys_path; /* * If the device node exports no minor nodes, * there is no physical disk. */ if (di_minor_next(node, DI_MINOR_NIL) == DI_MINOR_NIL) { return; } instance = di_instance(node); phys_path = di_devfs_path(node); printf("%s%d: %s ", DISK_DRIVER, instance, phys_path); di_devfs_path_free(phys_path); } void walk_disknodes(di_node_t node) { node = di_drv_first_node(DISK_DRIVER, node); while (node != DI_NODE_NIL) { prt_diskinfo(node); node = di_drv_next_node(node); } } main() { di_node_t root_node; if ((root_node = di_init("/", DINFOCPYALL)) == DI_NODE_NIL) { fprintf(stderr, "di_init() failed "); exit(1); } walk_disknodes(root_node); di_fini(root_node); } See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Evolving | +-----------------------------+-----------------------------+ |MT-Level |Safe | +-----------------------------+-----------------------------+ open(2), ioctl(2), mmap(2), libdevinfo(3LIB), attributes(5) 8 Dec 2003 di_init(3DEVINFO)

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