fix: 实现了musl库net模块中的一些函数接口

【背景】
musl库net模块的有一些API没有实现

【修改方案】
实现了musl库net模块中的一些API
删去了已经实现的API中unsupported api的标识

【影响】
对现有的产品编译不会有影响。

re #I4JQI1
Signed-off-by: Nyinjiaming <yinjiaming@huawei.com>
Change-Id: I83ad41c9ab565bf5838158b39961210a67bdad40

porting/liteos_a/user/src/network/ent.c

-#include <netdb.h>
-#include <unsupported_api.h>
+#define _BSD_SOURCE
+#include<netdb.h>
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+#include<arpa/inet.h>
+#include<errno.h>
 
-void sethostent(int x)
+#define HOST_FILE_PATH "/etc/hosts"
+#define NET_FILE_PATH  "/etc/networks"
+#define BUFFER_SIZE    200
+#define INET_ADDR_LEN  4
+#define INET6_ADDR_LEN 16
+#define MAX_ALIAS_NO   10
+#define MAX_ADDR_NO    10
+#define MAX_NAME_LEN   20
+#define MAX_ALIAS_LEN  20
+
+struct hostdata {
+	FILE *hostf;
+	int stayopen;
+	struct hostent he;
+	char buf[BUFFER_SIZE];
+	char *addr[MAX_ADDR_NO + 1];
+	char addr_list[MAX_ADDR_NO + 1][INET6_ADDR_LEN + 1];
+	char *aliases[MAX_ALIAS_NO + 1];
+};
+
+struct netdata {
+	FILE *netf;
+	int stayopen;
+	struct netent ne;
+	char buf[BUFFER_SIZE];
+	char *aliases[MAX_ALIAS_NO + 1];
+};
+
+static struct hostdata *hd = NULL;
+static struct netdata  *nd = NULL;
+
+static int gethostent_resolv()
 {
-	unsupported_api(__FUNCTION__);
+	char *ch, *ptr = NULL;
+	if (hd->buf[0] == '#')
+		return -1;
+
+	ch = strchr(hd->buf, '#');
+	if (ch) 
+		*ch = '\0';
+	ch = strtok_r(hd->buf, " \t\n", &ptr);
+	if (!ch)
+		return -1;
+
+	if (inet_pton(AF_INET, ch, hd->addr_list[0]) == 1) {
+		hd->he.h_addrtype = AF_INET;
+		hd->he.h_length = INET_ADDR_LEN;
+		hd->addr_list[0][INET_ADDR_LEN] = '\0';
+	} else if (inet_pton(AF_INET6, ch, hd->addr_list[0]) == 1) {
+		hd->he.h_addrtype = AF_INET6;
+		hd->he.h_length = INET6_ADDR_LEN;
+		hd->addr_list[0][INET6_ADDR_LEN] = '\0';
+	} else {
+		return -1;
+	}
+
+	hd->addr[0] = hd->addr_list[0];
+	hd->addr[1] = NULL;
+	hd->he.h_addr_list = hd->addr;
+
+	ch = strtok_r(NULL, " \t\n", &ptr);
+	if (!ch)
+		return -1;
+	hd->he.h_name = ch;
+
+	int i = 0;
+	while (i < MAX_ALIAS_NO) {
+		ch = strtok_r(NULL, " \t\n", &ptr);
+		hd->aliases[i++] = ch;
+	}
+
+	hd->aliases[MAX_ALIAS_NO] = NULL;
+	hd->he.h_aliases = hd->aliases;
+	return 0;
 }
 
-struct hostent *gethostent()
+struct hostent *gethostent(void)
 {
-	unsupported_api(__FUNCTION__);
-	return 0;
+	if (hd == NULL) {
+		if ((hd = malloc(sizeof(struct hostdata))) == NULL) {
+			h_errno = NO_RECOVERY;
+			return NULL;
+		}
+		hd->hostf = NULL;
+		hd->stayopen = 0;
+	}
+	if (!hd->hostf && !(hd->hostf = fopen(HOST_FILE_PATH, "r"))) {
+		h_errno = NO_RECOVERY;
+		free(hd);
+		hd =NULL;
+		return NULL;
+	}
+	do {
+		if (!fgets(hd->buf, BUFFER_SIZE, hd->hostf)) {
+			h_errno = HOST_NOT_FOUND;
+			return NULL;
+		}
+	} while (gethostent_resolv());
+
+	return &(hd->he);
 }
 
-struct netent *getnetent()
+void sethostent(int stayopen)
 {
-	unsupported_api(__FUNCTION__);
-	return 0;
+	if (hd == NULL) {
+		if ((hd = malloc(sizeof(struct hostdata))) == NULL) {
+			h_errno = NO_RECOVERY;
+			return;
+		}
+		hd->hostf = NULL;
+	}
+	if (hd->hostf == NULL)
+		hd->hostf = fopen(NET_FILE_PATH, "r");
+	else
+		rewind(hd->hostf);
+	hd->stayopen = stayopen;
 }
 
 void endhostent(void)
 {
-	unsupported_api(__FUNCTION__);
+	if (hd == NULL)
+		return;
+	if (hd->stayopen == 0) {
+		if (hd->hostf != NULL)
+			fclose(hd->hostf);
+		free(hd);
+		hd = NULL;
+	}
 }
 
-weak_alias(sethostent, setnetent);
-weak_alias(endhostent, endnetent);
+static int getnetent_resolv()
+{
+	if (nd->buf[0] == '#')
+		return -1;
+	char *ch, *ptr = NULL;
+	ch = strchr(nd->buf, '#');
+	if (ch) 
+		*ch = '\0';
+	ch = strtok_r(nd->buf, " \t\n", &ptr);
+	if (!ch)
+		return -1;
+	nd->ne.n_name = ch;
+	nd->ne.n_addrtype = AF_INET;
+
+	ch = strtok_r(NULL, " \t\n", &ptr);
+	if (!ch) 
+		return -1;
+	nd->ne.n_net = inet_network(ch);	
+
+	int i = 0;
+	while ((ch = strtok_r(NULL, " \t\n", &ptr)) != NULL && i < MAX_ALIAS_NO) {
+		nd->aliases[i++] = ch;
+	}
+	nd->aliases[i] = NULL;	
+	nd->ne.n_aliases = nd->aliases;
+	return 0;
+}
+
+struct netent *getnetent(void)
+{
+	if (nd == NULL) {
+		if ((nd = malloc(sizeof(struct netdata))) == NULL) {
+			errno = ENOMEM;
+			return NULL;
+		}
+		nd->netf = NULL;
+		nd->stayopen = 0;
+	}
+	if (nd->netf == NULL && (nd->netf = fopen(NET_FILE_PATH, "r")) == NULL) {
+		errno = ENOENT;
+		free(nd);
+		nd = NULL;
+		return NULL;
+	}
+	while (1) { 
+		if (fgets(nd->buf, BUFFER_SIZE, nd->netf) == NULL)
+			break;
+		if (getnetent_resolv() == 0)
+			return &(nd->ne);
+	}
+
+	return NULL;
+}
+
+void setnetent(int stayopen)
+{
+	if (nd == NULL) {
+		if ((nd = malloc(sizeof(struct netdata))) == NULL) {
+			errno = ENOMEM;
+			return;
+		}
+		nd->netf = NULL;
+	}
+	if (nd->netf == NULL)
+		nd->netf = fopen(NET_FILE_PATH, "r");
+	else
+		rewind(nd->netf);
+	nd->stayopen = stayopen;
+}
+
+void endnetent(void)
+{
+	if (nd == NULL)
+		return;
+	if (!nd->stayopen) {
+		if (nd->netf != NULL)
+			fclose(nd->netf);
+		free(nd);
+		nd = NULL;
+	}
+}
\ No newline at end of file

porting/liteos_a/user/src/network/ether.c

 #include <stdlib.h>
 #include <netinet/ether.h>
 #include <stdio.h>
-#include <unsupported_api.h>
+#include <string.h>
+#include <errno.h>
+
+#define ETHER_FILE_PATH "/etc/ethers"
+#define BUFFER_SIZE     200
 
 struct ether_addr *ether_aton_r (const char *x, struct ether_addr *p_a)
 {
@@ -43,20 +47,97 @@ char *ether_ntoa (const struct ether_addr *p_a) {
 	return ether_ntoa_r (p_a, x);
 }
 
-int ether_line(const char *l, struct ether_addr *e, char *hostname)
+int ether_line(const char *line, struct ether_addr *addr, char *hostname)
 {
-	unsupported_api(__FUNCTION__);
-	return -1;
+	char buf[BUFFER_SIZE], *ch, *ptr = NULL;
+	if (line[0] == '#') {
+		errno = EINVAL;
+		return -1;
+	}
+	strcpy(buf, line);
+	ch = strchr(buf, '#');
+	if (ch)
+		*ch = '\0';
+	ch = strtok_r(buf, " \t\n", &ptr);
+	ch = strtok_r(NULL, " \t\n", &ptr);
+	if (ch == NULL) {
+		errno = EINVAL;
+		return -1;
+	}
+	strcpy(hostname, ch);
+
+	unsigned int ret;
+	ch = &buf[0];
+	for (int i = 0; i < 6; i++) {
+		ch = strtok_r(ch, ":", &ptr);
+		if (ch == NULL || sscanf(ch, "%x", &ret) != 1) {
+			errno = EINVAL;
+			return -1;
+		}
+		addr->ether_addr_octet[i] = (uint8_t)ret;
+		ch = NULL;
+	}
+
+	return 0;     
 }
 
-int ether_ntohost(char *hostname, const struct ether_addr *e)
-{
-	unsupported_api(__FUNCTION__);
+int ether_ntohost(char *hostname, const struct ether_addr *addr)
+{   
+	FILE *f = NULL;
+	char buf[BUFFER_SIZE + 1];
+	char temp_name[BUFFER_SIZE];
+	struct ether_addr *temp_addr;
+    
+	if (!(f = fopen(ETHER_FILE_PATH, "r")))
+		return ENOENT;
+	temp_addr = (struct ether_addr *)malloc(sizeof(struct ether_addr));
+	if (temp_addr == NULL) {
+		fclose(f);
+		return ENOMEM;
+	}
+	while (fgets(buf, BUFFER_SIZE, f)) {
+		if (ether_line(buf, temp_addr, temp_name) != 0)
+			continue;
+		if (memcmp(addr, temp_addr, 6) == 0) {
+			strcpy(hostname, temp_name);
+			free(temp_addr);
+			fclose(f);
+			return 0; 
+		}
+	}
+
+	free(temp_addr);
+	fclose(f);
 	return -1;
 }
 
-int ether_hostton(const char *hostname, struct ether_addr *e)
+
+int ether_hostton(const char *hostname, struct ether_addr *addr)
 {
-	unsupported_api(__FUNCTION__);
+	FILE *f = NULL;
+	char buf[BUFFER_SIZE + 1];
+	char temp_name[BUFFER_SIZE];
+	struct ether_addr *temp_addr;
+	
+	temp_addr = (struct ether_addr *)malloc(sizeof(struct ether_addr));
+	if (temp_addr == NULL)
+		return ENOMEM;
+	if (!(f = fopen(ETHER_FILE_PATH, "r"))) {
+		free(temp_addr);
+		return ENOENT;
+	}
+	while (fgets(buf, BUFFER_SIZE, f)) {
+		if (ether_line(buf, temp_addr, temp_name) != 0)
+			continue;
+		if (strcmp(hostname, temp_name) == 0) {
+			memcpy(addr, temp_addr, 6);
+			free(temp_addr);
+			fclose(f);
+			return 0; 
+		}
+	}
+    
+	free(temp_addr);
+	fclose(f);
 	return -1;
 }

porting/liteos_a/user/src/network/gethostbyaddr.c

@@ -3,7 +3,6 @@
 #include <netdb.h>
 #include <errno.h>
 #include <stdlib.h>
-#include <unsupported_api.h>
 
 struct hostent *gethostbyaddr(const void *a, socklen_t l, int af)
 {
@@ -11,7 +10,6 @@ struct hostent *gethostbyaddr(const void *a, socklen_t l, int af)
 	size_t size = 63;
 	struct hostent *res;
 	int err;
-	unsupported_api(__FUNCTION__);
 	do {
 		free(h);
 		h = malloc(size+=size+1);

porting/liteos_a/user/src/network/gethostbyaddr_r.c

@@ -6,7 +6,6 @@
 #include <netinet/in.h>
 #include <errno.h>
 #include <inttypes.h>
-#include <unsupported_api.h>
 
 int gethostbyaddr_r(const void *a, socklen_t l, int af,
 	struct hostent *h, char *buf, size_t buflen,
@@ -20,7 +19,6 @@ int gethostbyaddr_r(const void *a, socklen_t l, int af,
 	int i;
 
 	*res = 0;
-	unsupported_api(__FUNCTION__);
 	/* Load address argument into sockaddr structure */
 	if (af==AF_INET6 && l==16) memcpy(&sa.sin6.sin6_addr, a, 16);
 	else if (af==AF_INET && l==4) memcpy(&sa.sin.sin_addr, a, 4);

porting/liteos_a/user/src/network/gethostbyname_r.c

@@ -2,12 +2,10 @@
 
 #include <sys/socket.h>
 #include <netdb.h>
-#include <unsupported_api.h>
 
 int gethostbyname_r(const char *name,
 	struct hostent *h, char *buf, size_t buflen,
 	struct hostent **res, int *err)
 {
-	unsupported_api(__FUNCTION__);
 	return gethostbyname2_r(name, AF_INET, h, buf, buflen, res, err);
 }

porting/liteos_a/user/src/network/getifaddrs.c

@@ -7,10 +7,12 @@
 #include <syscall.h>
 #include <net/if.h>
 #include <netinet/in.h>
-#include <unsupported_api.h>
+#include <sys/ioctl.h>
 #include "netlink.h"
+#include<stdio.h>
 
 #define IFADDRS_HASH_SIZE 64
+#define MAX_IF_NO 10
 
 /* getifaddrs() reports hardware addresses with PF_PACKET that implies
  * struct sockaddr_ll.  But e.g. Infiniband socket address length is
@@ -47,11 +49,17 @@ struct ifaddrs_ctx {
 
 void freeifaddrs(struct ifaddrs *ifp)
 {
-	struct ifaddrs *n;
+	struct ifaddrs *tmp = NULL;
 	while (ifp) {
-		n = ifp->ifa_next;
+		if (!ifp->ifa_name)
+			free(ifp);
+		if (!ifp->ifa_addr)
+			free(ifp->ifa_addr);
+		if (!ifp->ifa_netmask)
+			free(ifp->ifa_netmask);
+		tmp = ifp->ifa_next;
 		free(ifp);
-		ifp = n;
+		ifp = tmp;
 	}
 }
 
@@ -205,14 +213,85 @@ static int netlink_msg_to_ifaddr(void *pctx, struct nlmsghdr *h)
 	return 0;
 }
 
+
+static struct ifaddrs* ifaddrs_init()
+{
+	struct ifaddrs *ifa = NULL;
+	ifa = malloc(sizeof(struct ifaddrs));
+	if (!ifa)
+		return NULL;
+	ifa->ifa_name = malloc(sizeof(char) *(IF_NAMESIZE + 1));
+	ifa->ifa_addr = malloc(sizeof(struct sockaddr));
+	ifa->ifa_netmask = malloc(sizeof(struct sockaddr));
+	ifa->ifa_next = NULL;
+	if (!ifa->ifa_name || !ifa->ifa_addr || !ifa->ifa_netmask) {
+		free(ifa->ifa_name);
+		free(ifa->ifa_addr);
+		free(ifa->ifa_netmask);
+		free(ifa);
+		return NULL;
+	}
+	return ifa;
+}
+
 int getifaddrs(struct ifaddrs **ifap)
 {
-	struct ifaddrs_ctx _ctx, *ctx = &_ctx;
-	int r;
-	unsupported_api(__FUNCTION__);
-	memset(ctx, 0, sizeof *ctx);
-	r = __rtnetlink_enumerate(AF_UNSPEC, AF_UNSPEC, netlink_msg_to_ifaddr, ctx);
-	if (r == 0) *ifap = &ctx->first->ifa;
-	else freeifaddrs(&ctx->first->ifa);
-	return r;
+	if (ifap == NULL) {
+		errno = EINVAL;
+		return -1;
+	}
+	
+	int fd, ifno, ret;
+	struct ifreq ifr[MAX_IF_NO];
+	struct ifconf ifconfig;
+	struct ifaddrs *ifstart = NULL;
+
+	ifconfig.ifc_buf = ifr;
+	ifconfig.ifc_len = sizeof(ifr);
+	if ((fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0)) < 0) 
+		return -1;
+	if (ioctl(fd, SIOCGIFCONF, &ifconfig) < 0)
+		goto error;
+	if (ifconfig.ifc_len % sizeof(struct ifreq)) {
+		errno = EINVAL;
+		goto error;
+	}
+	ifno = ifconfig.ifc_len / sizeof(struct ifreq);
+
+	if (!(ifstart = ifaddrs_init())) {
+		errno = ENOMEM;
+		goto error;
+	}
+	struct ifaddrs *ifa = ifstart;
+
+	for (int i = 0; i < ifno; i++) {
+		memcpy(ifa->ifa_name, ifr[i].ifr_name, IF_NAMESIZE);
+		ifa->ifa_name[IF_NAMESIZE] = '\0';
+		memcpy(ifa->ifa_addr, &ifr[i].ifr_addr, sizeof(struct sockaddr));
+		if (ioctl(fd, SIOCGIFNETMASK, &ifr[i]) < 0)
+			goto error;
+		memcpy(ifa->ifa_netmask, &ifr[i].ifr_netmask, sizeof(struct sockaddr));
+
+		if (ioctl(fd, SIOCGIFFLAGS, &ifr[i]) < 0) 
+			goto error;
+		ifa->ifa_flags = ifr[i].ifr_flags;
+
+		if (i < ifno - 1) {
+			ifa->ifa_next = ifaddrs_init();
+			if (!ifa->ifa_next)	{
+				errno = ENOMEM;
+				goto error;
+			}
+			ifa = ifa->ifa_next;
+		}
+	}
+
+	*ifap = ifstart;
+	return 0;
+
+error:	
+	freeifaddrs(ifstart);
+	__syscall(SYS_close, fd);
+	return -1;
 }
+

porting/liteos_a/user/src/network/getnameinfo.c

@@ -9,7 +9,6 @@
 #include <net/if.h>
 #include <ctype.h>
 #include <resolv.h>
-#include <unsupported_api.h>
 #include "lookup.h"
 #include "stdio_impl.h"
 
@@ -130,7 +129,6 @@ int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
 	unsigned char *a;
 	unsigned scopeid;
 
-	unsupported_api(__FUNCTION__);
 	switch (af) {
 	case AF_INET:
 		a = (void *)&((struct sockaddr_in *)sa)->sin_addr;

porting/liteos_a/user/src/network/getservbyname.c

 #define _GNU_SOURCE
 #include <netdb.h>
-#include <unsupported_api.h>
 
 struct servent *getservbyname(const char *name, const char *prots)
 {
 	static struct servent se;
 	static char *buf[2];
 	struct servent *res;
-	unsupported_api(__FUNCTION__);
 	if (getservbyname_r(name, prots, &se, (void *)buf, sizeof buf, &res))
 		return 0;
 	return &se;

porting/liteos_a/user/src/network/getservbyname_r.c

@@ -7,7 +7,6 @@
 #include <string.h>
 #include <stdlib.h>
 #include "lookup.h"
-#include <unsupported_api.h>
 
 #define ALIGN (sizeof(struct { char a; char *b; }) - sizeof(char *))
 
@@ -18,7 +17,6 @@ int getservbyname_r(const char *name, const char *prots,
 	int cnt, proto, align;
 
 	*res = 0;
-	unsupported_api(__FUNCTION__);
 
 	/* Don't treat numeric port number strings as service records. */
 	char *end = "";

porting/liteos_a/user/src/network/getservbyport.c

 #define _GNU_SOURCE
 #include <netdb.h>
-#include <unsupported_api.h>
 
 struct servent *getservbyport(int port, const char *prots)
 {
 	static struct servent se;
 	static long buf[32/sizeof(long)];
 	struct servent *res;
-	unsupported_api(__FUNCTION__);
 	if (getservbyport_r(port, prots, &se, (void *)buf, sizeof buf, &res))
 		return 0;
 	return &se;

porting/liteos_a/user/src/network/getservbyport_r.c

@@ -6,7 +6,6 @@
 #include <errno.h>
 #include <string.h>
 #include <stdlib.h>
-#include <unsupported_api.h>
 
 int getservbyport_r(int port, const char *prots,
 	struct servent *se, char *buf, size_t buflen, struct servent **res)
@@ -16,7 +15,6 @@ int getservbyport_r(int port, const char *prots,
 		.sin_family = AF_INET,
 		.sin_port = port,
 	};
-	unsupported_api(__FUNCTION__);
 
 	if (!prots) {
 		int r = getservbyport_r(port, "tcp", se, buf, buflen, res);
@@ -53,7 +51,6 @@ int getservbyport_r(int port, const char *prots,
 	case 0:
 		break;
 	}
-
 	/* A numeric port string is not a service record. */
 	if (strtol(buf, 0, 10)==ntohs(port)) return ENOENT;
 

porting/liteos_a/user/src/network/if_indextoname.c

@@ -4,15 +4,13 @@
 #include <sys/ioctl.h>
 #include <string.h>
 #include <errno.h>
-#include <unsupported_api.h>
 #include "syscall.h"
 
 char *if_indextoname(unsigned index, char *name)
 {
 	struct ifreq ifr;
 	int fd, r;
-	unsupported_api(__FUNCTION__);
-	if ((fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) return 0;
+	if ((fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) return 0;
 	ifr.ifr_ifindex = index;
 	r = ioctl(fd, SIOCGIFNAME, &ifr);
 	__syscall(SYS_close, fd);

porting/liteos_a/user/src/network/if_nametoindex.c

@@ -3,15 +3,14 @@
 #include <sys/socket.h>
 #include <sys/ioctl.h>
 #include <string.h>
-#include <unsupported_api.h>
 #include "syscall.h"
 
 unsigned if_nametoindex(const char *name)
 {
 	struct ifreq ifr;
 	int fd, r;
-	unsupported_api(__FUNCTION__);
-	if ((fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) return 0;
+	
+	if ((fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) return 0;
 	strncpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
 	r = ioctl(fd, SIOCGIFINDEX, &ifr);
 	__syscall(SYS_close, fd);

porting/liteos_a/user/src/network/netname.c

 #include <netdb.h>
-#include <unsupported_api.h>
+#include <string.h>
 
-struct netent *getnetbyaddr(uint32_t net, int type)
-{
-	unsupported_api(__FUNCTION__);
-	return 0;
+struct netent *getnetbyaddr(uint32_t net, int addrtype)
+{	
+	struct netent *ne = NULL;
+	setnetent(1);
+	while (1) {
+		ne = getnetent();
+		if (!ne)
+			break;
+		if (ne->n_net == net && ne->n_addrtype == addrtype) {
+			setnetent(0);
+			endnetent();
+			return ne;
+		}
+	}
+	setnetent(0);
+	endnetent();
+	return NULL;
 }
 
-struct netent *getnetbyname(const char *name)
+struct netent *getnetbyname(const char *netname)
 {
-	unsupported_api(__FUNCTION__);
-	return 0;
+	struct netent *ne = NULL;
+	setnetent(1);
+	while (1) {
+		ne = getnetent();
+		if (!ne)
+			break;
+		if (strcmp(ne->n_name, netname) == 0) {
+			setnetent(0);
+			endnetent();
+			return ne;
+		}
+	}
+	setnetent(0);
+	endnetent();
+	return NULL;
 }
 

porting/liteos_a/user/src/network/proto.c

 #include <netdb.h>
 #include <string.h>
-#include <unsupported_api.h>
 
 /* do we really need all these?? */
 
@@ -46,7 +45,6 @@ static const unsigned char protos[] = {
 
 void endprotoent(void)
 {
-	unsupported_api(__FUNCTION__);
 	idx = 0;
 }
 

porting/liteos_a/user/src/network/serv.c

-#include <netdb.h>
-#include <unsupported_api.h>
+#define _BSD_SOURCE
+#include<netdb.h>
+#include<errno.h>
+#include<stdlib.h>
+#include<stdio.h>
+#include<string.h>
 
-void endservent(void)
+#define SERV_FILE_PATH  "/etc/services"
+#define BUFFER_SIZE     200
+#define MAX_PORT        65535
+#define MAX_ALIAS_NO    10
+
+struct servdata
 {
-	unsupported_api(__FUNCTION__);
-}
+	FILE *servf;
+	int stayopen;
+	struct servent se;
+	char buf[BUFFER_SIZE];
+	char *alias_list[MAX_ALIAS_NO + 1];
+};
+static struct servdata *sd = NULL;
 
-void setservent(int stayopen)
+static int servent_resolv()
 {
-	unsupported_api(__FUNCTION__);
+	if (sd->buf[0] == '#')
+		return -1;
+	char *ch, *temp, *ptr = NULL;
+	ch = strchr(sd->buf, '#');
+	if (ch)
+		*ch = '\0';
+	ch = strtok_r(sd->buf, " \t\n", &ptr);
+	temp = strtok_r(NULL, " \t\n", &ptr);
+	if (!ch || !temp)
+		return -1;
+		
+	sd->se.s_name = ch;
+	ch = strchr(temp, '/');
+	if (ch == NULL)
+		return -1;
+	*ch++ = '\0'; 
+	sd->se.s_port = atoi(temp);
+	if (sd->se.s_port < 1 || sd->se.s_port > MAX_PORT)
+		return -1;
+	sd->se.s_port = htons(sd->se.s_port);
+	if (strcmp(ch, "tcp") != 0 && strcmp(ch, "udp") != 0)
+		return -1;
+	sd->se.s_proto = ch;
+
+	int i = 0;
+	while (i < MAX_ALIAS_NO) {
+		ch = strtok_r(NULL, " \t\n", &ptr);
+		sd->alias_list[i++] = ch;
+	}
+	sd->alias_list[MAX_ALIAS_NO] = NULL;
+	sd->se.s_aliases = sd->alias_list;
+	return 0;
 }
 
 struct servent *getservent(void)
 {
-	unsupported_api(__FUNCTION__);
-	return 0;
+	if (sd == NULL) {
+		if ((sd = malloc(sizeof(struct servdata))) == NULL) {
+			errno = ENOMEM;
+			return NULL;
+		}
+		sd->servf = NULL;
+		sd->stayopen = 0;
+	}
+	if (!sd->servf && !(sd->servf = fopen(SERV_FILE_PATH, "r"))) {
+		errno = ENOENT;
+		free(sd);
+		sd = NULL;
+		return NULL;
+	}
+	do {
+		if (!fgets(sd->buf, BUFFER_SIZE - 1, sd->servf)) {
+			errno = EINVAL;
+			return NULL;
+		}
+	} while (servent_resolv());
+	return &(sd->se);
 }
+
+void endservent(void)
+{
+	if (sd == NULL)
+		return;
+	if (sd->stayopen == 0) {
+		if (sd->servf != NULL)
+			fclose(sd->servf);
+		free(sd);
+		sd = NULL;
+	}
+}
+
+void setservent(int stayopen)
+{
+	if (sd == NULL) {
+		if ((sd = malloc(sizeof(struct servdata))) == NULL) {
+			errno = ENOMEM;
+			return;
+		}
+		sd->servf = NULL;
+	}
+	if (!sd->servf)
+		sd->servf = fopen(SERV_FILE_PATH, "r");
+	else
+		rewind(sd->servf);
+	sd->stayopen = stayopen;    
+}
\ No newline at end of file