loop: refactor: extract subfunction set_loopdev_params()

Extract subfunction set_loop_info() from set_loop() function old new delta set_loop 760 784 +24 Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
author: Xiaoming Ni <nixiaoming@huawei.com> 2022-12-13 13:13:23 +0100
committer: Denys Vlasenko <vda.linux@googlemail.com> 2022-12-13 14:26:20 +0100
commit: a1856934ba795f81546f5dd9a14ba4faa757ce52 (patch)
tree: 8d81c51e88ba4390440be5a63d29524be1dc4765 /libbb
parent: 7dc76c9f210b3c66a9c89e6690af7b49f6c540a8 (diff)
download: busybox-w32-a1856934ba795f81546f5dd9a14ba4faa757ce52.tar.gz
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1 files changed, 51 insertions, 39 deletions
diff --git a/libbb/loop.c b/libbb/loop.c
index 256b7ac90..424c39216 100644
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -110,6 +110,51 @@ static int get_next_free_loop(char *dev, int id)
        return loopdevno;
 }
+static int set_loopdev_params(int ffd,
+                int lfd, const char *file,
+                unsigned long long offset,
+                unsigned long long sizelimit,
+                unsigned flags)
+{
+        int rc;
+        bb_loop_info loopinfo;
+        rc = ioctl(lfd, BB_LOOP_GET_STATUS, &loopinfo);
+        /* If device is free, try to claim it */
+        if (rc && errno == ENXIO) {
+                /* Associate free loop device with file */
+                rc = ioctl(lfd, LOOP_SET_FD, ffd);
+                if (rc != 0) {
+                        /* Ouch... race: the device already has a fd */
+                        return -1;
+                }
+                memset(&loopinfo, 0, sizeof(loopinfo));
+                safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
+                loopinfo.lo_offset = offset;
+                loopinfo.lo_sizelimit = sizelimit;
+                /*
+                 * Used by mount to set LO_FLAGS_AUTOCLEAR.
+                 * LO_FLAGS_READ_ONLY is not set because RO is controlled by open type of the file.
+                 * Note that closing LO_FLAGS_AUTOCLEARed lfd before mount
+                 * is wrong (would free the loop device!)
+                 */
+                loopinfo.lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY);
+                rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
+                if (rc != 0 && (loopinfo.lo_flags & BB_LO_FLAGS_AUTOCLEAR)) {
+                        /* Old kernel, does not support LO_FLAGS_AUTOCLEAR? */
+                        /* (this code path is not tested) */
+                        loopinfo.lo_flags -= BB_LO_FLAGS_AUTOCLEAR;
+                        rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
+                }
+                if (rc == 0)
+                        return rc; /* SUCCESS! */
+                /* failure, undo LOOP_SET_FD */
+                ioctl(lfd, LOOP_CLR_FD, 0); // actually, 0 param is unnecessary
+        }
+        return -1;
+}
 /* Returns opened fd to the loop device, <0 on error.
 * *device is loop device to use, or if *device==NULL finds a loop device to
 * mount it on and sets *device to a strdup of that loop device name.
@@ -119,7 +164,6 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
 {
        char dev[LOOP_NAMESIZE];
        char *try;
-        bb_loop_info loopinfo;
        struct stat statbuf;
        int i, lfd, ffd, mode, rc;
@@ -183,45 +227,13 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
                        goto try_next_loopN;
                }
-                rc = ioctl(lfd, BB_LOOP_GET_STATUS, &loopinfo);
+                rc = set_loopdev_params(ffd, lfd, file, offset, sizelimit, flags);
+                if (rc == 0) {
-                /* If device is free, try to claim it */
+                        /* SUCCESS! */
-                if (rc && errno == ENXIO) {
+                        if (!*device)
-                        /* Associate free loop device with file */
+                                *device = xstrdup(dev);
-                        rc = ioctl(lfd, LOOP_SET_FD, ffd);
+                        break;
-                        if (rc != 0) {
-                                /* Ouch... race: the device already has a fd */
-                                goto close_and_try_next_loopN;
-                        }
-                        memset(&loopinfo, 0, sizeof(loopinfo));
-                        safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
-                        loopinfo.lo_offset = offset;
-                        loopinfo.lo_sizelimit = sizelimit;
-                        /*
-                         * Used by mount to set LO_FLAGS_AUTOCLEAR.
-                         * LO_FLAGS_READ_ONLY is not set because RO is controlled by open type of the file.
-                         * Note that closing LO_FLAGS_AUTOCLEARed lfd before mount
-                         * is wrong (would free the loop device!)
-                         */
-                        loopinfo.lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY);
-                        rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
-                        if (rc != 0 && (loopinfo.lo_flags & BB_LO_FLAGS_AUTOCLEAR)) {
-                                /* Old kernel, does not support LO_FLAGS_AUTOCLEAR? */
-                                /* (this code path is not tested) */
-                                loopinfo.lo_flags -= BB_LO_FLAGS_AUTOCLEAR;
-                                rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
-                        }
-                        if (rc == 0) {
-                                /* SUCCESS! */
-                                if (!*device)   /* was looping in search of free "/dev/loopN"? */
-                                        *device = xstrdup(dev);
-                                rc = lfd; /* return this */
-                                break;
-                        }
-                        /* failure, undo LOOP_SET_FD */
-                        ioctl(lfd, LOOP_CLR_FD, 0); // actually, 0 param is unnecessary
                }
- close_and_try_next_loopN:
                close(lfd);
 try_next_loopN:
                rc = -1;
author	Xiaoming Ni <nixiaoming@huawei.com>	2022-12-13 13:13:23 +0100
committer	Denys Vlasenko <vda.linux@googlemail.com>	2022-12-13 14:26:20 +0100
commit	a1856934ba795f81546f5dd9a14ba4faa757ce52 (patch)
tree	8d81c51e88ba4390440be5a63d29524be1dc4765 /libbb
parent	7dc76c9f210b3c66a9c89e6690af7b49f6c540a8 (diff)
download	busybox-w32-a1856934ba795f81546f5dd9a14ba4faa757ce52.tar.gz busybox-w32-a1856934ba795f81546f5dd9a14ba4faa757ce52.tar.bz2 busybox-w32-a1856934ba795f81546f5dd9a14ba4faa757ce52.zip

diff --git a/libbb/loop.c b/libbb/loop.c index 256b7ac90..424c39216 100644 --- a/libbb/loop.c +++ b/libbb/loop.c
@@ -110,6 +110,51 @@ static int get_next_free_loop(char *dev, int id)
110	return loopdevno;	110	return loopdevno;
111	}	111	}
112		112
		113	static int set_loopdev_params(int ffd,
		114	int lfd, const char *file,
		115	unsigned long long offset,
		116	unsigned long long sizelimit,
		117	unsigned flags)
		118	{
		119	int rc;
		120	bb_loop_info loopinfo;
		121
		122	rc = ioctl(lfd, BB_LOOP_GET_STATUS, &loopinfo);
		123
		124	/* If device is free, try to claim it */
		125	if (rc && errno == ENXIO) {
		126	/* Associate free loop device with file */
		127	rc = ioctl(lfd, LOOP_SET_FD, ffd);
		128	if (rc != 0) {
		129	/* Ouch... race: the device already has a fd */
		130	return -1;
		131	}
		132	memset(&loopinfo, 0, sizeof(loopinfo));
		133	safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
		134	loopinfo.lo_offset = offset;
		135	loopinfo.lo_sizelimit = sizelimit;
		136	/*
		137	* Used by mount to set LO_FLAGS_AUTOCLEAR.
		138	* LO_FLAGS_READ_ONLY is not set because RO is controlled by open type of the file.
		139	* Note that closing LO_FLAGS_AUTOCLEARed lfd before mount
		140	* is wrong (would free the loop device!)
		141	*/
		142	loopinfo.lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY);
		143	rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
		144	if (rc != 0 && (loopinfo.lo_flags & BB_LO_FLAGS_AUTOCLEAR)) {
		145	/* Old kernel, does not support LO_FLAGS_AUTOCLEAR? */
		146	/* (this code path is not tested) */
		147	loopinfo.lo_flags -= BB_LO_FLAGS_AUTOCLEAR;
		148	rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
		149	}
		150	if (rc == 0)
		151	return rc; /* SUCCESS! */
		152	/* failure, undo LOOP_SET_FD */
		153	ioctl(lfd, LOOP_CLR_FD, 0); // actually, 0 param is unnecessary
		154	}
		155	return -1;
		156	}
		157
113	/* Returns opened fd to the loop device, <0 on error.	158	/* Returns opened fd to the loop device, <0 on error.
114	* device is loop device to use, or if device==NULL finds a loop device to	159	* device is loop device to use, or if device==NULL finds a loop device to
115	* mount it on and sets *device to a strdup of that loop device name.	160	* mount it on and sets *device to a strdup of that loop device name.
@@ -119,7 +164,6 @@ int FAST_FUNC set_loop(char *device, const char file, unsigned long long offse
119	{	164	{
120	char dev[LOOP_NAMESIZE];	165	char dev[LOOP_NAMESIZE];
121	char *try;	166	char *try;
122	bb_loop_info loopinfo;
123	struct stat statbuf;	167	struct stat statbuf;
124	int i, lfd, ffd, mode, rc;	168	int i, lfd, ffd, mode, rc;
125		169
@@ -183,45 +227,13 @@ int FAST_FUNC set_loop(char *device, const char file, unsigned long long offse
183	goto try_next_loopN;	227	goto try_next_loopN;
184	}	228	}
185		229
186	rc = ioctl(lfd, BB_LOOP_GET_STATUS, &loopinfo);	230	rc = set_loopdev_params(ffd, lfd, file, offset, sizelimit, flags);
187		231	if (rc == 0) {
188	/* If device is free, try to claim it */	232	/* SUCCESS! */
189	if (rc && errno == ENXIO) {	233	if (!*device)
190	/* Associate free loop device with file */	234	*device = xstrdup(dev);
191	rc = ioctl(lfd, LOOP_SET_FD, ffd);	235	break;
192	if (rc != 0) {
193	/* Ouch... race: the device already has a fd */
194	goto close_and_try_next_loopN;
195	}
196	memset(&loopinfo, 0, sizeof(loopinfo));
197	safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
198	loopinfo.lo_offset = offset;
199	loopinfo.lo_sizelimit = sizelimit;
200	/*
201	* Used by mount to set LO_FLAGS_AUTOCLEAR.
202	* LO_FLAGS_READ_ONLY is not set because RO is controlled by open type of the file.
203	* Note that closing LO_FLAGS_AUTOCLEARed lfd before mount
204	* is wrong (would free the loop device!)
205	*/
206	loopinfo.lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY);
207	rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
208	if (rc != 0 && (loopinfo.lo_flags & BB_LO_FLAGS_AUTOCLEAR)) {
209	/* Old kernel, does not support LO_FLAGS_AUTOCLEAR? */
210	/* (this code path is not tested) */
211	loopinfo.lo_flags -= BB_LO_FLAGS_AUTOCLEAR;
212	rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
213	}
214	if (rc == 0) {
215	/* SUCCESS! */
216	if (!device) / was looping in search of free "/dev/loopN"? */
217	*device = xstrdup(dev);
218	rc = lfd; /* return this */
219	break;
220	}
221	/* failure, undo LOOP_SET_FD */
222	ioctl(lfd, LOOP_CLR_FD, 0); // actually, 0 param is unnecessary
223	}	236	}
224	close_and_try_next_loopN:
225	close(lfd);	237	close(lfd);
226	try_next_loopN:	238	try_next_loopN:
227	rc = -1;	239	rc = -1;