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linux-sgx: Use non-destructive modes for opening files using SGX IPFS (#1645)

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Refer to https://github.com/bytecodealliance/wasm-micro-runtime/pull/1645
This commit is contained in:
Jämes Ménétrey
2022-10-27 06:21:30 +02:00
committed by GitHub
parent 15d645476a
commit 264fdfafed
2 changed files with 26 additions and 12 deletions
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17
core/shared/platform/linux-sgx/sgx_ipfs.c
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@ -260,22 +260,27 @@ ipfs_fopen(int fd, const char *filename, int flags)
bool write_only = (flags & O_ACCMODE) == O_WRONLY;
bool read_write = (flags & O_ACCMODE) == O_RDWR;
// The mapping of the mode are described in the table in the official
// The mapping of the mode is similar to the table in the official
// specifications:
// https://pubs.opengroup.org/onlinepubs/9699919799/functions/fopen.html
// Note that POSIX has obtained a file descriptor beforehand.
// If opened with a destructive mode ("w" or "w+"), the truncate operation
// already occurred and must not be repeated because this will invalidate
// the file descriptor obtained by POSIX. Therefore, we do NOT map to the
// modes that truncate the file ("w" and "w+"). Instead, we map to a
// non-destructive mode ("r+").
if (read_only)
mode = "r";
else if (write_only && must_create && must_truncate)
mode = "w";
// Rather than "w", we map to a non-destructive mode
mode = "r+";
else if (write_only && must_create && must_append)
mode = "a";
else if (read_write && must_create && must_truncate)
mode = "w+";
else if (read_write && must_create && must_append)
mode = "a+";
else if (read_write && must_create)
mode = "w+";
else if (read_write)
// Rather than "w+", we map to a non-destructive mode
mode = "r+";
else
mode = NULL;